Master of Science, The Ohio State University, 2005, Graduate School

Committee: Not Provided (Other) Subjects:

Doctor of Philosophy, The Ohio State University, 2022, Astronomy

Galaxy formation and evolution are driven by stars and star formation. Star formation is fundamental for shaping the universe as we see it today as part of the cosmic ecosystems encompassing galaxies, yet half of the physics that determines how much gas forms into stars – the stellar feedback (injection of energy and momentum to the surrounding material) half of the tug-of-war between gravity and stellar feedback – have only recently become a focus for observational astronomers. Theoretical explorations of stellar feedback have been extensive for the past four decades and our current understanding of star-forming galaxies comes primarily through extensive modeling and simulations with sub-grid physics prescriptions based on a handful of observations. In order to secure the basis for these sub-grid physics models and expand our understanding of star-formation and the effects of massive stars during all epochs of the universe, more observations of these processes are needed. Observations of star forming regions provide the foundation to anchor simulations and observations of analogues to high-redshift galaxies help determine the sources that reionized the universe and the role stars played in during the Epoch of Reionization. With multiwavelength observations of H ii regions in the Milky Way, I have probed the effects of stellar feedback in dynamics of H ii regions, providing the necessary basis for defining the sub-grid physics in simulations. With multiwavelength observations of nearby galaxies with properties similar to galaxies in the EoR (low mass: < 107 M⊙; low metallicity: < 0.15 Z⊙; and high star-formation rates: > 10−1.2 M⊙/yr), I have determined the properties of sources that produce the photoionization feedback we observe and which sources ionized the universe in the Reionization Era. With X-ray observations of a massive colliding wind binary I have explored the effects of stellar wind feedback on small spatial scales and found that wind prescriptions assum (open full item for complete abstract)

Committee: Laura Lopez (Advisor); Todd Thompson (Committee Member); Adam Leroy (Committee Member) Subjects: Astronomy; Astrophysics

Master of Science, The Ohio State University, 2020, Biomedical Engineering

The molecular mechanisms driving age-related changes in lens material properties remains unknown. In this study, Raman spectroscopy was used to characterize structural differences in lens proteins between the cortex and nucleus, as well as changes resulting from exposure to acute ultraviolet (UV) radiation, a potential driver of age-related changes. Porcine lenses were obtained from a local abattoir and then used as control and experimental samples, separately. Nuclear and cortical lens protein portions were compared. Results were visualized, and statistical tests were performed to identify trends in protein structure. Protein concentrations in control samples matched published trends, while UV radiation produced changes in some lenses along with a cataract-like development in a single lens. While UV radiation changed capsular opacity in most samples, it caused opacification of the lens in one sample that coincided with other protein changes known to coincide with aging and cataract formation. Future studies should increase sample size and explore the dose-dependent changes in UV radiation exposure with both time and power adjusted to create different physiological simulations.

Committee: Matthew Reilly PhD (Advisor); Heather Powell PhD (Committee Member); Mark Ruegsegger PhD (Committee Member) Subjects: Biomedical Engineering

Doctor of Philosophy, The Ohio State University, 1985, Graduate School

Committee: Not Provided (Other) Subjects: Chemistry

Master of Science, University of Akron, 2017, Physics

Fluorescence refers to the emission of light after absorbing short wavelength energy and ceases within 10−6 seconds upon termination of excitation. In this thesis, the effects of low temperature—i.e., liquid nitrogen with a temperature of 77 K—on the emission spectra of industrial grade polymers were studied and compared with their room temperature fluorescence spectra. Multiple excitation energies with wavelengths that range from 250 nm to 450 nm (the ultraviolet spectrum) were used to isolate the most intense emission wavelengths at room temperature (300 K), and then again at 77 K to compare the temperature dependence of fluorescence for select polymer samples against themselves. The intensity of the fluorescence peak increases for cryogenic temperature measurements for all samples, with an acrylic sample displaying the largest intensity difference between the two temperatures. In addition to fluorescence spectroscopy, an analysis to evaluate the amount of light energy absorbed and transmitted through the polymers was implemented using an ultraviolet-visible spectrophotometer; demonstrating the samples absorb ultraviolet energy while permitting visible light to pass through most of them, resulting in the absorbed energy being released through photoluminescence.

Committee: Sasa Dordevic Dr. (Advisor); Robert Mallik Dr. (Committee Chair); Alper Buldum Dr. (Committee Member) Subjects: Condensed Matter Physics; Energy; Experiments; Low Temperature Physics; Materials Science; Physical Chemistry; Physics; Plastics; Polymer Chemistry; Polymers; Scientific Imaging; Solid State Physics

Master of Science in Chemistry, Cleveland State University, 2010, College of Sciences and Health Professions

This Master of Science thesis encompasses two projects in chemical pharmaceuticals. The first is a study of excipients and the added new information collected beyond Thermal Gravimetric Analysis and Differential Scanning Calorimetry from Dielectric Analysis. These new properties enhance our global knowledge of excipients by thermal analytical methods. Excipients, the inactive ingredients in formulated drugs, aid different functions of the active pharmacy ingredient, the drugs. Low temperature transitions, by DEA including melting of frozen solvents, e.g. water, are more definitive than observed by low temperature DSC. Millions of dollars are expended annually on pharmaceutical testing to qualify excipients for fully formulated drugs, medicines and active ingredients. To understand the action of the excipients in the human body at body temperature of 37°C, the study of their individual and interactive properties are desirable. DEA DSC and Thermal Gravimetric analysis (TGA) methods are employed to screen the most widely used drug excipients. In this study the following excipients were examined by DEA: cotton seed oil, mannitol, peanut oil, polyethylene glycol, sugar, sodium lauryl sulfate, sodium starch glycolate, sodium stearate, canola oil, and anhydrous lactose, benzoic acid and vanillin. The comparison of DSC and DEA thermal curves for each excipient indicates that major endothermic events have occurred e.g., volatilization or melting of the excipient are viewed as fundamental DEA properties. These properties are the rise in permittivity and dielectric loss factor. The focus of this project was to learn to prepare, examine and interpret the resulting variations. The electrical conductivity (e” * frequency* constant), permittivity (e') and tan delta value (e”/e') are used to enhance the characterization of the excipient. The second, and major project for this thesis, is to evaluate bipolar disorder drug transport with and without an applied electric field of (open full item for complete abstract)

Committee: Bin Su PhD (Committee Chair); Alan Riga PhD (Committee Co-Chair); Stan Duraj PhD (Committee Member); Tobili Sam-Yellowe PhD (Committee Member) Subjects: Analytical Chemistry; Chemistry