Physical Sciences and Mathematics Commons^™

Experimental And Statistical Techniques To Probe Extraordinary Electronic Properties Of Molecules, Byron Hager Smith

Doctoral Dissertations

The existence of an additional electron or hole in the presence of an electric monopole is a well understood physical system, but this ideality is far from the true physical properties of many molecules. Examples of such irregular electronic states include the attachment of an excess charge to a molecule's dipole moment, electronic correlation spanning a molecule, or attachment of multiple excess charges. Current theoretical and experimental interpretations widely vary for these states and further elucidation of the nature of irregular electronic structure may provide solutions to unexplained observations and the impetus for industrial application. For example, in the case …

Radiogenic Second Cancer Risk Differences In Female Hodgkin Lymphoma Patients Treated With Proton Versus Photon Radiotherapies, Kenneth L. Homann

Dissertations & Theses (Open Access)

Hodgkin Lymphoma (HL) is the most common cancer diagnosis of young adults in the United States. Advances in curative treatments for HL, including the use of photon radiation therapy (RT) techniques, have increased 10 year survival rates to approximately 90% among young patients. These RT treatments, however, contribute to an increased incidence of radiogenic second cancer (RSC) formation to the healthy tissue surrounding the tumor volume relative to the general population. These RSCs are the leading cause of death among long-term HL survivors. Proton therapy has been shown to reduce the therapeutic dose, and therefore, the risk of developing a …

Fabricating Cost-Effective Nanostructures For Biomedical Applications, Erden Ertorer

Electronic Thesis and Dissertation Repository

In this thesis we described inexpensive alternatives to fabricate nanostructures on planar substrates and provided example applications to discuss the efficiency of fabricated nanostructures.

The first method we described is forming large area systematically changing multi-shape nanoscale structures on a chip by laser interference lithography. We analyzed the fabricated structures at different substrate positions with respect to exposure time, exposure angle and associated light intensity profile. We presented experimental details related to the fabrication of symmetric and biaxial periodic nanostructures on photoresist, silicon surfaces, and ion-milled glass substrates. Behavior of osteoblasts and osteoclasts on the nanostructures was investigated. These results …

Three-Dimensional Electrokinetic Trapping Of A Single Fluorescent Nanoparticle In Solution, Jason Keith King

Doctoral Dissertations

This dissertation presents the development of an instrument for effectively trapping a single fluorescent nanoparticle that is freely diffusing in solution in all three dimensions. The instrument is expected to have applications for studies of single nanoparticles or molecules for which prolonged observations are required, but without immobilization or proximity to a surface, which may alter behavior. The trapping technique depends on rapid three-dimensional position measurements of the nanoparticle with sub-micron precision, which are used for real-time control of induced electrokinetic motion, so as to counteract Brownian motion. While anti-Brownian electrokinetic trapping experiments in one and two dimensions have previously …

Organic Polymer Solar Cells: The Effects Of Device Packaging On Cell Lifetime, Spencer Herrick

Physics

As the earth runs out of nonrenewable energy sources and climate change starts to have drastic effects on the environment, the world is becoming increasingly desperate for cost efficient, renewable energy sources. Organic polymer based solar technology is a cutting edge approach to meeting the world’s energy demands. We fabricate single-layer, organic photovoltaics devices that utilize the electrical characteristics of semi-conductive polymers. These solution processable materials are beneficial due to their low material cost, lightweight, and simple fabrication requirements. Our devices utilize multiple photoactive polymers, P3HT and PCPDTBT, to absorb photons over a wide spectral range. We optimized various device …

Simulation Of Electronic Processes Of Nanoenergetic Gas Generator Using Cabrera Mott Oxidation Model, Zamart Ramazanova

Theses and Dissertations - UTB/UTPA

This research study is a theoretical framework for understanding rapid thermal processes which occur during the performance of new Nanoenergetic Gas-Generators (NGG) systems that rapidly release a large amount of gaseous products and generate a fast-moving thermal wave during the explosion. The kinetics of rapid oxidation of metal nanoparticles acquires practical importance with the quickly developing nanoenergetic systems. The thin film oxidation theory of Cabrera-Mott model was examined for a spherically symmetric case and used to analyze the physical importance of the exothermic processes for prediction of the reaction time and front velocity. A rapid kinetic of oxide growth on …

Dynamics Of The Fitzhugh-Nagumo Neuron Model, Zechariah Thurman

Physics

In this paper, the dynamical behavior of the Fitzhugh-Nagumo model is examined. The relationship between neuron input current and the firing frequency of the neuron is characterized. Various coupling schemes are also examined, and their effects on the dynamics of the system is discussed. The phenomenon of stochastic resonance is studied for a single uncoupled Fitzhugh-Nagumo neuron.

Application Of Computational Molecular Biophysics To Problems In Bacterial Chemotaxis, Davi Ortega

Doctoral Dissertations

The combination of physics, biology, chemistry, and computer science constitutes the promising field of computational molecular biophysics. This field studies the molecular properties of DNA, protein lipids and biomolecules using computational methods. For this dissertation, I approached four problems involving the chemotaxis pathway, the set of proteins that function as the navigation system of bacteria and lower eukaryotes.

In the first chapter, I used a special-purpose machine for molecular dynamics simulations, Anton, to simulate the signaling domain of the chemoreceptor in different signaling states for a total of 6 microseconds. Among other findings, this study provides enough evidence to propose …

In Silico Modeling The Effect Of Single Point Mutations And Rescuing The Effect By Small Molecules Binding, Zhe Zhang

All Dissertations

Single-point mutation in genome, for example, single-nucleotide polymorphism (SNP) or rare genetic mutation, is the change of a single nucleotide for another in the genome sequence. Some of them will result in an amino acid substitution in the corresponding protein sequence (missense mutations); others will not. This investigation focuses on genetic mutations resulting in a change in the amino acid sequence of the corresponding protein. This choice is motivated by the fact that missense mutations are frequently found to affect the native function of proteins by altering their structure, interaction and other properties and cause diseases. A particular disease is …