Thesis (PhD. (Paraclinical Studies))--University of Pretoria, 2004. / Includes bibliographical references.

Thesis (M.S.)--Oregon State University, 2005. / Printout. Includes bibliographical references (leaves 53-56). Also available on the World Wide Web.

Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1993. / Vita. Abstract. Includes bibliographical references (leaves 125-126). Also available via the Internet.

A dissertation submitted to the Faculty of Science, in partial fulfilment of the requirements for the award of Master of Science degree, University of the Witwatersrand, Johannesburg, 2018 / Three mixed-ligand metal-metal bonded complexes containing one unsymmetrical anionic bridging ligand were successfully synthesized and characterized as to their electrochemical and spectroscopic properties. The investigated mono-substituted diruthenium complexes have the general formula, Ru2(OAc)3(L)Cl, where OAc = acetate anion and L = anilinopyridinate bridging ligand (ap, 2-Meap, 2-Fap). UV/Visible spectroscopy studies reveal that the investigated diruthenium complexes exist in the forms Ru2(OAc)3(L)Cl and [Ru2(OAc)3(L)]+ in solution. The two forms are observed as a split band in the 500 – 700 nm visible region. A collapse of one band is seen upon reaction of the complexes with excess halide (Cl-, Br-) indicating an equilibrium shift towards the neutral species in solution, whereas a reaction with AgBF4 precipitates the chloride as the AgCl salt, leaving only the cationic species in solution. Electrochemical characterization of the mixed-ligand diruthenium complexes conclusively reveals a stable Ru25+ oxidation state in all three complexes. Upon an applied potential in a non-coordinating solvent, each complex undergoes a reversible one-electron oxidation and reduction process accessing the Ru26+, and Ru24+ oxidation states respectively. The treatment of human breast adenocarcinoma MCF-7 cells with these water-soluble complexes results in a less than 50 % cell survival. This demonstrates significance of solubility in the development of metallodrugs for cancer treatment. / XL2018

Some species of marine phytoplankton are believed to be more tolerant of high concentrations of trace metals than others, but no conclusive test of this hypothesis has been conducted. Eleven species of phytoplankton representing 5 classes were grown in Aquil medium containing Cd$ sp{2+}$ concentrations between 10$ sp{-9.85}$ and 10$ sp{-6.84}$ M. Growth rates and intracellular concentrations of Cd, C, N and S were measured. Cadmium quotas (mol Cd/litre-cell volume) were lower in members of Bacillariophyceae than in Chlorophyceae, Prymnesiophyceae, Dinophyceae and Cyanophyceae (ANOVA, p $<$ 0.001). Cellular C:S molar ratios decreased in phytoplankton grown at high (pCd 7.37-6.84) compared to low Cd (no added Cd), as S/litre-cell volume increased. Similar results were observed for C:N molar ratios. In two species that were examined, C:S ratios decreased as a linear function of increasing Cd concentration. Mean Cd$ sp{2+}$ concentration that reduced growth rate to 50% of maximum (pCd$ sp{50})$ was not significantly different among phytoplankton classes (ANOVA, p $<$ 0.05). When these experimental data were combined with pCd$ sp{50}$s calculated from published sources, Chlorophyceae were found to be the most resistant class (ANOVA, p $<$ 0.01). Cadmium and Cu resistance (pCd$ sp{50}$ and pCu$ sp{50})$ were correlated (r = 0.52, p $<$ 0.05), suggesting co-tolerance of phytoplankton to toxic levels of these metals. Chlorophyceae were most tolerant and Cyanophyceae the least tolerant of Cu (ANOVA, p $<$ 0.01). No significant differences were observed among Bacillariophyceae, Prymnesiophyceae, and Dinophyceae, which were of intermediate sensitivity to both metals. The results confirm the existence of a phylogenetic dependence of resistance to trace metal toxicity in phytoplankton.

Thesis (MSc (Paraclinical Sciences))--University of Pretoria, 2007. / Includes bibliographical references. Also available in print format.

No description available.

A large range of polymers are used in building and mass transport interiors which released more toxic products during combustion. This work explores the cytotoxicity of selected chemicals and smoke derived from materials combustion. A selection of polymers and fiberglass reinforced polymer (FRP) composites used in building and railway carriage interiors including: polyethylene (PE), polypropylene (PP), polycarbonate (PC), polymethyl methacrylate (PMMA), polyvinyl chloride (PVC), melamine plywood, and two FRPs were studied. A small scale laboratory fire test using a vertical tube furnace was designed for the generation of combustion products. The volatile organic compounds were identified using ATD-GCMS (Automatic Thermal Desorption-Gas Chromatography Mass Spectrometry). The in vitro techniques were developed for human cells exposure to fire effluents including the indirect (impinger) and direct (air/liquid interface using Harvard Navicyte Chamber) exposure. Cytotoxic effects were assessed based on cell viability using a range of in vitro assays. Human skin tissue was also used as preliminary study to assess the toxic effects at the tissue level. A minor change in the cellular function of the skin from the exposure of PMMA combustion products was observed. The combustion study was conducted under different burning stage of fire: non-flaming and flaming combustion. Results suggested that PVC was the most toxic material for both non-flaming (IC50 1.24 mg/L) and flaming combustion (IC50 1.99 mg/L). The degree of toxicity generated depends on the fire stage: non-flaming or flaming combustion. Some materials revealed to be more toxic under flaming combustion (PP, PC, FRPs), whilst others (PVC, PMMA, PE, and melamine plywood) appear to be more toxic under non-flaming combustion. A strong correlation was shown between the change in toxicity as measured by IC50 and TLC and the change in concentration of volatile organic compounds (VOCs) and particulates. A comparison between in vitro data versus published in vivo combustion data indicated the in vitro results to be more sensitive than animal toxicity data. The outcome of this study has the potential for an alternative method to current fire toxicity standard, whilst providing more accurate toxicity information for fire safety professionals, materials manufacturer, building designers and consumer safety data.

Thesis (Ph. D.)--University of Adelaide, 1989. / Includes bibliographical references (leaves 116-138).

Thesis (Ph.D.)--University of Adelaide, Dept. of Clinical and Experimental Pharmacology, 1999. / Erratum tipped in before chapter 1. Bibliography: leaves 226-248.