Tag: Poster 15

Movement Direction and Shoulder Orientation Alter Elbow Joint Position Sense

Presenter: Tayson Heward

Mentor: Andy Karduna

AM Poster Presentation

Poster 15

Proprioception is the body’s ability to sense its position and movement without visual input. Proprioception of the elbow and shoul- der has been shown to be most accurate when elevation or flexion angles are at 90 degrees. Investigations in shoulder orientation and movement direction may lead to a better understanding of what is playing the largest role in this heightened sense at 90 degrees. This study looks at the effects of shoulder orientation and movement direction on elbow joint position sense (JPS). With an aim to look at what is increasing proprioceptive acuity as you increase flexion angle to 90 degrees, we predicted that an increase in shoulder orientation would increase elbow JPS, but movement direction would have little effect on JPS. Subjects had the same 3 target angles; 50, 70, and 90 degrees, that the subjects would memorize their elbow position then actively mimic the position. There were two different 2-way interactions found; one between angle and orientation, and another between movement direction and shoulder orientation. This indicates that elevating your shoulder to 90 degrees increases elbow JPS. Also, extension at the elbow may be lead to better elbow JPS than flexion, yet shoulder orientation possibly negates this effect. Analysis is ongoing and further conclusions are in development for this study.

Tracing the Endocardial Cell Lineage of Developing Heart Valves Using MADMMatter Pools?

Presenter : Amy Jones

Mentor : Kryn Stankunas

Major : Biology, Human Physiology

Poster 15

Heart valve development is a complex, multi-step process. During development, endocardial cushions form at specific locations in
the early heart tube. These cushions are populated by endocardial cells that delaminate in a process known as epithelial-mesenchymal transformation (EMT). In the mouse, EMT takes place between embryonic day 9.5-10.5. It is a vital process to understand since the heart valves are derived from this cardiac cushion tissue. Current models of cushion EMT suggest that a large number of endocardial cells undergo EMT. An alternative hypothesis is that only a few individual cells initially populate the cushions that then proliferate to expand cushion mesenchyme.To better understand how endocardial-derived cells contribute to heart valves, I am using a novel mouse genetic system termed MADM (mosaic analysis with double markers). MADM uses the Cre-lox system to permanently label specified cells by fluorescent protein expression. For my studies, I use the Tie2 promoter to direct Cre expression and instruct the MADM system to specifically trace the endocardial cell lineage. The low frequency by which labeled cells are generated allows me to exquisitely moni- tor contributions of clonally-related endocardial cells to developing valves. By gaining a complete understanding of the contribution of endothelial-lineage cells to developing valves, we can identify when embryonic heart malformations originate, supporting the development of therapeutics to prevent defective valves from progressing to a diseased state.

Perchlorate, Oxidative Stress and Thyroid Proliferation in Threespine Stickleback

Presenter: Connor Fitch

Mentor: William Cresko

Poster: 15

Major: Biology 

Perchlorate is a water contaminant that has been detected in drinking water across the U.S. Severe health effects result from exposure to high levels of perchlorate. Our lab has shown that perchlorate causes several abnormalities
in fish, including increased thyroid proliferation in stickleback and zebrafish. We aim to determine the molecular basis of perchlorate’s effects on thyroid development and cell proliferation. Two hypotheses for increased cell proliferation include activation of Wnt signaling pathways, and perchlorate reduced expression of miR-16, miR-24, and miR-195, a group of microRNAs that suppress cell proliferation. We hypothesize that perchlorate causes direct damage by increasing oxidative stress in threespine stickleback, subsequently activating Wnt pathways and leading to cell proliferation. In order to test for the presence of oxidative stress, we performed an assay to calorimetrically quantify the presence of malondialdehyde (MDA)—a known oxidative stress biomarker. Forty stickleback embryos (20 control, 20 chronically exposed to 100ppm perchlorate) between 100-150 days post fertilization were analyzed for MDA. Perchlorate significantly increased the presence of MDA by 0.34μM in the treated group, correlating to a 13% increase of MDA over the control group. This supports our hypothesis that perchlorate causes oxidative stress in fish. Perchlorate causes a multitude of abnormalities during development and our data demonstrate that oxidative stress may be one contributing factor. Currently we are performing qPCR analysis to determine the involvement of SOD, tp53, and axin2a/b in oxidative stress from perchlorate. In addition, we are using qPCR to examine if perchlorate decreases expression of miR-16, miR-24, and miR-195. These data will help us to determine a molecular connection between perchlorate and oxygen radicals on interruption of normal thyroid function.

Silver Tip Preparation for Scanning Tunneling Microscopy

Presenter: William Crowley

Mentors: Ben Taber and George Nazin, Chemistry

Poster: 15

Major: Chemistry

Scanning tunneling microscopy (STM) can be utilized to image, manipulate, and spectroscopically characterize individual atoms and molecules. The scanning probe used in STM is often described as a tip. Tips are conically shaped pieces of metal that are, ideally, atomically defined at one end. Creating well defined tips is essential to obtaining quality STM images. Due to its spectroscopic enhancing plasmonic properties silver is an interesting material for STM. Specifically, enhancements to the factor of 106 to 107 have been reported. The Nazin group has developed a novel method of electroetching sliver to produce well defined STM tips. In our process we utilize a previously unused electrolyte; 1:8 glacial acetic acid to deionized water. Our two-step process first involves an automated primary electrochemical etch in which a 0.5 mm 9.9985% silver wire is etched to form a rough conical shaped. Second, the roughly shaped silver wire is manually etched to produce a well-defined apex. My research has focused on optimizing and parametrizing variables in this two-step process such as voltage bias and rate of etching. Finished tips are then characterized by scanning electron microscopy and energy dispersive x-ray spectroscopy. This process has yielded tips with an apex of approximately 200 nm.

A University of Oregon Substance Use Survey: An Analysis of Substance Use among Sexual and Gender Minority Students

Presenter: Patrick Glang

Faculty Mentor: Jake Mahon

Presentation Type: Poster 15

Primary Research Area: Social Science

Major: Psychology

College students who identify as lesbian, gay, and bisexual are more likely to use substances (Cochran, Ackerman, Mays, & Ross, 2004). Few studies have assessed both substance use and perceived risk of substance use in specific sexual orientation and gender identity groups. This study examined (1) the rates of substance use and (2) associated perceived risk of substance use among male, female, and transgender sexual minority students. A web-based survey assessing substance use, sexual orientation, gender identity, and perceived risk of substance use was administered to students from the University of Oregon (UO). A total of 5928 students (27% of UO population) responded to the 180-item survey. Over 9% of students identified as a sexual minority (n = 536) and 2.5% of students identified as a gender minority (n = 194). Group differences are discussed across sexual orientation and gender identity subsamples, as well as correlates associated with student substance use. Implications of this study point to potential higher risk of substance use and abuse among college students who identify as sexual and gender minorities. More research is needed to isolate causal risk factors for substance use issues within student subpopulations, and to better understand the relationship between gender, sexual orientation, and substance use.

Optimization of Deposition Techniques for Thin Film Production and Analysis

Presenter(s): Madelyn Scott − Chemistry

Faculty Mentor(s): Cathy Wong, Kelly Wilson

Poster 15

Research Area: Physical Chemistry

Funding: Community for Minorities in STEM (CMiS) Travel Award Scholarship; Phil and Penny Knight Campus for Accelerating Scientific Impact

Organic semiconductors offer a green alternative to conventional conductive materials because they can be solution- processed on an industrial scale for use in solar cells and OLEDs. The electronic transitions in organic semiconducting materials determine their charge-carrying efficiency for use in such devices. Transient absorption spectroscopy can be used to track the population of mobile electron-hole pair combinations at controlled delay times after photogeneration by a laser pulse. This technique is typically used to study equilibrated systems, like static solutions or films, but not materials as they evolve. For in situ studies of non-equilibrated systems, the Wong Lab has developed a single-shot transient absorption (ssTA) spectrometer to measure the excited state dynamics of thin films during deposition by a capillary or slot die coater. The solution capillary is two microscope slides spaced by aluminum shims and housed in an aluminum frame. The slot die coater is an apparatus designed to mimic solution-processed films that are manufactured roll-to-roll on an industrial scale. In both deposition techniques, a mechanical slide pusher is attached to the deposition device and positioned over an aluminum
stage to produce films on microscope slides. Experimental parameters considered during optimization of each deposition method included the following: slide pusher velocity, cleaning methods of the deposition slides, temperature of the depositing solution, and materials constructing the slide pusher apparatus. It was determined that the slot die coater enables more control over film quality than the solution capillary, producing films with more homogenous solution coverage. As a result, the slot die coater will be incorporated into the spectroscopy apparatus for the first in situ ssTA measurements of non- equilibrated material systems.

Using the Auxin-Inducible Degron System to Reversibly Switch Caenorhabditis elegans Populations Between Outcrossing and Exclusively Self-fertilizing Reproduction.

Presenter(s): Paula Berry 

Faculty Mentor(s): Megan Moerdyk-Schauwecker & Patrick Phillips

Poster 15

Session: Sciences

Inducibly switching the reproductive mode of a model multi-cellular organism would be a powerful tool with many applications in genetic, reproductive and evolutionary studies. The nematode Caenorhabditis elegans is a functional hermaphrodite, with most individuals in wild- type strains being self-fertile, somatic females. However, non-disjunction events during meiosis cause occasional males to appear in a population, also allowing for sexual reproduction (outcrossing). Using CRISPR/Cas9, a degron tag was added to a key sex determination protein, XOL-1. XOL-1 could then be targeted for degradation by the proteasome by placing the C. elegans strain on plates containing auxin (Indole-3-acetic acid), a plant hormone. This caused all male embryos to become non-viable, and created an exclusively self-fertilizing population. Unlike xol-1 null mutants, which cannot be switched back to producing viable males, this effect was easily reversed by moving individuals to a non-auxin containing plate, restoring outcrossing. This method enables the maintenance of exclusively self-fertilizing lines with outcrossing potential with less labor than existing methods, using benign chemicals. Furthermore, the creation of this strain gives finer controls over experiments by allowing the same, genetically identical, populations to be self-fertile or outcrossing in a controlled manner.