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Identification Of Intracranial Lesions With Dual-Energy Computed To Mography And Magnetic Resonance Phase Imaging, Megan C. Jacobsen

Dissertations and Theses (Open Access)

On conventional Single-energy Computed Tomography (SECT), lesions with an attenuation greater than 100 Hounsfield Units (HU) can be definitively diagnosed as calcification. However, low-density calcifications and hemorrhage may have overlapping attenuation ranges between 40 and 100 HU and, therefore, cannot be differentiated with SECT alone. On T2*-weighted Gradient Recalled Echo (GRE) MRI, these lesions appear as “foci of susceptibility” in which their signal is hypointense due to the magnetic susceptibility of the lesions differing from that of the background tissue.

Dual-energy Computed Tomography (DECT) and Phase-Sensitive Magnetic Resonance Imaging (PS-MRI) represent two new imaging paradigms which both have the potential …

Aging Exacerbates Neutrophil Pathogenicity In Ischemic Stroke, Meaghan Roy-O'Reilly

Dissertations and Theses (Open Access)

Ischemic stroke is a major cause of disability and mortality worldwide. As most patients cannot receive the currently approved therapies for ischemic stroke, novel treatments are critically needed. Cerebral ischemia causes irreversible tissue damage, referred to as the “tissue core”, which is surrounded by a salvageable penumbral region. Excitotoxicity, oxidative stress and inflammation can further damage this “tissue-at-risk”, resulting in even greater functional loss and poorer injury outcomes.

Aging represents the single strongest risk factor for high mortality and poor outcome after stroke in patients. This phenotype is also seen in animal models, with aged mice experiencing higher mortality and …

Auto-Delineation Of Oropharyngeal Clinical Target Volumes Using Deep Learning Techniques, Carlos Eduardo Cardenas

Dissertations and Theses (Open Access)

Head and neck intensity modulate radiation therapy allows for the delivery of high-precision radiotherapy by conforming radiation dose to the defined treatment targets achieving more accurate target dose distribution and better sparing of normal tissues. However, producing very precise treatment plans may be ineffective if the target volumes are not defined accurately. Furthermore, there are several reports of significant inter-observer variability when delineating these target volumes for head and neck cancers making this variability one of the largest sources of uncertainty in head and neck radiation therapy.

The purpose of this study was to develop algorithms to automate target delineation …

The Role Of Perivascular Fibrosis In Post-Stroke Glymphatic Impairment And Cerebral Amyloid Angiopathy, Matthew D. Howe

Dissertations and Theses (Open Access)

In healthy brain tissue, toxic amyloid-β (Aβ) proteins are transported by the pulsatile flow of cerebrospinal fluid (CSF) along perivascular drainage pathways. Ischemic stroke may disrupt this process, leading to a perivascular build-up of Aβ, termed cerebral amyloid angiopathy (CAA). I hypothesize that an abnormal pattern of extracellular matrix deposition within the vascular basement membrane, termed fibrosis, impairs Aβ drainage from the aged brain after stroke. I further hypothesize that inhibition of astrocytic transforming growth factor-β (TGF-β) signaling can reverse these phenotypes. Finally, I also hypothesize that serum biomarkers of perivascular fibrosis can be used to diagnose CAA following intracerebral …

Changes In The Testes Following Spinal Cord Injury And The Attenuating Effects Of Licofelone, Ryan Fortune

Dissertations and Theses (Open Access)

Spinal cord injury is a devastating disease that researchers have had very limited success in treating. In addition to interrupted innervation, spinal cord injury causes pathologic changes in a multitude of organ systems. Male infertility is one such complication that is particularly devastating because the patient population is predominantly young men. Our lab has previously shown that the blood testis barrier breaks down after spinal cord injury. This dissertation shows the local metabolomic and mRNA changes that spinal cord injury causes within the testes using a Sprague Dawley rat model, including the elevation in eicosanoids, increased oxidative stress, chronically elevated …

Microrna Functions In Uv-Induced Cutaneous Squamous Cell Carcinoma, Tran Nguyen

Dissertations and Theses (Open Access)

Cutaneous squamous cell carcinoma (cuSCC) is the second most common skin cancer, for which long term UV exposure and chronic wounding are the dominant risk factors. Despite these clinically established connections, little is understood about the early molecular response of human skin to UV exposure and its connection to acute wounding and cuSCC. Thus, our goal is to find common and specific signatures driven by UV-exposure and wounding as a means of developing new approaches for treating and preventing cuSCC.

Here, we perform integrated analyses of RNA-seq and miR-seq on 3 datasets: (1) UV-unexposed and acute UV-exposed human skin, (2) …

Genomic And Transcriptomic Landscape Of Colorectal Premalignancy, Kyle Chang

Dissertations and Theses (Open Access)

Colorectal cancer (CRC) is the third most commonly diagnosed cancer among men and women in the United States, with 3 to 5 percent of the cases diagnosed in the background of a hereditary form of the disease. Biologically, CRC is divided into two groups: microsatellite instable (MSI) and chromosomally unstable (CIN). Genomic and transcriptomic characterization of CRC has emerged from large-scale studies in recent years due to the advancement of next-generation sequencing technologies. These studies have identified key genes and pathways altered in CRC and provided insights to the discovery of therapeutic targets. Despite the wealth of knowledge acquired in …

Population Codes And Their Correlates In Decision Making, Neda Shahidi

Dissertations and Theses (Open Access)

This dissertation was organized in two parts: in part 1, we discussed Neural Correlates of Perceptual Accuracy” and in part 2 we discussed “Strategy encoding in Prefrontal Cortex”.

Abstract of part 1_The accurate transmission of electrical signals within neocortex is central to sensory perception and cognition. Theoretical studies have long proposed that the temporal coordination of cortical spiking activity controls signal transmission and cognitive function. In reality, whether and how the precise temporal coordination in neuronal populations during wakefulness influences perception remains a mystery. Here, we simultaneously recorded populations of neurons in early and mid-level visual cortex (areas V1 …

Enhancing Radiation Sensitivity In Non-Small Cell Lung Cancer, Yifan Wang

Dissertations and Theses (Open Access)

Lung cancer is the leading cause of cancer-related death. While radiation therapy is one of the standard treatments for lung cancer, the disease outcome after radiotherapy is still far from satisfactory despite ongoing advances in radiation techniques. Enhancing the radiosensitivity of lung cancer has the potential to improve the disease outcome of radiation treatments. Using a novel high throughput radiation sensitizing screen, previous work in the lab has identified several potent radiation sensitizers. The focus of my dissertation is on two of the identified pathways, HSP90 and MEK, using the potent and clinically relevant inhibitors ganetespib and trametinib. Using both …

The Cross-Talk Between Neurons And Microglia Through Interleukin-4 After Ischemic Injury, Shun-Ming Ting

Dissertations and Theses (Open Access)

After ischemic stroke, the loss of blood supply to the affected region of the brain leads to a series of pathological events known as ischemic cascades, that include excitotoxicity and microglia/macrophage over-activation resulting in damaging inflammatory responses. Studies from our research group suggest that the viable neurons in the ischemic penumbra (location receiving less profound damage, as compare to ischemic core) produce and release a potent anti-inflammatory cytokine, interleukin(IL) -4. We propose that this neuronal response to sublethal ischemia is designed to guide surrounding microglia/macrophages to a reparative and anti-inflammatory (M2) phenotype.

The research included in this study is designed …

The Protective Effects Of Memantine On The Morphology And Activity Of Irradiated Dendritic Spines, Thanh Lam

Dissertations and Theses (Open Access)

Abstract: The Protective Effects of Memantine on the Morphology And

Activity of Irradiated Dendritic Spines

Thanh T. Lam, M.S.

Advisory Professor: David R. Grosshans, M.D, Ph.D.

Although radiotherapy is an effective treatment for brain tumors, the adverse effects of such treatments may result in a decline in cognitive functioning. To prevent or reverse such radiation-induced cognitive dysfunctions, it is critical to understand the cellular and subcellular effects of radiation. In this study, both Thy-1 YFP mice and cultured cortical neurons were used to investigate changes in dendritic spines after cortical neurons were irradiated. The results indicated that irradiation has long-term …

Prediction Of 1p/19q Codeletion Status In Diffuse Glioma Patients Using Preoperative Multiparametric Magnetic Resonance Imaging, Donnie Kim

Dissertations and Theses (Open Access)

A complete codeletion of chromosome 1p/19q is strongly correlated with better overall survival of diffuse glioma patients, hence determining the codeletion status early in the course of a patient’s disease would be valuable in that patient’s care. The current practice requires a surgical biopsy in order to assess the codeletion status, which exposes patients to risks and is limited in its accuracy by sampling variations. To overcome such limitations, we utilized four conventional magnetic resonance imaging sequences to predict the 1p/19q status. We extracted three sets of image-derived features, namely texture-based, topology-based, and convolutional neural network (CNN)-based, and analyzed each …

Improved Target Coverage Of Spinal Metastases Through The Use Of Flattening Filter Free Beams, Laura Bennett

Dissertations and Theses (Open Access)

Of the patients that are diagnosed with metastatic disease, up to 40% will develop vertebral osseous metastases. These metastases tend to be located in close proximity to the spinal cord itself, making it difficult to achieve the recommended minimum dose of 14 Gy for single fraction SBRT or 21 Gy¹ for three fraction SBRT while maintaining acceptable doses to the cord and cauda equina. This proximity of the target to critical structures has the potential to compromise the efficacy of the radiation treatment plan in favor of reducing normal tissue dose, resulting in poor local control and tumor recurrence …

Mir-484 Functions As An Onco-Mir In Triple Negative Breast Cancer, Nashwa Kabil

Dissertations and Theses (Open Access)

Triple negative breast cancer (TNBC) is a highly aggressive subtype of breast cancer (BC), with a poor prognosis with currently used therapies, and thus represents an unmet therapeutic challenge. Lack of molecular targets (i.e. ER, PR, HER2) and significant genetic heterogeneity are the major reasons contributing to early relapse and high mortality rates. Numerous studies have indicated that microRNAs (miRs) have an important role in BC progression, invasion, angiogenesis, and metastasis. We analyzed miRNA expression profiles of BC patient data bases and identified that miR-484 is highly upregulated in all subtypes of BC patients, with the highest expression in TNBC …

Finite-Time Anti-Synchronization Of Memristive Stochastic Bam Neural Networks With Probabilistic Time-Varying Delays, Manman Yuan, Weiping Wang, Xiong Luo, Linlin Liu, Wenbing Zhao

Electrical and Computer Engineering Faculty Publications

This paper investigates the drive-response finite-time anti-synchronization for memristive bidirectional associative memory neural networks (MBAMNNs). Firstly, a class of MBAMNNs with mixed probabilistic time-varying delays and stochastic perturbations is first formulated and analyzed in this paper. Secondly, an nonlinear control law is constructed and utilized to guarantee drive-response finite-time anti-synchronization of the neural networks. Thirdly, by employing some inequality technique and constructing an appropriate Lyapunov function, some anti-synchronization criteria are derived. Finally, a number simulation is provided to demonstrate the effectiveness of the proposed mechanism.

Trace Element Analysis Of Human Dentition From The Elite Meroitic Cemetery At Sedeinga, Sudan To Determine Dietary Consumption And Cultural Behaviors, Tiffany Lee

Electronic Theses and Dissertations

Minimal research has been conducted on the human skeletal remains from this site, and this research is aimed toward adding knowledge of the Nubian culture for the period between the 1st c. AD to the 4th c. AD, particularly focusing on answering the following questions: 1) Was intra- individual variation present in dietary consumption or cultural behaviors based on elements found within an individual's multiple molars after analysis; 2) Was an inter-individual variation apparent, based on developmental age through permanent molars, that indicated a distinction between dietary consumption against all individuals; and 3) Based on known medicinal and cosmetic use …

Comparison Of Muscle Physiology And Performance Outcomes From Either Relative Intensity Or Repetition Maximum Training, Kevin Carroll

Electronic Theses and Dissertations

The main purpose of this dissertation was to compare performance and physiological outcomes of between a repetition maximum (RM) and a relative intensity using sets-and-repetitions (RI_SR) resistance training (RT) program in well-trained lifters. Fifteen subjects underwent RT 3 d·wk^-1 for 10-weeks in either a RM group (n=8) or RI_SR group (n=7). The RM group achieved a relative maximum each day while the RI_SR group trained based on percentages. Testing included percutaneous needle biopsies of the vastus lateralis, ultrasonography, unweighted (g to assess within and between-group alterations. RI_SR from pre-to-post yielded statistically significant increases in …

Investigating The Interaction Of Monoamines And Diel Rhythmicity On Anti-Predator Behavior In An Orb-Weaving Spider, Larinioides Cornutus (Araneae: Araneae), Rebecca Wilson

Electronic Theses and Dissertations

Circadian rhythms are ubiquitous among organisms, influencing a wide array of physiological processes and behaviors including aggression. While many neurophysiological mechanisms are involved in the regulation of aggressive behaviors, relatively few studies have investigated the underlying components involved in the interplay between circadian rhythms and aggression. Spiders are an ideal model system for studying circadian regulation of aggression as they are ecologically both predators and prey. Recent studies have revealed a nocturnal orb- weaving spider Larinioides cornutus exhibits a diel and circadian rhythm in anti-predator behavior (i.e. boldness) that can be manipulated by administration of octopamine (OA) and serotonin (5- …

Role Of Ataxia-Telangiectasia Mutated Kinase In Cardiac Autophagy And Glucose Metabolism Under Ischemic Conditions, Patsy Thrasher

Electronic Theses and Dissertations

Ataxia-telangiectasia mutated kinase (ATM), a serine/threonine kinase primarily located in the nucleus, is typically activated in response to DNA damage. Individuals with mutations in ATM gene develop a disease called Ataxia telangiectasia (AT). These individuals are more susceptible to ischemic heart disease and metabolic disorder. Our lab has previously shown that ATM plays a critical role in β-adrenergic receptor (β-AR) - and myocardial infarction (MI)-stimulated myocyte apoptosis and cardiac remodeling. This study tested the hypothesis that ATM plays a critical role in cardiac autophagy and glucose metabolism following MI and ischemia, respectively. Early during MI (4 hours after its onset) …

Interprofessional Relationships In Rural Offender Re-Entry And Management: Mental Health Treatment Providers And Community Supervision Professionals, Michael Lasher

Electronic Theses and Dissertations

The current prevailing approach to managing offenders in the community involves community supervision professionals such as probation and parole officers partnering with other community professionals, such as psychologists, social workers, and other mental health providers to address offenders’ needs. Each type of professional draws from a unique field with goals, values, and theoretical orientations, which do not necessarily overlap. These relationships are rarely studied, and previous examinations are limited. The current study aims to address this deficit in the empirical literature. Drawing on data obtained from qualitative interviews, four aims were examined. First, using thematic analysis, interview data are analyzed …

Immobilization Of Gold Nanoparticles On Nitrided Carbon Fiber Ultramicroelectrodes By Direct Reduction, George Affadu-Danful

Electronic Theses and Dissertations

Due to enhanced properties such as large surface area-to-volume ratio, metal nanoparticles are often employed as catalysts for various applications. However, most studies involving nanoparticle catalysts have been conducted on collections of particles rather than single nanoparticles. Results obtained for ensemble systems can be difficult to interpret due to variations in particle loading and interparticle distance, which are often challenging to control and characterize. In this study, two immobilization strategies for incorporating gold nanoparticles (AuNPs) on carbon fiber ultramicroelectrodes (UMEs) were compared with the goal of extending these techniques to nanoelectrodes for studies of single AuNPs. Both layer-by-layer deposition of …

Quantitative Studies Of Amyloidogenic Protein Residue Interaction Networks And Abnormal Ammonia Metabolism In Neurotoxicity And Disease, Jeddidiah Griffin

Electronic Theses and Dissertations

Investigating similarities among neurological diseases can provide insight into disease processes. Two prominent commonalities of neurological diseases are the formation of amyloid deposits and altered ammonia and glutamate metabolism. Computational techniques were used to explore these processes in several neurological diseases. Residue interaction networks (RINs) abstract protein structure into a series of nodes (representing residues) and edges (representing connections between residues likely to interact). Analyzing the RINs of monomeric forms of amyloidogenic proteins for common network features revealed similarities not previously known. First, amyloidogenic variants of lysozyme were used to demonstrate the usefulness of RINs to the study of amyloidogenic …

Examining The Associative Learning And Accumbal Dopaminergic Mechanisms Of Caffeine Reinforcement, Curtis Bradley

Electronic Theses and Dissertations

Caffeine is the most consumed psychoactive substance in the world, and most caffeine consumption in coffee and energy drinks is intended to produce a psychoactive effect. However, caffeine is not a primary reinforcer in preclinical paradigms – non-human species do not reliably take the drug to produce a psychoactive effect. However, caffeine is a ‘reinforcement enhancer’ in preclinical models; the effects of caffeine increase the motivation to obtain other non-drug reinforcers. The overall goal of this project was to determine if these reinforcement enhancing effects of caffeine could promote caffeine self-administration and to subsequently investigate the behavioral and neurochemical underpinnings …

Distribution Of A Sum Of Random Variables When The Sample Size Is A Poisson Distribution, Mark Pfister

Electronic Theses and Dissertations

A probability distribution is a statistical function that describes the probability of possible outcomes in an experiment or occurrence. There are many different probability distributions that give the probability of an event happening, given some sample size n. An important question in statistics is to determine the distribution of the sum of independent random variables when the sample size n is fixed. For example, it is known that the sum of n independent Bernoulli random variables with success probability p is a Binomial distribution with parameters n and p: However, this is not true when the sample size …

Metabolic Plasticity In The Cellular Stress Response, Ying Li

Electronic Theses and Dissertations

Changes to the metabolism of the cardiomyocyte are driven by complex signaling pathways in order to adjust to stress. For instance, HIF-1α is classically known to upregulate glycolytic metabolism to compensate for oxygen deficiency. Other important effects upon glucose metabolism, which we investigate here more extensively, were also observed. Hearts derived from mice with the cardiac-restricted expression of a stabilized form of HIF-1α are remarkably ischemia stress-tolerant. Here, stable isotope-resolved metabolomic analyses were utilized to investigate glucose cardiometabolism remodeling by HIF-1αduring ischemia. We found that ¹³C-lactate accumulation was significantly elevated in HIF-1α expressing hearts while paradoxically glycogen was maintained …

3d-Printed Fluidic Devices And Incorporated Graphite Electrodes For Electrochemical Immunoassay Of Biomarker Proteins, Abdulhameed Alabdulwaheed

Electronic Theses and Dissertations

Biomarkers are measurable indicators of health status or disease state that can be used for diagnosis and may help guide patient treatment strategies. Enzyme-linked immunosorbent assays (ELISA) and other many clinical techniques currently used for measuring biomarker proteins lack sensitivity, demand high analysis cost, are often not well-suited for measuring multiple biomarkers in a single sample, and require long analysis times. Here, we demonstrate simple, low-cost 3D-printed flow-through devices with integrated electrodes modified with gold nanoparticles (AuNPs) for electrochemical immunoassays of S100B, a biomarker protein related to conditions like skin cancer and brain injuries. Flow-through devices are fabricated from photocurable-resin …

Does Light Trapping For Adult Trichoptera Improve Biomonitoring Of Stream Health In Appalachian River Systems?, Coleson Friedrich Wrege

All Theses

Rapid biomonitoring with aquatic macroinvertebrates (mostly immature life stages) is a common method to assess stream health. The use of terrestrial emerging adult aquatic insects for biomonitoring has been frequently suggested yet has not been adopted in most protocols. This study explores the addition of a light trapping protocol for adult caddisflies (Trichoptera) to complement existing rapid, multi-habitat benthic biomonitoring protocols that focus on the use of a Biotic Index. Four locations in the southern Appalachian Mountains of North and South Carolina were sampled quarterly for larvae and monthly from April through October for adults. Biotic Index values (both Mixed-Rank …

Animal Co-Products As Novel Electron Donors For Biodegradation Of Trichlorethylene, Alexander Rogier

All Theses

The United States produces approximately 55 billion pounds of animal co-products in a year. These materials are what remains once cattle, chickens, and other animals are slaughtered and the food grade material is processed for consumption. Although a substantial amount of this waste is used in the pet food industry, it leaves thousands of pounds as true waste, without a market. Given the nature of co-products, these materials have high protein and lipid content, and these waste materials have the potential to be used as electron donors for microbial processes. Animal waste co-products used as electron donor for bioremediation could …

Wishes: Modeling Characters And Environments For A Visual Narrative, Erik John Reed

All Theses

Wishes showcases character and environmental models designed for an original short animation. The story begins when a wishing coin comes to life and tries to interfere with the wish of its owner. The narrative, a quintessential romance, derives a timeless appeal from its locale, Paris. The design is inspired by digital artists like Cecille Carre, directors like Pete Docter, and painters like Eugene J. Paproski. Overall concepts and production of the models spanned five months.

Hatch Success And Population Modeling For The Critically Endangered Bog Turtle In North Carolina, Michael Donald Knoerr

All Theses

Recent literature suggests that several North Carolina bog turtle (Glyptemys muhlenbergii) populations are in decline, and many of these populations have few remaining individuals with low annual survival probability. Most populations appear dominated by older adults with few juveniles encountered; however, the proportion of juveniles encountered at two populations is dramatically higher. The reason for this variability is unknown. We conducted a nest monitoring study in 2016 and 2017 to test the hypothesis that nest survival patterns explain the observed population age structure. We collected the largest dataset yet compiled on the fate of naturally-incubated bog turtle eggs …