Thesis (Ph.D.)--University of Adelaide, Dept. of Physical and Inorganic Chemistry, 1966. / Typescript.

Thesis (M.S.)--University of Wisconsin--Madison, 1969. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (M. Eng.)--Carleton University, 2001. / Includes bibliographical references. Also available in electronic format on the Internet.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1981. / Typescript. Vita.

The short-term interaction between nitrate and ammonium uptake was examined for a marine diatom, Thalassiosira pseudonana, grown in the continuous turbidostat cultures under different degrees of light limitation. Nitrate uptake in the absence and in the presence of ammonium and ammonium uptake in the absence and in the presence of nitrate were measured during a 6 min time course after a solution of both nitrate and ammonium was passed across the cells trapped on the filter. It was found that the interaction between nitrate and ammonium uptake occurred immediately and continued for the remainder of the time course. The effect of light on the interaction was apparent. In the less light-limited cultures, nitrate uptake was depressed by ammonium. In contrast, in the most light-limited culture, the depression of nitrate uptake by ammonium disappeared. Ammonium uptake was dependent on the degree of light limitation of the cultures. For all the cultures, ammonium uptake was initially enhanced and then declined with time. However, only the initial (1 min) enhanced uptake of ammonium was suppressed by the presence of nitrate, and the subsequent ammonium uptake rate was unaffected. Possible explanations and the ecological significance of the interaction are discussed. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

A number of methods are currently in use for attenuating nitrates from wastewater with varying degrees of efficiency. Bioremediation using bacteria may be an efficient and cost effective method. In an anaerobic bioremediation system, nitrate can replace carbon dioxide as an electron acceptor and aids in nitrate attenuation by assimilatory reduction. The purpose of this study was to investigate nitrate attenuation in a hyperfiltration system using a pure culture of strictly anaerobic, facultative Methanobrevibacter ruminantium bacteria. Filtration experiments were conducted using amalgamated Na- montmorillonite clay-glass beads compacted at 500 psi differential hydraulic pressure with or without a biofilm. A simulated agricultural wastewater of 3.105?10-4 moles/L of NO3- was bioremediated. The use of bacteria in attenuating nitrates offers promising results on a bench-scale.

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Thèse (M.Sc.) -- Université Laval, 1997. / Bibliogr.: f. 61-66. Publ. aussi en version électronique.

Nitrate is a progenitor of nitric oxide found in high concentrations in diets rich in fruits and vegetables, such as the Mediterranean. Following enterosalivary circulation, nitrate is converted by salivary bacteria to nitrite and then nitric oxide. Nitrite is a bioactive metabolite of nitric oxide hypothesised to play a role in several metabolic pathways. We explored the effect of nitrate and nitrite in skeletal muscle metabolism and mitochondrial function in mice and humans. Our aims were to assess whether the mouse model is appropriate for use to ascertain the effects of nitrate supplementation, to determine whether these effects are nitrate or nitrite dependent and to investigate whether 7 days nitrate supplementation with nitrate in humans affects metabolism and mitochondrial function. Nitrate supplementation in the mouse, increased plasma nitrate concentration but did not elicit any changes in skeletal muscle metabolism or mitochondrial function at rest. Nitrite supplementation increased plasma nitrate and nitrite concentrations and achieved an increase in metabolic efficiency manifested as a reduction in complex I-linked leak respiration at rest. Nitrate supplementation in humans for 7 days increased plasma nitrate but not nitrite concentration. Skeletal muscle metabolism and mitochondrial function after nitrate did not differ from the placebo. However, blood perfusion of muscles consisting predominantly of type I fibres was increased. Our work suggested that nitrate metabolism is similar between mice and humans and the mouse could be a good model to investigate the effects of nitrate supplementation on skeletal muscle metabolism. This work also suggests that increases in plasma nitrite concentration may be responsible for the changes observed in mitochondrial efficiency. Finally, nitrate supplementation in humans did not elicit any metabolic changes. Deliberate nitrate supplementation in order to increase performance requires further research and any recommendations on increased consumption of nitrates for this purpose may not be accurate.