AJUR Volume 15 Issue 1 (June 2018)

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AJUR Volume 15 Issue 1 (June 2018)


Links to individual manuscripts, abstracts, and keywords are provided below.


p.5 An All-Atomistic Molecular Dynamics Study to Determine the Structural Importance of Disulfide Bonds in Immunoglobulin G and Bovine Serum Albumin


Akshay Mathavan, Akash Mathavan, Michael E. Fortunato, & Coray M. Colina
ABSTRACT: A fully-atomistic molecular dynamics study was performed to determine the importance of disulfide bonds on the stability of immunoglobulin G (IgG) and bovine serum albumin (BSA).The transferability of a previous prescreening methodology to assess contributions from individual disulfide bonds on conformational stability was tested on both proteins. In IgG, it was apparent that inter-chain and intra-chain disulfide bonds play different roles in maintaining structure, evidenced by clear separation of inter-chain cysteine residues upon cleavage of disulfide bonds. In BSA, a set of double disulfide bonds required both to be broken in order to observe significant structural changes, equivalently seen in a previous study of human serum albumin (HSA), a structurally similar protein. Structural analysis of IgG showed deviations in distances between domains, while analysis of BSA suggested more local structural changes. This work helps confirm the efficacy and reproducibility of the prescreening methodology on both a novel, larger protein such as IgG and a more homologous (to HSA), globular protein such as BSA. The results provide insight into the role of specific disulfide bonds in the stability of IgG and BSA.
KEYWORDS: Molecular Dynamics; Atomistic Simulations; Immunoglobulin G; Bovine Serum Albumin; Disulfide Bonds

p.23 Syndecan Affects Odor Response as well as Learning and Memory in Drosophila melanogaster


Dena Arizanovska, Jonathan King, &Karl G. Johnson
ABSTRACT: Syndecan (Sdc) is a transmembrane heparan sulfate proteoglycan that plays a crucial role in axon guidance and synapse formation during CNS development in Drosophila melanogaster. To further examine the effect of syndecan on CNS function, Sdc23 mutant D. melanogaster larvae were used to examine odor preference and the capacity for learning and memory. A series of olfaction assays in both wild type and mutant larvae were performed to characterize naive odor responses before adding a training period to identify the capacity for associative learning. These results showed that Sdc23 larvae prefer odors that wild type larvae do not respond to, suggesting a difference in odor receptor pathways and wiring. In addition, associative learning has been documented in wild type larvae, yet no evidence of associative learning in Sdc23 larvae was found, suggesting that the syndecan also plays a role in learning and memory in D. melanogaster larvae.
KEYWORDS: Syndecan; Proteoglycans; Neurodevelopment; Axon Guidance; Olfaction; Attraction Index; Associative Learning; Drosophila

p.33 Investigation of Flow Rate on Chemical Bath Deposition of Silver Films Inside Hollow Polymer Cylinders


M. Ehrsam, H. Taz, A. Malasi, C. Carr, & R. Kalyanaraman
In thin film solar cells made as planar structures, the absorption of solar light and hence, the solar conversion efficiency, is heavily determined by the position and orientation of the sun. One way to overcome this is to use solar cell geometries that could better absorb sunlight from different angles. One potential geometry is a hollow cylinder, which has the ability to better absorb the sun’s rays incident at various angles due to the light trapping nature of the cylindrical geometry. If such solar cells could be fabricated inside polymer tubes with micrometer diameters, many potential applications built around non-woven or woven textiles could be realized. Here we investigate the deposition of homogeneous thin metallic films inside hollow polymer cylinders using the process of chemical bath deposition (CBD). Although films deposited via CBD have been studied extensively, mechanisms to achieve high quality deposition inside hollow cylinders are still not well understood. The objective of this project was to deposit a smooth, homogeneous silver film inside a hollow cylindrical structure using varying flow rates. The early stage film growth for very short deposition times was observed by the localized surface plasmon resonance of the silver nanoclusters via absorption spectra along the length of the tube. For longer deposition times, silver films formed and were analyzed for their morphology, thickness, roughness, and resistance using a combination of optical microscopy, scanning electron microscopy, and two-probe conductivity. The findings from this study showed that deposition under flow with different Reynolds numbers had a strong influence on the morphology and electrical resistance of the deposited films.
KEYWORDS: Thin-films; Chemical Bath Deposition; Nanoparticles; Solar Cells; Silver

p.43 Feasibility of Man-Portable Power Generation Systems


Earl C. Allen & Nelson Fumo
ABSTRACT: Electric power is the most common source of power for many portable devices used in outdoor recreation, emergency scenarios, and military applications. Batteries that have limitations regarding power and energy are currently meeting the power demand for most of these devices. There is a search to use alternative power sources for portable energy needs. This search has mostly been researched particularly for the military to satisfy functions necessary for soldiers. However, any alternative that would provide electricity in an efficient and timely manner is useful in many applications beyond the military. The feasibility of man-portable power generation systems using thermal energy from any kind of fuels needs to be studied further, to understand if they are truly an option for situations where batteries are currently used. In this study, the feasibility of fueled power systems is investigated. Commercially available small power systems show that they are not small enough to satisfy the definition of man-portable power system. However, power systems working on an internal combustion engine show to be a better option when compared to batteries and fuel cells.
KEYWORDS: Fueled Power Generation; Man-portable Power; Power Density; Energy Density

p.55 The Role of Gender Stereotypes in Gubernatorial Campaign Coverage


Karen Bjerre
ABSTRACT: Through a content analysis of 1,152 articles covering 20 different gubernatorial races between 2004 and 2014, I examine how the presence of a woman candidate in a gubernatorial race affects media coverage of that campaign. This paper considers the prevalence of gender biases and stereotypes and examines whether print media outlets perpetuate these stereotypes or subvert them. Existing research suggests that voters favor traditionally masculine traits over traditionally feminine traits when evaluating candidates for public office. The difference in media coverage may therefore influence women’s chances of getting elected, and thereby influence women’s descriptive and substantive representation. I find that races with a woman candidate receive less issue coverage and more horse race coverage than races with two men running. Additionally, the types of adjectives used in campaign coverage differ depending on the gender of the candidate: women are more likely to be described as able to “change government,” while men are more likely to be described as “experienced.”
KEYWORDS: Media Coverage; Gender; Gubernatorial Campaigns; Women in Politics; Gender Stereotypes; Newspaper Coverage; American Politics