Festival of Scholars

An annual celebration of research, scholarship, and creativity

April 27 - May 1, 2015

Natural Science Oral Presentations

Date: Thursday, April 30, 2015
Time: 12:30pm - 2:00pm
Location: Richter Hall
Description: This session will highlight students from various disciplines within the Natural Science Division. Each student will give a 15-minute oral presentation using PowerPoint. These stimulating presentations will reflect months of work on a single project which has likely been presented at a discipline-specific professional conference.

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Student Abstracts at this Session

Jared Berman

Faculty Mentor:
Dr. David Marcey
Roles of SOCS36E Inactivation in extra eye and Oncogenesis in Drosophila melanogaster

The Janus Kinase/Signal Transducer and Activator of Transcription (JAK/STAT) pathway governs numerous developmental processes in Drosophila melanogaster, and irregularities in its expression have been linked to physical anomalies and solid tumor oncogenesis. JAK/STAT signaling is of interest because it holds close homologies to development and pathogenesis in human systems. In Drosophila, extra eye (ee) is an incompletely penetrant, variably expressed mutation located on chromosome 2L. The penetrance of ee phenotypes increase as JAK/STAT activity is up-regulated. SOCS36E is a known feedback inhibitor of the JAK/STAT pathway.
A main purpose of this study is to characterize SOCS36E function by analyzing the effects on ee penetrance and tumor proliferation when SOCS36E is inactivated. Analysis of F1 generations from crosses of ee by two SOCS36E loss-of-function mutations, referred to here as 33106 and 35896, revealed ee penetrance values of 1.08% and 1.82%, respectively. These values were significantly greater than 0.50% ee penetrance in wild type control crosses.In addition, over-activation of the JAK/STAT pathway by SOCS36E loss of function resulted in increased oncogenesis. Evaluation of six crosses for oncogenic phenotypes in the presence of HopTum-l and SOCS36E mutations indicated that lines 33106 and 35896 yielded tumorigenic phenotypes with penetrance values of 11.00% and 13.50%, respectively. Penetrance values for wild type crosses (1.50%) and ee crosses (3.00%) were lower. These studies suggest that SOCS36E operates normally to coordinate development by regulating JAK/STAT signals and possesses tumor suppressor characteristics.

Fransheska Berrios

Faculty Mentor:
Dr. John Deisz
A Study of Electron Lifetime in the Large Underground Xenon Dark Matter Detector

Direct detection of dark matter is the primary goal of the Large Underground Xenon (LUX) experiment. Evidence for the existence of dark matter has been derived from observations of phenomena in the universe that are seemingly caused by unseen matter. One candidate for dark matter is the weakly interacting massive particle (WIMP). The LUX detector, a dual-phase (liquid-gas) time projection chamber (TPC) located 4850ft under ground at the Sanford Underground Research Facility in Lead, South Dakota, aims to detect WIMPs through their interaction with regular matter. The goal of this project was to develop computer algorithms to determine the electron lifetime in the LUX detector. The electron lifetime was determined for seven data sets obtained from metastable Krypton 83 calibration runs and the lifetimes were then compared to analyse fluctuations over time. We determined that the electron lifetime is sufficiently high so that electrons generated by WIMP interactions in a liquid xenon target will be able to reach the detector. The work also brought to light issues in the way data from the detector is processed.

Heidi Ferkranus
and Heather Nony, Johnston Wang, Tyler Berg

Faculty Mentor:
Dr. Michele LeBlanc
Effect of Gender and Landing Direction on Knee Joint Kinematics and Kinetics During Drop Landings

Previous research has identified factors that may contribute to ACL injury, including gender, improper landing mechanics, and landing direction. Drop landings are frequently used to determine the kinematics and kinetics associated with landing mechanics. Most studies involve landing in a forward direction, but recent work in our laboratory has shown that landing direction influences both peak ground reaction forces (Cyprian and LeBlanc, 2008) and frontal and sagittal joint angles (Berg and LeBlanc, 2014).  The purpose of this study was to compare the effect of landing directions and gender on lower body kinetics. Thirty physically active subjects (15 M, 15 F) age 18-25 years participated in this study. Drop landings were performed from a 60 cm box with kinematics captured with a Vicon 6-camera motion capture system (120 Hz) and kinetics collected with two Kistler force plates (1200 Hz). Trials were performed from six equal distance directions (Right, Diagonal Right, Forward with Left foot, Forward with Right foot, Diagonal Left, Left) with direction order randomized.  3-dimensional angles at the hip, knee and ankle for the lead leg were calculated from touchdown (TD) to maximum knee flexion (LP) with five clean trials per direction averaged for analysis.  Knee joint kinetics and kinematics were analyzed with a two-factor ANOVA (p < 0.05) with post hoc tests using Bonferoni. 

Courtney Hong

Faculty Mentor:
Dr. Christopher Brown
Mathematical Modeling of the Hypothalamic-Pituitary-Adrenal Axis

This project is an analysis of models of the hypothalamic-pituitary-adrenal (HPA) axis.  The HPA-axis is the system responsible for cortisol regulation in the human body.  Hormones of the HPA-axis fluctuate with circadian and ultradian rhythms.  As a study of a biological system, the results of this project have implications in disciplines beyond mathematics.  In our study we analyze models that address the ultradian rhythms of the axis, believed to be an intrinsic characteristic of the system.  We look at three models, the ``Minimal Model'' (Vinther 2011), a model including hippocampal mechanisms (Vinther 2013), and a patient-specific model (Ottesen 2014).   In each of the papers the authors' attempts to create oscillating solutions have varying degrees of success.  A brief overview of the three models and analyses is given.  Finally we present a new model of the system that expands upon the three models.

Brittany Smolarski

Faculty Mentor:
Dr. Jason Kingsbury
Expansion of a Pyridinyl Cross-Coupling Methodology to New Pharmacologically-Active Substrates

In our previous work on the scaled-up syntheses of pyridinium-based dye molecules, we identified unique conditions for the palladium-catalyzed cross-coupling of pyridinyl compounds.  We are now curious whether our methodology will prove to be a general solution to the synthesis of diverse, highly-substituted pyridines.  Specifically, we aim to explore the scope of our cross-coupling within a new class of chiral terpyridine ligands, which themselves will be used to synthesize medium-ring azacycles.  The latter type of substructure has been implicated in a host of pharmacological applications including treatment of bronchitis, tuberculosis, pertussis, pain, and thrombosis.  Despite much research, the availability of an approach to building versatile, enantiopure azacycles continues to remain elusive, highlighting the need for improved synthetic methods. We have prepared in high yield the ferrocenyl pyridine substrates that represent a supreme test of our cross-coupling method due to steric hindrance.  This background work entailed synthesizing pyridines with a 2-chloro (or 2-bromo) substituent fused to a cyclopentadienyl surrogate.  The ferrocene domain was then installed by standard, one-pot treatment of FeCl2 with a pyridinyl lithium salt. Subsequent exposure to a suitable boronic acid nucleophile under conditions of our previously-mentioned Suzuki cross-coupling reaction, will hopefully generate the targeted terpyridine ligands.  These novel ligands can then be applied to the catalytic production of stereodefined aziridines. Using the characteristic ring strain present in aziridines, a previously unexplored tandem reaction sequence involving the 3-Aza-Claisen, ring-opening rearrangement under Takai-olefination conditions will be tested for the preparation of medium-ring azacycle compounds.

Taelor Young

Faculty Mentor:
Dr. Kris Karsten
No Sexual Dimorphism in Bite Force and Sprint Speed in Uta stansburiana

Bite Force and sprint speed are important performance traits in many species. Sprint speed is vital for the survival of males and females (escaping predators), while bite force is critical for males maintaining their territories (winning fights via biting opponent). I examined males and females of Uta stansburiana lizards to determine if there was sexual dimorphism (differences between the sexes) in bite force and sprint speed. I also investigated whether or not there was a correlation between bite force and sprint speed in males. I collected data using a force transducer for bite force and a track for sprint speed. As a lizard sprinted from one side of the track to the other, sensors placed 0.25 m apart were activated. Sprint speed was determined by dividing the distance between sensors by the time traveled between sensors. There was no sexual dimorphism in animal performance: males and females had statistically similar bite force and sprint speed. There also was no correlation between bite force and sprint speed in males; thus, no trade-off existed between bite force and sprint speed. A larger bite force (larger head) did not equate to a slower sprint speed. Currently, I am examining spectral color data to determine if a correlation exists between throat color and bite force and/or sprint speed.