Life Sciences Commons^™

Effect Of Moderate Decrease In Contractility On Epithelial Cell-Cell Contacts Under External Stretch, Saika Sharmin

Mechanical & Aerospace Engineering Theses & Dissertations

Epithelial tissues are characterized by extensive cell–cell contacts and often subject to stretch during normal function. Cell-cell contact adhesion strength maintains mechanical continuity from cell to cell. Mechanical forces exerted by cells via actomyosin contractility are known to strengthen cell-cell adhesions to a certain extent. While it is known that a large decrease in contractility causes cell-cell contact rupture due to weakened adhesions, it is unclear how a moderate reduction in contractility affects cell-cell junction stability. Here, we studied how a moderate inhibition of non-muscle myosin II (NMII) affects the integrity of epithelial cell-cell contacts, especially when subject to the …

Effects Of Sediment Composition On Spartina Alterniflora And Juncus Roemerianus Productivity In Coastal Virginia: A Thin-Layer Sediment Placement Experiment, Caitlin Hemphill

Biological Sciences Theses & Dissertations

Climate change poses a major threat to the health of estuaries and their coastal wetland systems. The Chesapeake Bay’s coastal salt marshes are at high risk of inundation due to sea-level rise and land subsidence. Restoration techniques for maintaining coastal marsh resistance to sea-level rise are being developed and refined, with thin layer placement (TLP) emerging as a feasible solution in many areas of the United States. Despite TLPs use across the country, additional research is needed on species-specific responses, sediment types, and geographically focused studies in the lower Chesapeake Bay. My research addresses these gaps by combining both greenhouse …

Endotherm Energetics Under Environmental And Physiological Constraints, Zachary Andrew David

Biological Sciences Theses & Dissertations

Metabolic rate governs how animals allocate energy toward maintenance, activity, growth, and reproduction, linking physiology to environmental context. This dissertation investigates how two endothermic mammals regulate metabolic rate in response to environmental variability, focusing on thermoregulatory flexibility and physiological constraints. Using flow-through respirometry, I measured resting metabolic rates (RMRs) in two complementary systems: tropical bears housed in semi-natural outdoor enclosures and marsh rice rats (Oryzomys palustris) exposed to controlled thermal treatments. Asiatic black bears (Ursus thibetanus) exhibited unexpectedly low mass-specific metabolic rates even under high ambient temperatures, yet their RMR increased with temperature, suggesting proximity to their …

Advanced Analytical Biosensing For Cancer Detection And Neural Diagnostics Using Tapered Optical Fiber (Tof), Protonic, And High Throughput Microplate –Based Technologie, Bayan Hassan Alharbi

Chemistry & Biochemistry Theses & Dissertations

This dissertation investigates the development and application of advanced biosensing technologies to enhance early disease detection, neurological diagnostics, and bioactive compound evaluation. The research spans four key areas. First, it introduces tapered optical fiber (TOF)-based plasmonic biosensors for the non-invasive detection of prostate cancer, demonstrating high sensitivity and specificity compared to conventional diagnostic methods.

Second, it explores the use of fluorescent biosensors to test the Transmembrane Electrostatically Localized Proton (TELP) theory, shedding light on the role of localized protons in neuronal signaling and energy transfer. Third, the work presents a high-throughput, microplate-based biosensing platform for analyzing mitochondrial function under nanosecond …

Towards Improving Computational Modeling Of The Lumbar Spine - Impact Of Material Properties And Laminotomy On Spinal Biomechanics, Isaac K. Kumi

Mechanical & Aerospace Engineering Theses & Dissertations

Spinal ligaments play a crucial role in maintaining the mechanical stability of the lumbar spine. These dense, collagenous tissues not only resist excessive motion but also distribute loads between spinal components to protect neural structures. Traditionally, the mechanical response of ligaments has been modeled using linear elastic assumptions, which treat the tissue as having a constant stiffness regardless of loading history. While this simplifies analysis, it fails to capture the time-dependent behaviors, such as creep, stress relaxation, and hysteresis, that are characteristic of biological tissues.

Viscoelastic modeling may provide a more physiologically accurate representation by incorporating both elastic and viscous …

Using Radium Isotopes To Compare Nutrient Inputs Via Submarine Groundwater Discharge To Offshore Export On The West Florida Shelf, Andrew L. Lindgren

OES Theses and Dissertations

Radium isotopes have been used to trace submarine groundwater discharge (SGD) and associated nutrient and metal inputs into the coastal ocean. They have also been used to estimate rates of diffusive mixing and export fluxes of dissolved constituents offshore. However, use of both approaches in tandem to determine the fate of groundwater inputs after they enter the coastal ocean is still relatively unexplored. Radium isotopes and nutrients were measured in two cross-shelf cruises on the West Florida Shelf in different seasons and in quarterly sampling of offshore wells. Through 226Ra mass balance and 223Ra-derived diffusive mixing rates, inputs of nutrients …

80 - Effects Of Concussion History On Sleep Quality And Memory Function, Aubrey Thames, Amin Mohammadi, Thomas Campbell

Undergraduate Research Symposium

To examine the relationship between sleep quality and memory performance (immediate memory and delayed recall) in athletes with a history of concussion.

17 - Mapping The Spatial Distribution Of Submerged Aquatic Vegetation Using Commercial Satellite Imagery, Brandon Watson

Undergraduate Research Symposium

Seagrass in the Chesapeake Bay has seen an increase due to restoration efforts since the 90s, but with the extreme change of climate, we are unsure if the seagrass will thrive or perish, and where it will occur in the bay. Seagrass stabilizes coastal sediments, reducing erosion and protecting shorelines. It provides crucial habitats and nursery grounds for a diverse range of marine species, supporting both biodiversity and fisheries. Additionally, they play a significant role in carbon sequestration, which mitigates the effects of climate change. This study specifically looked at the area from the mouth of the Rappahannock River up …

05 - Freeze Severity And Black Mangrove Growth: Influence Of Plant Origin On Side Shoot Development, Kathryn Bourlier, Katelyn Overstreet, Erik Yando

Undergraduate Research Symposium

Despite a reduction in freeze events and subsequent expansion in the southeastern US, freeze impacts still play a critical role in mangrove morphology and local range limits. Freeze events can impair growth, limit survival, and commonly prompts side shoot development. This study examines the relationship between plant origin, freeze severity, and side shoot development in black mangroves. Our findings show that plants from each location exhibited distinct morphological responses, with similarities more closely linked to environmental conditions rather than geographic proximity. Our work offers insights into thermal tolerance thresholds and implications for mangrove stature in coastal wetlands.

02 - Habitat Preference Of Ambrosia Beetles (Curculionidae) Using Bottle Traps In Southeastern Virginia, Sajrim Chowdhury, Morgan Harrison, Deborah A. Waller, Umme Akter

Undergraduate Research Symposium

Ambrosia beetles attack host trees by boring into the stem and infecting the tree with a symbiotic fungus. Infected trees suffer damage to the vascular system which often results in tree mortality. We examined whether different species of native and invasive ambrosia beetles prefer different habitats by placing bottle traps in riparian areas near streams and in forested habitats in several locations in southeastern Virginia. Numerous ambrosia beetles were collected in the traps, and we related ambrosia beetle species to the habitat in which it was collected.

Summer Air Temperature Comparisons Between The Field And Woods In An Angus Beef Cattle Silvopasture In The Virginia Coastal Plain, Amy E. Edwards

Virginia Journal of Science

The objective of this study was to compare corresponding temperature readings from loggers in the field and woods in a silvopasture for Angus beef cattle. Results show that temperatures during the hottest part of the day are greater in the field than in the woods. Summary statistics show higher maximum, upper quartile, and median temperatures at the field logger with all data analyzed, indicating the temperatures in the field are overall higher than the woods, except during temperature inversions at nighttime. This highlights the importance of providing cattle with shade to prevent heat exhaustion and thermal stress, especially when the …

Investigating The Demography And Parasites Of Spring-Migrating Cedar Waxwings (Bombycilla Cedrorum) In Virginia After A Single-Day Mortality Event, Karen E, Powers, William W. Sadler, Acalia J. Carter-Martin, G. Caleb Smith, Gabe W. Tieskotter, Katie E. Wheeler, Matthew T. Close, Sara O'Brien, Pavel B. Klimov, Andrew D. Sweet, Stephen A. Smith, Jamie K. Lau

Virginia Journal of Science

While investigating the cause of death in a cedar waxwing (Bombycilla cedrorum) mortality event in March 2024 in Roanoke, Virginia, we collected parasites, investigated gizzard contents, and described demography. The group of 20 was slightly male-dominated (12/20) and only contained two adults (after second year - both females). We recovered 46 ectoparasites from 16 of 20 individuals and reported two species of feather mites (Proctophyllodes ampelidis [N=37] and Analges integer [N=5]), one oribatid mite, two spider mites (order Trombidiformes), and one unknown mite (likely immature oribatid). We recovered no endoparasites. This mortality event provided a sample size …

The Impacts Of Physical (In)Activity On Endothelial Function, Joel Ernest Harden

Rehabilitation Sciences Theses & Dissertations

Exercise and physical activity are known to have beneficial effects on endothelial function and vascular health. Sedentary behavior and physical inactivity, however, have been shown to be related to poor endothelial function and vascular health. The overall purpose of this dissertation was to further elucidate the physiological links between physical (in)activity and vascular health. In the first study, 12 active, young (18-40 yr) individuals and 12 active, old (55+ yr) individuals were recruited. Participants underwent 5 days of removal of exercise, and had their endothelial function assessed via flow-mediated dilation (FMD) during their normal, habitual exercise state (EX) and during …

Expanding The Lexa Bacterial Two-Hybrid System For Human Protein-Protein Interaction Screening: Application To Tumor Suppressor Par-4, Rebecca M. Richardson

Chemistry & Biochemistry Theses & Dissertations

Protein-protein interactions (PPI) are fundamental to cellular function, influencing processes such as signaling, structural organization, and disease progression. Disruptions in PPIs are implicated in cancer and neurodegenerative diseases, highlighting their importance as therapeutic targets. However, traditional methods for studying human PPIs, such as yeast two-hybrid and co-immunoprecipitation mass spectrometry, are costly and technically demanding. This dissertation explores the LexA-based bacterial two-hybrid (LexA-B2H) system as a cost effective and accessible alternative for investigating human PPIs.

This study focuses on the interaction between glucose-regulated protein 78 (GRP78) and cleaved prostate apoptosis response-4 (cl-Par-4), a tumor suppressor protein involved in apoptosis and neurodegenerative …

Development Of Flexible Lactate-Specific Molecularly Imprinted Polymers Based On Laser-Induced Graphene Electrochemical Biosensors For Disease Diagnosis, Christopher Animashaun

Biomedical Engineering Theses & Dissertations

Lactate is a critical biomarker linked to conditions such as sepsis, ischemia, cancer, and heart failure. Current lactate detection methods remain invasive, costly, and unsuitable for real-time, continuous monitoring. This study presents the development of a flexible, non-enzymatic electrochemical biosensor based on laser-induced graphene (LIG) electrodes modified with gold nanoparticles (AuNPs) and molecularly imprinted polymers (MIPs) for highly selective and sensitive lactate measurement. The integration of AuNPs enhanced surface conductivity and provided nanoscale heterogeneity, facilitating superior signal amplification. The optimized LIG/AuNP/MIP sensor achieved an extensive dynamic detection range from 0.1 μM to 1000 μM, with an outstanding detection limit of …

Low Dissolved Oxygen Operation Enhances Biological Phosphorus Removal In Wastewater Treatment, Haley Morgan

Civil & Environmental Engineering Theses & Dissertations

Biological phosphorus (bio-P) removal occurs when bacteria are exposed to anaerobic/aerobic conditions that stimulate polyphosphate-accumulating organisms (PAOs) to uptake phosphorus. In most treatment plants, dissolved oxygen (DO) concentrations in the aeration tanks are commonly at or above 2.0 mg O₂/L, which is often referred to as the most optimal aeration condition for bio-P. If bio-P can happen efficiently at lower DO (< 0.3 mg O₂/L), then the energy demand of aeration can be decreased appreciably. This research was conducted in a biological nutrient removal (BNR) pilot plant to assess the performance of bio-P at progressively lower DO operation. This …

Swinging Lever Mechanism Of Myosin Directly Shown By Time-Resolved Cryo-Em, David P. Klebl, Sean N. Mcmillan, Cristina Risi, Eva Forgacs, Betty Virok, Jennifer L. Atherton, Sarah A. Harris, Michele Stofella, Donald A. Winkelmann, Frank Sobott, Vitold E. Galkin, Peter J. Knight, Stephen P. Muench, Charlotte A. Scarfi, Howard D. White

Department of Biomedical and Translational Sciences Faculty Publications

Myosins produce force and movement in cells through interactions with F-actin¹. Generation of movement is thought to arise through actin-catalysed conversion of myosin from an ATP-generated primed (pre-powerstroke) state to a post-powerstroke state, accompanied by myosin lever swing²,³. However, the initial, primed actomyosin state has never been observed, and the mechanism by which actin catalyses myosin ATPase activity is unclear. Here, to address these issues, we performed time-resolved cryogenic electron microscopy (cryo-EM)⁴ of a myosin-5 mutant having slow hydrolysis product release⁵,⁶. Primed actomyosin was predominantly captured 10 ms after …

A Scoping Review Of Population Diversity In The Common Genomic Aberrations Of Clear Cell Renal Cell Carcinoma, Sean S. Kumar, Ninad Khandekar, Komal Dani, Saina R. Bhatt, Vinay Duddalwar, Anishka D' Souza

Department of Medicine Faculty Publications

Introduction: Previous literature has shown that clear cell renal cell carcinoma (ccRCC) is becoming a more prevalent diagnosis and that the incidence and mortality differ both regionally and racially. While the molecular profiles for ccRCC are studied regionally through biopsy and sequencing techniques, the genomic landscape and ccRCC diversity data are not well studied. We conducted a review of the known genomic data on 6 of the most clinically relevant DNA biomarkers in ccRCC: von Hippel-Lindau (vHL), Polybromo-1 (PBRM1), Breast Cancer Gene 1-Associated Protein 1 (BAP1), Histone-Lysine N-Methyltransferase Domain-Containing 2 (SETD2), Mammalian Target of Rapamycin (mTOR), and Lysine-Specific Demethylase 5C …

Synthesis And Evaluation Of Anti-Hiv Activity Of Fatty Acyl Conjugates Of Tenofovir Alefanamide, Muhammad Sajid, Naglaa Salem El-Sayed, Louise A. Ouattara, Amita Verma, Gustavo F. Doncel, Keykavous Parang, M. Iqbal Choudhary, Hina Siddiqui

CONRAD Publications

The activity of nucleoside and nucleotide analogs as antiviral agents requires phosphorylation by intracellular enzymes. Phosphate-substituted analogs have low bioavailability due to the presence of ionizable negatively-charged groups. To circumvent this limitation, several prodrug approaches have been proposed and developed. Herein, we hypothesized that the conjugation of anti-HIV fatty acids with the nucleotide tenofovir alafenamide (TAF) (1) could improve the anti-HIV activity of the nucleotide. Several fatty acyl amide conjugates of TAF were synthesized and evaluated in comparative studies with TAF. The synthesized compounds were evaluated as racemic mixtures for anti-HIV activity in vitro in a single-round HIV-1 infection assay …

Environmentally Friendly Chelation For Enhanced Algal Biomass Deashing, Agyare Asante, George Daramola, Ryan W. Davis, Sandeep Kumar

Civil & Environmental Engineering Faculty Publications

High ash content in algal biomass limits its suitability for biofuel production by reducing combustion efficiency and increasing fouling. This study presents a green deashing strategy using nitrilotriacetic acid (NTA) and deionized (DI) water to purify Scenedesmus algae, which was selected for its high ash removal potential. The optimized sequential treatment (DI, NTA chelation, and DI+NTA treatment at 90–130 °C) achieved up to 83.07% ash removal, reducing ash content from 15.2% to 3.8%. Elevated temperatures enhanced the removal of calcium, magnesium, and potassium, while heavy metals like lead and copper were reduced below detection limits. CHN analysis confirmed minimal …

Covariate Selection For Rna-Seq Differential Expression Analysis With Hidden Factor Adjustment, Farzana Noorzahan, Hyeongseon Jeon, Yet Nguyen

Mathematics & Statistics Faculty Publications

In RNA-seq data analysis, a primary objective is the identification of differentially expressed genes, which are genes that exhibit varying expression levels across different conditions of interest. It is widely known that hidden factors, such as batch effects, can substantially influence the differential expression analysis. Furthermore, apart from the primary factor of interest and unforeseen artifacts, an RNA-seq experiment typically contains multiple measured covariates, some of which may significantly affect gene expression levels, while others may not. Existing methods either address the covariate selection or the unknown artifacts separately. In this study, we investigate two integrated strategies, FSR_sva and SVAall_FSR, …

Developmental Regulation Of Corazonin, Eclosion Hormone, And Bursicon Messages And Rnai Suppression Of Corazonin In Adult Female American Dog Ticks, Dermacentor Variabilis, Anirudh Dhammi, Brooke Bissinger, Loganathan Ponnusamy, Daniel E. Sonenshine, R. Michael Roe

Biological Sciences Faculty Publications

The insect molting process is critical to growth and development and is regulated in part by the neuropeptides corazonin, eclosion hormone, and α and β bursicon. We found messages in a synganglion transcriptome from adult, female American dog ticks, Dermacentor variabilis (that do not molt), with a high similarity to the larval insect neuropeptides that control molting. The phylogenetic analysis of the tick putative neuropeptides compared to other arthropods is discussed in detail. The relative gene expression of these peptides was determined by quantitative PCR during the following adult developmental stages: (i) virgin, unfed 0–24 h after entering the adult …

A Study Of Differences In Enjoyment, Exercise Commitment, And Intention To Continue Participation Among Age Groups Of Adult Amateur Golfers, Hye Jin Yang, Ji-Hye Yang, Chulhwan Choi, Chul-Ho Bum

Human Movement Studies & Special Education Faculty Publications

Golf is one of the leisure sports that offers various benefits and has become a popular public sport with participation from people of various age groups. A total of 262 questionnaires were distributed online, with 240 valid responses collected after excluding 22 with non-responses or partial answers. The results showed statistically significant differences in enjoyment by age group, except for recognition from others. Regarding physical health, those in their 60s and above had higher mean scores than other age groups, and those in their 50s scored higher than those in their 30s. Stress relief was greater among those in their …

A Comparative Analysis Of Stress Relief, Life Satisfaction, And Quality Of Life Based On Marriage Status And Gender Among Members Of Society Participating In Exercise, Ji-Hye Yang, Sicheol Jung, Hyejin Yang, Chulhwan Choi, Chul-Ho Bum

Human Movement Studies & Special Education Faculty Publications

Modern members of society tend to feel stressed in their workplace and at home, but exercising has been shown to effectively reduce stress and increase quality of life and satisfaction. This study aimed to investigate and compare stress relief, life satisfaction, and quality of life based on marriage status and gender among members of society who participate in exercise. We used a questionnaire survey with 311 participants, and the data were analyzed using descriptive statistics, validity and reliability, a multivariate analysis of variance (MANOVA), and a post hoc analysis. The study results showed that the single groups demonstrated higher mean …

Potentiation Of Gelonin Cytotoxicity By Pulsed Electric Fields, Olga N. Pakhomova, Eleni Zivla, Giedre Silkuniene, Mantas Silkunas, Andrei G. Pakhomov

Bioelectrics Publications

Gelonin is a ribosome-inactivating protein with extreme intracellular toxicity but poor permeation into cells. Targeted disruption of cell membranes to facilitate gelonin entry is explored for cancer and tissue ablation. We demonstrate a hundreds- to thousands-fold enhancement of gelonin cytotoxicity by pulsed electric fields in the T24, U-87, and CT26 cell lines. The effective gelonin concentration to kill 50% of cells (EC₅₀) after electroporation ranged from <1 nM to about 100 nM. For intact cells, the EC₅₀ was unattainable even at the highest gelonin concentration of 1000 nM, which reduced cell survival by only 5–15%. For isoeffective electroporation treatments using 300 ns, 9 µs, and 100 µs pulses, longer pulses were more efficient at lowering gelonin EC₅₀. Increasing the electric field strength of 8, 100 µs pulses from 0.65 to 1.25 kV/cm reduced gelonin EC₅₀ from 128 nM to 0.72 nM. Conversely, the presence of 100 nM gelonin enabled a more than 20-fold reduction in the number of pulses required for equivalent cell killing. Pulsed electric field-mediated delivery of gelonin shows promise for hyperplasia ablation at concentrations sufficiently low to minimize or avoid systemic toxicity.

Traction Force Microscopy Using An Epifluorescence Microscope: Experimental Considerations And Caveats, Zaria Booth, Mazen Mezher, Rudra Patel, Venkat Maruthamuthu

Mechanical & Aerospace Engineering Faculty Publications

Forces exerted by cells due to their internal contractility play fundamental roles in a host of processes, including adhesion, migration, survival and differentiation. Traction force microscopy (TFM) enables the determination of forces exerted by cells or cell collectives on their environment, which is typically taken to be an extra-cellular matrix (ECM)-coated substrate. Sample preparation for TFM involves the plating of cells onto an environment embedded with fiducial markers. The imaging of these fiducial markers in the presence and absence of the cells then enables calculation of the displacement of localized regions of the environment, and, consequently, the spatial distribution of …

Transient Transmembrane-Electrostatically Localized Protons And Transmembrane Potential In A Laser Flashed Bacteriorhodopsin Purple Membrane Open Flat Sheet - Summary, James Weifu Lee

Chemistry & Biochemistry Faculty Publications

The transmembrane-electrostatically localized protons/cations charges (TELCs, also known as TELPs) model may serve as a unified framework to explain a wide range of bioenergetic phenomena. Transient transmembrane-electrostatically localized protons (TELPs) and transmembrane potential in a laser flash-energized bacteriorhodopsin (bR) purple membrane (PM) open flat sheet are now better analyzed. Under the Heberle et al. (1994) experimental conditions, the number of bR molecules is now calculated to be 8200 per PM open flat sheet with a diameter of 600 nm. With a single-turnover laser flash intensity of 3 mJ/cm² to photoexcite 10% of the bR molecules, the laser flash-induced peak TELCs …

Impact Of Geography On Institutions In Agricultural And Nomadic Societies, Haiwen Zhou

Economics Faculty Publications

How geography affects the choice of institutions is studied in a theoretical model. In this model, nations are located around a circle. Rulers compete through choosing tax rates, the level of military spending, and the degree of formality of institutions. Geographic condition is captured by population density. It is shown that societies with higher population densities choose lower tax rates, establish more formal institutions, and give government officials lower levels of autonomies than those with lower population densities do. A higher level of external threats induces a ruler to choose a higher level of autonomy for officials. The model is …

Gramseq-Dta: A Grammar-Based Drug-Target Affinity Prediction Approach Fusing Gene Expression Information, Kasul Debnath, Pratip Rana, Preetam Ghosh

Computer Science Faculty Publications

Drug–target affinity (DTA) prediction is a critical aspect of drug discovery. The meaningful representation of drugs and targets is crucial for accurate prediction. Using 1D string-based representations for drugs and targets is a common approach that has demonstrated good results in drug–target affinity prediction. However, these approach lacks information on the relative position of the atoms and bonds. To address this limitation, graph-based representations have been used to some extent. However, solely considering the structural aspect of drugs and targets may be insufficient for accurate DTA prediction. Integrating the functional aspect of these drugs at the genetic level can enhance …

Determination Of Structural Factors Contributing To Protection Of Zinc Fingers In Estrogen Receptor Α Through Molecular Dynamic Simulations, Patricia B. Lutz, Wesley R. Coombs, Craig A. Bayse

Chemistry & Biochemistry Faculty Publications

The ERα transcription factor that induces tumor growth is a potential target for breast cancer treatment. Each monomer of the ERα DNA-binding domain (ERαDBD) homodimer has two conserved (Cys)₄-type zinc fingers, ZF1 (N-terminal) and ZF2 (C-terminal). Electrophilic agents release Zn²⁺ by oxidizing the coordinating Cys of the more labile ZF2 to inhibit dimerization and DNA binding. Microsecond-length molecular dynamics (MD) simulations show that greater flexibility of ZF2 in the ERαDBD monomer leaves its Cys more solvent accessible and less shielded from electrophilic attack by sulfur-centered hydrogen bonds than ZF1 which is buried in the protein. In the …