Thesis (Ph. D.)--University of Wisconsin--Madison, 1910. / Cover title. Reprinted from Journal of physical chemistry, vol. 15, no. 1 (Jan. 1911), p. 1-19. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (Ph. D.)--Cornell University, 1912. / Description based on print version record. Includes bibliographical references (p. [107]-110).

Thesis (Ph. D.)--University of Washington, 1923. / Reprinted from the Journal of the American Chemical Society, v. 46, no. 6, June, 1924.

Thesis (M.S.)--University of Missouri-Columbia, 2004. / Typescript. Includes bibliographical references (leaves 54-58). Also available on the Internet.

In order to elucidate the mechanism of hydrogen sulphide oxidation, the photo-oxidation and thermal oxidation of hydrogen sulphide were studied, using gas chromatography for the analysis of final products. Photo-oxidation was studied at 130° and 150°C. Products found were sulphur dioxide, hydrogen, water and sulphur. Production of sulphur dioxide was found to be inhibited by an increase in surface area. Whether in photo- or thermal oxidation, the yield of sulphur dioxide increased drastically with slight increases in (O₂)/H₂S) ratio. This was also observed in the yield of hydrogen in photo-oxidation. Thermal oxidation was studied at 160°, 170°, 190°, 210°, 225°, 240°, and 260°C. Products were sulphur dioxide, water, and sulphur. No hydrogen was found. An expression for the production of sulphur dioxide was obtained: [formula omitted] = k (H₂S)⁻¹→⁺¹ (O₂)³ The overall activation energy was found to be 21.2±2k.cal./mole. Comparison with previously reported works was made and a mechanism proposed. / Science, Faculty of / Chemistry, Department of / Graduate

Hydrogen sulfide (H2S) is a novel neurotransmitter that has been shown to influence cardiovascular function as well as other autonomic and endocrine functions by targeting a wide range of ion channels. Using whole-cell electrophysiology, I have investigated the potential role of H2S in the regulation of neuronal excitability in the paraventricular nucleus of the hypothalamus (PVN), which is a central relay centre for autonomic and endocrine function. In current-clamp recordings, sodium hydrosulfide hydrate (NaHS), when perfused onto PVN slices at various concentrations (0.1, 1, 10, and 50 mM), elicited a concentration-dependent response relationship from the majority of recorded neurons, with almost exclusively depolarizing effects. Input resistance differences from baseline, and during the NaHS-induced depolarization, uncovered a biphasic response, implicating both a potassium (K+) and non-selective cation conductance. In order to further investigate H2Ss effects on K+ conductances, we used both voltage- and current-clamp techniques to examine the effects of NaHS at either 1 or 10 mM on both the transient and sustained voltage-activated K+ currents in these neurons. We applied TEA+ (10 mM) to isolate the transient/rapidly inactivating current (IA) and 4-AP (5 mM) to isolate the sustained/delayed rectifier current (IK), and were able to show that both of these conductances were significantly reduced by H2S. Finally, we were able to demonstrate, using current-clamp, that when 4-AP and TEA+ were applied together with NaHS, they were able to completely eliminate the previously observed NaHS-induced depolarization, and the effects on membrane potential reversed to show a small hyperpolarization. These data highlight the potential role of H2S as a critical modulator of the voltage-gated repolarizing conductances, IA and IK, which in turn regulate neuronal excitability within the PVN. This can have a large impact on the way neurotransmitters and hormones such as vasopressin, oxytocin, corticotrophin-releasing hormone, and thyrotrophin-releasing hormone are released from the PVN, which influence a wide range of neuroendocrine and autonomic functions such as cardiovascular function, fluid balance, and food intake. / Thesis (Master, Neuroscience Studies) -- Queen's University, 2013-09-13 10:51:34.585

In recent years, hydrogen sulfide (H2S) has garnered interest as the third addition to the gasotransmitter family. Essential to human physiology, H2S has roles in the cardiovascular, nervous, and respiratory systems and perturbations in physiological H2S levels have been correlated to a variety of diseases. As a result, there has been significant interest in the development of H2S-releasing compounds (H2S donors) that can mimic slow, enzymatic production for research and therapeutic applications. While a large library of H2S donors exists, several common drawbacks persist, such as: lack of spatial and temporal control, poorly understood mechanisms of release, uncontrolled kinetics, and low efficiency. These issues significantly limit the biological applications of many H2S donors. This dissertation describes recent work to provide biocompatible H2S donors with controllable release kinetics using a robust, novel strategy for H2S delivery that relies on rapid enzymatic hydrolysis of carbonyl sulfide (COS) to H2S by the ubiquitous mammalian enzyme carbonic anhydrase (CA). Self-immolative thiocarbamates can be designed to release COS by a variety of stimuli, and in biological milieu this COS is rapidly converted to H2S by CA. This strategy has enabled the development of the first analyte-replacement fluorescent probe for H2S and has become a popular strategy for H2S delivery in a variety of applications. Additionally, the unexpected cytotoxicity profile of enzyme-activated COS/H2S donors has piqued interest in COS chemical biology, and these donors are being used as tools for studying COS itself. This dissertation includes previously published and unpublished coauthored work. / 2021-04-30

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Thesis (Ph.D.)--University of Tulsa, 1989. / Bibliography: leaves 124-130.