Abstracts for the 2003 Joint Science
Symposium for Student Research







Abstracts from the Department of Biology

Nonoxynol-9 immediately immobilizes Xenopus laevis sperm in a video microscopy sperm motility assay

Melissa Breedlove

Nonoxynol-9 is the most common spermicide on the market today.  It is a non-ionic surfactant that immediately lyses sperm, causing a premature acrosome reaction and killing sperm cells.   Because of its mechanism of action, nonoxynol-9 is effective against the sperm of many mammals, including rabbits, boars, bulls and dogs.  However, susceptibility to nonoxynol-9 varies widely between species.  I have developed a simple sperm motility assay to evaluate the spermicidal effects of nonoxynol-9 on Xenopus laevis.  Sperm were obtained from isolated testes and exposed to varying concentrations of over-the-counter spermicidal gel (active ingredient: nonoxynol-9).  Sperm motility was measured by video microscopy within five minutes of exposure.  Nonoxynol-9 immediately and reliably immobilized Xenopus laevis sperm.

Hemagglutination capabilities of stability mutant reoviruses under stressful conditions as an indication of cell interaction

Erin Brockway, Jennifer Kawwass, and Dave Wessner

Past research has resulted in the isolation of various reovirus stability mutants.  Studies confirm that single amino acid changes in an outer capsid protein can increase the overall resistance of the reovirus to a number of virucidal agents.  In particular, Wessner and Fields (1993) isolated a series of mutant reoviral strains (T3DEtr) that display an increased resistance to ethanol. The mutations have been identified as single-point mutations in the M2 gene, resulting in single amino acid alterations in the μ1 outer capsid protein gene product.  The μ1 protein has been further associated with additional viral properties, including viral entry, disassembly, and cytoplasm penetration.  It is therefore hypothesized that the M2 stability mutants may possess altered pathogenic abilities.  In this study, we investigated the cell interaction capabilities of these mutant viruses as demonstrated by the ability of mutant virions to agglutinate red blood cells under various stressful conditions, particularly treatment with heat and ethanol.

A role for fibroblast growth factor in Xenopus retinal neuron dendritic arborization

Jordan Case and Barbara Lom

During synapse formation developing neurons extend elaborate dendritic arbors that are regulated by many factors.   We investigated the possibility that fibroblast growth factor receptors mediate retinal ganglion cell dendritic outgrowth in Xenopus retinal ganglion cells (RGCs).  Xenopus RGCs express fibroblast growth factor receptors and FGFRs are known to play important roles in RGC axon extension and recognition of the target region.   Recent experiments indicate a role for FGF in RGC dendritic arborization because exogenous applications of FGF enhance RGC dendritic branching.  To investigate the possibility that FGFRs mediate RGC dendritic outgrowth in Xenopus RGCs, we microinjected the pharmacological FGFR inhibitor DMBI into the retinas at the onset of dendritic development.  RGCs were specifically labeled by retrograde rhodamine dextran labeling via microinjected into the optic tectum, where RGC axons terminate.  RGC dendritic morphology was then assessed in vivo by fluorescence microscopy.  Dendritic arborization was evaluated by counting the number of primary branches and dendritic branches, and by measuring the total dendritic length and cell soma size.  Our experiments indicate that inhibiting FGFRs may enhance dendrite initiation, branching, and outgrowth.

Characterizing GCP170/golgin160 localization in HeLa cells by indirect immunofluorescence microscopy.

Mike Chase

The Golgi apparatus is the organelle responsible for both intracellular and extra cellular protein trafficking. Comprised of a cis-golgi network, cis, medial, and trans membrane compartments, and a trans-golgi network, the structure of the Golgi apparatus is maintained by a series of proteins.  One such family of proteins is the Golgin protein family.  These proteins were identified in patients suffering from autoimmune diseases because their bodies created auto-antigens against Golgin proteins.  GCP170 is a member of the Golgin protein family and is thought to play a role in the maintenance of Golgi structure. A GCP170 construct was created with a GFP tag on the N terminal end of the construct to be used in transient transfections into HeLa cells.  A known Golgi protein, GM130, and endogenous GCP170 will be used as immunofluorescence markers.  Colocalization attempts between GM130 and GFP GCP170 will help characterize protein locality and function in the Golgi.

Xenopus laevis embryos are sensitive to malathion’s teratogenic effects during third day of development

Diana C. Chemotti, Christopher Paradise, and Barbara Lom

Malathion is an organophosphorus insecticide often sprayed on aquatic habitats to target mosquitoes.  A Frog Embryo Teratogen Assay: Xenopus (FETAX) was used to investigate the possibly teratogenous effects of malathion on African claw-toed frog (Xenopus) embryos as a model amphibian species.  Xenopus embryos were reared in concentrations of 0.1 and 0.25 mg/L for the first day (0-24 hours), second day (24-48), third day (48-72), or all three days (0-72) of the experiment.  Other embryos were also reared in separate control solutions of 0.05 % acetone and 20% Steinberg’s solution.  The angle of each tadpole’s anterior-posterior axis was measured by tracing the axis onto a transparency from a digital photograph on a computer screen.  The axis angles of the groups of tadpoles exposed to malathion during the third day (48-72) of the experiment and all three days (0-72) of the experiment differed significantly at both concentrations from the controls with a p values < 0.001.  The axis angles of the tadpoles exposed the first (0-24) and second (24-48) days of the experiment did not differ statistically from the controls.  During the sensitive window of 48 to 72 hours, the tadpoles exposed to 0.25 mg/L of malathion were on average bent more severely (65.6 degrees) than the tadpoles exposed to 0.1 mg/L of malathion (22.0 degrees).

Using artificial nest cups to determine settlement rules in a loosely colonial swallow

Ned Conway, Mark Stanback, Ana Gabela

To determine whether barn swallows (Hirundo rustica) maximize inter-nest distances as they settle, we studied nest initiation patterns at an established colony at which old nests were removed and artificial nest cups were attached at regular intervals (122 cm) to the smooth concrete underside of a pier.  Additionally, because the nest cups were situated in two rows 122 cm apart and separated (visually) by a concrete beam, nests within a row were visible to one another but not to nests in the other row.  Contrary to our expectations, swallows did not demonstrate an aversion to nesting 122 cm from visible neighbors.  In 2003 we are reducing inter-cup distance to 61 cm.

Effects of the pesticide malathion on the development of zebrafish, Brachydanio rerio

Leslie Cook

Pesticides are important in agriculture for preventing crops from being eaten by insects; however, many pesticides have detrimental effects for non-target organisms.  Malathion is an organophosphorus pesticide that is used for mosquito control and is used for the Boll Weevil Eradication Program.  Malathion is lethal to adult zebrafish and to their embryos.  By exposing zebrafish embryos to non-lethal doses of malathion, the teratogenic effects of malathion can be classified and quantified.  I optimized methods for zebrafish embryo production and survival.  Zebrafish embryos were exposed to two different concentrations of malathion solution and two control solutions for five days after fertilization. Malathion exposure led to an earlier hatching time, shorter body length, and reduced eye diameters.  Malathion’s action as an acetylcholinesterase inhibitor and the metabolites of malathion are likely responsible for the teratogenic effects of malathion.

Seasonal body temperature variation in the painted turtle (Chrysemys picta)

Kristine L. Grayson and Michael E. Dorcas

For ectotherms, body temperature variation can have important impacts on many aspects of their biology, including activity, metabolism, and growth.  Unfortunately, little is known about temperature variation in most ectotherms, especially in free-ranging animals.  To measure body temperature (Tb) variation in a free-ranging ectotherm, we attached micro-dataloggers to the carapaces of painted turtles (Chrysemys picta) in a farm pond located in Davidson, NC.  Water and mud temperatures (Tw) were simultaneously monitored using other dataloggers.  We successfully recorded Tb variation in 18 turtles from September 2001 to April 2002 and 14 turtles from April 2002 to October 2002.  Body temperatures steadily decreased through the fall and basking events continued throughout the middle of December. Minimum yearly Tb (1 – 3 C) occurred on the same week (2 – 7 January 2002) for all turtles.  Body temperatures then steadily rose and basking resumed in February.  More basking events took place during the months of February and March than during other months of the year.  During the summer, turtles reached Tb’s similar to those achieved via basking during cooler months, apparently without leaving the water.  Mean minimum weekly Tb was significantly higher for females than for males and the mean maximum weekly Tb was significantly higher for males.  We suspect this difference is influenced by the significantly larger body sizes of female turtles.  Our research demonstrates the effectiveness of microdatalogger technology for measuring Tb variation in small reptiles and provides the first critical step in developing a more complete understanding of painted turtle thermal biology. 

Using microsatellites to examine the effects of urban development on pond-dwelling turtles.

Kristine L. Grayson, Peter J. Leese, David R. Wessner, and Michael E. Dorcas

Development and habitat fragmentation is fast becoming one of the greatest threats faced by wildlife.  As suitable habitats for species are reduced to smaller and smaller patches that are farther and farther apart, species become exposed to a host of problems associated with population fragmentation.  Because of this phenomenon populations are increasingly forced to rely on migration of individuals both to allow for mixing of genetic material and to found new populations, replacing ones that go extinct.  Freshwater, pond-dwelling turtles provide excellent models for studying the effects of habitat fragmentation on metapopulation dynamics.  Although these populations are restricted to aquatic environments, these turtles have been shown to migrate across terrestrial habitats.  We have begun a project to assess the genetic flow across fragmented populations of painted turtles (Chrysemys picta) in the vicinity of Davidson, N.C.  Our project will use a very powerful genetic technique, microsatellite DNA analysis, to examine the effects of development and habitat fragmentation on the genetic diversity of these animals.  Using microsatellite analysis, we will be able to quantify the relatedness of different populations (ponds) and estimate the amount of gene flow (migration) between populations.  Thus far we have successfully located the microsatellite primers and extracted DNA from turtle tail tip samples.  In addition, to developing a protocol for painted turtles, we hope to expand the project to include the Northern Dusky salamander, Desmognathus fuscus and possibly some common species of snakes. 

Studies on the determinants of species diversity patterns in small aquatic communities

Nicole Harlan, David Wessner and Christopher Paradise

We are performing a long-term study on aquatic, detritus-based treehole communities to examine the relationships among abiotic factors, microbial diversity, and insect diversity.  Variously sized mesocosms (two depths crossed with three diameters), designed to replicate treeholes, were placed on trees in the Davidson College Ecological Preserve and sampled for dissolved oxygen level (DO), insect diversity and abundance, and microbial diversity.  Microbial diversity is being determined by terminal restriction fragment (TRF) pattern analysis of water samples from treeholes.  Abiotic factors, such as habitat size and DO are known to affect diversity, and we hypothesize that high volume, surface area, and dissolved oxygen levels all lead to high species richness of microbes and insects.  Further, the interactions between microbes and insects should affect their variation and population density.  Data to date shows a correlation between large-surface area containers and high DO.  Shallow, small-diameter mesocosms are correlated to high larval densities, and low DO levels were also correlated with high density.  Species richness was greater in some shallow treeholes than in deep treeholes; this trend did not extend to all three surface area treatments.  These results are contrary to some of our predictions, but the long-term pattern may change as communities develop.  Microbial diversity is still being analyzed in the laboratory.  One hypothesis we are testing is that as microbes are consumed by insects, microbial diversity increases.  Methods for analyzing these relationships will be presented.

A survey of proteomics methods for classroom and laboratory teaching

John M. Kogoy and A. Malcolm Campbell

 Proteomics is one of the most important new fields of study in the postgenomic era. In order to bring the study of proteomics into the classroom and laboratory, we have been working on several related projects which explore the potential of proteomics in a teaching environment. Two of the projects involve the molecular visualization software VMD and Chime. Both programs are freely available and utilize three-dimensional protein structure data deposited at the Brookhaven Protein Databank (http://www.pdb.org). We have written user’s guides for each, and have created a template web page that can be used by students to script their own Chime-based web pages. For the third project, we attempted to streamline a procedure for crystallizing lysozyme from hen egg whites, using the vapor diffusion method of protein crystallization. As a result, we have written a detailed crystallization protocol for lysozyme, which explores the effects of boiling, freezing, differing solution contents, and adding reagents, on the success of crystallization. This protocol includes a brief history of the applications of crystallization, suggested background readings, and a teacher’s manual. It is intended that these projects will be the foundation for group investigations and laboratory projects in future biology courses. 

Proton pump and gap junction inhibitors cause situs inversus in Xenopus tadpoles

Jason Lake, Sheena Bossie, Rob Neuman, and Barbara Lom

Gradients of biologically active molecules defined early in development determine the left and right sides of the body. These asymmetrical molecular gradients are established after the formation of the dorsoventral and anteroposterior axes, prerequisites for proper left-right axis development. Intercellular communication via gap junctions along the dorsoventral axis has been identified as a source of left-right asymmetrical gene expression. Additionally, H+/K+-ATPase transporters have been linked to establishing asymmetric gene expression perhaps through the generation of an ion flux. The administration the gap junction inhibitor BaCl2 or the H+/K+-ATPase inhibitor omeprazole just after fertilization randomizes left-right patterning and cause situs inversus, a complete reversal of the normal left-right pattern, in about one third to one half of the treated tadpoles. We have adapted a protocol developed by Levin and Mercola (2002) to investigate asymmetrical axis formation using BaCl2 and omeprazole and have observed situs inversus.

Microhabitat selection and movement patterns of black rat snakes (Elaphe obsoleta) in the western Piedmont of North Carolina

Lisa C. Marks, Pierson Hill, Diana C. Chemotti, and Michael E. Dorcas

In March 2002 we began an investigation into the ecology of black rat snakes (Elaphe obsoleta) in Davidson, North Carolina.  We surgically implanted radio transmitters and tracked ten snakes twice a week.  When a snake was located, we recorded its location, habitat, microhabitat, behavior, position, exposure to the sun, and GPS coordinates.  We used a GIS to analyze home range size and activity patterns.  Preliminary results from the last twelve months indicate that the four most frequented microhabitats are underground (31%), in trees (19%), in fallen tree stumps (17%), and in “other” microhabitats including kudzu patches, barns, junk piles, and abandoned structures (21%).  We found snakes inside trees 9% of the time and on the surface 3% of the time.  When observed on the surface, snakes were crawling and extended approximately 50% of the time and coiled approximately 50% of the time.  We also observed that snakes frequented edge habitats, which may be related to optimizing basking and feeding opportunities.  During the active season, the maximum movement of any single snake was slightly over one kilometer.  We found the mean home range of female black rat snakes to be larger than the mean home range of males.  Continuation of this study will allow further investigation of black rat snake home ranges, microhabitat preferences and movement patterns. 

Comparing localization of the N-terminus of GCP 170 and p115

Kimberly Newton and Karen Bernd

The Golgi Apparatus  (GA) is part of the secretory pathway and is thus a vital organelle within the cell. The proteins localized within the GA help it to perform its necessary functions and maintain the structure of the GA. One such protein is GCP 170. GCP 170 was first identified because the autoantigens were found in patients suffering from autoimmune diseases. In this study the localization of the N-Terminus of GCP 170 was investigated. The construct GCP170 1-258 was created and tagged with GFP. The localization of the N-terminus was compared to endogenous GCP 170 as a control and p115 to determine localization in both HeLa and Cos7 cells.

Malaria in Sub-Saharan Africa and South America:  challenges, opportunities, and outlook for the future.

Erinn O’Laughlin and David R. Wessner

Malaria increasingly has become a worldwide problem.  Each year, the malaria parasites infect 300-500 million people and the disease kills about 1.5-2.7 million people per year.  Over 90% of these fatalities occur in Africa and the vast majority of these deaths are in African children.  Plasmodium falciparum, one of four malaria parasites, is the most lethal form and is responsible for the high mortality rates.  Malaria is spreading rapidly throughout the African highlands and other areas of low endemicity.  South America has also seen a resurgence of malaria in the past decade, especially in the Amazon region.  The rise in malaria in both of these regions can be attributed to several factors, especially drug resistance, behavior of the mosquito vector, human migration, and poor health care infrastructure.  Despite recent efforts at sequencing the genome of P. falciparum and developing a vaccine, the future of malaria control does not look promising for the developing world.  Until political stability and a working health care system are achieved, efforts at malaria control may be fruitless. 

Exploring the limitations of DNA microarray technology: a case study in quality control

Emily Oldham, Laurie Heyer and Malcolm Campbell

DNA microarrays are a powerful new technology that allows rapid, high-throughput analysis of genome-wide expression patterns.  To assess the accuracy and validity of this technology, PCR products of ten Saccharomyces cerevisiae genes were printed on glass slides in known concentrations. Ten pairs of oligonucleotide probes were designed with limited non-target binding, and experimental ratios were compared to predicted values.  Surprising gene-dependent ratios were observed; when all ratios should have been precisely 1:1, some genes displayed characteristic ratio profiles.  Alternative hybridization methods failed to correct all ratios to 1:1.  Sources of experimental error in this multi-step process were documented.  Prior to data exploration, researchers must either demonstrate that no aberrant genes are present, or identify aberrant genes and eliminate them from the study.  A range of significance for ratio values must be determined prior to investigation for each microarray application.  My findings indicate that future DNA microarray experiments must include more rigorous controls. 

Exploring the use of plasmids in DNA microarray technology

B. Daniel Pierce and A. Malcolm Campbell

Using microarrays for high-throughput DNA detection is one of the fastest growing fields in biology today. However, the field is so new that most users do not know how to incorporate standards and controls into their experiments. Furthermore, consistent production of target DNA has been problematic and a documented source of variability. My research centered on three questions: Can target DNA be cloned into plasmids and used for spotting on microarrays? Do plasmids work as well as PCR products? If you probe with known ratios, does the method detect those same ratios? The data indicate that plasmid DNA is indeed useable as a target in microarray experiments and is comparable to PCR product at producing a 1:1 Cy5:Cy3 dye ratio. However, DNA microarrays appear to under-represent the ratios of probes used under well-controlled conditions. These findings open the way for improved DNA microarray experimental design and quality assurance of results.

Role of milton in mitochondrial morphogenesis during Drosophila spermatogenesis.

M.M. Siegenthaler 1, R.S. Stowers 2, K.G. Hales 1. 1) Department of Biology, Davidson College, Davidson, NC; 2) Department of Molecular and Cellular Biology, UC Berkeley, Berkeley, CA.

The milton mutation was previously shown to be associated with defective mitochondrial transport in photoreceptor cells, and Milton appears to be an adaptor protein linking kinesin and mitochondria (Stowers et al., Neuron 36: 1063-1077). The milton gene is expressed during spermatogenesis, as shown by its high representation among testis EST sequences. During spermatogenesis, mitochondria undergo dramatic morphogenetic events, including aggregation and fusion in early spermatids and subsequent elongation beside the flagellar axoneme. To determine whether the milton gene product participates in these events, we made milton germline clones using the FLP-FRT mitotic recombination system. Contrary to our expectations, aggregation of mitochondria in early post-meiotic spermatids appeared normal in homozygous mutant cells. Instead, we observed aberrant elongation of mitochondria during the formation of the flagellar axonemes. We conclude that Milton is required for only a subset of the mitochondrial transport events during spermatogenesis. This work is supported by the National Science Foundation under Grant No. 0133335, as well as by Davidson College.

Golf course nestbox programs: are predator guards worth the expense?

Mark Stanback and Ned Conway

Many golf courses throughout the US are implementing nestbox programs as part of a new emphasis on environmental stewardship.  Although nestbox occupancy rates may be high, little is know about the demographic effects of these programs, especially considering that golf courses typically provide ideal habitat for a variety of nest predators.  Providing all nestboxes with predator guards (PGs) would presumably reduce nest failure rates, but without the knowledge of nest failure rates of unprotected and protected boxes, one cannot determine whether PGs are worth their expense.  We compared the nesting success of eastern bluebirds (Sialia sialis) in protected vs. unprotected nestboxes on seven golf courses near Davidson, NC.  On each course, half of the boxes were tree-mounted and half were pole-mounted with stovepipe PGs.  Overall, PGs had a dramatic effect on nesting success:  Half (130/257) of unprotected nests failed, while only 20% (29/142) of protected nests failed.  Excluding cases of nest abandonment without depredation, the effect of PGs was much stronger.  Only 5% of protected nests were actually depredated, while 45% of unprotected nests were depredated.  Snakes and mammals are the primary nest predators in the golf course environment, but are strongly deterred by PGs.

Do golf courses provide good breeding habitat for eastern bluebirds?

Mark Stanback, Ned Conway, Carrie Riley, Meg Seifert, and Ambrose Tuscano

Analysis of reproductive parameters of birds nesting on golf courses can provide valuable information on the biological effects of turf maintenance activities on wildlife.  Because eastern bluebirds (Sialia sialis) nesting on fairways feed their young on insects collected primarily on managed turf, they may be especially vulnerable to the chemicals used there.  For four seasons (1999-2002) we monitored 150 nestboxes in control habitat (hayfields and pastures) and 250 on golf courses near Davidson, NC for first egg date, clutch size, brood size, and nestling condition.  Non-golf habitats outperformed golf habitats for all measured variables, but significantly so only for first egg date and clutch size.  Nestlings raised on golf courses were in poorer condition than those raised in non-golf habitat, though this effect was not significant when only a single chick from each brood was used in the analysis. 

Optimizing comparative RT-PCR for undergraduate cell biology labs

Victoria A. Statler and Karen Bernd

Cognitive research shows that even with good instruction, the most academically talented students often understand less than some might think.  Because of this disjunction, many undergraduate science courses offer laboratory exercises – in addition to lectures.  Newer approaches to biology entail an investigative approach within the laboratory.  This project will allow undergraduate students to include differential gene expression analysis in their repertoire of technical methodology.  Through the development of reliable primers and a sensitive comparative RT-PCR protocol, students will be able to see how genes are expressed during yeast mating in their undergraduate lab courses.  Such an approach will ideally become a “course-friendly” and exportable protocol that will make studies in gene expression analysis more accessible.  The hands-on experience will make students more active learners and increase their understanding and retention of this kind of information.

Quantitative measurements of planaria locomotion and regeneration

Rebecca Thomason

Planaria are freshwater flatworms commonly known for having regenerative characteristics-when the organism is split in half, it has the ability to regenerate a new head or tail.  I observed the locomotive activity of planaria (Dugesia tigrina) before and after bisection and during regeneration.  Basing these observations on a qualitative scale, the tail pieces moved more slowly compared to the head pieces until the tails regenerated a new head.  These results encouraged a new, more quantitative measurement method of locomotion regeneration.  I designed a digital video microscopic method to measure the speed of locomotion of planaria.  I measured planaria locomotion in two dimensions on a microscope slide marked with a grid.  A digital video camera was positioned on a stereomicroscope to film planaria locomotion and calculate the speed.  The experiment was conducted over a period of several days [up to six days], enough time for a head to regenerate on the tail of the planaria.  Before a head regenerated on a tail piece, the planaria’s locomotion tended to be more slow and short in movement but increased as head structures regenerated.  The rate of locomotion of head pieces stayed generally consistent throughout the experiment.  Planaria head pieces displayed enhanced speed, longer strides, and more looping in comparison to the tail pieces. 

Characterizing golgin 160 c-terminal targeting and localization in Hela cells using immunofluorescent golgi markers.

Paul T. Toran

The Golgi apparatus is the organelle responsible for both intracellular and extracellular protein trafficking. Comprised of cis, medial, and trans membrane networks, the structure of the Golgi apparatus is maintained by a series of proteins.  One such family of proteins is the golgin protein family.  These proteins were identified in patients suffering from autoimmune diseases because their bodies created auto-antigens against golgin proteins.  Golgin 160 is a member of the golgin protein family and is believed to play a role in the maintenance of Golgi structure.  This paper investigates the localization of the c-terminal end of golgin 160, GCP170 aa 1376 - 1530.  The GCP170 1376 - 1530 construct was created with a GFP tag on the N terminal end of the construct to be used in transient transfections into immortal HeLa cells.  Known Golgi proteins, GM130, p115, and GBF1, were used as immunofluorescence markers.  The c-terminal end of golgin 160 was localized to the cis/medial Golgi and has very similar colocalization with GBF1.  It is possible that the c-terminal of golgin 160 may interact with GBF1 in the cis/medial Golgi.

The effect of a TrkB receptor inhibitor on Xenopus retinal ganglion cell dendritic arborization in vivo

Graham Watson and Barbara Lom

The morphology of a neuron’s dendritic arbor profoundly influences its ability to receive and transmit synaptic information.  Consequently, dendritic differentiation plays a critical role in determining a neuron’s role within the nervous system.  To understand how neurotrophic growth factors influence the differentiation of developing dendrites we have examined Xenopus retinal ganglion cells (RGCs) dendritic arborization in vivo.  Previous work from our lab demonstrated that RGCs are sensitive to brain derived neurotrophic factor (BDNF).  Target-derived BDNF promotes the arborization of developing RGC dendrites, while retinal-derived BDNF inhibits RGC dendritic arborization.  BDNF is known to signal via the transmembrane trkB receptor, but it is not known if trkB participates in dendritic arborization.  To determine if trkB signaling mediates dendritic arborization we have examined the consequences of the pharmacological trkB inhibitor K252a on the morphology of Xenopus RGC dendrites in vivo.

Nicotine reduces growth and movement but enhances pigmentation in Xenopus tadpoles

Drew Weber

Gaining a better understanding of how nicotine affects normal development is essential in informing expecting mothers about the risks and consequences of smoking during pregnancy. In these experiments the FETAX (Frog Embryo Teratogenesis Assay: Xenopus) was used to determine the teratogenicity of nicotine and the types of developmental abnormalities it causes in developing Xenopus laevis tadpoles. Xenopus is a useful model organism because of its rapid development and sensitivity to environmental changes. Previous studies indicate that nicotine is a teratogen, but nicotine’s influence on embryonic morphology was not fully examined (Dawson, 1988). Building on Dawson’s work, these experiments observed four abnormalities, confirming that nicotine is a teratogen in developing tadpoles. In two independent experiments, nicotine decreased tadpole length, motor function, and eye diameter, but increased pigmentation in a dose dependent manner. Because nicotine is an agonist to acetylcholine receptors (AChR) predominately in muscle and nervous tissue, these data demonstrate that increasing ligand concentrations for nicotine acetylcholine receptors (nAChR) disrupts normal development in Xenopus. The risk of sudden infant death syndrome (SIDS) has been shown to increase significantly with fetal nicotine levels (Haglund, 1990). The results of this FETAX assay demonstrate the negative consequences of exogenous nicotine on tadpole development and should be considered when informing expecting mothers about the risks of smoking.

Abstracts from the Department of Chemistry

A two step synthesis of 4-methyl-2,2’-bipyridine

Adam Dutko and David Blauch

Asymmetrically substituted bipyridine ligands and their metal complexes have found wide application in electro, photo and quantum chemistry.  However, most asymmetrically substituted bipyridines, specifically with groups in the 4’ and 5’ positions, have traditionally proven difficult to synthesize.  The primary purpose of this project was to refine a Kröncke-type two-step synthetic route based on the method of Treffert-Ziemelis and use it to synthesize 4-methyl-2,2’-bipyridine.  The proposed route to the 4-methyl-2,2’-bipyridine ligand involved the reaction of crotonaldehyde with 1-(2-pyridinylcarbonyl)pyridinium salt.  Analysis of the reaction mixture by GC-MS and NMR confirmed the 4-methyl-2,2’-bipyridine ligand had indeed formed, but purifying the compound by the suggested method proved difficult and provided low yields.  After monitoring the room temperature reaction mixture over a three-day period by proton NMR spectroscopy, the product was detected but the majority of the crotonaldehyde had been consumed by side reactions.  Modifications of the procedure to avoid these side reactions have been explored.

Trapping of iminium ions in horseradish peroxidase-catalyzed N-demethylation reactions

Annette Welty and Erland Stevens

The use of enzymes as catalysts for organic reactions has become a popular synthetic technique.  Enzymes are naturally occurring and are in many cases easily obtainable, as with horseradish peroxidase.  This particular enzyme subjects aniline derivatives to oxidative N-dealkylation reactions proceeding through the iminium intermediate.  This intermediate ion is usually short lived in the overall reaction.  The iminium intermediate may be trapped, however, by designing the substrate in such a way that the intermediate undergoes an intramolecular reaction.  An intramolecular Mannich reaction is used to trap the iminium ion formed from 1-(N-methylanilino)-3-butanone.  The result of this reaction, rather than the usual dealkylated product, is a cyclic structure.

Synthesis of 5-carboxyl-2,2’-bipyridine ligand

Beau Dasher and Durwin Striplin

The synthesis of the title compound began with the preparation of a precursor, 2-trimethylstannyl pyridine, which was obtained from  the reaction of n-butyllithium with trimethyltin chloride at -78oC in nitrogen atmosphere. The 2-trimethylstannyl pyridine was produced in high yields and characterized by Nuclear Magnetic Resonance (NMR) spectroscopy.  Ethyl 6-chloronicotinate was reacted with the 2-trimethylstannyl pyridine product to synthesize the crude ethyl ester bypyridine product which was also characterized by NMR and Thin Layer Chromatography (TLC) and then hydrolyzed with sodium hydroxide to form a sodium salt of 5-carboxyl-2,2’-bipyridine.  An aqueous extraction with water and hydrochloric acid was used to precipitate and purify the final 5-carboxyl-2,2’-bipyridine product.  The product was then characterized by NMR.

Phosphorescent complexes with cyclodextrins and bromonaphthalene derivatives used as optical biosensors

Benjamin F. Teresa and Merlyn D. Schuh

Carrier-based ion-selective electrode sensors (ISEs) have been used to detect ionic species in several applications; however, their disadvantages include the stringent requirement for compatibility between components and necessity for expensive electronics.  There are inherent advantages to developing phosphorescent complexes as bulk optical sensors: the long lifetime nature of phosphorescence enables sensitivities of several orders of magnitude, these sensors would be water soluble, and they should be less toxic.  The objectives include the investigation of host-guest complexes that incorporate cyclodextrin hosts with a bromonaphthalene derivative guest in the triplet-excited state.  Specifically, this guest-host complex is to be used for determination of the concentration of cationic species in aqueous solution.  The sensitivity of the complexes to quenching protection afforded by potassium and sodium ions as a function of concentration is studied.  In an attempt to enhance ion-specificity in quenching protection sulfated cyclodextrins and methylated cyclodextrins are used as host molecules; and several different bromonaphthalene derivative guest molecules are used.

Formation and Suzuki coupling of aryl pinacol esters for biaryl synthesis

Brian Borak and Erland Stevens

Biaryl compounds comprise a wide variety of important pharmaceuticals and natural products, including alkaloids and terpenes.  Various methods for their synthesis have been developed, however, the Suzuki coupling is preferred due to its straightforward procedure, relatively mild reaction conditions, benign waste products, and reasonably high yield.  Ester intermediates, formed from reaction of an aryl bromide with diboron, are reacted in situ with the same aryl bromide or a different aryl bromide to form the homo-coupled or hetero-coupled product, respectively.   This project was directed towards synthesizing new biaryl compounds through the Suzuki coupling using several synthesized aryl bromides.  These aryl bromides were reacted to form pinacol esters which are relatively stable (compared to other boronic esters) and subsequently allow for a more successful coupling reaction thereafter. 

The synthesis of modified di-2-pyridylmethanamine (dipa) ligands

Alfred Lloyd Bowie Jr. and David Blauch

Modified di-2-pyridylmethanamine (dipa) ligands can be made from the corresponding ketone and various methylamine-containing components.  The behavior of these derivatives when bound to ruthenium is an area of current research.  This study not only anticipates the validation of facile chemistry that can be employed for the production of such ligands but also attempts to provide techniques that are scalable.  The N-methyl derivative of this family was synthesized via a titanium isopropoxide intermediated that was subsequently attacked by methylamine.  The ethanamine derivative is being sought via a multi-step synthesis that converts the ketone into the alcohol with a methyl substituent on the central carbon.  The alcohol is then substituted for a tosylate species, which is attacked by azide, and this species is then reduced to the amine.  

Synthesis of methyl-substituted 8-aminoquinoline

Gregory E. Scott and David Blauch

Ruthenium complexes with 8-aminoquinoline ligands polymerize upon oxidation.  This synthesis was designed to produce methyl substituted 8-aminoquinoline ligands that could be used to create ruthenium complexes that would be too sterically hindered to polymerize.  The preparation of 2,4,5,7-tetramethylquinoline was accomplished from the reaction of 3,5-dimethylaniline with 2,4-pentanedione.  The quinoline was nitrated and reduced to produce the aminoquinoline.  The nitration yielded a mixture of 6- and 8-nitroquinolines.  To obtain nitration exclusively in the 8 position, one may begin with 3,4,5-trimethylaniline and 3-methyl-2,4-pentanedione to block the 6 position.

Determination of squalene in commercially available olive oils by high performance liquid chromatography.

Griffin R. Myers and David N. Blauch

The content of squalene in commercially available olive oils has been determined by high performance liquid chromatography.  Squalene, C30H50, is a long chain hydrocarbon that has been shown to perform significant antioxidant functions in vivo.  Squalene has been extracted from pure samples of commercially available olive oils via a solvent extraction at low temperature; the resulting samples have been prepared for quantitative analysis by filtration and dissolution.  High performance liquid chromatography and UV-Vis spectrometry has been used to quantify the content of squalene for each selected olive oil sample.

Characterization and modification of the bis-ene-hydrazine tautomer in the Piloty pyrrole synthesis

Matt Whited and Erland Stevens

Pyrroles are valuable chemicals with several important applications, most notably in the synthesis of porphyrins and semi-conducting organic polymers such as polypyrroles.  The Piloty pyrrole synthesis is seemingly a very attractive route to the synthesis of complex pyrroles from simple ketones and hydrazines, but to this point has been extremely limited in scope due to the paucity of successful applications.  Since the primary limitation on the Piloty synthesis is the instability of the bis-ene­-hydrazine tautomer that forms as a necessary intermediate, several experiments have been conducted to trap the unstable tautomer and overcome this barrier.  In one series of experiments, phthaloyl dichloride has been used to transform this tautomer into a stable intermediate.  In another series of experiments, the synthesis of N,N’-dibenzylhydrazine has been attempted in order to form a variation of the bis-ene­-hydrazine tautomer that should withstand harsher reaction conditions and form substituted pyrroles by the Piloty pathway in high yield.

Synthesis of a series of iso-structural metal-terpyridine complexes with different redox activities

Matt Whited, Tyson Chasse, and Christopher Gorman

Terpyridine molecules, which can act as metal chelates, were synthesized with thiol-terminated alkyl chains to facilitate self-assembly on gold surfaces.  These molecules can be used to make asymmetric bis(metal-terpy) complexes to serve as headgroups in self-assembled monolayers.  The synthesis began with the formation of 4'-(methylthio)-2,2':6',2''-terpyridinyl from 2-acetylpyridine, after which a methyl group was substituted for the methylthio group using methyl Grignard.  A halogen-terminated alkyl chain was added to the methyl group in an LDA reaction, and finally the thiol termination was installed via a thiourea intermediate to yield 4'-(5-mercaptopentyl)-2,2':6',2''-terpyridinyl.  Bis(metal-terpy) complexes are currently being synthesized from this molecule for self-assembly on gold surfaces.  These self-assembled monolayers can then serve as the basis of correlating redox potential with other nanoelectronic behaviors.

Developing a forensic chemistry laboratory experiment

Matt Young and Cindy Hauser

An instructional laboratory procedure was constructed where students will use analytical chemistry techniques to solve a crime.  Elements of forensic analysis and thought will play a major role in solving the crime, and this laboratory procedure will be implemented in Davidson College’s advanced laboratory course: Chemistry 361.  Various experiments were explored to determine if they were suitable for use with the available instrumentation.  Forensic analyses performed include: identification of pen inks, detection of amino acid residues in fingerprints, determination of blood alcohol content, and identification of gun shot residue.  High Performance Liquid Chromatography, Atomic Absorption Spectroscopy, Gas Chromatography, and Thin-Layer Chromatography were all used to analyze various pieces of forensic evidence. 

Determination of lycopene content in raw tomatoes and tomato products with an emphasis on culinary preparation

Michael Megison and David Blauch

The objective of this project is to determine how lycopene concentrations vary in raw tomatoes and tomato products with different methods of culinary preparation or cooking. Dry weight percentages of lycopene will be found for raw tomatoes and the various tomato products. Subsequently, the tomatoes will be prepared in several methods of culinary preparation, such as sautéing, stewing, and saucing. Once the tomatoes have been cooked, a dry weight percentage will be found as well. The dry weight percentages will be compared in order to find out whether or not culinary preparation increases the lycopene concentration in the dish being prepared. The purpose of this research is to determine whether some preparation techniques are more suitable for adding higher amounts of lycopene to a diet. Lycopene is important in everyone’s diet, as it is a strong antioxidant that has been proven to have cancer preventative effects in the body.

Mechanistic study of the activity of horseradish peroxidase in trifluoroethanol

Phillip Smith, Merlyn Schuh, and David Blauch

The activity of horseradish peroxidase, incubated in 5% trifluoroethanol, was studied.  Previous studies have shown that peroxidase shows increased activity in this organic solvent mixture due to changes at the active site of the enzyme.  In an effort to study this effect, methods were determined to monitor the oxidation of several phenolic substrates through detection of the fluorescent reaction products.  Initial velocities of reaction were determined by curve-fitting.  Michaelis-Menten constants and maximal reaction velocities were calculated assuming Michaelis-Menten reaction kinetics.  This analysis facilitated correlation of enzyme activity to substrate hydrophobicity (quantified using Hammet parameters).  Correlation analysis allowed insight into the nature of the enzyme active site in this organic solvent mixture.

Method development for analytical determination of pesticide levels in golf course water

W. Stephen Choate and Cindy D. Hauser

Consumer use of pesticides, such as the application of pesticides for golf course maintenance, raises questions about the contamination of waters, food, and other environmental matrices. Instrumental analysis can be used to identify areas of contamination and to determine potential health risks. A method for the preparation of water samples collected from two local golf courses has been developed using Supelco ENVI-8 solid phase extraction disks. The pesticide concentrations in the samples were analyzed using a Varian 3800 GC equipped with a Varian Saturn 2000 ion trap mass spectrometer. An organophosphorous pesticide standard mixture has been used to determine the linearity and the limits of detection for the method. The pesticide levels in the water samples were found to exist below the limits of detection.

Ruthenium reclamation from chemical waste

William Childs and David Blauch

The expense of ruthenium compounds has raised a need to recycle waste material containing ruthenium to further future projects.  The rarity and desirability of the metal makes ruthenium chemistry costly.  However, previous research has yielded large amounts of waste ruthenium.  This research aimed to isolate ruthenium from waste and convert it into a usable starting material for future experiments.  The metal was isolated by oxidization to ruthenium tetroxide, which is volatile (b.p. 40oC).  As the ruthenium tetroxide was produced, it was swept with a nitrogen stream into a hydrochloric acid solution which reduced the metal to ruthenium trichloride.  Recovery of ruthenium trichloride was completed upon evaporation of the acid solution.  The recovered material was found to contain substantial amounts of the original waste ruthenium through atomic absorption spectroscopy, and was a successful starting material for the preparation of Ru(DMSO)4Cl2 (DMSO = dimethylsulfoxide).

Environmental effects of common herbicides, pesticides, and fertilizers used on sports fields and possible green alternative solutions

Andrew Musashe

In this study, the typical maintenance of sports fields and golf courses was examined for its harmful effects on the environment including its possible threat to humans and other organisms.  Baseball, football, and soccer fields were the three different types of sports fields studied in conjunction with golf courses.  The main emphasis of this analysis was on golf courses.  Recently, environmental agencies have begun to attack golf course management and new course development for their detrimental effect to the environment.  A green solution is needed in order to alleviate the threats of these necessary processes.  Controlled-release fertilizers through polymeric membrane devices were studied for its possible green replacement of hazardous chemicals currently used.  This project was aimed to inform sports fields’ maintenance workers and athletes who play on these fields.

Environmentally-friendly methods for oxidation of alcohols

Ashley Crimmins

Roger Sheldon of the Delft University of Technology has been instrumental in developing a number methods for the oxidation of alcohols to aldehydes or carboxylic acids and ketones.  Current methods have environmentally-unfriendly and/or stoichiometric byproducts.  Sheldon’s efforts have sought to eliminate stoichiometric byproducts while maintaining conversion rate and selectivity.  One method developed involves a piperidinyl oxyl-catalyzed oxidation with sodium hypochlorite.  This method is effective for oxidizing alcohols in an environmentally benign solvent.  Further benefits of this process were that it was capable of aldehyde selectivity.  Although this process is a market improvement over previous processes, it generates stoichiometric sodium chloride as a byproduct which is not desirable.  Sheldon has also detailed two other processes, both of which give good conversion and selectivity but are typically incapable of converting alcohols that contain heteroatoms.

Naturally occurring defense mechanisms in plants

Benjamin Barnes

The use of synthetic pesticides is a source of many environmental concerns.  This project looks into some of the many methods plants use to protect themselves, specifically, chemical antifeedants, harpin proteins, pyrethrins, and other naturally occurring pesticides. Exploitation of these naturally occurring defenses offers a commercially viable and environmentally friendly option for commercial crops.  This research focuses on the practical utility, benefits, and mechanisms by which these chemicals protect the plant.

Enzymatic degradation of organophosphorous nerve agents

David Campbell

Since World War II governments have been stockpiling nerve agents as part of their chemical warfare arsenals.  Now it is estimated that over 200,000 tons exist worldwide.  The toxicity that has prompted the nerve agent’s use as a powerful weapon is also a liability to its handlers and an effective death sentence to the environments on which it is unleashed.  With the advent of the Chemical Weapons treaty calling for the demilitarization of these stockpiled nerve agents and with the mounting environmental awareness and demands, efficient and environmentally friendly processes are being developed to clean up and decontaminate these nerve agents.  Using organophosphorous hydrolyzing enzymes immobilized on a polyurethane foam matrix researchers have developed a stable, reusable catalyst that is capable of efficiently degrading these nerve agents.  It is projected that just 2.5 kg of the fixed enzyme should be able to degrade up to 30,000 tons of nerve agent in a year. 

The development and feasibility of fossil fuel biodesulfurization technology

Elizabeth Anne Gross

This project summarizes research conducted concerning the potential for the introduction of biodesulfurization technology into the oil refining industry.  The current desulfurization technique, hydrodesulfurization (HDS), will be insufficient to meet the sulfur limits required by new EPA standards, which require the reduction of sulfur in fossil fuels from 300 ppm to 30 ppm by 2004.  Sulfur in gasoline is hazardous because upon the combustion of fossil fuels, the sulfur is released into the atmosphere in the form of SO2, a gas that causes acid rain and can also lead to acute bronchitis and severe respiratory disorders when inhaled by humans.  Research has found that biodesulfurization (BDS) is one of the leading alternatives for a desulfurization technology that can be used to complement or replace HDS in oil refining.  Dibenzothiophene (DBT) is a compound contained in crude oil that is representative of the sulfur-containing compounds that are difficult to remove using HDS.  Several enzymes from the Rhodococcus strain have been found to remove sulfur from the DBT in fossil fuels, while allowing the carbon skeleton of the compound to remain intact, thus preserving fuel value.  The enzymes metabolize the sulfur-containing compound, releasing the sulfur as sulfate, which can be easily removed.  While HDS is run at high temperature and pressure (200-400 degrees Celsius and 150-250 psig), BDS can be run with ambient temperature and pressure.  BDS also produces no toxic by-products, and has the potential to be more energy- and cost-efficient than HDS.  Research is currently attempting to find a way to make BDS an economically feasible process for the oil refining industry. 

Glyphosate: an environmentally friendly herbicide

Erin Brockway

In 1995, the world used 1,002 million kilograms of herbicides, more than any other type of pesticide.  While herbicides are used to control weeds and increase crop production, they also represent a viable threat to the environment due to toxic effects in non-target organisms, overuse, and herbicide resistant weeds. Glyphosate (N-(phosphonomethyl) glycine), a broad-spectrum herbicide, poses a possible solution to the herbicide conflict.  Also known as Roundup, glyphosate effectively and non-selectively kills all plants by inhibiting the shikimic acid biochemical pathway.  Since the shikimic acid pathway is not present in non-target organisms, glyphosate is of relatively low toxicity.  In addition, the use of glyphosate in conjunction with genetically engineered glyphosate-resistant crops holds the potential to reduce soil loss due to tillage, decrease the use of more toxic herbicides, and slow the onslaught of herbicide resistant weeds. This research investigates the biochemical mechanism, toxicity, and agricultural applications of glyphosate, thus highlighting its superiority and promise as an ecologically friendly herbicide.

The use of enzymes and microorganisms in the synthesis of pharmaceuticals

James A. Simmons

Each year the pharmaceutical industry manufactures between 10-103 tons of product; however, 250 to 105 tons of waste is produced as well.  This results in a Sheldon E factor, a ratio of kilograms of waste to kilograms of product and used to determine the environmental friendliness of a chemical process, between 25 and 100, which is extremely high.  Environmentally friendly processes have a Sheldon E factor ranging from 0 to 1.  Also, many chiral drugs have only one active enantiomer, either the (R) or the (S) conformation.  Because of the negative effects of Thalidomide use, chirality is a huge concern in new drug discovery, and the FDA will continue to place harsh restrictions on new chiral drug approval.  Biocatalysis, the use of enzymes or microorganisms in the synthesis of organic compounds, is an attractive solution to the problems of massive waste and necessity for chiral drugs.  Their substrate specificity, stereospecificity, regiospecificity, low energy consumption, lack of waste, lack of toxicity, and reduction of steps in synthesis make enzymes or microorganisms an appealing method to the pharmaceutical industry.  However, the use of enzymes or microorganisms has its limitations, which include low product yield, slow reaction time, extreme sensitivity, and expensive costs in finding a specific enzyme or microorganism to suit the needs of the reaction.  Presented in this poster is a survey of the use of enzymes or microorganisms in the production of pharmaceuticals. 

Enzymatic degradation of plastics and polymers

Jenny Bruggers

The accumulation of plastics in the environment has become a cause for concern, as they have a very slow natural degradation time and account for approximately twenty percent of the total volume of landfills.  This problem will continue to increase proportionately as dependence on polymer materials for making these plastics increases, since only a quarter of the polymers used are currently being recycled.  Chemical methods, like hydrolysis and oxidation, have been known for a while and are useful for degrading some polymers.  While these methods are practical in the laboratory, they are much less useful in environmental situations.  On the other hand, bacteria are found naturally throughout the environment and have been observed to grow on and degrade polymers.  To this end, the isolation and genetic manipulation of some bacteria has been pursued for the specific degradation of various polymer substrates.  However, these methods have yet to be tested extensively in actual landfill sites and are mostly restricted to laboratory tests.  If the bacterial enzymes that have been discovered thus far can be genetically engineered to increase the breakdown of polymers while using them as the sole carbon source for metabolic function, they may be a viable solution for the vast landfill space currently being used.  Even so, there are still some polymers, like polystyrene, that are almost completely resistant to degradation by either enzymatic or chemical means.

Spinosad and other green pesticides for use in farming and the improvements over current non-green pesticides.

Joshua Layfield

Every year, of the 2.1 billion kilograms of active ingredients used in pesticides worldwide, 568 million of those are found in the United States alone.  These active ingredients usually only constitute 5-10% of the total volume of the pesticides actually applied.  Many of these pesticides are non-specific to the target organisms and can cause unforeseen problems down the line from the original application to the plants.  Dow Agrochemicals has created spinosad the active ingredient of the Tracer pesticide.  Spinosad has shown promise in its high specificity for target organisms and low toxicity for non-target animals.  Spinosad has also shown low persistence in the environment and no toxicity of its metabolites.  I will be comparing the effects of these new pesticides on the target pests and also the environment with the effects of the older less green pesticides.

The conversion of biosolids and paper mill sludge into activated carbon catalysts and sorbents

Leslie Cook

As the human population increases, biosolids – a byproduct of wastewater treatment facilities – are becoming an increasingly large environmental problem.  Sludge produced as a byproduct of paper milling is a similar environmental dilemma.  Both biosolids and paper mill sludge can be converted into activated carbons that can be used as catalysts or sorbents.  The conversion of biosolids and sludge to activated carbon is a multistep process that involves drying the biosolids and sludge and then exposing the material to light and humidity to increase the pourousness and surface area of the product.  A catalyst made by activating the carbon in paper mill sludge has been able to reduce NOx compounds to N2 in the presence of carbon monoxide.  This research is important to green chemistry because it is using a feedstock that would otherwise be waste.  Also, the conversion of the biosolids and sludge to the activated carbon is environmentally friendly, and the potential catalytic and sorbent use of products can help promote a clean environment. 

Yttrium as a lead substitute in cationic electrodeposition coatings

Matt Armstrong

This project explores PPG Industries’ discovery of Enviro-Prime 2000 lead-free anti-corrosion electrodeposition coatings for automobiles.  This breakthrough introduces yttrium as a replacement for lead without sacrificing corrosion inhibition.  The coating composition comprises an active hydrogen-group containing electrodepositable resin and a curing agent with functional groups reactive with the hydrogen groups. More plentiful in the earth’s crust than lead, yttrium is 100 times safer at typical levels of use.  The official international patent granted to PPG Industries was researched in addition to a summary of the company’s 2001 Presidential Green Chemistry Award for Designing Safer Chemicals.  As use of toxic heavy metals is circumvented, the process’ emissions of volatile organic compounds are significantly reduced, low-nickel pretreatments and chrome-free rinses are used, and decreased curing temperatures save energy and costs.

Ionic liquids as green alternatives in organic chemistry

Michael Jenks

Over the past decade, the demand for “greener” chemical processes has led to extensive research in the area of room temperature ionic liquids as media for chemical reactions.  This poster examines the potential applications of ionic liquids.  The properties of ionic liquids, “classic” organic reactions in ionic liquids, and catalysis involving ionic liquids are discussed.  The future of ionic liquids is also discussed.

Thermolysin and subtilisin cross-linked crystals in biocatalysis

Nicholas Mantini

The superiority of cross-linked enzyme crystals above crude enzyme catalysts and immobilized enzymes was studied in this investigation.  Special attention was paid to the hydrolysis mechanism of Thermolysin and Subtilisin.  Knowledge about the hydrolytic action of the metallo-protease, Thermolysin, and serine protease, Subtilisin, was then utilized to run reactions in reverse (i.e. synthesis of peptides, the optical resolution of alcohols, and trans-esterification of alcohols).  Although CLECs (cross-linked crystal enzymes) demonstrate similar catalytic activity as crude or immobolized enzymes, their three-dimensional configuration allows them to match enantiomeric specificity with durability.  In particular, CLECs can exploit the benefits of organic solvents and they have the ability to function at temperatures and pH levels that denature crude enzymes.          

A green, biodegradable alternative: Donlar's thermal polyaspartate polymers

Sara Holmberg

Polyacrylate (PAC) is a widely used synthetic anionic polymer with many applications: its chief uses are as a scale inhibitor (preventing buildup of insoluble materials in places like pipes and pumps), a dispersing agent in products such as detergent (giving particles a negative charge so that they repel each other), and as a superabsorber when cross-linked (used in products such as diapers).  Although PAC is effective, nontoxic, and environmentally benign, it is not biodegradable and persists in wastewater and landfills.  Donlar Corporation has devised a method for commercially producing thermal polyaspartate (TPA), a biodegradable polymer with nearly identical applications to PAC.  Donlar received the Presidential Green Chemistry Challenge Award in 1996 for their work in developing this process, which uses aspartic acid as the starting material and creates no harmful byproducts.  This investigation describes Donlar’s method as well as the chemistry behind the biodegradability and commercial applications of TPA.

Abstracts from the Department of Mathematics

Assignment problems

Alex Sibley

Assignment problems concern the organization of individuals or objects into groups or categories, in accordance to given pairing restrictions.  Such a model covers a wide range of real world and theoretical topics.  Everything from drug and chemical interactions, to scheduling, to graph coloring can be modeled as an assignment problem.  This project investigates various assignment algorithms, including branch-and-bound and random assignments, as well as my own "greedy," "meta-greedy," and "polite" algorithms.

Traffic congestion minimization: Finding an optimal mix of Speed-Pass and change-collecting lanes along the Illinois Toll-way

Gregg Wallace

Toll systems are present in major cities around the world to control traffic flow and provide local government’s revenue necessary to maintain the transportation infrastructure in heavily traveled areas.  Urban planners must struggle with political and economic factors such as unions and rapid population as they seek to modify existing toll systems to adapt to new technologies, such as an electronic toll-collecting system.  In the case of Chicago, the electronic toll collection system known as “I-Pass” has reduced traffic congestion and grown immensely popular as it has provided commuters with the convenience of quicker toll collection.  In 2000, the Chicago Toll Authority (CTA) submitted a thorough report to the governor reporting the findings of their investigation of various options for the Chicago toll system.  I am creating a mathematical model to simulate the transportation and costs associated with travel on the Chicago toll-way.  I will focus on the scenarios that involve little to no change in physical toll structures.  I will seek to measure the effects of how a new scenario could adapt according to system pressures, such as inclement weather and traffic due to accidents, verses current models.  Overall, I will seek to identify a scenario that optimizes positive traffic flow and therefore minimizes congestion.

A mathematical model of bacterial growth rates

Joshua Layfield

Bacteria growth rates crucial to many of the biological processes that are essential to human life, especially in the digestive and excretory systems.  Ecologically nitrogen-fixing bacteria are incredibly important in providing nutrients for plant growth and protein synthesis.   Bacterial growth rates are affected by many factors and I will attempt to model the effect of these different factors on the rate of growth.  By maximizing or controlling the rate at which certain bacteria divide we should be able to help to prevent disease or create more effective production methods of producing antibiotics.   Measuring rates of bacterial growth is an extremely important technique that will only become more necessary in the future.  A group studying the genomic effects of mutation of a single gene has developed a method of sampling a large number of different species and determining the percentage of each species present by using fluorescent dyes.  This method is based upon the assumption that all of the strains of bacteria are mixed uniformly throughout a flask and that the sample size taken out each time is large enough to ensure that a representative mix of the flask is taken in each trial.  I am going to take a look at the validity of their findings in the light of the small sample size and possible heterogeneity of the mixtures that they used to sample data.  I will simulate the error propagation throughout the experiment and see how closely the reported values may differ from the actual rates of growth. 

Modeling Yellow Fever: Applications in epidemiology

Katherine Winter

Recent outbreaks of Severe Acute Respiratory Syndrome, West Nile Virus, foot-and-mouth disease, and the Hendra Virus continue to remind us that, ultimately, mankind is at the mercy of its environment. Disease outbreaks have and continue to affect the course of human history in extraordinary ways. Consequently, the rising field of epidemiology examines the origin, distribution, and control of disease within a population. Mathematical models are critical in the study of disease, as they allow epidemiologists to predict the spread of disease in populations through mathematical simulations. Given my interests in epidemiology and applied mathematics, I simulated the spread of yellow fever through a sample population using Mathematica. Yellow fever, a disease endemic to regions of Africa and South America, is spread via vector mosquitoes that carry the virus from one human host to another. The Mathematica simulation is generalized to predict the spread of any vector-born disease in a given population. In the end, the simulation will provide epidemiologists with the ability to measure the effectiveness of a variety of prevention strategies such as mosquito control and vaccination campaigns.

Cultural evolution: Modeling the extinction of family names

Parul Karnik

Family names survive through the line of male heirs. In the case that a family fails to produce a sufficiently large number of males, the surname can become extinct. Given the distribution of a surname within a population, we can produce mathematical models to determine the expected number of generations until extinction. The traditional approach, first proposed by Galton and Watson in 1874, uses generating functions to produce a solution. However, this is a simplified model that neglects immigration, overlapping generations, fertility rates, mortality rates etc. In my program, I use statistical analysis to produce more realistic probabilities. I then use a simulation developed in the Java programming language to solve the problem. Furthermore, I compare my solution with the one obtained by the traditional methods.

Abstracts from the Department of Physics

Using Java 3D to visualize calculations in advanced quantum mechanics

Adam Abele

We have developed new Java 3D programs (applications and applets) to help visualize the quantum mechanics in one, two, and three dimensions.  The programs we have created are part of the Open Source Physics (OSP) project’s growing set of physics simulations.  We have solved a variety of problems and imported their solutions into our visualization programs.  These problems include: one-dimensional potentials, a particle on a ring, two-d infinite square well (looking at the time evolution of simple superpositions), a particle on a disk, and a particle on a sphere.  Many of these visualizations will appear in the book Physlet Quantum Mechanics.  Additional information about the Open Source Physics project can be found at http://www.opensourcephysics.org/.

Random walk processes in astrophysics

Andrew R. Schoewe

Everyone knows that photons in a vacuum travel at the speed of light.  It may however be surprising to learn that when light is emitted from a star like our sun, it can take 30,000 years before any of that light actually escapes the surface of the star and radiates through space.  By applying the random walk model commonly found in statistical and thermal physics, I will theoretically model the emission of light from stars in one- and two-dimensional systems.  This phenomenon will also be numerically modeled using a Java applet.  Both the theoretical predictions and the numerical results will also be compared.

Gravity and tidal effects in the universe

Grady Patterson

Gravity is a fundamental force that causes all matter to interact with all other matter.  The Earth orbits around the Sun and your pencil remains on your desk because of it.  When two objects come close to one another, the force of gravity experienced by one side of an object is greater than the force experienced by the other side, creating a differential force.  One consequence of a differential gravitational force is the changing of the tides twice a day.  Differential forces caused by gravity are also responsible for the formation of rings, by sheparding moons, and the destruction of satellites inside a planet’s Roche limit.  When matter approaches a black hole it also experiences a differential gravitational force from one side to the other.  Using general relativity, we can explore what would happen to an object shortly before it crosses the event horizon.  The underlying principles behind these phenomena were explored as well as their relation to each other.

Analysis of diode laser coherence length using the Michelson interferometer

Michael Malenbaum

The Michelson interferometer produces interferograms, which can be converted into frequency spectra using a Fourier transform.  At low driving currents where spontaneous emission dominates, the width of the interferogram increases and the width of the spectrum narrows as the current increases.  The interferogram continues to expand as the current increases beyond the laser’s threshold current and the laser evolves from multi to single mode operation.  While the mechanics of the current experimental setup are inadequate for resolution of longitudinal modes, theoretical frequency spectra have been generated with and without these modes.  These spectra are then converted into theoretical interferograms.  If there are fundamental differences in the interferograms, the work should provide a basis for future experimental study.  Finally, we modulate the current of the laser to observe how the amplitude of phase noise in the interferometer output depends on the optical path difference within the interferometer.

Mode structure, cutoff, and polarization in optical fibers

Nick Hansell

When light is coupled into a fiber-optic cable, different modes will propagate depending on the initial conditions of the coupling.  Changing the wavelength of the incident light can eliminate modes and cause the dominant mode to change.  We have observed several distinct modes and explored how the intensity of transmitted light changes as the wavelength is tuned through a mode cutoff.  Light that propagates through single mode polarization-preserving fiber-optic cables is a combination of two independent components having electric field oscillations along the fast and slow axes of the fiber.  These two axes are perpendicular to each other and the axis of propagation.  Since the fiber is birefringent, the propagation constants along these two axes differ.  Coupling light into the fiber with a linear component along each of the two optical axes causes the polarization of the light to vary periodically along the length of the fiber.  The length of this periodic “beat” can be measured and used to calculate the other important characteristics of the fiber.

Excitation intensity dependence of sub-bandgap photoluminescence in InGaAs/InAsP heterostructures

Peter Campbell, Tim Gfroerer, and Mark Wanlass (NREL)

Low bandgap InGaAs/InAsP heterostructures grown on InP substrates are promising candidates for thermophotovoltaic cells, devices that convert thermal radiation into electricity.  Increasing the Indium concentration in the InGaAs decreases the energy threshold of the converter, but also increases the degree of lattice mismatch relative to the substrate.  Lattice mismatch introduces defect states within the bandgap, which usually decrease the conversion efficiency by making a path for rapid nonradiative recombination.  Preliminary work indicates that increasing lattice mismatch in this system can lead to a redistribution of defect levels from mid-gap toward the band edges where they are less likely to facilitate nonradiative recombination.  We have identified a radiative mid-bandgap defect level that only appears for the near lattice-matched condition.  We measure the excitation-dependent photoluminescence intensity of this peak to explore the mechanism of electron-hole recombination through this level. 

General relativity simulations using Open Source Physics

Sharon E. Meidt and Wolfgang Christian

We report the development of simulations in general relativity that allow the user to explore space-time curvature and the role of the observer.  Our Metric Explorer app provides a series of tools that aid the user in visualizing the Schwarzschild metric.  We will introduce these tools and show examples of gravitational red shift, as well as the trajectories of particles and the trajectories of light in the vicinity of non-spinning black holes.  These simulations are based, in part, on material in Edwin F. Taylor’s recent book, Exploring Black Holes: Introduction to General Relativity.

Programs will be available on the Open Source Physics website, http://www.opensourcephysics.org/.

This work is generously supported by the National Science Foundation (DUE-0126439).

Approximation techniques for quantum mechanical processes in astrophysics

Sharon E. Meidt

Quantum mechanics is considered a scientific triumph of the twentieth century, yet there are relatively few exactly-solvable systems presently known.   This work focuses on standard approximation methods in quantum mechanics used to solve problems relevant to astrophysical phenomena.  Examples of such techniques include the variational approximation and perturbation theory.  The ground state and energy spectrum of the Helium atom, for instance, is solved for using the variational approximation. With time-independent perturbation theory, the fine and hyperfine structure of the Hydrogen atom is established.  Finally, time-dependent perturbation theory, along with Fermi’s Golden Rule and Einstein’s A and B coefficients, is used to determine transition rates from excited states via stimulated emission. 

A user friendly model of the principle of least action

Kevin Bell

            The Principle of Least Action is a fundamental physical principle that has implications in all realms of physics.  It is often given as a qualitative, conceptual explanation of a phenomenon, which helps provide physical intuition but lacks rigor.  Otherwise, it is found as a rule applied to an integral that yields little understanding to students.  The goal of this program is to build a user-friendly model of the Principle of Least Action with the OSP library’s tools.  The current program allows the user to change the path of a virtual particle and observe the corresponding change in action.  The next goal is to use a function parser to allow the user to input any recognizable function or composition of functions as a potential.  The final step is to build a method that iterates along an initial path and “relaxes” into the path of least action.  The idea is that we can allow physics students to gain some intuition for the physics and geometry of the system while keeping the math and rigor present. 

Visualizing the hydrogenic orbitals

Casey Chiang

            One of the classic problems in quantum mechanics is the solution of the wave equation for the Hydrogen atom.  Using separation of variables, we find that the wave equation is the product of the radial and angular equation.  This paper presents visualization tools for the Hydrogen atom consisting of three applets: graphs of the radial equation, the angular equation, and the wave function.  Each program lets the user select the appropriate quantum numbers before graphing the wave function  or its probability density.  There are also options that combine states, thus creating hybrid orbitals. 

Racing strategies in the cycling phase of triathlons

Mary Fulton

An elite athlete can sustain a constant power output for long periods of time (~1hr). Using the frontal cross sectional area of an elite racer, and the assumption that the athlete will maintain the minimum needed power to sustain maximum speed (i.e. power output will drop when drafting to ensure that speed remains constant and that he does not overtake the other cyclist and lose the advantage gained by drafting) we can model his velocity over time, and generate strategies for race situations based on physiological parameters.

Swing set physics: exploring the effects of coupled oscillators

Colleen Gillespie

The coupled oscillators in this study consist of two or more pendulums connected by a weak spring.  In this type of coupled oscillator, when one pendulum is set in motion, its energy will gradually be transferred to the second pendulum until all of the initial energy is found in the second pendulum and the first pendulum is completely still.  With only two pendulums, the energy will then be transferred back to the first pendulum, but with multiple pendulums, the energy transfers both to the next pendulum and the previous pendulum.  This paper examines the resulting wave motion as more pendulums are added.

The threshold of the spread of disease versus population density

Louise Kiefer

Diseases, depending on their individual characteristics, spread through populations at different rates and eventually either infect the majority of people or disappear naturally. I have written a program that examines the consequences of different kinds of diseases and their effects on a given isolated population. For example, varying incubation periods and level of contagion will change how much time it takes for the disease to reach its final stage. In addition, the total population as well as the population's ability to move will be modified in order to analyze the possible outcomes of an infectious disease. The main goal is to determine at which points a disease spreads to the entire population and at which points it dissipates without external influences.  The more densely population the area, the more quickly and abundantly the disease will spread due to the increased chances of more individuals coming in contact with the disease.

Java pool & molecular dynamics

Blair Reynolds

This paper presents a billiards/pool game in Java and compares the result to molecular dynamics simulations of the ideal gas law.  It is played much like a real game of pool using a mouse to rotate a pool stick around the cue ball.  The impulse delivered to the ball is control by the length of time the mouse button is pressed.  The simulation takes into account the force of friction between the table and the pool balls and the elasticity of the collisions.  The game will end when all of the different colored pool balls are hit into any of the six holes along the edge of the table.

Visualizing vector transformations and projections

Kiril Simov

Many physics and mathematics fields, such as classical mechanics, relativity, and quantum mechanics, require a change of the coordinate systems to account for various phenomena.  This change can be calculated using a matrix transformation.  The program provides a visualization of how a 2D vector is changed after being transformed by a 2x2 matrix.  The user can see the original vector, the grid of the original matrix, the grid of the transformed matrix, and the transformed vector.  Two modes of transformation are available: varying original vector and varying transformed vector.  In that way, the user can interact with the vectors see how a transformation in a given coordinate system is reflected in another system.  The program will be a useful tool for visualizing abstract concepts from linear algebra like eigenvalues and eigenvectors, thus making the learning process faster and easier.

Population relationships within a two-species ecosystem

Gavin Taylor

The populations of species within an ecosystem vary widely as various factors change.  For example, a high birth rate will increase the ability of the species to overcome severe stresses, while a lower birth rate may cause the species to go extinct.  The interdependence between species also is a major reason for changes in population; for example, a decrease in prey species will be closely followed by a decrease in predator species, due to the decreased food supply.  These dependencies can be studied using a two-species ecosystem, in which a predator species and a prey species interact and their populations charted over time.  Factors such as birth rate, initial populations, and maximum age also have an effect and can be modeled.  Preliminary work suggests that even a small change in variables can have an extreme effect in the populations, and that the shape of the predator population shadows the shape of the prey population.  The investigation treats each of these variables as an independent variable.  It is clear how each of these variables should be expected to affect the outcome; however, what remains to be studied is how large of an effect a small change has.

The physics of a rainbow

Martin Zahra

The program solves and displays the path of a ray of light traveling from air into a glass sphere.  The program follows the ray as it reflects and refracts several times at the glass-air interface—bouncing around inside the glass.  If the user selects to have white light incident on the glass, the light will contain rays of several wavelengths.  This difference in wavelengths will cause the rays to have a different index of refraction for the glass.  Because of this difference, the rays will bend at different angles as they refract.  After several iterations of reflections and refractions, the rays will form sundogs and a rainbow.  As the user drags the light source, he will be able to observe the changing angles between the rays of the rainbow.  The program provides an accurate model of reflection, refraction, and the optical effects that they generate.

Abstracts from the Department of Psychology

Retrieval of color information activates color perception areas

Sharon L. Thompson-Schill1, Robyn T. Oliver1, David H. Brainard1, Susan G. Robison2

1University of Pennsylvania, 2Davidson College

Many neuroimaging studies have reported that semantic retrieval of sensorimotor information is associated with activity near sensorimotor brain regions.  Although the proximity to sensorimotor regions has been interpreted as support for modality-specific models of semantic memory (e.g. Allport, 1985), these models predict that retrieval of semantic information should activate sensorimotor regions themselves rather than areas near them.  We hypothesized that previous studies might have failed to find activity in sensorimotor regions because subjects accessed a propositional representation of the semantic information (e.g. “apples are red”) rather than perceptual knowledge per se (e.g. the shade of red).  To test this idea we designed two color retrieval tasks that differed in terms of their potential for being completed using a verbal association strategy.  During fMRI scanning, subjects viewed triads of black and white line drawings of familiar objects, and indicated which of the two test objects was more similar to the third in terms of its real-world color.  In one task, the discriminations were between objects that differed categorically (e.g. tomato, cherry, sunflower) while in the other task the object colors shared a common category (e.g. tomato, raspberry, lobster).  Putative color perception brain regions were identified in individual subjects by comparing activity to color checkerboards and luminance-matched grayscale checkerboards.  Across subjects, within color category discriminations produced significant activity within the independently defined color perception areas, while the between color category discriminations did not.  Thus, under some conditions, semantic retrieval of color information can elicit activity in color perception regions.    

Rodent performance on a delayed non-matching to sample task is impaired by bilateral entorhinal cortex lesion

Ian Willoughby

Alzheimer’s disease is a neurodegenerative disorder whose early stages are marked by the degeneration of areas within the hippocampal formation, including the entorhinal cortex and the hippocampus proper.  This degeneration is accompanied by impairment on tasks involving short-term memory and attention, specifically spatially oriented tasks.   Studies have shown a correlation between lesions of the entorhinal area and impairment on such tasks.  Male Sprague-Dawley rats were trained to criterion on a delayed non-matching to sample operant task.  Each animal was given a bilateral lesion of the entorhinal cortex after reaching criterion.  After a six-eight day recovery period, animals were assessed at delay periods of 1 sec, 5 sec and 15 sec for 14 consecutive days post-surgery.  Animals demonstrated a deficit at all delay periods immediately after surgery, as well as a 3-8 day period of rapid recovery from this deficit, but did not return to pre-operative levels of performance.

Effects of environmental enrichment on sensitivity to the antinociceptive, diuretic, and aversive properties of kappa opioids

Paul Bryant

Group-housed rats have been found to be more sensitive than isolated rats to the antinociceptive effects of m-opioids.  Given findings that the k-opioid receptor system is similar to the m-opioid receptor system in that it undergoes significant post-weaning functional development, it is possible that rats housed under differential housing conditions may also exhibit differences in sensitivity to the behavioral effects of k-opioids.  The present study examined these differences by obtaining 16 male rats at weaning and housing them in either enriched or isolated environments for a period of 6 weeks.  Using the warm-water, tail withdrawal procedure, the antinociceptive effects of spiradoline, U69,593, and nalorphine were examined in both groups.  The effects of spiradoline on diuresis, along with its ability to establish a conditioned place preference were also examined.  Rats housed under enriched conditions exhibited increased sensitivity to the antinociceptive effects of all three drugs.  They also showed increased sensitivity to the diuretic and aversive properties of spiradoline.  Following these tests, the housing conditions were reversed such that rats initially housed under enriched conditions were then isolated, and those initially isolated were then exposed to an enriched environment.  After 50 days under these new conditions, the two groups did not differ in their sensitivity to the antinociceptive effects of spiradoline.  These data show that enriched rats are more sensitive than isolated rats to the antinociceptive, diuretic, and aversive properties of k-opioids, suggesting that environmental enrichment enhances the sensitivity of the k-opioid system during development.

Age-related differences in within-subjects irregular preferences

C. Blake Bergeron, Alissa Greenberg, Claire Hess, Katrina Papadopoulos,
Kea Sherwood, Kristi S. Multhaup, Mark E. Faust, and Steve Sanow

An irregular preference occurs when a person chooses A from {A, B, and C} and B from {A and B}. For example, if a person is given the choice of vanilla, chocolate, or strawberry ice cream and she picks vanilla, and then is given the option of only vanilla or chocolate and she picks chocolate, this is an irregular preference.  Previous research has documented that younger adults make irregular preferences, whereas older adults typically do not.  That research, however, utilized a between-subjects design where each participant was assigned to either the AB condition, or the ABC condition, so it is possible that groups of individuals could demonstrate the irregular preference whereas individuals do not.  The current research utilized a within-subjects design, having each participant choose from both the AB and the ABC choice groups.  Even when given both choice groups on the same sheet of paper, younger adults still demonstrated an irregular preference, whereas older adults did not.  Experiment 2 explored whether the Experiment 1 findings resulted from a unique combination of choice items or whether younger adults show irregular preferences with a variety of relationships between the A, B, and C choices. Younger adults displayed irregular preferences in all conditions. 

Are endings the end-all in quality of life ratings?

Alissa Greenberg, Katrina Papadopoulos, Blake Bergeron, Claire Hess, Kea Sherwood, & Kristi S. Multhaup

The present study investigates the importance of the ending of a person’s life when judging the overall desirability and happiness of that life.  Both young and older adults read two stories (one neutral and one experimental) about a character who lived for 80 years.  The neutral story described a character’s life in which nothing especially bad or especially good happened.  The experimental stories consisted of 75 years (Positive or Negative) followed by 5 years (positive or negative).  All participants rated both stories on desirability and happiness scales.  Although quality of life has different meanings for different people, all groups rated the neutral life similarly so the baselines were equated across age groups and conditions.  By contrast, there were interesting condition differences in the experimental stories that suggest life endings are very important in judging the overall quality of a life.  The participants weighted the last 5 years of a life 3.96 times more then they would if they weighted the first 75 years and last 5 years of a life equally.  However, because the Positive-negative life was rated higher than the Negative-positive life, the participants did not exclusively use the endings when rating the lives.  The present study supports the previous finding that young adults are influenced by end-effects in quality of life ratings, extends this pattern to older adults and, interestingly, shows no difference in the ratings of older and younger adults. 

How generation affects source memory

Kindiya D. Geghman, Kristi S. Multhaup and Audrey N. Swift

Generation effects (better memory for self-produced items than for provided items) typically occur in item memory; the present research explored generation effects in source memory.  In Experiment 1 undergraduates answered questions and read statements made by a face on a computer screen, where the key word was either scrambled or needed letters filled in.  Generation effects were found for both item recall and source recognition (which person did which task).  Experiment 2 replicated and extended the findings to conditions in which the external sources were two different people who were either shown in consistent locations or not.  The data suggest that the generation effect may extend to source memory and that item and source memory may have similar underlying mechanisms.

Exploring Proust: Are olfactory memory cues better than other context cues?

Meghan Singletary and Kristi Multhaup

This experiment examined the intrinsic value of olfactory cues.  In phase 1, undergraduates recorded autobiographical memories for 90 s in response to 8 cue words (coffee, lemon, onion, chocolate, soap, baby powder, Vick’s vapo rub, and suntan lotion).  In phase 2, participants repeated the procedure from phase 1 except the experimenter presented the participant with a corresponding single picture, multiple pictures, or odor for half of the cue words.  Participants recorded more autobiographical memories in the second phase in the cued condition than in the control condition.  Participants in the odor condition did not recall significantly more memories than participants in either picture condition, suggesting that the intrinsic value of olfactory cues is not superior to picture cues.

Effects of advertising on the prescription of anti-anxiety medications

Lauren Daniel and Cole Barton

The effects of Barnum statements in advertisements were analyzed by evaluating participant self-reported stress and coping response in hypothetical future stressful situations.  The parallel forms questionnaires contained either active or passive stress coping for participants to respond.  Participants taking the active survey replied with a significantly higher amount of active responses as compared to those taking the passive coping surveys.  Active coping surveys and active responses to Barnum statements were associated with lower stress levels than passive surveys.  Students taking the active surveys were also primed for the future stress response of working out to relieve stress.  These findings support the hypothesis that Barnum statements manipulate perception of stress, convincing consumers of possible disorders, and then to manipulating medicating behavior.

Case study: the impact of union activities on labor relations of Kerala, India

Nidhi Paul

This study looks at how well the trade unions provide for their laborers, the working conditions of the laborers and labor – management relations in Kerala, India. Kerala is home to the most traditionally adversarial trade unions in India. These trade unions are widely believed to have all but destroyed the economy of the state with their constant strikes and lockouts. The trade unions in Kerala has gained notoriety all over the world, and investors are very wary to invest there. 30 interviews were conducted with workers, managers, entrepreneurs, bureaucrats and academicians. The interviews yielded a variety of opinions, with the owners/management and the unions being largely hostile towards each other while the workers believed that belonging to a union was more beneficial than not. An analysis across job type was also conducted, with some large differences in opinion.


We thank the Departments of Biology, Chemistry, Physics, and Psychology for jointly funding this event.


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