2009 AAAS Student Poster Competition Winners

Congratulations to the 2009 AAAS Student Poster Competition Winners

AAAS recognizes the winners of the 2009 Student Poster Competition that took place at the AAAS Annual Meeting in Chicago. Their work in a variety of fields displayed originality and understanding that set them apart from their colleagues. First-place winners receive cash prizes thanks to the generous support of Subaru of America, Inc.

Brain and Behavior

Winner (tie): Diane Livio, University of California, Irvine
The Strength of Sexual Imprinting Effects in Zebra Finch (Taeniopygia guttata) Populations

Sexual imprinting during development affects the mate choice preferences of adults in avian species, and this process has been proposed to play a role in reproductive isolation mechanisms. My studies examine if these imprinted preferences maintain when populations evolve to have different frequencies of a novel phenotype. I tested the effect of phenotype frequency on the strength of imprinted preferences; in doing so, I also tested the effect of non-parental conspecifics on imprinting strength, as well as the imprinting effects in males and females. I tested mate choice preferences of male and female zebra finches (Taeniopygia guttata) reared by parents either with or without artificial crests, in two populations with different frequencies (1/3 and 2/3) of crests present. I hypothesized that the more the offspring are exposed to the crest mutation, the stronger the imprinting effects will show in terms of relative preference for the crest in mate choice trials. Trends indicate the presence of sexual imprinting effects in the adult preferences of the progeny; however the preferences towards the crest phenotype appear to be weaker than predicted. This would suggest that effects of sexual imprinting on the novel trait are not the only ones at play in development, and the non-parental conspecifics play a more important role in imprinting than previously ascribed.

Winner (tie): Maira Soto, University of California, Irvine
Characterization of Novel Human Beta-Defensins

Beta-Defensins are small cationic peptides that share conserved structure and are secreted by epithelial cells at various mucosal surfaces. Human beta-defensins 1, 2 and 3 inhibit HIV-1 replication at physiological concentrations and therefore may constitute an important component of human innate immunity against HIV-1. Twenty-eight novel human beta-defensin genes remain uncharacterized. We hypothesize that some or all of these uncharacterized beta-defensins have physiologically relevant anti-HIV activity. We have isolated genes encoding nine novel beta-defensins (HBD's- 6, 18, 19, 20, 21, 23, 26, 27 & 29) and have expressed and purified two predicted mature peptides (HBD's- 18 & 26) to near homogeneity. HBD's-19, 23, 27 & 29 have been synthesized using flurenylmethoxycarbonyl solid phase chemistry. Initial investigation into HBD-29, has shown that it exhibits anti-bacterial activity, but seems to increase HIV-1 infectivity. HBD-23 has also shown activity against E. coli, while HBD-27 does not. In order to understand the role of these beta-defensins in innate immunity to HIV-1 and their potential as AIDS therapeutics, we will determine which defensins exhibit the greatest anti-HIV activity and characterize their mechanisms of action.

Environment and Ecology

Winner: Rebecca Aicher, University of California, Irvine
Soil Nitrogen Affects Convergence in Community Composition in California Grasslands

The question of when community assembly is historically contingent with multiple endpoints or deterministic and converges toward a single endpoint has been debated for decades. This study examined how biotic processes interact with environmental conditions to determine the assembly trajectory of plant communities. We hypothesized that species-level negative feedbacks (negative frequency dependence; species population growth rate increases as it becomes rare) cause community-level convergence. Also, we hypothesized that soil nitrogen (N) availability would affect the feedback processes and community composition would converge in high N environments. We tested these hypotheses in 135 one m^2 annual grassland communities that contained 6 species. We varied the initial relative frequency of the species and followed their abundances through time at 3 N levels. Overall species population growth rates were more likely to be negatively associated with initial frequency (negative frequency dependent). In high nitrogen environments, communities converged in composition in comparison to communities at ambient and low N environments, where the community assembly trajectory diverged over time. We conclude that 1) there is evidence that species frequency dependence may be important in determining convergence in community assembly and 2) that N enrichment may increase the likelihood of grassland communities in converging in community composition thereby decreasing regional (beta) diversity.

Honorable Mention: Jaquan Horton, University of California, Irvine
Tough Guts?: The Material Properties of Teleost Intestinal Tissues

Durophagy in fish feeding systems is defined as the ability to consume hard prey. Generally, durophagous fish crush the shells of mollusks and crustaceans before ingestion. Numerous studies have investigated many of the mechanisms and morphologies that enable fish to exploit this trophic niche (e.g. dentition, cranial specializations, and bite force and mechanical advantages). However, few studies have examined the effects of durophagy on visceral tissues. If indigestible shell or exoskeletal fragments are consumed, the material properties of the intestinal tissues must withstand the potential mechanical damage caused by sharp foreign bodies (e.g. shell shards) passing through the gut. In this study, we test the hypothesis that the intestines of durophagous fish are more extensible and less stiff than fish that do not eat hard prey. The whole intestines of six species were inflated using a custom static-pressure system to investigate their material properties. The J-shaped stress-strain curves showed that the initial stiffness ranged from 6 - 60 kPa and that the final stiffness ranged from 4 to 24 MPa. The maximal extension-ratio of the inner lumen ranged between 3.5 and 10.9. This work offers significant insight into the material properties of intestinal tissues in teleost fishes. Future studies will focus on possible adaptive properties of teleost intestinal tissues in a phylogenetic context.

Math, Technology and Engineering

Winner: Ross Barnowski, University of Michigan
Remote Detection of Radioactive Plumes Using Millimeter Wave Technology

One of the most common methods for manufacturing weapons-grade special nuclear materials is the reprocessing of spent nuclear fuel. The reprocessing of spent nuclear fuel for the production of weapons-grade special nuclear materials is accompanied by a release of fission products trapped within the fuel. One of these fission products is a radioactive isotope of Krypton (Kr-85); a pure beta-particle emitter with a half-life of 10.72 years. Due to its chemical neutrality and relatively long half life, nearly all of the Kr-85 is released into the surrounding air during reprocessing, resulting in a concentration of Kr-85 several orders of magnitude higher than typical background (atmospheric) concentrations near the source. The high concentration of Kr-85 is accompanied by a proportionately high increase in air ionization due to the release of beta radiation from Kr-85 decay. A high concentration of ions in air increases the radar cross section due to a combination of atmospheric phenomena, making it possible to detect the presence of Kr-85 induced plumes using millimeter wave (MMW) sensing technology. Possible applications for this technology are obvious; including the remote sensing of reprocessing activities across national borders bolstering global anti-proliferation initiatives. The feasibility of using MMW radar technology to uniquely detect the presence of Kr-85 induced plumes of ions will be tested. Prior to the development of such experiments, the ionizing properties of several feasible lab sources were researched and simplified models for the spatial distribution of ions were developed. The results of these models can be compared with the results of MMW detection experiments to quantify the relationship between radar cross section and air ionization as well as to further calibrate the MMW detection equipment.

Honorable Mention: Alejandro Campos, University of Rochester
Advances in Dust Detection and Removal for Tokamaks

Dust diagnostics and removal techniques are vital for the safe operation of next step fusion devices such as ITER. An electrostatic dust detector developed in the laboratory is being applied to the National Spherical Torus Experiment (NSTX). In the tokamak environment, large particles or fibers can fall on the electrostatic detector potentially causing a permanent short. We report on the development of a gas puff system that uses helium to clear such particles from the detector. Experiments at atmospheric pressure with varying nozzle designs, backing pressures, puff durations, and exit flow orientations have given an optimal configuration that effectively removes particles from a 25 cm area. Similar removal efficiencies were observed under a vacuum base pressure of 1 mTorr. Dust removal from next step tokamaks will be required to meet regulatory dust limits. A tripolar grid of fine interdigitated traces has been designed that generates an electrostatic traveling wave for conveying dust particles to a 'drain'. First trials with only two working electrodes have shown particle motion in optical microscope images.

Medicine and Public Health

Winner: Eric Howell, Texas Tech University
Chemotherapeutic Challenge of the Chernobyl Rodent Apedemeus flavicollis

The disaster at Chernobyl, Ukraine in 1986 has had and will continue to have lasting effects on many different levels. Studies involving epidemiology, environmental impacts, and genetic impacts have been prolific since the accident, revealing some unexpected results on the effects of radiation. Significant findings have been reported as a result of these studies. The long-tailed field mouse, Apodemus flavicollis, was collected from distinct localities representing different populations. These rodents were evaluated based on their response to a number of chemotherapeutic agents. Maximum tolerable doses (MTD) of three different cancer drugs were given to the rodents from three different lifestyles: 1) native mice living and reproducing in a radioactive environment, 2) native mice living and reproducing in an uncontaminated region, and 3) lab mice with no known exposure to radiation. We hypothesize that animals living and reproducing in areas of low-dose radiation contamination will demonstrate a tolerance to the effects of chemotherapeutic agents. This hypothesis is based on the well-studied idea of radio-adaptation, regarding a possible benefit of low-dose radiation. The genotoxic effects will be revealed through the micronucleus assay, karyotypic data, and fluorescent in situ hybridization. If a tolerance is conferred due to low-dose radiation, this study could have a profound impact on the understanding of novel cancer treatments involving low-dose ionizing radiation.

Honorable Mention: Arun Paul, Rosalind Franklin University of Medicine and Science
Therapeutic Potential of COX Inhibitors in Treating Kaposi's Sarcoma Herpes Virus (KSHV) Associated Body Cavity B Cell Lymphoma (BCBL)

BCBL is an aggressive cancer that accounts for 4% of all HIV-associated non-Hodgkin lymphomas with no effective treatments and a prognosis of less than six months. Like other herpes viruses, KSHV life cycle consists of the dormant latent and cytopathic lytic cycle. BCBL is a complex disease of transformed B cells exhibiting KSHV latent cycle. Our earlier studies had shown that KSHV infection induces the pro-inflammatory molecule COX-2 and its metabolite PGE2 and inhibition of COX-2 reduced the latent gene expression. The oncogenic link of COX-2/PGE2 pathway with colorectal, lung, and prostate cancers and the chemotherapeutic potential of COX inhibitors are active areas of investigation. We hypothesize that COX-2/PGE2 pathway plays significant role in BCBL latency and therefore, the pharmacological inhibition of COX in BCBL cells hold immense chemotherapeutic potential. Preliminary work using MTT and apoptotic marker cleaved-caspase 3 demonstrates that COX-2 inhibitor Nimesulide induces proliferation arrest and apoptosis in BCBL cells, respectively. Drug treatment also substantially decreased the protein levels of major KSHV latency protein LANA-1. Ongoing additional work on the effect of Nimesulide on KSHV gene expression and genome maintenance should reveal how KSHV utilizes COX-2 in BCBL pathogenesis which will lead to the use of COX inhibitors in BCBL treatment.

Molecular and Cellular

Winner (tie): Kathleen Mettel, University of Illinois, Urbana-Champaign
Plasticity in the Auditory Thalamus Following Exposure to Complex Acoustic Sequences

Powerful plasticity mechanisms can substantially alter tuning of auditory neurons under

appropriate conditions. Unfortunately, relatively little is known about how plasticity in the auditory thalamus is expressed. To determine if and how plasticity is expressed in the auditory thalamus, I report our preliminary analysis of neuronal data that was recorded from this region (n=7 animals, 251 thalamic sites). A subset of these animals were exposed to a simple spectrotemporal acoustic sequence that consisted of a 12 kHz high-frequency tone (H), a 5 kHz low-frequency tone (L), and broadband noise (N) separated by 100 msec. Exposure to this target sequence was for ~300 times per day for ~25 days. The "H-L-N" sequence was reinforced using chronic deep brain stimulation techniques. Frequencyintensity tuning curve properties were analyzed using a blind procedure to minimize experimenter bias. We analyzed bandwidth, timing in response to tones, response strength, and spontaneous activity. Overall, the preliminary results are encouraging and suggest several significant differences across the entire data set. The results suggest that neurons in the auditory thalamus, like the auditory cortex, show plasticity when exposed to a complex acoustic sequence. The results will be discussed in the context of previous work on experience-dependent plasticity in the auditory system.

Winner (tie): Nagaraj Kerur, Rosalind Franklin University of Medicine and Science
KSHV Infection Induces Inflammasome in Human Monoctytic THP 1 Cells

Kaposi sarcoma associated herpesvirus (KSHV) is etiologically associated with Kaposi's sarcoma (KS) which is characterized by angioproliferative inflammatory lesions consisting of spindle like activated endothelial cells and cytokine rich micro-environment. Cytokines and growth factors are believed to play key roles in KSHV biology including angiogenesis. Early during infection of in vitro target cells, KSHV induces several pro-inflammatory cytokines and growth factors including IL-1, a multifunctional cytokine affecting nearly every cell type that drives a wide range of pro-inflammatory effector networks such as COX-2, phospholipase A, iNOS, PGE2, IL-6 and VEGF implicated in tumor angiogenesis and invasiveness. Realizing the significance of IL-1 and related cytokines like IL-18 and IL-33 in KS, here we examined the KSHV mediated induction of inflammasome, a multiprotein complex regulating the processing and secretion of these cytokines, in human monocytic cell line THP1. KSHV establishes infection in THP1 cells and infection induces IL-1 and IL-18 and various other cytokines. These inductions were dependent on viral genes expression. Our studies demonstrated that KSHV infection induces inflammasome leading to increased secretion of IL-1 and IL-18 that are potentially involved in KS pathogenesis. Further studies are in progress to elucidate the mechanism of inflammasome induction by KSHV.

Honorable Mention: Adriana Garcia, University of California, Irvine
18F-fallypride MicroPET Imaging to Monitor Pancreatic Beta Cell Loss in Diabetes Mellitus

Type-1 diabetes mellitus (T1DM) is an autoimmune disease caused by T-cell mediated destruction of insulin-producing pancreatic beta-cells. Our goal is to develop a non-invasive method to monitor beta-cell loss associated with T1DM. Such a method would improve early diagnosis, provide tools to measure responsiveness to new therapies and evaluate the efficiency of islet graft survival. Dopamine D2 receptor (D2R) are present in rodent and human islets where they co-localize with insulin-containing secretory granules. 18F-fallypride, a ligand with picomolar affinity and a high degree of specificity for D2R, is currently used in positron emission tomography (PET) imaging of the brain. Here we report the use of 18Ffallypride to image beta-cells in the rat. 18F-fallypride binds to pancreatic sections and this binding is competed off by the D2R inhibitor haloperidol, indicating specific binding. Depleting beta-cells by treatment with streptozotocin (STZ) abolishes 18F-fallypride binding. Following intravenous 18F fallypride administration, ex-vivo microPET imaging reveals 18Ffallypride in the pancreas. Thin layer chromatography confirms the presence of fallypride in the pancreas. Co-administration of haloperidol or destruction of beta-cells by STZ decreases the pancreatic fallypride signal. Our results suggest that 18F-fallypride may be a suitable tracer for PET-based monitoring of beta-cell-loss in T1DM and islet transplant survival.

Physical Sciences

Winner: Patrick Brown, University of Notre Dame
Vertically-Aligned Carbon Nanotube Growth for Energy Storage Applications

The impressive mechanical and electronic properties of carbon nanotubes (CNTs) make them ideally suited for use in a variety of nanostructured devices, especially in the realm of energy production and storage. In particular, vertically-aligned CNT "forests" have been the focus of increasing investigation for use in supercapacitor electrodes and as hydrogen adsorption substrates. To investigate these applications, vertically-aligned CNTs were grown on metal substrates by water-assisted chemical vapor deposition. Analysis by scanning and transmission electron microscopy indicated that CNT growth was obtained, resulting in multiwalled CNTs of a wide range in diameter. These microscopy findings were reinforced by Raman spectroscopy, which resulted in a G/D ratio ranging from 1.5 to 3 across different samples, suggestive of multiwalled CNTs. Changes in gas flow rates and water concentration during CNT growth were not found to have a discernable effect on the purity of the CNTs. The specific capacitance of a CNT/FeMo/Inconel® electrode was found to be 3.2 F/g by cyclic voltammetry, and the surface area of a characteristic CNT sample was measured to be 232 m²/g, with a cryogenic (77 K) hydrogen storage of 0.85 wt%. This level of hydrogen adsorption is higher than that predicted by the Chahine rule, indicating that these CNTs bind hydrogen more strongly than typical carbonaceous materials. More work is needed to determine the reason for increased hydrogen adsorption in these CNTs.

Honorable Mention: Amanda David and Augustin Diaz, University of PuertoRico, Rio Piedras
Encapsulation of Insulin into Inorganic Layered Nanomaterials Envisioned as a Drug Delivery System

Inorganic layered materials (ILM), are nanostructured compounds of great interest because of their size, structure, and possible biomedical applications. These materials have been studied in recent years as matrices for several chemical processes such as ion exchange materials and drug delivery systems, among others. Among the most studied ILM are the zirconium phosphates (ZrP) and their different phases. We are focused in the study of the ability of these nanostructured materials to serve as drug carriers of intercalated biologically active molecules of a hydrated phase of ZrP (10.3 Å-ZrP). Particularly, we are interested in the study of how these properties are affected in the nanoenvironment of the intergalleries and how the intercalated materials might be used in biosensors and drug delivery systems. I will present the characterization of insulin intercalated-zirconium phosphate. The intercalation of insulin into the zirconium phosphate layers produced a new phase with a ca. 49 Å interlayer distance, as determined by X-ray powder diffraction data and the FTIR spectrum showed the characteristic bands of insulin in the intercalated material. The XPS data showed that insulin is present in the ZrP galleries and the UV-vis spectrum shows the characteristics bands with a slight red shift. The complete characterization of these materials using analytical techniques will be presented. These materials will be used to develop insulin carriers.

Social Sciences

Winner: Vanashri Nargund, Indiana University
The Influence of Secondary Science Teachers' Beliefs on Classroom Instruction in India

The knowledge and beliefs of a teacher about the nature of science, and the teaching and learning of science greatly impacts science education for a child. However, few studies exist on this subject, particularly in developing regions such as those in South Asia, where basic education including science is crucial to alleviating poverty, reducing inequality and driving economic growth. This study aims to understand how Indian secondary science (ISS) teachers develop their pedagogical content knowledge (PCK), which is defined as the knowledge developed by teachers to help others learn specific content. It is particularly interesting to study contemporary Indian science education because of rapid socioeconomic changes resulting in a blend of the traditional South Asian educational system with its Western counterpart providing valuable insights into how developing nations may use science education for uplifting their society. This qualitative research will compare ISS teachers' beliefs about the roles of science teachers, science teaching and learning strategies for building a scientific foundation with how they are reflected in practice. The preliminary analysis of the interviews and observations showed Indian teachers expressing transitional views about components of PCK but were unable to transfer it to instruction. This research will contribute towards building a framework for science education in India which may provide insight for other developing countries in the region.

Bookmark www.aaas.org/meetings for details on the 2010 AAAS Annual Meeting, 18-22 February. The Poster Submission site opens on 20 July 2009.

The Student Poster Competition recognizes the individual efforts of undergraduate and graduate students working toward a degree. Posters are judged at the meeting. Winners in each category receive a cash award, framed certificate, and AAAS membership. Postdoctoral scholars who hold a doctoral degree are not eligible to enter.