1941 research outputs found
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"Indole derivatives interact with DOPC in Langmuir monolayers"
No full textMelissa Brozik and Erin Frazee are students at Drake University. Maria Bohorquez is Associate Professor of Chemistry in the College of Arts and Sciences at Drake. She can be contacted at [email protected] interactions between indole derivatives and 1,2-di-oleoyl-sn-glycero-3-phosphocholine (DOPC) were studied using a Nima Langmuir-Blodgett (LB) trough. A 0.25 M phosphate buffer sub-phase was used with a physiological pH range of 7.31-7.48. The air-phosphate buffer interface was examined at room temperature. Constant ionic strength was maintained by 0.100 M potassium chloride (KCl). Two different indole derivatives were used, indole and tryptophan, in concentrations of 3.0 uM and 5.0 uM. It is evident when examining the isotherms that the DOPC monolayer is expanded in the presence of indole derivatives, as the area per molecule was increased by 0.02nm2/molecule.Drake University, College of Arts and Sciences, Department of Chemistry, and NSF Grant 0311325
"Counting all the SHEEP": A summary of the past and present work associated with ASCA’s The Search for the High-Energy Extragalactic Population (SHEEP) survey.
Get PDFTim Weinzirl is a junior at Drake University, majoring in Physics and Astronomy. He presented this poster session at DUCURS (Drake University Conference on Undergraduate Research in the Sciences) held on the Drake campus on April 15, 2005.SHEEP is the Search for the High-Energy Extragalactic Population, a survey of X-rays sources found in 5-10 keV band images from the ASCA satellite. Because hard X-rays are difficult to obscure, SHEEP provides a largely unbiased accounting of the AGN population. We have been identifying SHEEP using new high-resolution Chandra images, and following up with deep optical imaging from Greece and near-infrared imaging from Wyoming. Spectral classifications are obtained at NOAO 4-meter telescopes. Our initial work shows a wide variety of optical classes, ranging from QSOs to optically normal galaxies (despite their high X-ray luminosities). We have also identified several high-redshift quasar pairs, which is intriguing given the size of the sample. Completion of identifications and classifications will permit us to finally "count the SHEEP" and provide a better picture of the AGN population and the sources contributing to the X-ray background.Sponsored by Drake University Office of the Provost, Drake University College of Arts and Sciences, Drake University College of Pharmacy, Iowa Space Grant Consortium/NASA, Drake University Departments of Biology, Chemistry, Environmental Science and Policy, Mathematics and Computer Science, Physics and Astronomy, and Psychology
"Hierarchical routing in sensor networks using κ-dominating sets "
Get PDFMichael Q. Rieck is an associate professor at Drake University in Des Moines, Iowa, USA. He holds a Ph. D. in mathematics from the University of South Florida. His primary research interests are in the areas of camera tracking and ad hoc wireless networks. He has also published results in the areas of triangle geometry, discrete mathematics, linear algebra, finite fields and association schemes.For a connected graph, representing a sensor network, distributed algorithms for the Set Covering Problem can be employed to construct reasonably small subsets of the nodes, called k-SPR sets. Such a set can serve as a virtual backbone to facilitate shortest path routing, as introduced in [4] and [14]. When employed in a hierarchical fashion, together with a hybrid (partly proactive, partly reactive) strategy, the κ-SPR set methods become highly scalable, resulting in guaranteed minimal path routing, with comparatively little overhead. © Springer-Verlag Berlin Heidelberg 2005
"The Impulse and physics of movement"
Get PDFThis sabbatical paper was written in 2002 by now retired Associate Professor of Theatre Arts, Sally Garfield. Garfield taught theatre classes at Drake for 23 years. In this paper she reflects on her own dance education experiences, as well as what she was successful in teaching at Drake
"Do restored wetlands create suitable waterfowl habitat?"
No full textScott H. Anderson is a student at Drake University. Keith S. Summerville is an Assistant Professor in the Department of Environmental Science and Policy at Drake.Historically, North American wetland ecosystems supported substantial waterfowl biodiversity prior to agricultural development. Loss of wetland habitats in agricultural states such as Iowa is often linked to regional declines in breeding waterfowl, and the restoration of open water wetlands is increasingly used to increase waterfowl habitat. While several studies have examined whether restored wetlands function as habitat for spring migrating waterfowl, data on fall habitat use is lacking. The goal of this study was to determine if restored wetlands functioned as suitable habitat for a diversity of waterfowl species. We hypothesized that natural wetlands would have greater species richness and abundance of waterfowl compared to restored wetlands. We also tested whether waterfowl community composition was a function of differences in environmental variables among wetland sites (hydroperiod, wetland age, percent cover and height of emergent vegetation). To test these hypotheses, we performed point counts of waterfowl populations in four restored and four natural wetlands in central Iowa. We observed 10 species of waterfowl using these wetlands, and we also detected a significant correlation between species occurrence and wetland habitat quality. Total abundance of waterfowl was marginally higher on natural wetlands compared to restored wetlands. Waterfowl habitat use also appeared to be a function of wetland hydroperiod and, perhaps the percent cover of vegetation surrounding any open water. Thus, our data suggest that the most critical factors to consider when managing a restored wetland for fall migrating waterfowl are to maintain consistent hydroperiods and increased cover of emergent vegetation.Drake University, College of Arts and Sciences, Department of Environmental Science and Policy
"2' hydroxycinnamaldehyde exhibits potential as an anticancer chemotherapeutic agent"
No full textMegan Strenk graduated from Drake in May 2005, with a B.S. in Biochemistry, Cell and Molecular Biology. Lisa Fuller is currently a Pharmacy student at Drake.In recent years, complementary and alternative medicine (CAM) has become more widespread in the treatment of a variety of illnesses. Several of these alternative herbal therapies claim that they are effective in fighting cancer, though these claims have yet to be supported by the FDA. It is our goal to develop an assay that can evaluate the efficacy of some of these herbal treatments against cancer. Thus far, our main focus has been on the compound hydroxycinnamoaldehyde (HCA), which is the active ingredient in the herb Rou Gui. We have looked at the efficacy of this drug using two methods. The first, flow cytometry, uses DNA to determine cell death. The second, a caspase-3 assay, surveys for a protein present in early apoptosis. These two assays have allowed us to find a dose-response curvefor 32D cells using two traditional concer treatments (Taxol and Doxorubicin), each with and withoutthe addition of HCA. The difference in the curves for each drug with and without HCA will tell us whether or not the herbal has an effect for that treatment.Drake University, College of Arts and Sciences, Department of Biochemistry, Cell and Molecular Biology, and the College of Pharmacy. Des Moines University, Department of Physiology and Pharmacology
"Distributed routing algorithms for multi-hop ad hoc networks using d-hop connected d-dominating sets"
Get PDFMichael Q. Rieck is an associate professor at Drake University in Des Moines, Iowa, USA. He holds a Ph. D. in mathematics from the University of South Florida. His primary research interests are in the areas of camera tracking and ad hoc wireless networks. He has also published results in the areas of triangle geometry, discrete mathematics, linear algebra, finite fields and association schemes.This paper describes a distributed algorithm (generalized d-CDS) for producing a variety of d-dominating sets of nodes that can be used to form the backbone of an ad hoc wireless network. In special cases (ordinary d-CDS), these sets are also d-hop connected and has a desirable “shortest path property”. Routing via the backbone created is also discussed. The algorithm has a “constant time” complexity in the limited sense that it is unaffected by expanding the size of the network as long as the maximal node degree is not allowed to increase too. The performances of this algorithm for various parameters are compared, and also compared with other algorithms
"Species traits as predictors of the frequency of recolonization in prairie Lepidoptera"
No full textRenae M. Steichen and Christopher Conoan are students at Drake University. Keith S. Summerville is Assistant Professor of Environmental Science and Policy in the College of Arts and Sciences at Drake.Restoration ecologists are increasingly turning to the development of models to predict how species move from a regional species pool into a restored community. Two untested assumptions of these models, however, are that ecologists have an understanding for which traits are predictors of species distribution and that such traits predictably interact to determine the community membership. The goals of this study were to sample the regional species pool of Lepidoptera and to determine whether combinations of species traits predispose species toward becoming members of the actual species pool within restored prairies. In 2004, we sampled 259 moth species from 13 Tallgrass prairie remnants and restorations in central Iowa. We used principle components analysis (PCA) to identify significant combinations of ecological traits that were shard by large groups of moth species and found that the model explained 81.6% of the variance. Species most frequently filtered from the regional species pool into prairies were those that: (1) had long flight periods and were multivoltine (2) displayed a feeding preference for legumes but not the Asteraceae or other forb families, and (3) were regionally abundant but relatively small in body size. Analysis showed significant differences in moth community composition among prairie sites, suggesting trait differences among species partly drive patterns of turnover among prairie sites. Finally, our results suggest that a combination of random and deterministic mechanisms interact to determine how moths attain community membership within restored habitats, and that these processes may operate relatively slowly for univoltine forb specialists with restricted distributions.Drake University, College of Arts and Sciences, Department of Environmental Science and Policy
"Detection of PIGF protein in neonatal rat cardiomyocytes"
No full textMarin Schweizer, Kyle Bohman, Carrie Mittelstedter and Ben Colton are all Drake University students. Ronald J. Torry is Associate Professor of Pharmacology at Drake University. Donald S. Torry is on the faculty at Southern Illinois University School of Medicine.Angiogenesis, the formation of blood vessels, can provide blood to the heart when its normal arteries are compromised. Angiogenesis is highly dependent on the Vascular Endothelial Growth Factor (VEGF) family. Placental Growth Factor (PlGF) is a member of this family and is crucial for pathological angiogenesis in the adult. PlGF coupled with the more common VEGF could greatly increase angiogenesis in the heart tissue, thus providing oxygen to ischemic heart tissue. Previous research has shown that PlGF mRNA increases with six hours of hypoxia which models ischemia. However, not much is known about PlGF expression on the protein level. We intend to establish that PlGF protein expression will increase in rat cardiomyocytes which have undergone 6, 12 and 24 hours of hypoxia compared to normoxic rat cardiomyocytes. This information will later be used in studies of potential protective treatments using PlGF.Drake University, College of Pharmacy and Health Sciences, Department of Pharmaceutical Sciences
"External validation of the Runco Ideational Behavior Scale"
No full textMaria Clapham is Associate Professor of Psychology at Drake University and can be reached at [email protected]. Both Laura Muchlinski and Holly Sedlacek major are Psychology majors, graduating from Drake in May 2005.The Runco Ideational Behavior Scale, RIBS, was recently created as a tool for assessing ideation.
It is intended as a useful criterion for measuring divergent thinking, which includes originality, fluency, and flexibility. While studies have shown that the RIBS has internal consistency, there is no evidene for how it relates to other measures of creativity. This study compared the RIBS to two other creativity tests, How Do You Think (HYDT)and the Torrance Figural Test of Creative Thinking (TTCT) to examine convergent validity. Each test was given to 72 students at a private midwestern university. The students were either introductory psychology students or advanced painting students, 46 were female and 26 were male. There was no statistically significant relationship between the RIBS and the TTCT, showing no convergent validity between the two tests which claim to measure the same construct. Contrary to expectations, there was large significant correlation between the HDYT and the RIBS. These results suggest that the RIBS and the TTCT do not measure the same construct. The strong positive correlation between RIBS and HDYT scores suggests the RIBS measures constructs similar to those of the HDYT. This brings into question the usefulness of the RIBS as a measurement of divergent thinking.Drake University, College of Arts and Sciences, Department of Psychology