Digital Commons Network^™

An Identification Of Tgf-B'S Role In Ischemic Cholangiopathy, Courtney Chmielewski

Theses and Dissertations

Organ transplants are a necessary intervention for many diseases that result in end stage organ failure. The donation pool cannot match the demands of the transplant list, so expanding the pool to include donation after cardiac death (DCD) is desired. However, there are increased odds of graft failure and ischemic cholangiopathy leading to inferior outcomes when DCD livers are used. Ischemic cholangiopathy consists of multiple diffuse strictures and fibrosis of the bile ducts leading to a loss of epithelialization and fibrosis. The cellular mechanism is proposed to be epithelial-to-mesenchymal transition (EMT). TGF-�� is seen as a key initiator of EMT, …

Development Of A Single Use Device Intended To Wash Blood Clot Debris From A Stent Retriever In The Operating Room, Shane Diller

Theses and Dissertations

Ischemic stroke is a life-threatening condition that requires immediate surgical intervention to remove the blood clot that is lodged in the blood vessels of the brain. Mechanical thrombectomy, performed by an endovascular surgeon, involves inserting a stent retriever, which deploys distally and attempts to capture the clot when dragged backwards. A complication prevalent in 50% - 67% of cases is that the blood clot is only partially removed and clings to the mesh framework of the stent. The operating surgeon must either clean the debris from the stent retriever, to be reinserted or throw the stent retriever away and open …

State Economic Development: Analyzing The Moderating Effects Of Business Climate On Economic Growth, Sean A. Brazier

Theses and Dissertations

States across the country focus intensely on creating jobs, catalyzing capital investment, and stimulating economic output. They pursue different strategies, mixing and matching a variety of tactics in the pursuit of their economic objectives. While scholars have studied the relationship between economic development tactics and economic growth or business climate and economic growth, none to my knowledge have studied the impact of economic development efforts on economic outcomes while accounting for a state’s business climate.

I found economic development spending to be negatively associated with employment growth (other measures, real gross state product and per capita income growth, were not …

A Comparison Of Three-Dimensional Printing Technologies On The Precision, Trueness, And Accuracy Of Printed Retainers, Owais A. Naeem

Theses and Dissertations

Purpose: The aim of this study was to evaluate the differences in the precision, trueness, and accuracy of 3D printed orthodontic clear retainers produced using printer systems with various printing technologies.

Methods: Retainers (n=15) were printed using four different 3D printers: a stereolithography (SLA) printer, two different digital light processing (DLP and cDLP) printers, and a polyjet photopolymer (PPP) printer. The 3D printed retainers were transformed into a digital file through a cone-beam computed tomography scan that was compared to the original image using a 3D superimposition analysis software. At previously chosen landmarks (R6, L6, R3, L3, R1, L1) retainers …

Implementation Of A Hierarchical Embedded Cyber-Attack Detection System In Unmanned Aerial Systems, Kevin Yang

Theses and Dissertations

With the development of technology revolving around Unmanned Aerial Systems (UAS), UAS are becoming more widely used across a variety of applications. In every scenario, the system in question needs to have very distinct requirements and specifications, many of which revolve around safety and reliability. As such, these systems need to provide mechanisms in order to handle different attacks by adversaries on the outside. Since these systems have the ability to operate in many different flight modes according to their mission, detection and mitigation of the attacks become increasingly difficult over time. Cyber-attacks and their focuses are often evolving, and …

Non-Destructive, Rapid Differentiation Of Cell Types Relevant To Sexual Assault Investigations Utilizing Morphological And Autofluorescence Signatures, Taylor R. Moldenhauer

Theses and Dissertations

Current methods for confirming the presence of spermatozoa in sexual assault samples can be time-consuming and often lack sensitivity; however, this remains the most definitive test for the presence of semen. Additionally, male DNA can be deposited without the presence of intact sperm as may be the case with seminal fluid from vasectomized individuals or sexual activity where seminal fluid is not recovered (e.g., perpetrator wears a condom, penetration without ejaculation, etc.). The ability to detect bodily fluids, as well as quantify their presence in a sample, could aid in forensic DNA analysis by limiting the amount of time performing …

The Effect Of Time And Temperature On The Quality Of Latent Fingerprints On Incandescent Lightbulbs, Varying Donors Age And Sex, Kinaysha M. Collazo Maldonado

Theses and Dissertations

Fingerprints are used as a means of identification, but there are no established methodologies to determine time since deposition of latent fingerprints by visual means alone. This research considered the influence of age and sex on the quality of recovered latent prints from lit and unlit lightbulbs from 1 to 10 days, using accumulated degree hours (ADH) to account for both heat and time simultaneously. Two male and two female donors (one of each aged <40 and >40 years) were used. A thermal imaging camera was used to monitor the lightbulbs top and middle regions, which were significantly different (p≤0.05) for the …

The Analysis Of Neural Heterogeneity Through Mathematical And Statistical Methods, Kyle Wendling

Theses and Dissertations

Diversity of intrinsic neural attributes and network connections is known to exist in many areas of the brain and is thought to significantly affect neural coding. Recent theoretical and experimental work has argued that in uncoupled networks, coding is most accurate at intermediate levels of heterogeneity. I explore this phenomenon through two distinct approaches: a theoretical mathematical modeling approach and a data-driven statistical modeling approach.

Through the mathematical approach, I examine firing rate heterogeneity in a feedforward network of stochastic neural oscillators utilizing a high-dimensional model. The firing rate heterogeneity stems from two sources: intrinsic (different individual cells) and network …

Teacher Approaches To Women’S History, Gender, And Feminism In Secondary Social Studies, Kimberly R. Bowman

Theses and Dissertations

While several scholars have worked to reimagine social studies curriculum from a feminist perspective, there are few studies that look at how teachers understand and experience gender equity work (Bohan, 2017; Engebretson, 2018). This study seeks to bridge that gap between theory and practice in order to progress toward a more gender-equitable social studies education. Utilizing a hermeneutic circle design to facilitate dialogue across participants, I conducted one-on-one, semi-structured interviews with seven secondary social studies teacher participants and collected participant-provided curriculum materials. Using techniques from constructivist grounded theory, I analyzed how teachers made sense of their experiences trying to include …

Ceramide Synthase 2 Interacts With Ceramide Synthases 5 And 6 At The Mrna And Protein Levels, Dorothy Yen

Theses and Dissertations

Ceramides and sphingolipids make up major portions of the plasma membrane and therefore are crucial for cell proliferation, survival, and death. With dysregulation comes numerous pathophysiological conditions, such as Alzheimer's, Huntington's Disease, Creutzfeldt-Jakob, cardiovascular disease, and many cancers. However, the regulation of the enzymes responsible for catalyzing the formation of ceramides is still not well understood. In this experiment, three isoforms were of focus: CerS2, CerS5, and CerS6. Through mRNA, protein, and immunofluorescence analysis, it can be concluded that these isoforms do indeed interact within the human cell in order to upregulate their activity. It was also found that cells …

Validation Of Ninein As An Ethanol-Related Quantitative Trait Gene: Reassessment, Design, And Functional Validation Of Reference Genes For Qpcr Analysis Of Brain Tissue In Mice, Jessica L. Jurmain

Theses and Dissertations

The increasing use of quantitative real-time polymerase chain reaction (qPCR) as a method for quantifying gene expression has led to an increased demand for standardization of data analysis methods to ensure accurate reporting and robust, reproducible results. The exponential nature of qPCR amplification results in the potential magnification of what are usually very small sources of error. Relative gene expression calculations circumvent this issue by normalizing target gene expression data to within-sample expression of a previously validated, stably expressed reference gene or genes. Multiple studies discussed herein have found that qPCR data are more reliable and reproducible when multiple reference …

Surrogate Memories In Animation And Sound, Jared Duesterhaus

Theses and Dissertations

A document in support of my exploration into memory in relation to the mediums of animation, sound, and theater. A reflection on remembering as a creative act.

Focal Augmentation Of Somatostatin Interneuron Function And Subsequent Circuit Effects In Developmentally Malformed, Epileptogenic Cortex, Nicole Ekanem

Theses and Dissertations

Drug-resistant epilepsy (DRE) is a common clinical sequela of developmental cortical malformations such as polymicrogyria. Unfortunately, much remains unknown about the aberrant GABA-mediated circuit alterations that underlie DRE's onset and persistence in this context. To address this knowledge gap, we utilized the transcranial freeze lesion model in optogenetic mice lines (Somatostatin (SST)-Cre or Parvalbumin (PV)-Cre x floxed channelrhodopsin-2) to dissect features of the SST, PV, and pyramidal neuron microcircuit that are potentially associated with DRE. Investigations took place within developmental microgyria’s known pathological substrate, the adjoined and epileptogenic paramicrogyral region (PMR). As well, microcircuit relationships within the previously unexplored range …

Identifying And Addressing Barriers To Accessing Treatment For Substance Use Disorders Among Opioid-Misusing Individuals Following Implementation Of The Affordable Care Act, Mirinda A. Gormley

Theses and Dissertations

BACKGROUND: This project utilized opioid-misusing adults to investigate the association between type of opioid misuse and perceived readiness, financial, structural, and stigma-related barriers to accessing SUD treatment; identified classes of PSU and the association between patterns of PSU and perceived barriers, and evaluated effectiveness of an out-of-hospital opioid-treatment connection program.

METHODS: Respondents from 2015-2018 NSDUH included insured adults reporting past year opioid misuse. Multivariate logistic regression assessed relationship between type of opioid misuse and perceived barriers to SUD treatment. LCA identified patterns of PSU, and multivariate logistic regression assessed association between PSU classes and perceived barriers. EMS ePCRs for nonfatal …

Come And Get Your Capital, Sis: The Use Of Twitter To Compensate For Gendered And Racialized Job Networks Among Creatives, Sasha A. Pierre- Louis

Theses and Dissertations

Due to racialized and gendered exclusion and discrimination, Black and women jobseekers do not have the same access to social ties in the labor market as white men. A number of Black Twitter users, particularly Black women, have cultivated networks on Twitter and elsewhere as explicit alternatives to this old boys’ network. This study aimed to understand how workers in creative industries—which tend to be more reliant on referrals—use Twitter to expand their social networks and gain access to job opportunities, and how their use of Twitter differed by race and gender. Four hashtags were queried through the Twitter application …

Characterization Of The Gonococcal Calprotectin Zn-Acquisition System, Tdfh, And The Efficacy Of Metal Starvation For Treating Gonococcal Disease, Michael T. Kammerman

Theses and Dissertations

Abstract

Characterization of the Gonococcal Calprotectin Zn-Acquisition System, TdfH, and the Efficacy of Metal Starvation for Treating Gonococcal Disease.

By Michael T. Kammerman, B.S.

A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at Virginia Commonwealth University

Virginia Commonwealth University, 2020

Major Director: Cynthia Nau Cornelissen, Ph.D.

Professor, Department of Microbiology and Immunology

Neisseria gonorrhoeae, the bacterial agent that is responsible for the human disease gonorrhea, has had a steady increase in the number of infections per year. In 2018 the WHO estimated over 87 million infections occurred world-wide, and the CDC …

“Is Therapy For Me?” Perceptions Of Therapy Inclusivity And Willingness To Seek Help Among Black Emerging Adults, Randl B. Dent

Theses and Dissertations

Mental health issues are prevalent among Black emerging adults; however, they tend to underutilize mental healthcare services. The goals of the current study were to examine whether: (1) perceived therapy inclusivity would predict willingness to utilize mental healthcare services and (2) the relationship between perceived therapy inclusivity and willingness would be moderated by two indices of racial identity (i.e., centrality and private regard). Results provide evidence that greater perceptions of therapy inclusivity are associated with greater willingness to seek mental health services even after controlling for factors, such as gender, self-stigma, and previous mental healthcare utilization. Additionally, there was no …

Comparison Of Endodontic Treatment Planning Decisions Using Cone Beam Computed Tomography Versus Periapical Radiography In Previously Endodontically Treated Molars, Sarah Alkanderi

Theses and Dissertations

Objectives: The aim of this study was to determine if treatment plans differ when evaluating previously endodontically treated molars using periapical images (PA’s) alone versus PA’s and CBCT.

Methods: A retrospective cohort chart review was conducted including 67 previously treated molars that had a CBCT taken. Two calibrated board-certified endodontists evaluated standard PA’s. A data sheet questionnaire regarding radiographic findings and treatment plan decisions was completed. Two weeks later, the same steps were repeated but the examiners evaluated both PA’s and CBCT images and again arrived at a recommended treatment plan.

Results: Agreement between raters was assessed with Cohen’s Kappa …

Cyberbullying: School Administrators' Perceptions Of Law And Prevalence, And Their Roles In Prevention, Intervention And Discipline, Suzan Gragg Denby

Theses and Dissertations

This study was aimed at investigating secondary school administrators’ experiences with and their perceptions of cyberbullying, as well as their intervention and prevention procedures. As technology has become ubiquitous in our society, students’ use has increased and impacted the school environment. Given the potential for cyberbullying and the negative effects of such, schools harbor the responsibility to prevent and intervene in such occurrences. This can be a tricky process.

This study included 12 administrators of secondary schools across eight school divisions in Virginia. Through an interview process, administrators spoke of their experiences with technology and cyberbullying incidents, and how they …

A Critical Multiple Case Study Analysis Examining The Implementation Of The Every Student Succeeds Act (Essa) To Promote Positive School Climate, Weade W. James

Theses and Dissertations

This study explored the role of federal policy in improving school climate, and examined how federal policy, specifically the Every Student Succeeds Act (ESSA) is being implemented at the state-level to address school climate issues. A qualitative multiple-case study design with content analysis was used as the leading approach to understanding how states are implementing ESSA’s school climate measure for accountability. ESSA is the nation’s federal education law that was enacted in 2015 and replaced No Child Left Behind (NCLB). I compared states’ implementation of ESSA’s school climate and safety (SCS) measure, including how states are measuring SCS and whether …

Psychometric Developments Of The Ace-Iq: Understanding The Trauma History Of Latine Immigrants, Jorli K. Swingen Dr.

Theses and Dissertations

Adverse childhood experiences (ACEs) have a profound effect on an individual’s physical and mental health. The World Health Organization has recently updated the ACE questionnaire so it could be used with international populations. The Adverse Childhood Experiences-International Questionnaire (ACE-IQ), has not been translated to Spanish or used with Latine immigrants.

This study translated the ACE-IQ into Spanish, evaluated the psychometric properties of the questionnaire, and collected data on 184 four adult English Language Learners in Chesterfield County, VA.

There is evidence of internal consistency for the ACE-IQ as a whole (α = .908) and within subscales. Three factors were identified …

Interspecific Gene Flow Potentiates Adaptive Evolution In A Hybrid Zone Formed Between Pinus Strobiformis And Pinus Flexilis, Mitra Menon

Theses and Dissertations

Species range margins are often characterised by high degrees of habitat fragmentation resulting in low genetic diversity and higher gene flow from populations at the core of the species range. Interspecific gene flow from a closely related species with abutting range margins can increase standing genetic diversity and generate novel allelic combinations thereby alleviating limits to adaptive evolution in range margin populations. Hybridization driven interspecific gene flow has played a key role in the demographic history of several conifer due to their life history characteristics such as weak crossability barriers and long generation times. Nevertheless, demonstrating whether introgression is adaptive …

A Graph Theoretical Approach To The Dollar Game Problem, Rachel Koch

Theses and Dissertations

In this thesis we consider a problem in Graph Theory known as the Dollar Game. The Dollar game was first introduced by Matthew Baker of the Georgia Institute of Technology in 2010. It is a game of solitaire, played on a graph, and is a variation of chip firing, or sand-piling games. Baker approached the problem within the context of Algebraic Geometry. It is the goal of this paper to provide an overview of the necessary graph theory to understand the problem presented in this game, as well as background on chip firing games, their history and evolution. Finally we …

I Hope My Black Skin Don't Dirt This White Tuxedo, Luis A. Vasquez La Roche

Theses and Dissertations

I Hope My Black Skin Don't Dirt This White Tuxedo is a series of works--sculpture, installations, and performances--that explore themes of shame, failure, commodity, ephemerality, ritual, resilience, erasure, race, and death. The research and interest in these themes stem from a page of the Trinidad and Tobago Slave Registry. I use the research that surrounds this document to highlight different moments in history, in my personal life, and to imagine near futures.

On-Demand Electrically Induced Decomposition Of Thin-Film Nitrocellulose Membranes For Wearable Or Implantable Biosensor Systems, Benjamin M. Horstmann

Theses and Dissertations

Implantable or subcutaneous biosensors used for continuous health monitoring have a limited functional lifetime requiring frequent replacement and therefore may be highly discomforting to the patient and become costly. One possible solution to this problem is use of biosensor arrays where each individual reserve sensor can be activated on-demand when the previous one becomes inoperative due to biofouling or enzyme degradation. Each reserve biosensor in the array is housed in an individual Polydimethylsiloxane (PDMS) well and is protected from exposure to bodily fluids such as interstitial fluid ( ISF) by a thin-film nitrocellulose membrane. Controlled activation is achieved by decomposing …

Is Direct Transport To A Level I Trauma Center Associated With Better Outcomes In Patients With Traumatic Brain Injury Compared To Patients That Are Transferred To Trauma Level I From Other Hospitals, Narad Mishra

Theses and Dissertations

Transferring patients with traumatic brain injury (TBI) to trauma level I hospital from other lower level hospitals has been shown to increase the mortality compared to when patients are directly transported to trauma centers. Despite the results from studies and the field triage recommendation of transporting the TBI patients to trauma center, nearly half of the TBI cases are transported to other hospitals before transferring to the trauma center. A retrospective analysis of patients with TBI in the state of Virginia was carried out to access if direct transport of patients with TBI to trauma center improves the outcome compare …

The Impact Of Registered Apprenticeships On The Middle-Skills Gap In Virginia, Yolanda Macklin Crewe

Theses and Dissertations

The skills gap debate has raged among scholars and policymakers for the last few decades. The key questions are whether the gap exists, the extent of the gap and how to minimize the gap. Of particular concern is a skills gap for middle-skills occupations. Since 2014, the federal government has invested over $500 million in registered apprenticeships as a strategy to address the skills gap. Likewise, Virginia has invested over $7.5 million and implemented policies such as VA Executive Order 49 (EO49), to expand registered apprenticeships as a workforce strategy to diminish the skills gap.

The goal of this research …

An Integrated Exploration Of The Contextual, Relational, And Individual Factors That Impact High School Completion Among African Americans, Lesley B. Winchester

Theses and Dissertations

African American students are consistently reported as having among the lowest high school graduation rates when compared to other races (U.S. Department of Education, 2018). While many studies have sought to explore the potential risks of high school dropout, the intention of this study is to examine the factors that support the exemplary resilience of those students who do complete high school. The present study adopts the framework of García Coll et al.’s, (1996) integrative model of developmental competencies in minority children, as it seeks to identity whether and how contextual (spiritual, educational, cultural); relational (caregiver psychological and physical …

The Effect Of The Senolytic Abt-263 On Androgen Deprivation-Induced Senescent Prostate Tumor Cells, So Min Lee

Theses and Dissertations

Prostate cancer (PCa) is one of the leading causes of cancer-related deaths in men. Although standard treatments such as androgen deprivation therapies (ADT) and antiandrogens have increased survival for many patients, most men placed on these therapies will develop castration-resistant disease (CRPC). Previous studies have shown that these treatments have limited cytotoxicity and instead promote cell growth arrest. Our current work demonstrates that prostate tumor cells grown in the absence of androgens by using charcoal-stripped serum undergo senescence-mediated or senescent-like growth arrest, based on the cellular expression of senescence-associated-beta-galactosidase (SA-β-Gal). Our studies further suggest that this senescence is transient and …

Competing Models Of Exposure To Community Violence Among Urban Youth: Dimensional Versus Person-Centered Approaches, Sarah K. Pittman

Theses and Dissertations

Exposure to community violence is prevalent among urban youth residing in neighborhoods with high rates of crime and violence. Although there is strong evidence suggesting that community violence exposure is associated with negative consequences on youth development, there are inconsistencies in theories and evidence regarding the nature of these associations. Methodological limitations of dimensional approaches to conceptualizing exposure, including the assumption that adolescents are similar in their frequency and patterns of exposure, likely contribute to the inconsistencies in findings of associations. Recently, person-centered methods have been used to elucidate associations between community violence exposure and consequences on adolescent development. However, …