University of Arkansas at Little Rock

94th Annual Meeting of the
Arkansas Academy of Science
April 9-10, 2010
University of Arkansas at Little Rock

Oral Presentation Abstracts

Biology Talks

 

1.     New Records of the Badger (Taxidea Taxus) in Arkansas, with Emphasis on Range Expansion into NorthEastern Arkansas

 

Tumlinson, Renn¹; Sasse, D. Blake²; Cartwright, Michael E.²; Brandenbura, Stephen C.³; Klotz, Tracy³

¹Henderson State University

²Arkansas Game and Fish Commission

³Arkansas State University

 

In Arkansas, only scattered and occasional records have been documented for the badger (Taxidea taxus). Within the last decade, however, several observations of badgers have been obtained in northeastern Arkansas. Most records were based on roadkill individuals, of which several were documented in photographs. Badger populations have expanded their range as far down as Crittenden County, where a farmer with a wildlifeThe bioavailability of citrulline depends on the production of citrulline from other amino acids by enterocytes. The health of enterocytes is greatly affected by radiation common in cancer treatments. Therefore, citrulline may be used as a biomarker for radiation-induced intestinal damage. However, there is no adequate calibration matrix for citrulline since it is an endogenous compound. It was the goal of this project to develop a double isotope, ultra-performance/tandem mass spectrometry (UPLC-MS/MS) method for the determination of plasma citrulline concentrations. Top-spiked plasma samples were treated with various solutions for protein precipitation to observe optimal linearity of samples. Matrix ion effects were studied by post-column infusion of citrulline. Optimized extractions were obtained with 95% acetonitrile (with 0.2% formic acid) and resulting in peak area versus concentration graphs with R2 = 0.9961. Samples were filtered us ing 96-well extraction plate. The contributions of citrulline and citrulline +1 to each other were observed to. determine the proper use of isotopes as the calibration or internal standard. This methodology was used to determine plasma citrulline in mice and rats challenged with escalating doses of radiation. camera was able to document a den of five badgers. It is believed that badger populations have expanded in recent years from the Ozark physiographic region into the bootheel of Missouri, and from there likely have dispersed along Crowley’s Ridge and the St. Francis River in northeastern Arkansas.

 

 

2.     New Records and Notes on the Natural History of Selected Vertebrates from Southern Arkansas

 

Tumlinson, Renn¹; Robison, Henry²

¹Henderson State University

²Southern Arkansas University

 

Knowledge of the distribution of vertebrates in southern Arkansas is less precise than for the northern portions of the state. During recent years, several collections have provided locality data for species that, when compared with published books concerning vertebrates in Arkansas, reveal new information about the range and natural history of those species. Herein we present new records of fishes, amphibians, reptiles, birds, and mammals in southern Arkansas.

 

 

3.     Distribution of the southeastern shrew (Sorex longirostris) in Arkansas

Mikel, Garrett A.; Clark, David W.

University of Arkansas at Little Rock

The southeastern shrew (Sorex longirostris) is considered uncommon and a Species of Special Concern in Arkansas. Six captures, since Sealander and Heidt’s (1990) Arkansas Mammals focused on summarizing and discussing occurrence, document a new physiographic region and 3 new counties. We evaluated persistence at previous capture sites, surveyed across Arkansas including the upper Mississippi Alluvial Plain, quantified microhabitat at our capture locations, and compiled occurrences. Number of specimens in Arkansas has increased to 16 in 12 counties within the Ozark Plateau, Ouachita Mountains and Arkansas River Valley Sections. Efforts to assess a potential distribution gap in the Mississippi Alluvial Plain produced only southern short-tailed shrew (Blarina carolinensis) and least shrew (Cryptotis parva) captures; therefore, possible factors affecting species connectivity across the Mississippi River Basin are discussed. Given sparse records in Arkansas, uncommon and Species of Special Concern designations are warranted.

 

 

4. Future climate change spells catastrophe for Blanchard’s Cricket Frog (Acris blanchardi)

 

McCallum, Malcolm

Herpetological Conservation and Biology

 

Climate change may be one of the greatest environmental catastrophes encountered by modern human civilization. The potential influence of this global disaster on wildlife populations is subject to question. I interpolated how seasonal variation in weather patterns influences growth and reproduction in the Northern Cricket Frog (Acris crepitans). Then I extrapolated the influence of future climate conditions on these life history characteristics using fuzzy regression. Fuzzy regression was an accurate predictor of growth and reproduction based on the climate conditions present from 1900–2007. It predicted that the climate projections expected for Arkansas by 2100 could reduce total reproductive investment in the Northern Cricket Frog by 33–94%. If these results reflect responses by other poikilotherms, climate change could induce major population declines in many species. Because poikilotherms represent the vast majority of vertebrates and significant ecosystem components, it is imperative that we implement strategies to reduce greenhouse gas emissions and circumvent this possible catastrophe.

 

 

5. The tempo of amphibian declines and extinctions

 

McCallum, Malcolm

Herpetology Conservation and Biology

 

Recent studies suggested that amphibian declines are advancing at hundreds to thousands of times the rate of amphibian background extinctions (ABE). The causes of this phenomena range from habitat loss to climate change, and interactions among multiple stimuli are likely. I used fuzzy arithmetic to compare current extinctions and declines of amphibian families and orders to published estimates of the rate of ABE. Although the Anura had the most extinct and declining species, caudates were at a higher risk of extinction. This is probably related to the lower species diversity in the Caudata. There is not enough information to reliably determine rates for Gymniophona. There were 32 (69%) amphibian families containing declining species with 22 (46%) of these declining more than 1000 times the amphibian background extinction rate. My analyses supported assertions that current amphibian declines are proceeding at catastrophic rates and that these declines are not generally confined to specific families but tend to be widely distributed across amphibian taxa.

 

 

6.     American Woodcock Migration Chronology and Clearcut use within Central Arkansas

 

Long, Andrea; Felix-Locher, Alexandra

University of Arkansas at Monticello

 

American woodcock (Scolopax minor) populations have experienced long-term population declines over the past 40 years. No information on their wintering ecology exists for Arkansas although areas have been identified as important stopover grounds during their fall migration; particularly areas within the industrial forests of southeastern Arkansas. It is important that winter habitat use be quantified to further conservation of woodcock populations and habitat. The goal of my study is to enhance the understanding of woodcock winter ecology as well as the conservation of woodcock habitat within the state of Arkansas. In particular, we are interested in the effect of clearcut age on woodcock use and their migration chronology. To gather this information, clearcuts have been divided into three groups; new, young pine plantation, and older pine plantations with trees less than 3 m. Each week, three of each treatment type are surveyed during the crepuscular period for a total of nine fields. The same clearcuts are surveyed each week to document migration. Thermal imaging is also being used to document migration and nocturnal habitat use in clearcuts. Three routes are travelled weekly with the camera. We will present preliminary results from the first field season in relation to woodcock clearcut use and migration chronology in Arkansas. This information is important because forestry is a large industry within Arkansas. Understanding how management practices affect woodcock and when their peak-use occurs in Arkansas can help mold conservation efforts and direct management decisions.

 

 

7.     Status and Distribution of the Gapped Ringed Crayfish, Orconectes neglectus chaenodactylus, in Arkansas

 

Wagner, Brian K.; Taylor, Christopher A.; Kottmyer, Mark D.


Arkansas Game and Fish Commission

 

Orconectes neglectus chaenodactylus, the gapped ringed crayfish, is an uncommon and poorly-known stream-dwelling crayfish that is endemic to the central White River basin of Arkansas and Missouri. This study surveyed a semi-random selection of stream sites in the Arkansas portion of this range in order to characterize the crayfish communities and evaluate the status of O. n. chaenodactylus in Arkansas. Collections of a total of 1,107 individual crayfish specimens were made at 82 sites, including 497 O. n. chaenodactylus from 21 sites. O. punctimanus was the crayfish species most commonly associated with O. n. chaenodactylus, occurring at 71% of sites occupied by O. n. chaenodactylus. O. n. chaenodactylus was found in streams not significantly different from the median characteristics of streams sampled in the study. It is our opinion that O. n. chaenodactylus is of moderate concern due to its limited distribution in Arkansas, and should be considered uncommon.

 

 

8.     Genetic Analysis of Largemouth and Florida Bass in Arkansas Lakes Using Microsatellites

 

Richardson, Jasmine; Gadbury, Melissa; Cato, Christopher; Johnson, Ronald L.


Arkansas State University

 

The extent and effects of hybridization between the largemouth bass (Micropterus salmoides) and introduced Florida bass (M. floridanus) in southern lakes has been a great source of debate. Previous genetic studies investigating hybridization of these two species have often lacked sufficient resolving power to distinguish specific hybridization events. The goal of this study was to determine the incorporation of Florida bass alleles into several Arkansas lakes. To achieve this goal, a suite of seven microsatellite markers capable of distinguishing largemouth bass, Florida bass, and their hybrids were employed to categorize over 2000 individuals from 8 southern Arkansas lakes (Lakes Chicot, Columbia, DeGray, Erling, Millwood, Monticello, Ouachita and SWEPCO). These lakes had differing Florida bass stocking histories, ranging from no previous introductions to extensive and continued stocking. SNA extraction was performed on bass fin clips, microsatellite loci were amplified using PCR, and alleles were separated using capillary electrophoresis. The software Structure was used to analyze the distribution of microsatellite loci within individuals and populations, cataloging allele frequencies, and for admixture analyses. Largemouth bass allele frequencies ranged from 0.29 (Lake Monticello) to 0.99 (Brushy Creek of Lake DeGray) for the composite of the loci studies. Allele frequencies and cluster analysis are largely consistent with that predicted based upon stocking histories and protocols.

 

 

9.   Noteworthy distribution records for the Endemic Redspotted Stream Crayfish, Orconectes Acares (Decapoda: Cambaridae) in Arkansas

 

McAllister, Chris T.¹; Robison, Henry W.²

¹RapidWrite

²Southern Arkansas University

 

There has been a recent increase in interest in the study of the crayfishes of Arkansas. Indeed, crayfishes are an important component of aquatic habitats and serve a role as food source for many vertebrates. One of these species, the redspotted stream crayfish, Orconectes (Procericambarus) acares Fitzpatrick is a relatively small decapod that is endemic to tributaries of the Ouachita River in 7 counties of the state. Between April 1996 and October 1997, March and May 2000, and again between October 2009 and April 2010, we attempted collections of O. acares in small streams in the Ouachita National Forest (ONF) of Arkansas and Oklahoma. In addition, we searched 3 of the larger online museum computer databases in an attempt to document records of O. acares not previously published. Several new localities are documented as well as a new county record (Clark County) for O. acares. This crayfish was found at 125 of 251 sites in Arkansas during the study period for a total of 1,258+ specimens. Interestingly, no O. acares were found at any of the 204 collecting sites on the Oklahoma side (LeFlore and McCurtain counties) of the ONF. This Ouachita River endemic has its distribution centered within the ONF and thus its high abundance should be expected. It was collected in all major tributaries of the Ouachita River drainage, including the Caddo, Little Missouri, Ouachita, and Saline Rivers. Together with the western painted crayfish (Orconectes palmeri longimanus), O. acares is 1 of the 2 most abundant crayfishes in the Arkansas portion of the ONF. One of the most interesting specimens of O. acares was collected from Perry County (USNM 217145), part of the Fourche La Fave River basin.

 

 

10. Distribution and Life History Aspects of the Freshwater Shrimps, Macrobranchium and Palaemonetes (Decapoda: Palaemonidae), in Arkansas

 

Robison, Henry W.¹; McAllister, Chris T.²; Harp, George L.³

¹Southern Arkansas University

²RapidWrite

³Arkansas State University

 

Freshwater shrimp are conspicuous members of Arkansas’ aquatic macroinvertebrate fauna and yet they have received little attention. In Arkansas, freshwater shrimp are represented by the Ohio shrimp, Macrobrachium ohione Smith, and the Mississippi grass shrimp, Palaemonetes kadiakensis (Holthuis). Little is known about the distributional limits of these shrimps in Arkansas and even less about their natural history, including ecology, reproductive biology, habitat characteristics, and general biology. Limited previous collecting of these species is primarily responsible for this lack of knowledge. The present survey of the shrimps of Arkansas is based on collections made between 1974 and 2008. In addition, museum specimens housed at the United States National Museum of Natural History (USNM), Illinois Natural History Survey, and the G. L. Harp Aquatic Macroinvertebrate Collection, Arkansas State University were used to document the overall distribution of the 2 species in the state. Our survey found a total of only 42 specimens of M. ohione from 6 localities (2 counties) in Arkansas, all taken from the Mississippi River. Specimens were seined over sandy substrates in 2-3 feet of water without vegetation. A collection of 5 individual M. ohione housed in the USNM was collected in 1914 from the Mississippi River at Helena, Phillips County. This represents the only known occurrence of M. ohione from Phillips County. All other specimens were taken between 1974-1975 by the first author (HWR) in the Mississippi River near the U.S. Hwy. 82 bridge (Chicot County). It appears that M. ohione is a relatively rare shrimp in Arkansas. Since specimens were documented from a single drainage system (Mississippi River) in only 2 counties, we recommend a “threatened” conservation status of M. ohione in Arkansas because of this restricted distributional range. On the other hand, P. kadiakensis is relatively abundant in Arkansas. It had previously been reported from 10 counties of the state. Over 4,500 specimens of P. kadiakensis were documented during this study from various sites in 47 counties and most were released at their capture site. Grass shrimp were commonly found in sluggish backwater regions of streams especially preferring heavily vegetated lentic areas of pool regions. Mississippi grass shrimp have remained abundant and widespread in occurrence for the past 35 years. The Nature Conservancy lists populations of P. kadiakensis as secure (G5) in rounded global status. Indeed, Mississippi grass shrimp populations in Arkansas are also secure and in no need of special protection.

 

 

11.  Structure and function of large wood in Ozark headwater streams and its effect on fish community structure

Mitchell, David; Entrekin Sally; Adams, Ginny; Adams, Reid

University of Central Arkansas

Large wood (LW) performs several functions in streams including altering flow, sediment retention, bank stabilization, and pool formation. Single pieces of LW and other woody structures, such as, organic accumulations and root wads increase habitat complexity. A literature review indicates that streams in the Ozark Plateau region of the United States contain less LW than streams in any other geographic region and our study is among the few studies exploring the importance of LW to fish community structure in the region. One hundred meter reaches were delineated in ten Ozark streams representing a gradient of large wood volumes. LW structures were quantified within each reach and fish were captured, identified, counted, and weighed. Total volume of single LW pieces, root wads and organic accumulations ranged from 339 to 4911m3. Most LW stabilized banks or stored sediment and gravel. Creek chub (Semotilus atromaculatus) were positively relate d to organic accumulation volume (p=0.008, r2=0.71). Algivorous taxa were composed predominantly of southern redbelly dace and were also positively related to organic accumulations (p=0.004, r2=0.41). Insectivorous and generalist species were not related to changing volumes of large wood. Extensive timber harvest and subsistence agricultural practice has depleted much of the Ozark’s old growth timber stands leading to increased aggradations of stream channels, young riparian timber stands, and lower rates of natural LW recruitment to stream channels. Considering the low levels of LW in Ozark streams it is likely that past land use has altered stream fish communities throughout the region.

 

 

12.  Movement Patterns and Environmental Influences of Two Cyprinids in an Intermittent Reach of an Ozark Stream

 

Walker, Richard H.; Adams, Ginny; Adams, S. Reid

University of Central Arkansas

 

Previous research in perennial headwater systems has shown the majority of fishes exhibit restricted movement; however, few studies have tested the restricted movement hypothesis in an intermittent stream where resource availability is often patchy relative to perennial streams. Our obejctives were to examine movement patterns of southern redbelly dace (Chrosomus erythrogaster) and creek chub (Semotilus atromaculatus), two small-bodied fishes common in a 5958m reach of an intermittent headwater stream and to determine the environmental factors influencing these movement patterns. A total of 4744 C. erythrogaster and 406 S. atromaculatus were tagged with elastomer over the first two sample trips. Capture efficiency was high for both  C. erythrogaster  (97%) and  S. atromaculatus (94%) and recapture rate varied from 23% to 10% respectively. Mark-recapture results indicated a high percentage of recaptures during the Fall season remained within the original pool of capture (68% for C. erythrogaster and 42% for S. astrmaculatus). However, some individuals did move long distances: 5,732 m for C. erythrogaster and 1,088m for S. astrmaculatus. These long exploratory movement behaviors may be a means to evaluating alternative habitats for additional resource requirements. Mark-recapture data relating environmental parameters with movement and persistence of individuals will be discussed further.

 

 

13.  Ultrastructural Observations of the Secretory Epithelium of the Distal Genital Tract in the Flathead Snake, Tantilla gracilis

 

Trauth, Stanley E.

Arkansas State University

 

I examined the secretory epithelium of the distal genital duct system of reproductively-active male Flathead Snakes, Tantilla gracilis, using transmission electron microscopy (TEM). Snakes were collected from the Interior Highlands ecoregion of Arkansas between early April 2007 and mid-May 2008. Specimens were returned to the lab and sacrificed using sodium pentobarbital. The genital ducts were excised and prepared for TEM using routine histological and ultrastructural techniques. I focused this study on three distinct regions of a genital duct: the more proximal ductus deferens, an enlarged distal segment known as the ampulla ductus deferentis, and the most caudal portion, the ampulla urogenital papilla. The secretory epithelial cells in these areas varied from low cuboidal columnar in the ductus deferens to a pseudostratified columnar type within the ampulla ductus deferentis. Apical cell surfaces contained low-to-tall microvilli, and secr etory activity ranged from merocrine to an apocrine discharge. Sperm aggregates associate closely with the epithelial surfaces in all ductal regions. It remains unclear as to the functional significance of secretory products released by the epithelia within this duct system.

 

 

14.  The histology, histochemistry, and ultrastructure of Rathke’s glands in the Mississippi mud turtle, Kinosternon subrubrum hippocrepis, in Arkansas

Webb, Sarah J.; Trauth, Stanley E.

Arkansas State University

Rathke’s glands are found in both extinct and extant turtle species, specifically in both megaorders Pleurodira and Cryptodira. The glands are homologous in all turtles and are thought to be the most ancient vertebrate integumentary gland. We examined the anatomy of Rathke’s glands in the Mississippi mud turtle, Kinosternon subrubrum hippocrepis. We used museum specimens collected from eight counties within Arkansas from 1989-2009. This species has two pairs of glands, one axillary and one inguinal, which are usually bi-lobed. The glands are holocrine and externally secreting, composed of columnar epithelium, and surrounded by connective tissue and striated muscle. We utilized light, scanning electron, and transmission electron microscopy (as well as using histochemical methods) during the examination of the glands. We observed two distinct types of secretory vacuoles within the gland, similar to the findings of other studies performe d on other turtle species. No significant differences in gland size or structure were found according to gender or maturity in the Mississippi mud turtle.

15.  An Urban Population of Western Lesser Sirens, Siren intermedia nettingi

Sawyer, Jacob A.; Trauth, Stanley E.

Arkansas State University

We conducted a study of the Western Lesser Siren (Siren intermedia nettinigi), at a locality termed the Airport Road site in Jonesboro (Craighead County, AR) from November 2004 until March 2007. This site consisted of a network of roadside ditches in cultivated lawns in an industrial park. Even though sirens are known to occur frequently in ditches, most studies within the genus (Siren) have taken place in natural wetlands. We compiled mark-recapture data at the Airport Road site for each season to determine if the seasonal activity pattern for sirens in northeast Arkansas varied from activity data previously published from other localities in the range of this species. Capture rates were higher in the fall and spring. The predicted overall population size was 110 sirens at a density of 0.81 sirens per linear m. This density was less than the densities (in sirens/m2) reported by previous studies. We found two prominent peaks in sirens p er size class: the first at 161-170 mm, and the second at 201-210 mm. Other researchers have assumed that the two most abundant size classes in siren populations represent one-year-old and two-year-old cohorts. The sirens captured at the Airport Road site are smaller, on average, than those reported in previous population studies. We found no significant difference between the growth rates of sirens larger than 200 mm SVL and those smaller than 200 mm snout-vent length (= SVL; P = 0.957, confidence interval -1.945, 2.045, n = 16). Our mean growth rates did not significantly differ from growth rates reported for sirens elsewhere. We sectioned siren humeri to identify and quantify lines of arrested growth (LAGs) as part of a skeletochronological analysis. The use of SVL was a poor indicator of number of LAGs. The difference in the weather pattern history in each of the voucher sirens used likely resulted in broad ranges of LAGs for each SVL size class.

16.  Seasonal activity of the Ozark Highlands leech, Macrobdella diplotertia, in north-central Arkansas

Connior, Matthew B.¹; Trauth, Stanley E.²

¹South Arkansas Community College

²Arkansas State University

The Ozark Highlands leech, Macrobdella diplotertia, occurs intermittently throughout Arkansas, Kansas, and Missouri. Limited natural history of this species is known. Herein, we report a new county occurrence for this leech from a cattle pond in Marion County, Arkansas. We also report on the seasonal activity and novel hosts of this species. We surveyed the inhabited pond monthly to determine activity and collect natural history data on this species. This study indicates that this species seems to be most active in spring, summer, and early fall, but inactive during the winter. We also documented three new anuran hosts for this species. The central newt, Notopthalmus viridescens viridescens, was also present in this pond, which further supports the mimetic relationship these two species exhibit.

17.  Hurricane Birds in Arkansas in 2008

James, Douglas A.; Smith, Kimberly G.; Neal, Joseph C.

University of Arkansas

In the fall of 2008, three hurricanes made landfall on the Gulf Coast south of Arkansas. These storms progressed inland and impacted Arkansas. Seven bird species that are rare in the state, but occur regularly along the Gulf Coast, were noted by numerous observers. Almost all of these extralimital species were associated with Hurricane Gustav that reached Arkansas on September 2. None of these bird occurrences were new for the state, but the number of species and individual birds involved was the highest ever recorded in Arkansas. The first hurricane, Dolly, produced a new species for the state. No new species or rare birds are known to have been associated with the last of the three hurricanes, Ike.

18.  Effects of Ligustrum Sinense Eradication on Avian Abundance and Species Richness in Central Arkansas

Needham, Jessica R.; Larson, Katherine C.

University of Central Arkansas

Ligustrum sinense is one of the most common exotic and invasive plant species in Arkansas forests, and in many locations, it is being actively managed through cutting, spraying the stumps with herbicide, and burning. However, little is known about the effects of L. sinense and these management strategies on avian abundance and species richness. The main goal of this study is to determine if cutting and spraying L. sinense affects avian abundance and species richness. This study tests the hypothesis that areas where L. sinense has been cut and sprayed but still lies in piles will have higher avian abundance and species richness than areas where L. sinense remains untouched. Species richness was found to be higher in the cut L. sinense plot, but there was no difference in abundance. The urban nature reserve where this study is being conducted contains remnants of native prairie as well as L. sinense invaded areas. A secondary goal of this study is to test the hypothesis that the urban nature reserve containing native vegetation has higher avian abundance and species richness than a nearby urban nature reserve lacking native vegetation. We found little effect on daily species richness and abundance, however, more total species, including one of conservation concern, were observed in the nature reserve with native vegetation.

 

19.  Presence of the Asian Tiger Mosquito (Aedes albopictus) in Northwest Arkansas

Wilson, Jill; Jamieson, David H.

NorthWest Arkansas Community College

In the fall semester of 2008 and 2009, students enrolled in freshman biology courses at NorthWest Arkansas Community College participated in a survey to determine if the Asian tiger mosquito (Aedes albopictus) was the principal pest mosquito in late-summer/early-fall in Northwest Arkansas. Since its arrival in Houston, TX in 1985, this species has become widespread in the Eastern United States. Its ability to restrict outdoor human activity and vector disease has many public health professionals concerned. Eight species representing four genera were collected. A. albopictus represented 79% of all mosquitoes collected during the study. The second most frequently collected species was the house mosquito (Culex pipiens); it only comprised 6% of mosquitoes collected. C. pipens is believed to be a major vector of West Nile fever in this region.

20.  Arkansas bug update 2010; including 1 extremely rare bug

Chordas III, Stephen¹; Tumlison, Renn²; Robison, Henry³; Connior, Matthew⁴

¹The Ohio State University

²Henderson State University

³Southern Arkansas University

⁴Southern Arkansas Community College

 

More than a dozen species of Hemiptera (representing a variety of bug families) have been identified as new state records for Arkansas over the past year. Our 2010 bug update includes these new Arkansas state records of true bugs, photographic representation of the species, as well as current North American distributions. One of these species, encountered in 2008 in the Ouachita National Forest, Garland County, was of particular interest. This species is perhaps one of the rarest bugs in North America. Identification, distribution and a more detailed history of this rare bug will be featured.

 

 

21.  Endocrine disruption of sexual selection in the mealworm beetle (Tenebrio molitor)

 

McCallum, Malcolm L.¹; Treas, Justin²; Matlock, Mackenzie³; Safi, Barroq⁴; Sanson, Wendy⁵; McCallum, Jamie L.⁶

¹Herpetological Conservation and Biology

²Texas Tech University

³Texas Tech University-Texarkana

⁴Texas State University

⁵Louisiana State University-Shreveport

⁶McCallumsflock.com

 

The role that endocrine disruption could play in sexual selection remains relatively untested. Although estrogens occur in insects, little information exists about their biological role. Atrazine is a commonly applied herbicide that mimics estrogen in vertebrates. We raised Tenebrio molitor from egg to adult under a gradation of atrazine exposures and a control. We delivered atrazine in the drinking water. We provided female T. molitor with a choice between unrelated males raised under three levels of atrazine exposures. Females showed no preference between the control and the high exposure level. Excluding the control, female preference increased as exposure increased. These results have important repercussions for nonlethal effects of endocrine disruption on populations, their capacity to interfere with sexual selection, and the role of estrogen in pheromone communication among insects.

 

 

22.  Rare Comanche Harvester Ants in Arkansas–What Do We Know?

Thompson, Lynne C.; General, David M.

University of Arkansas at Monticello

We discovered a substantial population of the rare Comanche harvester ant (Pogonomyrmex comanche) at Arkansas Oak Natural Area in Nevada County. This talk provides an overview of what is known about this rare species, especially the importance of soils. Additional smaller populations have since been found in Miller and Ouachita Counties.

23.  Further Sampling in Arkansas of Insects Inhabiting the Burrows of Baird’s Pocket Gopher

Kovarik, Peter W.¹; Connior, Matthew B.²; Chordas III, Stephen W.³; Skelley, Paul E.⁴; Robison, Henry W.²

¹Columbus State Community College

²Southern Arkansas University

³The Ohio State University

⁴Florida State Collection of Arthropods

Pocket gopher burrows provide a stable environment for a variety of invertebrate and vertebrate inquelines. Most of the arthropods inhabiting pocket gopher burrows are restricted to this microhabitat. Current sampling efforts are part of a state-wide biotic survey project of insects inhabiting the burrow of Baird’s pocket gopher in Arkansas. Pitfall traps were established in gopher burrows and nests and associated chambers were excavated in 2009 and 2010. Samples of insects have been retrieved from Logan, Franklin, Union, Ouachita, Sebastian, and Scott Counties. Retrieved samples contained mainly scarab, histerid, and rove beetles, cave crickets and anthomyiid flies. Significant results include the discovery of Cryptoscatomaseter acuminatus (Cartwright) in Ouachita County. This represents a new state record as this species was formerly known only from Texas, Louisiana, and Nebraska. Other significant results include range extensions for two r arely-collected beetles. The histerid Margarinotus felipae (Lewis) was taken in Scott County and the scarab Euphoria discicollis Thompson was taken in both Scott and Sebastian Counties.

24.  New Records and Notes on the Natural History of Selected Invertebrates from Southern Arkansas

Tumlinson, Renn¹; Robison, Henry²

¹Henderson State University

²Southern Arkansas University

Generally being perceived as less glamorous than vertebrates, many arthropods have received relatively little attention in southern Arkansas. Herein, we report a neotropical spider, the golden orb weaver (Nephila clavipes) new for the state. The general range of this species extends along the Gulf Coastal States of the southern United States. Another neotropical species, known as ‘love bugs” (Plecia americana) also are reported for the first time. Also, we report significant new records of the crayfish species Fallicambarus petilicarpus, Fallicambarus fodiens, Faxonella clypeata, Oronectes lancifer, Procambarus ouachitae, and Procambarus tulanei.

 

 

25.  Search for a “silver bullet.”

Black, Viktoriya; Njewel, Guy

Southern Arkansas University

The authors reviewed literature on the application of the silver containing compounds incorporated in the surfaces of large variety of medical devices including vascular, urinary, peritoneal catheters, endotracheal tubes, sutures, and fractures fixation devices as well as in other materials such as plastics of the kitchen appliances and fabrics. Researchers found renewed and rising interest in silver containing materials due to its antimicrobial including antiviral and antifungal properties, good toxicology and environmental records. Silver containing compounds could be used against bacterial strains that are known to be resistant to the antibiotics. More research is necessary to determine safe levels and particles size of the silver for use in humans.

26.  The effectivness of the weight control throught the weight watch programs

Black, Viktoriya; Boumtje, Pierre

Southern Arkansas University

As the prevalence of overweight and obesity is increasing, so is the awareness of their health consequences among the public. This growing consciousness is translated by the spread of weight watch programs aimed at establishing healthy lifestyles that will reduce weight for participants. Few studies, if any, have attempted to link participation in weight loss programs to reduction in Body Mass Index (BMI) of participants. This study uses Ordinary Least Square estimation and survey data to determine what specific lifestyles and diets habits would substitute to clinical care in reducing and controlling weight. Specifically, the study intends to: (1) Examine and assess the likelihood of participation in weight loss programs in reducing the Body Mass Index, (2) Estimate and quantify the effect of selected demographic factors, food consumption patterns, and physical exercise habits. (3) Provide important policy implications to public health officials with respect to the development of nutritional education, and information delivery, if needed as the potential health benefits from reduction in overweight and obesity are of considerable public health importance. Preliminary results show substantial association between specific lifestyles and diet habits, and changes in the BMI of participants.

27.  Sequence Differences among CYP3A Members Significantly Impact the Metabolism of R- and S-Warfarin

Jones, Drew R.¹; So-Young, Kim²; Yun, Chul-Ho³; Boysen, Gunnar¹; Miller, Grover P.¹

¹University of Arkansas for Medical Sciences

²Chonnam National University

Given as an equimolar mixture of R and S isomers, Coumadin (warfarin) is one of the most widely-used anticoagulant drugs in the world; nevertheless, its use is complicated by a narrow therapeutic range and high inter-individual variability in response to treatment. Warfarin undergoes extensive metabolism to less active or inactive metabolites, hence, there has been significant interest in identifying and understanding the role of specific enzymes in warfarin metabolism. CYP3A4 metabolizes over half of the drugs on the market including R- and S-warfarin. Recent drug-drug interaction studies have demonstrated that CYP3A4 contributes to patient responses to anticoagulant therapy. Little is known about the role of other CYP3A enzymes, namely 3A5 and 3A7, in warfarin metabolism. Genetic polymorphisms for both enzymes result in elevated hepatic levels and a more significant contribution to metabolism. Moreover, CYP3A expression undergoes a trans ition from “fetal” CYP3A7 to adult CYP3A4, which could impact active drug levels and consequently pediatric response to warfarin therapy. In this study, we report the first investigation of R- and S-warfarin metabolism by recombinant CYPs 3A5 and 3A7 and include studies with recombinant CYP3A4 for comparative purposes. Our steady-state studies demonstrated that all CYP3A enzymes generate the same products, namely, R/S-10- and 4´-hydroxywarfarin; however, the metabolic efficiencies for these reactions were distinct for CYPs 3A4, 3A5, and 3A7. R-warfarin was most efficiently metabolized to R-10-hydroxywarfarin for each of the three enzymes, with R-4´-hydroxywarfarin warfarin being produced with 22, 5, and 11-fold lower efficiencies for CYPs 3A4, 3A5, and 3A7 respectively. Metabolic efficiency toward S-warfarin was lower as compared to R-warfarin, with S-10-hydroxywarfarin and S-4´-hydroxywarfarin being produced in unique ratios for each of the three enzymes. Overall , CYP3A4 was the most efficient metabolizer of warfarin with CYP3A5 being less efficient and CYP3A7 showing even lower metabolic efficiency. These results suggest that individuals with higher relative levels of either CYP3A5 or CYP3A7 compared to CYP3A4 may metabolize warfarin less efficiently, and thus may require lower doses and be at risk for adverse drug-drug interactions dependent on the drug specificities of the respective CYP3A enzymes.

28.  CYP2C19 Metabolizes Both R- and S-Warfarin to Enantiomers of Four Hydroxywarfarins

Kim, So-Young¹; Jones, Drew R.²; Yun, Chul-Ho¹; Boysen, Gunnar²; Miller, Grover P.²

¹Chonnam National University

²University of Arkansas for Medical Sciences

Despite the widespread use of Coumadin (R/S-warfarin) in anticoagulant therapy, the metabolism of the drug by patients remains an important contributor to the uncertainties in patient response to therapy. Drugs targeted by CYP2C19 for oxidative metabolism have been shown to lead to toxic levels of warfarin, presumably due to competition for CYP2C19. The potential importance of CYP2C19 in warfarin metabolism was validated by recent pharmacogenetic studies. Those efforts demonstrated that CYP2C19 polymorphisms impacted therapeutic outcomes. Nevertheless, a mechanistic basis for these observations is not possible due to limited details on CYP2C19 metabolism of warfarin by others. To address this gap in knowledge, we investigated the metabolic efficiency of CYP2C19 toward R- and S-warfarin under steady-state conditions using in vitro systems. Recombinant CYP2C19 metabolized R-warfarin to R-6-, 7-, and 8-hydroxywarfarin as major metabolites, while p roducing R-4’-hydroxywarfarin as a minor metabolite. The recombinant enzyme generated these same metabolites during S-warfarin metabolism. In this case, S-6-hydroxywarfarin was the only major product of the reaction and in fact, was the most efficiently generated metabolite between both warfarin isomers. Based on total metabolites, R-warfarin was much more efficiently metabolized by CYP2C19 than S-warfarin. As a model for liver metabolism, we assessed R- and S-warfarin metabolism by human liver microsomes. Through inhibitor phenotyping for specific P450s, we validated the role of CYP2C19 in metabolic pathways predicted by studies with the recombinant enzyme. Furthermore, we demonstrated that CYP2C19 was a major determinant of R-warfarin metabolism and also played a minor role in S-warfarin metabolism. Our findings suggest that the biological relevance of CYP2C19 during anticoagulant therapy most likely manifests in its role in R-warfarin and not S-warfarin metabolism.

29.  Antigenicity Determination and Characterization of an Anti-peptide Polyclonal Antibody against Human Multiple Inositol Polyphosphate Phosphatase (MINPP) to Study its Physiological Function

Hossain, Md. Zakir; Kleve, Maurice G.

University of Arkansas at Little Rock

Antibodies are useful tools to characterize structure and function of proteins. The multiple inositol polyphosphate phosphatase (MINPP), located on human chromosome 10q23, belongs to a family of histidine phosphatases, encodes an enzyme which regulates cellular inositol phosphate levels. Inositol phosphates in turn regulate cellular processes like Ca++ homeostasis, metabolic pathways, vesicular trafficking, chromatin remodeling, mRNA exporting etc. MINPP contains a tetra peptide sequence called KDEL at its c-terminal end that is an indication of soluble luminal protein of endoplasmic reticulum. In this study, we have determined the antigenicity of MINPP and predicted possible peptides to be used for rabbit immunization. An N-terminal peptide, DLI QVA FFT CSF DLA IKG VKS PWC was selected to produce human MINPP anti-peptide polyclonal antibodies. This custom made anti-peptide antibody was affinity purified using the original peptide antigen fr om Fabgennix, Inc. This antibody was able to immunoprecipitate and recognizes an approximately 58 KDa protein on Western blots using bacteria (E. coli), yeast (Saccharomyces cerevisae), tissues from rat liver and kidney, expressing MINPP. Also, the immunoprecipitated proteins from rat liver cell lysates as well as rat liver and kidney microsomal preparations displayed MINPP enzyme activity as determined by hydrolysis and separation of radiolabelled inositol phosphates by anion exchange column chromatography. To further elucidate the physiological role of MINPP, we studied the putative protein-protein interactions between the MINPP and the heat shock protein 40 (HSP40). Our co-immunoprecipitation experiments suggest that there is an association between MINPP and HSP40.

30.  Binding and Recognition of Bacillus cereus by Dictyostelium discoideum Using Glycoconjugates

Rasol, Aveen; Tevebaugh, Whitney; Bush, John, Tarasenko, Olga

University of Arkansas at Little Rock

Dictyostelium discoideum is a non-pathogenic soil-living amoeba that shares its environment with Bacillus cereus, a food contaminant known to cause gastrointestinal illness in humans. It is possible that D. discoideum consumes B. cereus in soil, and that the natural rate of consumption can be increased by modifying bacterial spores. Glycoconjugates (GCs) are carbohydrates covalently attached to other chemical molecules. It has been shown that GCs are involved in recognition and binding of phagocytic cells to labeled targets. The present study analyzes binding affinity of GCs toward B. cereus spores and assesses which GC is most efficient in stimulating D. discoideum to bind and recognize GC-bound spores. GC9 and GC10 have the highest binding affinity to B. cereus, while GC1 and GC2 have the lowest. GC9 and GC10 were used to test binding and recognition of B.cereus spores by D. discoideum. Since the amoeba undergoes radical metabolic change du ring food shortage, binding and recognition were tested under starving and non-starving conditions at 4°C and 25°C. GC10, relative to GC9, was found to enhance binding and recognition of B. cereus spores by D. discoideum under the non-starving condition at both temperatures, while the difference between the two GCs under the starving condition at both temperatures was small. Our results suggest GCs and D. discoideum can be used to eliminate contamination by B. cereus spores.

31.  Linkages between Parental Nutrition and Health Knowledge, and Childhood Obesity

Boumtje, Pierre I.¹; Huang, Chung L.²; Lee, Jonq-Ying³; Lin, Biing-Hwan⁴

¹Southern Arkansas University

²University of Georgia

³University of Florida

⁴US Department of Agriculture

We use switching regression methods and data from the United States Department of Agriculture (USDA) Continuing Survey of Food Intakes by Individuals (CSFII) to establish links between parental nutrition and health knowledge, and the development of obesity among school-age children in the US. Results suggest parental nutrition and health knowledge, food consumption patterns, demographics, and socioeconomic factors significantly impact children weight status. The results also provide important policy implications to public health officials with respect to the development of nutritional education and information delivery.

32.  Knockdown of COG complex proteins affects glycosylation and retrograde tethering

Smith, Richard D.¹; Morelle, Wille²; Lupashin, Vladimir¹

¹University of Arkansas for Medical Sciences

²University of Lille, France

The COG complex is a hetero-octomeric complex (composed of Cog1-8 proteins) that is a retrograde tethering factor responsible for the localization of the different glycosylation enzymes within the Golgi apparatus. Mutations of subunits of the COG complex in humans cause a type II Congenital Disorder of Glycosylation (CDG). Using siRNA-induced knockdowns, we have depleted HeLa cells of the different COG subunits. All of the COG subunit depletions display differential staining of the plasma membrane with lectins compared to control cells indicating disglycosylation. Furthermore, there is also a decrease in the number of N-linked glycans for COG subunit knockdowns compared to controls cells using MALDI-TOF. Application of Brefeldin A (BFA) causes Golgi markers to redistribute back to the ER while COG subunit depletions are defective in the BFA-induced Golgi marker redistribution to the ER. All of these COG complex knockdowns display similar features to COG mutant fibroblasts. Using the siRNA-induced knockdown of COG complex subunits, this lab can generate siRNA-induced CDG.

 

33.  A survey for Entamoeba from invertebrate hosts: increasing molecular data for the assessment of evolutionary history

Chang, Helen; Silberman, Jeffery D.

University of Arkansas

The genus Entamoeba is composed of anaerobic, unicellular, amoeboid eukaryotes. Though there are a few species that are described as free-living, Entamoebae primarily live as parasites in the intestinal tracts of animals. Historically, Entamoebae were studied and classified by their morphological characteristics, but the apparent simplicity of the organisms’ cellular anatomy renders this method insufficient for inferring a fully researched phylogeny, which is necessary for understanding the relationships between the species. Comparative DNA sequence analysis is likely the most powerful method for determining the relationships between Entamoeba species. But to date, the sequence data that is available is limited to that of a few vertebrate-infecting parasites. Therefore, this project focused on increasing the amount of molecular data available by surveying for Entamoeba in suspected insect hosts and studying variation within the genus based on differences between genetic sequences. DNA was extracted from a variety of insect gut contents, and the small subunit of the ribosomal RNA gene was amplified using polymerase chain reaction (PCR) with primers that are specific for the genus and sequenced. When the sequences were compared with other parasitic and free-living species, the Entamoebae that infected insect hosts were found to form a novel monophyletic group. It was discovered that insects not only provided a rich habitat for Entamoebae, they may harbor a rich biodiversity comparable to vertebrate hosts. This data shows that further research should be conducted with a wider selection of insects as well as those animals that feed on them to better understand the relationship of the host to species variation and the evolutionary history of Entamoeba as a whole.

34.  Strategies to document diversity of water mites (Acari: Hydrachnidiae) from the Interior Highlands and facilitate their inclusion in freshwater conservation efforts and ecological research

Radwell, Andrea J.

University of Arkansas

Water mites are the most abundant and diverse group of arachnids in freshwater ecosystems, but they are among the invertebrate taxa that have received relatively little attention. I will (1) describe their ecological role as parasites and predators of many insect taxa and their importance as indicators of freshwater ecological integrity, (2) provide an overview of the current status of knowledge of the diversity of water mites in North America with emphasis on the importance of the Interior Highlands as a refugium for water mite populations during Pleistocene glaciation, and (3) present strategies to overcome the bottleneck that precludes water mites from biodiversity surveys and biogeographic studies, conservations efforts, and ecological research. Finally, I will report on new species descriptions from the Interior Highlands based on traditional morphological taxonomy and information from cytochrome oxidase subunit 1 (CO1) gene sequences.

35.  Fire affects food availability for birds: the response of leaf litter arthropods to woodland restoration in the Ozark Mountains

McClung, Maureen R.; Smith, Kimberly G.

University of Arkansas

Areas of upland oak-hickory forest in the Ozarks are currently being restored to oak woodlands via thinning and burning treatments. Changes in forest structure from restoration have been linked with changes in breeding bird populations, however few studies focus on the link between restoration and food, for example leaf litter arthropods. We investigated the response of breeding bird and leaf litter arthropod populations to oak woodland restoration by comparing populations between units thinned and burned twice (2004 and 2007) and control areas not subjected to restoration treatments. Surveys were conducted May through June in 2009 using distance sampling methods. Bird and arthropod species richness values were similar between control and restored sites; however, species composition shifted. In recently restored areas, ground-foraging birds had lower densities or were absent, e.g. Ovenbirds. The arthropod orders Acari, Coleoptera, and Hymenopter a decreased in abundance in restored sites, while Collembola increased in abundance. Leaf litter biomass, but not arthropod biomass, was lower in restored sites. Results indicate that when assessing how woodland restoration affects bird populations, both habitat structure and food availability should be considered.

 

36. Acute effects of atrazine and nitrate on Hyalella azteca (Amphipoda) in laboratory exposures

Pandey, Ram B.; Warren, Laurie; Adams, Ginny

University of Central Arkansas

Pesticides and other chemical contaminants rarely occur in the environment as single compounds but rather as mixtures. Atrazine is one of the most commonly detected herbicides found in mixtures with other contaminants such as nitrates. Atrazine application in agricultural areas often coincides with fertilizer use, resulting in the presence of both atrazine and nitrate in surface and groundwaters. Atrazine toxicity data are available for many organisms but combined effects of atrazine and nitrate have not been investigated with any invertebrates. This study examined combined effects of atrazine and nitrate with the freshwater amphipod Hyalella azteca using survival as the toxic endpoint. The results obtained in laboratory exposures reveal that atrazine does not alter the toxicity of nitrate. The 96-hour LC50 (concentration that kills 50% of organisms) values with and without the presence of atrazine are 69.8 and 87.2 mg/L NO3-N respectively. Post -test growth and behavioral observations (10-day period) conducted with adult H. azteca following 96-hour exposure suggest that nitrate and atrazine at these concentrations do not result in long-term effects on H. azteca under our experimental conditions.

37.  Acquisition of Immunity to the protozoan Parasite Eimeria adenoeides in Turkey poults and the peripheral Blood Leukocyte response to a primary infection

Gadde, Ujvala Deepthi; Chapman, Hilary D.; Rathinam, Thilkar; Erf, Gisela F.

University of Arkansas

Coccidiosis is a widespread disease of the intestinal tract of turkeys. One of the most common species in the turkey is E.adenoeides. The objective of this study was to investigate the acquisition of immunity to E.adenoeides in turkey poults. A primary infection of 12.5 × 103 oocysts, given to 20 d old poults, resulted in depression of weight gain, and the production of large numbers of oocysts in the feces. Poults were raised under conditions to prevent re-infection to determine the ability of the primary infection to confer protective immunity against a challenge infection of 5 × 104 oocysts given at 34 d of age. Using weight gain and oocyst production following challenge as criteria for protection, the results indicated that immunity had developed. The concentration and proportions among white blood cell (WBC) in peripheral blood were determined at different times following the primary infection. The WBC concentration of infected poults was elevated on d 7 and 11, primarily due to elevated levels of lymphocytes and monocytes on d 7, and eosinophils on day 11. There were no differences in heterophil and basophil concentrations. With the exception of increased percentages of eosinophils on d 11, infection was not associated with alterations in the proportions among WBC populations. Comparison of CD4 and CD8 defined lymphocyte subpopulations in the blood of infected revealed higher concentrations of CD4+ lymphocytes on d 11, lower concentrations of CD8+ cells on day 4, and higher concentrations of CD8+ cells on d 11, as well as elevated ratios of CD4+ and CD8+ lymphocytes in infected birds on d 4 and 11. These alterations in WBC profiles suggest initiation of both innate and adaptive cellular immune activities designed to effectively cope with a parasitic, intracellular pathogen.

38.  Bacterial Responses to Diurnal Processes in Lake Maumelle

Stites, Courtney E., Robinson, Amelia C.; Payne, Forrest E.; Johnson, Dawn; Sweeney, Sharon; Shry, Sam

University of Arkansas at Little Rock

Lake Maumelle is a drinking water reservoir that serves ~400,000 people in the Little Rock-North Little Rock Metropolitan area in Arkansas. Aqueous inorganic and organic chemical and biological profiles were completed at 1 meter intervals every 4 hours over a 24 hour period. The site was selected because of the potential sensitivity to diurnal changes, while remaining representative of the reservoir dynamics. Biological samples were collected for bacteria counts as well as phytoplankton, zooplankton, and bacterial populations. Geochemical parameters were combined to decipher the relationship between aqueous chemistry and the biological response as a function of time of day Bacterial compositions and abundance may provide evidence for biological responses to water chemistry changes. Observed bimodal bacterial counts corresponded to periods (5-9 PM) of high and low dissolved oxygen, whereas morning to early afternoon data indicated a decline in populations adapted to low dissolved oxygen conditions. Preferential functionality of aerobic and anaerobic bacteria responds to diurnal events, with a bias toward heterotrophic processes becoming dominant once autotrophic bacterial activity declined. Bacterial distributions and preferences inferred from geochemical trends and confirmed via culturing may elucidate the relative significance of biological versus physical processes in the lake over a diurnal cycle.

 

 

39.  Stand conditions immediately following a restoration harvest in an old-growth pine-hardwood remnant

 

Bragg, Don C.

USDA Forest Service

 

The Levi Wilcoxon Demonstration Forest (LWDF), a privately owned parcel of old-growth pine-hardwood timber in Ashley County, Arkansas, recently experienced a timber harvest to restore conditions similar to the virgin forest of this region. Following a hardwood-only cut, a post-harvest inventory showed that the number of tree species in the sample area declined from 24 in 2006 (the most recent pre-harvest inventory) to 12 in 2009, with loblolly (Pinus taeda L.) and shortleaf (Pinus echinata Mill.) pine now comprising 59.2% of the remaining live trees, up from 16.2% in 2006. Between 2006 and 2009, overall stand density dropped from 28.2 m2/ha of basal area and 349.2 stems/ha to 16.4 m2/ha and 72.4 stems/ha, respectively. Total live biomass also fell from 224.8 Mg/ha in 2006 to 130.1 Mg/ha in 2009. While most of the pines in the LWDF are between 100 and 200 years old, a ring count sample of 102 randomly selected hardwood stumps yielded only one greater than 100 years old. Two-thirds of these hardwoods were less than 70 years old, having originated after the stand was set-aside by the Crossett Lumber Company in 1939. Historical documentation and recent research suggests that the LWDF is now more comparable to presettlement pine-dominated forests of southern Arkansas, which generally had lower stocking and fewer hardwoods.

 

 

40.  Yucca (Agavaceae) in Arkansas

 

Johnson, George P.

Arkansas Tech University

 

Yucca (Agavaceae; yucca, Spanish bayonet, soapweed) is a genus of shrubs and small trees of North America and the Carribean. Although typically thought of as plants of the American and Mexican deserts, yuccas are widely distributed in the western, eastern and southeastern United States. While the genus is easily recognized by a suite of vegetative and reproductive characters, identification to species is often problematic, both in Arkansas and beyond. Variability in plants may be both from intrinsic (heteroblastic, ecophenic) and extrinsic (hybridization, introgression) sources that cloud species boundaries. Four taxa are now known from the State, two native (Y. arkansana Trel. and Y. louisianensis Trel.) and two introduced escapes from cultivation (Y. filamentosa L. and Y. flaccida Haw.). Yucca arkansana is widely distributed in Arkansas, and is a plant of rock outcrops, dry hillsides and prairie remnants. Yucca louisianensis has a restricted distribution in the State, and is restricted to the sandhills region of southern and southwestern Arkansas. Of our two non-native taxa, Y. flaccida is the most common; both Y. flaccida and Y. filamentosa occur sporadically over the State and occur in areas where cultivation is not apparent. To increase the likelihood of successful identification, collections should be made from flowering plants and digital photos of whole plants and flowers, including pistils, should be included with traditional pressed specimens. If possible, fruiting specimens should be collected later in the year.

 

 

41.  Carbon market impacts on Arkansas’s pine forests

Pelkki, Matthew H.

University of Arkansas at Monticello

In an effort to reduce carbon dioxide emissions in the United States, Congress has authorized a voluntary carbon market though the Chicago Climate Exchange which is effective through the end of 2010. Congress is currently considering a mandatory “cap and trade” market to regulate US carbon emissions. One of the mechanisms that will assist firms in maintaining carbon emission goals is the creation of forest-based carbon offsets. This study considered the effects of such carbon offsets at various price levels by profit-maximizing landowners in southern pine forests in Arkansas. Using actual forest data for young loblolly pine (Pinus taeda, L.) plantations, growth and stand development was modeled using the Forest Vegetation Simulator (FVS), an individual-tree growth model developed by the United States Forest Service. FVS was used to project pine plantations under a variety of management regimes designed to produce high levels of traditional wood products and sequestered carbon. Then, using projected carbon offset and wood product prices, the financial optimal behavior of landowners can be judged. Results from the study indicate that at prices below $8 per metric ton of CO2 do not significantly affect forest production, but do increase forest land values and economic returns to landowners. At prices above $8 per metric ton, forest production shifts from traditional wood products and landowner returns are increased by management strategies that increase sequestered carbon held in forests. Sawtimber production is reduced and forest densities increase substantially. These results are important as Arkansas is the 4th largest producer of softwood lumber and increased forest densities could be detrimental to forest health.

42.  The CRABS CLAW (CRC) gene tree: a phylogenetic analysis of the Eudicots

Narula, Nitish; Krosnick, Shawn

Southern Arkansas University

The CRABS CLAW (CRC) gene is a putative transcription factor responsible for the development of carpels and nectaries in the Eudicot lineage of flowering plants. In this study, we are working to develop a cladogram, or evolutionary tree, that maps the diversification of the CRC gene through time. We are focusing on the various orthologs of the gene across many species including Quercus, Gossypium, Arabidopsis and Passiflora. Recent research has shown that CRC has duplicated in certain lineages of the Eudicots (e.g. Populus, Passiflora, Nicotiana). It has been hypothesized that these different copies of CRC may have acquired additional roles in gene regulation. Phylogenetic analyses presented here indicate that multiple independent duplications have occurred in CRC, as opposed to one ancestral duplication that has been lost in individual lineages over time.

43.  What is a Nectary?

Krosnick, Shawn E.

Southern Arkansas University

Passiflora is a diverse genus consisting of more than 520 species of vines, lianas and small trees. The group displays remarkable variation in floral and vegetative features, even among closely related species. A key characteristic of the genus is the presence of complex nectaries throughout the plant. These nectaries encourage pollination, deter herbivores, and attract bodyguards. Floral and extrafloral nectaries are present on all species of Passiflora within flowers, on floral bracts, stipules, petioles, on leaf margins, and abaxial leaf surfaces. In Passiflora, the position, shape, size, and arrangement of nectaries is so variable that homology assessment among the different nectary classes is difficult. As nectaries likely represent a key morphological innovation for the genus, the need for clear statements of homology among the different nectary classes is great. CRABS CLAW (CRC) has been identified as a key component in the regulation of nectary expression in the core eudicots, and thus represents a strong candidate gene for use in examining the homology among the nectaries of Passiflora. While CRC is not the only gene involved in regulation of nectary expression, it is an integral component and should thus be under strong functional selection within the nectaries of Passiflora. Preliminary data indicate that CRC is present in Passifloraas a single copy, similar to other angiosperms. RT-PCR analysis demonstrated CRC expression in the nectaries of Passiflora. Semi-quantitative RT-PCR analyses were also performed to provide an indication of the overall levels of CRC across floral and vegetative tissues during all stages of development. These data suggest that CRC will be useful in homology assessment among the different nectary classes, thus allowing the opportunity to examine evolution of nectaries across Passiflora.

44.  Second Year of a Multi-year Study of the Effects of Varying Crop Production Treatments on Water and Sediment Quality

Little, J. R.¹; Sappington, D. E.²; Brueggen, T. R.²; Bouldin, J. L.²

¹College of the Ozarks

²Arkansas State University

Studies continue to measure the benefits of conservation tillage and cover crops as Best Management Practices (BMP) on production land. Reducing non-point source contamination originating from agricultural land improves water quality in receiving streams adjacent to row-crop farming. A split-plot design was used with three replicates each of conservation tillage (NT), conventional tillage (T), and cover cropping (CC). Chemical and physical analyses were performed comparing the treatments and laboratory bioassays were also performed using Ceriodaphnia dubia, Pimephales promelas, and Chironomus dilutus as bioindicators of water and sediment quality following EPA methods. In this second year of our study, results confirm that cover cropping reduced the total suspended solids carried in runoff and a negative correlation between turbidity and C. dubia reproduction was measured. Conventional tillage also reduced the amount of sediments carried in run -off, but was not as effective as cover cropping.

45.  Evolutionary history of sexual and apomictic Erigeron tenuis (Asteraceae)

Groff, Dulcinea; Noyes, Richard D.

University of Central Arkansas

The evolutionary relationships of sexual diploid and apomictic polyploid populations of Erigeron tenuis was studied. Erigeron tenuis is the presumed sister species to E. strigosus and it comprises diploid and polyploid populations. Phylogenetic analysis was conducted using sequence from the ITS and ETS spacer regions of nuclear ribosomal DNA (nrDNA). The phylogenetic analysis nests E. tenuis within E. strigosus, which implies that E. strigosus is paraphyletic. Cloning of polymorphic ITS and ETS spacer regions reveals sexual E. strigosus and an unknown sexual progenitor may have contributed to the hybrid origin of apomictic polyploid E. tenuis. This result has implications for our understanding of apomixis in the group.

46.  Arabidopsis Development in Low Atmospheric Pressure

Taylor, James G.; Leonard, Mark

Ouachita Baptist University

In order to prepare for future space missons which will incorporate plants in bioregenerative life support systems operating at low atmospheric pressures, methods and equipment were developed to study Arabidopsis Development in low pressure environments. A hypobaric chamber with internal L.E.D. lighting was hooked up to a vacuum pump and drawn down to 50% atmospheric pressure. Germinated Arabidopsis plants matured inside the chamber over a four day period, and were compared with the control group based on four criteria: root length, hypocotyl length, leaf area, and leaf angle. Results indicated no effects of hypoxia based on the criteria mentioned, though DNA analysis is pending at the time of this paper which may reveal expression of hypoxia activated genes. Reduced hypocotyl length may have indicated dehydration caused by increased evaporative pressure inside the chamber. Experimental plants also developed significantly larger leaf areas than the control plants, contrary to previous research which found thickening of leaves as a response to hypobaria. These results indicate early development of Arabidopsis is not significantly compromised morphoogically when grown at 50% of atmospheric pressure.

 

 

Chemistry Talks

 

1.     Aerosol and Ozone Impacts on Climate: Agricultural and Biogenic Feedbacks

 

Gaffney, Jeffrey S.; Marley, Nancy A.

University of Arkansas at Little Rock

 

Well recognized greenhouse gases such as carbon dioxide, nitrous oxide, and methane, and other radiatively important gases are important in climate forcing and are particular concern from rice production. However, these gases are not the only radiatively important species, as aerosols and tropospheric ozone are also important in climate change. Most scientists will recognize aerosols and ozone as air quality issues in urban areas, but are not as aware of their impacts as climate forcing agents. Carbonaceous aerosols are increasing in importance especially from biogenic sources including agricultural burning. The impacts of greenhouse species including aerosols will be overviewed, and discussed in light of recent work using carbon isotopic measurements (13C and 14C) to examine the potential impacts of biogenic aerosols on climate. Examples from Mexico City and surrounding areas will be presented showing grass fire impacts, and data taken from th e UALR Atmospheric Observatory will be highlighted indicating the importance of biogenic emissions impacting climate as absorbing species. The potential uses of natural isotopic carbon variations (13C and 14C) along with optical characterizations will be presented as a means of examining the impacts of this type of burning practice, specifically for corn and sugar cane (C4-plants). This research was supported by the Office of Science (BER), U.S. Dept. of Energy, Atmospheric Systems Research Program under Grant No. DE-FG02-07ER64328.

 

 

2.     The University of Arkansas at Little Rock (UALR) Atmospheric Observatory

Marley, Nancy A.; Gaffney, Jeffrey S.

University of Arkansas at Little Rock

Atmospheric aerosols and oxidants are at the heart of climate change and air quality issues currently facing the nation on urban, regional, and global scales. An overview will be presented describing the UALR Atmospheric Observatory that has been established to collect data on atmospheric aerosols and gases relevant to climate and air quality. The site is operating from the roof top of the Science Lab Building at UALR with instrumentation on the roof and also in a laboratory located in side SCLB directly below the sampling lines. Description of the various instruments will be given including those used for determination of real time optical properties (scattering and absorption) as well as high volume samplers used for obtaining size-fractionated samples. Other laboratory capabilities at UALR will be described including gamma counting, XRF capabilities, and state of the art UV-VIS-NIR and FTIR instrumentation used for characterizing optical and chemical properties of aerosols. Meteorological measurements as well as precipitation collectors and radiation detectors will also be described along with some examples of data obtained to date that indicate significant influence of biogenic emissions in the Little Rock area on aerosol optical properties. This research was supported by the Office of Science (BER), U.S. Dept. of Energy, Atmospheric Systems Research Program under Grant No. DE-FG02-07ER64327.

3.     Computational modeling of metal hydrides for use in hydrogen storage

Griffin, William O.; Darsey, Jerome A.

University of Arkansas at Little Rock

Metal hydrides are useful for mobile storage of hydrogen in a manner that is safe, compact, and inexpensive. We investigate metals that are candidates to efficiently store enough hydrogen to compete energetically with fossil fuels. Artificial neural networks are a means to find novel relationships between bulk properties and density functional theory (DFT) computational modeling of materials. We utilize from the DFT model the highest occupied molecular orbital, lowest unoccupied molecular orbital, nuclear repulsion energy, total energy, and other properties in order to make predictions of a bulk property such as, the percent weight of hydrogen that the metal hydride will absorb/adsorb reversibly.

4.     Spectroscopic Characteristization and Catalytic Oxidation Studies of a Fe Complex of Tetraamidomacrocyclic Ligand

Sullivan, Shane Z.¹; Ghosh, Anindya¹; Pulla, Sharon¹; Pierce, Bradley S.²; Schnackenberg, Laura³

¹University of Arkansas at Little Rock

²University of Texas, Arlington

³National Center for Toxicological Research

This work presents the spectroscopic characteristization and catalytic investigation of a Fe(III)-complex of a teraamidonmacrylic ligand (1,15,15-Dimethyl-5,8,13,17-tetrahydo-5,8,13,17-tetraaza-dibenxo[a,g]cyclotridecene-6,7,14,16-tetraone). ESI-MS of Fe(III)-complex shows characteristic peak at 418 m/z and isotopic distribution matches well with the theoretically predicted mass spectrum. The rhombic signal with g-values of 4.67, 4.18. and 1.88 was recorded for Fe(III)-complex using EPR study. EPR spectra of Fe(III)-complex shows signals consistent with a ferric iron in an intermediate axial-ligand field, S = 3/2. The S = 3/2 spin-state observed for 2 is further confirmed with the value for magnetic moment (mu eff) determined by the Gouy method. Cyclic voltammetry of Fe(III)-complex in acetonitrile shows two peaks respectively at E1/2 = 0.64 V (Dep = 63 mV) and E1/2 = 0.84 V (Dep = 77 mV) vs Ag/AgCl electrode. From the spectroscopic analysis it was concluded that the complex 2 is a pentacoordinate species comprising of 4 deprotonated nitrogen atoms and an axial ligand which is presumably a water molecule. Fe(III)-complex was found to be soluble in water and activates hydrogen peroxide under ambient conditions. Hydrogen peroxide based rapid catalytic decolorization of water-soluble dyes, pulp and paper effluent bleaching (52% color removal using 6 mg catalyst/L effluent at pH 9.5), and N-oxide syntheses using corresponding amines with as high turnover number as 1034 and yield up to 100% using Fe(III)-complex have been discussed. Oxidation reactions were carried out in the presence of a low concentration of catalyst (0.5 muM) and H2O2. Even though Fe(III)-complex is stable under ambient conditions rapid demetallation occurs in aqueous solution were observed, particularly at 90 degrees Celcius as indicated by UV/Vis spectroscopy.

5.     Oxidation of alcohols to aldehydes using environmentally benign Iron(III) and Copper-amide complexes

Pulla, Sharon; Ghosh, Anindya; Sullivan, Shane Z.

University of Arkansas at Little Rock

The oxidation of alcohol to aldehydes is an important and frequently used transformation in organic synthesis. Environmentally friendly aqueous organometallic catalysis has been developed using efficient catalytic systems composed of Iron and Copper complexes of amide based ligands. Tert-butyl hydroperoxide (TBHP) and hydrogen peroxide (H2O2) have been used as primary oxidants for the oxidation reactions. The product, aldehydes were detected and quantified using standard Gas Chromatography Mass Spectrometer technique. Under the reaction conditions no carboxylic acid was detected indicating the selectivity for the catalytic systems. The catalyst which operates in water and under relatively mild conditions can be separated easily and reused for further reactions.

6.     Molecular Modeling studies of Geldanamycin and its derivatives to treat Parkinson’s Disease

Thotakura, Sushma; Darsey, Jerry

University of Arkansas at Little Rock

Parkinson’s disease (PD) is a neurodegenerative disorder associated with progressive loss of dopaminergic neurons in substantia nigra of the brain. Parkinson’s treatment on the molecular level involves the removal of the insoluble protein lumps called the ‘Lewy bodies’ formed by the mis-fold of certain proteins like alpha-synuclein. Heat shock proteins (HSPs) are the major molecular chaperones that mediate the proper folding of proteins like alpha-synuclein and help them maintain their native confirmation during conditions of stress preventing them from forming aggregates. Geldanamycin (GD) binds to and inhibits the molecular chaperone Hsp90 inducing the production of Hsp70 which prevents neurotoxicity by facilitating the refolding of mis-folded proteins. An Artificial Neural Network (ANN) was trained using, orbital energies of the 20 Lowest Unoccupied and 20 Highest Occupied Molecular Orbitals and dipole moments all as inputs and, the I C50 (concentration of a drug that is required for 50% inhibition) values for GD and its derivatives as the outputs. Once the ANN was trained, derivatives of GD whose IC50 values have not been determined experimentally were used as test compounds. The IC50 values of these test compounds were predicted using the ANN. This will give us an idea about their inhibitory activity, and will reduce the number of molecules that need to be synthesized, reducing the experimental costs incurred to carry out high throughput screening assays to identify potential inhibitors of Hsp90.

7.     Platinum nanorod arrays with enhanced electrocatalytic activity for oxygen reduction reaction

Khudhayerm, Wisam J.; Shaikh, Ali U.; Karabacak, Tansel

University of Arkansas at Little Rock

Vertically aligned platinum (Pt) nanorod arrays produced by glancing angle deposition technique (GLAD) have been investigated for their electrochemical properties as a potential cathode material in polymer electrolyte membrane (PEM) fuel cells. These single-layer and single-crystal catalyst nanorods without any carbon support have been produced at lengths varying between 20-600 nm, which correspond to Pt weight loadings as low as 16-500 μg/cm2. GLAD nanorods have been deposited in sputter deposition unit at a glancing angle of 85o as measured from the substrate normal. Electrodes of conventional polycrystalline Pt thin films sputter deposited at normal incidence and commercially available carbon supported Pt nanoparticles (Pt/C) were also prepared to be compared with Pt nanorods for their crystal, morphological, and electrochemical properties. Morphology and crystallographic structure of Pt nanorods have been studied using scanning electron mic roscopy (SEM) and X-ray diffraction (XRD), respectively. SEM results reveal that Pt nanorods are well-isolated, vertically aligned, and single-crystal with atomically sharp tips. The single-crystal property allows enhanced electrochemical activity and reduced surface oxidation, while the isolated nature of the rods in lateral directions can provide a channeled porosity for effective transportation of oxygen or other gases in a PEM fuel cell. Cyclic voltammetry (CV) was performed to characterize the electrochemical activity of` the Pt nanorods as well as the conventional Pt/C and polycrystalline Pt film electrodes. It was revealed that well-defined multiple peaks exist in the CV profiles of Pt nanorods. Multiple CV peaks, which are absent or weak in conventional Pt/C and Pt film electrodes, are due to the electrochemically active preferential crystal plane orientations in Pt nanorods. In addition, enhanced electrochemical activity is also believed to be due to the single cryst al structure of individual nanorods and their resistance to surface oxidation. Pt nanorod electrocatalysts also reduce oxygen to water at a more positive potential than that of the Pt/C, indicating that our catalyst has a lower oxygen overpotential due to the enhanced electrode porosity, single crystal property, and the dominance of the preferred crystal orientation for oxygen reduction reaction (ORR). Finally, a series of CV scans show that our catalyst is more stable than Pt/C in the acidic environment.

 

 

8.     Development of a double-isotope UPLC-MS/MS method for the determination of plasma citrulline concentration

Brown, Joshua D.

University of Arkansas

The bioavailability of citrulline depends on the production of citrulline from other amino acids by enterocytes. The health of enterocytes is greatly affected by radiation common in cancer treatments. Therefore, citrulline may be used as a biomarker for radiation-induced intestinal damage. However, there is no adequate calibration matrix for citrulline since it is an endogenous compound. It was the goal of this project to develop a double isotope, ultra-performance/tandem mass spectrometry (UPLC-MS/MS) method for the determination of plasma citrulline concentrations. Top-spiked plasma samples were treated with various solutions for protein precipitation to observe optimal linearity of samples. Matrix ion effects were studied by post-column infusion of citrulline. Optimized extractions were obtained with 95% acetonitrile (with 0.2% formic acid) and resulting in peak area versus concentration graphs with R2 = 0.9961. Samples were filtered us ing 96-well extraction plate. The contributions of citrulline and citrulline +1 to each other were observed to. determine the proper use of isotopes as the calibration or internal standard. This methodology was used to determine plasma citrulline in mice and rats challenged with escalating doses of radiation.

9.     Sol-Gel Synthesis and Characterization of Iron Titanates

Trujillo, Josh; Klishina, Ekaterina; Hardcastle, Franklin D.

University of Arkansas

For many years, bulk titania (TiO2) has been investigated both as a photocatalyst for the decomposition of organic waste and as a potential water-splitting catalyst for generating hydrogen fuel from water. Recently, iron-doped TiO2 has been investigated for the photocatalytic splitting of water into hydrogen and oxygen using solar light because of its more favorable bandgap compared to pure titania. In the present study, the sol-gel method was used to synthesize iron titanates and iron-doped TiO2 powders and films. Thin films were produced by a dip coating process. Samples were prepared having Fe:Ti molar ratios of 0.25, 0.50, 0.75, 1.00, 1.25, 1.50, 1.75, and 2.00. In the first phase of this study, Raman spectroscopy and X-ray diffraction were used to characterize the resulting iron-titanium phases. Once the films have been characterized, photoelectrochemical (PEC) measurements will be performed to determine photocatalytic activity.

10.  Iron-carbonyl cluster coupled to mercaptobenzothiazole as a mimic of hydrogenase enzymes

Felton, Charlette M.; Mebi, Charles A.

Arkansas Tech University

We are interested in the synthesis and characterization of transition metal carbonyl complexes as models for the active site of hydrogenase enzymes. The model compounds are of interest as catalysts for the production of hydrogen, a clean alternative to fossil fuels. In this study, a new model complex prepared by the reaction of Fe3(CO)12 and mercaptobenzothiazole is described. The complex (1) has been characterized by spectroscopic (UV-vis, IR, and NMR) methods and elemental analysis. The IR spectrum of 1 in CH2Cl2 shows peaks at 2087, 2063, 2042, and 2006 cm-1 corresponding to terminal metal carbonyl ligands. The electrochemical property of compound 1 was investigated by cyclic voltammetry and will be presented. Complex 1 was examined as a catalyst for the electrochemical reduction of proton to molecular hydrogen. Cyclic voltammograms of 1 in the presence of increasing amounts of acetic acid were obtained. The results indicate that compound 1 is effective as an electrocatalyst for the reduction of proton to hydrogen.

11.  A Computational Investigation of Tropane and its Phosphorus Analogue

Crowell, Vernon D.; Grafton, Anthony K.; Pace, R. David

Lyon College

Tropane is a nitrogenous bicyclic compound contained in the biologically active tropane alkaloids. The pyramidalization around the nitrogen gives rise to two important molecular conformations. Interestingly, the less thermodynamically stable conformation is more prone to N-methyl addition in the Menshutkin reaction, ostensibly due to steric effects. To provide a basis for a better understanding of the properties and reactivity of this molecule, the endo and exo conformations of both tropane and its phosphorus analogue were examined computationally. Energy differences between the between the relevant conformations and the barrier to inversion were calculated at the B3LYP, MP2, and Hartree-Fock levels of theory with a variety of basis sets and compared with available experimental data and previous computational work. Additionally, infrared and NMR spectra were predicted to augment ongoing experimental work.

12.  Synthesis and Characterization of Ruthenium Complexes Containing Chloro-Phenanthroline and Bipyridine

Bartlett, Jared; Kudo, Shotaro; Bhuiyan, Anwar A.

Arkansas Tech University

There is an intense interest in designing molecular systems which will absorb visible sunlight, initiate an electron transfer process, and ultimately convert the solar energy to useful chemical energy (such as hydrogen from water). The divalent ruthenium polypyridine complexes hold promise as efficient photocatalysts for solar energy conversion schemes. This presentation deals with the synthesis and spectroscopic investigation of ruthenium polypyridine complexes which may be useful in the development of solar energy conversion schemes. The homoleptic ruthenium(II) complex Ru(Cl-phen)₃(PF₆)₂ (where Cl-phen = 5-chloro-1,10-phenanthroline), heteroleptic ruthenium(II) complexes Ru(Cl-phen)₂(bpy)(PF₆)₂, and Ru(Cl-phen)(bpy)₂(PF₆)₂ (where bpy = 2,2′-bipyridine) is prepared by following the standard synthetic procedure. The complexes are purified by repeated column chromatography. The identity and the integrity of the complexes are confirmed by elemental analysis as well as mass spectroscopy. UV/Vis absorption, nmr spectroscopy, emission spectroscopic method, and cyclic voltammetric method is used to investigate the properties of these complexes.

13.  Use of Geochemical Proxies to Identify Watershed Inputs to Lake Maumelle, Central Arkansas

Johnson, Dawn M.; Robinson, Amelia C.; Smith, Jena P.; Payne, Forrest E.; McMillan, Margaret E.; Stites, Courtney E.

University of Arkansas at Little Rock

Geochemical characterization of Lake Maumelle, one of the primary drinking water sources for central Arkansas, provides insight into natural and anthropogenic perturbations in the watershed that have impacted its water quality. We used traditional geochemical parameters combined with total organic carbon, aqueous soil-derived metals, and lignin and tannin compositions to track the response of creeks and adjacent coves to land use within Lake Maumelle. Data from six creeks and five corresponding coves were collected throughout the summer to evaluate possible changes in the water quality related to land management. Several geochemical parameters were elevated in creeks without concomitant increases in adjacent coves, suggesting deposition, recycling, or dilution of constituents transported from the watershed. Preliminary results indicate that primary production controls dissolved oxygen levels and organic carbon compositions within coves, wher eas a greater proportion of organic matter in creeks was plant derived. Creeks from parts of the watershed that have been affected by clear-cutting show a two fold increase in silica and plant-derived compounds, compared to relatively protected areas in the northeast and southern portions of the watershed. Cove geochemistry, including silica and iron, is remarkably consistent, despite having contrasting compositions across the different streams sources. From this, it is apparent that some dissolved species are well mixed between coves and the main body of the lake. As such, increased contributions of phenolic plant compounds that are efficiently redistributed throughout the lake may be problematic, given their potential for forming carcinogenic disinfection by-products.

14.  Chemical analyses to determine tributary contribution to the Spring River, AR

Brueggen, Teresa R.¹; Downing, Carolyn B.²; Bouldin, Jennifer L.¹

¹Arkansas State University

²Ball State University

Tributaries and inlets often play an important role in the chemical properties, productivity and species diversity in a receiving river channel. The objective of this study was to analyze the impact of inlets on the water chemistry of the Spring River, AR. The Spring River has an approximate reach of 92 km and was previously divided into four zones according to the water source that fed each zone. In this study approximately 30 km of the upstream river segment were sampled that included nine inlets contributing to the main river channel and incorporated the upper three previously defined zones. Samples were collected from the headwaters located at Mammoth Spring, AR, as well as upstream, within and below the confluence of each inlet with Spring River. Water quality parameters analyzed included pH, dissolved oxygen, conductivity, alkalinity, hardness, total suspended solids, fecal coliform, chlorophyll-a, nutrients (ortho-phosphates, nitrat es, nitrites), and total dissolved ions. Results of total dissolved ions defined the three same zones as before within the sampled reach of the river. Seven of the nine inlets indicated contributions ranging from 3.5 to 66.7% to the mainstream. Results from this study demonstrate the ability to measure tributary contribution to river systems.

 

 

Physics Talks

 

1.     Shock Conditions and Electron Drift Velocity Range

 

Kilbourn, Amanda; Hemmati, Mostafa; Massery, Michael; Bramlett, Rebecca; Childs, William

Arkansas Tech University

 

The process by which a neutral gas is converted into a conducting medium is accomplished by a space charge fluid advancing into an ion-less gas, ionizing the heavy particles and behind the wave, the medium is left as quasi-neutral plasma. For theoretical investigation of breakdown waves, we use a one-dimensional, steady-state, three component fluid model and the set of equations describing the wave is referred to as the electron fluid-dynamical equations. The set of equations consists of the equations of conservation of mass, momentum and energy, plus the Poisson’s equation. In the case of breakdown waves, the wave front is considered to be a shock front and proper shock conditions on electron temperature and velocity are essential for successful solution of the set of equations describing the wave. The shock conditions have also shown to be essential in solving the set of electron fluid dynamical equations for the whole range of experimentally observed breakdown wave speeds. We will present the derivation of the proper set of boundary conditions and application of those conditions in solving our set of electron fluid-dynamical equations.

 

 

2.     Impact of Substrate Temperature on Photovoltaic of CdS/Si Solar Cells Made by Chemical Spray Pyrolysis

Ismail, Radi A.¹; Abdulrazzaq; Omar A.²

¹University of Technology, Baghdad

²University of Arkansas at Little Rock

In this paper, some photovoltaic characteristics namely Open Circuit Voltage, Short Circuit Current, Conversion Efficiency, Minority Carrier Lifetime, Fill Factor and Spectral Responsivity for CdS/Si heterojunction solar cells made by spray pyrolysis technique have been investigated. The dependence of substrate temperature (T_S) within the range 300-500 °C on the photovoltaic characteristics has been studied. Optimum photovoltaic results (Open Circuit Voltage = 460 mV, Short Circuit Current = 42 mA/cm², and Conversion Efficiency = 6.4%) were obtained for T_S = 450° C without using any post-deposition heat treatment or antireflection layer. Deterioration in parameters has been observed for T_S > 450 °C. Stability characteristics of theses cells have been investigated.

3.     Synthesis and Dielectric Measurement of Potassium Sodium Tartrate (KNaC4H4O6·4H2O)

Kendall, Barnett A.; Jones, Tori R.; Crowell, Vernon D.; Hutton, Stuart L.

Lyon College

Potassium sodium tartrate is an example of a ferroelectric crystal known more commonly as Rochelle salt. In our lab, we have synthesized high quality large single crystals of Rochelle salt. By morphological identification of the ferroelectric a-axis and by temperature and frequency dependent ac impedance measurements, our preparation technique has been shown to have properties consistent with expectations of Rochelle salt. A detailed procedure that we developed to efficiently and reliably produce high quality single crystals of potassium sodium tartrate will be presented.

 

 

4.     p-type ZnO Nanowires Doped with Ag by a Low Temperature Electrochemical Process

Thomas, M. Allan; Cui, Jingbiao

University of Arkansas at Little Rock

As a wide band gap semiconductor, ZnO continues to be extensively studied for potential applications in various optoelectronic and electronic devices. To date, ZnO has been prepared in high quality using a multitude of deposition methods across a wide range of growth temperatures. However, a method for producing p-type ZnO in a reliable and repeatable fashion remains to be seen. In this work, Ag-doped ZnO nanowires were obtained by low temperature electrochemical growth in aqueous solution. After a post-growth annealing treatment, doped samples attained under optimal growth conditions become p-type. The p-type conductivity is achievable only when the incorporation of Ag does not significantly affect the quality of the ZnO nanowires. Applied potentials below a critical value of -0.65 V (more negative relative to Ag/AgCl) as well as moderate Ag concentrations during growth are necessary to produce p-type properties in the doped ZnO. In addition, t he conductivity type of the doped ZnO nanowires correlates with their optical properties. p-type ZnO nanowires exhibit a band gap reduction and strong acceptor-related photoluminescence, while n-type nanowires show band gap broadening with a strong donor bound exciton emission. The results indicate that p-type ZnO can be obtained by an economical, low temperature process, opening up possibilities for low-cost, advanced optoelectronic devices based on ZnO nanowires.

5.     Initial Growth Stage of Indium Notride on Si substrate by Plasma-Assisted MOCVD

Norman, Dever P.¹; Hamad, Samir¹; Tu, Li-Wei²; Chiang, Shu-You²; Seo, Hye-Won¹

¹University of Arkansas at Little Rock

²National Sun Yat-Sen University, Taiwan

The growth of Indium Nitride (InN) on n-type Si substrate was achieved without ammonia using nitrogen plasma as sole atomic nitrogen contribution. The SiN buffer layer was used to accommodate the lattice match and thermal strain effects between InN and Si. We varied the growth temperature, III/V ratio, and nitridation condition, for studying the growth kinetics and initial stage growth. SEM images and Photoluminescence spectra were studied to characterize the morphology, structural qualities, and optical properties of InN materials. Effects of the growth parameters along with the growth mechanism will be discussed.

 

 

6.     Fabrication and Characterization of  PrBa₂[Cu_xM_1-x]₃O₇ (x=0.2, Ga, Al) Epitaxial Thin Films 

 

Kandel, Hom¹; Iliev, Milko²;  Bourdo, Shawn¹; Chen, Tar-Pin¹; Seo, Hye-Won¹; Watanabe, Fumiya¹; Wang, SHou-Zheng¹;  Cui, Jing-Biao¹; Vishwanathan, Tito¹

 

¹University of Arkansas at Little Rock

²University of Houston

We have fabricated epitaxial thin films of insulating materials PrBa₂(Cu_1-xM_x)₃O₇ (x=0, 0.2; M= Ga, Al) by Ga and Al substitution for Cu in PrBa₂Cu₃O₇. The electrical resistivity in these materials are many orders higher than in PrBa₂Cu₃O₇ at 77K, which will provide an effective potential barrier to YBa₂Cu₃O₇  in high T_c S-I-S Josephson junction. X-ray diffraction, atomic force microscopy, Raman measurement and temperature dependent resistivity measurements were performed to characterize these thin films. The temperature dependence of the resistivity follows the Mott’s Variable range hopping law ρ= ρ₀ exp (T/T₀) ^-1/4 up to ~105K in PBCO and in PBCMO (M=Ga, Al) at least up to the room temperature. We will discuss the results from Raman spectroscopy and electrical transport studies performed in these insulating materials.

 

 

7.     Biosensor Applications in Biological Sciences and Engineering and Design of a Novel Electrochemical Biosensor for Biodiesel Quality Sensing

 

Hossain, Md. Zakir¹; Shrestha, Dev²; Kleve, Maurice G.¹

¹University of Arkansas at Little Rock

²University of Idaho

 

A biosensor is an analytical device that uses biomaterials as elements of sensing system and converts a biological response into an electrical signal. The aim of this study was to assess the biosensor applications in biological sciences and engineering areas in relation to the world biosensor market. The classifications of biosensors based on their sensing biomaterials, transducers coupled with different levels and the characteristics or parameters of biosensors were discussed. A novel potentiometric lipase biosensor system for free and total glycerol sensing of biodiesel was proposed and discussed in detail. The study ended with a discussion on the future potential uses of biosensors in biological sciences and engineering areas. Key words: Biosensors applications, biodiesel, quality sensing, electrochemical biosensor, biological sciences and engineering.

 

 

8.     Temperature Controlled Nano-indentation of Graphen Sheet

Downs, Roy; Terdalkar, Sachin S.; Rencis, Joseph J.

University of Arkansas

Large-scale molecular dynamics (MD) simulation of nano-indentation of graphene sheet is performed. An Adaptive Intermolecular Reactive Empirical Bond Order (AIREBO) potential is used for the carbon-carbon interaction. The Young’s modulus of graphene is calculated from the load indentation data using the Timoshenko plate theory. The MD simulation results for Young’s modulus of a graphene sheet are compared with experimentally calculated value. MD simulations results were found to be very much similar to the experimental values. Using the thermostat in the MD simulation the effects of temperature variation on the Young’s modulus is studied. This technique will further help us study the migration of point defects in the graphene sheets in presence of thermo-mechanical loading.

9.     Hydrophobic Metallic Nanorods with Teflon Nanopatches

Khudhayer, Wisam J.; Sharma, Rajesh; Karabacak, Tansel

University of Arkansas at Little Rock

Introducing a hydrophobic property to vertically aligned hydrophilic metallic nanorods was investigated experimentally and theoretically. The platinum nanorod arrays were deposited on flat silicon substrates using a sputter glancing angle deposition technique (GLAD). Then a thin layer of Teflon (nanopatch) was partially deposited on the tips of platinum nanorods at a glancing angle of θdep = 85o for different deposition times. Teflon deposition on Pt nanorods at normal incidence (θdep = 0o) was also performed for comparison. Morphology and elemental analysis of Pt/Teflon nanocomposite structures were analyzed using scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDAX), respectively. It was found that GLAD technique is capable of depositing ultrathin isolated Teflon nanostructures on selective regions of nanorod arrays due to the shadowing effect during obliquely incident deposition. Contact angle measurements on nanoco mposite Pt nanorods with Teflon nanopatches exhibited contact angle values as high as 138o, indicating a significant increase in the hydrophobicity of originally hydrophilic Pt nanostructures that had an angle of about 52o. The enhanced hydrophobicity of Pt-nanorods/Teflon-nanopatch composite is attributed to the presence of nanostructured Teflon coating which imparted a low surface energy. Surface energy calculations were performed on Pt nanorods, Teflon thin film, and Pt/Teflon composite using two liquids method to confirm the contact angle measurements. Furthermore, a new contact angle model utilizing Cassie and Baxter theory for heterogeneous surfaces was developed in order to explain the enhanced hydrophobicity of Pt/Teflon nanorods. According to our model, it is predicted that solid-liquid interface is mainly at the Teflon tips when the composite nanorods are in contact with water.

10.  Strain-Mediated Migration of Vacancy Defects in Graphene

Terdalkar, Sachin S.¹; Zhang, Sulin L.²; Rencis, Joseph J.¹

¹University of Arkansas

²Pennsylvania State University

The migration of the double and single vacancy defects in graphene is studied using the climbing image nudged elastic band method. A second generation Tersoff – Brenner potential is used to calculate the minimum energy path for double vacancy defect migrations. The simulations show that upon thermal activation, the double vacancy can be transferred to a Stone-Wales defect through 90° bond rotations. A coupled quantum mechanics – molecular mechanics model is developed to calculate the minimum energy path for single vacancy defect migrations. Simulations show that the transition of single vacancy defects takes place through the series of bond switching mechanisms. The application of mechanical strain considerably alters the energy barriers. Change in the direction of mechanical strain also affects the migration of the vacancy defects. These results will shed light on controlling the defect migration in graphene, thereby giving rise to a fundamental basis on graphene perfecting.

11.  Formation of Nano-Indium (III) Sulfide/Cadmium Telluride Structures by Combined Evaporation and Electrodeposition Processes

Vangilder, Joshua A.¹; Engelken, Robert D.¹; Felizco, Frederick¹; Hall, John¹; Chaudhury, Z.¹; Thapa, S.¹; Karabacak, T.²; Cansizoglu, F.²; Seo, Hye-Won²

¹Arkansas State University

²University of Arkansas at Little Rock

We report on initial research involving formation of p-n junction-like structures from n-type indium (III) sulfide and p-type cadmium telluride. The indium sulfide was deposited by vacuum evaporation methods. Conventional thermal evaporation at ASU and UALR was used to deposit standard amorphous-to-polycrystalline indium sulfide films onto indium tin oxide-coated glass substrates configured parallel to the molybdenum evaporation boat containing the indium sulfide source powder (Cerac-brand). Nanorod-structured indium sulfide films were deposited at UALR by glancing angle deposition (GLAD). With GLAD, the substrates are configured at angles greater than 80o relative to the plane of the boat. It is expected that the aligned nanorod structure will lead to superior optoelectronic performance in subsequent photodiodes and solar cells relative to that of devices based on conventional films. Cadmium telluride is being electrodeposited at ASU onto the indium sulfide/ITO/glass samples by electrodeposition3, with both aqueous and organic plating baths being investigated. The indium sulfide tends to crack and flake in the aqueous baths, so focus has been primarily on organic, for example ethylene glycol, baths of cadmium and tellurium salts such as cadmium chloride and tellurium chloride. P-n junction-like structures are formed by application of conductive contacts such as silver ink, electroless nickel, and evaporated metals onto the cadmium telluride. Various electrical measurements, for example current-voltage analysis, and optical measurements, for example optical absorption and photoconductivity, are being used to characterize the structures. The presentation will report on initial aspects of the study. This work was supported, in part, by a new three-year NASA EPSCoR grant administered through the Arkansas NASA EPSCoR Office/Space Grant Consortium at UALR (Dr. Keith Hudson, Laura Holland, and Sue Hawkins) and sponsored by NASA Marshall Space Flight Center (Dr. Ralph Carruth).

12.  Synthesis of Bismuth (III) Sulfide Nano/Micro Powders from Low Cost/Low hazard Thiosulfate Baths, and Vacuum Evaporation and Spray Deposition of Such

Felizco, Frederick M.; Engelken, Robert D.; Vangilder, Joshua A.; Hall, John; Thapa, Shyam; Chaudhury, Zariff

Arkansas State University

We report on the synthesis of bismuth (III) sulfide powders by chemical precipitation in predominately organic solutions of bismuth salts and thiosulfate ion, as a safer sulfur source alternative to more hazardous thiourea, thioacetamide, and thiolacetic acid. The bath nominally consists of bismuth citrate dissolved in a triethylene glycol/formic acid bath containing trace hydrochloric acid/water to facilitate dissolution of the bismuth citrate. A few drops of a concentrated aqueous solution of sodium thiosulfate are added, followed by mild heating. After a few minutes to a few hours, depending upon temperature, the solution turns brown and a colloidal nano-suspension of bismuth (III) sulfide forms, along with concurrent growth of bismuth (III) sulfide films onto submerged surfaces. Eventually, this powder flocculates sufficiently into the micron size that it can be collected by filtration, multiple washings, and drying. The powders are th en re-pulverized via mortar-and-pestle. We have investigated the potential photosensitivity of these powders, as semiconductors, by depositing subsequent thin films based upon them. The first method is resistive thermal vacuum evaporation from electrical current-powered molybdenum boats at pressures in the 10-5 to 10-4 torr range. The resultant films do evaporate well into uniform and adherent thin films on glass substrates, but sometimes show evidence of contaminant phases. The second method involves compressed gas-driven air brush spraying of the suspended powders, and sometimes additional dissolved organic binder, in an acetone carrier onto printed circuit board substrates with interdigitated metallic contact patterns. Chocolate-brown films are easily formed by the “spray painting” procedure. Photoconductivity measurements are in the process of being conducted. Initial results indicate good photoconductivity in the best cases, but little-to-no photoconductivity in the worst cases, particularly when the colors of the powders and films imply probable contaminant residues from the synthesis solution. Current efforts focus upon optimizing the solution chemistry and powder collection process to eliminate these. The chemistry and process have potential as a way to safely and economically synthesize large quantities low toxicity/low environmental impact semiconductor-grade bismuth (III) sulfide powders for large scale optoelectronic applications.

 

13.  Muon and Gamma Ray Detection

Bachri, Abdel G.¹; Goldschmidt, Azriel²; Taylor, Amanda³

¹Southern Arkansas University

²Lawrence Berkeley National Laboratory

³Oklahoma State University

Galactic cosmic radiation continually bombards Earth’s surface as they come from unknown origins. This radiation is composed of high-energy proton streams that interact with atmospheric particle and burst into showers of photons and smaller charged particles, such as Muons. We modified the Lawrence Berkeley National Laboratory cosmic ray detector to create a versatile and portable muon and an efficient gamma ray detector. The detector used scintillation to transform radiation into detectable light photons that were directed toward a photomultiplier tube (PMT) surface, triggering photoelectrons, which were then amplified to yield measurable electronic pulses. Two modules were connected to an electronics section that compared two signals and logically determined if they were coincidence counts. A Data Acquisition board converted these pulses into counts per minute to determine the radiation flux. The two detection modules were mounted on a solid frame allowing for various configurations between the two scintillators. Positioning the detector in different arrangements, the group measured cosmic ray muon flux as it varied with altitude and angle as dictated by detector orientation toward the sky. We found that more muons were detected at higher altitudes and at angles around 75° from the horizontal. After muon detection, and with the added capacity to detect gamma rays, experiments with Sodium-22 and Cobalt-60 as gamma radiation sources allowed the group to study the effects of distance and shielding. Inverse square law predicted radiation flux to be proportional to the square of the distance from a point source; with the detector arranged in different configurations of the scintillator modules, our results closely validated the attenuation of radiation as 1/r2. The effectiveness of shielding was also investigated. Experimentation using the different types of radiation reflected expected values and ensured the functi onality of the modified detector.

14.  Building a Cosmic Ray Detector

Grant, Perry¹; Bachri, Abdel¹; Goldschmidt, Azriel²

¹Southern Arkansas University

²Lawrence Berekely National Laboratory

The Lawrence Berkeley National Laboratory (LBNL) Quarknet Cosmic Ray (CR) detector originally constructed in 2002 only studied CR Muons. The ability of the LBNL Quarknet CR detector to detect Gamma Rays from a radioactive source is accomplished by adapting the detector to increase its efficiency. Each detector module used 1” thick scintillator attached to a photomultiplier (PMT) and mounted to an aluminum and plastic frame. Two modules were connected to an electronics section that compared the signals from the modules and logically determined if they were coincidence counts. A data collection device was added to upgrade the ability to count for hours or days and for faster count rates. Count rates were taken at a variety of distances from the radioactive source 60Co (Cobalt) that produced two Gamma Rays and a Beta particle. Further, two modules were adjusted to different angles of rotation from each other and the coincidence counts measu red. CR measurements were taken at different angles to determine the Muon flux as the angle from vertical decreased. The results showed the number of counts decreased as a function of increasing distance from the source. The coincidence counts from the modules set at various angles was consistent throughout the angular spectrum and only lead shielding visibly reduced the number of counts from the radioactive source. The Muon flux decreases as the angle from vertical get closer to the horizon, suggesting that since the Muons have to travel farther through the atmosphere more of them decay. The conclusion from these experiments is that the LBNL Quarknet CR detector can be adapted to test for Gamma radiation. This experiment demonstrates that the Quarknet project can be opened up to include not only Cosmic Rays but also Gamma Rays.

15.  Radiation Flux Variation with Solid Angle

Cuevas, Noe¹; Bachri, Abdel¹; Goldschmidt, Azriel²

¹Southern Arkansas University

²Lawrence Berkeley National Laboratory

Muons and Gamma Rays (GR) were detected with the updated Lawrence Berkeley National Laboratory Cosmic Ray Detector. When these particles traversed the two synchronized EJ-212 Plastic Scintillators, two photo multiplier tubes (PMT) generated pulses which were counted by a Data Acquisition board (DAQ). Each PMT had an optimum control voltage; therefore the Detector had to be adjusted to achieve the highest count rate without background noise. Because muons are the product of collisions between high energy cosmic rays and atmospheric nuclei, and therefore shower on earth, the scintillators were arranged vertically for detection [1]. For the detection of Gamma Rays (GR), a radioactive Sodium-22 sealed source was placed between the two horizontally arranged scintillator detectors. The amount of “hits” by these particles was determined by the solid angle (Ω) yielded from the distance between the midpoint and sealed source to the scintillators. Th e solid angle essentially represented the angle and direction of the particle flux; therefore there was a linear correlation between the “coincidence” counts and the solid angle. Consequently, the flux of the particles was determined as a function of distance between the scintillators. The data was recorded at different locations; at the laboratory (800ft), at Mt. Diablo (3800 ft) and at the Berkeley Marina (100 ft). The flux dependence on the distance between the scintillators was consistent at these altitudes.

16.  Thermalization and memory effect in relativistic heavy ion collisions

Zhang, Bin; Wortman, Warner A.

Arkansas State University

The Quark-Gluon Plasma is thought to have existed in the early universe. People are now using relativistic heavy ion collisions to create the Quark-Gluon Plasma in terrestrial laboratories. This provides an opportunity to study matter under extreme conditions similar to those in the early universe. The Quark-Gluon Plasma is produced from collisions of heavy nuclei out of equilibrium and how it equilibrates is important for the extraction of its properties. We use a radiative transport model to study the thermalization and equilibration of the Quark-Gluon Plasma. Different initial pressure anisotropies are found to lead to the same asymptotic late time evolution. In other words, the difference between evolutions goes to zero at late times. There is an observed change in the time dependence. Moreover, the transition time is robust against the change in initial energy density or the interactions of the Quark-Gluon Plasma.

17.  Error Analysis of Model Atmosphere Variances in n-Capture Abundance Determinations

Lusk, Jeremy; Burris, Debra L.

University of Central Arkansas

The origin of light neutron capture elements is an unsolved problem of nuclear astrophysics. Previous studies have not been able to provide a satisfactory mechanism for the production of elements such as zirconium (Zr) yttrium (Y) and strontium (Sr) in the early galaxy. In a previous paper, we studied these elements using high-resolution spectra to reduce uncertainty. We now analyze possible sources of error in the computational models used to simulate the stellar atmospheres under observation - models that are used in the calculation of elemental abundances. By adjusting the model parameters such as effective temperature, microturbulent velocity, surface gravity, and metallicity we can judge the relative sensitivity of our calculations to errors in these values.

18.  Using Vernier Charge Sensors in an Attempt to Detect the Solar Wind

Odekirk, Tristan; Burris Debra

University of Central Arkansas

The project involves sending a charge probe into the upper atmosphere to measure charge. The research is based in the study of cosmic rays or highly charged particles emitted from various stellar sources. The charge probe has been used to detect beta particles from a source, and a correlation between charge detection and radiation reading are tests to be made. This shows a heightened likelihood of finding particles in the atmosphere. Supposing these charged particles are found further tests can be done for various fields including climate change and plasma physics. It has been shown that there is a correlation between heightened solar activity and global temperature, this project could branch to more significant measurements on climate-solar-activity-activity correlations. Pressure and density sensors could allow for research in plasma physics in the upper atmosphere. Essentially the project is a prod at potential. There is uncertainty in what will be found, the experiment is an attempt to view what potential there is in exploring the Arkansas atmosphere.

 

 

 

 

Poster Presentation Abstracts

 

 

Biology Posters

 

1.     Extending the Vase Life of Cut Roses (Rosa hybrida) by treatment with Different Preservatives

 

Anderson, L. Jr; Islam, Shahidul

University of Arkansas at Pine Bluff

 

Roses are favorite plants in home landscapes throughout Arkansas as well as other parts of the United States. This experiment revealed significant influence of different preservatives such as sucrose (C₁₂H₂₂O₁₁)and silver nitrate (AgNO₃) at different concentrations on the vase life of six (Tropicana, Peace, Iceberg, Eurpeana, Strike it rich and Double delight) roses (Rosa hybrida). It was found that different treatments had significant effect on each cultivar. The cultivars, tropicana, double delight and iceberg, excelled over others in all the treatments studied. Furthermore silver nitrate, in most of the cases, gave better performance than the sucrose in enhancing the shelf life of cut flowers of most of the cultivars. The concentration of sucrose @25 g L-1 superseded over the other sucrose concentrations with the value of 7.1 days in ‘tropicana’ and 6.4 days in ‘iceberg’ comparing the control (distilled water) with the average value of 4.2 days. In all the treatments containing sucrose and silver nitrate, the concentration of 150 ppm of AgNO3 prolonged the maximum number of days as compared to control. There is need for more trials to validate the results.

 

 

2.     Ecological dynamics of two communities of lignicolous myxomycetes in Costa

 

Rojas, Carlos; Stephenson, Steven L.

University of Arkansas

 

During the last decade, ecological studies of myxomycetes have provided mycologists around the world with a more complete understanding of the biology of the group. For this reason, the present study was designed to increase our understanding of the ecology of tropical lignicolous myxomycetes. An exhaustive survey for myxomycetes was carried out on two series of logs, one in a tropical rain forest and the other in a seasonal dry forest, in Costa Rica during 2007. Microenvironmental factors that could be measured were used to calculate niche breadth and resource competition by means of niche overlap in all species for both types of forest. Similarly, a series of parameters that are presumed to be associated with potential biotic advantages was used to recalculate the same estimators for the same groups under study. Likewise, both the geometric series and the broken stick model of community structure were compared with the empirical data in order to evaluate what theoretical model better explained the observed distribution of species. Overall, logs in the seasonal dry forest displayed both higher richness and diversity of myxomycetes than logs in the rain forest. Furthermore, mathematical estimations based on the observed data suggested that the seasonal dry forest could be more diverse than the rain forest. In most cases, niche breadth and overlap decreased when biotic parameters were analyzed. This suggests that such parameters might be important for obtaining a better estimate of the realized niche as supposed to the use of only macroenvironmental factors which could be related more to the estimation of the fundamental niche instead. For both types of forests, the geometric series model explained better the structure of the observed data. This suggests that niche preemption could be playing a more prominent role in the “shaping” of these tropical myxomycete communities than previously thought.

 

 

3.     Leaf Decomposition of a Non-Native-Species in an Urban Stream

 

Lewis, Sarah E.; Brown, Art V.

University of Arkansas

 

Leaf decomposition of three species of native Ozark vegetation was compared to that of one non-native species. Leaves were placed in a gravel-bed stream for 23 days. Temperature, flow, width, depth and discharge were monitored. Changes in mass and physical condition of the leaves were determined. The native species were Platanus occidentalis, Cornus florida, and Cercis canadensis. Lonicera maackii, the non-native species, was present throughout most of the understory within the riparian zone of the selected reach. Platanus occidentalis lost 24.6% mass, Cornus florida 30%, Cercis canadensis 37.5%, and Lonicera maackii 38.3%. Lonicera maackii did not maintain its overall leaf tissue structure as well as the native species. Platanus occidentalis maintained its structure most, followed by Cornus florida and Cercis canadensis. According to an ANOVA, significant differences existed between species with L. maackii correlating more closely with C. canadensis. Non-native species invasion within riparia can result in decreased species diversity within the stream community. Diverse leaf packs provide nutrients over a longer time because leaves become palatable at different times based on species chemistry and tissue structure. This affects the amount of time detritivores and decomposers have to take advantage of the allochthonous detritus. Non-native species have evolved different defenses against herbivores and pathogens. This can affect their rate of decomposition and transformation to fine particulate organic matter (FPOM) in streams. This rate of transformation can impact nutrient availability and thus energy flow at different trophic levels. This study shows that the presence of L. maackii in riparian corridors has the potential to impact the watershed ecosystem function of an Ozark stream.

 

 

4.     Mate Choice in Mantids: Does Sexual Cannibalism Allow Females to Avoid Inbreeding

 

Hurley, Kyle; Davis, Nicholas

University of Central Arkansas

 

In the local mantid Stagmomantis carolina, females often consume males before, during or after mating. The purpose of this behavior is unclear and observations of avoidance behavior by males suggest that a sexual conflict occurs. Males normally approach females from behind and freeze whenever the female turns in their direction. At approximately one body length from the female, the male jumps on top of the female and attempts to mate. Remarkably, the male abdomen can still attach to the female and apparently mate as the female consumes the male’s head. Females of S. carolina receive nutritional benefits by consuming males, but little is known about how females decide which sperm to use. Our goal is to test if female mantids determine kinship through consumption of the male and if they discriminate against kin. We also plan to test if males cannibalized during mating are able to fertilize eggs as effectively as non-cannibalized males. We have collected egg masses from the Jewel Moore Nature Reserve at the University of Central Arkansas in Conway and the Railroad Prairie Natural Area near Hazen to ensure non-related groups. Virgin females from each location will be paired with either sibling males from the same egg mass or non-sibling males from the other location. Ootheca produced by each mating will be hatched and the number of nymphs and infertile eggs will be counted to give a fertilization ratio. Our goal is to compare the reproductive success of intact and cannibalized males and to determine if females detect kinship during cannibalism.

 

 

5.     Genetic Diversity of Bumble Bees in Arkansas

Magnus, Roxane; Szalanski, Allen

University of Arkansas

A preliminary study on the genetic diversity of four species of bumble bees in Arkansas, was conducted using DNA sequences of a portion of the mtDNA 16S rRNA gene. Highest levels of genetic diversity was observed in Bombus bimaculatus (4 haplotypes), followed by B. griseocollis (2 haplotypes), and B. impatiens and B. pensylvanicus (1 haplotype each). Analysis of the DNA sequences will provide information on the amount of genetic diversity within each species and if any species have low levels of genetic diversity. Low levels of genetic diversity may indicate that the species has undergone a genetic bottleneck and may be at risk. Population genetic analysis will be conducted on the DNA sequences to determine if there are any populations of bumble bees that are genetically distinct. These populations may be locally adapted and movement of bumble bees into this area may displace these locally adapted populations.

6.     A Survey of Ants in Selected Prairies in Arkansas

Thompson, Lynne C.; General, David M.

University of Arkansas at Monticello

Prairies are one of Arkansas’ most endangered habitats. To assess the ant communities of selected prairie remnants in southern and eastern Arkansas, ants were sampled with pitfall traps. Prairies sampled in 2008 included Grandview Prairie WMA and Warren Prairie NA. Those sampled in 2009 included Locust Ridge Prairie (on Felsenthal NWR), and the following Arkansas Natural Heritage Commission NAs, Baker Prairie, Railroad Prairie, Downs Prairie, Konecny Prairie, and Roth Prairie. A total of 56,407 individuals in 40 species, 19 genera, and 4 subfamilies were collected. Sixteen of the 40 species were collected from single prairies. None of the species are unique to the prairies. Hierarchical cluster analysis showed that the southern prairies heavily infested with the exotic invasive Solenopsis invicta (red imported fire ant, RIFA) had different ant communities from the uninfested ones to the east. One interesting finding is that these RIFA infested southern prairies were missing 2 important species, Pheidole dentata and Temnothorax pergandei. Pheidole dentata was the dominant species in the uninfested prairies, with S. invicta dominant in the infested prairies. Two prairies that had more varied physiography (Locust Ridge and Railroad) also had much more species-rich communities.

7.     Detection of Inositol Polyphosphates by Polyacrylamide Gel Electrophoresis (PAGE)

Zafar, Maroof¹; Rizan, Mohsin¹; Hassen, Samar¹; Agarwal, Rakhee²; Ali, Nawab¹

¹University of Arkansas at Little Rock

²University of Arkansas for Medical Sciences

Inositol phosphates are naturally occurring compounds that regulate a number of cellular processes including apoptosis. Apoptosis is a mechanism by which cells undergo natural death in areas during a state that is harmful to the body. Previous works have shown that exogenously administered as well as endogenously manipulated inositol phosphates bring about apoptotic changes. It has been demonstrated that cellular levels of inositol phosphates, particularly higher inositol phosphates such as inositol hexophosphate (IP6) and dipho-inositol pentakis-phsophate (IP7), increase during apoptotic conditions. In this study, we have attempted to separate and identify these higher inositol phosphates by polyacrylamide gel electrophoresis (PAGE) and shown that cellular changes in inositol phosphate levels can be detected by this method. Cells were treated with etoposide to induce apoptosis, and apoptotic cells were observed under UV light following ethidium bromide/acridine orange staini ng. This staining showed that IP3 - IP6 induced apoptosis in SW480 cells with IP6 being the most effective inducing agent. The extracts from apoptotic and control cells were then loaded onto the polyacrylamide gel and run along standard IP6. Results showed that IP6 could be detected using the PAGE method. Using this technique, we have shown that cellular levels of IP6 were increased in SW480 cells, which were induced by etoposide. Our results demonstrated that this technique could be utilized instead of laborious radioactive labeling and HPLC separation method to study the changes in cellular levels of inositol phosphates. This method could also be used to detect IP7 levels following a modified gel staining procedure (DAPI).

8.     Myxomycetes Associated with Bryophytes

Bates, Amanda; Doss, Robin; Rojas, Carlos; Stephenson, Steven

University of Arkansas

Myxomycetes (plasmodial slime molds) often occur on substrates with bryophytes present, but few studies have considered the bryophytes themselves as substrates. In the present study, samples of bryophytes (but mostly mosses) were collected from three study sites in the United States (West Virginia, Montana and the Great Smoky Mountains National Park) along with study sites in Costa Rica and Canada. These samples were used to prepare series of moist chamber cultures. Based on results obtained thus far, bryophytes appear to be relatively productive as a substrate for myxomycetes. More than 50% of moist chamber cultures prepared with samples from Canada and the three study sites in the United States have yielded some evidence (either plasmodia or fruiting bodies) of these organisms, with the West Virginia study site the most productive (75%). Species of myxomycetes commonly associated with bryophytes are Arcyria cinerea, Cribraria microcarpa, Licea biforis and (especially) Trichia subfusca.

9.     Changes in invertebrate community structure along a longitudinal gradient in Big Piney Creek, Arkansas

Fuller, Chris; Entrekin, Sally; Johnson, Clint; Adams, Ginny; Adams, Reid

University of Central Arkansas

We measured changes in invertebrate community structure along a longitudinal gradient of ditches, streams, and wetlands in the Lower Mississippi River Delta Valley in Big Piney Creek watershed, Arkansas. The watershed is significantly altered from agriculture and associated hydrologic management. We hypothesized structural changes in the invertebrate community, along a longitudinal gradient from increased riparian inputs and shading, cooler water temperatures, and more complex habitat. Thus, we hypothesized that taxa richness and diversity of species would be highest in the wetlands, then streams, and lowest in ditches. Conversely, we hypothesized that invertebrate abundances would be highest in ditches, from greater primary production, and lowest in the wetlands. Preliminary data shows that abundance was higher at the ditch site (n=6) (mean±1SE, 1098±263), followed by the stream site (n=4) (567±271), and wetland site (n=4) (145±32) (p=0.0 46). Taxa richness was highest at the wetland site (18±1), followed by the ditch site (18±0.80), and stream site (11±1) (p=0.002). Simpson’s Diversity was highest at the wetland site (4.36±1.27), followed by the ditch site (1.88±0.22), and the stream site (1.62±0.17) (p=0.028). The effects of agriculture on the physical environment, and consequently the invertebrate community, could have negative effects on higher trophic levels, like fish, due to changes in resource allocation and availability.

10.  The Effects of Natural Gas Drilling on Decomposition Rates in the Fayetteville Shale Gas Play

Troutman, Tyler; Lowry, Michael S.; Entrekin, Sally A.

University of Central Arkansas

The natural gas industry is flourishing in the Fayetteville Shale gas play of north central Arkansas where over 1500 wells have been drilled in the last 5 years. The drilling processes have the potential to alter stream catchments by increasing road density, land clearing, reservoir creation, pipeline construction, and the use of biocides and other components of fracturing fluids. Natural gas wells are in close proximity to small streams, but few studies have examined whether installation of gas wells affects stream biota and associated functions, such as decomposition. Our study quantified the relationship between well density and decomposition rates in six small stream catchments in the Fayetteville Shale region. Our hypothesis is streams with higher well density will have greater rates of decomposition due to the potential for increased sedimentation and possible contaminants associated with well drilling. However, other land cover types m ay also affect rates. Decomposition rates varied among sites, ranging from 0.0072 to 0.0193 k•d-1, but there was no relationship with well density (r2= 0.03). Wood/herbaceous (r2= 0.69) land cover explained the most variation in decomposition rates among streams.

11.  An Ecological Study of Wood-Decomposing Fungi in Northwest Arkansas

Doss, Robin; Rojas, Carlos; Stephenson, Steven L.

University of Arkansas

Fungi play an important role in the decomposition of the coarse woody debris that accumulates in forest ecosystems. In the present study, surveys of wood-decomposing fungi are being carried out in forests throughout northwest Arkansas. Specimens of fungal fruiting bodies are collected in the field for identification, the forest type within which they are found is recorded, and a number of microenvironmental factors are measured or determined for the woody substrate upon which each fruiting body occurs. The latter include the level of wood moisture, the amount of light reaching the substrate, the size of the substrate, and the stage of wood decomposition. From the observations made thus far, it is apparent that there are many different species of fungi involved in the decomposition of coarse woody debris in the forests of northwest Arkansas. Analysis of initial data shows trends of certain species to occur more commonly within specific microenvir onmental parameters, but a larger data set is needed in order to strengthen the significance of these apparent trends. The overall objective of the study is to collect enough data to develop a better understanding of the species of fungi present and their distribution and overall ecology.

 

 

12.  An Ecological Survey of Arundinaria gigantea in Columbia County, Arkansas

Dockter, Katherine S.; Krosnick. Shawn E.

Southern Arkansas University

Arundinaria is a historically under researched lineage in the monocot family Poaceae. The genus is best known for its production of canebreaks, vast monotypic stands of native bamboo. Canebreaks are an important habitat for endangered species such as Swainson’s Warbler (Limnothlypis swainsonii) and Hooded Warblers (Wilsonia citrina) that are restricted to these areas. Canebrakes are a vital yet vulnerable part of wetland ecosystems. This study represents the first of a two-part research project intended to provide insight into the population density and distribution of the native cane species in southwest Arkansas, specifically focussing on Columbia County, Arkansas. The first part of the study seeks to document the habitat and population density of Arundinaria gigantea. To survey stand abundance, all primary paved roads in Columbia County were travelled during February-April, when broadleaf tree cover was least dense. Each unique stand was assigned a GPS waypoint centered at the middle of the observed stand. Stands were designated as unique if the distance between two stands was greater than 50 meters. For individual stands longer than one mile, a new marker was taken every mile and noted as being part of the same stand. Stands that crossed paved roads were considered to represent two stands. In this manner we were able to determine the areas of highest population density and the preferred environment in which these stands exist. Stands were divided into different classes based on ecosystem type. In general, extant stands tended to thrive in specific environments such as wetlands and bayous. In addition, observed stands are much smaller in size than those noted historically. It is clear that changing agricultural practices, development, and environmental factors such as pollution have greatly diminished the population density of A. gigantea in southwest Arkansas compared to pre-Colonial times. This study will be followed by an investigation into the genetic diversity of A. gigantea both within individual stands and across Columbia County.

13.  The effect of hydroperiod and invertebrate feeding on leaf decomposition rates in intermittent Ozark streams

Nix, Kasey J.; Entrekin, Sally A.

University of Central Arkansas

Intermittent streams have a hydroperiod that is regulated by the relatively predictable climate of a region. However, predictions based on global climate change indicate less frequent precipitation and greater severity, resulting in an overall increase in variability and unpredictability of intermittent stream flow. These changes in the regularity of the hydroperiod may directly affect the organisms living in the stream and cause significant changes in stream processes, such as leaf decomposition. We hypothesized that the rate of leaf decomposition would be greater in areas with longer periods of inundation and crayfish feeding would increase the rate of leaf decomposition compared to feeding by other invertebrates. Leaf bags were placed in different habitats within the same stream with different hydroperiods (pools and riffles) and leaf bags were prepared to include and exclude crayfish. We found that the rate of leaf decomposition was faster in areas with longer periods of inundation (pools: k=0.0051 d-1 vs. riffles: k=0.0028 d-1). Also, the rate of leaf decomposition was faster in riffles when crayfish were excluded (k=0.0037 d-1) versus crayfish included (k= 0.0028 d-1). Changes in hydroperiod length and invertebrate community composition may interact to cause significant changes to nutrient and energy flow through intermittent streams.

14.  A Review of Conservation Research Practices in Marine Aquaria

Canady, Candice S.

Southern Arkansas University

Originally marine aquaria existed primarily as a collection of rare and exotic species of aquatic life for the viewing pleasure of the public. However, within the past century the role of these institutions has changed dramatically and it is now apparent that these aquaria are becoming heavily involved in research and conservation, both within their facilities and in the wild. These institutions now contribute to conservation efforts in many ways. The goal of this research is to examine the apparent shift in priorities and the reasons behind this change. In addition, a comprehensive review of the methods by which marine aquaria are contributing to research and conservation will be provided. Preliminary information suggests that aquaria now go far beyond the expected method of simply educating the public on conservation of endangered species. They use a variety of methods to improve the chances of species survival, such as preserving genetic diversity of endangered species through in vitro fertilization. They also contribute to primary research about the maintenance of captive species in controlled environments (issues such as disease, diet, animal behavior, and interaction with environment). Aquaria now serve as examples for proper care and treatment of animals, both domestic and wild. These institutions act as both the voice of the public and of the scientific field of marine biology. By sharing the thoughts and opinions between the two communities, marine aquaria are a critical meeting point between these two disciplines. This, in turn, contributes to conservation on a global scale.

15.  The Plant Density of Justicia americana in Lake Maumelle, an Impoundment of the Big Maumelle River, Pulaski County, Arkansas

Sweeney, Sharon M.; Meredith, Bradley G.; Peck, James H.

University of Arkansas at Little Rock

Lake Maumelle, an impoundment of the Big Maumelle River in Pulaski County, Arkansas, is the primary source of drinking water for over 400,000 people in the greater Little Rock area. As the 50 year old reservoir ages, water quality enrichment and subsequent increased autochthonous organic carbon inputs to raw water quality are now evident. A detailed survey of the shore and aquatic vascular flora of the lake in the summer months of 2007 was presented previously. The data from that survey identified the presence of Justicia americana (water willow) in all of the investigated bays and promontories. This study quantifies the Justicia americana density per square meter in the lake and along the surrounding shoreline at waters edge. A total of 820 field observations provided students with plant density data and updated insight into the overall abundance of Justicia americana found growing at various depths in the lake body and along the shoreline. The overall average plant density was 25 plants per m² along the shoreline, 89 plants per m² at a water depth of 0.5 m and 59 plants per m² at a water depth of 1.0 m.

16.  Preliminary Data from Invertebrate and Fish Surveys of Big Maumelle River, Arkansas

Meredith, Bradley J.; Reese, Jeremy P.; Stehle, Jeremy P.; Mikel, Garrett A; Stroman, Justin A.; Payne, Forrest E.

University of Arkansas at Little Rock

The Big Maumelle River is located in the Fourche Mountain subdivision of the Level III Ouachita Mountains Ecoregion in Pulaski and Perry Counties. Approximately 98% of the Big Maumelle watershed is forested above the lake Maumelle impoundment. During the summer of 2007, macroinvertebrate samples were collected at three sampling locations using Hester-Dendy artificial substrates, along with basic water quality and physical habitat data. In June 2008, with the assistance of the Arkansas Department of Environmental Quality (ADEQ), two of the stations were sampled for fish with electrofisher equipment. Substrates throughout the Big Maumelle River were variable, ranging from cobble and gravel with occasional boulders to silt. Several simple metrics were used to assess the community structure. The abundance of ephemeropterans, plecopterans and tricopterans indicated low levels of degraded water. The fish community at the two sites sampled was dominated by darters, sunfish and minnows, which is typical for a relatively undisturbed Ouachita Mountain Ecoregion stream.

17.  Identification of Polyphenols in Tomato Leaves by HPLC with Photodiode Array Detection and Electrospray Ionization Mass Spectrometry

Grace, Stephen C.

University of Arkansas at Little Rock

Polyphenols are natural plant phytochemicals that have attracted interest for their antioxidant and health promoting properties. In addition, certain environmental stresses such as high light, low temperatures, ozone, and pathogens often induce the biosynthesis of polyphenols in plants. To better understand the biological function of these secondary metabolites, it is important to be able to characterize diverse chemical structures simultaneously in complex mixtures and extracts. With this in mind, we developed a method to identify and quantify soluble polyphenols in tomato leaves (Solanum lycopersicon) using high-performance liquid chromatography combined with photodiode array detection and electrospray ionization mass spectrometry. A total of 22 compounds were identified based on their UV-absorption properties, mass spectra, and retention times relative to known standards. In addition to the well known metabolites chlorogenic acid and rut in, we identified several other caffeoyl esters and flavonol glycosides of quercetin and kaempferol, including the previously undescribed compounds caffeoylglucaric acid and feruloylglucaric acid. Three anthocyanins were resolved by HPLC and identified as petunidin glycosides by mass spectrometry. We also identified the polyamine tris-(dihydrocaffeoyl) spermine using positive and negative mode ESI-LCMS. Several polyphenols produced in tomato leaves were either not detected or were present in trace amounts in ripe tomato fruits. This suggests that the polyphenol composition of fruits can be improved by traditional breeding and/or metabolic engineering techniques.

18.  Photoregulation of polyphenol biosynthesis in the hp-2dg mutant of tomato

Chen, Chen; Grace Stephen C.

University of Arkansas at Little Rock

Polyphenols are plant secondary metabolites that include flavonoids, hydroxycinnamic acids, and other bioactive phenolic compounds. They have attracted interest as dietary antioxidants and as chemoprotective agents against coronary heart disease, neurooxidative stress, certain cancers, and other age-related diseases. They also serve a multifaceted role in plant resistance to various biotic and abiotic stresses. Despite their importance in both plant metabolism and human nutrition, many aspects of the regulation of polyphenol biosynthesis in plants remain unclear. In this study, we examined the effects of light intensity on the expression of 8 genes involved in phenylpropanoid and flavonoid metabolism in the hp-2dg (high pigment) mutant of tomato (Solanum lycopersicon) using quantitative real-time RT-PCR. The hp-2dg mutant produces high levels of anthocyanins in leaves and fruits; however, this effect is only observed under high light condit ions. We also measured expression of the Anthocyanin1 (Ant1) gene which encodes a Myb transcription factor known to be involved in anthocyanin synthesis. Finally, we measured polyphenol concentrations in leaves by high performance liquid chromatography in an effort to correlate gene expression with the accumulation of specific phenolic metabolites. The aim of these studies is to elucidate the physiological and biochemical factors that regulate phenylpropanoid biosynthesis in plants, knowledge that has practical importance in the development of crops with enhanced nutritional quality and stress tolerance.

 

 

19.  Calling Phenology of Anuran Populations Surveyed in Southwest Arkansas Using Acoustic Surveys

Risher, Sarah R.; Baker, Claude D.

Southern Arkansas University

Over the last hundred and fifty years, dramatic changes have occurred in our Arkansas environments, posing significant challenges for animals and plants. Frogs and toads have been influenced by human activities resulting in the decline of certain amphibian populations in the Southwest and other states. Habitat loss and exposure to various contaminants have been found to influence amphibian decline. The purpose of this study is to rapidly assess the frog populations of SW Arkansas by monitoring local frog calls in a number of breeding habitats. Our frog call surveys utilize a protocol coordinated by the US Geological Survey`s Patuxent Wildlife Research Center. For this study, students at Southern Arkansas University periodically monitor sites by listening — “frog-watching” — three minutes for frogs and toads after dusk. Modern networking, texting and use of cell phones as recording devices have assisted in this effort. Preliminary results indicate that significant numbers of frogs and toads are present in our area. The conversion of agricultural areas into pine and hardwood forests may be a factor contributing to high numbers of frogs and toads.

20.  A Kinematic Analysis of Drop Landing in Military Boots

Booker, Jacquelynn M.; Oliver, Gretchen D.; Stone, Audrey J.; Plummer, Hillary

University of Arkansas

A Kinematic Analysis of Drop Landing in Military Boots Booker, J.M., Oliver, G.D., Stone, A.J, Plummer, H: University of Arkansas, Fayetteville, AR Context: Previous studies have shown that proper landing mechanics have a significant role in preventing knee injuries from drop landings during athletic events [1,2]. Although the unique footwear and training used in the military setting may have an impact on landing mechanics and lower extremity injuries, drop landings in this setting have not been studied as thoroughly. Objective: The purpose of this study was to investigate the effect that military boots have on the knee-valgus landing position compared to standard running shoes and bare feet during a drop landing. Design: A completely randomized design with each participant acting as their own control was used in the study. Setting: The study was conducted in a controlled laboratory setting. Participants: Sixteen college aged military personnel (Age: 21±3 yrs; Weight: 79± 12kg; Height: 172± 10cm) that have had training and familiarity in military boots, participated in the study. Interventions: Drop landings were conducted under three conditions: bare feet, running shoes, and military boots. Knee kinematics were determined using the Motion Monitor electromagnetic tracking device. Following set-up and pre-testing protocols, the participants were familiarized with the procedure for landing from a height of 60 cm. Once the participants were familiar with the landing height, they were given a random order of footwear condition in which to perform the drop landing. Data describing knee kinematics were collected for each trial. Data were analyzed using a repeated measures multivariate analysis of variance. Main Outcome Measures: Knee abduction angle and ground reaction forces were analyzed. Results: A repeated measures multivariate analysis of variance (MANOVA) followed by post hoc ANOVAs for each measure were used to determine specific group differences within each measure. The results found significant differences among footwear for ground reaction (feet: 211.5%±46.1%, shoe: 241.53%±48.78% , boot: 235.54%±56.29%; p < .05). However there were no significant differences between knee valgus and foot conditions among different footwear. Findings: Although there was no effect for foot conditioning on knee angle, the effect on ground reaction forces has implications for injury risk for military personnel. Further analysis of the role of knee flexion when combined with increased ground reaction forces could lead to more detailed results.

21.  Student perceptions of the BMI as an overall indicator of health

Davis, Cory; Krosnick, Shawn E.

Southern Arkansas University

In today’s society it is easy to become overloaded with advertisements showcasing the perfect actor or actress and their perfect bodies. From the beginning of time weight gain and physical fitness has been the number one epidemic to threaten society. Being “perfect” is all we see. In 2003, the Arkansas legislature signed into law Act 1220 that mandated each high school student’s body mass index be measured and reported to their parents. The legislature, along with Governor Huckabee, believed this was a guarantee that Arkansans would be educated about this epidemic. Many schools completed the measurements without any specific follow up provided for the students. Since the passing of this bill, the state has worked to revamp these requirements and give the results a more practical use. Although the state educational system has attempted to provide the students with proper habits and a firm foundation for a healthy lifestyle, it is clear that lit tle was done with the student’s measurements. The student body at Southern Arkansas University, Magnolia, was surveyed in order to quantify the effect that knowing one’s body mass index has on their outlook on life. Twenty questions spanning topics relating to caloric intake, physical fitness/activity, body image, and overall health were posed to the students. Results were analyzed using the chi-squared statistic. Preliminary results indicate that SAU students are unaware of how their lifestyles affect their body mass index, and vice versa. The results demonstrate a need for greater prioritization of public education efforts regarding this measurement of health. Suggestions for alternative health assessments were also sought from the student body. On the basis of these data several recommendations are made regarding the use of BMI in elementary schools. Greater emphasis should be put on muscle mass, bone density, and body fat percentage as opposed to the BMI. It is clear that more is involved in determining obesity than just a student’s height compared to their weight.

22.  A Biological Inventory of Meacham Cave (Independence County, AR)

Thomas, David J.; Ong, Han C.; Foll, Megan N.; Robinson, Greg; Middaugh, Chris R.; Morgan, Charles

Lyon College

At Lyon College, BIO349 Earth Systems is a multidisciplinary Earth science course for biology majors. As an experiment in pedagogy, students participated in a field study of nearby Meacham Cave in place of the traditional “cookbook” laboratory sessions. During the spring 2009 semester, students alternated between field sessions in and around the cave, and lab sessions during which they analyzed samples and data from the field. Although the study of Meacham Cave is part of an ongoing research project, we report on findings from 29 January 2009 through 26 February 2010. Students analyzed soil texture and pH, sampled cave water and tested for coliform bacteria, measured total microbial biomass in soil and water, and inventoried macroscopic animals and plants in and around the cave. We found that the cave soils consist almost entirely of clay, and that they have a relatively active microbial biomass (measured as total esterase activity). P resumptive fecal coliforms were found in water samples throughout the cave. Notable vertebrate animal species within the cave included cave salamanders (Eurycea lucifuga), pickerel frogs (Rana palustris), big brown bats (Eptesicus fuscus) and Eastern pipstrelle bats (Pipistrellus subflavus). While the cave contains a transitory pool of water at its lowest point, no aquatic invertebrates were found. This biological inventory provides a baseline for longer-term biological monitoring of Meacham Cave. This research is funded by the Arkansas Space Grant Consortium.

23.  Photosynthetic Microorganisms from Ozark Region Caves

Kuehl, Melissa; McQueen, V. Michael; Moreno Martha; Ong, Han Chuan; Thomas, David J.

Lyon College

Mars and the Moon possess evidence of caves, and caves are expected on most rocky and icy bodies in the solar system. Particularly on Mars, caves represent possible currently-habitable environments – good targets for the search for life. Here, we report on part of a project to isolate and identify autotrophic microorganisms from cave environments. Microbes were isolated from water sources and surfaces in Ozark Region caves: Bat Cave (Walnut Grove, AR), Blanchard Spring Caverns (Fifty-six, AR), Blevins Cave (Batesville, AR), Blowing Cave (Cushman, AR), Cave Point Cave (Pleasant Grove, AR), Indian Rocks Caves (Fairfield Bay, AR), Meacham Cave (Batesville, AR) and Tumbling Creek Cave (Protem, MO). Water samples were plated onto BG-11 agar and incubated at 12°C with illumination by cool-white fluorescent tubes (10-50 mmol photons m-2s-1). We transferred visible colonies to fresh BG-11 plates for confirmation of photoautotrophic growth. Chromosomal DNA was isolated from subsamples of each culture; 16S rRNA gene sequences were amplified and cloned for sequencing and identification. Sequence results are being compared with microscopic observations to identify the microbes (work in progress). Additional metabolic tests were performed as well, and those results will be reported. Preliminary results indicate that photosynthetic microbes are more common in caves that have streams flowing through the sample sites. The NASA/Arkansas Space Grant Consortium funds this research.

24.  The Transformation of Rubus and its Application to the Study of Plant Secondary

Gates, Nadine; Parker, Kayla; Walker, Courtney; Skiver, Natasha

University of Central Arkansas

Transformation is the genetic alteration of a cell resulting from the uptake and expression of foreign genetic material (DNA). The ability to perform transformation is a technique that has yet to be accomplished in blackberry. To this end, we used Agrobacterium-mediated transformation techniques to transform the blackberry (Rubus spp) in tissue culture. A vector containing a GFP reporter gene was used to produce transgenic tissue. Results thus far have revealed the successful transformation of blackberry callus and studies are ongoing. We intend to use this system to aid in the study of secondary metabolites in Rubus. Plant secondary metabolites provide many leads for new therapeutics that are currently on the market, however, their mechanism of action is often not understood in either plants or animals. We hypothesize that phenolics (a class of secondary metabolites) represent a class of plant hormones that activate developmentally-regulated signal transduction pathways and are also able to activate mammalian signaling pathways by mimicking small ligands.

25.  Stimulatory and protective role of glycoconjugates on rice seeds from Bacillus spores infection during germination and growth

Hassen, Lahiani Mohamed; Tarasenko, Olga

University of Arkansas at Little Rock

Agroterrorism is the potential risk or consequences of the release of a virulent pathogen that kills crops, which could cause overwhelming problems, related to health and stability of nations. Novel naturally occuring infectious diseases made it clear about the devastating threat of agroterrorism. Glycoconjugates (GCs or sugars-bearing polymers) have a potential for recognition and inhibition infections caused by Bacillus and other pathogens. The objective of the present study focused on A) the rice seed response to GCs treatment and B) the degree of efficacy of each GC used. Each GCs were independently employed to treat rice seed prior to, during and following exposure conditions to B. cereus spores. Data was collected based on seed germination and plant growth. Results showed that in the presence of GCs, seeds were able to germinate faster and overcome B. cereus spore infection. Results demonstrate that GCs protected seeds and helped the growth of a vigorous plant. The findings of this research provide new insides on the development of new treatments against bacterial infections in order to protect crops from bacterial infection and/or agroterrorism.

 

 

26.  AFLP markers for mapping genomes in plants

Martin Jr., Darrell; Wild, Michael; Noyes, Richard D.

University of Central Arkansas

Amplified fragment-length polymorphisms (AFLP) data were used to produce markers for genetic mapping in the flowering plants Erigeron annuus and Erigeron strigosus (Asteraceae). Crosses of triploid (3n=27) apomictic and diploid (2n=18) sexual parents gave rise to an F1 population ‘N1’ of 336 progeny. DNA was isolated from each individual and AFLP markers produced using 30 combinations of selective primers fluorescently labeled with NED or VIC. Capillary gel electrophoresis of ‘pool-plexed’ reactions were run on an ABI 3730. Electropherogram analysis found informative segregating markers and a binary matrix for markers either present (scored 1) or absent (scored 0) was produced for the progeny. A master matrix of all markers (~400) will be analyzed using the program MapMaker to generate linkage groups representing the genome of the triploid parent.

27.  Segregation for seed formation in complex apomict sexual crosses in plants

Burrow, Halee; Desrochers, Claire; Richardson, Harry; Brummett, Shawn; Noyes, Richard D.

University of Central Arkansas

Genetic analysis of traits relies on the variation in trait value. Apomixis, asexual seed production, is a naturally occurring phenomenon that is genetically controlled. The goal of the experiment is to study apomixis trait variation, measured by estimating seed production, in hybrid F1s between triploid (2n=27) apomictic pollen donors and sexual diploid (2n=18) seed parents. Results show considerable variation in the ability of F1s to make seed with a small number of individuals exhibiting transgressive segregation. Data will be used for mapping genes that control levels of apomictic seed production.

28.  AFLP markers for mapping genomes in plants

Roberds, Aaron; DiGiacomo, Rebecca; Noyes, Richard D.

University of Central Arkansas

Many different classes of genetic markers can be used for mapping genomes. The only requirement is that segregation must be present. In this experiment we evaluated length differences of intronic regions for potential use in genetic mapping in plants. PCR conditions were optimized for 24 primer pairs published for intronic regions of unigenes in the plant family Asteraceae. Products were visualized on an ABI 3730 capillary sequencer using fluorescently tagged universal primers. The preliminary results demonstrate differences in the length of intronic regions among individuals. Segration for this putative allelic variation will be evaluated among progeny in controlled crosses.

 

 

29.  Pollen size variation and reproductive success for triploid apomictic plants

Larson, Signe; Noyes, Ricard D.

University of Central Arkansas

Apomictic plants achieve reproductive success through their seed (produced asexually) as well as through pollen. Crosses between triploid apomicts and sexual diploids in Erigeron (Asteraceae) yield a bimodal distribution consisting mostly of diploid and triploid hybrids indicating reduction during pollen formation from 3n to n and 2n. The hypothesis of bimodal pollen was investigated by examining the size variation and quality of pollen produced by triploid apomicts by plotting pollen diameter against pollen size controls. In contrast to expectation, the pollen produced by triploids is unimodal and centers on 1.5n . This suggests that most pollen produced by triploids is wasted and that reproductive success comes from low amounts of pollen made at the tails of distribution.

30.  Effectiveness of a Gentle on Spore Contaminated Stainless Steel

Pavan, Casey; Tarasenko, Olga

University of Arkansas at Little Rock

Stainless steel materials are widely used in the field of biological and pharmaceutical research. Despite stainless steel being a resilient substance it is used around, or in the construction of sensitive equipment. This becomes problematic when we consider that the majority of compounds currently used as disinfectants can be disruptive to the operation of, or outright destructive to the operation of such delicate instruments. The objective of this research is to study if glycoconjugate solutions (GSs) can act as a “gentle” disinfectant that is suitable for decontamination use on stainless steel surfaces. In this study, ten GSs (1-10) were tested on stainless steel foil AISI-Series 200/300/400 (THERMA-FOIL Dayville, CT 0241). The efficiency of each GCs was assessed by exposing the steel surface to Bacillus cereus spores and GCs at the same time. The resulting solution is plated on TSA plates. The GCs with the fewest CFUs is determined to be the most efficient. Our results show that the GCs6 consistently achieves a 97% spore B. cereus disinfection rate on stainless steel. It should also be noted that GC solution has the property of being safe for use around humans. This opens up the possibility for other applications, such as decontamination of stainless steel kitchen surfaces and cookware.

31.  Genetic Analysis of Regions on Chromosome Z for Contribution to Pulmonary Hypertension and Ascites in the Chicken

Chinn, Allison M.; Anthony, Nicholas B.; Erf, Gisela F.; Wideman, Robert F.; Rhoads, Doug D.

University of Arkansas

Chronic Pulmonary Hypertension is a major disease affecting humans for which there is no generally accepted animal model. Our group has been validating the ascitic chicken for application as a medical model for human Idiopathic Pulmonary Arterial Hypertension (IPAH). Ascites is commonly observed in broiler chickens where increased pulmonary vascular pressure results in the accumulation of large amounts of fluid in the abdominal cavity of the birds. Ascites is a commercial concern for the poultry industry, but the underlying physiology and pathology approximate IPAH in humans. In a genome-wide SNP survey of ascites resistant and susceptible lines, we identified 9 chromosomal regions that showed Linkage Disequilibrium (LD) with respect to ascites susceptibility and ventricular hypertrophy. Previously, we used VNTR (Variable Number Tandem Repeat) genotyping to confirm segregation distortion for five of the regions in an analysis of susceptible and resistant birds from a line selected for enhanced susceptibility. Two regions on the sex chromosome Z have not been fully examined. We have completed analysis of one of these regions using VNTRs. For this region we detected 5 alleles with one showing significant linkage disequilibrium for ascites. The association was strongest in males. A second allele showed the opposite trend but not significant to the 0.05 level. Analysis of the second region using qPCR-HRM based SNP analysis is underway.

32.  Molecular characterization of a family of transcriptional regulators – CCAAT-binding factors – in the plant-pathogenic fungus Fusarium verticillioides through targeted gene disruption

Ridenour, John B.; Bluhm, Burt H.

University of Arkansas

The ascomycete fungus Fusarium verticillioides is a ubiquitous pathogen of maize, attacking seedlings, kernels, and stalks. Additionally, F. verticillioides produces fumonisin mycotoxins that cause cancer and other illnesses when ingested by humans or livestock. Currently, little is known at the molecular level regarding pathogenesis or mycotoxigenesis in this important fungus. The goal of this study was to identify genes and regulatory mechanisms underlying pathogenicity and fumonisin biosynthesis in F. verticillioides. Recent whole-genome analyses of F. verticillioides identified 653 genes predicted to encode transcription factors. In this study, an entire family of putative transcriptional regulators – CCAAT-binding factors – was functionally characterized through reverse genetics. To this end, a high-throughput methodology utilizing split-marker homologous recombination was optimized for targeted gene disruption in F. verticillioides. The genome of the fungus is predicted to contain six CCAAT-binding factors, all of which were targeted for disruption with the newly-developed technique. For five of the six putative CCAAT-binding factors, at least four independent mutants were created; disrupting the sixth sequence appeared to be lethal. Mutants were verified by Southern blot analyses and phenotypically characterized. For each mutant, morphology, pathogenesis, kernel colonization, and fumonisin biosynthesis were analyzed. At least one of the genes was required for wild-type levels of kernel colonization, and at least two of the genes were required for wild-type levels of fumonisin biosynthesis. This study is the first systematic analysis of fungal CCAAT-binding factors in the context of plant pathogenesis and the first successful attempt to characterize an entire family of transcriptional regulators in F. verticillioides. This study provides new insight into the molecular-level regulation of pathogenesis and fumonisin biosynthesis, and through the optimization of split-marker gene disruption, opens the door for subsequent high-throughput techniques in molecular genetics.

33.  The Distribution of erm A and erm C among Staphylococci

Fu, Xing; Gilmore, David

Arkansas State University

Staphylococcus is a genus of bacterium found as a commensal among a variety of mammals including dogs and humans. Antibiotic resistant strains of the most pathogenic of these (MRSA) are making treatment of infections more difficult. In a study of staphylococci isolated from pet industry employees, we have found a considerable amount of antibiotic resistance, even among species other than S. aureus. As determined by Kirby Bauer disk diffusion assays, erythromycin resistance is the second most common after resistance to penicillin. Erm A gene and erm C gene are the most prevalent erythromycin resistant genes in staphylococci. Plasmid DNA coding for both penicillin and erythromycin resistance generally contains the erm A gene. According to former research, erm C gene is more prevalent than erm A gene, however, the proportion of isolates possessing the erm C gene, as determined by PCR, was lower than anticipated. Data will be presented on the distribution of erm A and erm C among these staphylococcal isolates.

34. Benthic Macroinvertebrate Food Web Patterns in a Headwater Streams Prior to Riparian Zone Restoration

 

Jensen, Nicki¹; Evans-White, Michelle²; Haggard, Brian²

¹University of Central Arkansas

²University of Arkansas

Despite the popularity of stream restorations, few are monitored to assess the success of the restoration activity. Successful monitoring includes collection of data to assess the stream community and ecosystem prior to, during, and after the restoration. The Division of Agriculture at the University of Arkansas plans to restore 235 acres of the riparian buffer zone along a headwater stream that receives urban stormwater and agricultural runoff in 2009. We expect that this riparian buffer restoration will alter the relative importance of autochthonous and allochthonous food resources fueling the stream food web and allow a more diverse community structure of benthic macroinvertebrates to occur. We collected samples of food resources (periphyton, leaves, and grasses) and benthic macroinvertebrates from three sites upstream of and four sites within the restoration zone in summer 2008. We analyzed the stable carbon (C) and nitrogen (N) isotopi c composition (ratios of 13C/12C and 15N/14N) of all food web components to examine the relative importance of autochthonous (periphyton) and allochthonous (deciduous leaves and grasses) food resources to benthic macroinvertebrate species prior to the restoration. The dominant food resources were grasses and algae. The C signature of dominant food resources varied significantly (F=10.63, p=0.009; mean (+1SD) d13C for grasses = -28.0+3.2 and for periphyton = -23.2+1.2); however, the N signature did not (p=0.957; mean (+1SD) d15N for grasses = 13.0+2.1 and for periphyton = 12.8+2.6). Dominant macroinvertebrates included Corixidae, Physellidae, Chironomidae, Asellidae, and crayfish. Most species had d13C values that were more similar to periphyton than to grasses suggesting that the macroinvertebrate food web was fueled primarily by autochthonous resources in the summer. Future research will examine food web patterns seasonally before, during, and after the scheduled restoration.

35.  Silver Solution as an Alternative Surface Disinfectant

Fletcher, Diana; Black, Viktoriya

Southern Arkansas University

Recent evidence has been presented indicating chlorine bleach gives rise to a carcinogen and can contribute to childhood asthma when used extensively as a cleanser. No information is available to indicate silver is unsafe for environmental use. If silver can be shown to be effective as an antimicrobial, it can be an environmentally friendly and healthier alternative to chlorine bleach cleaner. In this study, we tested the effective of a silver cleaner to a bleach cleanser and publish the results.

36.  Statistical analysis of Ebola outbreaks

Fletcher, Diana¹; Black, Viktoriya¹; Bassett, Denene²

¹Southern Arkansas University

²University of Arizona

 

This is an overview of  the hemorrhagic virus Ebola. Following the first recorded outbreak in 1976, massive efforts have been employed to classify and eradicate this virus. We must use every method at our disposal to examine  this virus. The aim of this statistical analysis is to correlate information and search for any patterns of outbreak.

 

 

37.  Do girdles and saliva promote growth in notodontic caterpillars?

 

Moon, Deborah; Dussourd, David

University of Central Arkansas

 

Caterpillars in the family Notodontidae often chew furrows around leaf petioles or stems. This girdling behavior has been reported in seven notodontid species feeding on six families of economically important trees, including species of oak, birch, pecan, willow, cherry and elm. The function of girdling by notodontids is still unknown. Girdles may benefit caterpillars by disrupting the vascular tissues or by allowing caterpillars to introduce salivary components into the wound. Caterpillars have been observed rubbing the tip of the labium where the salivary glands empty onto the surface of the girdle. To test if girdles increase caterpillar growth rates, and specifically if saliva improves growth, we plan to compare larval growth over 3 days on control birch stems, birch stems with natural girdles (cut by another cohort of caterpillars), and birch stems with artificial girdles. If girdles and oral secretions enhance growth, we predict that larvae too small to cut their own girdles will grow faster on the girdle treatments and fastest on stems with natural girdles.

 

 

38.  AASM Abstract

 

Bewley, Autumn

University of Central Arkansas

 

The purpose of our study is to test immune responses to a Nickel-based compound in both mercury susceptible and mercury resistant mice. We want to determine if this compound might be safely used as an anti-tumor drug in humans. We would like to repeat out pilot study to confirm if this anti-tumor compound induces any autoimmune responses as a side effect in mice. We would like to build upon the results of the pilot study. We will be not only expanding the scope of the experiment, but also adding groups of a mouse strain that is genetically resistant to heavy metal induced autoimmunity. This will indicate if the induction of autoimmune response is specific to the genetically susceptible mouse strain. The mice will be injected with subtoxic doses of the nickel compound, and blood serum samples will be extracted for analysis. Pan-IG-immunofluorescence will be utilized to label the antibodies with fluorescent dyes so they may be visualized with a microscope. Sera ELISA’s will allow us to assess the total antibody levels in the serum samples. We will be looking at IgM, IgG1, and IgE. IgG1 and IgE levels tend to rise in response to heavy metals and IgM levels will provide additional information. We predict that autoimmunity will be induced in genetically susceptible mice, but not in genetically resistant mice. If autoimmunity is not induced in the resistant mouse strain this may mean that the compound could be used in humans if they do not have a heavy metal susceptibile genotype.

 

 

 

39.  Is Didymium pertusum a “good” species of myxomycete?

 

Parks, Shaina S; Stephenson, Steven

University of Arkansas

 

The plasmodial slime molds (or myxomycetes) are a little known but fascinating group of organisms found in habitats all over the world.  For one part of their life cycle, they exist as microscopic amoeboid cells.  In another part, they exist as a multinucleate structure called a plasmodium that ultimately gives rise to fruiting bodies containing spores.  As with many microscopic organisms, the small size of slime molds makes it difficult to use characters to define a species.  This causes problems when one tries to use morphological differences to separate closely related forms.  Frequently, molecular techniques are crucial in the study of these situations.  For the slime molds Didymium pertusum and Didymium squamulosum, morphological differences have not proven sufficient to determine if the former is a distinct species, and molecular techniques are needed.  In this project, specimens identified as D. pertusum are being cultured and DNA isolated from these cultures.  Polymerase chain reactions are being performed to obtain sequences of DNA from D. pertusum.  DNA sequences from the latter will be compared with those of D. squamulosum to determine if D. pertusum is indeed a separate species or simply a morphological variant of D. squamulosum.  The sequenced genes will also be used to develop a data set to determine the phylogenetic placement of D. pertusum within the genus Didymium.

 

 

40.  Phototropic and Gravitropic Responses of Arabidopsis thaliana

Hunter, Charles N.; Taylor, James G.

Ouachita Baptist University

 

This experiment shows the growth of Arabidopsis thaliana (wild type Columbia and the auxin mutant AX4) after clinorotation with light vectors placed vertical or horizontal.  The study was conducted to determine the gravitropic and phototropic response of plant growth in simulated low gravity conditions.  Data were collected during the first nine days of growth.  The plants were controlled in light boxes to maintain the same micromoles of light and temperature.  The experiments were designed to measure the morphological development of Arabidopsis plants in response to altered gravity perception using a clinostat.  The results were collected using photos of each experiment and measured by Image Tool software to examine the dimensions of each plant’s growth. The results indicate that when the perception of gravity is altered and the light vector is from the horizontal position, phototropism has a greater effect than gravitropism in the roots of Arabidopsis thaliana (Columbia).  This study is different than others previously recorded because the Arabidopsis (Columbia) plants overcame the gravitropic response turning directly to the light creating positive phototropism for the roots on a horizontal clinostat.  This shows the phototropic response appears to have “trumped” the gravitropic response of the wild type Arabidopsis (Columbia).  The non-response of AX4 by exhibiting growth away from the light vector on a horizontal clinostat implies that perhaps auxin has a role in the response of the wild type Arabidopsis in this situation.

 

 

41. Analysis of B-Cell Antibody Gene Segment Use in Response to Mercury Treatment

 

Clarke, Heather

University of Central Arkansas

 

A.SW congenic strain mice have been used for three decades as a model of chemically-induced autoimmunity. When introduced with mercuric chloride (HgCl₂), a defined autoimmune response results in these mice, characterized by antinucleolar antibodies (ANoA) of the IgG1 and IgE isotypes. Although many studies have been conducted utilizing this mouse model, none have examined specific antibody heavy-chain gene segments of mature, circulating B-cell receptors (BCRs) which are selected in response to mercury treatment. Using nested polymerase chain reaction (PCR), individually sorted B-cells from treated and sham-treated were examined for heavy-chain material which could be amplified. This method was then followed by sequence analyses of gel-purified products in order to identify individual V(D)J gene segments used by B lymphocytes from treated and non-treated mice.

 

 

41.  Hyaluronidase Gene (hysA1 and hysA2) Expression in Staphylococcus aureus

 

Ward, James¹; Wanrer, P.²; Hart, M. E.²

¹Ouchita Baptist University

²National Center for Toxicological Research

 

Staphyllococcus aureus is a pathogenic bacteria that produces several virulent proteins that denature animal cellular components. One of these proteins, hyaluronidase, catabolizes hyaluronic acid, a major structural component of the cell matrix. Hyaluronidase is coded for by two genes, hyaluronidase 1(hysA 1) and hyaluronidase 2 (hysA 2). Known regulators of S. aureus’s hyaluronidase gene expression are staphylococcal accessory regulator (sarA) and accessory gene regulator (agr). The goal of this study was to determine how sarA and agr regulates the hysA 1 and hysA 2 genes at the RNA level. A knockout sarA strain, a knockout agr strain, and a sarA/agr double knockout strain of S. aureus were grown and total mRNA was isolated at 0, 3, 6, and 12 hours after inoculation in nutrient media (37^o C). Expression levels for hysA 1 and hysA 2 were measured using Quantitative Polymerase Chain Reaction (Q-PCR). Results of the experiment showed a heightened expression of hysA 1 and hysA 2 in both the sarA and sarA/agr knockout strains, which supports the sarA regulator as being an inhibitor of the hysA 1 and hysA 2 genes. Results for agr were inconclusive for both hysA 1 and hysA 2 gene regulation, so further research will need to be done for conclusive results. Knowledge of specific sarA and agr regulation of hysA 1 and hysA 2 will allow mechanisms to be formulated to possibly prevent the expression of hysA 1 and hysA 2 and subsequently reduce the virulence of S. aureus.            

 

42.  Photosynthetic Effects of Light Intensity and Frequency on transgenic Arabidopsis Thaliana plants with increased levels of Chlorophyll b.

 

Reyna, Nathan S.

Ouachita Baptist University

 

Plants respond to changes in light intensity by increasing or decreasing the size of their light harvesting antenna complex.  In low light intensity, the antenna size increases and the chlorophyll a/b ratio decreases respectively.  The opposite is observed in high light intensity. Research has shown that high chlorophyll b (Chl b) levels in relation to chlorophyll a (Chl a) are responsible for the increased antenna size.  The alteration of antenna size in relation to light levels, leads one to suspect that an increased antenna complex would result in higher CO₂ assimilation (photosynthetic rate).   However, current research in our lab working with transgenic Arabidopsis thaliana, with elevated chlorophyll b levels, suggests other biochemical properties may be limiting factors of photosynthesis.  An accumulation of student research projects examining the effects of light intensity (high, medium, low) and frequency (blue 460nm) on global gene expression using microarray, ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) protein expression, Chl a/b ratios and photosynthetic rate will be presented.  Further we will present how similar projects are conducted for inquiry based learning outcomes in an upper division molecular cell biology class at Ouachita Baptist University.  

43.  Ultrasound Evaluation of Human Motion

Lieblong, Joshua

University of Central Arkansas

Doppler ultrasound is being evaluated as a tool for characterizing human motion.  A high frequency sound wave is transmitted toward a moving object, which then reflects frequencies shifted from the transmitted frequency due to the velocity of the object.  A physical pendulum has been used to model the behavior of a leg.  The prototype apparatus of the previous experiments is being examined to minimize the “overshoot” found.  After the interaction between the acoustic signal and a single physical pendulum is understood, double physical pendulums can be compared to a person’s gait.  The comparison can be used to model an individual’s walk to distinguish that person’s mood, mass, or even a type of identification system for oscillatory human motion.

 

 

Chemistry Posters

 

1.     Bis(m-naphthalene-2-thiolato) diironhexacarbonyl Complex: A Catalyst for Hydrogen Production

 

Karr, Derek; Mebi, Charles A.

Arkansas Tech University

 

The reaction of naphthalene-2-thiol and Fe₃(CO)₁₂ in THF under reflux conditions afforded the diiron carbonyl complex, [(m-naphthalene-2-thiolato)2Fe₂(CO)6] (1). Complex 1 was obtained as an orange solid in 80% yield. The iron cluster (1) has been characterized by infrared, UV-visible and proton NMR spectroscopy. The infrared spectrum of 1 recorded in dichloromethane contains three peaks at 2075, 2039 and 2001 cm-1 characteristic of stretching vibrational modes of terminal metal carbonyls. The spectroscopic data and elemental analysis are consistent with the presence of an Fe2(CO)6 cluster tethered to two naphthalene-2-thiolate ligands. We will report the redox properties of 1 determined by cyclic voltammetry. Cyclic voltammograms of 1 in the presence of acetic acid were obtained and will be presented. Compound 1 is shown to catalyze the electrochemical reduction of proton to molecular hydrogen.

 

 

2.     Comparison of Light Dependent and Light Independent DNA Repair Rates in UV Irradiated E. coli.

 

Sweet, Gary; Nelson, Lynda P.

University of Arkansas at Fort Smith

 

The high energy of UVa radiation is known to mutate DNA primarily through the formation of dimers. The E. coli bacterium possesses two separate mechanisms to cope with this environmental stress. This study uses two experiments to compare the two mechanisms in terms of efficiency using survival and growth rates as criteria. The hypothesis is since the light dependent mechanism has a constant source of energy and requires no cellular energy, it should proceed more efficiently (or maybe effectively?) than the competing mechanism. A series of E. coli cultures were exposed to UVa radiation and allowed to recover in light and dark conditions to test the hypothesis. The mechanisms were kept separate through the use of a chemical inhibitor, Okadaic Acid. The results showed that the light dependent mechanism was approximately 22% more effective in terms of cell survival and growth.

 

 

3.     Organics in Precipitation: Links to Carbonaceous Aerosols and Climate

Bridges, Gail L.; Gaffney, Jeffrey; Marley, Nancy

University of Arkansas at Little Rock

Aerosols and clouds can impact climate forcing by scattering and/or absorbing radiation. A major source of carbonaceous aerosols are secondary organic aerosols formed from oxidation of biogenic volatile organic emissions that have seasonal dependences, and are likely to increase with climate change (i.e. warmer, wetter climate with longer growing seasons). Wet deposition of the dissolved organic carbon may be a significant source of organics in surface waters thus affecting estuarine ecosystems. Much of the dissolved organic carbon in surface waters is from natural humic sources that include higher molecular weight humic acids and smaller molecular weight fulvic acids. Humic acids and fulvic acids contain hydrophobic and hydrophilic functional groups. The source of the smaller fulvic acids and larger humic acids into surface waters is not well documented. Fulvic and humic substances are found in soil, water, and sediments and have been thought to be primarily from microbi al degradation of plant debris. Total organic carbon (TOC) and dissolved organic carbon (DOC) for unfiltered rainwater and for .45 micron filtered is currently underway to examine TOC/ DOC in precipitation to evaluate the atmospheric removal of carbon. Black carbons (soots) that are strong light absorbers are also present and are monitored during rain events to evaluate BC removal rates and are expected to be removed during filtration. Further ultrafiltration with stirred cells allows sized isolates to be chemically characterized using UV-visible-NIR and FTIR spectroscopy, XRF for trace element scanning, and LC-MS for trace organic species molecular identification. Precipitation and aerosol data is obtained at the UALR atmospheric observatory roof top site. This project is supported by the US DOE Atmospheric Systems Research program.

4.     Natural Radionuclides as indicators of atmospheric aerosol washout

Begum, Mahbuba; Gaffney, Jeffrey S.; Marley, Nancy A.

University of Arkansas at Little Rock

Naturally occurring radionuclides 7Be, 210Pb and its daughters 210Bi and 210Po are useful tracers of fine atmospheric aerosol processes such as tropospheric transport and removal that determine aerosol residence times. 7Be (t ½ =53 days) is produced in the upper troposphere and lower stratosphere by the interaction of cosmogenic particles such as carbon, oxygen and nitrogen and once it is formed attaches to existing atmospheric aerosols that are submicron in size. The secondary radionuclide 210Pb (t ½ =22.3 years) is produced by radioactive decay from gaseous 222Rn which is sourced from land surfaces via 238U decay in continental surface air masses tags lower atmospheric particles such as soots. Carbonaceous soots (black carbon) have been observed to have slow hygroscopic growth and are of interest due to their strong absorption properties. To better evaluate aerosol removal during rain events, size-fractionated aerosol samples were taken on the roof of the Science Laboratory building (SCLB) at University of Arkansas at Little Rock (UALR) using slotted impactors and high volume aerosol samplers and gamma counting used to determine the activity of 7Be and 210Pb. The median aerodynamic diameter for both 7Be and 210Pb was observed in the submicron region (0.3µ) with minimal growth to larger sizes during rain events consistent with slow removal of black carbon (BC). These results are discussed in terms of the implications for biomass burning and diesel engine use on climate change. This project is supported by the U.S. DOE Atmospheric Systems Research program.

5.     Characterization of Secondary Organic Aerosol (SOA) formed by the reaction of β-Caryophyllene coated soot and Ozone: Climate Impact

Sarkar, Amrita; Gaffney, Jeffrey A.; Marley, Nancy A.

University of Arkansas at Little Rock

Characterization of Secondary Organic Aerosol (SOA) formed by the reaction of β-Caryophyllene coated soot and Ozone: Climate Impact Amrita Sarkar, Jeffrey S. Gaffney, Nancy A. Marley University of Arkansas at Little Rock Diesel soot (black carbon,BC) is an important light absorbing aerosol component in atmosphere that can cause tropospheric heating. Laboratory studies have found it to be unreactive to ozone at ambient temperatures. Low Uptake Coefficient i.e., γ 300 K = 2× 10-7 of soot-O3 reaction indicates low probability of irreversible O3 loss from gas phase to surface-adsorbed product (Particle phase) which shows clearly that at low temperature soot is not reactive with atmospheric oxidants. In contrast, sesquiterpenes (SQT) such as β-caryophyllene (C15H24) which are emitted from vegetation are extremely reactive with ozone. For example, β-caryophyllene residence time in atmosphere is only 2 min in the presence of 60 ppb ozone. It is expected to be a significant source of biogenic secondary organic aerosols. These oxidized products may condense onto soot particles, and a question arises is what will be there portioning between the soot surface, vapor phase, and aqueous aerosol phases . LC-MS, FTIR and UV-Vis spectrosopies are being used to study the β-Caryophyllene-Dark Ozonolysis reaction at low ozone levels (40-50 ppb). Products identified include low molecular weight highly volatile and water soluble products such as formaldehyde, acetaldehyde, acetone, and acetic acid. Also identified are high molecular weight components (350 Da) with lower water solublity and vapor pressures .The SOA coatings are being evaluated to determine their hygroscopicity. As these compounds absorb in the IR and UV-Vis they can add to radiative forcing and need to be better understood for climate modeling. This work is supported by the U.S. DOE Atmospheric Systems Research program.

6.     Evaluation of Aluminum Corrosion

Shepherd, Kyle M.; Hardcastle, Franklin D.

Arkansas Tech University

A trucking company located in Russellville, Arkansas reported problems with corrosion and pitting of the aluminum flooring of their newer model refrigeration trailers used to transport poultry. The older model trailers did not suffer from this corrosion problem although the aluminum and insulation from the newer and older trucks appear to be of the same composition. The damage was characteristic of typical chloride pitting and corrosion which may have been caused by the magnesium chloride used to de-ice roads. Samples of corroded aluminum flooring and contact insulation were collected and analyzed by X-ray photoelectron spectroscopy (XPS), energy dispersive X-ray spectroscopy (EDX), infrared spectroscopy (FTIR), and Raman spectroscopy.

7.     Optically Sensing Mercury Ions Using Carbon Nanotubes

Kamel, Azhar; Deloach, Devethia; Zhao, Wei

University of Arkansas at Little Rock

Solvated mercury ions Hg+2 are considered as one of the stable forms of mercury that lead the increasing threat to the environment and human health. In this study, single-walled carbon nanotubes (SWNTs) encased with surfactants were used to detect Hg+2 in aqueous solutions based on their unique near infrared (NIR) optical properties. Double stranded DNA (dsDNA), single stranded DNA (AT)10 and sodium dodecyl sulfate (SDS) were used to disperse SWNTs to form stable suspensions. The suspensions were then used to monitor the response of SWNTs to various concentrations of mercuric ions. The results showed a systematic SWNT peak shift with the increase of Hg2+ concentration in both dsDNA-SWNT suspension and (AT)10-SWNT suspension. On the other hand, no peak shift was observed in SDS-SWNT suspension. Instead, the SWNT NIR spectral intensity was suppressed, which showed reaction time- and Hg2+ concentration-dependent spectral changes. The peak shift may be due to direct interaction between mercury ion and DNA strand forming metal-base complexes. The response of SDS-SWNTs to Hg+2 ions may be due to the direct redox reaction between SWNTs and Hg+2 ions. Further experiments using different metal ions indicated that dsDNA-SWNTs had high selectivity to mercury ion over other metal ions, an important feature for practical sensing applications.

8.     Synthesis and Characterization of Polymer-tethered Fullerenes (PTFs)

Eller, Jonathan R.; Ali, Shariq; Alexander, Amy M.; Moore, Josh A.; Berry, Brian C.

University of Arkansas at Little Rock

A series of bromine-terminated polystyrenes of varying molecular weights ranging from 500-15000 were synthesized using atom transfer radical polymerization (ATRP). Polymer tethered fullerenes (PTFs) were then prepared by coupling the synthesized polystyrenes to fullerene via atom transfer radical addition (ATRA). The resulting PTFs were analyzed by GPC, NMR, FT-IR, and TGA to determine optimum reaction conditions. The as-synthesized PTFs were found to contain a mixture of mono- and di-adducts that were further purified via fractionation. Thin films of the mono-tethered fullerenes were prepared and annealed under various conditions and examined using AFM, TEM and SEM.

9.     Synthesis and characterization of polymer-tethered nanoparticles (PTNPs) using amine-terminated polystyrene

Alexander, Amy M.; Eller, Jonathan R.; Berry, Brian C.

University of Arkansas at Little Rock

Fullerenes were coupled with amine-terminated polystyrene via a simple addition reaction. Reagent ratios and reaction times were varied to establish their influence on mono- versus poly-adducted product yield. While toluene was employed as the primary solvent in the synthesis, co-solvents such as pyridine, DMF, and DMSO were incorporated in various ratios to determine which results in optimum yields of the desired mono-adducted product. The resultant PTNPs were analyzed by TGA, GPC, and UV-Vis spectroscopy to determine the number of adducts. The reaction conditions were found to directly impact the number of adducts and overall yield.

10.  Molecular Structure of fac-aquadichlorotris(dimethylsulfoxide)ruthenium(II)

Foster, Les; Hardin, Jennifer; Draganjac, Mark

Arkansas State University

Yellow crystals isolated from the reaction of cis-Ru(dmso)₄C_l2 with K₂CS₃ in CH₂C_l2 gave an unanticipated product, fac-[Ru(OH2)Cl2(dmso)3], I.  Though compound I has been studied previously, the single crystal structure had not been reported.  I crystallizes in the monoclinic space group C2/c, cell dimensions: a = 15.2893(11), b = 7.8993(5), c = 49.552(3) Å, α = 90, β = 90.131(2), γ = 90°, Z = 8, V = 5984.6(8) Å3, with two Ru complexes in the asymmetric unit of the crystal structure and 0.125 occupancy water of hydration.  The dmso ligands are S-bound with Ru-S distances of 2.2412(9), 2.2650(10) and 2.2780(10) Å for complex 1 and 2.2467(10), 2.2595(10) and 2.2801(9) Å for complex 2, respectively.  The shorter Ru-S distances are for the dmso ligand trans to H2O ligand.  Similar bond lengths are observed for the cis-Ru(dmso)4Cl2 complex.

11.  Development of Mathematical Models for Dielectric Heating in Aqueous Environments

Bejamin, Earl; Young, Michael; Benjamin, Ellis T.

Arkansas State University

Dielectric heating, using microwave radiation at 2450 MHz, is currently used for a number of processes such as food preparation, bacterial deactivation, water disinfection, and chemical synthesis. Dielectric heating has been shown to be more efficient than conventional heating which involves significant heat loss to the environment. While studies have shown that the solvent’s dielectric constant play a critical role in the heating process, few studies have analyzed the effect of ionic compounds on dielectric heating in an aqueous environment. The focus of this study is to analyze the physical characteristics of an aqueous environment both with and without ionic compounds present in both multimode and monomode microwave ovens. Parameters such as temperature change, heat change, and solvent loss were used to develop simple mathematical models for dielectric heating in aqueous environments.

12.  Computational Analysis of Surfactant Binding to Bacterial Membrane Proteins

Benjamin, Ellis T.; Young, Michael; Benjamin, Earl

Arkansas State University

The spread of pathogenic microbes such as Methicillin-resistant Staphylococcus aureus (MRSA) and E. coli O157:H7 is a growing public health issue. For centuries surfactants (soaps) have been considered as the first defense against the spread of these pathogenic agents. Although antimicrobial compounds such as Triclosan are able to increase antimicrobial activity of these soaps, few studies have examined the natural microbiocidal activity of commercial and noncommercial surfactants. This study examines the binding energies of various surfactants including oleic acid and myristic acid to bacterial membrane structures including phospholipids and membrane bound proteins including OMPX and Iron Transporter FecA using HEX 5.0® to identify possible biocidal mechanisms.

13.  Nitrate and nitrite in spinach, romaine, cilantro, and napa cabbage

Willis, Mackenzie; Huang, Jimming

University of Arkansas at Monticello

Nitric oxide (NO) has numerous important functions in mammalian systems. It plays a major role in maintaining normal blood flow and arterial pressure. Nitrite and nitrate are the major oxidative products of NO. However, in recent years, scientists discovered that nitrite also represents a major storage form of NO. Nitrite from vegetables can be bio-activated and/or recycled to form NO under hypoxic conditions. It is also reported recently that dietary nitrate can reduce blood pressure in healthy volunteers. Nitrate from vegetables, whether cooked or uncooked, is absorbed very effectively, resulting in an absolute nitrate bio-availability of around 100%. We investigate nitrate and nitrite contents in spinach, romaine, cilantro, and napa cabbage from supermarket in Arkansas. Those vegetables with high nitrate levels will be the potential food to help treat high blood pressure. Nitrate concentration is determined by electrochemical method with nitrate ion selective electrode, while nitrite concentration is determined by spectrophotometric method. Our results show that nitrate level in cilantro, spinach, romaine, and napa cabbage are 1.89 mg/g, 2.24 mg/g, 2.30 mg/g, and 2.08 mg/g respectively; while the nitrite levels are all below the detection limit at the day when samples were prepared (below 3 μM in sample solution). The nitrate level in romaine and napa cabbage decreased to 1.56 mg/g and 1.21 mg/g respectively after one day. The nitrate level in cilantro and spinach decreased to 0.85 mg/g and 1.38 mg/g respectively after one week; while nitrite level in cilantro and spinach increased to 0.56 mg/g and 0.86 mg/g after one week in 4 oC. These results suggest some of nitrate were reduced to nitrite by enzymes in these vegetables during storage. Our preliminary results show that nitrate levels are much higher that nitrite levels in these vegetables. So, nitrate from vegetables probably is a more important storage form of NO and play important physiological role in human body, especially in maintaining normal blood pressure. *To whom correspondence should be address, Ph: 870-460-1866, Fax: 870-460-1316, Email: huang@uamont.edu, This project is supported by grant from Arkansas Space Grant Consortium. Dr. Juan Serna helped in finding software to fit data to obtain nitrate concentration.

14.  High Performance Liquid Chromatography- Mass Spectrometric Analysis of Wild Animal Bile Acids

Nasini, Udaya B.; Ghosh, Anindya; Shaikh, Ali U.

University of Arkansas at Little Rock

Bile acids are water- soluble steroids and biological emulsions useful in the digestion process of food. The conjugated bile acids play a major role in fat metabolism. Deconjugation of conjugated bile acids by bacterial enzymes produces free bile acids in the colon. These free bile acids are converted to secondary bile acids by bacterial flora. About 5% of cholesterol is excreted as bile acids in animal and human feces.1 It is postulated that a difference in the molecular forms of various bile acids and their concentration profiles exists among various animals, depending upon their food habits. Consequently, it may be possible to distinguish various types of carnivorous wild animals by determining the bile acid profiles in their feces. A rapid, sensitive and highly specific high-performance liquid chromatography-electrospray mass spectrometry method has been developed for the determination of bile acid profiles in the scat samples of wild a nimals. Bile acid samples were extracted from scat by solid phase extraction. Mixture of standard unconjugated as well as glycine and taurine conjugated bile acids were separated and detection was performed using ESI-MS/MS.5 Method involves, gradient reverse phase separation with methanol/0.4 M ammonium acetate (60/40, v/v) containing 0.1% formic acid on a C18 column and is suitable for detection and quantification.6 The LC-MS method is more sensitive than the GC-MS methods described earlier.

15.  Theoretical Molecular Modeling for Melanine-Metal Ion Complex in Substantia Nigra of Parkinson’s Disease Patients

Armstrong, Jazsmine A.¹; Thotakura, Sushma X.²; Griffin, Billy O.²; Hahn, F. I.¹; Darsey, Jerry A.²

¹Philander Smith College

²University of Arkansas at Little Rock

Recent studies have shown that metal ions play an important role in increasing the relative amount of oxidative neuronal damage found in the Substantia Nigra of Parkinson’s disease patients. When metal ions are particularly interacting with neuromelanin, the degeneration of melanized dopaminergic neurons in the brain cell can be promoted due to liquid peroxidation initiated by hydroxyl free radicals (.OH). Here, molecular modeling for the interactions between the neuromelanin and metal ions (e.g., iron, copper, etc.) is performed to obtain optimized molecular structures and properties of the melanin-metal complexes to better understand an increase in the toxic oxygen radicals and an accelerated rate of neuronal degeneration in the patients. In this project, SYBYL software is utilized to compare the reactions between a control Substantia Nigra and that which has been infiltrated with iron and copper.

16.  Synthesis of polyurethane in expanded carbon dioxide solvents (CXLs) using soluble tin catalysts

Gartia, Yashraj; Ghosh, Anindya; Munshi, Pradip; Berry, Brian

University of Arkansas at Little Rock

Polyurethanes are a material that is used in large amount in different forms ranging from rigid foams, light weight foams, elastomers, adhesive, and coatings. Large scale production of polyurethanes involve huge amount of commonly used organic solvents which have potential health hazards. In this study, carbon dioxide expanded solvents (CXLs) is being used as an alternative green solvent where a common organic solvent is expanded with compressed carbon dioxide (major part). Besides taking advantage of greenness, CXLs can be designed to have variable polarity, which are suitable for performing reactions, dissolution of materials, extractions, and separations. 1, 3-dichloro-1, 1, 3, 3-tetraalkyldistannoxanes complexes which are highly soluble in CXLs are used as catalyst for the present study for synthesis of polyurethanes. Different catalysts showed varying amount of reactivity depending on their solubility in CXLs. The kinetics of polyurethane synthesis using CXLs was performed and compared with the rate of polymerization in pure organic solvent namely, dimethyl formamide. The polyurethanes were characterized using FT-IR, 1H-NMR and thermo gravimetric analysis (TGA). Molecular weights and polydispersity index (PDI) were determined using gel permeation chromatography (GPC). Compared to neat organic solvent, rate of polyurethane synthesis was found to be faster in CXLs using chlorostannoxane catalyst.

17.  Substituted N-Confused Tetraphenylporphyrins: Synthesis and Cobalt Insertion

Martin, Zachary; Watson, C. Todd

University of Arkansas at Fort Smith

Mono- and di-substituted N-confused tetraphenyl porphyrin macrocycles, porphyrin ligands in which one of the pyrrole rings is inverted resulting in an NNNC porphyrin center, were synthesized. The reaction involved the methanesulfonic acid catalyzed condensation of pyrrole with one of two substituted benzaldehydes, either 2,6-dichlorobenzaldehyde or p-methoxybenzaldehyde. Oxidation of the condensation product to the final aromatic product was carried out using tetrachloro-1,4-benzoquinone (TCQ). Spectroscopic data provided evidence for the successful synthesis of both N-confused-tetra(2,6-dichlorophenyl)porphyrin and N-confused-tetra(p-methoxyphenyl)porphyrin. Following the creation these N-confused macrocycles the insertion of the transition metal cobalt (II) was attempted.

18.  Synthesis and Characterization of Tanninsulfonic Acid Doped Polyaniline/Metal Oxide Composites for use in Solar Cells

Bairi, Venugopal; Warford, Brock A.; Saini, Viney; Bourdo, Shawn E.; Viswanathan, Tito

University of Arkansas at Little Rock

Intrinsically conducting polymers have been used as hole conducting layers in various kinds of the organic solar cells. Photovoltaic (PV) device efficiencies of greater than 3% have been achieved in hybrid organic solar cells in the last decade by using polyaniline as an intermediate layer. Polyaniline prepared by a self stabilized dispersion polymerization (SSDP) method exhibits good conductivity values of around 20-40 S/cm. We have prepared tanninsulfonic acid doped polyaniline (TANI-PANI) composites in view of preparing metal oxide complexed composites due to the presence of o-catechol in tannin. The presence of metal oxides may enhance the photovoltaic effect and increase the efficiency of solar cells. The products have been characterized by UV-visible and IR spectroscopy. Their electrical properties were determined by bulk conductivity and thin film surface resistivity measurements. The results of these studies will be presented along with data from hybrid (organic/inorganic) PV devices incorporating these materials.

19.  Highly Active Co(III) Complex of Tetraamidomacrocyclic Ligand for Cyclic Carbonate Synthesis

Ramidi, Punnamchandar; Ghosh, Anindya

University of Arkansas at Little Rock

Carbon dioxide (CO₂), a common green house gas, is produced in large quantities by human activities in addition to other natural sources. Use of CO₂ may potentially end the use of common organic solvents and other toxic C1 synthons, such as phosgene, carbon monoxide, and isocyanate. A better knowledge of the coordination chemistry of CO₂ to transition metal centers might provide us with an understanding of the possibilities of incorporating CO₂ in the discrete organic monomers to synthesize useful chemicals. In this context, the reaction of aliphatic or aromatic epoxides with CO₂ to produce cyclic carbonate in an environmentally friendly method is an important area of research. A cyclic carbonate is a colorless, odorless, low toxicity and biodegradable molecule which can be used as benign solvent and making industrially important chemicals and polymers. Various cyclic carbonates were synthesized with yield up to 100% and turn over frequency (TOF ) up to 350 h-1 using CO₂ and a range of aromatic or aliphatic epoxides in presence of a cobalt(III) complex of tetraamidomacrocyclic ligand. A co-catalyst (either organic amines or organic halide salts) along with the metal catalyst was used to obtain enhanced activity of cyclic carbonate synthesis. The reaction was performed under relatively low CO₂ pressure (300 psi) and temperature and also without using any organic solvent. Besides high reactivity, the catalyst is stable under the reaction condition and does not lose activity.

20.  Computational Study of Molecular Hydrogen Physisorption on Activated Heterocyclic Isoreticular Metal-Organic Frameworks

Carranza, Arturo; Doria, William J.

University of the Ozarks

With demands for more environmentally-friendly fueling methods on the rise, research for materials offering efficient hydrogen storage has received increasing attention. Isoreticular metal-organic frameworks (IRMOFs) are viewed as a promising group of materials in which several advances have been recently made. In this study, PW91density-functional theory calculations were used to determine the effects of activation groups and heterocyclic frameworks in the equilibrium geometry, atomic positions, and binding energies of IRMOF-hydrogen systems. In order to provide expedited and accurate results, 6-311++G** basis set was used in conjunction with Bernardi’s counterpoise correction that accounts for molecular interaction difference of separate total energies. In addition, the fidelity of the PW91 calculations with applied counterpoise corrections was assessed by comparing the results of benzene, IRMOF-1, and IRMOF-8 to the results attained by othe r research groups. It was noted that hydrogen’s affinity toward a framework is closely related to the number of electronegative atoms in the ring of the framework. Hydrogen had a higher affinity for 5-membered ring frameworks than other molecules tested. Methylation and amination of a framework resulted in much higher hydrogen affinity, but as the molecule became saturated with activation groups, amine groups were generally preferred over methyl groups.

 

Physics Posters

 

1.     Assessing the Vertical Accuracy of Arkansas Five-Meter Digital Elevation Model for Different Physiographic Regions

 

Weih, Robert C. Jr

University of Arkansas at Monticello

 

Digital Elevation Models (DEMs) represents the average elevation of the earth’s surface for a specific area. Scientists and decision makers have used DEMs to address questions relating to the earth’s landscape. This study assessed the vertical accuracy of 2006 Arkansas 5-meter DEM dataset produced photogrammetrically for the state of Arkansas for three physiographic regions in Arkansas that represented a variation of elevations. The vertical accuracy of the DEM datasets was assessed by comparing their elevations to elevations collected using surveying carrier phase GPS. To make comparisons between physiographic regions, Paired T-test and Absolute Mean Range Values (AMRVs) were computed to normalize the elevation error. The results of the study revealed that 5-meter DEMs was not statistical different from the true elevation for the state, but statically different for the Ouachita Mountains region of the state.

 

 

2.     Pattern Speed Estimates of Barred Galaxies from CINGS: A Connection Between Central Dark Halo Concentration and SMBH Mass?

 

Treuthardt, Patrick M.¹; Seigar, Marc S.¹; Salo, Heikki²

¹University of Arkansas at Little Rock

²University of Oulu, Finland

 

We present preliminary results of an investigation into the potential relationship between central dark halo concentration and supermassive black hole (SMBH) mass in the nuclei of disk galaxies.  Barred disk galaxies with bar pattern speeds deemed “fast” exist in halos with a low central concentration, since the bar rotation would rapidly decrease due to dynamical friction with the halo.  We estimated the pattern speeds of a sample of barred spiral galaxies from the Carnegie-Irvine Nearby Galaxy Survey (CINGS) by matching inelastically colliding gas particle simulations to B-band morphologies using near-infrared Ks-band images to define the gravitational potentials.  The results from these models are compared to the SMBH mass of the sample galaxies.

 

 

3.     Behavior of a Helmholtz Resonator Driven at High Amplitudes

Morris, Dustin; Slaton, William V.

University of Central Arkansas

The acoustic behavior of a Helmholtz resonator was studied when driven by a compressed air source. The resonator consists of a 55 gallon drum with 4-inch diameter necks of different lengths. Compressed air from a 0-15 psi regulator is introduced into the resonator using an electronic valve controlled by a signal generator. A pressure sensor was used to study the acoustic behavior of the resonator as it was driven over the resonance frequency with the compressed air source. By closely examining the resonant peaks, the quality factor of the system could be determined for different drive pressures and resonance frequency. The measured resonance frequencies are compared to two theoretical models. The resonator’s quality factor (energy stored in resonance / energy lost per cycle) is shown to decrease with drive amplitude indicating increased losses with higher amplitude.

4.     The Effect of a Helmholtz Resonator’s Neck Geometry on the Aero-Acoustic Excitation of Resonance

Niskikawa, Asami; Slaton, William V.

University of Central Arkansas

The aero-acoustic excitation of a Helmholtz resonator with different neck geometries has been examined with an improved measurement technique. A Helmholtz resonator consists of a volume connected to a duct and has a well defined resonance frequency which depends on the length of the duct, the volume of the resonator and the cross-sectional area of the duct. In the system used during this experiment, two Helmholtz resonators have been positioned at opposite sides of a junction in a wind tunnel. The air speed in the wind tunnel can be varied over the range 0 to 28 m/s. The air flowing over the junction openings to the Helmholtz resonators can excite the acoustic resonance of the system. This is similar to blowing over an empty bottle’s opening and creating a tone. The excitation of the resonator’s as a function of flow speed in the wind tunnel has been recorded. The effect of the resonator’s geometry has been seen in the measured acoustic amplitude and frequency in the resonator and will be presented.

5.     Investigating the Structural Optimization of Nano-Antennas

Crain, Stephen G.; El-Shenawee, Magda

University of Arkansas

Research has shown that noble metals, such as gold and silver, can sustain surface plasmon polariton oscillations at the boundary between the metal and a dielectric when excited at an optical frequency. The shape of these metals directly influences the resonance and the field enhancement of the nano-antenna. To be able to engineer nano-antennas for specific applications, the effects of the shape needs to be investigated. However, fabrication of the nano-antennas is time consuming and expensive. To quickly and inexpensively investigate the nano-antennas, computer simulations will be run to compute the plasmon resonance, local field enhancement, and far field characteristics for four types of nano-antennas. Nano-rod, bowtie, nano-sphere, and double bowtie nano-antennas will all be simulated. Based on the results of the simulation, a comparison will be made between the responses and the shapes of the antennas, resulting in a guide for determ ining the optimal structure for the nano-antennas for different applications.

6.     Carbonaceous Aerosol Impacts on Planetary Boundary Layer (PBL) Evolution

Marchany-Rivera, Angie; Gaffney, Jeffrey S.; Marley, Nancy A.

University of Arkansas at Little Rock

A major uncertainty in climate forcing is how the local and regional distributions of natural and anthropogenic tropospheric aerosols affect atmospheric planetary boundary layer (PBL) dynamics. While the PBL contains most of the aerosol and water vapor in the atmosphere and thus has a major influence on radiative forcing, the large variability in aerosol chemical and physical properties leads to significant difficulties in modeling their overall contribution to regional and global radiative fluxes (IPCC 2007). Aerosols derived from primary and secondary sources that are submicron in size are of particular interest as they tend to remain dispersed rather than gravitationally settling or condensing onto existing aerosol surfaces. Aerosols that are strongly absorbing of solar and thermal radiation are of interest as they can lead to atmospheric heating (i.e. black carbon, BC). Lifetimes of carbonaceous aerosols are strongly dependent on wet deposit ion, for this reason removal measurements are correlated with meteorological variables such as relative humidity, temperature, wind, and PBL depth, as well as with the chemical variable, dissolved organic carbon (DOC) concentrations. By performing back-trajectories of air transport and using elemental tracers (e.g. K, P, Ca, Cl, and Zn) aerosol sources can be shown to be dominated by either biomass burning or diesel soot emissions. The wavelength (λ) dependence of aerosol absorption, the Angstrom absorption exponent, is used to identify UV absorbing organics in the aerosol. The depth of the PBL during rain and non-rain events as a controlling factor in the transfer of moisture, aerosols and momentum between the atmosphere and the Earth’s surface is being explored. This project is supported by the U.S. DOE Atmospheric Systems Research program.

7.     High Optical Absorption of Indium Sulfide Nanorod Arrays Formed by Glancing Angle Deposition

Cazsizoglu, Mehmet F.¹; Engelken, Robert²; Seo, Hye-Won¹; Karabacak, Tansel¹

¹University of Arkansas at Little Rock

²Arkansas State University

Indium (III) sulfide has recently attracted much attention due to its potential in optical sensors as a photoconducting material, and in photovoltaic applications as a wide bandgap material. On the other hand, optical absorption properties are key parameters in developing photosensitive photodetectors and efficient solar cells. In this work, we show that indium sulfide nanorod arrays produced by the glancing angle deposition technique have superior absorption and low reflectance properties compared to conventional flat thin film counterparts. We observed an optical absorption value of approximately 96% for nanorods at wavelengths < 500 nm in contrast to 79% for conventional amorphous-to-polycrystalline thin films of indium sulfide. A superior photoconductivity (PC) response as high as about 40% (change in resistance upon illumination) was also observed in nanorod samples. This is mainly believed to be due to their high optical absorption, wher eas only less than 1% PC change was detected in conventional thin films. We give a preliminary description of the enhanced light absorption properties of the nanorods by using the Shirley-George Model which predicts diffusion of light as a function of the roughness of the surface.

 

 

8.     Optical Characterization of Ag Doped Ply (Vinyl Alcohol Films)

 

Jabbar, Wasmaa; Habubi, Nadir F.; Chiad, Sami S.

Al Mustasiriyah University, Baghdad

Ag doped PVA films were prepared by casting method in order to study the effect of Ag on the optical properties of PVA using UV/VIS spectroscopy. This research includes the estimation of, kind of transition, the value of the optical energy gap, and the optical constants such as refractive index, extinction coefficient of Ag doped PVA films, the refractive index dispersion curve of the films which obey the single oscillator model and optical dispersion parameters E0 and Ed developed by wimple-Didomenco were calculated also.