Digital Commons Network^™

Strategic Enhancement Of Biofuel Production Using Bacillus Subtilis As A Model Organism: A Dual Approach Of Gene Essentiality Mapping And Optimization, Angela A. Zebede

Electronic Theses and Dissertations

With rising global demand for renewable energy, enhancing microbial platforms for biofuel production is vital. This study engineered Bacillus subtilis to improve resilience to solvent stress by targeting membrane lipid biosynthesis pathways essential for integrity. Growth curve analysis (OD₆₀₀) showed that phosphatidylserine (PS) and phosphatidylethanolamine (PE) knockout strains grew significantly slower than wild type (168), indicating the importance of these lipids under stress. Laurdan fluorescence spectroscopy was used to assess membrane properties. Generalized polarization (GP) analysis revealed a concentration-dependent reduction in membrane order upon 1%–2% 1-butanol exposure. GP values declined progressively from control to 2% treatment, reflecting increased membrane fluidity …

An Income Subsystem As A Discrete Stochastic Leslie System: A Simulation-Based Approach, Fahd Nii Okantah Cobblah

Electronic Theses and Dissertations

This thesis formulates the household-income engine of an integrated population sim- ulator as a Discrete Stochastic Leslie System (DSLS). The nonnegative state vector nt ∈ Rk + aggregates income, savings, debt, employment, and transfers. (Here, the subscript + denotes the positive cone, i.e., vectors with nonnegative components). Annual evolution is linear in state, stochastic in coefficients: nt+1 = Ttnt + εt, with Tt : Rk + → Rk + cone-preserving. Exogenous macro drivers (inflation, employment, tax, salary inflation, mortgage) are forecast via ARIMA; forecasts multiply entries of Tt, preserving linearity in expectation while introducing realistic temporal correlation. The discrete-event implemented …

Synthesis Of Phenyl-Substituted Zinc Dipyrrin Photosensitizer For Carbon Dioxide Reduction, Stephen Ankomah

Electronic Theses and Dissertations

The release of CO₂ from fossil fuel combustion drives the need for its conversion into more sustainable options like CO and CH₄ via photocatalytic reduction. This process requires a catalyst, sensitizer, and electron donor. Zinc dipyrrin-based complexes are promising photosensitizers, offering an alternative to expensive, rare-metal-based systems. Most first-row transition metal dipyrrin compounds have short excited-state lifetimes due to rapid nonradiative decay, but Zn(II) dipyrrin complexes stand out. With a d¹⁰ configuration, they lack deactivating ligand field states and can access long-lived triplet states through a charge-separated intermediate. A phenyl-substituted Zn(II) dipyrrin complex was synthesized and studied using NMR to …

Divergent Responses Of Branched-Chain And Straight-Chain Lipid Membranes To Butanol Stress Revealed By All-Atom Molecular Dynamics Simulations, Joshua Olaf Aggrey

Electronic Theses and Dissertations

Membrane integrity under chemical stress is critical to cellular survival and industrial microbial bioproduction, yet the molecular basis of bilayer resilience remains poorly understood. Using all-atom molecular dynamics simulation, we compare the effect of increasing concentrations of 1‑butanol on membranes composed of straight-chain (1,2-dipalmitoyl-sn-glycero-3-phosphocholine, DPPC) and branched-chain (1-anteiso-palmitoyl-2-palmitoyl-sn-glycero-3-phosphocholine, APPC) lipids, which differ in the point of attachment of a single methyl group. In the absence of butanol, both membranes exhibit well-ordered architectures consistent with experimental benchmarks; however, under increasing solvent stress, their behaviors diverge markedly. DPPC membranes display gradual thinning, modest area per lipid …

Exploring The Impacts Of Medical Invalidation On Postpartum Parents With Pcos, Shalini Venkat

Electronic Theses and Dissertations

Individuals with polycystic ovary syndrome (PCOS) face an increased risk of poor perinatal health, yet little is known about whether negative healthcare experiences contribute toward these outcomes. Patients with PCOS have reported experiencing invalidation by healthcare providers; however, the effects of these encounters in postpartum populations remain unclear. Using data from an online survey, the current study investigated whether PCOS status moderated the relationships between invalidating communication by healthcare providers, pregnancy and birth complications, postpartum depression, and postpartum anxiety. While experiences of invalidating communication by healthcare providers predicted worse perinatal health, those with PCOS solely experienced an increased risk of …

Assembling Life From Death: Examining The Archaeological Fauna Of Jupiter Inlet Lighthouse’S Past To Preserve Biodiversity For The Future, Victoria Sherwood

Electronic Theses and Dissertations

This project utilizes an assemblage of faunal remains from a precontact midden at the Jupiter Inlet Lighthouse archaeological site in northern Palm Beach County, Florida. The assemblage was identified and analyzed through the lenses of resource use and paleoenvironmental changes. The Indigenous groups in the area heavily utilized estuarine resources such as fish and marine turtles. The archaeological assemblage was compared to a modern survey of species present at the site. The species identified in the precontact collection are present in the surrounding area today. The archaeological assemblage matching up with modern species speaks to the success of Loxahatchee River …

Predictive Factors Of Academic Success During Transition To Undergraduate Studies In Stem Programs In Kansas, Elizabeth L. Butler

Electronic Theses and Dissertations

In tThis dissertation the researcher exploreds the correlations between high school GPA, ACT Math, ACT cComposite scores, and first -semester GPA for first-time freshmen at a mid-sized university in the Midwest. This quantitative correlational study uses multiple regression analysis to discover correlations that may exist between these interval variables. Data for this study was collected through a request to the study site’s oOffice of pPlanning and aAnalysiss at the university and was all archival data at a record level for the students. Data had been collected through the admissions process and was stored in Banner and SLATE, both data management …

Consequences Of Secondary Traumatic Stress On Individuals Without Formal Psychological Training Working With Trauma-Exposed Children, Juan F. Valdez

Electronic Theses and Dissertations

Literature has suggested that secondary traumatic stress could cause various adverse effects for individuals working with trauma-exposed populations. However, direct care workers performing in shelters designed to serve unaccompanied immigrant children are faced with the task of caring for these minors who may have been exposed to trauma in their home countries, while traveling to the United States, or after arriving in the country. This qualitative case study was conducted to understand and describe the experiences of 15 current employees and five ex-employees who have worked with unaccompanied children for at least a year. These individuals participated in in-depth personal …

Sex, Riots, And Holy Water: How Modern Society Desecrates And Reconsecrates The Sacred, Jodeyah J. Mills

Electronic Theses and Dissertations

This thesis explores how modern societies desecrate and reconsecrate the sacred through rhetoric, ritual, and visual performance. Using three case studies, Nazi Germany’s transformation of Quedlinburg Abbey, the January 6th attack on the U.S. Capitol, and Sabrina Carpenter’s controversial church music video, “Feather,” this project analyzes how sacred meaning is violated and restored in religious, civic, and popular contexts. Drawing on Kenneth Burke’s dramatistic cycle and postsecular theory, it argues that desecration and reconsecration are dialogic acts that expose competing moral vocabularies within culture. Each event demonstrates that even in a secular age, people respond to ruptures of ultimate meaning …

Node-Attributed Spatial Graph Partitioning: A Kullback-Leibler Divergence Based Approach, Valentin Nechita

Electronic Theses and Dissertations

This thesis presents a novel approach to node-attributed spatial graph partitioning (NSGP) that addresses limitations in existing homogeneity measures. We introduce a Kullback-Leibler (KL) divergence-based formulation we name KLD that measures attribute similarity by comparing each node’s distribution to its subgraph centroid, providing a computationally efficient method of measuring homogeneity. Integrated within a multilevel graph partitioning framework and Fiduccia-Mattheyses refinement, our approach achieves approximately 90% runtime reduction compared to the baseline Clustering and Local Refinement (CLR) algorithm while maintaining comparable partition quality. Applied to COVID-19 infection data combined with American Community Survey demographics across U.S. FIPS codes, KLD successfully identifies …

Sampling Gear Performance And Elasmobranch Distributions In The Upper Florida Keys, Ethan L. Dewald

Electronic Theses and Dissertations

Elasmobranchs (sharks, skates, and rays) are vital marine predators, yet many populations are declining from overfishing and habitat loss. Marine protected areas like the Florida Keys National Marine Sanctuary (FKNMS) can support recovery, but knowledge gaps remain in habitat-specific community structure and survey effectiveness. I surveyed inshore (seagrass, hardbottom) and offshore (patch reef, bank reef) habitats in the Upper Florida Keys using longlines, drumlines, baited remote underwater video (BRUVs), and unmanned aerial vehicles (UAVs). Inshore assemblages showed strong habitat-driven patterns, with Ginglymostoma cirratum dominating seagrass sites, whereas offshore reefs were more homogeneous. UAVs captured the highest inshore richness, and drumlines …

Analysis Of The Submergence, Landing, And Navigation Of An Autonomous Underwater Landing Vehicle, Theresa Wainwright

Electronic Theses and Dissertations

Autonomous Underwater Landing Vehicles allow for seafloor data to be taken in multiple locations with little to no human intervention. The movement of these vehicles needs to be analyzed through simulated to ensure the correct programming of vehicle missions. This analysis includes the surface navigation, the drift experienced by the vehicle during descent, and the seafloor stability of the vehicle. The results then inform the limitations of this vehicle and the necessary adjustments to subsequent versions. Surface navigation allows understanding of vehicle movement between ascent locations, waypoints, and descent locations. Drift during descent allows for visual of the vehicle’s movements …

Sustained Cellular Survival Amid Amyloid Beta (Aβ) Burden, Giselle Shim

Electronic Theses and Dissertations

Amyloid beta (Aβ) accumulation is a hallmark of Alzheimer’s disease (AD), persisting in the brain for years. Despite its neurotoxic potential, widespread neuronal death is not consistently observed. Histopathological analysis indicates that most neurons remain viable, suggesting an altered survival state under chronic Aβ burden. This study integrates clinical, imaging, and in vitro evidence to characterize this non-lethal state. FDG-PET imaging reveals reduced glucose metabolism. In vitro, Aβ exposure leads to decreased uptake of glucose and amino acids. Reductions in ATP levels and AMPK activity indicate impaired metabolic regulation. Despite these metabolic disruptions, cell death is not observed, implying a …

Mechanisms Of Correlated Neuronal Activity In The Globus Pallidus, Hamza Albawaliz

Electronic Theses and Dissertations

This thesis investigates the mechanisms of correlated neuronal activity in the globus pallidus externus (GPe), a key structure in the basal ganglia. Neuronal activity in the GPe is reportedly decorrelated in healthy subjects but can become highly correlated in Parkinson’s disease. However, high-density neuronal recordings in the GPe of healthy rats reveal a surprising degree of correlated activity. This raises the question of whether intrinsic properties or network connectivity alone can account for such patterns. To explore this, a computational model was developed in which GPe neurons are represented as coupled phase oscillators influenced by experimentally derived phase-response curves and …

Development Of A Non-Faradaic Impedimetric Biosensor Based On Reduced Graphene Oxide For The Detection Of Brain-Derived Neurotrophic Factor (Bdnf), Mariana N. Martins

Electronic Theses and Dissertations

Neurological disorders affect millions of people worldwide. In the case of Alzheimer’s disease (AD), the rising number of cases significantly increases global healthcare costs. Therefore, early detection of biomarkers at the onset of the disease is essential for early diagnosis. This study presents an electrochemical biosensor designed for the detection of Brain-Derived Neurotrophic Factor (BDNF) in human plasma, incorporating reduced graphene oxide (rGO) to enhance signal sensitivity. Dielectrophoresis (DEP) was employed to deposit rGO flakes on the electrode surface, improving conductivity and sensor performance. Electrochemical impedance spectroscopy (EIS) was used to monitor changes in impedance associated with BDNF binding events, …

Frameworks For Repatriation: Moving Beyond Nagpra, Ashley Joplin

Electronic Theses and Dissertations

Museums and similar federally funded educational institutions have been collecting human remains since the Enlightenment era in the 1800s. Since then, these institutions have developed various collections practices that have encouraged the collection of human remains. Often unethical in nature, these collections have harmed historically marginalized communities, such as Indigenous and African American communities. While the ethics of collecting have been under scrutiny for decades, it was not until 1990 under the Native American Graves Protection and Repatriation Act (NAGPRA) that mainstream attention was drawn to the ethics of collections practices.

This thesis explores these collections practices and the repatriation …

Reproducibility In Modeling Of Knee Joint Mechanics, Maryam Nazem

Electronic Theses and Dissertations

Computational modeling of knee joint biomechanics can provide valuable insights into joint function, injury mechanisms, and patient outcomes, and can support surgical planning and informed clinical decision-making. However, achieving consistent and repeatable results, or reproducibility, is a significant challenge that affects the credibility of these models. This thesis addresses reproducibility through two studies related to the KneeHub Project, which is a multi-institutional collaboration designed to investigate reproducibility in finite-element modeling of the knee.

The first study involved model benchmarking, where predicted results of the calibrated models were compared with the experimental data to evaluate model reproducibility. While all models replicated …

Doughnut Economics And Strong Sustainability: Rethinking The Role Of Financial Investment, Isabelle Pierotti

Electronic Theses and Dissertations

This thesis investigates how private investment could align doughnut economic framework. Doughnut economics is a strong sustainability economic framework where the economy operates within planetary boundaries while ensuring social equity. Theories of sustainable development, weak sustainability, and strong sustainability are discussed to provide theoretical context for doughnut economics and mainstream economics. The analysis concludes that conventional, profit maximizing private investment does not support a doughnut economics system by supporting the depletion of natural resources and exacerbating social issues. Sustainable mainstream investment also fails to support a doughnut framework. Lastly, while impact investment is theoretically committed to social and financial returns, …

An Auto-Criticism: Exploration Of Professional Development For Secondary Science Educators, Mellissa Ann Pfaff

Electronic Theses and Dissertations

This auto-criticism investigates the benefits of experiential professional development for science educators by examining the reflective journey of one teacher-researcher—me—through multiple immersive learning experiences. Using narrative journaling and qualitative analysis, this study captures the influence of these experiences on my identity, instructional design, and ability to create experiential learning opportunities for students.

Rather than approaching professional development as a checklist of strategies, this research seeks to illuminate how deeply engaged, hands-on learning can transform teaching from routine delivery to embodied practice. Thematic coding revealed shifts in curriculum planning, increased responsiveness to student inquiry, and renewed clarity around the purpose of …

Archaeological Predictive Meta-Modeling In Pre-Columbian Mexico, Peter Stamm

Electronic Theses and Dissertations

Archaeological Predictive Modeling stands firmly as an important tool for Archaeologists to predict undiscovered sites from civilizations all across the globe. While powerful, this methodology is not without its own set of qualms. Striking a balance between pure a data-driven approach while also observing leading expert theories can be a complicated task. Going further, deciding on the specific domain of features to emphasize or overlook can be a challenge within itself, as one misstep can drastically change the output of model, sometimes for the worst. In addition, creating models that can expose their reasoning process can be rather difficult to …

Design And Synthesis Of Peptide Based Systems Of Intranasal Rna Delivery, Tamara Damjanovic

Electronic Theses and Dissertations

A promising strategy that could be used to treat many central nervous system (CNS) diseases, including Parkinson’s disease, Alzheimer’s disease and brain cancer, is through gene silencing by short interfering RNAs (siRNA). siRNA induces gene silencing by targeting complementary mRNA for degradation. However, a key challenge in the development of siRNA-based therapies for the CNS diseases is their transport across the blood–brain barrier (BBB) and blood-cerebrospinal fluid barrier (BCSFB). To facilitate the transport of siRNA across the BBB and BCSFB we have designed a siRNA delivery system based on the 17-mer naturally occurring cyclic peptide odorranalectin (OL) carrying multiple positive …

Assessing The Role Of Lead And Wax Shielding In Electron Beam Dose To Facial Tissue, Emma Abiri

Electronic Theses and Dissertations

External Beam Electron Therapy is frequently used to treat facial cancers. Wax and lead shields protect the eye lens and adjacent structures, reducing long term-complications and exposure to healthy tissues. Although these materials attenuate radiation behind the shielding, their impact on surface dose to nearby tissue requires further investigation.

This project evaluated how shielding materials influence surface dose to facial structures using MOSFET detectors on a paraffin wax phantom developed from a patient’s Dot Decimal compensator. Relative surface doses were compared for 6MeV and 9MeV electron beams under varying wax and lead shielding configurations. Results indicate that while wax and …

Humeral Head Retroversion On A Contemporary Skeletal Population With Known Physical Activity To Investigate The Differential Expressions Of Biological Sex, Elizabeth Hightower

Electronic Theses and Dissertations

Retroversion is an angled measurement of the humerus that is indicative of habitual overhand activity. Elevated retroversion measurements (in degrees) indicate overhand activity. Overhand activity indicates subsistence gathering from spear or atlatl throwing. Most retroversion research is conducted in populations where men perform more physically demanding labor. Therefore, bioarchaeologists are producing the same data over and over. Additionally, contemporary retroversion data is used as comparative figures. These subjects range from youth to professional baseball players, but the data on women is nearly obsolete. Bioarchaeology needs contemporary female retroversion data. Research was conducted at the University of Tennessee Knoxville where humeral …

The “I’M Too Much, Yet Never Enough” Paradox: A Critical Approach To Discourses Of Afro-Latinidad Among Second-Generation-Immigrant Women In South Florida, Eleni Victoria Webster

Electronic Theses and Dissertations

This study critically examines discourse and the ways it shapes identities and community belonging for self-identifying Afro-Latina, second-generation-immigrant women in South Florida. This qualitative research uses an intercultural communication framework to analyze interviews and collected poems. Informed by grounded theory and a Black feminist critical approach rooted in the intersectionality theory, the data is analyzed through comparative thematic and metaphorical rhetorical analyses. When discussing the discourses related to the development of ethno-racial identities for Afro-Latinas, certain communicative patterns of self-discovering, self-defining, and self-envisioning emerged. With regard to community belonging, three metaphorical discourses arose: not-enoughness, in-betweenness, and un-humanness. The internalization of …

Microplastic Variability In Wetland Sediments And Vegetation: A Case Study Of Spruce Bluff Preserve, Fl, Juana Maria Baudrix

Electronic Theses and Dissertations

Plastic pollution has become an imminent threat to the environment and human health. This study explores the occurrence, distribution, and retention mechanisms of microplastics (MPs) in Spruce Bluff Preserve, a 97-acre freshwater wetland ecosystem located along the eastern bank of the St. Lucie River in Port St. Lucie, FL. Understanding MP dynamics in transitional freshwater ecosystem is crucial for environmental management efforts given Florida’s heavily fragmented and managed landscape. This research specifically examined the relationship between wetland vegetation and MP retention in sediments across different ecological zones within the preserve. Surface sediment samples were collected along 8 transects of varying …

Fetal Microchimerism Of The Eye Lens, Jamie Moubarak

Electronic Theses and Dissertations

Fetal microchimerism (FMc) is the presence of a small fetal cell population in the mother, sometimes exhibiting stem cell–like properties. FMc has been observed within many placental mammal organs, except the eye. We used Yspecific PCR on genomic mouse DNA to test the hypothesis that fetal microchimerism can also be found in the lens. Of the parous females tested, we detected an Ssty2-specific amplicon in 83% (5/6) of samples and an Sry-specific amplicon in 2/4 samples. 100% (5/5) of non-age-matched parous females were positive for both primers. These results provide evidence that cells of fetal or placental origin …

Developing A High-Throughput Machine Learning Screening Platform For Genetic And Pharmacological Modulators On Caenorhabditis Elegans Seizure Behavior, Paul A. Scarpinato

Electronic Theses and Dissertations

Epilepsy is a chronic neurological disorder characterized by recurrent seizures that affect over 50 million people worldwide, including more than 3.5 million in the United States. Seizures arise from a disrupted balance between excitation and inhibition. Although antiepileptic drugs (AEDs) remain the primary treatment to restore the excitation and inhibition balance, approximately 30% of patients experience drug-resistant epilepsy, highlighting the need for additional antiseizure medications. The Caenorhabditis elegans electroshock assay was developed in relative alignment with the rodent maximal electroshock seizure (MES) test, the gold standard for preclinical AED screening, provides a cost-effective platform for prescreening candidate AEDs.

This work …

Neural Dynamics In The Cortico-Basal Ganglia-Thalamic-Cortical Loop Underlying Flexible Motor Timing, Zidan Yang

Electronic Theses and Dissertations

The ability to flexibly time actions is a fundamental aspect of voluntary motor control. The frontal cortex and striatum exhibit ramping neural activity that predicts movement initiation, suggesting they function as a core timing circuit. However, the distinct computational roles of these highly interconnected regions and the specific cell types involved have remained elusive. This thesis investigates the neural mechanisms of motor timing by combining cell-type-specific perturbations, multi-regional electrophysiology, and computational modeling in mice. First, we demonstrate that the frontal cortex and striatum play complementary roles in an adjustable timing mechanism. Transiently silencing the frontal cortex effectively “pauses” the ramping …

Lobizona And Cemetery Boys: Broadening Representation Of The Latinx/Chicanx Community, Genesis Pabon

Electronic Theses and Dissertations

This thesis focuses on two young adult speculative fiction novels, Lobizona and Cemetery Boys, that showcase the need for accurate representation of the Latinx/Chicanx and LGBTQ+ communities. Themes of sexuality, race, identity, and the gender binary within Latinx/Chicanx cultures will be explored. The narratives of the protagonists in both novels disrupt the gender binary in the United States and the Latinx/Chicanx community. There is a lack of literature that focuses on Latinx/Chicanx young adult speculative fiction, particularly in the United States, highlighting the need for more scholarly research in this area. It is essential for literary scholars and readers to …

Safe And Sound: A Polyvagal Intervention For Trauma And Therapeutic Engagement, Rebecca Nelson

Electronic Theses and Dissertations

Posttraumatic Stress Disorder (PTSD) affects approximately 5 to 8 percent of the U.S. population annually, contributing to significant healthcare costs and high psychotherapy dropout rates (Kessler et al., 2005; Kilpatrick et al., 2013; National Center for PTSD, 2023a). Understanding the factors that contribute to treatment attrition and identifying effective interventions that promote safety, engagement, and sustained participation in therapy are critical priorities in trauma counseling.

This study examined the impact of a polyvagal theory-informed intervention, the Safe and Sound Protocol (SSP), on trauma symptoms, autonomic reactivity, and the quality of the therapeutic relationship in adult clients diagnosed with trauma- and …