21st Hayes Graduate Research Forum (April, 2007)

Permanent URI for this collection

Submission Instructions for Students

The Arts
1st place: Getzelman, Sarah
2nd place: Getson, Jennifer
3rd place: Wang, Yang

Biological Sciences
1st place: McMichael, Brooke
Description | Full Text PDF (721KB)
2nd place: Sow, Fatoumata
3rd place: Lee, Marianne

1st place: Damaraju, Naga-lakshmi
2nd place: Song, Sangcheol
3rd place: Yang, Lifeng

1st place: Kang, Hana
Description | Full Text PDF (245KB)
2nd place: Cook, Jane
3rd place: Li, Hui

1st place: Kamarajugadda, Sai
2nd place: Nichols, Claire
Description | Full Text PDF (721KB)
3rd place: Kumar, Ankan

FAES and Human Ecology
1st place: Hennessy, Cecilia
2nd place: Subramanian, Anand
3rd place: Mannig, Annegret

1st place: Pagano, Greer
2nd place: Crawford, Patrick
3rd place: Mckain, Aaron

Math and Physical Sciences
1st place: Mack, Gregory
2nd place: Corwin, Luke
Description | Full Text PDF (344KB)
3rd place: Wei, Lai

1st place: Snider, Heidi (Prof Bio Sci)
Description | Full Text PDF (27974Kb)
2nd place: Reveneau, Carine (FAES and HEC)
Description | Full Text PDF (685KB)
3rd place: Young, Nicholas (Bio Sci)
Description | Full Text PDF (1254Kb)

Professional Biological Sciences
1st place: Roberts, Ryan
Description | Full Text PDF (606KB)
2nd place: Gatson, Natosha
3rd place: Seshadri, Sudarshan

Social and Behavioral Sciences
1st place: Mccaslin, Michael
2nd place: Hackett, Michelle
3rd place: Matheny, Roneka


Recent Submissions

Now showing 1 - 8 of 8
  • Item
    GM-CSF Inhibits Breast Cancer Growth and Metastases in Mice and Induces Hypoxia in the Tumor Proper
    (2007-04) Roberts, Ryan; Marsh, Clay
    Background: Scientists have begun to appreciate the important role that normal body tissues play in cancer development and progression. Recent studies demonstrate that cancer cells can trick blood vessels and other cells into helping tumors grow and spread. In 2001, Lin, et al, showed that mice unable to produce M-CSF (a growth factor which stimulates a certain type of immune cell called a macrophage) can still get breast tumors, but these tumors don't spread. We later proved that those findings could be explained, at least in part, by the fact that M-CSF makes macrophages produce and secrete VEGF, a powerful stimulator of blood vessel growth. During these studies, we discovered that another macrophage growth factor, GM-CSF, reduced levels of VEGF by causing these macrophages to release a soluble VEGF receptor (sVEGFR), which binds to VEGF and prevents it from stimulating blood vessel growth. This led us to speculate that treating actual breast tumors with GM-CSF might reduce blood vessel formation and limit tumor growth and spread. The work presented here focuses on characterizing the effects of GM-CSF on tumors and evaluating its therapeutic potential for the treatment of breast cancer. Methods: To test our hypothesis, we injected breast cancer cells into a single mammary gland of normal female mice. After a noticeable breast tumors formed, we began to treat these mice with injections of PBS or GM-CSF into the tumor three times a week. The diameter or the breast tumors was recorded weekly. In a subset of these mice, we also followed oxygen concentration in the tumor using novel imaging methods. At euthanasia, we collected tumor and lung tissues for further analysis. Results: GM-CSF slows the growth of breast tumors and prevents them from spreading in our mouse model. Such effects coincide with reduced oxygen levels and increased cell death within the tumor. PBS-treated tumors demonstrate a single focus of necrosis at the point most distant to the blood supply, near the skin. In contrast, GM-CSF treatment resulted in a multifocal pattern of necrosis with foci distributed across the tumor mass. Co-administration of antibodies directed against sVEGFR with GM-CSF in the same tumor model demonstrated rates of growth similar to vehicle control injections, while isotype antibodies had no effect. Implications: Our data suggest that GM-CSF treatment reduces tumor growth and spread. The mechanism behind this effect includes reduction of available oxygen within the tumor environment, presumably due to release of sVEGFR and subsequent insensitivity to blood vessel growth signals. Importantly, these data show that it may be possible to alter the behavior of normal cells that have been manipulated by cancers to facilitate tumor growth and spread. Not only does this observation present new ideas about ways we might treat tumors, but it also provides new models for studying the mechanisms that underlie blood vessel invasion and the spread of tumors to distant sites.
  • Item
    A Case study: Comparing reading strategies of advanced CFL learners on different genres and media of text
    (2007-04) Kang, Hana; Chan, Marjorie K.M.
    Despite the increasing number of advanced Chinese as a Foreign Language (CFL) learners in American universities, there have been very few investigations of their reading processes and strategies. Most researchers have examined learners’ Chinese character recognition (e.g., Hayes, 1987; Wen, 1995), with the notable exception of Ke’s (1997) study on CFL learners’ approaches to reading. However, Ke (1997) limited the study to one genre of paper-based text (i.e., newspapers) in order to explore the reading processes and strategies of CFL learners. Currently, though, CFL learners engage in various kinds of screen-based hypertext reading, even in the early stages of Chinese learning. Given the lack of research in this domain of reading, it is difficult to generate meaningful discussions about the reading processes and strategies that CFL learners employ. This, in turn, could limit the ability of instructors to teach and evaluate Chinese reading effectively. Therefore, there is a need to examine how CFL learners select and use different reading strategies when engaging in various kinds of Chinese texts (e.g., print-based text and hypertext). This study examined advanced CFL learners’ reading processes and strategies in relation to the different media of texts that they engaged (i.e., print, computer), and a variety of genres of texts (i.e., poetry, essays, textbooks, and newspapers).The research questions were: How do learners utilize different reading strategies? What triggers their application of the same strategy to different texts? To ensure validity, various kinds of data gathering procedures were adopted: in-depth interviews, think-aloud protocols, participants’ marginalia (e.g., notes) in texts, computer mouse movements, and oral summaries of assigned texts. The study revealed that the participants had developed preferences for genres from the early stages of their Chinese learning. Four principal patterns of reading strategies emerged. First, the participants used bottom-up strategies when reading familiar genres in both textbooks and hypertexts. Second, a top-down strategy was generally used by participants for the genres with which they were either unfamiliar or disliked. Third, an interactive model of reading (combined with top-down and bottom-up strategies) was used when they read newspaper articles in print-based texts and hypertexts. Finally, regarding online hypertext-reading, hyperlinks in the texts triggered the application of different strategies. The results suggest that instructors need to provide various genres of texts and explain the characteristics of the different reading strategies available. Moreover, in order to motivate students to read, instructors should introduce different texts through meaningful classroom exercises, such as pre-reading and post-reading activities.
  • Item
    Searching for Physics Beyond the Standard Model with a Rare Decay
    (2007-04) Corwin, Luke; Honscheid, Klaus
    The Standard Model (SM) is the dominant theory of particle physics, which studies the fundamental laws and constituents of the Universe. The SM contains six quarks and six leptons, which are the fundamental particles that constitute ordinary matter. The up, charmed, and down quarks have 2/3 of the electric charge of a proton. The down, strange, and bottom quarks have -1/3 of the electric charge of a proton. The electron, mu, and tau leptons have the opposite electric charge of the proton. For each charged lepton, a neutral lepton known as a neutrino exists. For each of these particles, an antiparticle exists with opposite charge and equal mass. Quarks are always found bound to other quarks. A bound state of a quark and an anti-quark is known as a meson. My analysis focuses on the charged B meson, which consists of an anti-bottom quark bound to an up quark. It is approximately five times as massive as a proton. This meson is very unstable and can decay into many different sets of final particles. The fraction of decays resulting in a given set is called the branching fraction (BF) of that set. I will present the results of my attempt to measure the BF of a charged B meson decaying into a tau lepton and a tau anti-neutrino. The SM prediction for this BF depends on several variables, of which one (fB) has not yet been measured; it quantifies the proximity of these two quarks in a bound state. This decay currently provides the best test of the SM prediction for fB. By attempting this measurement, I also test the BF prediction from the SM. Pairs of charged B mesons are produced by the PEP-II collider at the Stanford Linear Accelerator Center via collisions of electrons and anti-elections (known as positrons) at high energies. Data from these collisions are collected by the BaBar detector. BaBar has the shape of a large hexagonal prism surrounding the collision point. It consists of several concentric subsystems designed to detect different particles and properties, such as momentum and energy. This analysis is difficult because neutrinos rarely interact with matter, so they cannot be detected by BaBar. To overcome this difficulty, I employ and refine a technique that accounts for all detectable results of the decay. I search through BaBar's current data set, which contains more than 300,000,000 charged B mesons, for those events with missing momentum and energy most consistent with undetected neutrinos. I find 245 events in the signal region where 221.7 ± 12.7 background events were expected. The resulting BF is (1.0 ± 0.6 ± 0.1) x 10E-4, where the first error is statistical and the second is systematic. This is 1.3 standard deviations above zero, which is not a statistically significant measurement, but an upper limit can be placed on the BF at the 90% confidence level of 1.8 x 10E-4. This result is a confirmation of the SM, which predicts a BF of (1.6 ± 0.4) x 10E-4, and restricts the options available for theories beyond the SM.
  • Item
    Regulation of Invasiveness of Glioblastoma Multiforme Cell Lines and Tumor Stem Cells by Sphingosine Kinase and Sphingosine 1-Phosphate Reveals Potential Molecular Therapeutic Targets
    (2007-04) Young, Nicholas; Van Brocklyn, James
    Glioblastoma Multiforme (GBM), the most common primary brain tumor in adult patients, is a grade IV astrocytic neoplasm characterized histologically by high mitotic index, significant angiogenesis, necrosis, and local invasion. This infiltrative nature leads to inevitable tumor recurrence even after conventional radiation and chemotherapeutic treatment. With a median patient survival of less than one year, there is a great need for a better understanding of the molecular basis of these malignant behaviors in order to develop effective molecular based therapies. We have been investigating the role played by the bioactive lipid sphingosine-1-phosphate (S1P) in GBM. S1P stimulates growth, motility, invasiveness, angiogenesis, and adhesion in a variety of tumor cell types. We have previously shown that S1P stimulates growth and invasion of glioma cells through its receptors (S1P1-3) which are commonly expressed in GBM tissue. In addition, we have also shown that high levels of the enzyme responsible for S1P production, sphingosine kinase (SphK), correlate with *poorer survival of GBM patients. This study uses receptor manipulated GBM cell lines to delineate the contributions of the various S1P receptors to the malignant behavior of well established GBM cell lines. The results show that S1P1 and S1P3 stimulate growth, motility, and invasion. S1P2 also stimulates GBM cell growth. Although S1P2 decreases GBM cell motility, surprisingly it increases invasion, by enhancing attachment to extracellular matrix material. This unusual enhancement of invasion by S1P2 also required upregulation of the matricellular protein CCN1/Cyr61, since this effect was blocked by neutralizing antibodies against this effector molecule. Furthermore, we have begun to investigate the role of S1P in both normal neural stem cells and brain tumor stem cells (BTSC) derived from GBM tissue. BTSC are a subpopulation of cells present in GBM which, unlike traditional GBM cell lines, form tumors in animal models that resemble GBMs histologically and invade into surrounding brain tissue. BTSC are likely the formative cells of GBM tumors and may be derived from the transformation of normal neural stem cells. Spheroid invasion assays show that S1P stimulates invasion of both BTSC and neural stem cells, while SphK inhibitors block the invasion of BTSC. These data suggest that these cells are highly responsive to S1P and that enhanced SphK in GBM BTSC could drive the invasion of these cells. In summary, our data identify downstream mediators of S1P in GBM cells that may mediate enhanced malignant behavior of these tumors. Several of these mediators may be useful as therapeutic targets. In addition, our data implicate S1P and SphK in the invasiveness of the crucial BTSC.
  • Item
    Elucidating the Role of Macrophages in Visceral Leishmaniasis
    (2007-04) Snider, Heidi; Satoskar, Abhay
    Background: Leishmaniasis is a tropical disease caused by protozoan parasite species belonging to the genus Leishmania. Depending on the infective species, leishmaniasis can manifest as one of three major disease states – cutaneous, mucocutaneous or visceral. L. donovani causes visceral disease with tropism for reticuloendothelial organs. Left untreated, L. donovani infections are fatal, often due to secondary bacterial infections and complications resulting from profound hepatosplenomegaly. Leishmania species parasitize host cell macrophages, the cell type that is ultimately responsible for killing parasites under correct immune conditions. Experimental mouse models that mount type I CD4+ T cell (TH1) responses are capable of activating macrophage populations to effectively kill parasites and exhibit a healing response. However, mice that mount type II CD4+ T cell (TH2) responses are unable to effectively activate macrophage populations and experience chronic, non-healing disease. Purpose: Recently our laboratory found that two important transcription factors involved in TH1 cell signaling, STAT-1 and T-bet, unexpectedly play distinct roles in determining the outcome of visceral leishmaniais caused by L. donovani. We showed that STAT-1 knock-out (KO) mice, which are highly resistant to L. donovani infection, recruit fewer macrophages into their livers following infection compared to susceptible wild-type and T-bet KO mice. This result led us to study the effect of treating mice with clodronate, a drug that selectively depletes macrophages, both pre- and post-infection with L. donovani. The purpose of this study was to determine the effect of macrophage depletion in mice infected with L. donovani. Research Methods: Mice were treated with clodronate 2 days prior to infection, or at either 1 day or 6 days post-infection. At timepoints ranging from day 7 to day 22 post-infection, livers and spleens of mice were harvested. At each timepoint, impression smears of the livers were taken to determine parasite burdens, sections of livers were prepared for immunohistological analysis, and liver lymphocytes were isolated and analyzed via flow cytometry. In addition, splenocytes were isolated, stimulated with soluble L donovani antigen, and cytokine production was determined using ELISA. Findings: Mice treated with clodronate both pre- and post- infection showed markedly reduced parasite burdens compared to PBS treated controls. In addition, mice that were treated with clodronate both pre-infection and one day post-infection showed little or no immunopathology compared with PBS controls. However, mice treated 6 days post-infection showed immunopathology similar to PBS controls, despite having significantly reduced parasite burdens. In addition, mice treated pre-infection had reduced levels of all cytokines measured (IL-4, IL-10, IL-12, and IFN-gamma) compared to PBS treated controls, whereas mice treated post-infection had reduced levels of all cytokines except IL-4 when compared to PBS treated controls. Implications: This research indicates that the depletion of macrophages at early timepoints post- L. donovani infection is able to reduce both parasite burdens and immunopathology associated with disease. This research may serve as a foundation in determining whether macrophage selective-drugs represent viable treatment options for human diseases that chronically infect host cell macrophages, such as leishmaniasis and tuberculosis.
  • Item
    Tropomyosin 4 Regulates Osteoclast Function through Actin Adhesion Structures
    (2007-04) McMichael, Brooke; Lee, Beth
    Osteoclasts, large, multinucleated cells which resorb bone, function to maintain bone degradation vital for maintenance and repair of bone tissue. Osteoclasts function by forming unique actin structures for migration, podosomes, and bone resorption, actin rings. The actin cytoskeleton also transports V-ATPases to the plasma membrane. Thus regulation of actin is central to the understanding osteoclast function. Tropomyosins are proteins that bind to actin and regulate other proteins association with actin. The purpose of this study is to investigate the role of tropomyosins, specifically tropomyosin 4, in osteoclasts. Our research initially demonstrated the presence of eight tropomyosins in osteoclasts. Confocal imaging demonstrated that the eight tropomyosins were distributed in distinct locations. Of these eight tropomyosins, tropomyosin 4 colocalized with the interior faces of both actin rings and podosomes. To investigate the role of tropomyosin 4 expression was suppressed by RNA interference. The suppression led to reductions in actin ring thickness, bone resorption, and motility. Suppression also led to improper V-ATPase trafficking which was not due to a decrease in expression or complex formation. In addition, we produced stable cell lines that overexpressed tropomyosin 4. Overexpression resulted in abnormal podosomes that were thicker than normal and unusually distributed along with reduced cell motility. Further, actin ring formation was disrupted and bone resorption was abolished. Together the studies suggest that tropomyosin 4 regulates the adhesion structures of osteoclasts by stabilizing the actin in podosomes and actin rings and thus affecting osteoclast migration and resorption.
  • Item
    Interactions of unsaturated fat or coconut oil with Rumensin® on milk fat production might be mediated through inhibition of specific protozoal genera
    (2007-04) Reveneau, Carine; Firkins, Jeffrey L.
    Polyunsaturated fatty acids (PUFA) feeding often decreases protozoal numbers in the rumen. Animal-vegetable fat (AV), a by-product of the food industry, is readily available to provide PUFA in dairy diets. However, the response to AV supplementation on protozoal numbers is not consistent, possibly due to biohydrogenation (BH) of PUFA in the rumen. Long chain saturated FA are less toxic to protozoa; therefore, the BH of PUFA removes their potential inhibitory effects. In contrast, evidence from OSU supports the contention that protozoa are a vehicle for passage of PUFA or other intermediates of BH that do not promote MFD. AV supplementation in combination with Rumensin® (R), an ionophore improving feed efficiency, occasionally spontaneously decreases milk fat yield and percentage. This milk fat depression (MFD) is likely due to the partial BH of PUFA, which favors FA intermediates that are inhibitory to milk fat synthesis. Feeding coconut oil (CO) rich in medium chain fatty acids (MCFA), and therefore low in PUFA, has decreased the abundance of ruminal protozoa in sheep. We hypothesized that, while lowering protozoal populations, diets supplemented with CO in combination with R would not cause MFD as would AV diets combined with R. PUFA or MCFA in combination with R could shift ruminal fermentation and potentially depress fiber degradation, reducing fed intake.
  • Item
    Observations of Wave-induced Vortices over Ripples
    (2007-04) Nichols, Claire; Foster, Diane
    Our understanding of vortex generation over rippled beds is largely based on small-scale laboratory studies. The insight provided by such studies has been considerable, although questions remain regarding the applicability to the field. This paper presents observations from a full-scale investigation of wave-induced vortex generation events over a movable sediment bed. Observations of the two-dimensional time varying velocity field were obtained with a submersible Particle Image Velocimetry (PIV) system in a field-scale, experimental environment at the O. H. Hinsdale Wave Research Laboratory. The observations were obtained over an irregularly rippled bed with ripple heights of 0.01 m and wavelength of roughly 0.1 m. The vortices generated during offshore directed flow over the steeper bed form slope were regularly ejected into the water column. The observations allowed for an examination of the generation and subsequent ejection of individual vortical structures. Vortical structures are identified with a measure of the flow field that estimates the time for a complete revolution of a vortice called swirling strength. An analysis of these structures reveals that the swirling strength non-dimensionalized by the wave period is correlated to the Keulegan-Carpenter. These results offer new insight into fluid sediment interaction over rippled beds.