Digital Commons Network^™

Neuropilin In The Vascular System: Mechanistic Basis Of Angiogenesis, Hou-Fu Guo

Theses and Dissertations--Molecular and Cellular Biochemistry

The vascular system is critical for maintaining homeostasis in all vertebrates. Structural studies of Neuropilin (Nrp), an essential angiogenic receptor, have defined its role in regulating angiogenesis, the formation of new vessels from the existing vasculature. Utilizing biochemical and biophysical tools we describe the ability of Nrp to function as a co-receptor for the VEGFR receptor tyrosine kinase. Two families of Nrp-1 ligands, Vascular Endothelial Growth Factor A (VEGF-A) and Semaphorin3F (Sema3F), physically compete for binding to the Nrp-1 b1 domain, and have opposite roles. VEGF-A is a potent pro-angiogenic cytokine while Sema3F is an angiogenesis inhibitor. Using coupled structural …

Characterization Of Jabba, A Ricin-Resistant Mutant Of Leishmania Donovani, Megan Rhea Phillips

Theses and Dissertations--Molecular and Cellular Biochemistry

The abundant cell-surface lipophosphoglycan (LPG) of Leishmania parasites plays a central role throughout the eukaryote’s life cycle. A number of LPG-defective mutants and their complementing genes have been isolated and have proven invaluable in assessing the importance of LPG and related glycoconjugates in parasite virulence. While ricin agglutination selection protocols frequently result in lpg- mutants, one L. donovani variant we isolated, named JABBA, was found to be lpg+. Procyclic (logarithmic) JABBA expresses significant amounts of a large-sized LPG, larger than observed from procyclic wild-type but similar in size to LPG from wild-type from metacyclic (stationary) phase.

Structural analysis of …

Regulation Of Glucose Homeostasis By The Phlpp1 Phosphatase, Kara L. Larson

Theses and Dissertations--Molecular and Cellular Biochemistry

Type 2 diabetes mellitus is a metabolic disease that affects one in ten people in the United States. It is caused by a combination of genetics and lifestyle factors. Disease progression begins with insulin resistance in peripheral tissues followed by pancreatic beta-cell failure. The mechanisms behind disease progression are not completely understood. PH domain leucine rich repeat protein phosphatase 1 (PHLPP1) is a known regulator of Akt and other members of the AGC kinase family. Akt has been established to play a role in numerous metabolic signaling pathways, including insulin action. It is hypothesized that as a regulator of Akt, …

Molecular Mechanisms Of Neuropilin-Ligand Binding, Matthew W. Parker

Theses and Dissertations--Molecular and Cellular Biochemistry

Neuropilin (Nrp) is an essential cell surface receptor with dual functionality in the cardiovascular and nervous systems. The first identified Nrp-ligand family was the Semaphorin-3 (Sema3) family of axon repulsion molecules. Subsequently, Nrp was found to serve as a receptor for the vascular endothelial growth factor (VEGF) family of pro-angiogenic cytokines. In addition to its physiological role, VEGF signaling via Nrp directly contributes to cancer stemness, growth, and metastasis. Thus, the Nrp/VEGF signaling axis is a promising anti-cancer therapeutic target. Interestingly, it has recently been shown that Sema3 and VEGF are functionally opposed to one another, with Sema3 possessing potent …

Leptin Resistance Induced Obesity And Diabetes Promote Neuropathological Changes In The Aging Brain, Thomas Platt

Theses and Dissertations--Molecular and Cellular Biochemistry

The aging brain is prone to the development of pathology and dementia. With a rapidly growing elderly population diagnoses of neurodegenerative diseases, such as Alzheimer’s disease (AD), frontotemporal dementia (FTD), and Parkinson’s disease are on the rise. Additionally, diabetes and obesity are linked to an increased risk of dementia. The convergence of this increasingly aged population with the obesity and diabetes epidemic give rise to new concerns regarding the future of prevention and treatment of neurodegenerative diseases. Our lab has previously shown that leptin, an adipokine involved in signaling satiety to the hypothalamus, can modulate the generation of the amyloid …

Material Tensors And Pseudotensors Of Weakly-Textured Polycrystals With Orientation Measure Defined On The Orthogonal Group, Wenwen Du

Theses and Dissertations--Mathematics

Material properties of polycrystalline aggregates should manifest the influence of crystallographic texture as defined by the orientation distribution function (ODF). A representation theorem on material tensors of weakly-textured polycrystals was established by Man and Huang (2012), by which a given material tensor can be expressed as a linear combination of an orthonormal set of irreducible basis tensors, with the components given explicitly in terms of texture coefficients and a number of undetermined material parameters. Man and Huang's theorem is based on the classical assumption in texture analysis that ODFs are defined on the rotation group SO(3), which strictly speaking makes …

Targeted Knockout Of Beclin-1 Reveals An Essential Function In Ovary And Testis, Thomas R. Gawriluk

Theses and Dissertations--Biology

An estimated 12% of couples worldwide are infertile. The contributing factor is approximately equal between men and women with nearly 25% diagnosed as idiopathic. Despite the increasing numbers of couples seeking assistance from infertility clinics, few molecular mechanisms have been identified for treatment. Autophagy is an evolutionarily conserved cellular process for bulk degradation and recycling of cytosolic components through the lysosome to maintain homeostasis. Several studies have observed increased levels of autophagy during ovarian folliculogenesis and gonadal steroidogenesis; however, no genetic studies to determine the significance of autophagy exist.

To investigate the function of autophagy in the ovary and testis, …

Dimensions And Validation Of Perceived Message Sensation Value Scale For Print Messages, Lisanne F. M. Grant

Theses and Dissertations--Communication

The purpose of this research project was to develop a reliable and valid scale to assess the perceived message sensation value (PMSV) of print messages. The goal of this project was accomplished by conducting two studies. Study one involved collecting 397 undergraduate students’ responses to one high and one low sensation value anti-smoking message, while for study two, 284 undergraduate students’ responses to one high and one low sensation value anti-crystal meth message were collected. The results of the studies highlighted that the PMSV of a print message can be assessed using three dimensions (emotional arousal, novelty, and dramatic impact) …

Reference Compensation For Localized Surface-Plasmon Resonance Sensors, Neha Nehru

Theses and Dissertations--Electrical and Computer Engineering

Noble metal nanoparticles supporting localized surface plasmon resonances (LSPR) have been extensively investigated for label free detection of various biological and chemical interactions. When compared to other optical sensing techniques, LSPR sensors offer label-free detection of biomolecular interactions in localized sensing volume solutions. However, these sensors also suffer from a major disadvantage – LSPR sensors remain highly susceptible to interference because they respond to both solution refractive index change and non-specific binding as well as specific binding of the target analyte. These interactions can severely compromise the measurement of the target analyte in a complex unknown media and hence limit …

Volume And Surface Integral Equations For Solving Forward And Inverse Scattering Problems, Xiande Cao

Theses and Dissertations--Electrical and Computer Engineering

In this dissertation, a hybrid volume and surface integral equation is used to solve scattering problems. It is implemented with RWG basis on the surface and the edge basis in the volume. Numerical results shows the correctness of the hybrid VSIE in inhomogeneous medium. The MLFMM method is also implemented for the new VSIEs.

Further more, a synthetic apature radar imaging method is used in a 2D microwave imaging for complex objects. With the mono-static and bi-static interpolation scheme, a 2D FFT is applied for the imaging with the data simulated with VSIE method. Then we apply a background cancelling …

Proposed Middleware Solution For Resource-Constrained Distributed Embedded Networks, Jason T. Rexroat

Theses and Dissertations--Electrical and Computer Engineering

The explosion in processing power of embedded systems has enabled distributed embedded networks to perform more complicated tasks. Middleware are sets of encapsulations of common and network/operating system-specific functionality into generic, reusable frameworks to manage such distributed networks. This thesis will survey and categorize popular middleware implementations into three adapted layers: host-infrastructure, distribution, and common services. This thesis will then apply a quantitative approach to grading and proposing a single middleware solution from all layers for two target platforms: CubeSats and autonomous unmanned aerial vehicles (UAVs). CubeSats are 10x10x10cm nanosatellites that are popular university-level space missions, and impose power and …

A New Design Of Dc-Dc Converter For Capacitive Deionization Process, Zhiao Li

Theses and Dissertations--Electrical and Computer Engineering

The shortage of clean water has become a significant global problem, and capacitive deionization (CDI) is a technology that can be used to help relieve the problem. A Ćuk converter system that can recover energy from CDI cells is described. This converter transfers energy between two CDI cells when a cell is in its desorption period, allowing energy that would otherwise be lost to be recovered and improving overall system efficiency. In order to control the states of the MOSFET switches in the converter, a self boost charge pump is used. In this way, the microcontroller can control system duty …

A Multi-Physics Computational Approach To Simulating Thz Photoconductive Antennas With Comparison To Measured Data And Fabrication Of Samples, Darren Ray Boyd

Theses and Dissertations--Electrical and Computer Engineering

The frequency demands of radiating systems are moving into the terahertz band with potential applications that include sensing, imaging, and extremely broadband communication. One commonly used method for generating and detecting terahertz waves is to excite a voltage-biased photoconductive antenna with an extremely short laser pulse. The pulsed laser generates charge carriers in a photoconductive substrate which are swept onto the metallic antenna traces to produce an electric current that radiates or detects a terahertz band signal. Therefore, analysis of a photoconductive antenna requires simultaneous solutions of both semiconductor physics equations (including drift-diffusion and continuity relations) and Maxwell’s equations. A …

Tobacco Treatment In College Students, Teresa H. Huber

DNP Projects

This study was conducted in a southeastern University to determine tobacco use status in a population of university students, student intention to quit, treatment options, use of student health service, and student’s degree of support of a tobacco-free policy. A major implication for practice is the need for college health providers to screen all students utilizing the USPHS Guidelines, as even light smokers may be vulnerable to nicotine addiction. However, the study found that a high proportion of the smokers were nondaily smokers who do not consider themselves as smokers and the vast majority of those were undergraduates. Thus, college …

Tall Fescue Ergovaline Concentration Based On Sample Handling And Storage Method, Krista La Moen Lea

Theses and Dissertations--Plant and Soil Sciences

Ergovaline is produced by the endophyte Neotyphodium coenophialum (Morgan-Jones and Gams) in tall fescue (Schedonorus arundinacea (Schreb.) Dumort. = Festuca arundinacea Schreb.) and is blamed for a multitude of costly livestock disorders. Testing of pastures is common in both research and on farm situations. Since ergovaline is known to be unstable and affected by many variables, the objective of this study was to determine the effect of sample handling and storage on the stability of this compound. Homogeneous milled tall fescue sub-samples were analyzed for ergovaline concentration using HPLC after a range of sample handling procedures or storage. Ergovaline …

Field-Scale Water And Solute Transport, Yang Yang

Theses and Dissertations--Plant and Soil Sciences

Spatial variability of soil properties complicates the understanding of water and solute transport at the field scale. This study evaluated the impact of land use, soil surface roughness, and rainfall characteristics on water transport and Br^- leaching under field conditions by means of a new experimental design employing scale-dependent treatment distribution. On a transect with two land use systems, i.e., cropland and grassland, rainfall intensity and the time delay between Br^- application and subsequent rainfall were arranged in a periodically repetitive pattern at two different scales. Both scales were distinct from the scale of surface roughness as described …

Bacteria In Bioethanol Fermentations, Qing Li

Theses and Dissertations--Plant and Soil Sciences

To gain a better understanding of contaminating bacteria in bioethanol industry, we profiled the bacterial community structure in corn-based bioethanol fermentations and evaluated its correlation to environmental variables. Twenty-three batches of corn-mash sample were collected from six bioethanol facilities. The V4 region of the collective bacterial 16S rRNA genes was analyzed by Illumina Miseq sequencing to investigate the bacterial community structure. Non-metric multidimensional scaling (NMDS) ordination plots were constructed to visualize bacterial community structure groupings among different samples, as well as the effects of multiple environmental variables on community structure variation. Our results suggest that bacterial community structure is facility-specific, …

Stability Studies Of Membrane Proteins, Cui Ye

Theses and Dissertations--Chemistry

The World Health Organization has identified antimicrobial resistance as one of the top three threats to human health. Gram-negative bacteria such as Escherichia coli are intrinsically more resistant to antimicrobials. There are very few drugs either on the market or in the pharmaceutical pipeline targeting Gram-negative pathogens. Two mechanisms, the protection of the outer membrane and the active efflux by the multidrug transporters, play important roles in conferring multidrug resistance to Gram-negative bacteria. My work focuses on two main directions, each aligning with one of the known multidrug resistance mechanisms.

The first direction of my research is in the area …

Salen Aluminum Compounds In The Dealkylation And Detection Of Organophosphates, Rahul R. Butala

Theses and Dissertations--Chemistry

The focus of this dissertation is the use of aluminum Schiff base compounds, Salen(^tBu)AlBr (SAB), in the dealkylation and detection of organophosphates (OPs). Three SAB compounds, Salen(^tBu)AlBr (1), Salpen(^tBu)AlBr (2), and Salophen(^tBu)AlBr (3) were used to dealkylate a variety of trialkyl OPs. These reactions lead to unique organic-soluble aluminum phosphate compounds containing six-coordinate aluminum. Examples include [salen(^tBu)AlOP(O)(OCH₃)₂]_n (4), [salen(^tBu)AlOP(O)(OCH₂CH₃)₂]_n (5), [salen(^tBu)AlOP(O)(OPh)₂]_{n …}

The Development And Biocompatibility Of Low Temperature Co-Fired Ceramic (Ltcc) For Microfluidic And Biosensor Applications, Jin Luo

Theses and Dissertations--Chemical and Materials Engineering

Low temperature co-fired ceramic (LTCC) electronic packaging materials are applied for their electrical and mechanical properties, high reliability, chemical stability and ease of fabrication. Three dimensional features can also be prepared allowing integration of microfluidic channels and cavities inside LTCC modules. Mechanical, optical, electrical, microfluidic functions have been realized in single LTCC modules. For these reasons LTCC is attractive for biomedical microfluidics and Lab-on-a-Chip systems. However, commercial LTCC systems, optimized for microelectrics applications, have unknown cytocompatibility, and are not compatible with common surface functionalization chemistries.

The first goal of this work is to develop biocompatible LTCC materials for biomedical applications. …

Functionalized Membranes For Environmental Remediation And Selective Separation, Li Xiao

Theses and Dissertations--Chemical and Materials Engineering

Membrane process including microfiltration (MF), ultrafiltration (UF), nanofiltration (NF) and reverse osmosis (RO) have provided numerous successful applications ranging from drinking water purification, wastewater treatment, to material recovery. The addition of functional moiety in the membranes pores allows such membranes to be used in challenging areas including tunable separations, toxic metal capture, and catalysis. In this work, polyvinylidene fluoride (PVDF) MF membrane was functionalized with temperature responsive (poly(N-isopropylacrylamide), PNIPAAm) and pH responsive (polyacrylic acid, PAA) polymers. It’s revealed that the permeation of various molecules (water, salt and dextran) through the membrane can be thermally or pH controlled. The introduction of …

Nanometer-Scale Membrane Electrode Systems For Active Protein Separation, Enzyme Immobilization And Cellular Electroporation, Zhiqiang Chen

Theses and Dissertations--Chemical and Materials Engineering

Automated and continuous processes are the future trends in downstream protein purification. A functionalized nanometer-scale membrane electrode system, mimicking the function of cell wall transporters, can selectively capture genetically modified proteins and subsequently pump them through the system under programmed voltage pulses. Numerical study of the two-step pulse pumping cycles coupled with experimental His-GFP releasing study reveals the optimal 14s/1s pumping/repel pulse pumping condition at 10 mM bulk imidazole concentration in the permeate side. A separation factor for GFP: BSA of 9.7 was achieved with observed GFP electrophoretic mobility of 3.1×10^-6 cm² s^-1 V^-1 at 10 …

Layer-By-Layer Assemblies For Membrane-Based Enzymatic Catalysis, Andrew R. Tomaino

Theses and Dissertations--Chemical and Materials Engineering

While considerable progress has been made towards understanding the effect that membrane-based layer-by-layer (LbL) immobilizations have on the activity and stability of enzymatic catalysis, detailed work is required in order to fundamentally quantify and optimize the functionalization and operating conditions that define these properties. This work aims to probe deeper into the nature of transport mechanisms by use of pressure-induced, flow-driven enzymatic catalysis of LbL-functionalized hydrophilized poly(vinyldiene) (PVDF)-poly(acrylic acid) (PAA)-poly(allylamine hydrochloride) (PAH)-glucose oxidase (GOx) membranes. These membranes were coupled in a sealed series following cellulose acetate (CA) membranes for the elimination of product accumulation within the feed-side solution during operation. …

Temperature-Dependent Tunable Photoluminescence Properties Of Carbon Nanodots Derived From Polyethylene Glycol, Sin Hea Yeom

Theses and Dissertations--Chemistry

Fluorescent carbon dots (C-dots) are well known for their low cell-cytotoxicity, biocompatibility, low preparation cost, excitation dependent photoluminescence, and excellent photostability. Typically, raw C-dots have low quantum efficiency and thus researchers have been utilizing biocompatible polymers such as polyethylene glycol (PEG) as a passivation agent in order to increase fluorescence signal. In this work, we report fluorescent self-passivated carbon nanodots (CNDs) synthesized from PEG by using it as a carbon source as well as a passivating agent. Importantly, the addition of graphene quantum dots (GQDs) during the synthesis of self-passivated CNDs can tune photoluminescence property. The results of bioimaging and …

The Differences Between Iron And Iron-Substituted Manganese Superoxide Dismutase With Respect To Hydrogen Peroxide Treatment, Jianing Wang

Theses and Dissertations--Chemistry

Iron-substituted manganese superoxide dismutase (Fe(Mn)SOD) was produced using an in vivo preparation method. It’s an inactive enzyme in catalyzing superoxide radical dismutation owing to the mis-incorporation of Fe in the active site evolved to use Mn. To investigate the possible toxicity of human Fe(Mn)SOD proposed by Yamakura, we studied the properties of Fe(Mn)SOD upon H₂O₂ treatment and compared to that of FeSOD. It’s found that the responses to H₂O₂ treatment were different, including the changes of optical spectra, variations of active site coordination and secondary structures. Fe³⁺ reduction was not observed in Fe(Mn)SOD …

Addressing Public Health Risks Of Persistent Pollutants Through Nutritional Modulation And Biomimetic Nanocomposite Remediation Platforms, Bradley J. Newsome

Theses and Dissertations--Chemistry

Due to their relative chemical stability and ubiquity in the environment, chlorinated organic contaminants such as polychlorinated biphenyls (PCBs) pose significant health risks and enduring remediation challenges. Engineered nanoparticles (NPs) provide a novel platform for sensing/remediation of these toxicants, in addition to the growing use of NPs in many industrial and biomedical applications, but there remains concern for their potential long-term health effects. Research highlighted herein also represents a transdisciplinary approach to address human health challenges associated with exposure to PCBs and NPs. The objectives of this dissertation research are two-fold, 1) to develop effective methods for capture/sensing and remediation …

Sexting And Freedom Of Expression: A Comparative Approach, Joanne Sweeny

Kentucky Law Journal

No abstract provided.

"Hobby-Lobby"-Ing For Religious Freedom: Crafting The Religious Employer Exemption To The Ppaca, Emily Pitt Mattingly

Kentucky Law Journal

No abstract provided.

Promising Protection: 911 Call Records As Foundation For Family Violence Intervention, Linda L. Bryant, James G. Dwyer

Kentucky Law Journal

No abstract provided.

Giving Meaning To "Meaningful Access" In Medicaid Managed Care, Mary Crossley

Kentucky Law Journal

No abstract provided.