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Evolving Reproductive Isolation In The Parasitic Wasp Genus Cotesia, Justin P. Bredlau

Theses and Dissertations

Parasitic wasps are highly diverse and play a major role in suppression of herbivorous pest populations, but relatively little is known of the mechanisms driving their diversity. Molecular studies indicate that cryptic species complexes resulting from adaptations to specific hosts or host-foodplants may be common. The gregarious endoparasitoid, Cotesia congregata (Braconidae), is a model system for understanding parasitic wasp biology. It is reported to attack at least 15 species of sphingid caterpillars, most of which are plant family specialists. Molecular studies have demonstrated genetic differentiation of two host-foodplant complex sources originating from Manduca sexta on tobacco (MsT) and Ceratomia catalpae …

Metabolic Engineering Of Serratia Marcescens, Qiang Yan

Theses and Dissertations

The potential value of the chitin biomass (e.g. food waste) is recently considered being ignored by landfill. Chitin can be a potential cheap carbon source for converting into value-added chemicals by microorganisms. Serratia marcescens is a chitinolytic bacterium that harbors endogenous chitinase systems. With goals of characterzing S. marcescens chitinolytic capabilities and applying S. marcescens to chemical production from chitin, my dissertation main content includes five chapters: 1) Chapter 1 highlights background information of chitin source, S. marcescens and potential metabolic engineering targets using chitin as a substrate; 2) Chapter 2 demonstrates that ChiR is a key regulator in regulating …

Mechanisms Regulating Axon Initial Segment Stability, Savannah D. Benusa

Theses and Dissertations

Axon initial segment (AIS) disruption has been described in a number of pathological environments where neuroinflammation is a contributing factor; however, whether this disruption is reversible in unknown. To address the principle of AIS structural recovery, we employed an acute neuroinflammatory model. Acute neuroinflammation induced disruption of AIS structural and functional domains and, importantly, upon resolution of neuroinflammatory conditions, was reversed.

Consistent with other studies, we observed a close interaction of microglia with AISs, and utilized this acute neuroinflammatory model to investigate the relationship between reactive microglia and AIS integrity. Gene expression analysis of microglial transcription profiles identified reactive oxygen …

Natural And Anthropogenic Drivers Of Tree Evolutionary Dynamics, Brandon M. Lind

Theses and Dissertations

Species of trees inhabit diverse and heterogeneous environments, and often play important ecological roles in such communities. As a result of their vast ecological breadth, trees have become adapted to various environmental pressures. In this dissertation I examine various environmental factors that drive evolutionary dynamics in threePinusspecies in California and Nevada, USA. In chapter two, I assess the role of management influence of thinning, fire, and their interaction on fine-scale gene flow within fire-suppressed populations of Pinus lambertiana, a historically dominant and ecologically important member of mixed-conifer forests of the Sierra Nevada, California. Here, I find evidence …

Directing Mesenchymal Stem Cells For Periodontal Regeneration, Charles Stoianovici

Theses and Dissertations

Background: Directing autogenous Mesenchymal Stem Cell (MSC) to defect sites has a great promise in bone regeneration. We designed a MSC specific, bone affinity peptide (E7HA7) by conjugating E7 with a polyglutamate hydroxyapatite (HA) binding motif. We sought to characterize the in-vivo releasing pattern and bioactivity of E7HA7. Methods: HA discs were coated with fluorescent labeled peptides E7HA7, E7HA2 or E7 were subcutaneously implanted in Sprague Dawley rats. In an ectopic bone formation model was used to test the in-vivo bioactivity of E7HA7 conjugated to DBM. Results: E7HA7 showed slower peptide release from scaffolds in comparison to other groups, being …

Processing Of 3′-Blocked Dna Double-Strand Breaks By Tyrosyl-Dna Phosphodiesterase 1, Artemis And Polynucleotide Kinase/ Phosphatase, Ajinkya S. Kawale

Theses and Dissertations

DNA double-strand breaks (DSBs) containing unligatable termini are potent cytotoxic lesions leading to growth arrest or cell death. The Artemis nuclease and tyrosyl-DNA phosphodiesterase (TDP1) are each capable of resolving protruding 3′-phosphoglycolate (PG) termini of DNA double-strand breaks (DSBs). Consequently, a knockout of Artemis and a knockout/knockdown of TDP1 rendered cells sensitive to the radiomimetic agent neocarzinostatin (NCS), which induces 3′-PG-terminated DSBs. Unexpectedly, however, a knockdown or knockout of TDP1 in Artemis-null cells did not confer any greater sensitivity than either deficiency alone, indicating a strict epistasis between TDP1 and Artemis. Moreover, a deficiency in Artemis, but not TDP1, resulted …

Patterns Of Molecular Population Genetic And Phenotypic Variation Associated With Urbanization In The Western Black Widow Spider, Lindsay Miles

Theses and Dissertations

In urban population genetic studies, the "urban fragmentation model" predicts that urbanization acts as a barrier that isolates native populations, and can lead to reduced gene flow and increased genetic drift between populations. The “urban facilitation model” predicts urban areas act as corridors to increase dispersal among urban areas, and can lead to higher genetic diversity within and lower differentiation between urban areas.

In a review of the current literature, we found that there is no consistent signature of reduced within-population genetic diversity or increased between-population genetic differentiation. Analyses that investigate the urban barriers to gene flow also found no …

Chromodomain Helicase Dna Binding Protein 1 (Chd1) Is Required For Orofacial Development In Xenopus, Brent Wyatt

Theses and Dissertations

Abnormalities affecting orofacial development are some of the most common, expensive, and devastating birth defects. Children born with such defects may experience difficulties with eating, breathing, and speech and in addition, these defects often require multiple surgeries to correct them. Therefore, it is critical to understand how the orofacial region develops in order to better treat and prevent these types of birth defects. Xenopus laevis has emerged as a strong model in which to examine orofacial development and was utilized here to investigate the cellular and molecular mechanisms underlying the complex development of the orofacial region. Retinoic acid is one …

Oncogene Induced Dna Replication In Lung Injury Repair And Carcinogenesis, Shilpa Singh

Theses and Dissertations

Deregulation of genome duplication is a common theme in cancer cells. Although multitude of pathways has been discovered and implicated in the ability of oncogenes or loss of function tumor suppressors to induce oncogenesis, most of the pathways ultimately converge in deregulated genome duplication or uncoupling of DNA replication and segregation in cancer cells. It is important to determine how known oncogenes deregulate genome duplication, and if prevention of deregulated genome duplication could be a feasible target to thwart uncontrolled proliferation of cancer cells. Conventional paradigm ascribes the cell proliferative function of the human oncoprotein mouse double minute2 (MDM2) primarily …

Observations Of Trends And Successes Of Revascularization Therapy At Virginia Commonwealth University: A Retrospective Study, Richard W. Sedwick

Theses and Dissertations

The aim of this study was to determine the trends in protocol, success rates, and consistency in follow up of revascularization procedures in a controlled environment. Patients of the Virginia Commonwealth University School of Dentistry were identified who were offered revascularization therapy as a treatment option on immature permanent teeth from January 1, 2010 to May 31, 2017. A total of 77 patients and 78 teeth were evaluated for revascularization therapy. For patients accepting treatment, records were reviewed for outcome assessment and consistency of follow up. A total of 30 patients (31 teeth) were treated following revascularization protocols, with only …

The Effects Of Amixicile On Sub-Gingival Biofilm Cultured From Humans, Kian Azarnoush

Theses and Dissertations

Periodontitis is an inflammatory disease of the oral cavity induced by anaerobic bacteria, that remains to be the primary cause of tooth loss in adults worldwide. Finding an anti-microbial therapeutic to selectively target periodontal pathogens has proven to be difficult, and current treatment modalities only provide a transient benefit. Amixicile is a non-toxic, readily bioavailable novel antimicrobial that targets strict anaerobes through inhibition of the activity of Pyruvate Ferredoxin Oxidoreductase (PFOR), a major enzyme mediating oxidative decarboxylation of pyruvate, a critical step in metabolism. Our study aimed to evaluate the efficacy of amixicile in inhibiting the growth of bacteria harvested …

The Contribution Of Sarm1 To Axonal Degeneration In Cns Inflammatory Disorders, Daniel C. Njoku

Theses and Dissertations

BACKGROUND: Multiple sclerosis (MS) is an inflammatory disease of the central nervous system (CNS) that results in demyelination and axonal loss. Efficiently targeting mechanisms of axonal degeneration in MS has the potential to reduce disability but remains an unmet need. Prior research has identified the protein sterile alpha and TIR motif containing 1 (SARM1) as a critical factor that promotes axonal destruction in the program of axonal degeneration known as Wallerian degeneration. SARM1 inactivation reduces axonal degeneration in a variety of contexts including traumatic and toxic injury, but it remains unknown to what extent SARM1 is involved in axonal degeneration …

The Cognitive And Functional Impact Of Open Heart Surgery: A Pilot Study Including Three Common Procedures (Coronary Artery Bypass Graft, Heart Valve Replacement, And Left Ventricular Assist Device), Robert Fix

Theses and Dissertations

This study investigated the impact of open heart surgery (Coronary Artery Bypass Graft, Heart Valve Replacement, or Left Ventricular Assist Device placement) on cognition, functional performance, and mood in the three months following surgery. The Montreal Cognitive Assessment (MoCA), Kettle Test (KT), Physical Self Maintenance Scale (PSMS), and Hospital Anxiety and Depression Scale (HD) measured global cognition, functional cognition, functional performance, and mood states, respectively.

Thirteen male participants (ages 38 – 75) completed assessments at four time points -- when they were scheduled for surgery, within one week prior to surgery, before hospital discharge after surgery, and three months after …

Experimental Evaluation Of Uranyl Transport Into Mesoporous Silica Gel Using Fluorescence, Brandon M. Dodd

Theses and Dissertations

This research investigated parameters that can affect the use of nanoporous silica gel as a media for accumulating a detectable amount of uranium. The unique fluorescence of the Uranyl (UO₂²⁺) ion was used to evaluate the transport kinetics and accumulation within silica gel in a static fluid and under pressure driven flow. The addition of fluid flow decreased the time constant from on the order of an hour to approximately 2s with a very low fluid velocity of 0.36cm/s. The 0.36cm/s fluid velocity was found to be the critical velocity above which there was no gain in …

Potential Antimicrobial Methods For Provisionalizing Teeth After Endodontic Treatment, Laura T. Garden

Theses and Dissertations

POTENTIAL ANTIMICROBIAL METHODS FOR PROVISIONALIZING TEETH AFTER ENDODONTIC TREATMENT

By Laura T. Garden, DDS

A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in Dentistry at Virginia Commonwealth University.

Virginia Commonwealth University, 2018

Thesis Advisor: Garry Myers, DDS

Department of Endodontics

Objective:To evaluate the effectiveness of a Chlorhexidine soaked cotton pellet on bacterial leakage.

Methods: Fifty-one extracted teeth, including six controls, were instrumented, obturated, and sealed with either a cotton pellet (CP), 2% Chlorhexidine soaked cotton pellet (CHX), or a Permaflo orifice barrier (OB). Each root was suspended between two chambers: the …

Predictors Of Resilient Outcomes Among Juvenile Offenders, Kristina A. Mcguire

Theses and Dissertations

Research on resilience has almost completely bypassed the juvenile justice literature. Using data on 1,354 youth from the Pathways to Desistance study, the present study examined associations between individual, community, and familial risk and promotive factors and resilient outcomes, specifically gainful activity, in juvenile offenders. Results of both logistic and hierarchical regression models indicated significant associations between resilient outcomes in each domain: specifically individual (age at first arrest, motivation to succeed), community (geographic location, exposure to violence), and family (socioeconomic status, parental monitoring) predictors. Finally, this paper discusses reasons for non-significant findings and directions for future research on resilience among …

Acting Mindfully, Dawn Souza

Theses and Dissertations

Acting Mindfully, is a form of embodiment pedagogy that investigates the ways in which actors can explore their craft through a lens that connects them closer to their mind, body, and voice. The document draws content from a wide variety of theatrical movement and vocal practitioners in combination with mindfulness techniques including yoga, meditation, and energy work. Embodiment pedagogy allows the acting student to approach and perform scenes and monologues with truth and authenticity; while allowing them the ability to tell their own stories.

In order to explore this work, a course, Acting and Mindfulness, was introduced at Virginia …

Ageism Among Healthcare Professionals: The Influence Of Personal Aging Anxiety, Job Role, And Work Setting On Attitudes Toward Older Patients, Jennifer L. K. Inker

Theses and Dissertations

Older adults make up a significant and increasing proportion of the U.S. population and are frequent users of healthcare services. Ageism in healthcare, driven by an incomplete and narrowly biomedical perspective on aging, has been linked to various problematic outcomes for older patients, including under- and over-treatment. The purpose of this study was to use the theory of relational ageism to explore the relationship between personal aging anxiety among healthcare professionals and their attitudes to older patients, considering the potentially moderating factors of job role and work setting. Using convenience sampling, clinical healthcare professionals working for a mid-sized, regional healthcare …

Mechanical And Material Characterization Of Advanced Materials For Tissue Regeneration, Bailey Kylara Ricketts Jackson

Theses and Dissertations

In natural disasters and military deployment operations, injury to long bone can cause extensive damage and be difficult to treat and heal quickly. Explosive devices and trauma often produce long-bone (>2-cm length) wounds that are more complicated than common fractures. Due to the size and complexity of these injuries, they can be difficult to treat in a battlefield environment and take a long time to heal completely and properly. Even after the long healing period, these injuries often require rehabilitation to strengthen the muscles that have weakened in the wounded limb. For military applications especially, these effects can put …

Prevention Strategies To Reduce Multifactorial Risk Factors Associated With The Onset Of Coronary Artery Disease: A Systematic Review, Jacqueline A. Burnes

Theses and Dissertations

Noncommunicable diseases such as coronary artery disease continue to remain the principal cause of mortality in the United States, claiming nearly 800,000 lives in 2016. Reducing the onset of chronic diseases, specifically coronary artery disease, requires a fundamental approach to health care, involving patient access to high-quality primary care and accessibility to disease prevention programs. This study examined multifactorial risk factors and prevention mechanisms associated with coronary artery disease.

The applied dissertation is a systematic review of the literature designed to answer the question: What prevention strategies reduce multifactorial risk factors associated with the onset of coronary artery disease? The …

The Effects Of An Afrocentric Curriculum On Reading Scores Of African American Third, Fourth, And Fifth Graders, Trisha J. Baker

Theses and Dissertations

The purpose of this applied research study was to determine the extent to which reading scores on the Diagnostic Reading Assessment (DRA-2) and Measures of Academic Progress (MAP) were impacted across the school years for students enrolled in Afrocentric curriculum (ACC) and non-ACC classrooms, excluding students enrolled in the two-way immersion classrooms, controlling for the test scores from the previous school year, during the 2012-2013, 2013-2014, 2014-2015, and 2015-2016 school years.

The research study followed a correlational research design to determine whether the size of the two reading-assessment scores varied across school years in efforts to determine whether the ACC …

Fabrication And Application Of Functional Polymer-Protein Coreshell Nanoparticles, Lin Lu

Theses and Dissertations

The study of polymer-protein nanoparticles is of increasing interest due to their various potential applications in biosensing, imaging, bioseparations, gene and drug delivery, etc. Synthetic polymers can be tailored with different functional groups and properties, therefore, they can serve as platforms to impart proteins with additional features and assist proteins to better perform biological functions. In this dissertation work, we were mainly focusing on the preparation of polymer-protein core-shell nanoparticles by synthesizing new functional polymers and assembling them with proteins for different applications. In chapter 1, a pyridine grafted diblock copolymer P(CL-g-Py)-b-PCL was prepared through ROP and CuAAC reactions. …

Role Of Mir-489 In Her2 Positive Breast Cancer, Yogin Patel

Theses and Dissertations

Human epidermal growth factor receptor 2 (HER2 or ErBb2) is a receptor tyrosine kinase overexpressed in 20-30% of breast cancers and associated with poor prognosis and outcome. Dysregulation of several micro RNAs (miRs) plays a key role in breast cancer progression and metastasis. In this study, we screened and identified miRs dysregulated in HER2-positive breast cancer cells. Molecular study demonstrated that miR-489 was specifically downregulated by the HER2-downstream signaling, especially the MAPK pathway. Restoration or overexpression of miR-489 in HER2-positive breast cancer cells significantly inhibited cell growth in vitro and decreased the tumorigenicity and tumor growth in xenograft mice. Mechanistically, …

Mechanisms Of Rad51d-Dependent Repair Of Dna And Telomere Damage Induced By Interstrand Crosslinking Agents And Thiopurines, Nicole M. Reilly

Theses and Dissertations

Mutations in homologous recombination (HR) genes increase genomic instability, an enabling characteristic of cancer. However, the status of these same genes can also determine chemotherapy outcomes. RAD51D is a breast and ovarian cancer susceptibility gene that is an important component of HR. Mammalian cells defective for RAD51D have extensive chromosomal aberrations and are more sensitive to the interstrand crosslink-inducing agent mitomycin C (MMC) and the thiopurine 6-thioguanine (6TG). Previously, the RNF138 E3 ubiquitin ligase was identified to promote RAD51D ubiquitination, and loss of RNF138 also increased cellular sensitivity to MMC. Ubiquitination assays were used to show that a 3-ubiquitin modification …

What Makes Killing For Organs Wrong? A Philosophical Defense Of The ‘Dead Donor’ Rule, Adam Omelianchuk

Theses and Dissertations

The purpose of my dissertation is to give a philosophic defense of the so-called “dead donor” rule (DDR) in transplant ethics, something that is sorely lacking in the current literature on the topic. Part of my project is concerned with the rule’s correct formulation: What exactly does it forbid? I answer that it is primarily concerned with prohibiting the killing of the donor for his or her organs, and that it need not be concerned with requiring that the donor be dead before surgery begins (as important as that might be). What is morally important is that surgery not be …

The Effects Of A Gamified Curriculum On High-School Students, Joshua Kyle Bastean

Theses and Dissertations

One of the emerging trends in education is gamification, a concept that has been applied in other fields, such as business and advertising, with great success. Gamification can be defined as adding game elements to non-game constructs. This study followed a high-school Algebra II teacher and 10 of her students in an attempt to document the effects of gamification on student academic engagement. Multiple methods of data collection were used to gather data from students and teachers. After analysis, the data showed that gamification had a positive effect on student academic engagement. The results were used to create an action …

The Impact Of A Peer-Teaching Instructional Approach On A Student’S Self-Confidence, John Corral

Theses and Dissertations

This study examines a problem of practice stemming from students not given the same opportunities to use and develop self-confidence and take on higher levels of responsibility in the classroom as they prepare for the 21st century workforce in our society. Recognizing a problem of practice evident in our high school with low-selfesteem in students, this paper studies the effects of implementing a peer-teaching instructional approach to help develop students’ self-confidence and emerging leadership skills (Lockie & Van Lanen, 2008). The central research question addressed in this study is: what is the impact of implementing a peer-teaching instructional approach on …

Phylogeny, Ancestral Genome, And Disease Diagnoses Models Constructions Using Biological Data, Bing Feng

Theses and Dissertations

Studies of bioinformatics develop methods and software tools to analyze the biological data and provide insight of the mechanisms of biological process. Machine learning techniques have been widely used by researchers for disease prediction, disease diagnosis, and bio-marker identification. Using machine-learning algorithms to diagnose diseases has a couple of advantages. Besides solely relying on the doctors’ experiences and stereotyped formulas, researchers could use learning algorithms to analyze sophisticated, high-dimensional and multimodal biomedical data, and construct prediction/classification models to make decisions even when some information was incomplete, unknown, or contradictory. In this study, first of all, we built an automated computational …

Complete Measurement System For Measuring High Voltage And Electrical Field Using Slab-Coupled Optical Fiber Sensors, Nikola Stan

Theses and Dissertations

A slab-coupled optical fiber sensor (SCOS) falls into a narrow class of all-dielectric optical fiber electric field sensors, which makes it a perfect candidate for measurements of high electric fields in environments where presence of conductors is highly perturbing to the system under test. Its nonlinear response to high fields requires a new nonlinear calibration technique. A nonlinear calibration method is explained and demonstrated to successfully measure high electric fields, as well as high voltages with dynamic range up to 50 dB. Furthermore, a SCOS can be fitted into narrow spaces and make highly localized measurements due to its small …

Investigating The Role Of Nicotinic Acetylcholine Receptor Agonists In Lung Cancer Progression And Chemosensitivity In The Context Of Treating Chemotherapy-Induced Peripheral Neuropathy, Sarah L. Kyte

Theses and Dissertations

While cancer chemotherapy continues to significantly contribute to the number of cancer survivors, exposure to these drugs can often result in chemotherapy-induced peripheral neuropathy (CIPN), a consequence of peripheral nerve fiber dysfunction or degeneration. CIPN is characterized by sensory symptoms in the hands and feet, such as numbness, burning, and allodynia, resulting in an overall decrease in quality of life. Paclitaxel (Taxol), a microtubule poison that is commonly used to treat breast, lung, and ovarian cancers, has been found to cause CIPN in 59-78% of cancer patients. There is currently no effective preventative or therapeutic treatment for this side effect, …