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Transfer Of Antibiotic Resistance In Enterococcus Faecalis. Modeling And Computational Study, Vu Tran

Open Access Dissertations

Bacteria of the genus Enterococcus, commonly found in the intestinal tract, are the main cause of antibiotic-resistant infections that are acquired in hospitals[1], [2]. Donor cells that contain plasmid pCF10 have the ability to resist to antibiotics and are capable of transferring this plasmid to recipient cells. This transfer occurs via a rapid horizontal inducible conjugation regulated by peptide-mediated cell-cell signaling molecules (quorum sensing), known as cCF10 and iCF10. This quorum sensing system functions by producing low levels of an inducing substance that accumulates in the environments until a threshold is reached, at which point there is a change in …

Quality And Nutritional Impacts Of Extrution On Pearl Millet And Nutrient Dense Native Plant Blends, Cheikh Ndiaye

Open Access Dissertations

Significant efforts have been placed on the development of strategies to address micronutrient deficiencies in Sub-Saharan parts of Africa. Improving the nutritional value of staple foods, including cereals, is a key component of such strategies as traditional cereals such as millet and sorghum are mostly consumed in these areas. Of micronutrient deficiencies, iron, zinc and vitamin A are most critical, and mostly deficient in staple cereal foods. One option to improve the nutrient density of cereal foods is to leverage natural micronutrient dense plant materials that exist locally, and can be formulated into cereals products. Such products can be combined …

Synthesis Of Spliceostatin E And Decytospolide A And B And Progress Toward The Synthesis Of Thailanstatin A, Anne M. Veitschegger

Open Access Dissertations

The first stereoselective total synthesis of spliceostatin E has been accomplished. The left hand δ-lactone subunit was constructed from commercially available (R)-glycidyl alcohol through a ring-closing metathesis as the key reaction. The central-functionalized tetrahydropyran ring was synthesized as done in the synthesis of spliceostatin A. An olefin cross-metathesis of the δ-lactone and the central tetrahydropyran ring provided spliceostatin E. Spliceostatin E was originally reported to exhibit potent antitumor activity, however, our biological evaluation of synthetic spliceostatin E revealed that it did not inhibit in vitro spicing and did not impact speckle morphology in cells. A stereoselective total synthesis of thailanstatin …

Plant Mediated Effects On Tritrophic Interactions In The Solanaceae-Hornworm System, Michael A. Garvey

Open Access Dissertations

Top-down pressure from parasites is thought to be a key driver in herbivore diet breath, but studies investigating the evolution of food plant shifts as a defense against natural enemies in the environment are still lacking in the literature. I examined how plants alter insect-enemy interactions for a specialist herbivore utilizing solanaceous food plants, Manduca sexta (the tobacco hornworm) and the parasitoid wasp, Cotesia congregata, as a model. In this study, I documented parasite infections in a field population of M. sexta, and then investigated from an eco-immunological perspective how plant toxins influence susceptibility to parasites in order to explain …

Strategies To Create Interfacial Patterning And Epitaxial Architectures Using Controllable Anisotropic Wetting At Scales <10nm On Polyfunctional Noncovalent Ligand Layers, Shi Wah Choong

Open Access Dissertations

Chemical orthogonality at sub-10 nm is important in synthetic material applications. Synthetic materials require surfaces with two very different types of chemistry. For instance, nanoelectronics require repeating units of metal and oxide at 5- and 7-nm length scales.1-3 In polymer solar cells, the capability to cause n-type and p-type blocks to phase segregate at length scales < 10 nm would provide more efficient charge transport.4-6 Increasingly high resolution patterning has been achieved using lithographic techniques to manufacture devices with features as small as 14 nm and in some cases smaller.7-11 It is extremely difficult to precisely engineer and fabricate 3D interfaces with features less than 10 nm and high cost is associated with it.12-14 However, nature routinely addresses a similar challenge in the context of lipid bilayer, which has a thickness of about 6 nm. Lipid bilayer is made of phospholipids with an alternating hydrophilic and hydrophobic pattern to control the flow of water, ions and other small molecules across the cell membrane. The orthogonality of the lipid bilayer is hidden in the membrane core along the z-axis but for applications in nanoelectronics and organic photovoltaics, both chemical functionalities need to be displayed on the surface. My dissertation research focused on using bio-inspired molecules to create precisely patterned layered materials with chemical orthogonality of ~6 nm, and utilizing these noncovalent monolayers to achieve molecular-scale wetting control, to create nanometer-thick film along the rows of headgroups using polar liquid as well as utilizing these polyfunctional layered materials to template epitaxial nanocrystals of small organic molecules. In this dissertation work, I have created nanoplates with thickness of ca. 1 nm as well as nanorods with length ~21 nm and width ~6 nm, which is similar to the lamellar width of the templating monolayers. These nanostructures adopt epitaxial alignment along the lamellae of the amphiphilic monolayers. My thesis work shows potential strategies useful for precise interfacial patterning for synthetic material applications at very short length scales.

Multidimensional Nonlinear Optical Imaging, Fengyuan Deng

Open Access Dissertations

The work in this dissertation is focused on extending the information content for second harmonic generation (SHG) and two-photon excited fluorescence (TPEF) imaging. Despite the simplicity and symmetry selectivity of nonlinear optical processes, limited information on chemical composition can be recovered solely based on intensity measurements. To further explore the potential for second order nonlinear optical (NLO) measurements, additional dimensions were added to the NLO imaging platforms. By combining NLO microscopy with powder X-ray diffraction, a novel approach was established for accessing percent crystallinity in amorphous solid dispersions (ASDs) with a limit of detection in the ppm range. ASDs are …

Teacher Identity And The Role Of Relational Coaching, Melinda R. Ehmer

Open Access Dissertations

The purpose of this study was to identify specific strategies that principals use when coaching teachers who struggle to develop positive relationships with students. Using a qualitative case study design, six principals were identified through the use of a demographic survey. The principals were interviewed about their experiences. Each interview was recorded, transcribed, and coded for data analysis. The principals’ narratives, emerging themes and sub themes provide insight into their experiences with both relational and non-relational teachers. The emerging themes are: (a) relationship building for teachers and students; (b) coaching strategies; (c) roadblocks and deficiencies; and (d) identity and belief …

Quantum Correlations In Nanophotonics: From Long-Range Dipole-Dipole Interactions To Fundamental Efficiency Limits Of Coherent Energy Transfer, Cristian L. Cortes

Open Access Dissertations

Quantum properties like coherence and entanglement can lead to enhanced performance characteristics in a wide range of applications including quantum computation, quantum memory storage, optical sensing, and energy harvesting. Entanglement is very sensitive to static and dynamical disorder. Similarly, the generation of highly-entangled states requires strong coupling or strong driving fields. Satisfying all of these requirements is generally quite difficult. In the first part of this thesis, we present an approach to overcome these limitations through the use of exotic light-matter states in hyperbolic media which provide a new approach to control quantum correlations and interatomic interactions. We reveal a …

Influence Of Radical Proximity On The Charge Transport Of Nitroxide-Based Electronics, Martha E. Hay

Open Access Dissertations

As the societal dependence upon electronics continues to expand, consumer demand dictates the development of new materials to further augment both performance and user experience. Organic electronic materials enable unique features and applications due to the synthetic tunability of their optoelectronic properties, light weight, compatibility with flexible substrates, and biocompatibility. Radical polymers, macromolecules bearing pendant stable radical sites, have emerged as a new class of conducting polymers. These materials have demonstrated charge storage and transport capabilities in electrolyte-supported systems (e.g., secondary batteries) and have since been a source of inquiry for solid-state applications. Initial studies of their solid-state properties have …

The Design And Analysis Of Calcium-41 Clinical Trials To Study Treatments For Bone Loss, Courtney N. Henry

Open Access Dissertations

Calcium-41 (41Ca) is a biological tracer used to rapidly and sensitively monitor skeletal calcium metabolism. Measurements of the 41Ca:Ca ratio in urine quantify changes in net bone turnover (i.e. differences in bone formation and resorption). A biomedical application of 41Ca technology clinically assesses the efficacy of treatments for preventing bone loss, primarily targeting susceptible populations such as post-menopausal women.

This research initially describes a 41Ca simulation study to determine efficient 41Ca experimental designs that preserve the accuracy and reliability of estimation and the statistical power of our conventional design, whilst substantially lowering costs by reducing the number of samples and/or …

Model And Appearance Based Analysis Of Neuronal Morphology From Different Microscopy Imaging Modalities, Sarun Gulyanon

Open Access Dissertations

The neuronal morphology analysis is key for understanding how a brain works. This process requires the neuron imaging system with single-cell resolution; however, there is no feasible system for the human brain. Fortunately, the knowledge can be inferred from the model organism, Drosophila melanogaster, to the human system. This dissertation explores the morphology analysis of Drosophila larvae at single-cell resolution in static images and image sequences, as well as multiple microscopy imaging modalities. Our contributions are on both computational methods for morphology quantification and analysis of the influence of the anatomical aspect. We develop novel model-and-appearance-based methods for morphology quantification …

Investigating The Developmental Toxicity Of Legacy, Emergent, And Current Use Environmental Toxicants Using The Zebrafish Model System, Katharine Ann Marie Horzmann

Open Access Dissertations

Environmental toxicants are chemical or physical agents that enter the environment and can have adverse health effects on populations of humans. Chemical contamination of rivers, lakes, and ground water is a significant public health concern; 23% of private wells are contaminated with at least one significant environmental toxicant and chemical spill incidences can have severe consequences to human health and the environment. Even low doses of chemicals in the environment can have an effect on human health, and it is suggested by the Developmental Origins of Health and Disease (DOHaD) hypothesis that embryonic exposure to toxicants alters health status and …

System And Thermal Modeling Of Hydraulic Hybrids: Thermal Characteristics Analysis, Hyukjoon Kwon

Open Access Dissertations

Hybrid vehicles have become a popular alternative to conventional powertrain architectures by offering improved fuel efficiency along with various other environmental benefits. Among them, hydraulic hybrid vehicles (HHVs) have several benefits, which make it the superior technology for certain applications over other types of hybrid vehicles, such as lower component costs, more environmentally friendly construction materials, higher power densities, and more regenerative energy available from braking. There have been various studies on HHVs, such as energy management optimization, control strategies for various system configurations, the effect of system parameters on the hybrid system, and proposals for novel hybrid architectures. One …

The Impact Of Host Variables And Tumor Necrosis Factor On The Gut Microbiome In A Mouse Model Of Crohn's Disease, Ariangela J. Kozik

Open Access Dissertations

Crohn’s Disease (CD) and Ulcerative Colitis (UC) are chronic, inflammatory conditions of the digestive tract that are collectively known as Inflammatory Bowel Disease (IBD). Currently, IBD has no cure and the exact mechanisms of disease development and progression are unknown. The gut microbiome is the collection of microbes that reside in the digestive tracts of humans and animals, and it has been shown to be associated with a variety of diseases, including IBD. Mouse models of colitis are often used to investigate the role of the gut microbiome in IBD. In this work, I investigated the role of tumor necrosis …

Stereotype Threat, Perfectionism, And Women's Career Outcomes, Chaihua Lin

Open Access Dissertations

The underrepresentation of women in science, technology, engineering, and mathematics (STEM) calls for efforts to understand factors that contribute to women’s career development in STEM fields. Using social cognitive career theory (SCCT), this study examines how the interplay of individual and contextual factors (i.e., perfectionism and stereotype threat) contributes to the academic and career outcomes of women STEM students (i.e., self-efficacy, outcome expectation, interest, goals, and procrastination). Hypotheses regarding the relationships among these variables, as well as the moderating role of perfectionism on the mediated effect of stereotype threat on interest through self-efficacy were assessed. Data was collected from 323 …

Horses In Agriculture Online: Designing, Developing, And Assessing Situational Interest An Online Museum Exhibit Using The Systems Approach Model Of Instructional Design, Elisa Anne Lofgren

Open Access Dissertations

Research on motivations of learners has been done in traditional museum environments, but the research of online museum exhibits is in its infancy. While variables such as interactivity have been explored in traditional museum exhibits, little is still known about how these variables affect visitor experiences in online applications. It is important to know if the application of technology into these programs, such as online learning experiences and corresponding characteristics such as interactivity, free-choice use, and adaptive/adaptable e-learning effects the learner experience. This study follows a formal process of instructional design to develop an online educational resource to be used …

Global Analyses Of Protein Complex Localization, Oligomerization, Composition, And Dynamics Using Quantitative Mass Spectrometry, Zachary M. Mcbride

Open Access Dissertations

Proteins perform essential processes in plant cells such as photosynthesis, protein translation, maintenance of metabolic flux, and signal transduction. Many of these functions could never be achieved using individual proteins. Consequently, many proteins oligomerize to form complexes that act as tunable molecular machines that perform work and transmit information. Cells contain thousands of protein complexes, yet the composition of the vast majority remain unknown. Previous high throughput approaches to identify protein interactions have relied on binary interactions or tagging individual proteins for purification. A new set of label free correlation profiling methods were developed that extracted native protein from Arabidopsis …

Effects Of Anaerobic Digestion On Nutrient Conversion And Digestate Land Application On Nutrient Losses, Igor Moreira Lopes

Open Access Dissertations

The adoption of anaerobic digestion (AD) at agricultural systems as an alternative technology for waste management and renewable energy production has raised the concern regarding the value of AD digestate as fertilizer and the environmental impact of the digestate land-application. This Ph.D. research project aimed to gain new knowledge into the impact of AD on digestate characteristics in comparison with the digester feedstock, and the impact of digestate as fertilizer on water quality in comparison with inorganic fertilizer and raw manure. The project was divided into four different studies: a digestate characterization study and three digestate application studies. The digestate …

Effects Of Reduced Dietary Crude Protein On Gaseous Pollutant Emissions From A Swine Research Building, Shule Liu

Open Access Dissertations

Swine production is a primary source of protein and fat to human society, in the meanwhile, it continuously emits undesirable pollutant gases, including ammonia (NH3), hydrogen sulfide (H2S), carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O), imposing adverse impacts on animal and human health as well as on the environment. Previous studies proved that reducing excessive dietary N was effective in mitigating NH3 emissions from pig production, but the reduction in NH3 emissions during different swine physiological stages were not reported yet as only a few studies were based on continuous monitoring in the field. Moreover, the effects of …

Part I: Polyrotaxanes As Mri Contrast Agents And Npc Therapeutics. Part Ii: Development Of An Analytic-Directed Synthesis System, Bradley P. Loren

Open Access Dissertations

The work described in this dissertation is separated into two parts. Part I describes the development of cyclodextrin-based polyrotaxanes (PRs) as both MRI contrast agents and as potential therapeutics for Niemann-Pick Type C (NPC) disease. Polyrotaxanes are a class of supramolecular materials which are constructed through the non-covalent threading of macrocyclic molecules onto a polymer core that are retained by the covalent attachment of bulky molecules to the ends of the polymer as end-caps. This unique architecture provides a rigid and rod-like morphology that imparts attractive biological and mechanical properties compared to other nanomaterials used in biological applications. In our …

Yshb Is A Positive Regulator For Salmonella Intracellular Survival And Facilitates The Spatio-Temporal Regulation Of Bacterial Pathogenesis, Rajdeep Bomjan

Open Access Dissertations

Salmonella pathogenesis primarily involves invasion of host cells followed by modulation of the intracellular environment for survival and replication. While tremendous progress has been made toward understanding the pathogenesis, the picture is far from complete. In an effort to characterize the role of small RNAs (sRNAs) in Salmonella pathogenesis, we identified a previously undefined small protein YshB as a positive regulator for intracellular bacterial survival and virulence. Essentially, we were able to show YshB was important for survival within macrophages and contributed significantly in mouse virulence. Further, when induced within the bacteria, YshB would lower the invasion efficiency. Notably, yshB …

Batf Regulation Of Nfil3, Wnt10a, And Mir155hg During Lymphocyte Activation Critical For T Cell Differentiation And Antibody Class Switch Recombination, Rosemary E. Morman

Open Access Dissertations

B cell activating transcription factor (BATF), an immune specific AP-1 transcription factor, functions together with IRF4 and JUNB to regulate genes important for antibody class switch recombination (CSR) in B cells and for the functional differentiation of distinct CD4+T helper (Th) subsets, including Th2, Th9, Th17 and T follicular helper cells. At the time this work was initiated, the expression of BATF in T cells and B cells was known to be critical to the host response to antigen and for the production of class switched immunoglobulins, yet the precise details of how BATF functioned in those roles was unknown. …

Interplay Of Endogenous And Exogenous Biochemical Species On Neuropathic Pain After Spinal Cord Injury, Breanne Suzanne Muratori Butler

Open Access Dissertations

Neuropathic pain after spinal cord injury (SCI) presents a complex clinical challenge, affecting millions with no satisfactory treatment options currently available. Much of the recent research focuses on a wide variety of endogenous mechanisms that can contribute to pain, but have yet to produce positive results in clinical studies. This dissertation focuses on the role of a highly reactive and toxic aldehyde, acrolein, in initiating, instigating, and perpetuating neuropathic pain after spinal cord injury. Acrolein is shown to mimic damage caused by an injury, in the absence of mechanical trauma. Additionally, removing it using acrolein scavengers can mitigate neuropathic pain-like …

Plant Cell Wall Modification During Tomato Processing And Its Effects On The Physical And Rheological Properties Of End Products, Xing Fei

Open Access Dissertations

Understanding the relationship between structure and functional properties in plant-cell-wall-derived foods has become a growing interest to both academia and industry. Tomato is one of the most cultivated vegetable crops and mostly is consumed as processed products in the form of suspensions. Rheological properties of tomato product, a key functional attribute, depends on both the serum and particle phases of these products. Although recent studies have suggested that the particle phase is the dominant factor, the relationship between fundamental particle properties and the bulk rheology of the suspension is still unclear. This research systematically evaluated the contributions of soluble pectin …

Understanding Macroscale Patterns And Processes Of Invasion, Gabriela Nunez-Mir

Open Access Dissertations

The increasing rate of biological invasions and their impacts are one of the major threats in the Anthropocene. However, certain knowledge gaps remain in our understanding of patterns and processes of invasion, despite an extensive body of research dedicated to this phenomenon. Highly-debated topics in invasion ecology could benefit from a macrosystems perspective. Studies performed at the macroscale are able to capture the effect of global-level processes that drive invasions, detect patterns that transcend taxonomic and geographic boundaries, and minimize biases stemming from the specificity of studies performed at more localized scales. Here, I aim to provide novel insights into …

A Molecular Perspective For The Understanding Of Polymer‒Drug Interactions, Laura Isabel Mosquera Giraldo

Open Access Dissertations

Polymers are often used to stabilize amorphous drug formulations enabling the maintenance of high drug supersaturations. However, the molecular mechanism of stabilization is unclear, making the rational design of new polymers challenging. This research has focused on understanding the effectiveness of polymers to inhibit drug crystallization using experimental and computational modeling approaches. This thesis has six sections. The first section reviews the pharmaceutical significance of amorphous solid dispersions. The second section describes a study to evaluate the phase behavior of supersaturated drug solutions of telaprevir, a compound that undergoes glass-liquid phase separation when the amorphous solubility is exceeded. The third …

Enhancing Mirna Therapeutic Efficacy Through Combinatorial Targeting And Vehicle Free Delivery, Esteban A. Orellana

Open Access Dissertations

New alternative therapies to treat cancer have emerged such as the use of small molecules that target key oncogenic drivers. For instance, clinically relevant tumor suppressive microRNAs (miRNAs) that target key oncogenic drivers have been identified as potential therapeutics to treat cancer. MiRNAs are small non-coding RNAs that negatively regulate gene expression at the posttranscriptional level. It has been shown that aberrant miRNA expression, through misexpression of miRNA target genes, can have profound cellular effects leading to a variety of diseases, including cancer. While altered miRNA expression contributes to a cancerous state, restoration of miRNA expression has therapeutic benefits. For …

Nanoparticles With High Drug Loading And Circulation Stability For Systemic Delivery Of Anticancer Drugs, Joonyoung Park

Open Access Dissertations

Nanoparticles have been pursued as a promising strategy to improve the safety and therapeutic efficacy of systemic chemotherapy, but clinical translation of nanoparticle drug carriers has been slow. Several reasons account for the tedious progress. From the formulation perspective, drug loading efficiency and circulation stability remain to be improved: Low drug loading increases the amount of co-delivered carrier materials, imposing biological burdens to patients. Poor circulation stability compromises the pharmacokinetic benefits of nanoparticles. To develop nanoparticles with high drug loading efficiency and circulation stability, albumin-coated nanocrystal (“Abxtal”) formulation of hydrophobic anti-cancer drugs was developed. Abxtal consists of drug nanocrystals and …

Understanding The Molecular Mechanism Of Arsenic Tolerance And Accumulation In Pteris Vittata, Chao Cai

Open Access Dissertations

Arsenic is a toxic metalloid that is naturally occurring and widely distributed. The consumption of arsenic-contaminated food and water is threatening the health of millions of people in the world. The fern Pteris vittata is unusual in its ability to tolerate and hyperaccumulate exceptionally high concentrations of arsenic in its fronds. How P. vittata tolerates and accumulates arsenic is fundamentally different from that in angiosperms; however, the molecular mechanism underlying this trait in P. vittata is not well-defined. Because the haploid phase of the fern (the gametophyte) is morphologically simple, easy to grow and also tolerates and hyperaccumulates arsenic, the …

Depth-Resolved Assessment Of Atherosclerosis By Intravascular Photoacoustic-Ultrasound Imaging, Ayeeshik Kole

Open Access Dissertations

Coronary heart disease is the leading cause of death in the United States and the incidence is projected to increase by 18% by 2030. Yet, there remains a pressing clinical need for tools to detect vulnerable atherosclerotic plaques that can rupture and lead to major adverse cardiac events. Plaques that are considered most vulnerable for rupture are thin-capped fibroatheromas, which are grossly defined by hallmarks of a thin fibrous cap, a large lipid-rich necrotic core, inflammatory infiltrate, and positive remodeling. These plaques are often structurally non-obstructive to moderately obstructive, thus asymptomatic and clinically unidentifiable with routine angiography and stress testing. …