Unraveling How Candida albicans Forms Sexual Biofilms.

Biofilms, structured and densely packed communities of microbial cells attached to surfaces, are considered to be the natural growth state for a vast majority of microorganisms. The ability to form biofilms is an important virulence factor for most pathogens, including the opportunistic human fungal pathogen Candida albicans. C. albicans is one of the most prevalent fungal species of the human microbiota that asymptomatically colonizes healthy individuals. However, C. albicans can also cause severe and life-threatening infections when host conditions permit (e.g., through alterations in the host immune system, pH, and resident microbiota). Like many other pathogens, this ability to cause infections depends, in part, on the ability to form biofilms. Once formed, C. albicans biofilms are often resistant to antifungal agents and the host immune response, and can act as reservoirs to maintain persistent infections as well as to seed new infections in a host. The majority of C. albicans clinical isolates are heterozygous (a/α) at the mating type-like (MTL) locus, which defines Candida mating types, and are capable of forming robust biofilms when cultured in vitro. These "conventional" biofilms, formed by MTL-heterozygous (a/α) cells, have been the primary focus of C. albicans biofilm research to date. Recent work in the field, however, has uncovered novel mechanisms through which biofilms are generated by C. albicans cells that are homozygous or hemizygous (a/a, a/Δ, α/α, or α/Δ) at the MTL locus. In these studies, the addition of pheromones of the opposite mating type can induce the formation of specialized "sexual" biofilms, either through the addition of synthetic peptide pheromones to the culture, or in response to co-culturing of cells of the opposite mating types. Although sexual biofilms are generally less robust than conventional biofilms, they could serve as a protective niche to support genetic exchange between mating-competent cells, and thus may represent an adaptive mechanism to increase population diversity in dynamic environments. Although conventional and sexual biofilms appear functionally distinct, both types of biofilms are structurally similar, containing yeast, pseudohyphal, and hyphal cells surrounded by an extracellular matrix. Despite their structural similarities, conventional and sexual biofilms appear to be governed by distinct transcriptional networks and signaling pathways, suggesting that they may be adapted for, and responsive to, distinct environmental conditions. Here we review sexual biofilms and compare and contrast them to conventional biofilms of C. albicans

Fundamental characterization of unbound base course materials under cyclic loading

ABSTRACT Pavements are a layered system each layer distinguished by different materials as required by traffic and subgrade conditions. A base course is an intermediate layer constructed of high quality stone aggregates: quality based on physical properties such as gradation, hardness, and texture. Although indicative of performance, physical properties do not directly measure performance. This thesis presents the results of a comprehensive experimental testing program that was conducted to examine the behavior of unbound granular base materials under cyclic loading and to evaluate the effect of the stress level and moisture content on strain behavior. Three base materials, namely granite, limestone and sandstone, were selected. Different physical properties tests were conducted on the materials considered. In addition, static and repeated load triaxial (RLT) tests were performed in this study. Three different types of RLT tests were used including: resilient modulus, single-stage, and multi-stage RLT test. The single-stage and multi-stage RLT tests results were analyzed within the framework of the shakedown theory. The results of this study showed that for resilient modulus the materials preformed the following, with the materials listed highest to lowest: limestone, granite and sandstone; while for permanent deformation, the materials were listed highest to lowest: sandstone, limestone and granite. In addition, the results demonstrated that the change in slope (m) of shakedown limits with the degree of saturation was more pronounced at lower stress levels (elastic limit) than that at higher stress levels (plastic limit). Finally, the results showed a significant effect of degree of saturation on the intercept of the shakedown limits at both low and high stress levels. The change in intercept was greater for limestone than sandstone for changes in degree of saturation

Studying the Variability of Dying Stars

In this project, we are observing and analyzing the light variability in a class of dying stars. This involves observing then on clear nights, primarily at the Valparaiso University Observatory but also including a few nights at the SARA Telescope at Kitt Peak National Observatory in Arizona. Thus far this summer we have observed for 25 nights and we observed 31 stars. Some of them we observed on every clear night and others we observed once or twice a week. We are analyzing a subset of 18 of these. We find that they have varied in light by 12 to 74% over the four years of observations. So far, periods have been found for 8 out of 18 objects, and they range from 50 to 315 days, based on the data collected before May 2012. These variations are due primarily to the pulsation of the stars. The goal is to find the amplitude and period of the variations; these can be used to investigate the internal structure of the stars

A Study of Light Variability in Dying Stars

In this research project, we observed and analyzed the light variability in a class of dying stars that are in the stage between Red Giant and White Dwarf in the evolution of stars like the Sun. Our observations were carried out during the summer and fall of 2012 at the Valparaiso Observatory. Thirty-two of these objects were observed in total. We analyzed a subset of 18 of these and found that they all varied in visual brightness by 10-70 percent. Periods for the variability were found for 8 out of 18 objects, and they range from 27 to 125 days, based on five years of observations. These variations are due to the pulsation of the stars. The goal is to find the amplitude and period of the variations; these can be used to investigate the internal structure of stars. This research was supported by a grant from the National Science Foundation

Analyzing Multidisciplinary Team Effectiveness in an Engineering Environment: A Case Study of the West Point Steel Bridge Design Team

The West Point Steel Bridge Design Team is a group of five undergraduate seniors working to design and build a steel bridge for the annual ASCE Steel Bridge Competition. The purpose of our group’s research is to discover how multidisciplinary teams perform in academically competitive environments. This project provides a unique opportunity in the field of multidisciplinary collaborative work because the team’s success can be objectively measured against this year’s competitors and the team’s performance in previous years. The traditional structure of the West Point team consisted of three-to-five civil engineering majors. This year’s team includes a law and legal studies major and five civil engineers, two of which recently switched from systems engineering. Past designs have relied heavily on the work of previous years, which has led to stagnant performance at competitions. Our hypothesis is that by entering different perspectives into the group at an early stage, a revolutionary approach will ensue and overall performance will increase. The team did not completely disregard the designs and methods of previous teams, but the reliance on their decision-making process was more heavily scrutinized with the current multidisciplinary team. Our research is not solely limited to competitive performance. We also analyzed the decision-making process of this year’s team in comparison to previous years. While data on decision-making is not readily available, both the faculty advisor and two current team members who served on the team last year were able to provide personal insight into how the teams compare. Ultimately, this research seeks to provide groups in similar academically competitive environments an indication of whether a multidisciplinary composition will provide benefit to their team’s performance.Cockrell School of Engineerin

Sequential Data Mining using Correlation Matrix Memory

This paper proposes a method for sequential data mining using correlation matrix memory. Here, we use the concept of the Logical Match to mine the indices of the sequential pattern. We demonstrate the uniqueness of the method with both the artificial and the real datum taken from the NCBI databank

Planar Electrode Quadrupole Ion Traps

We present a linear type ion trap consisting of metal lines that are lithographically patterned onto two ceramic substrates. Trapping fields are realized by applying specific voltage potentials to each line. This arrangement allows miniaturization approaches that are immune to surface roughness issues and increased complexities of precision machining of electrode surfaces. We also present how these traps allow a thorough study of higher order multipoles and their effect on mass analyzer performance

The Planar Electrode Linear Ion Trap

We present a linear type ion trap consisting of metal lines that are lithographically patterned onto two ceramic substrates. Trapping fields are realized by applying specific voltage potentials to each line. This arrangement allows miniaturization approaches that are immune to surface roughness issues and increased complexities of precision machining of electrode surfaces. We also present how these traps allow a thorough study of higher order multipoles and their effect on mass analyzer performance

Vascular Dysfunction and Posttraumatic Stress Disorder: Examining the Role of Oxidative Stress and Sympathetic Activity

Purpose: The physiological manifestations of posttraumatic stress disorder (PTSD) have been associated with an increase in risk of cardiovascular disease (CVD) independent of negative lifestyle factors. The goal of the study was to better elucidate the mechanisms behind the increased CVD risk by examining peripheral vascular function, a precursor to CVD. Moreover, this study sought to determine the role of oxidative stress and sympathetic nervous system (SNS) activity in PTSD-induced vascular dysfunction. Methods: Sixteen individuals with PTSD (10 women, 6 men; age 24 ± 4 years), and twenty-four healthy controls (CTRL; 15 women, 9 men, 24 ± 4 years), participated in the study. The PTSD group participated in two visits, consuming either a placebo or antioxidant cocktail (AO - vitamins C and E and alpha lipoic acid) prior to their visits, in a randomized order. Arm vascular function was assessed via the reactive hyperemia- induced flow mediated dilation of the brachial artery (BAFMD) technique and evaluated with Doppler ultrasonography. Brachial artery and arm microvascular function were determined by percent change of diameter from baseline normalized for BA shear rate (BAD/Shear), and blood flow area under the curve (BF AUC), respectively. Heart rate variability (HRV) was used to assess autonomic nervous system activity. Results: BF AUC was significantly lower (p = 0.02) and SNS activity was significantly higher (p = 0.02) in the PTSD group when compared to the CTRL group. BAD/Shear was not different between groups. Following the acute AO supplementation, BF AUC was augmented to which it was no longer significantly different (p = 0.16) when compared to the CTRL group. SNS activity within the PTSD group was significantly reduced (p=.007) following the AO supplementation when compared to the PL condition, and the difference between PTSD and CTRL was no longer significant (p=.41). Conclusion: Young individuals with PTSD demonstrated lower arm microvascular, but not brachial artery, function as well as higher sympathetic activity when compared to healthy controls matched for age, sex, and physical activity level. Furthermore, this microvascular dysfunction and SNS activity was attenuated by an acute AO supplementation to the level of the healthy controls. Taken together, this study revealed that the modulation of oxidative stress, via an acute AO supplementation, improved vascular dysfunction in individuals with PTSD, potentially by reducing the substantial SNS activity associated with this disorder.https://scholarscompass.vcu.edu/gradposters/1084/thumbnail.jp

The social life of books: from a librarian to Walter Benjamin’s Unpacking My Library

In this short essay, the author uses Walter Benjamin's 'Unpacking My Library' to explore the social life of library books. The author examines how numerous actors will come into contact with the book(s) across their social journey into the present and how the librarian is required to make judgments on their supposed 'use value' in any particular setting. Simultaneously, the author considers the process of commodification and de-commodification of library books and how it often falls upon the librarian to determine whether a book will retain its de-commodified status or whether it is no longer needed in that particular setting and will be regressed to the status of a commodity. But while books may be withdrawn from library stock, does that mean that the moments of history embedded within them and their unique identities are lost for history? The author argues not