Digital Commons Network^™

Improving Feature Learning Capability And Interpretability Of Unsupervised Neural Networks, Chathurika S. Wickramasinghe Brahmana

Theses and Dissertations

The motivation for this dissertation is two-prong. Firstly, the current state of machine learning imposes the need for unsupervised Machine Learning (ML). Secondly, once such models are developed, a deeper understanding of ML models is necessary for humans to adapt and use such models.

Real-world systems generate massive amounts of unlabeled data at rapid speed, limiting the usability of state-of-the-art supervised machine learning approaches. Further, the manual labeling process is expensive, time-consuming, and requires the expertise of the data. Therefore, the existing supervised learning algorithms are unable to take advantage of the abundance of real-world unlabeled data. Thus, relying on …

Temporal Disambiguation Of Relative Temporal Expressions In Clinical Texts Using Temporally Fine-Tuned Contextual Word Embeddings., Amy L. Olex

Theses and Dissertations

Temporal reasoning is the ability to extract and assimilate temporal information to reconstruct a series of events such that they can be reasoned over to answer questions involving time. Temporal reasoning in the clinical domain is challenging due to specialized medical terms and nomenclature, shorthand notation, fragmented text, a variety of writing styles used by different medical units, redundancy of information that has to be reconciled, and an increased number of temporal references as compared to general domain texts. Work in the area of clinical temporal reasoning has progressed, but the current state-of-the-art still has a ways to go before …

Advancing Forest Structure-Function Relationships: Linking Above- And Belowground Structure To Soil Respiration, Laura J. Hickey

Theses and Dissertations

Variation in the soil-to-atmosphere C flux, or soil respiration (Rs), is influenced by a suite of biotic and abiotic factors, including soil temperature, soil moisture, and root biomass. However, whether canopy structure is tied to soil respiration through its simultaneous influence over these drivers is not known. We assessed relationships between measures of above- and belowground vegetation density and complexity, and evaluated whether Rs is linked to remotely sensed canopy structure through pathways mediated by established biotic and abiotic mechanisms. Our results revealed that, at stand-scale, canopy rugosity–a measure of complexity–and vegetation area index were coupled to soil respiration through …

Peri-Implantitis Incidence And Effect Of Supportive Periodontal Therapy On Outcomes: Retrospective Cohort Study, Michael Ha

Theses and Dissertations

Purpose: Management of peri-implantitis is becoming an increasing component of dental practice. Dental implants can develop peri-implantitis lesions which occur in a non‐linear and accelerating pattern compared to a gradual periodontitis lesion. It is crucial to diagnose and treat this disease early, or ideally prevent it. Contemporary implants have a rough surface texture which is difficult to properly decontaminate as a crucial component for treatment prognosis. Evidence on the long-term effects of Periodontal implant maintenance therapy (PIMT) on implants is limited. This study aims to investigate the effect of periodontal maintenance on peri-implant tissue health.

Methods: A retrospective chart review …

Detailing The Genetic And Environmental Influences Shared Between Conventional And Electronic Cigarette Use Across Measures Of Initiation And Past 12-Month Use, James Clifford

Theses and Dissertations

Introduction. Tobacco use is a public health crisis with nearly 500,000 Americans suffering premature mortality attributable to tobacco use in 2014. New development efforts have created new nicotine delivery systems whose health consequences are not yet fully understood such as electronic cigarettes (ECIG). It is possible there are shared genetic and environmental factors that influence an individual’s liability to initiate cigarette (CIG) or ECIG use, as both systems are designed to deliver nicotine.

Methods. Four study designs were used to resolve the genetic and environmental influences that underlie CIG and ECIG initiation. A twin study, scoping review, genome-wide association study …

Mathematical Models Of Infection Prevention Programs In Hospital Settings, Kelly A. Reagan

Theses and Dissertations

Hospitals play a vital role in providing for the healthcare needs of a community. Patients can develop hospital-acquired infections (HAIs) during their hospitalization due to exposure to foreign bacteria, viruses, and fungi. Infection prevention programs target and reduce HAIs, but implementing the infection prevention programs often comes with a cost. The goal of my research is to use mathematical models to quantify the impact of infection prevention programs on cases of HAIs and total healthcare costs. First, I use a Markov chain model to quantify how one infection prevention program reduces general HAIs in the hospital. Then, I calculate the …

Synthesis And Modeling Of Manganese Ferrite Nanoparticles For Magnetic Hyperthermia Applications, Margaret E. Thornton

Theses and Dissertations

Biologically targeted magnetic hyperthermia (MH) is a promising cancer therapeutic that is both non-invasive and has the potential to serve as a single-modality cancer treatment. MH operates through the elevation of temperatures between 40-43 °C to induce apoptosis in malignant tumor cells, while the small size of the magnetic nanoparticles preserves the healthy surrounding tissue. At present, MH is limited by low heating efficiency and heterogenous outcomes, and treatment requires direct-injection of the nanoparticles, excluding deep-tissue and metastatic tumors from the therapy. The most popular candidates for MH are the spinel ferrites iron oxide and manganese iron oxide (MFO). These …

Analysis Of Microdroplets And Microorganisms By Single Entity Electrochemistry, Junaid U. Ahmed

Theses and Dissertations

Single Entity Electrochemistry (SEE) is an emerging electrochemical technique that has been used to characterize discrete entities by measuring the change in current or potential during individual stochastic events (collision or adsorption) of an entity with an ultramicroelectrode (UME) of similar dimensions. The shape and magnitude of the SEE signal depend on the underlying mechanism of interaction with the UME surface. There is a critical need for quantitative models that correlate the SEE signal with properties of the entity-UME system, including effects of acquisition instrumentation, to prevent misinterpretation of data.

This research focused on integrated experiments and simulations to quantify …

Antiviral Effects Of Metalloshielding: Differential Antiviral Activity Of Polynuclear Platinum And Cobalt Compounds, Mary Zoepfl

Theses and Dissertations

The majority of antiviral drug development has focused on virus-specific discovery targeting discrete steps in the individual life cycles. Although great strides have been made for a number of clinically relevant diseases such as human immunodeficiency virus, influenza virus, and hepatitis B, broad spectrum antivirals do not exist. Broad spectrum antivirals would offer (1) treatment for viruses without specifically-targeted antivirals, (2) treatment for viruses which have developed resistance to their available treatments, and (3) a rapidly deployable treatment option in viral epidemics. Many viruses including human cytomegalovirus (HCMV), HIV, and SARS-CoV-2. rely on heparan sulfate (HS), a highly sulfated glycosaminoglycan …

Metamosque – Envisioning The Mosque As A Virtual Public Space, Alaa Albarazy

Theses and Dissertations

Historically, the mosque was not only a space for a communal prayer but also a place for building a community. Today, however, with conflicts and diseases fragmenting society, people are less able to gather physically in large spaces. Out of necessity, people rely on technology to get together and interact virtually. In this context, my research challenges the notion of the mosque as a physical space, proposing, instead, its extension into virtual space. Recent global events pose the question: Can the metaverse offer an opportunity for the mosque to reassert itself as a public space. I propose that a MetaMosque …

Detection And Reporting Of Child Abuse And Neglect: A Survey Amongst Pediatric Dental Care Providers In The United States, Daniel J. Lander

Theses and Dissertations

Purpose: The purpose of this study is to survey pediatric dental care providers in the United States to evaluate their knowledge in the detection and reporting of child abuse and neglect (CAN). Methods: This study has been modeled as a cross sectional- survey based research study. Email invitations were sent to pediatric dentists, orthodontists, and others who work in pediatric dental practices in the United States through email lists of the American Association of Pediatric Dentists (AAPD) and the American Association of Orthodontists (AAO). The survey completion page included sample text and the public survey link for providers to use …

How Is Biophilic Urbanism Being Used In Planning To Rejuvenate Post-Industrial Cities?, Andrea A. Kerley

Theses and Dissertations

ARE POST-INDUSTRIAL CITIES USING BIOPHILIC URBANISM TO MERGE NATURE AND THE BUILT ENVIRONMENT? A PLAN EVALUATION OF FOUR U.S. LEGACY CITIES

By Andrea (Andi) Ames Kerley, Master in Urban and Regional Planning

A thesis submitted in partial fulfillment of the requirements for the degree of Master of Urban and Regional Planning, at Virginia Commonwealth University.

Virginia Commonwealth University, 2020.

Major Director: Megan Z. Gough, Associate Professor, L. Douglas Wilder School of Government and Public Affairs,

Urban and Regional Studies and Planning

The re-imaging of U.S. post-industrial cities from desolate, impoverished, and polluted areas to unique, equitable, and environmentally aware cities …

Wet, Flowering, Dry, Caroline A. Minchew

Theses and Dissertations

Wet, flowering, dry is a series of photographic works that explore how vernal pools are a macrocosm for holding memory and a site of omnipresent solitude and decay. This installation distills an embodied and ephemeral experience of how we are grounded in a network of invisible connections with our surroundings. This network becomes evident through biological, historical, and field research conducted at the vernal pools for over a year. Through slow observation and consideration of how multiple stories of place can weave together into a larger parable, Wet, flowering, dry reveals how the life cycle of a vernal pool is …

Traumatic Brain Injury-Induced Changes Of Immune/Inflammatory Response In The Context Of Predisposition Of Alzheimer’S Disease, Alexandra Pedin

Theses and Dissertations

Alzheimer’s Disease (AD) is a progressive neurogenerative disease that affects millions globally. At this time there are no effective treatment options as the primary cause for AD is not fully understood. In addition to old age, genetic predisposition, and certain health conditions, traumatic brain injury (TBI) has been identified as a risk factor for AD. While the pathway that links TBI to AD is still largely unknown, the neuroinflammatory response to both conditions has been connected to the NLRP3 inflammasome. Due to its role in the innate immune system and proinflammatory cytokine mediation, the NLRP3 inflammasome could be a potential …

Defiantly Childlike: Using Aesthetic Resistance To Heal, Sarah K. Reagan

Theses and Dissertations

This thesis examines an alternative processing mechanism surrounding the act of healing after traumatic experiences in life. Using a methodology of iterative patterning and tool-pathing, a collection of inflatable garments and wooden mannequins analyzes defense mechanisms learned in early childhood development. This work highlights an essential body of recent scholarship that takes cuteification seriously to restore a childlike approach to mastering fear. This paper will review the definitions of cuteness and childlike humor and then describe how visual culture has implemented these components to subvert established power.

Periodic Trends In The Infrared And Optical Absorption Spectra Of Metal Chalcogenide Clusters, Alain Ward

Theses and Dissertations

We have investigated the Optical absorption, Infrared spectra, Binding Energies, and various other cluster properties to determine the existence of periodic trend for Transition Metal Chalcogenide Clusters ligated with CO ligands. We were motivated to answer the question of whether periodic behavior can be observed in properties of octahedral metal-chalcogenide clusters. We have used the Amsterdam Density Functional code to calculate the electronic structure of Transition Metal Chalcogenide Clusters using gradient-corrected density functional theory. We determined the existence of several periodic trends in properties of octahedral Transition Metal Chalcogenide Clusters TM₆Se₈(CO)₆. To investigate these …

Connections Exposed | A Library For The People, Stephanie Wilburn

Theses and Dissertations

MOTIVATION

The U.S. economy, democracy, and the health and happiness of citizens depends on maintaining social capital, the networks of bonds between community members. Social capital creates the trust that facilitates action and cooperation for mutual benefit. Since the 1960s, there has been a decline in-person socialization and social bonds both within and between demographic groups in the US resulting in reduced social capital (Putnam, 2000).

One measure to combat declining social capital is to create third places where incidental and repeated social interactions build and reinforce bonds between community members (Oldenburg, 1997).

With the reduction of accessible and inclusive …

Towards New Antimalarial Drug: Depolarization Of Liposomal Membranes By Aminooxoethylcarbamothioate In The Presence Of Fe3+ Ions, Aaron Wilson

Theses and Dissertations

Despite the efforts of scientists around the world 409,000 people died of malaria in 2019 alone. According to the WHO 90% of those deaths occurred in Africa. Despite the high number of available treatments, malaria continues to plague many parts of the world. This is due in part to drug resistance developed among mosquito populations as well as limited access to medicines that do work. Furthermore, when traveling to malaria prone areas, pretreatment with a chemoprophylaxis is common practice. However, often the side effects to malaria pretreatment are severe. A new approach to the treatment of malaria is a compound …

Chronic Adolescent Stress As A Predictive Factor For The Risk Of Developing Ptsd-Like Symptoms In Adulthood, Grace K. Young

Theses and Dissertations

Post-traumatic stress disorder is a stress and trauma based psychological disorder that is defined by the DSM-IV as an anxiety disorder that affects approximately 7.8% of people in the United States. PTSD is when those who suffer a traumatic event have intense and distressing feelings, emotions, and memories for a prolonged period of time after the event. A prominent feature of PTSD is the impaired ability to properly extinguish a fear response after a dangerous trigger or stressor is no longer present, also known as safety learning. Stressors are threats perceived within the environment that activate a response within the …

It Takes A Muscle: Wholes, Holes, And Other Voids, Saar Shemesh

Theses and Dissertations

IT TAKES A MUSCLE¹

In the BELLY of the BEAST, the HUMAN

in the deep end of a SWIMMING POOL

in a GRAVE, looking up/out from within

at the base of a CRATER, ABYSS, PIT

the room as a CRADLE, INCUBATOR

architecture as MOTHER MOULD.²

____________________________

¹ Title is borrowed and abbreviated: Spectral Display, “It Takes A Muscle To Fall In Love,” 1982.

² For what American-English delineates as ‘mold,’ British-English uses ‘mould’ and is more specific in its technicality. The former doesn’t distinguish in spelling between mold (fungus) and mold (mould). I’m not particularly a fan of …

Human Papillomavirus 16 E2 Regulates Host Cell Pathways Important For Cancer Progression And Treatment Sensitivity Which May Contribute To Cancer Outcomes, Christian Fontan

Theses and Dissertations

Human papillomaviruses (HPVs) are causative agents in around 5% of all cancers, including cervical and oropharyngeal. A feature of HPV cancers is their better clinical outcome compared with non-HPV anatomical counterparts. In turn, the presence of E2 predicts a better clinical outcome in HPV-positive cancers; the reason(s) for the better outcome of E2-positive patients is not fully understood.

Previously, we demonstrated that HPV16 E2 regulates host gene transcription that is relevant to the HPV16 lifecycle in N/Tert-1 cells. One of the genes repressed by E2 and the entire HPV16 genome in N/Tert-1 cells is TWIST1. In these studies, we demonstrate …

Multi-Modality Automatic Lung Tumor Segmentation Method Using Deep Learning And Radiomics, Siqiu Wang

Theses and Dissertations

Delineation of the tumor volume is the initial and fundamental step in the radiotherapy planning process. The current clinical practice of manual delineation is time-consuming and suffers from observer variability. This work seeks to develop an effective automatic framework to produce clinically usable lung tumor segmentations. First, to facilitate the development and validation of our methodology, an expansive database of planning CTs, diagnostic PETs, and manual tumor segmentations was curated, and an image registration and preprocessing pipeline was established. Then a deep learning neural network was constructed and optimized to utilize dual-modality PET and CT images for lung tumor segmentation. …

Modeling Of Patient-Specific Periaortic Mechanics And Pulmonary Artery Hemodynamics Based On Phase-Contrast Magnetic Resonance Imaging Sequences., Johane H. Bracamonte

Theses and Dissertations

Inverse modeling in cardiovascular medicine is a collection of methodologies that can provide non-invasive patient-specific estimations of clinical risk factors using medical imaging as inputs. Its incorporation into clinical practice has the potential to improve diagnosis and treatment planning with low associated risks and costs.

Herein, three different phase contrast magnetic resonance imaging (MRI) modalities were implemented as input data, displacement encoding with stimulated echoes (DENSE MRI) applied, and time-resolved velocity encoding phase-contrast MRI, in 1D and 3D, applied to pulmonary artery (PA) hemodynamics.

A model to account for the effect of periaortic interactions due to static and dynamic structures …

Using Molecularly Imprinted Polymers For The Selective Extraction Of Analytes, Haley A. Mulder

Theses and Dissertations

Sample preparation is a critical steps in bioanalysis. Traditional methods such as solid-phase extraction and liquid-liquid extraction are laborious and ultimately incapable of properly separating target analytes from matrix and interferents. The co-extraction of these components interferes with the analytical instrument’s ability to properly detect and quantitate analytes. Molecularly imprinted polymers (MIPs) are synthetic polymers that have been “imprinted” with a template analyte in a co-polymer system. MIPs are capable of selectively extracting analytes from complex biological matrices and can be employed in off-line, benchtop extractions or for on/in-line instrument extractions. MIPs offer faster and more selective sample preparation, leading …

Modulating Ketamine’S Locomotor Activating And Reinforcing Effects Through Drug Combinations, Tegshjargal Baasansukh

Theses and Dissertations

Major Depressive Disorder (MDD) affects approximately 280 million people worldwide. The standard of care for pharmacological treatment of MDD has been monoaminergic antidepressants (MAA). However, MAAs have serious clinical limitations including a relatively slow onset of action and up to 40% of patients failing to respond and being diagnosed as “treatment resistant”. Ketamine, an N-methyl-D-aspartate antagonist, was originally approved for use as an injectable anesthetic. In addition, ketamine has been shown to rapidly improve depressive symptoms in patients with treatment resistant depression. In 2019, (S)-ketamine was approved as a nasal spray (Spravato®) for patients with MDD and treatment-resistant depression in …

A Case Study Exploring How The Zero Barriers In Stem Education Professional Development Program Affects Attitudes And Confidence Toward Teaching Stem Content To Students With Disabilities, Alison Dossick

Theses and Dissertations

This study was designed to assess how the Zero Barriers in STEM Education professional development (PD) course affected teacher attitudes and confidence in teaching science, technology, engineering, and mathematics (STEM) content to students with disabilities. A convergent mixed-methods case study analysis was used. The research questions were devised by examining answers on a pre-survey and post-survey. Documentation included a full analysis of two pre- and post-surveys, teacher implementation logs, team action plans, program evaluations, and semi-structured interviews. Barriers included time to plan and implement the outlined strategies and administrative and colleague support. This research uncovered some of the difficulties of …

Academic Health Science Centers And Health Disparities: A Qualitative Review Of The Intervening Role Of The Electronic Health Record And Social Determinants Of Health, Wies Rafi

Theses and Dissertations

Literature on the magnitude of negative health outcomes from health disparities is voluminous. Defined as the health effects of racism, environmental injustice, forms of discrimination, biases in science, and sociological or socioeconomic predictors across populations, health disparities are part of an ongoing and complicated national problem that health equity programs are specifically designed to address. Academic Health Science Centers (AHC) institutions are a complex and unique educational-healthcare ecosystem that often serves as a safety net for patients in vulnerable and lower-income communities. These institutions are often viewed as one of the most uniquely positioned entities in the U.S. with an …

Supported Employment Services And Employment Outcomes For Low-Income Youth With Intellectual And Developmental Disabilities: A Case Control Study, Hannah Seward Phd

Theses and Dissertations

Transition-age youth, ages 14-24 years old, with intellectual and developmental disabilities (IDD) face unique barriers to entering the labor force when exiting high school. These barriers can be even more severe if the youth is from a low-income background. Supported employment (SE) services may help this population overcome these barriers and be employed in competitive integrated employment (CIE) settings. SE provides an employment specialist to guide them through obtaining and retaining a job (McDonough & Whittenburg, 2020; Wehman et al., 2007). However, limited research has been done on the SE experiences and outcomes of transition-age youth with IDD (Wehman et …

Alcohol And Other Addictive Behaviors Among Bariatric Surgery Patients, Rachel M. Arnold

Theses and Dissertations

Research has repeatedly highlighted a high rate of comorbidity of addictive behaviors in both clinical and non-clinical samples. While polydrug use has received significant attention in recent years, less is known about rates of comorbidity with behavioral addictions such as eating, work, exercise, or sex. Individuals with a history of bariatric surgery may provide a unique opportunity to examine the potential co-occurrence of addictive behaviors. High rates of food addiction symptoms and changes in alcohol use patterns post-surgically have highlighted a potential gap in our understanding of bariatric patients and their needs post-surgically. Using a composite measure of addictive behaviors, …

Modification Of Culture Medium And Identification Of Microbial Contaminants For Improved In Vitro Propagation Of Freshwater Mussels, Raquel M. Wetzell

Theses and Dissertations

In vitro propagation efforts play an essential role in conserving and restoring threatened freshwater mussel populations by circumventing the need for a fish host. Across a broad range of taxa, transformation is induced with an artificial M199 medium and rabbit serum. However, such formulation may not be sufficient in culturing critical species with more specific physiological requirements. In this study, multiple serum mixtures were tested to improve in vitro transformation of two freshwater mussel species: yellow lampmussel (Lampsilis cariosa) and tidewater mucket (Atlantaconcha ochracea). These species were selected because they parasitize similar fish host species but …