Digital Commons Network^™

In Vitro Investigation Of Macrophage Functional And Metabolic Modulation, Shelby Nicole Bess

Graduate Theses and Dissertations

Macrophages are a subset of immune cells with a variety of functions that are abundant in numerous tumor types such as colorectal and breast cancer. It has been suggested that macrophages may serve an important function as immune mediators in tumor behavior; however, macrophage activity is complex and remains not completely understood. The overall goal of this dissertation was to explore and exploit tumor-associated macrophage phagocytic function and the changes in their interactions with cancer cells in an in vitro mouse model and in 2D and 3D in vitro culture models. First, we wanted to better understand macrophage behavior under …

Applying A Strained Masculinity Framework To Honor Killings And Incel Murders, Shreeya Gandhi

Graduate Theses and Dissertations

The current study explores how pursuits of hegemonic masculinity can shape the comparative nature of Gender Based Violence (GBV), specifically incel killings and honor killings, in the United States over the past 30 years. Drawing from Allison and Klein's (2021) strained masculinity framework and employing a homicide narrative approach, a qualitative theme analysis is conducted to determine whether existing thematic categories of strained masculinity determined relevant in prior research also apply to these relatively are forms of deadly GBV. Honor killing data come from Hayes, Freilich & Chermak (2016) and incel killing data come from the Extremist Crime Database (ECDB). …

Exploring The Relationship Between Technical College Faculty Members’ Length Of Teaching Experience And Their Moral Identity, William Abney

Graduate Theses and Dissertations

This study investigates the relationship between faculty members’ length of teaching experience and their moral identity at a technical college in the Southeastern United States. Utilizing a quantitative approach, the research aims to determine whether a significant correlation exists between an instructor’s tenure in postsecondary education and their moral identity, as measured by the Moral Identity Questionnaire (MIQ). Additionally, the study examines the potential moderating effect of gender on this relationship. Data will be collected through a Qualtrics electronic survey distributed to all faculty members at the college, ensuring anonymity and minimizing survey errors. The survey includes demographic questions and …

In Search Of Real Truth And Accurate History: Protecting And Resisting Whiteness In Education Policy Discourse, Rachel Piontak

Graduate Theses and Dissertations

This research examines whiteness in education policymaking through a three-article dissertation, contributing to the broader understanding of how whiteness manifests across education policy and legislative discourse. The first article presents a comprehensive scoping review of critical whiteness studies (CWS) in education policy research. Using CWS tenets such as whiteness as property and colorblind racial ideologies, the analysis identifies themes of manipulated discourse, the economics of whiteness in education, and the protection of whiteness. This study anchors the second and third studies, which examine whiteness ideologies at play within the education policymaking discourse of the American Southeast. The second article addresses …

Elucidating The Mechanisms Of Collagenase H From Hathewaya (Clostridium) Histolytica In Collagen Degradation And Developing A Cross-Linked Platform For Efficient Capture And Release Of Adeno-Associated Virus Serotype 2 (Aav2), Adjoa Otubea Bonsu

Graduate Theses and Dissertations

In biological systems, Hathewaya (Clostridium) histolytica secretes collagenases that degrade structural collagen in host tissues and cause tissue necrosis. Despite their detrimental effects, these enzymes have significant therapeutic potential by effectively digesting various collagen subtypes to treat connective tissue disorders. The bacterium produces two homologous collagenases, ColG and ColH, with a catalytic module crucial for hydrolyzing collagen and binding domains, including collagen-binding domains (CBDs) and polycystic kidney disease-like domains (PKDs), for substrate interaction.

Although the crystal structure of the catalytic module of collagenase G (ColG) has been determined, shedding light on its chew-and-digest mechanism, the structure of collagenase H (ColH) …

Investigating The Impact Of Gear Up Arkansas On College Readiness And Post-Secondary Enrollment In The Delta, Erika Mcmahan

Graduate Theses and Dissertations

This study evaluates the impact of the Gaining Early Awareness and Readiness for Undergraduate Programs (GEAR UP) Arkansas initiative on improving college readiness and postsecondary enrollment among low-socioeconomic status (SES) students in the Arkansas Delta, a region marked by systemic educational inequities and persistent poverty. Framed by Opportunity Gap Theory, this quantitative, quasi-experimental research addresses two questions: (1) How does GEAR UP participation influence postsecondary enrollment compared to nonparticipants? (2) Do participants achieve higher ACT scores than nonparticipants? Using data from 491 students across high-poverty schools, the study employs logistic regression to assess enrollment rates and multiple regression to analyze …

Exploring Latent Mediation Through Bayesian Regularization Methods Of Lasso, Ridge, Horseshoe, Spike-And-Slab, Ethan Harris

Graduate Theses and Dissertations

Regularization is a powerful tool to combat overfitting and drive sparsity in complex models. Regularization was initially applied in regression modeling but has been increasingly utilized in structural equation modeling where its utility in identifying the essential components has helped improve modeling. As structural equation models have increased in complexity both in the number of indicators but also the number of latent factors, researchers have begun to investigate how applying Bayesian regularization to these systems can further push the limits on modeling complex models with limited sample sizes. One area where research is limited is the application of Bayesian regularizations …

Comparison Of Airborne Lidar-Derived Elevation Data In Fayetteville, Arkansas, Usa, Angelica M. Otting

Graduate Theses and Dissertations

Light detection and ranging (lidar) laser scanners are prominent remote sensing tools to produce high resolution three-dimensional (3D) imagery of the Earth’s surface. These laser scanners combined with global navigation satellite systems (GNSS) and real-time kinematic (RTK) reference stations can generate some of the most accurate ground surface imagery and elevation data for terrain mapping and related applications. Lidar aerial survey is an important tool in industries such as architecture, civil engineering, forestry, geology, geography, and agriculture where digital terrain models (DTMs) can be used to examine the geographical landscape and urban industry. Currently, there are three different common laser …

Contrastive Learning Techniques For Fraud Detection, Vinay Madanbhavi Shashidhar

Graduate Theses and Dissertations

Detecting fraud in computing platforms involves identifying malicious user sessions, often using deep learning models, but several challenges hinder effective deployment. Attackers can craft diverse malicious sessions that closely resemble normal ones, complicating the learning of robust decision boundaries. While supervised contrastive learning offers a promising solution through class-specific clustering, its potential remains underexplored. Real-world datasets typically contain few labeled malicious sessions and many normal ones, creating an open-set anomaly detection challenge. Costly expert annotation further limits labeled data, especially for smaller organizations, leading to Positive Unlabeled (PU) learning and noisy label learning issues. Organizations are increasingly turning to LLMs …

Impacts Of Toxic Fescue Seed Consumed By Pregnant Heifers On Maternal Blood Flow And Offspring Growth Parameters: Potential For Melatonin As A Therapeutic To Improve Offspring Growth, Rachel Scott

Graduate Theses and Dissertations

The southeastern United States is home to endophyte-infected (E+), toxic, tall fescue grass. Consumption of E+ fescue by livestock has been linked to fescue toxicosis, a disease reported to cost the United States beef industry around $1 billion in annual losses. The primary objective of this dissertation was to evaluate the influence of pregnant cattle consuming E+ seed during gestation on uterine artery blood flow and growth performance of female offspring. The secondary objective was to investigate melatonin supplementation as a mitigation strategy for expected fescue-associated decreases in uterine artery blood flow and offspring growth performance. The study reported in …

Shaping Minds, Shaping Future: Analyzing K-12 Climate Change Education Policy Preferences In Arkansas, Nataliia Borozdina

Graduate Theses and Dissertations

Climate change education in K-12 public schools is a highly debated and divisive policy issue, particularly in politically conservative states such as Arkansas, where ideological divisions often dominate and shape public attitudes and policy preferences. This dissertation examines the attitudes, preferences, and behavioral intentions of three key stakeholder groups, namely the policy elites, general public, and educators toward climate change education policies in K-12 public schools in the state of Arkansas. While political party affiliation is an important factor, this study explores a more nuanced relationship by considering the interplay of Cultural Theory, risk perception, trust in government, climate change …

Adversarial Machine Learning: Methods For Attacks And Defenses, Minh Hao Van

Graduate Theses and Dissertations

With the rapid development of machine learning in real-world applications, enhancing security plays an important role. Adversarial machine learning focuses on understanding malicious actions from attackers and developing defensive techniques against such threats when deploying machine learning systems. An attack can occur in different scenarios, such as poisoning attacks during the training stage and evasion attacks during the testing stage. Although extensive research has explored defense strategies to deal with these harmful attacks, there is a need for further research into areas such as how to counteract malicious attacks with healthy noise or how to train an adaptive defense against …

Principal And Teacher Perceptions Of Corrective And Developmental Feedback For Teachers, John Kimball Emett

Graduate Theses and Dissertations

This study explores why the current structures of systematic, comprehensive, instrument-driven, and inter-rater reliable teacher evaluation may oversimplify the multi-dimensionality of teaching and minimize practitioner voices in the field. A framework for teaching complexity is presented with descriptions of effective school culture and connectivity, educator well-being, connected relationships, reflection for continual improvement, and positive learning environments. Through a mixed method, bounded multiple case study, and descriptive survey research, I sought to understand principal and teacher perceptions along inquiry lines of feedback going well and not going well in both corrective and developmental settings. I probed reflexively with purposive sampling, five …

Real Time Adaptive Control Of A Pid Via Genetic Algorithm Machine Learning Systems, Cemre Tas

Graduate Theses and Dissertations

The most common control method that is utilized by all industries across the world is the proportional-integrative-derivative controller (PID) due the relatively low cost and complexity of the system. However, there are draw-backs with PIDs, it is not adaptative to a changing system, so it works on nominal systems, and it starts breaking down when a system begins to have a non-linear response. The method chosen to overcome both is the utilization of machine learning with the use of genetic algorithms.

This method allows any PID system to be capable of adapting in real-time, while not adding significant additional cost …

Controls On Nutrient And Sediment Export In A Non-Perennial Agricultural Stream, Kathleen Cutting

Graduate Theses and Dissertations

Climate change is expected to increase flow variability and intermittency in streams, changing the magnitude and timing nutrient and sediment delivery. This may exacerbate water quality issues in agricultural landscapes, where nutrient and sediment inputs are often elevated. Elevated nutrients can drive eutrophication in downstream waterways, and excess sediment loss can decrease primary productivity. Non-perennial headwater streams are particularly vulnerable to the impacts of climate change and agriculture as they serve as key sites for nutrient cycling at the terrestrial-aquatic interface. Despite their importance, the interactive effects of agriculture and stream intermittency, as well as unpaved roads in rural watersheds …

Cartographic Representation And Analysis Of Sand Dune Morphometry In Wadi Rum, Jordan, Grace Clark

Graduate Theses and Dissertations

Situated in southern Jordan, near the Saudi Arabia border, Wadi Rum boasts a dramatic landscape of towering sandstone inselbergs and vast dune fields. The UNESCO World Heritage site is known for its cultural, historical, and physical uniqueness. Due to the hyper-arid environment and sandstone weathering, the region provides a perfect outdoor laboratory for aeolian research.

While research on aeolian processes has grown in popularity in the past century, there is a lack of conventional cartographic and visualization techniques in the field of aeolian studies. This project corroborates findings from influential aeolian researchers such as R.A. Bagnold while also implementing traditional …

Effects Of Cholesterol Concentration On Liposome And Proteoliposome Behavior, Ehsaneh Khodadadi

Graduate Theses and Dissertations

Cholesterol is crucial in modulating the behavior and characteristics of biological membranes, liposomes, and proteoliposomes, for instance in drug delivery applications. Cholesterol regulates membrane stability by influencing lipid density, phase separation, and protein-membrane interactions. In planar bilayers, cholesterol enhances membrane thickness, reduces permeability, and promotes lipid ordering, adding rigidity and fluidity. Cholesterol also modulates membrane curvature in curved bilayers and vesicles, stabilizing low-curvature regions. In this work, all-atom molecular dynamics (MD) simulations were employed to examine how varying cholesterol concentrations influence the structure and dynamics of membranes, focusing on planar and curved geometries. Bilayers with cholesterol molar ratios of 0%, …

Regulatory Compliance Standards And Power System Reliability: A Study On Inverter-Based Resources, Pirouz Honarmand

Graduate Theses and Dissertations

The increasing penetration of renewable energy, particularly inverter-based resources (IBRs), has reshaped the dynamics of modern power systems. This thesis investigates the impact of regulatory compliance, especially frequency ride-through requirements under NERC PRC-029-1, on the performance and reliability of interconnected multi-area systems. Using a MATLAB/Simulink-based state-space model built on the foundational structure proposed by Murty [31] and augmented with advanced control methods such as Linear Quadratic Regulator (LQR) control from Mackey and McCann [32] and further refined in the context of IBR damping by Alsarray and McCann [33], we explore three configurations of a three-area load frequency control (LFC) system. …

Evolutionarily Conserved Functions Of The Gene Frazzled In Midline Axon Guidance In Drosophila Melanogaster And Tribolium Castaneum., Piyasi Ghosh

Graduate Theses and Dissertations

Axon guidance in bilaterians is often controlled by various signaling pathways in the nervous system, which determine the fate of the axons if they cross the midline or not. One such pathway involved is the ligand-receptor pair Netrin (Net) and Frazzled (Fra), which is also known as the attractive pathway that promotes midline crossing axons in insects and other bilaterians. Orthologs of the pathway ligand Netrins and their receptors Frazzled [Fra] in insects and Deleted in Colorectal cancer [DCC] in vertebrates are widely conserved in bilaterians. How well these regulatory roles of the protein are conserved is poorly understood. In …

Atomic Level Characterization For The Transport Cycle Conformational Pathways Of Multidrug Resistance Protein 1 (Mrp1), Samuel Wamwere Mwatha

Graduate Theses and Dissertations

The multidrug resistance-associated protein 1 (MRP1/ABCC1) is an ATP-binding cassette (ABC) transporter that mediates the cellular efflux of endogenous and xenobiotic substrates, including therapeutic drugs. Its overexpression is a major contributor to multidrug resistance in cancer, which tends to result in negative clinical results. Even with considerable progress made in structural biology, the intricate details of how membrane lipid composition affects the conformational changes and functional switches of MRP1 still lack explanation.

This thesis employs long-timescale, all-atom molecular dynamics (MD) simulations to study the influence of various lipids on MRP1 lipid bilayer environments. Both inward-facing and outward-facing conformations of MRP1 …

Investigating Evolution Through The Lens Of Ai-Driven Protein Exploration And Phylogenetic Modeling, Mataya Duncan

Graduate Theses and Dissertations

Recent advances in computational biology, artificial intelligence, and sequencing technologies have enabled new perspectives for addressing longstanding questions in evolutionary biology. Increased computational power has made large-scale simulations feasible for investigating diverse aspects of evolutionary and phylogenetic modeling. Similarly, deep learning algorithms now allow for the prediction of reasonably accurate tertiary protein structures, unlocking the potential for investigating diversity and evolution of protein structure across a broad range of organisms. This thesis presents two studies that target different aspects of evolutionary inference from unique perspectives. Yet, the share an overarching goal of presenting new perspectives on the evolutionary basis of …

Utility Of John Deere's See & Spray Ultimate In Southern U.S. Row Crops, Tristen Avent

Graduate Theses and Dissertations

Row crop producers across the southern United States are observing a boom in technological advancement to improve operational efficiency. Additionally, environmental concerns and reduced profit margins drive the adoption of targeted pesticide application technologies like the John Deere See & Spray. This technology is relatively new, introduced in 2022, and producers need more insight into the shortcomings, potential herbicide savings, and the economic benefits of adoption. Since 2021, research has been conducted in Keiser, AR, with additional collaborative projects in Mississippi, North Carolina, Indiana, and Illinois. Five different objectives were addressed in this research: 1) to determine the impact of …

Crispy Not Risky: Effects Of Environmental Conditions On Low-Moisture Food Persistent Bacterial Pathogens, Manita Adhikari

Graduate Theses and Dissertations

Low-moisture foods (LMFs) were not historically seen as safety risks due to their ability to inhibit pathogen growth, but evidence shows pathogens can survive in LMFs long-term, causing outbreaks and recalls. Previous studies have lacked the ability to replicate real-world contamination scenarios in LMF processing environments. This research aimed to develop inoculation methods to form LMF persistent bacterial populations (LMF PBPs) and assess pathogen responses to environmental factors, culturing methods (broth vs. lawn), and matrix type and ratio. Inoculation methods tested were “direct” (combining bacterial culture and powder on a stainless-steel coupon) and “slurry” (premixing culture and powder). Matrices included …

Application Of Ordinal Regression Models To Acquired Stress Resistance In Wild Strains Of Saccharomyces Cerevisiae, Carson Stacy

Graduate Theses and Dissertations

This thesis explores the application of ordinal regression to the analysis of semi-quantitative growth assays often used when comparing fitness for different strains of the model yeast Saccharomyces cerevisiae. For stress survival assays, yeast stress resistance is measured using an ordered survival score that ranges from 0 (no growth) to 4 (confluent growth). Traditional approaches to analyze this type of data either treats data as a nominal categorical variable or as a continuous numerical variable. These approaches risk loss of information or violation of testing assumptions. In contrast, cumulative logit ordinal regression uses the information contained in the order …

Using Deep Learning And Two-Photon Excitation Fluorescence Microscopy To Predict Breast Cancer Recurrence And Response To Chemotherapy, Nicholas Powell

Graduate Theses and Dissertations

Accurate prediction of breast cancer recurrence plays a critical role in guiding treatment decisions, particularly regarding the use of systemic therapy for patients. While genomic assays such as the Oncotype DX Recurrence Score offer valuable prognostic information, they are limited in accessibility and application. The work presented in this thesis explores an imaging-based approach for the prediction of breast cancer recurrence that combines multiphoton microscopy (MPM) with deep learning to classify individual breast cancer biopsy samples by risk of recurrence. Genomic differences in tumors with different recurrence potentials may translate to distinct optical and structural information that can be captured …

Leveraging Machine Learning Models For Enhanced Landslide Prediction In Western North Carolina, Andrew Edmonds

Graduate Theses and Dissertations

Landslides pose significant hazards to human safety, infrastructure, and the environment, particularly in regions of high elevation that experience extended periods of heavy rainfall. This research focuses on preparing and evaluating landslide susceptibility maps (LSMs) for the Blue Ridge Mountains, a portion of the Appalachian Mountains in western North Carolina, utilizing three machine learning algorithms: Logistic Regression, Random Forest, and Gradient Boosting Regression. Sixteen landslide conditioning factors, reflecting topographic, geological, environmental, and anthropogenic influences, were identified for model input. The landslide inventory database, comprising 7,350 locations, was randomly divided into training (80%) and testing (20%) sets. The performance of each …

Implications Of Acetylation And Phosphorylation On Metabolic Enzymes, Nour Fatema

Graduate Theses and Dissertations

All living things depend on glycolysis and the TCA cycle for energy production and metabolic control. Post-translational modifications (PTMs) such as acetylation and phosphorylation, which can change enzyme activity, substrate binding, and overall metabolic balance, tightly regulate these pathways. Diseases like cancer and metabolic problems are associated with disruptions in these alterations.

Serine phosphorylation and lysine acetylation are two of the many PTMs that are evolutionarily conserved processes that alter protein function. Previously thought to be a static histone alteration, acetylation is now understood to be a dynamic regulator of metabolic enzymes that modifies contacts, charge, and conformation. In response …

In Vitro And In Vivo Evaluation Of The Effect Of A Commercial-Dried Enterococcus Faecium Fermentation Product As Quorum Sensing Inhibitors Of Salmonella Enterica Typhimurium, Ileana Loeza

Graduate Theses and Dissertations

The purpose of the present research was to evaluate Enterococcus faecium fermentation peptides (EFP) for antibacterial activity, inhibition of biofilm formation, and anti-quorum sensing properties against Salmonella Typhimurium (ST) in in vitro trials and individual body weight and ST organ colonization in therapeutic and prophylactic models in broiler chickens. Ninety-six day-of-hatch Cobb 500 broiler chickens were randomized and assigned to one of four treatments: NC) Negative Control, no EFP treatment and no ST challenge; NC+EFP) Negative Control, EFP treatment and no ST; PC) Positive Control, no EFP treatment and ST challenge, and PC+EFP) EFP treated and ST challenged. Independent trials …

Sanctuary Of The Voiceless: Examining Tik-Tok As A Political Landscape, Quentin Key

Graduate Theses and Dissertations

While studies of social media as a political landscape often focus on established platforms like Twitter. They neglect emerging spaces like TikTok, the short-form video app, which has become an unexpected hub for political discourse. This study test Melissa Harris-Perry's "everyday talk" framework to analyze the political utility of this new digital space. Through analysis of 271 posts across TikTok, Twitter/X, and Truth Social, the research reveals how platforms simultaneously enable and constrain political discourse. Findings show verified accounts post political content 3.2 times more often than regular users, while political posts receive 167% more reposts, demonstrating how algorithms amplify …

Solving Real-World Optimization Problems Using Near-Term Quantum Computing With Applications In Vehicle Routing And Drone Delivery, James Bradley Holliday

Graduate Theses and Dissertations

Quantum computing (QC) stands at the cusp of revolutionizing computation, yet its near-term potential, constrained by Noisy Intermediate-Scale Quantum (NISQ) devices, remains underexplored. This dissertation investigates how hybrid quantum-classical algorithms can address combinatorial optimization challenges in logistics, focusing on vehicle routing and drone delivery—NP-hard problems with exponential solution spaces that defy classical exhaustive methods. Amidst NISQ limitations like limited qubits and high noise, we confront key challenges: encoding complex constraints, e.g., time windows, battery capacity, into quantum models, balancing quantum and classical components for scalability, and accessing scarce quantum resources. By integrating quantum annealing (QA) and the Quantum Approximate Optimization …