Digital Commons Network^™

Assessing The Relative Influences Of Abiotic And Biotic Factors On A Species’ Distribution Using Pseudo-Absence And Functional Trait Data: A Case Study With The American Eel (Anguilla Rostrata), Taylor E. Woods

Theses and Dissertations

Species’ distributions are influenced by abiotic and biotic factors but direct comparison of their relative importance is difficult, particularly when working with complex, multi-species datasets. Here, we present a flexible method to compare abiotic and biotic influences at common scales. First, data representing abiotic and biotic factors are collected using a combination of geographic information system, remotely sensed, and species’ functional trait data. Next, the relative influences of each predictor variable on the occurrence of a focal species are compared. Specifically, ‘sample’ data from sites of known occurrence are compared with ‘background’ data (i.e. pseudo-absence data collected at sites where …

Orientia Tsutsugamushi Modulates Endoplasmic Reticulum Stress To Benefit Its Intracellular Growth And Targets Nlrc5 To Inhibit Major Histocompatibility Complex I Expression, Kyle G. Rodino

Theses and Dissertations

Scrub typhus, caused by the obligate intracellular bacterium Orientia tsutsugamushi, afflicts one million people annually. Despite being a global health threat, little is known about O. tsutsugamushi pathogenesis. Here, we demonstrate that O. tsutsugamushi modulates the ER and ER-associated processes as mechanisms of nutritional virulence and immune evasion. To obtain amino acids to fuel replication, O. tsutsugamushi simultaneously induces ER stress and the unfolded protein response (UPR) while inhibiting ER-associated degradation (ERAD) during early infection time points. During exponential growth, the bacterium releases the ER bottleneck, resulting in generation of ERAD-derived amino acids that it parasitized for replication. …

Glycosaminoglycan Lyases In The Preparation Of Oligosaccharides, Alhumaidi B. Alabbas

Theses and Dissertations

Glycosaminoglycans are heterogeneous polysaccharides that mediate important biological functions. There has been considerable interest in deciphering the precise GAG sequences that are responsible for protein interactions. In fact, several GAG oligosaccharides have been discovered to date as targeting proteins with higher level of specificity. Yet, it has been difficult to develop GAG oligosaccharides as drugs. One of the key reasons for this state of art is that GAG synthesis is extremely challenging and is highly structure-specific. Thus, much of the biology and pharmacology of GAG remains unknown and unexploited to date.

An alternative approach is to prepare GAG oligosaccharides using …

Counterregulatory Effects Of Ptx3 On Inflammation And Cellular Aging, Aaron L. Slusher

Theses and Dissertations

Pentraxin 3 (PTX3) is a vital regulator of innate immune function that has been shown to counterregulate pro-inflammatory signaling and protect against the development of cardiovascular disease (CVD). Less is known about how PTX3 may mitigate against CVD risk by regulating the pro-inflammatory response at the cellular level. Therefore, this dissertation details four manuscripts which aimed to examine the capacity of PTX3 to regulate the innate immune response of peripheral blood mononuclear cells (PBMCs) isolated from healthy adults. Manuscript 1 examined the capacity of PTX3 to alter the inflammatory milieu following in vitro stimulation of isolated PBMCs with the pro-inflammatory …

Gastrointestinal Microbiota Modulate Antinociceptive Tolerance Development In Mice With Chronic Morphine Exposure, Ryan A. Mischel

Theses and Dissertations

In October 2017, the United States government declared a state of public health emergency in response to the burgeoning prescription opioid epidemic. Opioid analgesics are the gold standard of therapy for moderate to severe pain, but their clinical utility is greatly limited by analgesic tolerance – a primary driver of diminished pain control and opioid dose escalations. Integral in this process are primary afferent sensory neurons in dorsal root ganglia (DRG), the first-order components of nociceptive sensation. With surmounting evidence that morphine and other narcotics can alter gut microbial composition and promote bacterial translocation to other tissues, a question arises …

The Periodontal Specialty: A Survey Regarding Our Future, John H. White

Theses and Dissertations

Purpose: To determine the characteristics influencing periodontal practices in Virginia and report on the anticipated changes in practice.

Methods: A REDCap survey was emailed to Virginia based American Academy of Periodontology (AAP) members assessing personal and practice demographics, trends in dental treatment and practice models, and how periodontists will adjust to account for these trends.

Results: The response rate was 31% (n=46). Respondents report greater referrals from more experienced general practitioners (GPs). Student debt was associated with age. Respondents ranked biologic advances, treatment of peri-implantitis, digital dentistry, development of corporate and group practice models, and GPs incorporating more periodontal …

Investigating The Presence And Correlates Of Anti-Thin Bias In Adults, Alexandria Davies

Theses and Dissertations

Weight stigma is associated with negative health outcomes across the BMI continuum. However, few studies have examined weight discrimination targeting people with low body weights. This investigation explored the presence of anti-thin bias, defined as the belief that people with low BMIs have undesirable personality characteristics. Participants were randomly assigned to read one of six vignettes about women that differed by race (White and Black) and weight status (slightly underweight, normal weight, and slightly overweight). Negative personality characteristics were more likely to be ascribed to both underweight and overweight women, compared with normal weight women. Furthermore, participants were significantly more …

Strengthening Social Networks Of Youth Aging Out Of Foster Care: Promoting Positive Adult Outcomes, Rachel D. Rosenberg

Theses and Dissertations

During the transition to adulthood, youth often rely on the people in their life for support. However, for transition-aged foster youth, these supports may not be available or may look different than supports available to youth in the general population. Relationships with supportive adults have been found to help former foster youth transition to adulthood, but little is known about the adults youth have in their network. Foster youth who report increased levels of social capital have been shown to experience higher levels of success in young adulthood. However, as former foster youth transition to adulthood, a lack of in-depth …

Prevalence And Factors Of Sibling-Recurrent Dental Treatment Under General Anesthesia, Brandy N. Edmonds

Theses and Dissertations

Objective/Aims: Assess the prevalence of sibling recurrent dental general anesthesia (DGA) at VCU Pediatric Dentistry. Assess factors that contribute to sibling recurrent dental general anesthesia. Methods: The guardian of patients with siblings were provided a questionnaire to assess the prevalence and factors associated with recurrent DGA. Results: A total of 40 families with a child presenting for GA and at least one sibling were included in the study. Of these, 45% had sibling-recurrent GA treatment (20% in one sibling; 25% in 2 or more siblings). Additionally, 13% of the children currently presenting for GA had already been treated under GA, …

Assessing Feasibility And Effectiveness Of Pediatric Dental Provider’S Role In Oral Health And Prevention Education In The Care Of Children With Leukemia, Hannah Rustin

Theses and Dissertations

Purpose: Pediatric dentists could serve a role in care of children with leukemia. Oral sequelae of cancer therapies are well documented. The purpose of this study is to assess the feasibility and effectiveness of the pediatric dentist in the care of patients with leukemia. Methods: Pediatric Hematology and Oncology at Virginia Commonwealth University was educated on the proposed protocol and administered a questionnaire to assess feasibility of implementing prevention education by the pediatric dentist. Patients were randomized into two groups at diagnosis: one receiving current oral health protocol and those receiving one-on-one prevention education with the pediatric dentist at three …

Using The Frog Epidermis To Uncover Desmosome Function And Regulation In The Developing Embryo, Navaneetha Krishnan Bharathan

Theses and Dissertations

The desmosome is one of the major cell adhesion junctions found in the epithelia, heart, and hair follicle. Described as a “rivet” that hold cells together, it provides these tissues with the integrity to withstand the tremendous forces they face in everyday life. Defects in this junction can lead to devastating diseases where patients are susceptible to skin infections and cardiovascular defects. Limited treatments exist for diseases of the desmosome, and strategies do not target all symptoms. Therefore, delineating the function and regulation of desmosomes is of paramount importance for the development of prevention and treatment strategies. The Xenopus laevis …

Anxiety In Menopause: A Qualitative Inquiry, Eleanor Bremer

Theses and Dissertations

Background: Anxiety is one of the mood symptoms experienced by menopausal women; however, anxiety symptoms during menopause have received little attention in the literature despite the potential impact on quality of life. Many of the tools used to evaluate and measure anxiety associated with menopause assume that menopausal anxiety shares similar criteria as anxiety disorders and this may not be entirely true. There are very few studies that have assessed anxiety in the context of menopause leaving the concept of menopausal anxiety not well defined and raising the question: Is menopausal anxiety a unique and distinctly different syndrome? The purpose …

Metabotropic Glutamate Receptor 2 Activation: Computational Predictions And Experimental Validation, Amr Ellaithy

Theses and Dissertations

G protein-coupled receptors (GPCRs) are the largest family of signaling proteins in animals and represent the largest family of druggable targets in the human genome. Therefore, it is of no surprise that the molecular mechanisms of GPCR activation and signal transduction have attracted close attention for the past few decades. Several stabilizing interactions within the GPCR transmembrane (TM) domain helices regulate receptor activation. An example is a salt bridge between 2 highly conserved amino acids at the bottom of TM3 and TM6 that has been characterized for a large number of GPCRs. Through structural modeling and molecular dynamics (MD) simulations, …

The Influence Of Clinically Meaningful Factors On The Performance Of The Recommended Annual Diabetic Foot Screening, Trisha A. Sando

Theses and Dissertations

Background: Diabetic foot ulcers are the result of multiple complications from hyperglycemia and lead to poor quality of life and high healthcare costs. The annual diabetes foot screening exam (ADFSE) and prevention interventions can reduce DFUs up to 75%. In 2015, 71% of the US population received the ADFSE.

Objectives: The main objectives of this dissertation were: 1) to determine the association between adherence to diabetes self-management behaviors and the ADFSE, 2) to determine the association between concordant and discordant comorbidities and the ADFSE and 3) to determine the association between the performance of diabetes preventive care processes, number of …

Queer Health Equity And Cervical Cancer: Identifying Social Determinants Of Papanicolaou Test Uptake In A Sample Of Sexual Minority Women And Gender Nonbinary Individuals, Ariella R. Tabaac

Theses and Dissertations

Sexual minority women (SMW) demonstrate lower rates of cervical cancer screening than heterosexual women. This is concerning as lesbian and bisexual women tend to engage in higher rates of substance-related cancer risk behaviors, unprotected sex, and tend to have higher body mass indices, all of which are risk factors for cancer development. Another major risk factor, screening avoidance, places SMW at increased risk for the development of high grade cervical lesions in the absence of early detection practices, which is likely to impact overall cervical cancer morbidity in this population. The aim of the present study was to utilize the …

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 …

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 …

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 …

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 …

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 …

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 …

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 …

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 …

Targeting Bcl-2 Family Members In The Cell Death Pathway To Treat Head And Neck Cancer, Erin L. Britt

Theses and Dissertations

Head and neck cancer accounts for approximately 3 percent of all cancers in the United States, and over 90% of them are head and neck squamous cell carcinoma (HNSCC). Chemotherapeutic drugs that treat HNSCC can activate BCL-2 family dependent apoptosis. Pro-apoptotic NOXA induced by adenovirus (Ad-NOXA) or fenretinide inactivates anti-apoptotic MCL-1, while ABT-263 can inactivate other anti-apoptotic BCL-2 family members such as BCL-2 and BCL-X_L. We used p53 inactive HN8 and HN12, p53 wild-type UMSCC1, and HPV-positive UMSCC47 human HNSCC cell lines and five mouse HNSCC cell lines. Cells were treated with Ad-NOXA, ABT-263, and fenretinide alone or …

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 …

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 …

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 …

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 …

Determining Tidal Characteristics In A Restored Tidal Wetland Using Unmanned Aerial Vehicles And Derived Data, Victor Thornton

Theses and Dissertations

Unmanned aerial vehicle (UAV) technology was used to determine tidal extent in Kimages Creek, a restored tidal wetland located in Charles City County, Virginia. A Sensefly eBee Real-Time Kinematic UAV equipped with the Sensor Optimized for Drone Applications (SODA) camera (20-megapixel RGB sensor) was flown during a single high and low tide event in Summer 2017. Collectively, over 1,300 images were captured and processed using Pix4D. Horizontal and vertical accuracy of models created using ground control points (GCP) ranged from 0.176 m to 0.363 m. The high tide elevation model was subtracted from the low tide using the ArcMap 10.5.1 …

A Laboratory Study Of Stress Reactions To Witnessing A Police Killing Of An Unarmed Black Man: Discrimination, Distress Tolerance, Ethnic Identity, And Risk-Taking, Michael A. Trujillo

Theses and Dissertations

Black individuals have been disproportionately targeted by law enforcement, most notably in shooting deaths at the hands of police, and has contributed to a general distrust of law enforcement. A rise in citizen journalism has helped document excessive use of force by police on video; however, little is known how individuals respond to viewing this type of media. A history of race-based stress is likely to contribute to an expectation of racism and may impact how individuals respond to videos of the treatment of unarmed Black men at the hands of police, with some evidence suggesting ethnic identity may moderate …