Tag: Poster 4

Histological Characterization of Changes in Skeletal Muscle during Tourniquet Induced Ischemia and Reperfusion

Presenters: Aaron Boothby and Arman Ameripour

Mentor: Hans Dreyer

PM Poster Presentation

Poster 4

Orthopedic surgeons often utilize a tourniquet during surgical procedures to minimize blood loss and to maintain a clear surgical field. Current clinical dogma is that tourniquet use for up to two hours has no lasting negative impact on muscle tissue. However, our lab has recently shown that tourniquet use downregulates proteins regulating components of the cap-dependent translation initiation and elongation complex and upregulates proteins regulating catabolic pathways (MuRF1 and MAFbx) as well as stress activated protein kinases (SAPK/JNK). Tourniquet induced-anoxia reduces the rate of muscle cell metabolism. Studies have shown that the resultant ATP deficit leads to failure of the sodium potassium pump and subsequently to the building up of intracellular sodium and chloride ions. This change in ionic concentration causes water uptake and cell swelling. In this study, we used immunohistochemistry to analyze morpho- logical changes in muscle cells resulting from tourniquet-induced ischemia and subsequent reperfusion. We hypothesize that tourniquet use will result in muscle cell swelling. Preliminary data supports our hypothesis. Further research is needed to examine the role that cell swelling may play in post-surgical atrophy.

Electron Diffraction in a Scanning Electron Microscope

Presenter : Alexander Schachtner

Mentor : Benjamin McMorran

Major : Physics

Poster 4

We use focused ion beam nanofabrication to manufacture forked diffraction gratings capable of producing electron beams with helical wavefronts and orbital angular momentum (OAM). A vast number of unique beam modes carrying OAM can be produced through manipulation of grating fork number or position. Generally these gratings are milled such that they produce a phase shift in the beam and are used with high energy electrons (300keV) in a TEM to investigate the quantum or magnetic properties of the electron or image magnetic materials. Our latest work focuses on manufacturing gratings that produce only an amplitude shift, which opens up imaging capability to lower energy electrons (5-30 keV) and thus expands their use to a wider range of commercially available SEMs. We use these amplitude gratings to show the relationship between the number/position of forks and OAM inherited by the beam. This work could lead to advances in imaging capability, and also creates a widely accessible and scalable demonstration of the quantum properties of the electron which can be leveraged by any science program with SEM access.

Mandible Morphology and Habitat in the Extant Tribes Marmotini and Sciurini (Rodentia:Sciuridae)

Presenter: Eva Biedron

Mentor: Samantha Hopkins

Poster: 4

Major: Geology/Biology

Morphological convergence among rodents living in similar habitats is common and well recorded. While upper incisor angle has been studied in connection with diet, lower incisor angle has been relatively neglected, despite textbook assertions that it correlates to habitat. Due to the difference in diets and jaw use between the terrestrial tribe Marmotini and the arboreal tribe Sciurini, it is expected that the tribes will display different mandible morphology, specifically lower incisor angle and diastema depth. The inclination of the lower incisor was quantified by measuring its angle relative to the occlusal surface of the lower molars with the mandible in lateral view. Diastema depth was measured as a vertical line along the anterior edge of the mental foramina, again viewing the mandible laterally. Preliminary data supports a relationship between smaller lower incisor angles and arboreality (t22 = 2.652, p = 0.015), but does not support diastema depth (t12 = 0.375, p = 0.714) as a predictor of arboreality. Changing habitats during the early Oligocene could have prompted the radial evolution of sciurids; by understanding how modern squirrels’ morphology is related to the habitat they live in, paleontologists will be able to better reconstruct a fossil squirrel’s paleoenvironment by using measurements of commonly preserved cranial elements as a proxy for actual habitat data.

Characterizing Genetic Relationships Underlying Adaptive Flower Color Divergence in Mimulus aurantiacus

Presenter: Connor Benson

Mentors: Matt Streisfeld and Sean Stankowski, Biology

Poster: 4

Major: Biology

Understanding the genetic basis of adaptive traits lends insight into the mechanisms that generate biodiversity. Flower color has been implicated as an adaptive trait in numerous studies, and is thought to be a primary driver
of speciation in angiosperms due to selection by differential pollinator preference. Here I used molecular genetic techniques to examine the relationship between two regulatory genes involved in the production of red floral pigment, a trait thought to underlie the evolution of two new subspecies in Mimuls aurantiacus. I used genotype-phenotype comparisons in lab bred plants to characterize how MaMyb1, the less studied of these two genes, impacts the production of red floral pigment. I also utilized virus-induced gene silencing in an attempt to understand the functional role of MaMyb1 in producing red flowers. My results thus far suggest that MaMyb1 does not play a significant role in producing red flower pigment. This work aims to better our understanding of the genetic relationships underlying flower color divergence in an important model system for the study of speciation.

Muffled Voices: Press Censorship in the Former Soviet Union

Presenter: Jonathan Bach

Faculty Mentor: Peter Laufer, Kim Sheehan

Presentation Type: Poster 4

Primary Research Area: Humanities

Major: Journalism

Funding Source: The University of Oregon-UNESCO Crossings Institute, Airfare to Azerbaijan; the University of Oregon College of Arts and Sciences, $1914.26 for airfare; the Government of Azerbaijan, hotel and occasional food

Around the globe, countries suffer from constrained media outlets and a lack of access to public information. In the former Soviet Union, there has been a struggle to maintain a balance between media autonomy and censorship. Such censorship hinders reporters’ roles as watchdogs against the government, free to uncover corruption without fear of a threat to their lives. But as I found through research in and outside of Azerbaijan—a country on the Caspian Sea—those at the top of the government come down harshly on journalists who are just doing their jobs. So that I could better understand the ways in which censorship occurs, I conducted interviews via my research fellowship with the University of Oregon-UNESCO Crossings Institute for Conflict Sensitive Reporting and Intercultural Dialogue with journalists and academics in Oregon and Finland. For this thesis, I draw on my experience at the World Forum for Intercultural Dialogue in Baku, Azerbaijan, as well as the experiences of journalists who have worked on press freedom issues in countries like Ukraine. For example, I spoke with Steve Bass, President and CEO of Oregon Public Broadcasting, about his time in Kiev, Ukraine, working with national broadcasters there to develop a cohesive national public station. I also spoke with Juan Barata Mir, who works with the Organization for Security and Cooperation in Europe, about the ways in which external officials put pressure on governments like Azerbaijan to release jailed journalists. It’s a common fact that the public has a right to access official information—so when that right’s impeded, there must be backlash.

Decompression Experiments of the Mono Craters Eruptions of 1340 C.E.

Presenter(s): Eamonn Needham − Earth Sciences

Faculty Mentor(s): Jim Watkins, Thomas Giachetti

Poster 4

Research Area: Earth Sciences (Geology)

Funding: UROP mini grant

The Mono Craters, California eruptions of 1340 C.E. were a series of eruptions that produced relatively texturally homogeneous deposits, with the exception of the first bed. The initial eruptive deposits differ from later deposits in
the relative abundance of obsidian pyroclasts (quenched magma), volatiles (H2O and CO2), and microlites (minerals <100μm). These textural differences between Bed 1 and the other beds remain unexplained, but may be due to changes in decompression rates. To test the decompression rate hypothesis, a sample of synthetic Mono obsidian was run in a cold seal pressure vessel at eruptive conditions. The sample was kept at 850°C and 60 MPa for 2.5 days, and then was decompressed isothermally at a rate of 0.001 MPa/s until it reached 5 MPa. Following rapid quench, bubble number density and microlite number density were determined from scanning electron microscope images. In the future, more of these experiments will be run at different decompression rates, to see which decompression rate best match the textures of the Bed 1 samples. The calculated decompression rate will be compared to decompression rates of later deposits which were calculated in other studies using volatile concentrations. If Bed 1 has a different decompression rate than the later beds, this could explain the textural differences, and can be used to look at how the eruption initiated and progressed. This research could have implications for the ongoing debate of eruptive style transitions from explosive to effusive, which in turn will inform hazard mitigation for volcanoes exhibiting this behavior.