Thesis (Ph. D.)--University of Washington, 2006. / Vita. Includes bibliographical references (leaves 75-91).

The binding energies and momentum profiles for each of the valence orbitals of CO and H₂S have been measured by high momentum resolution electron momentum spectroscopy. The experimental momentum profiles are compared on a quantitative basis within the Target Hartree-Fock Approximation to theoretical calculations using SCF wavefunctions ranging in quality from minimal basis to Hartree-Fock limit. Calculated momentum distributions for the 5σ orbital of CO are shown to be very basis set dependant while calculated momentum distributions of the CO 3σ, 4σ and 1π orbitals change very little with improvements in the wavefunction beyond the double-zeta level. The CO 1π orbital is not very well described in the low momentum region even at the Hartree-Fock limit with basis set saturation including diffuse functions. While the 4a₁, and 2b₂ momentum profiles of H₂S are well described using even minimal basis calculations, diffuse functions must be included in the basis set to describe the 2b₁, and 5a₁, momentum profiles. The experimental momentum profiles of H₂S are also compared with full ion-neutral overlap calculations incorporating correlation in the ground state and correlation and relaxation in the final ion state. These calculations are very similar to the Hartree-Fock level momentum distributions, indicating that correlation is not very important in describing the momentum profiles of H₂S. The binding energy spectra and momentum profiles of the inner valence region of both CO and H₂S are studied in detail. Peaks in the CO binding energy spectrum at 24.1 and 28.3 eV are assigned as satellites 4σ and 1π main lines respectively while the structure above 30 eV is shown to be predominantly due to satellites of the 3σ orbital. The intense structure in the inner valence region of H₂S is found to arise predominantly from the 4a₁, orbital. The assignments of the inner valence spectra of both molecules is confirmed within experimental uncertainties by the spectroscopic sum rule. / Science, Faculty of / Chemistry, Department of / Graduate

No description available.

Hydrogen sulfide (H2S) has emerged as an important mediator of host function. In the gastrointestinal tract H2S is enzymatically produced and plays a vital role in cytoprotection, inflammation, and tissue repair. During a bout of colitis, the ability of the colon to produce H2S is markedly increased and drives the resolution of colitis. However, little is known about how the production of H2S is regulated in the colon and how dysregulated production can affect the course of colitis in vivo. Additionally, the mechanisms through which H2S can promote the resolution of colitis remain to be fully investigated. In Chapter 3 of this dissertation, the regulation of H2S production in the colon was explored by examining the contributions of three enzymatic pathways to colonic H2S synthesis. The largest source of the H2S synthesis was from a pathway previously unrecognized in the GI tract involving the enzyme 3-mercaptopyruvate sulfurtransferase (3MST). Additionally we found that the upregulation of H2S production during colitis occurred specifically at sites of mucosal ulceration. At the same time H2S inactivation via the enzyme sulfide quinone reductase (SQR) was significantly reduced at these sites. We propose that the site-specific alterations in H2S production and inactivation during colitis promote the resolution of inflammation and injury. Chapter 4 examined whether the ability of hyperhomocysteinemia (Hhcy) to exacerbate colonic inflammation occurred through impaired H2S synthesis. Hyperhomocysteinemia is often reported in patients with inflammatory bowel disease and is a consequence of decreased vitamin B intake. In all three models tested, diet-induced Hhcy significantly exacerbated colitis. Being dependent on vitamin B6 as a co-factor, the increased H2S production normally observed during colitis was abolished during Hhcy. Administration of an H2S donor to Hhcy rats significantly decreased the severity of colitis. These results also uncovered a novel role for IL-10 in promoting H2S production and homocysteine metabolism, which may have therapeutic value in conditions characterized by Hhcy. Finally, in Chapter 5 we looked for a mechanism through which H2S can promote resolution of colitis. Using CSE-deficient mice we found that H2S production was required to maintain HIF-1α signaling in the colon. Additionally, proper HIF-1α signaling was required for H2S-donating molecules to promote the resolution of colitis. These results suggest that HIF-1α signaling is a critical event through which H2S promotes resolution of colitis. Collectively, these chapters further highlight the importance of H2S production in colon during inflammation and injury and offer insight into new therapeutic targets mediated through H2S. / Dissertation / Doctor of Philosophy (PhD)

Confined animal feeding operations (CAFOs) relating to swine and their resulting odors continues to be an issue of concern. The primary sources of odors from a CAFO include general ventilation of the confinement house, the anaerobic lagoon, and the land application of lagoon sludge. This paper focuses on lagoon wastewaters, but the results therein could have influence on the other two aforementioned areas. An advanced upflow anaerobic/aerobic reactor system was developed to determine its impact on microbial activities that ultimately result in offensive odors. The microbial activity of SRB (sulfate-reducing bacteria) and hydrogen-sulfide production was monitored closely in each ?zone?, as well as other parameters such as dissolved oxygen and BOD. The results indicated a microbial physiology conducive to offensive odor production in the anaerobic zone of the pilot reactor and an aerobic microbial population in the upper zone of the pilot reactor. This aerobic zone was found to be effective in oxidizing the odorous gases created in the anaerobic zone. The overall microflora was consistent with an average magnitude of 108 CFU/mL. From the analysis performed, it was concluded that the microbiotic flora development and related substrate decomposition was the result of different metabolic pathways employed by the microflora rather than changes in the microbial population. In addition, the rise in pH throughout the experiment indicated the impact of the protein metabolic pathways (ammonification) over the carbohydrate metabolic pathways. Overall, the upflow anaerobic/aerobic pilot reactor proved to be an effective method for ?zoning? of the microbiotic flora, and a positive impact on the modifying the compounds related to offensive odor production.

No description available.

Peptide amphiphiles (PAs), peptides that self-assemble into hydrogels with a nanofibrous network, are interesting biomaterials due to their biocompatibility and biodegradability. Self-assembling peptide-based materials include a wide range of peptide motifs that form one-dimensional nanostructures in aqueous solution. Two different PAs are considered in this M.S. thesis work: lipidated peptides, and gas-releasing peptides (GRPs). These biomaterials have been developed to function as potential therapeutics that promote the growth of new blood vessels. The analyses conducted on the lipidated peptides, which were designed to include a peptide sequence that promotes angiogenesis, include cytotoxicity, viability, and tube formation assays. The GRPs were designed to release H2S, which is also capable of promoting angiogenesis. Several characteristic properties of the GRPs were analyzed, including morphology, mechanics, self-assembly, and gas release rates. Furthermore, cytotoxicity assays were conducted followed by the demonstration of gas uptake in endothelial cells. / Master of Science

Thesis (Ph. D.)--Ohio State University, 2007. / Title from first page of PDF file. Includes bibliographical references (p. 185-195).

No description available.

Air pollution has adverse effects on human health. The respiratory system is the most exposed and short-term changes in air pollution levels have been associated with worsening of asthma symptoms and increased rates of heart attacks and stroke. Air pollution in cities due to traffic is the major concern, as many people are exposed. However, natural sources of air pollution such as natural dust storms and ash from volcanic eruptions can also compromise human health. Exposure to volcanic eruptions and other natural hazards can also threaten mental health. Air pollution has not been extensively studied in Iceland, in spite of the presence of several natural pollution sources and a sizeable car fleet in the capital area. The aim of this thesis was to determine if there was a measurable effect on health which could be attributed to air pollution in Iceland. This aim was pursued along two paths; time series studies using register data aimed to determine the short-term association between daily variation in air pollution and on one hand daily dispensing of anti-asthma medication or the daily number of emergency room visits and emergency admissions for cardiopulmonary causes and stroke. The other method was to investigate if exposure to the Eyjafjallajökull volcanic eruption was associated with adverse health outcomes, either at the end of the eruption, or 6 months later. In paper I time series regression was used to investigate the association between the daily number of individuals who were dispensed anti-asthma medication and levels of the air pollutants particle matter with an aerodynamic diameter less than 10 μm (PM10), nitrogen dioxide (NO2), ozone (O3), and hydrogen sulfide (H2S) during the preceding days. For the study period 2006-9, there were significant associations between the daily mean of PM10 and H2S and the sales of anti-asthma medication 3 to 5 days later. Giving the exposure as the highest daily one-hour mean gave more significant results. Air pollution negatively affected the respiratory health of asthma medication users, prompting them to refill their prescriptions before they had originally intended to. In paper II the main outcome was the number of individuals seeking help at Landspitali University Hospital emergency room for cardiopulmonary disease or stroke. Time series regression was used to identify the lag that gave the best predictive power, and models were run for data for 2003-9 pollutants PM10, NO2, and O3. O3 was significantly associated with the number of emergency hospital visits the same day and two days later in all models, and both for men, women and the elderly. Only emergency hospital visits of the elderly were associated with NO2, and there were no associations with PM10. In paper III the aim was to investigate if the health effects of PM10 were affected by the addition of volcanic ash from the 2010 eruption of Eyjafjallajökull and 2011 eruption of Grímsvötn to PM10 in the capital area. Time series regression of emergency hospital visits and PM10 before and after the Eyjafjallajökull eruption showed that the effect tended to be higher after the eruption, but the results were not significant. Analysis with a binary indicator for high levels of PM10 from volcanic ash and other sources showed that volcanic ash was associated with increased emergency hospital visits. There were no associations with high levels of PM10 from other sources. In paper IV, the health of the population exposed to the ongoing eruption of Eyjafjallajökull in 2010 was investigated thoroughly. Lung function in adults was better than in a reference group from the capital area, though many reported sensory organ irritation symptoms and symptoms of stress and mental unhealth, especially those with underlying diseases. Paper V report the results from a questionnaire study which was carried out six months after the Eyjafjallajökull eruption. The study population comprised a cohort of south Icelanders exposed to the eruption to varying degrees and a reference group from north Iceland. Respiratory and eye symptoms were much more common in south Icelanders than in the reference group, after adjusting for demographic characteristics. Mental unhealth rates had declined considerably. In the studies, we found that urban air pollution and natural particles have short-term effects on anti-asthma medication dispensing and emergency room visits and hospital admissions. Exposure to natural particles in the form of volcanic dust was associated with increased respiratory symptoms in a very exposed population. There were indications that volcanic ash particles were associated with increased emergency hospital visits in the following days. / <p>Statement of collaboration</p><p>This thesis and the work in it have been produced in collaboration between University of Iceland and Umeå University. The thesis was issued and defended at both institutions. Responsible</p>