Tag: Poster 22

Characteristics of Menstrual Cycle Manipulation with Combined Hormonal Contraception in a University Student Population

Presenter: Hannah Lakehomer

Mentor: Chris Minson

PM Poster Presentation

Poster 22

The purpose of this study was to assess the frequency and characteristics of menstrual cycle manipulation with combined hormonal contraception (CHC) among a population of college-age women. A self-administered email survey on menstrual cycle practices and beliefs was distributed to all female students at the U of O. Assessment of participant characteristics, menstrual cycle manipulation features, and attitudes/knowledge toward CHC was analyzed using standard statistical methods and probit models. Of respondents, 79.9% reported using CHC currently or recently and 20% of these women reported altering their menstrual cycle pattern or using ex- tended cycle regimens to delay/skip their menstrual periods. Of cycle manipulators, 47% indicated that they learned this practice from healthcare professionals, while about 30% indicated their source of information was from family or friends. Women taking CHC for period regulation, of Asian race, on a regular exercise program, and who preferred to menstruate monthly were less likely to manipulate their menstrual cycle. The likelihood of menstrual cycle manipulation increase dasfemaleage increased. Women whoused the pill, who preferred to menstruate less than monthly, and who felt fairly knowledgeable about their CHC were more likely to manipulate their menstrual cycle. In conclusion, a significant percentage of university-aged women who use CHC choose to manipulate their menstrual cycle and the characteristics of these women may predict probability of this choice.

Predicted SH3 Binding Motif in Drosophila aPKC is Required for Proper Localization of aPKC During Asymmetric Cell Division of Neuroblasts

Presenter : Ryan Boileau

Mentor : Ken Prehoda

Major : Biochemistry, Human Physiology, Human Biology

Poster 22

Asymmetric cell division of Drosophila neural stem cells, neuroblasts, require the proper localization of factors that influence the orientation of cell divisions and future fates of mitotic progeny. Errors in the generation of this polarity could cause cells to overproliferate and become cancerous. In neuroblasts, atypical protein kinase C (aPKC) has been previously shown to be a key mediator in the genera- tion of apico-basal polarity by localizing to the apical cortex and restricting fate determinants Numb and Miranda to the basal cortex during cell division. This allows the dividing neuroblast to maintain pluripotency while also generating a daughter cell that differenti- ates into neurons. Although the mechanism of how aPKC restricts basal determinants has become transparent, we seek to evaluate how aPKC itself is apically localized. Using a combination of genetic and biochemical approaches, we have found that a predicted SH3 binding motif within aPKC is necessary for apical polarization. We hypothesize that an SH3 domain containing protein binds to aPKC at this site and plays a role in stabilizing apical localization. Future research will be focused on finding interacting partners of this SH3 binding motif using a candidate gene-based approach.

Variation of Self-sorting Behavior and Jaw Bone Morphology in Early Development within Chinook Salmon (Oncorhynchus tshawytscha)

Presenter: Natasha Mckibben

Mentor: Charles Kimmel

Poster: 22

Major: Human Physiology

Research at Oregon State University has shown that two types of juvenile fish are present in a hatchery stock of spring run Chinook salmon derived from locations along the Upper Willamette River Basin in Oregon. The two groups differ in body morphology, agonistic behavior, growth, and whether they live at the surface or the bottom of the water column. However, they maintain the same diet and identical rearing conditions under captivity. The juveniles appear to resemble wild fish rearing in downstream and upstream sites in the Willamette River Basin respectively, and leave their home streams for the main stem of the river during the same time of year each wild group does. Based on understanding in another species, stickleback, I hypothesize that the fish growing at different depths also differ in their feeding strategies and, therefore, might exhibit changed jaw morphologies and mechanics, even though the genetic basis is unknown. To test this prediction, I quantitatively compared lower jaw bone morphologies in the two types of juveniles at the 50 mm stage. Supporting my hypothesis, I found significant differences between the groups in the shapes of both lower jaw bones, the angular-articular and the dentary. No difference was present in the bone sizes relative to body size. These results provide further evidence that early differences in behavior may be predictive of juvenile life history tactics.

Characterization of Inputs to Active Basolateral Amygdala Neurons after Different Behavioral Treatments

Presenter: Harrison Fontaine

Mentors: Leah Deblande and Clifford Kentros, Institute of Neuroscience

Poster: 22

Major: Biology and Human Physiology

The amygdala is a brain structure that is required for the acquisition and storage of fearful memories. In humans, abnormal amygdalar activity has been associated with post-traumatic stress disorder, anxiety, and depression.
One component of simple fear memory formation is the association of a fearful stimulus and an otherwise neutral predictive stimulus. This association occurs in the basolateral amygdala (BLA). While the main inputs to the BLA
are well characterized, the specific coding strategies these inputs use to convey information has not been detailed. We used transgenic mice in conjunction with a modified viral tracer to determine how the inputs to recently active BLA neurons varied after exposure to fear-inducing and non-fear-inducing situations, with the reasoning that if different inputs were labeled after different treatments, inputs must be employing a neuron-specific coding strategy. In addition, we examined the differential activity of neurons in the BLA that may be gating the formation of fear memories. We reasoned that if these neurons were differentially active between fear-inducing and non-fear-inducing situations, these neurons might indeed be gating fear memory formation. Our results supported the use of a neuron- specific coding strategy in BLA input regions, as well as the model of a subset of BLA neurons gating fear memory formation. These results elucidate aspects of fear memory circuitry, and thus have implications in treating fear circuit pathologies.

Stable Oxygen Isotope Analyses and Proxy Validation for Shellfish Foraging and Paleoenvironmental Reconstructions from Chelechol ra Orrak, Palau, Microesia

Presenter: Mila Lassuy

Co-Presenters: Taylor N. Dodrill, Nicholas P. Jew, Scott M. Fitzpatrick

Faculty Mentor: Nicholas Jew, Scott Fitzpatrick

Presentation Type: Poster 22

Primary Research Area: Science

Major: Archaeology, Public Relations

Funding Source: National Science Foundation; Sasakawa Peace Foundation; Sigma Xi

In Palau, Micronesia, marine resources such as shellfish played a vital role in subsistence for millennia. At the Chelechol ra Orrak site, nearly 100 shellfish species have been identified in archaeological assemblages, but there is a dearth of data on nearshore paleoecology or prehistoric shellfish foraging practices. To address these issues, we employed stable oxygen isotopes (δ18O) on select shellfish species, which has been successfully applied in many coastal regions to reconstruct paleoenvironments and sea-surface temperature (SST). In this study, modern shellfish samples were collected from intertidal zones near the site and ambient SST recorded. We then used X-ray diffraction on the samples to identify the skeletal biomineralogical composition, which provides the necessary information to select the proper isotope-to-SST conversion formula. Calcium carbonate samples were milled from modern shells and the δ18O results paired with ambient water temperatures using several δ18O-SST conversion equations. Using the most appropriate formula, these equations were then applied to δ18O samples from several prehistoric shells to reconstruct a high-resolution SST. Results provide useful baselines for examining a host of issues related to prehistoric subsistence strategies in Palau and how environmental changes may have influenced the availability and productivity of various molluscan taxa through time.

Properties and Synthesis of Three Component Heterostructure: (BiSe)1+δ(Bi2Se3)1+ δ (BiSe)1+ δ (TiSe2)

Presenter(s): Alexander Lygo − Physics, Chemistry

Faculty Mentor(s): David Johnson,

Poster 22

Research Area: Natural/Physical Science

Funding: Vice President for Research and Innovation (VPRI) Undergraduate Fellowship, Presidential Undergraduate Research Scholars program

As potentially applicable in high-performance electronics and quantum computers, topological insulators and heterostructures containing them have recently garnered significant interest by materials scientists. Despite their imagined utility, these compounds have proven difficult to synthesize. In a recent study of a series of compounds, [BiSe1+δ]m[TiSe2] m with m = 1, 2, 3, it was observed that, for the m = 3 compound, the topological insulator Bi2Se3 formed upon deposition and was present at all annealing temperatures. To test if Bi2Se3 could be incorporated into a heterostructure, a series of (Bi- Se)3-TiSe2 precursors with varying Bi-Se ratios and layer thicknesses were prepared and annealed at various temperatures for 30 minutes. A combination of specular and in-plane diffraction indicated that select precursors formed a highly crystalline and crystallographically aligned compound containing BiSe, Bi2Se3, and TiSe2 and high-resolution electron microscopy revealed the stacking sequence of the constituents. X-ray fluorescence measurements reveal that the compound formed readily over a range of Bi-Se ratios. Electron transport measurements revealed metallic behavior and surprisingly high carrier mobility, compared to BiSe1+δ TiSe2. These results provide a synthetic route for preparing a high quality Bi2Se3 containing heterostructure with unexpected properties and with further research, a material with properties applicable to electronics or quantum computers may be discovered.

The Effect of Varying Reward Treatments on Performance and Learning Acquisition in Mice

Presenter(s): Minh Nguyen

Faculty Mentor(s): Laura Boddington & Paul Steffan

Poster 22

Session: Sciences

An animal’s ability to learn and perform perceptual tasks is highly variable, depending on factors such as reward type. Using a more favorable reward is expected to positively influence motivation and performance. The present study examined the effects of using a highly palatable caloric reward in lieu of standard water reward. It was hypothesized that a high caloric reward solution would facilitate a faster learning rate on an auditory discrimination task. Surgically head- posted mice were habituated and put on water restriction prior to behavior sessions. They were trained in a “tone-in-noise” detection task with 10% sucrose solution reward for correct licks and time out (resetting trial) for incorrect licks. We recorded the animal’s performance while simultaneously monitored the pupil dilations. The results showed that 10% sucrose solution has the capacity to act as a reward stimulus due to its positive reinforcement properties, however, larger sample sizes are required to fully quantify the efficacy of sucrose solution compared to traditional fluid rewards. By examining the effects of alternative reward treatments on performance in an auditory discrimination task, we can determine optimal treatment conditions in which mice learn most efficiently. These results could further elucidate the relationship between caloric intake, nutrition, and arousal.