Digital Commons Network^™

Data Science Methods For Standardization, Safety, And Quality Assurance In Radiation Oncology, Khajamoinuddin Syed

Theses and Dissertations

Radiation oncology is the field of medicine that deals with treating cancer patients through ionizing radiation. The clinical modality or technique used to treat the cancer patients in the radiation oncology domain is referred to as radiation therapy. Radiation therapy aims to deliver precisely measured dose irradiation to a defined tumor volume (target) with as minimal damage as possible to surrounding healthy tissue (organs-at-risk), resulting in eradication of the tumor, high quality of life, and prolongation of survival. A typical radiotherapy process requires the use of different clinical systems at various stages of the workflow. The data generated in these …

Bee Diversity Of Three Appalachian Shale Barren Sites, Olivia C. Latham

Theses and Dissertations

Insect pollination is vital to ecosystem function. However, climate change, habitat loss, pesticides, and a variety of other anthropogenic sources are contributing to a decline in pollinator diversity. Fragile small ecosystems with a high composition of specialized plant species that rely on specific pollinators such as Appalachian shale barrens, are especially at risk of losing biodiversity. This study combines the use of active sweep net sampling of endemic shale barren forbs and passive trap methods over the course of a bloom season (April-August) in three barren sites to identify bee community populations and visitation relationships between pollinator species and endemic …

Model-Based In-Vitro Pk/Pd Profiling Of Novel Synthetic Allosteric Effectors Of Hemoglobin (Aeh) As Potential Sickle Cell Disease (Scd) Therapeutics, Xiaomeng Xu

Theses and Dissertations

Introduction: Allosteric effectors of hemoglobin (AEH) represent a class of synthetic aromatic aldehydes that transiently form covalent interactions (Schiff-base) with hemoglobin (Hb) to form Hb-AEH adduct, preventing the HbS polymerization and sickling of red blood cells (RBC). The overall objective of this research was to aid in the optimization of novel AEH by understanding their target-site disposition of AEH in relevant biological matrices, e.g., HbA solution, whole blood (WB) and human liver cytosol (HLC), a surrogate of aldehyde dehydrogenase (ALDH)-mediated oxidative metabolism.

Methods: A “universal” HPLC-UV/Vis assay method was developed for the quantitation of HbA-AEH adduct for chemically …

Sphingolipids In Cancer Health Disparities And As Prospective Targets For Cancer Therapy, April E. Boyd

Theses and Dissertations

Lung cancer is the deadliest cancer both in the United States and worldwide. Non-small cell lung cancer (NSCLC) accounts for approximately 85% of all lung cancers. However, lung cancer disparities are not shared equally across racial groups, with large differences between African American and Caucasian populations. Advances in research have revealed roles of lipid mediators in cancer biology and disease progression, but sphingolipid alterations in tissues should be explored further. To address this, using mass spectrometry (MS), extensive sphingolipidomic characterization of NSCLC tumors and adjacent uninvolved tissues from African American and Caucasian patients were performed. This study revealed that NSCLC …

Verification Of The Vertical Bubble Flow Experiments, Reginald Jones Ii

Theses and Dissertations

Detailed experimental design to support basic pedagogy of flow regimes – single phase liquid, bubbly, slug, annular, dispersed droplet, and single phase vapor – occurring in flow channels of nuclear reactors has been developed for EGMN 203 - Nuclear Engineering Practicum offering at Virginia Commonwealth University’s Department of Mechanical and Nuclear Engineering. The laboratory instruction will be used to help students forming ideas and understanding flow regimes occurring in nuclear engineering applications. We designed and constructed four water columns to act as surrogates for water channels in a nuclear reactor. Each column was used for a different experiment: salted versus …

Recovery From Visual Dysfunction Following Mild Traumatic Brain Injury Is Associated With Adaptive Reorganization Of Retinal Inputs To Lateral Geniculate Nucleus In The Mouse Model Utilizing Central Fluid Percussion Injury., Vishal C. Patel

Theses and Dissertations

Traumatic brain injury (TBI) is a leading cause of morbidity and mortality nationwide. Prevalence of mild TBI (mTBI) vastly outnumbers more severe forms however the associated morbidity has only recently gained public attention. Visual dysfunction is a significant component of mTBI associated morbidity with recovery of function linked with improvement in global outcomes. Examination of sensory and motor pathways in other brain injury paradigms support that recovery is largely dependent on adaptive plasticity of remaining connections. Current examinations of visual function recovery following mTBI is limited to identifying evidence for recovery and objective evidence for adaptive plasticity is limited. Therefore, …

Integration Of Multi-Omic Platforms To Understand The Regulation Of Genes In Human Disease, Eva Lancaster

Theses and Dissertations

Epigenetic mechanisms have been hypothesized to modify gene expression (GE) in response to both genetic variation and environmental exposures, ultimately contributing to the development of complex traits. Epigenome-wide association studies (EWAS) aim to test the theory that marks of DNA methylation (DNAm) have downstream consequences that result in the development of complex diseases. Although these methods have been successful in identifying DNAm patterns in complex traits, specific molecular mechanisms involved in the etiology of complex diseases remain unidentified. This knowledge gap does not originate from a lack of DNAm-trait associations, but rather stems from study design issues that affect the …

Multi-Label Classification Models For Heterogeneous Data: An Ensemble-Based Approach., Jose Maria Moyano Murillo

Theses and Dissertations

In recent years, the multi-label classification gained attention of the scientific community given its ability to solve real-world problems where each instance of the dataset may be associated with several class labels simultaneously, such as multimedia categorization or medical problems.

The first objective of this dissertation is to perform a thorough review of the state-of-the-art ensembles of multi-label classifiers (EMLCs). Its aim is twofold: 1) study state-of-the-art ensembles of multi-label classifiers and categorize them proposing a novel taxonomy; and 2) perform an experimental study to give some tips and guidelines to select the method that perform the best according to …

Self-Assembled Metal Nanoparticle/Polymer Nanocomposites As Nanoreactors For One-Pot Reactions, Andrew Harrison

Theses and Dissertations

Polymer nanoreactors incorporating gold nanoparticle catalysts were self-assembled via Flash Nanoprecipitation. The incorporated gold nanoparticles maintained catalytic activity, which was evaluated using reduction of 4-nitrophenol with sodium borohydride as a model reaction. The diffusion coefficient for 4-nitrophenol was determined by NMR and used to calculate the second Damköhler number, which indicated that the systems were not diffusion limited. Despite similar diffusion coefficients, catalytic performance was strongly affected by the co-precipitant. For example, the apparent reaction rate per surface area using castor oil was over 8-fold greater than polystyrene. Thus, we measured the partition coefficient of 4-nitrophenol between water and castor …

Reducing Material Attractiveness Utilizing Pu-238 And U-232, Cody Lloyd

Theses and Dissertations

Decreasing the material attractiveness of uranium and plutonium materials is crucial to nuclear nonproliferation. The International Atomic Energy Agency (IAEA) implements safeguards across the world on a limited budget. Not only does decreasing material attractiveness reduce the possibility of proliferation, but also may lighten the financial burden on the IAEA if safeguards can be reduced. Two particular isotopes that have negative material attractiveness traits are ²³⁸Pu and ²³²U. Without isotopic separation technology, these isotopes cannot be removed from plutonium and uranium materials respectively. Both ²³⁸Pu and ²³²U produce large quantities of heat by alpha decay. High …

Lpa Receptors Modulate Gene Expression During Oligodendrocyte Differentiation, Samantha A. Spencer

Theses and Dissertations

LPA, produced by the lysoPLD activity of ATX, binds its cognate receptors and regulates the development of multiple brain cells, including oligodendrocytes (OLGs). OLGs progress through a lineage from precursor (OPC) to early OLG to immature OLG, until finally the cells mature and enwrap axons to enable saltatory conduction and provide trophic support. The studies in this dissertation characterized the receptors LPA4 and LPA6 as inhibitors of OPC differentiation. Western blot analysis of MS patient lesion tissue found a negative correlation between ATX levels and levels of LPA4 and LPA6. A previously created homology model for LPA4 was used to …

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 …

Stimulated Growth Response To Sand Burial Of A Coastal Shrub, D. Nicole Keller

Theses and Dissertations

Drivers of vegetation zonation on barrier islands are complex and interconnected. Sand burial is a strong driver in dynamic coastal systems, especially in the foredune community. However, it is not well understood how burial impacts the interdunal swales communities and it is especially difficult to separate the effects of burial from salinity. Climate change is altering the frequency of overwash events as well as expanding the range of the native shrub, Morella cerifera, on the Virginia barrier islands. To accurately forecast island response to climate change it is important to understand how the shrub responds to sand burial. Juvenile …

Platform And Place: The Digitization Of Gift Economies, Sara A. Peters

Theses and Dissertations

Especially during times of economic and social upheaval, such as COVID-19, people may consider alternative means of acquiring the resources necessary for survival. These lifestyle shifts, or lifestyle movements, are often associated with economic alternatives to capitalism, such as gift economies. In recent years, many of these economies have shifted to digital platforms where members create and coordinate connections for exchanges. Using a case study of The Buy Nothing Project, an international network of local, digital gift economies, this paper explores the geographic and socioeconomic conditions facilitating the presence and activity of digital Buy Nothing Groups in two US states, …

The Impact Of The Fda Warning On Post-Tonsillectomy Opioid Prescribing In Publicly And Privately Insured Children, Dianna J. Soelberg

Theses and Dissertations

Due to reports of significant adverse events, the U.S. FDA placed a Boxed Warning on the opioid codeine in February 2013 – contraindicating its use in pediatric patients undergoing tonsillectomy and/or adenoidectomy. Studies conducted in privately insured children showed a reduction in codeine prescribing and a slight increase in alterative opioid prescribing following the FDA warning, yet the extent to which the FDA warning impacted prescribing in publicly insured children is unknown. Using a quasi-experimental interrupted time series design, this study evaluated codeine and alternative opioid prescribing before and after the FDA warning in both publicly and privately insured children …

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 …

Knowledge And Skill Predictors Of Voice Behavior: Voice As An Upward Influence, Zitong Sheng

Theses and Dissertations

Abstract

In recent years, there has been a growing body of research focused on improving our understanding of employee voice behavior. Yet this literature focuses mainly on factors that influence employees’ decisions regarding whether to speak up (i.e., quantity of voice behavior), rather than factors that influence whether voice behavior turns out to be effective. As a result, job attitudes and personality characteristics have been identified as the major personal factors predicting voice behavior. The current study contributes to the voice literature by viewing voice from an upward influence angle, examining the influences of the quality of content and …

The Impact Of Occupational Therapy Acute Care Services On Readmission Rates For Patients In Medicare’S Hospital Readmission Reduction Program, Jessica M. Edelstein

Theses and Dissertations

The United States (US) health care system is faced with the daunting challenge to make healthcare payments commensurate with quality of care provided. To assess quality, metrics for reimbursement have been established by Medicare. One such quality metric is hospital readmissions (readmissions). Readmissions are associated with poor patient outcomes and costly. Associated poor patient outcomes include higher risk for mortality, deconditioning, nutritional issues and cognitive impairments. As a result, readmissions cost Medicare $26 billion annually. Current strategies for reducing readmissions in the US are fragmented and hospital-specific. While specific strategies may vary, hospitals that have low readmissions rates tend to …

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 …

Constraints On Phytoplankton Abundance And Cyanotoxin Production In The Tidal Freshwater James River, Brittany Ann Moretz

Theses and Dissertations

The tidal freshwater James River exceeds chlorophyll-a (CHL-a) water quality standards and the cyanotoxin microcystin is commonly present. Efforts to control harmful algal blooms in the James have brought about significant reductions in nitrogen and phosphorus inputs, but chlorophyll levels have not changed. In order to better understand the factors constraining harmful algal blooms in this system, we performed three factorial mesocosm experiments that tested how light (ambient, enhanced), mixing (weak mixing, well-mixed), and the availability of dissolved inorganic nitrogen (pre/post NH₄⁺ reductions) influence the abundance of phytoplankton (CHLa, particulate organic carbon [POC]) and cyanotoxin production (microcystin, anatoxin) …

A Comparison Of Computer- And Interviewer-Administered Measures To Identify Heavy/Problem Alcohol And Other Drug Use In Primary Care Patients, David J. Pomm

Theses and Dissertations

Substance use is a leading cause of morbidity and mortality that is under-identified in primary care settings. Screening for substance use in primary care requires an efficient and accurate approach. Exploring methods to collect sensitive and accurate data about substance use and related problems is important to inform research practice and clinical care. Using RCT data comparing computerized and therapist delivered brief intervention for substance use problems, the present study had a unique opportunity to compare computerized anonymous and confidential surveys to a confidential, interviewer-administered assessment in a sample of N = 540 males and females at risk for heavy/problem …

Institutional Effect: Consistency And Contingency In The Art & Pedagogy Of Josef Albers, Andrea Alvarez

Theses and Dissertations

Josef Albers (1888–1976) was an artist and educator best known for his teaching on color and for his painting series Homage to the Square, which he worked on from 1949 until his death. The symbiotic relationship between his teaching and artmaking practices, as well as the value Albers placed on the ongoing pursuit of knowledge, contributed to a lifelong commitment to teaching and learning whether he was at the Bauhaus, BMC, Yale, or in any other institutional context. This dissertation, in addition to offering a history that addresses the development of both Albers’ teaching methods and his artworks, …

Black Women And Body Image: Implications Of The Racialized Beauty Aesthetic, Rachel L. Boutte

Theses and Dissertations

Black women have the highest prevalence of overweight and obesity relative to any other demographic group in the United States, however current weight management interventions appear least effective for them. Although several hypotheses have been proposed to explain these outcomes, few studies have collected data to evaluate how well they fit the lived experiences of Black women. In particular, the potential roles of body image and body dissatisfaction in the development and maintenance of overweight and obesity in Black women are not well understood. Extant literature largely reports that Black women are inoculated from body dissatisfaction due to cultural factors, …

Design Hub: Activating Community By Design, Ed Williams

Theses and Dissertations

MOTIVATION

At the turn of the century, Robert Putnam (2000, 27) wrote “...a powerful tide bore Americans into ever deeper engagement in the life of their communities, but a few decades ago that tide reversed and we were overtaken by a treacherous rip current.” Putnam is describing a loss of “social capital” throughout American society. Research suggests that many of our contemporary issues are the result of a decline in “social capital,” or “community.”

This pervasive lack of community is thought to be detrimental to “educational performance, safe neighborhoods, equitable tax collection, democratic responsiveness, everyday honesty, and even our health …

Exosomes As Systemic Mediators Of Nanotube Induced Neurotoxicity, Christopher G. Canal

Theses and Dissertations

Extra-pulmonary effects of nanoparticle inhalation have been well documented; however, mechanisms for conveying peripheral bioactivity remain elusive. Recent studies point to indirect molecular mediators shed into the circulation. Protein and lipid alternatives to cytokines or chemokines have been proposed, yet the diversity among responses suggests a broader assemblage of factors. Recently we have proposed proteolytic fragment peptides as an additional source of bioactivity, which interestingly were significantly associated with exosomal proteins after enrichment analysis. Here we tested whether modeled exposure to multi-walled carbon nanotubes (MWCNT) could alter the composition and bioactivity of circulating exosomes. Male C57BL/6 mice were exposed by …

Adverse Childhood Experiences In Children Presenting To Integrated Pediatric Primary Care, Irene A. Jacobs

Theses and Dissertations

The prevalence of adverse childhood experiences (ACEs) has created a significant public health concern in the United States. A vast body of literature examining adult populations has displayed a dose-response association between cumulative ACEs and chronic illnesses (Chapman et al., 2004; Felitti et al., 1998). ACEs research conducted with children and adolescents has indicated higher ACE scores associated with learning and behavioral problems (Burke et al., 2011), health risk behaviors (Garrido et al., 2018), and mental health challenges (Mackner et al., 1997). However, ACEs research and subsequent interventions have largely relied upon retrospective data retrieved from adults (Felitti et al., …

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, …

Effects Of A Self-Advocacy Intervention On The Abilities Of College Students With Intellectual And Developmental Disabilities To Request Academic Accommodations, Katherine R. Brendli

Theses and Dissertations

Students with intellectual and developmental disabilities (IDD) are pursuing college at higher rates than ever before. However, many of these students experience barriers to success in college and need to self-advocate for their needs, such as requesting academic accommodations. This study examined the effects of a virtually delivered self-advocacy intervention package on the abilities of college students with IDD to request their academic accommodations. This is the first study to virtually implement a modified version of the Self-Advocacy and Conflict Resolution strategy with college students with IDD. Using a single-subject multiple-probe across participants design, this study was implemented with three …

Investigations Of Graphene-Supported Single-Atom Catalyst Model Ions In The Gas Phase, Michael Borrome

Theses and Dissertations

Recent developments in heterogeneous catalysis has led to the conception of single-atom catalysts (SACs), a class of catalysts based on isolated metal atoms anchored to a support scaffold. SACs are often much more reactive and can offer better selectivity when compared to nano-scale catalysts. In order to realize the full potential of SACs, a sound understanding of the underlying catalytic mechanisms is required. However, surface analysis tools can become less effective in studying catalytic mechanisms at the atomic scale. Mass spectrometry has proven to be a robust technique for studying organometallic catalytic mechanisms at the single-molecule level. Using mass spectrometry, …

Investigation Of Molecular Mechanisms Of Liver Preservation Injury: A Complication Preceding Organ Transplantation, Ria C. Fyffe-Freil

Theses and Dissertations

Of the over 108,000 American awaiting a life-saving organ transplant today, over 12,000 (11%) of those need a new liver (OPTN, 2020). Last year, only 35% of patients on the waiting list for an organ were transplanted. Improving the quality of marginal organs by preventing or reversing preservation injury could vastly increase the number of transplants performed. Washout of circulating blood during liver procurement with cold University of Wisconsin solution flushes out any endogenous pro-survival signaling molecules. We investigated lysophospholipid (LPL) surface receptors (G-protein coupled receptors for lysophosphatidic acid (LPA) and sphingosine- 1-phosphate (S1P)) and their role in protecting hepatocytes …