Physical Sciences and Mathematics Commons^™

Electron Paramagnetic Resonance Imaging And Probes, Hanan B. Elajaili

Electronic Theses and Dissertations

EPR imaging at low frequency is an important method to measure in vivo physiology. Because native paramagnetic species exist at low concentrations in living systems, exogenous paramagnetic species are needed for in vivo EPR. Selection of the appropriate EPR probe allows the experimenter to obtain information about the environment of the imaged probe and its spatial distribution. Relaxation times for several nitroxide radicals were studied with the aim of understanding the relaxation mechanisms, which provides criteria for design of suitable in vivo imaging probes.

Amino-substituted trityl radicals have the potential to monitor pH in vivo, and the suitability for this …

Molecular Encapsulation In Kinetically Trapped, Hydrogen-Bonded Pyrogallolarene Hexamers, Jennifer Christine Chapin Lake

Electronic Theses and Dissertations

Pyrogallolarene and resorcinarene hexamers are hydrogen-bonded capsules that self-assemble in the solid state and can be studied in gaseous and solution phases. Guest loading within pyrogallolarene hexamers in solution has primarily been comprised of solvent molecules with some tertiary amines. A novel solvent-free method for loading guests into the interior of the hexamer has been shown to be effective for encapsulation of a variety of molecules. Aromatic and aliphatic compounds have particularly high guest loading within the hexamers and often result in kinetically stable guest-filled capsules in solution.

Kinetic studies of the encapsulation complexes of anthracene, biphenyl, fluoranthene, fluorene, naphthalene, …

Dust And Pleistocene Ice Ages: Eolian Sediments And Climate Change At Ziegler Reservoir, Snowmass Village, Colorado, Jeffrey S. Honke

Electronic Theses and Dissertations

The discovery of the Ziegler Reservoir fossil site near Snowmass Village, Colorado presents an opportunity to examine subalpine ecosystem response, during a relatively unknown period, in which climate conditions were similar to present. Finegrained sediments at Ziegler Reservoir represent continuous deposition between ~140–55 ka (thousand years before present), spanning the close of the Bull Lake glacial period [marine isotope stage (MIS) 6], the Sangamon interglacial (MIS 5) and the early stages of the Pinedale (early Wisconsin) glacial period (MIS 4). Ziegler Reservoir is positioned on top of a ridge, at an elevation of 2705 m, and has a small watershed …

The Impact Of Internet Gis On Access To Water Quality Information, Joseph H. Hoover

Electronic Theses and Dissertations

Empowering citizens to comprehend complex environmental issues affecting their daily lives is essential to sustaining a healthy and informed public. The work of many environmental nongovernmental organizations (ENGOs) and institutions of higher education (IHEs) center around helping their stakeholders become informed of, and in turn, better understand complex environmental problems. However, providing individual stakeholders with knowledge about environmental issues that is easily accessible and understandable represents a recurring challenge in today's society. As a result, a gap continues to exist between that which is known about environmental problems and the public's awareness and understanding of those issues. Arsenic contamination of …

Nitroxide Radicals For Low Frequency Electron Paramagnetic Resonance Imaging (Epri), Joshua R. Biller

Electronic Theses and Dissertations

Optimization of nitroxides as probes for EPR imaging requires detailed understanding of spectral properties such as spin lattice relaxation times, spin packet linewidths, and nuclear hyperfine splitting. Initial measurements of relaxation times for six low molecular weight nitroxides at X-band stimulated further measurement at frequencies between 250 MHz and 34 GHz. The impact of tumbling was studied with perdeuterated 2,2,6,6-tetramethyl-4-piperidinyl-1-oxyl (PDT) in five solvents with viscosities resulting in tumbling correlation times, τ_R, between 4 and 50 ps. A set of three ¹⁴N/¹⁵N pairs of nitroxides in water was selected such that τ_R varied between …

Photoassisted Access To New Polyheterocycles, Teresa M. Cowger

Electronic Theses and Dissertations

Photoassisted diversity-oriented synthesis holds great promise in its ability to provide rapid access to complex and diverse molecular scaffolds. As it stands, while photochemical techniques have this potential, their implementation in the field of synthetic organic chemistry is very limited. The main goal of this project was to utilize photochemically assisted techniques in the synthesis of a variety of novel polyheterocycles.

Initially, we explored the how the strain installed in these polycycles could be harnessed to trigger cationic rearrangements in the framework of the system. This was achieved via the high yield and rapid assembly of a highly strained system …

Measurement Of Low Temperature Thermal Properties Of Microcalorimeters Using Johnson Noise Thermometry, Dain Bassett

Electronic Theses and Dissertations

Calorimetric measurments and thermal transport measurments through a-Si_xN_y suspended membranes have been performed to further the understanding of low temperature thin film thermal transport, and understand the interesting physics present within an amorphous dielectric material. The thermal properties of several calorimeters have been measured to understand the geometric dependence on transport phenomenon. We analyze and compare our results with observations of previous measurements, and with those indicating quantum limited thermal transport. We see strong indications of changes to the physical mechanism transporting heat through these materials as temperature changes from 50 mK to 2 K. We have …

Probing Structure For Photophysical Properties Through Synthesis Of Novel Nucleosides, Brittney Jean Rodgers

Electronic Theses and Dissertations

A brief history of nucleosides and their photophysics provides the background information for the discussion of synthesis, photophysics and incorporation of fluorescent nucleotide analogs during enzymatic DNA synthesis. Through the use of nucleoside starting material, it is possible to synthesize a number of modified nucleotides for use as fluorescent probes in biochemical research. Synthetic endeavors into the synthesis of these and related molecules from nucleobase starting materials are also presented. The synthesis of these molecules involved re-development of the synthetic routes to broaden substrate scope by overcoming the changed reactivity resulting from the presence of additional functionality.

While many highly …

Topological Ramsey Spaces, Associated Ultrafilters, And Their Applications To The Tukey Theory Of Ultrafilters And Dedekind Cuts Of Nonstandard Arithmetic, Timothy Onofre Trujillo

Electronic Theses and Dissertations

This dissertation makes contributions to the areas of combinatorial set theory, the model theory of arithmetic, and the Tukey theory of ultrafilters. The main results are broken into three parts.

In the first part, we identify some new partition relations among finite trees and use them to answer an open question of Dobrinen; namely, "for n < omega, are the notions of Ramsey for Rn and selective for Rn equivalent?" We show that for each n < omega, it is consistent with ZFC that there exists a selective for Rn ultrafilter which is not Ramsey for Rn.

In the second part, we extend results of Blass concerning Dedekind cuts associated to ultrafilter mappings from p-point and weakly-Ramsey ultrafilters to ultrafilter mappings from Ramsey for R1 ultrafilters. Blass associates to each ultrafilter U on a countable set X and each function g …

Nanoscale Thermoelectrics: A Study Of The Absolute Seebeck Coefficient Of Thin Films, Sarah J. Mason

Electronic Theses and Dissertations

The worlds demand for energy is ever increasing. Likewise, the environmental impact of climate change due generating that energy through combustion of fossil fuels is increasingly alarming. Due to these factors new sources of renewable energies are constantly being sought out. Thermoelectric devices have the ability to generate clean, renewable, energy out of waste heat. However promising that is, their inefficiency severely inhibits applicability and practical use. The usefulness of a thermoelectric material increases with the dimensionless quantity, ZT, where, Z = S²σ/κ, and S, σ, and κ are the Seebeck coefficient and electrical and thermal …