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The Influence Of Cryogenic Machining On Surface Integrity And Functional Performance Of Titanium Alloys For Biomedical And Aerospace Applications, Ying Sun

Theses and Dissertations--Mechanical and Aerospace Engineering

The excellent properties of titanium alloys such as high strength, as well as good corrosion and fatigue resistance are desirable for the biomedical and aerospace industry. However, the same properties that make titanium alloys desirable in high-performance applications also make these space-age materials “difficult-to-machine” materials, as the titanium alloys exhibit high cutting temperatures because of their high strength and low thermal conductivity.

Cryogenic machining is a severe plastic deformation (SPD) processes which uses liquid nitrogen as the coolant to take away the heat generated during machining in a relatively short time. Cryogenic machining can significantly reduce the cutting temperatures at …

Development And Application Of Novel Sound Absorbers, Weiyun Liu

Theses and Dissertations--Mechanical and Aerospace Engineering

The sound absorbers in most common use today are porous materials like fibers and foams. This work examines three alternatives to porous absorbers: microperforated panels, acoustic fabrics, and additively manufactured absorbers. The research is a combination of design, measurement and characterization of their properties, and analysis.

Microperforated panels are thin metallic or plastic panels with sub-millimeter size holes or perforations. Sound absorption can be tuned by adjusting the spacing between the panel and a cavity behind the panel. Several different configurations were considered where the geometry behind the panel was divided up into channels of varying length and cross-sectional area. …

Bacterial Cell Wall Characterization Via Atomic Force And Confocal Microscopy, Joree Sandin

Theses and Dissertations--Mechanical and Aerospace Engineering

Poor oral hygiene is a severe global health issue, with about 44% of the Earth’s population suffering from untreated tooth decay, accounting for over $100 billion dollars spent on dental services per year in the United States, alone. Manual treatments, such as brushing, flossing, or swishing with antiseptic rinse are the main ways to alleviate harmful bacteria that cause these oral health problems. Streptococcus mutans (S. mutans) is a group of highly antibiotic, Gram-positive bacteria that heavily contribute to oral cavities, plaque build-up, and potential loosening or loss of dental implants if a biofilm develops. Currently, the mechanism …

Expanded Predictive Equation For Dc Arc-Flash Incident Energy In 125v Battery Systems, Austin Gaunce

Theses and Dissertations--Electrical and Computer Engineering

Arc-flash is a dangerous phenomenon that can occur during an arcing fault in an electrical system. People nearby may be subjected to extreme heat, light, pressure, and sound. Research regarding arc-flash has focused primarily on AC arc-flash due to the prevalence of AC electricity in the grid. However, the grid has begun to integrate more DC electrical sources as a result of decentralization efforts and environmental concerns. The increased proliferation of DC electrical sources demands research into DC arc-flash to assess the hazard as low-voltage DC sources have already become commonplace. Some DC arc-flash models have been produced to estimate …

Breast Implant-Associated Anaplastic Large Cell Lymphoma: Molecular Features, Epidemiological Risk Factors, And Evidence-Based Clinical Recommendations, Ryan Decoster

Theses and Dissertations--Clinical and Translational Science

Breast implant-associated anaplastic large cell lymphoma (BIA-ALCL) is an emerging cancer of the immune system that can form around textured-surface breast implants. In this dissertation, the cellular and molecular mechanisms of BIA-ALCL are reviewed with a focus on the role of oncogenic JAK-STAT3 signaling in BIA-ALCL tumorigenesis and progression. Herein, the epidemiology of BIA-ALCL is systematically studied to better define the risk of BIA-ALCL and to determine the oncologic safety of smooth surface devices relative to BIA-ALCL formation. Next, a systematic review is conducted which critically appraises current clinical guidelines in order to establish an evidence base to better inform …

The Effect Of Haptoglobin Phenotypes On Markers Of Neuroinflammation In Patients With Aneurysmal Subarachnoid Hemorrhage, Kevin Hatton

Theses and Dissertations--Clinical and Translational Science

Aneurysmal subarachnoid hemorrhage (aSAH) is a severe form of hemorrhagic stroke resulting from the spontaneous rupture of an intracranial aneurysm and release of oxygenated blood into the subarachnoid space. In the United States alone, aSAH occurs in approximately 30,000 patients each year and occurs, primarily, in otherwise healthy adults, frequently without warning. Sadly, approximately 40% of patients with aSAH will die in the first 30 days. Of those who survive, only about 75% will be able to live semi-independently again and only about 60% will be able to return to work.

Delayed brain injuries (DBI), which may affect up to …

Impact Of Nicu Design On Feeding-Related Outcomes In Preterm Infants, Emma Kate Calvert

Theses and Dissertations--Communication Sciences and Disorders

Many NICUs around the country are moving away from traditional open-bay designs in favor of single-family rooms (SFRs) as more is understood about the impact of the sensory environment on neurodevelopment in preterm infants. SFRs house one infant and their family for the length of the infant’s stay and are associated with improvements in numerous outcomes, including increased milk intake and weight gain and earlier transition to enteral feeding. Oral feeding remains a critical requirement for NICU discharge; however, the impact of NICU design on feeding outcomes remains unknown.

The purpose of this study was to compare feeding outcomes between …

Legibility Of Communicative Writing And Drawing In Aphasia: Does The Orthographic Medium Matter?, Nicole Waugaman

Theses and Dissertations--Communication Sciences and Disorders

Expressive language difficulties are commonplace in aphasia and are often further complicated by co-occurring motor speech disoders. Therefore, many people with aphasia (PWA) are unable to meet all their communication needs by speaking, and they may compensate with the use of communicative writing and drawing. Communicative writing and drawing can be defined as preserved, but imperfect, orthographic skills that PWA use to compensate for expressive language deficits resulting from aphasic and/or motor speech difficulties. The purpose of this study was to determine if the orthographic medium used by a PWA to write and draw influenced the legibility of their writing …

An Evaluation Of Postural Control And Balance After Anterior Cruciate Ligament Reconstruction, Kathryn Lucas

Theses and Dissertations--Rehabilitation Sciences

Over 100,000 anterior cruciate ligament reconstructions (ACLR) occur annually in the United States, with one in four individuals sustaining a second injury within the first two years after reconstruction. Due to the proprioceptive nature of the anterior cruciate ligament, the lack of regaining postural control and balance are likely large contributors to the rate of secondary injuries after ACLR. Recent literature has identified cerebral changes after anterior cruciate ligament injury and surgery, likely due to altered sensation and feedback loops. However, no study thus far has investigated the neurological feedback loops that may place this group at higher risk of …

Transcriptomic And Cellular Response To Mechanical Overload And The Underlying Role Of Macrophages In Extracellular Matrix Remodeling, Bailey D. Peck

Theses and Dissertations--Rehabilitation Sciences

The extracellular matrix (ECM) in skeletal muscle plays an integral role in tissue development, structural support, and force transmission. Upon mechanical loading, including resistance exercise, which alter muscle fiber contractile activity, size, orientation and connectivity, remodeling processes must occur that involve both ECM deposition and degradation. ECM remodeling involves many cell types in muscle, but the focus of our research was directed towards macrophages, which participate in the early immune response to damage and loading. We have consistently demonstrated a significant increase in skeletal muscle macrophage abundance using pan macrophage markers (CD11b/CD68) and anti-inflammatory markers (CD206/CD163) following exercise training in …

The Effects Of Dietary Nitrate And Vitamin C On Endothelial Function And Oxidative Stress Biomarkers, Reem Basaqr

Theses and Dissertations--Pharmacology and Nutritional Sciences

Background: Endothelial dysfunction is associated with a decline in the vasodilator nitric oxide (NO) and presents alongside other cardiovascular risk factors in the early stages of atherosclerosis. Independently, inorganic nitrate and vitamin C supplementation have shown promise in providing some restoration of NO bioavailability, reduced oxidative stress, and improvements in endothelial function. Some preliminary evidence has suggested that vitamin C may augment the reduction of nitrite to further liberate NO and improve cardiovascular health. However, co-supplementation has not been adequately studied. Our objective was to compare the effect of inorganic nitrate in the form of concentrated beetroot juice (CBJ) with …

Functional Impact Of Angiotensinogen Specific Domains On Angiotensin Ii-Mediated Functions, Chia-Hua Wu

Theses and Dissertations--Pharmacology and Nutritional Sciences

Angiotensinogen (AGT) is the only substrate for all angiotensin peptides in the renin angiotensin system (RAS). Cleavage of AGT by renin is a rate-limiting step of angiotensin peptides productions in the RAS and regulates angiotensin peptides-associated pathophysiological functions. Only ten N-terminal residues are cleaved by renin and the functions of remaining part of AGT protein, which is called des(angiotensin I)AGT, remain unclear. Despite of pivotal roles of AGT in the RAS, studies related to how AGT is metabolized and how des(angiotensin I)AGT regulates AGT functions or AngII-mediated functions are limited.

Renin cleavage of AGT shows species specificity. It has been …

Divergence In Neuronal Calcium Dysregulation In Brain Aging And Animal Models Of Ad, Adam Ghoweri

Theses and Dissertations--Pharmacology and Nutritional Sciences

Neuronal calcium dysregulation first garnered attention during the mid-1980’s as a key factor in brain aging, which led to the formulation of the Ca²⁺ hypothesis of brain aging and dementia. Indeed, many Ca²⁺-dependent cellular processes that change with age, including an increase in the afterhyperpolarization, a decrease in long-term potentiation, an increased susceptibility to long-term depression, and a reduction in short-term synaptic plasticity, have been identified. It was later determined that increased intracellular Ca²⁺ with age was due to increased Ca²⁺ channel density, elevated release from intracellular Ca²⁺ stores, and decreased Ca²⁺ buffering …

Role Of Pancreatic Amylin In Alzheimer’S And Brain Microvascular Pathologies, Han Gia Ly

Theses and Dissertations--Pharmacology and Nutritional Sciences

Alzheimer disease (AD) and cerebral vascular disease (CVD) are common causes of impaired cognition and behavior in humans. Epidemiological studies have shown that AD and CVD development and progression associated with metabolic risk factors including type 2 diabetes (T2D). However, the underlying molecular mechanisms remain elusive, which hampers the development of treatment and prevention strategies. Research results from our laboratory and others have shown that amylin, a hormone secreted by the pancreas and involved in glucose homeostasis, induces small-vessel-type pathologies and modulates amyloid composition in both familial (genetically predisposed) and sporadic forms of AD. The results indicate amylin as a …

Apoe As A Metabolic Regulator In Humans, Mice, And Astrocytes, Brandon C. Farmer

Theses and Dissertations--Physiology

Altered metabolic pathways appear to play central roles in the pathophysiology of late-onset Alzheimer’s disease (AD). Carrier status of the E4 allele of the APOE gene is the strongest genetic risk factor for late-onset AD, and increasing evidence suggests that E4 carriers may be at an increased risk for neurodegeneration based on inherent metabolic impairments. A new appreciation is forming for the role of APOE in cerebral metabolism, and how nutritional factors may impact this role. In chapter 1, the literature on nutritional interventions in E4 carriers aimed at mitigating disease risk is reviewed. Studies investigating the mechanism by which …

Striated Muscle Specific Ribosomal Protein L3-Like: Effect Of Knockout On Cardiac Function And Protein Translation, Laura P. Brown

Theses and Dissertations--Physiology

Ribosomes are the molecular machinery of the cell that catalyzes synthesis of peptides from amino acids. The eukaryotic ribosome is made up of four strands of ribosomal RNA (rRNA) and ~80 ribosomal proteins. While many tissues routinely exhibit variations of ribosomal protein stoichiometry, tissue specific ribosomal proteins are rare. The ribosomal protein with the highest tissue specificity of any ribosomal protein is found in striated muscle, ribosomal protein L3-like (RPL3L). Other than its tissue specificity, association with atrial fibrillation, and chromosomal location, there is little known about the function of RPL3L. However, its ubiquitously expressed paralog, RPL3, has been well …

Involvement Of The Renin Angiotensin System In Marfan Syndrome Associated Thoracic Aortic Aneurysms, Jeff Zheying Chen

Theses and Dissertations--Physiology

Thoracic aortic aneurysms (TAAs) are clinically-silent dilations of the aorta which greatly increase the risk of aortic rupture, a condition with 50-90% mortality. Marfan syndrome (MFS) is caused by mutations in fibrillin-1 (FBN1) and is associated with TAAs. Due to an absence of validated and effective pharmacologic therapies to prevent or reverse TAA, most MFS patients require surgical aortic repair. Understanding MFS associated TAA pathogenesis would direct development of new pharmacologic therapies. Previous research has implicated the renin angiotensin system in TAA. In both males and females, angiotensinogen (AGT) is cleaved serially to generate the main effector peptide angiotensin II …

Remodeling In The Actin Core Of The Auditory Hair Cell Stereocilia As A Novel Component Of Temporary Noise-Induced Hearing Loss, Jonathan Michael Grossheim

Theses and Dissertations--Physiology

The rigid, paracrystalline actin core of auditory hair cell stereocilia is extremely stable and after initial formation must persist for the life of the cell to preserve hearing in mammals. In healthy hair cells, turnover of actin molecules occurs only in a small region near the tips of stereocilia, while the actin filaments of the shaft are stable. For decades damage to the actin core of stereocilia from acoustic trauma has only been attributed to cases of permanent noise-induced hearing loss. Here, we show that repairable actin core damage occurs in temporary noise-induced hearing loss from moderate acoustic trauma.

We …

Ceramide-Enriched Extracellular Vesicles: A Role In Enhancing Amyloid-Beta Neurotoxicity And Mitochondrial Damage In Alzheimer’S Disease, Ahmed Elsherbini

Theses and Dissertations--Physiology

Alzheimer’s disease (AD) is an age-dependent, progressive, neurodegenerative disorder that is characterized clinically by the impairment of cognitive functions concomitant with behavioral and personality changes. AD is associated with distinct pathological hallmarks, namely, intracellular neurofibrillary tangles comprised of hyperphosphorylated tau protein, extracellular amyloid beta (Aβ) plaques, and marked brain atrophy. Besides their main role as the core component of amyloid plaques, oligomeric Aβ have been shown to be neurotoxic. The exact mechanism of Aβ neurotoxicity is yet to be elucidated.

Recently, a pathogenic function of small extracellular vesicles- also known as exosomes- has been proposed, suggesting that exosomes can transfer …

Apparel Sizing And Fit For Girls: Variation Of Select Companies, And Parent Opinions, Peggy Sowah, Ashia

Theses and Dissertations--Retailing and Tourism Management

The act of shopping for girl's clothes is a delight of most parents. It ignites the pleasure of being a parent. However, many parents and their girls have experienced the frustration of inconsistent sizing and fit of their girl's clothes across brands. The purpose of this study was to understand the sizing and fit problems of girls ages 7-12 and to evaluate how brands utilize the current sizing standards. A structured questionnaire was used to collect data from a population of 150 (N=150) female parents. A survey was administered to help gain a better understanding and assess parent opinion of …

Pathogenicity, Toxigenic Potential, And Genomics Of Fusarium Graminearum And F. Meridionale Causing Ear And Stalk Rot Of Maize, Franklin Jackson Machado

Theses and Dissertations--Plant Pathology

Gibberella ear (GER) and stalk rot (GSR) diseases of maize in Brazil are caused mainly by Fusarium meridionale, a species belonging to the Fusarium graminearum species complex (FGSC). Another species within this complex, F. graminearum sensu stricto (hereafter F. graminearum), is second in importance on maize, but is the most common species found causing Fusarium Head Blight disease of wheat in Brazil. The latter species is the predominant cause of GER and GSR in North America, where F. meridionale has not been found thus far. In this dissertation I undertook a comparative analysis of pathogenic, saprophytic, toxigenic and …

Evaluation Of Rhodococcus Equi Susceptibility To Silver Nanoparticle Antimicrobials, Elizabeth Boudaher

Theses and Dissertations--Veterinary Science

Rhodococcus equi is a significant cause of pneumonia in foals and immunocompromised humans. Antimicrobial resistance among R. equi isolates has developed as a consequence of inappropriate stewardship and bacterial evolution, leading to an increased rate of treatment failures that typically result in foal fatality. In the current study, we evaluated the efficacy of antimicrobial silver nanoparticle (AgNP) complexes in controlling R. equi growth. Previous studies characterizing AgNP-induced antibacterial effects in other Gram-positive pathogens led us to hypothesize that silver nanoparticle antimicrobials impact R. equi viability and intracellular replication. We therefore investigated the effect of silver nanoparticle complexes on R. equi …

Donor Age Effects On The Proliferative And Chondrogenic/Osteogenic Differentiation Performance Of Equine Bone Marrow- And Adipose Tissue Derived Mesenchymal Stem Cells In Culture, Jasmin Bagge

Theses and Dissertations--Veterinary Science

Orthopedic injuries are a major cause of lameness and morbidity in horses. Bone marrow (BM)- and adipose tissue (AT) derived mesenchymal stem cells (MSCs) have shown potential to facilitate the repair of orthopedic injuries and are being used increasingly in veterinary clinics. Presently, the use of MSCs as a therapy for equine patients is most commonly applied as autologous transplants, using BM- and AT-MSCs harvested from the patient shortly after the time of injury. Cell-based therapies are therefore delayed to enable primary cell numbers to be expanded in culture. Of concern, however, are human and rodent studies that have shown …

Host-Parasite Interaction In Horses: Mucosal Responses To Naturally Acquired Cyathostomin Infections And Anthelmintic Treatment, Ashley Elaine Steuer

Theses and Dissertations--Veterinary Science

Cyathostomins are ubiquitous parasites in equids. In rare cases, cyathostomins lead to a generalized typhlocolitis and death. In healthy horses, local reactions are noted to the mucosal larvae; however, the mechanisms and importance of these reactions have not been elucidated. It has been hypothesized that anthelmintics can alter these reactions. Currently, three drug classes are approved for use in horses against cyathostomins; while all products target the adults, only two products are labeled as larvicidal. Adulticidal therapy is implicated in triggering the typhlocolitis, however, current evidence is contradictory. There is also conjecture that the larvicidal drugs can increase the risk …

Comparative Chondrogenesis Of Interzone And Anlagen Cells In Equine Skeletal Development, Chanhee Mok

Theses and Dissertations--Veterinary Science

At the presumptive sites of future synovial joints during mammalian skeletogenesis, articular cartilage develops from interzone located between the cartilaginous anlagen of bones. Thus, two types of cartilaginous tissues differentiate in close proximity. While anlagen cartilage is transient, progressing through endochondral ossification to form bones, articular cartilage is stable and functions throughout life to facilitate both low friction movement and load distribution. Despite important life-long functional properties, articular cartilage has a very limited intrinsic ability to repair structural defects. On the other hand, structural lesions in bones generally heal well by forming a cartilaginous callus and recapitulating endochondral ossification to …

Effects Of Thinning Regimes On Genetic Variation Of White Oak (Quercus Alba L.) In Upland Oak Forests Of Eastern Kentucky, Rachel Gayle Thunder

Theses and Dissertations--Forestry and Natural Resources

This research assesses the effects of silvicultural thinnings, varying in residual basal area and number of thinnings, on genetic diversity and relatedness of white oak (Quercus alba L.). The objectives were to (1) develop microsatellite DNA markers (simple sequence repeats, SSRs) for assessing the genetic diversity of white oak and (2) determine if thinnings significantly change the degree of diversity and relatedness in white oak stands. For objective 1, 84 primer pairs from previously predicted genomic SSRs of white oak were evaluated for consistent PCR amplification and polymorphism. Twenty of the 84 primer pairs amplified consistently and were confirmed …

Ecosystem Of Bagged Grain Stored Under Naturally Ventilated Warehouse: Analysis And Modelling, Michael Ayodele Omodara

Theses and Dissertations--Biosystems and Agricultural Engineering

Grain in Africa and indeed most developing parts of the world are stored in polypropylene or jute bags arranged in stacks of varied dimensions in naturally ventilated warehouses. This practice is, however, associated with high postharvest losses due to poor temperature and moisture management during storage. This constitutes a major economic and food security challenge in these countries. Therefore, this study characterizes changes in moisture content and temperature occurring in a stack of bagged corn by determining the permeability of bag materials that influence moisture transfer and developing a mathematical model of heat and mass transfer which incorporates the unique …

Effects Of Watershed Disturbances And River-Tributary Confluences On Sedimentation Dynamics In The Upper Ohio River Basin, Ciara Pickering

Theses and Dissertations--Biosystems and Agricultural Engineering

Harmful algal blooms (HABs) are of increasing concern in the Ohio River Basin. Fine sediment dynamics in riverine environments are increasingly recognized to play important roles in proliferation and toxicity of Microcystis blooms. Further, the fate of sediment at confluences of tributaries and the main river system are important zones for sediment retention and transient storage. The objective of this study was to improve understanding of watershed sediment loading dynamics and backwater inundation influencing sedimentation within confluence watersheds. The study site is the Fourpole Creek watershed in Huntington, WV which is a disturbed forested watershed impacted by a backwater confluence …

Aggregation Behavior In The Bed Bug, Cimex Lectularius L., Paul D. Baker

Theses and Dissertations--Entomology

The bed bug, Cimex lectularius L., is a common household pest that feeds on the blood of its human hosts. Unlike many other hematophagic arthropods, bed bugs have not demonstrated the ability to vector disease; yet its presence in a household often leads to fear and anxiety amongst its human host victims. Bed bugs spend the majority of their time aggregating in enclosed and hidden locations, making it difficult to detect and eradicate them. One of the significant mediators of aggregation behavior is an aggregation pheromone. The pheromone has been identified to be six chemical compounds, five volatile compounds that …

Management Of Sugarcane Aphid (Melanaphis Sacchari) Using Biological And Cultural Tactics In Kentucky, Nathan Harriman Mercer

Theses and Dissertations--Entomology

In 2013, a new aphid pest of sorghum, the sugarcane aphid Melanaphis sacchari Zehntner (Hemiptera: Aphididae), was found in the southern US, and caused significant yield loss in sorghum. Since then, M. sacchari has spread to most of the sorghum growing regions. Unmanaged populations can cause complete crop loss in grain, forage and sweet sorghum. M. sacchari cannot survive winters without a live plant tissue and must recolonize much of its pest range annually. Sweet sorghum (Sorghum bicolor) is an important crop for many growers in Kentucky, producing $16-25 million a year from its syrup. Biological control of …