Digital Commons Network^™

Development Of Novel Hydrogel Materials For Viscoelastically Accurate Brain Phantoms, Lila G. Schandler

Theses and Dissertations

Current methods such as concussion tests and Magnetic Resonance Imaging (MRI) scans only reveal structural damage post-injury. Creating an anatomically accurate model of the brain that mimics brain structure and viscoelastic properties will further allow medical professionals to analyze concussion events and create curated and personalized plans of recovery for a patient’s unique brain injury.

Values have been established for the necessary viscoelastic properties (time constants and elasticity) to mimic the native human brain tissue such as grey matter and white matter. The mechanical properties of the hydrogel are tunable by varying the concentration of Phytagel (PHY), a protein binding …

Functional Monitoring For Run-Time Assurance Of A Real-Time Cyber Physical System, Matthew W. Gelber

Theses and Dissertations

As cyber-physical systems (CPS) become more integrated into everyday life, the security of these systems must also be considered during their development due to their ever-increasing importance. With the growth of physical components in the system, more autonomous control requirements, and increased dependence on proper functionality, verifying system safety and correct operation becomes increasingly difficult. CPS have become more complex through the combination of additional hardware and the resulting interconnected software in many layers, each requiring unique security solutions. One example of such a safety-critical CPS embedded system is the Flight Control System (FCS) of an Unmanned Aerial System (UAS). …

Advanced Manufacturing Methods To Produce Active Pharmaceutical Ingredients Via Parametric Control Of Crystallization, Michael Scott

Theses and Dissertations

Crystallization of pharmaceutical APIs controls the particle size, shape, and purity, all of which have direct effect on the performance and safety of the medicine. In recent years, the push to develop and understand continuous processes has enveloped the scientific community in drug manufacturing research, for both chemical reactions and crystallizations. Continuous crystallization is a relatively new field in pharmaceutical sciences and engineering. Utilization of steady state operation, combined with a depth of process understanding, enables crystallization to become a science rather than an art. Process development strategies and their results are presented for four unique active pharmaceutical ingredients in …

Investigating The Ultrafast Dissociation Dynamics Of Energetic Materials Using Femtosecond Time-Resolved Mass Spectrometry, Jacob M. Shusterman

Theses and Dissertations

Shock initiation of energetic materials produces cations and anions that can contribute to initial endothermic chemical reactions which lead to detonation. Hence, knowledge of the initial dissociation pathways of ionized energetic molecules is important for advancing the understanding of initiation mechanisms and meeting longstanding goals of the Department of Defense. Despite their potential importance, these transient charged species are difficult to detect in detonation experiments and are often ignored in molecular dynamics modeling of shocked energetic materials. However, the technique of pump-probe femtosecond time-resolved mass spectrometry (FTRMS) paired with complementary theoretical calculations can be used to elucidate initial unimolecular dissociation …

Graph Coloring Reconfiguration, Reem Mahmoud

Theses and Dissertations

Reconfiguration is the concept of moving between different solutions to a problem by transforming one solution into another using some prescribed transformation rule (move). Given two solutions s₁ and s₂ of a problem, reconfiguration asks whether there exists a sequence of moves which transforms s₁ into s₂. Reconfiguration is an area of research with many contributions towards various fields such as mathematics and computer science.
The k-coloring reconfiguration problem asks whether there exists a sequence of moves which transforms one k-coloring of a graph G into another. A move in this case is a type …

Redesign, Evaluation, And Validation Of A Commercially Viable High-Resolution Melt Based Mixture Screening Tool, Chastyn Smith

Theses and Dissertations

Analysis of evidentiary samples containing DNA from multiple contributors (“mixtures”) is a time intensive process for a forensic analyst and one where the contributor nature of a sample is not revealed until the end of the traditional forensic workflow. Often, at this stage, retesting or additional testing of mixture samples may not be possible, particularly if the DNA collection device did not preserve the DNA well enough; consequently leaving only trace amounts of a contributor’s DNA present. Thus, a new collection device that would allow for the increased preservation/integrity of evidentiary samples as well as a method that would allow …

A Precision-Controlled Investigation Into The Fundamentals Which Drive The Incredible Superhydrophobic Properties Of Soot, Ashton Bressler

Theses and Dissertations

A PRECISION-CONTROLLED INVESTIGATION INTO THE FUNDAMENTALS WHICH DRIVE THE INCREDIBLE SUPERHYDROPHOBIC PROPERTIES OF SOOT

By Ashton Bressler

A thesis submitted as a partial fulfilment of the Virginia Commonwealth University requirements for a Masters of Science at Virginia Commonwealth University.

Virginia Commonwealth University, 2024.

This thesis investigates a precision controlled superhydrophobic soot surface, composed of semi-rigid linked chains of spheres, with a radii of roughly 14um. These spheres have exceptionally useful hydrophobic properties due to; their large surface area, their large triple phase line length, their low area fraction of solid-liquid interface, their ability to deform, and their strength from both …

Using Natural Language Processing To Understand The Lived Experiences Of People Identifying With Adhd: What Themes Emerge In Social Media Posts?, Gabby C. Scalzo

Theses and Dissertations

Compared to the amount of research conducted on how to identify and understand children with Attention-Deficit Hyperactivity Disorder (ADHD), there has been relatively little work done to understand the lived experiences of adults with ADHD. Increased understanding of how adults with ADHD conceptualize themselves in the context of their diagnosis would help clinical experts tailor research and treatments to better serve these communities. However, there are several barriers towards conducting high-quality qualitative research, including time- and labor-intensity. This study, informed by qualitative research traditions, used innovative data sources (i.e., social media) and analytic techniques (i.e., machine learning) to reduce these …

A Critical Perspective On Supporting Parents In Facilitating Informal Steam Learning On Children's Early Literacy Development, Suzanne G. Alexandre

Theses and Dissertations

Considering that parents/caregivers and home environment play an influential role in a child’s school readiness and future academic success, this study sought to support parents in using facilitation strategies to engage their child in informal learning at home. In order to examine if access to support for parents of preschoolers influenced parents’ confidence in their ability to facilitate informal learning at home, the project used informal STEAM learning, for context. The study also examines the potential impact of informal STEAM learning on children's school readiness and early literacy skills and the intersections of parent involvement, STEAM, and school readiness through …

Exploring The Relationship Of Intact Limb Knee Joint Loading With Step Lengths And Step Length Symmetry In Individuals With Lower Limb Amputation, Edward D. Syrett

Theses and Dissertations

Individuals with unilateral lower limb amputation (LLA) frequently experience intact limb knee pain, dysfunction, and osteoarthritis. These problems can worsen pre-existing reductions in mobility and quality of life that this population regularly experiences. It is widely accepted that knee joint loading is implicated in the development of knee joint issues, and intact limb knee joint load alterations are thought to be widespread in individuals with LLA. Prior work suggests that gait deviations frequently present in this population may be a contributory cause of these altered forces. These deviations can take many forms, but individuals with LLA commonly demonstrate alterations in …

Investigating The Regulation Of Epithelial-Mesenchymal Transition Through Fibronectin-Mediated Tgf-Β1 Mechanotransduction Using In Vitro Models Of Triple-Negative Breast Cancer, Michael M. Sofroniou

Theses and Dissertations

TGF-β1 is a potent regulator of epithelial-mesenchymal transtion (EMT), a cellular
transdifferentation process that promotes cellular motility and matrix remodeling, critical to tumorigenesis and metastasis. TGF-β1-induced EMT promotes the assembly of FN, which synergistically binds latent TGF-β1 to aid in its activation. The purpose of of this work is to further probe the effects of autocrine TGF-β1 signaling during EMT progression by utilizing CRISPR-Cas9 deletion of the TGFB1 gene in in vitro models of triple-negative breast cancer. The studies outlined in this work demonstrate that autocrine TGF-β1 maintains a baseline level of mesenchymal marker expression. It also functions to desensitize …

Optimizing Deep Inspiration Breath Hold Technique For Personalized Breast Cancer Radiotherapy, Srinidhi Rajagopalan

Theses and Dissertations

The purpose of this research is entrenched in advancing the practice of 3D Conformal Radiation Therapy (3D CRT) for breast cancer patients by meticulously evaluating the impact of different Deep Inspiration Breath Hold (DIBH) techniques on dosimetric parameters. This study aims to ascertain the quantitative benefits of varied breathing techniques, primarily focusing on the 'Ultimate DIBH' method's efficacy in sparing critical organs such as the heart and lungs.

The comprehensive analysis of different DIBH techniques in this research is not merely an academic exercise but is geared towards substantiating the hypothesized advantages of these techniques with empirical data. By generating …

Evaluation Of Cervical Dentin Removal After Orifice Shaping In Maxillary Premolars: A Micro Ct Study, Abdulaziz Mallik

Theses and Dissertations

Objective: The research aims to compare the volume and percentage of pericervical dentin removed by Gates Glidden Drills, ProTaper SX, and a 20-06 Rotary File.

Methods: A total of 24 extracted two-rooted maxillary first premolars were divided into three groups (n=8) and were coronally flared using either Gates-Glidden Drills, ProTaper Gold SX, or a 20-06 Brasseler Endosequence CM Rotary File. Pre- and post-flaring micro-CT scans were obtained. The dentin volume of the buccal canals was measured from the chamber floor and 2 mm apically in the buccal canal only. Data were analyzed using the ANCOVA test to compare dentin removal …

Learning Curve: Designing An Inclusive Early Childhood Learning Center, Sarah Alrumayh

Theses and Dissertations

This research centers on the improvement of early childhood education environments in hopes to reduce the disparities in outcomes among children aged 2-6, widely known as "the achievement gap." It sheds light on designing an inclusive, child-centered school for students with specific learning disabilities (SLD) and speech or language impairments (SLI). Drawing on the IDEA (Individuals with Disabilities Education Act), it underscores the benefits of integrating students with special education needs into mainstream education, thereby fostering inclusive learning environments. (IDEA, 1975).

The research question probes how to create a nurturing and adaptable school environment tailored to the diverse needs of …

In Shame I Will Find Paradise, Taehee Whang

Theses and Dissertations

As a Korean American non-binary digital artist and designer, my recent explorations have focused on using voice as a medium to articulate nuanced feelings of displacement and the intricate relationships between language, identity, and expression. This journey expands beyond my personal experiences with gender dysphoria, delving into the lives of non-binary and transgender individuals undergoing gender-affirming voice therapy. Through my thesis research, I have developed interactive multimedia installations inspired by dialogues with individuals such as Umico Niwa, who traveled to Korea for voice feminization surgery, and Jeong Yoon Lee from Hyperlink Press, a four-year participant in Hormone Replacement Therapy (HRT). …

Illuminating Function And Enabling Inhibition At The Protein-Membrane Interface Of Glutathione Peroxidase 4., Courtney L. Labrecque

Theses and Dissertations

Membrane proteins act as gateways to cells and are responsible not only for signaling, lipid transport, and cellular homeostasis, but they are also integral in disease pathologies. One class of membrane proteins, peripheral membrane proteins (PMPs), reside in aqueous compartments of the cell until they are recruited to the membrane to perform their function. Glutathione peroxidase 4 (GPx4) is a PMP enzyme responsible for engaging the membrane and reducing lipid hydroperoxides, thereby preventing cellular death via ferroptosis. Due to its central function surrounding ferroptosis, GPx4 is an interesting drug target that has recently gained interest for inflammatory diseases as well …

Elucidation Of The Optical Properties Of Si And Si-Ge Alloy Nanostructures With Visible To Near-Ir Photoluminescence, Griffin Spence

Theses and Dissertations

Silicon and silicon-germanium alloy nanostructures have garnered increasing attention in the past 25 years due to their favorable optical properties, visible to near-IR luminescence, and inherently low toxicity. While many synthetic routes have been discussed in the literature, the high-temperature, solid-state disproportionation of hydrogen silsesquioxane (HSQ) has become the most popular way to produce highly crystalline, size-tunable Si and Si-based nanostructures (NCs). It has been shown in this work that maximum annealing temperature from 450°-1100°C and the addition of GeI₂or SnCl₄ precursors can be used to achieve different morphologies, alloying efficiency, and sizes. Directly annealing HSQ from …

Mathematical Modeling And Analysis Of Inflammation And Tissue Repair: Lung Inflammation And Wound Healing In Corals Under Stress, Quintessa Hay

Theses and Dissertations

A variety of insults, including tissue injury and/or exposure to pathogen, elicit an immune response in many organisms. An improperly regulated immune response can result in deleterious effects to the organism. Here we present models for lung injury in young and old mice and models for wound healing in coral reefs.

It is well known that the immune response becomes less effective in older individuals. This is of particular interest in pulmonary insults such as ventilator induced lung injury (VILI) or lung infection. We extended a mathematical model for the inflammatory response to VILI and used experimental data to select …

Large Language Models, Prompting, And Synthetic Data Generation For Continual Named Entity Recognition, Charles I. Cutler

Theses and Dissertations

With the ever-growing amount of textual data, the task of Named Entity Recognition (NER) is vital to Natural Language Processing (NLP), a field which focuses on enabling computers to understand and manipulate human language. NER enables the extraction of information from unstructured text. Accurate information extraction is crucial for applications ranging from information retrieval to systems for question-answering. To ensure that NER models are robust to changes in data distributions and capable of recognizing new entity types, one may consider expanding the capabilities of an existing model. Continual learning is a paradigm within machine learning. It studies the objective of …

Cellular Metabolism Is A Viable Therapeutic Target For Radiation-Induced Pulmonary Fibrosis, Josly Pierre-Louis Odoom

Theses and Dissertations

Herein, we provide evidence for cellular metabolic reprogramming as a driver of radiation-induced pulmonary fibrosis (RIPF). We are the first to identify a distinct metabolic signature for RIPF in a cohort of patients with radiographic sequela. We also used a RIPF mouse model to detect the metabolic pathways that enrich during pathogenesis. Our previous work highlighted the importance of lactate, a derivative of the glycolysis end-product pyruvate. Consequently, we took a special interest in the effects of radiation on the glycolysis pathway. We learned that radiation accelerates and reprograms glycolysis to an anabolic state in a pyruvate kinase M2 (PKM2)-dependent …

Towards Effective Developer Communication In Open Source Software Via Emotional Awareness, Mia Mohammad Imran

Theses and Dissertations

Emotions play an integral yet understudied role in open-source software development, profoundly shaping critical collaborative processes such as knowledge sharing, decision-making, and team dynamics. However, accurately detecting and analyzing emotions in developer communications poses significant challenges due to the lack of visual and auditory cues in text-based interactions. This dissertation investigates techniques to enhance the understanding and modeling of emotions within the textual artifacts of open-source projects. We conduct an extensive evaluation of existing emotion classification tools using a novel dataset of annotated GitHub comments. An error analysis reveals deficiencies in handling implicit emotional expressions and figurative language. We demonstrate …

Problems In Graph Theory With Applications To Topology And Modeling Rna, Rayan K. Ibrahim

Theses and Dissertations

In this thesis, we explore four projects. In the first project, we explore $r$-neighbor bootstrap percolation on a graph $G$. We establish upper bounds for the number of vertices required to percolate in the case that $r=2$ for particular classes of graphs. In the second project, we study the structure of graphs with independence number two. We prove a lower bound on the number of edges of such graphs, related to an upper bound on the number of edges in a triangle-saturated graph, and give a sufficient forbidden induced subgraph condition for independence number two graphs. In the third project, …

Mathematical Analysis Of Eukaryotic Pericentromere, Puranjan Ghimire

Theses and Dissertations

The centromere is crucial for chromosomal stability and their proper segregation during cell division in eukaryotes. Surrounding the centromere are pericentromeres, made of repetitive DNA elements called pericentromeric repeats, varying from 10 in fission yeast to thousands in humans. These repeats form densely packed heterochromatin, where genes are usually silenced. The silencing mechanism across different pericentromeric repeats remains unclear.

Despite variations in sequence and length, pericentromeric repeats are conserved across eukaryotes, indicating their functional importance. This dissertation presents mathematical models to quantify gene silencing in fission yeast and humans. In fission yeast, my model predicts that silencing occurs only with …

Synthesis Of Lithium Nickel Cobalt Manganese Oxide (Ncm) Cathodes For Lithium-Ion Batteries, Jethrine H. Mugumya

Theses and Dissertations

There are various ways to produce lithium nickel manganese cobalt oxide (NCM) based cathodes for lithium-ion batteries, among them; co-precipitation synthesis carried out in tank-based reactors followed by lithiation is commonly employed because of its cost-effectiveness and scalability. Although it is the preferred synthesis method, it has several issues and challenges. Discussed in this dissertation are some of these issues as well as potential solutions. Physical and chemical properties of the co-precipitation product such as yield, particle size, morphology, and tap density, depend on various reaction parameters, which include pH, chelating agents, metal salt concentrations, and stirring speed. In the …

Mathematical Modeling Of Phage-Bacteria Population Dynamics, John Lawrence D. Palacios

Theses and Dissertations

Bacteriophages are viruses that infect and replicate within bacteria. Lytic phages cause the bacterial cell to burst, killing the bacteria. These types of phages can be used to treat patients with antibiotic-resistant bacterial infections. As a step in developing successful treatment protocols, we aim to understand the population dynamics of phages and bacteria using an in vitro model. We model the dynamics using the Campbell model, which consists of a delay differential equation (DDE), as a base model. We extended the model by including the emergence of phage resistance. We then compared the DDE model with a parallel ordinary differential …

Machine Learning Assisted Optimization For Calculation And Automated Tuning Of Antennas, Lauren Linkous

Theses and Dissertations

The Antenna Calculation and Autotuning Tool (AntennaCAT) software suite represents a significant advancement in the field of antenna design by automating the entire design, CAD, simulation, and optimization process compatible with several EM simulation software suites. It is the first comprehensive implementation of machine learning in this context. In particular, this work includes the capability to create and export structured datasets from the aforementioned EM software for iterative improvement and includes an expandable selection of optimizers.

Factors That Influence The Use Of Culturally Relevant And Responsive Pedagogies For Elementary School Leaders, Stephanie Lindstrom

Theses and Dissertations

The presence of minority students in public schools has highlighted the need for teachers and school leaders to seek and implement exclusive instructional strategies that will foster cultural diversity. The climate, culture, and vision of a school are a direct reflection of the school’s leadership. The purpose of this study was to explore the cultural readiness of elementary school leaders, as measured by the cultural readiness leadership scale (CRLS), and their beliefs and perceptions of culturally relevant and responsive practices. The foundational philosophy used to support this research was the transformational leadership theory. The research methodology entailed a mixed-method approach …

Torricelli's Law And The Turn-Up Number, Bianca K. Hampel

Theses and Dissertations

We investigate Torricelli's differential law for solids of revolution. Computing the ratio of times of drainage under the same circumstances (same existing requirements) but rotating the solids 180 degrees allows us to define a "Torricelli turn-up number" associated with the solid. For various solids, we calculate this turn-up number and construct solids that are not symmetric under the 180-degree rotation but with a turn-up number of 1. That allows us to construct nonsymmetric clepsydra.

Academic Performance And Educator Efficacy In Supporting Military-Connected Adolescents Among High Schools In A Georgia School District, Megan Louise Jones

Theses and Dissertations

The effects of a parent’s military service on their children are well-researched in the post-9/11 era, particularly for elementary-aged students. However, research involving adolescents is much narrower, despite 25% of all military dependents ranging between 9th and 12th grade. These students are already enduring major changes as adolescents, but military-connected adolescents are also navigating the many stressors of their family’s military affiliation. These students are oftentimes burdened by frequent moves, parental deployment, and acclimation to their circumstances. While the military family is acutely aware of the heightened stressors that potentially create chaos among the family unit, teachers’ awareness of these …

Effect Of Annealing On Photoluminescence From Defects In Gan, Oleksandr Andrieiev

Theses and Dissertations

Annealing is a critical process in modern GaN technology, essential for achieving p-type conductivity by activating the Mg_Ga acceptor, as first demonstrated by Shuji Nakamura in the early 1990s. Despite the omnipresence of hydrogen as an impurity in GaN crystals, the precise mechanisms governing hydrogen diffusion and acceptor passivation remain only partially understood. The presented research investigates the effects of annealing-induced activation and hydrogen passivation on C and Be acceptors in GaN grown by MOCVD, HVPE, and MBE methods. We explored these effects by using several annealing techniques, gas compositions, and thermal regimes. A transient behavior between the C …