Thesis (M.Sc.) - Carleton University, 2001. / Includes bibliographical references (p. 86-90). Also available in electronic format on the Internet.

Thesis (Ph. D.)--University of Chicago, 1938. / Reproduced from type-written copy. "Private edition, distributed by the University of Chicago libraries, Chicago, Illinois." Includes bibliographical references.

Thesis (Ph. D.)--University of Chicago, 1929. / Lithoprinted. "Private edition, distributed by the University of Chicago libraries, Chicago, Illinois."

Thesis (Ph. D.)--Ohio State University, 2005. / Title from first page of PDF file. Document formatted into pages; contains xvii, 259 p.; also includes graphics (some col.). Includes bibliographical references (p. 233-259). Available online via OhioLINK's ETD Center

Thesis (Ph. D.)--University of Washington, 2007. / Vita. Includes bibliographical references (leaves 145-152).

The syntheses of siloxyl and hydroxyl chain end functionalized polystyrene and poly(methyl methacrylate) by Atom Transfer Radical Polymerization (ATRP) were effected by the following methods: (a) α-Siloxyl functionalized polymers were prepared in quantitative yields via a one-pot ATRP synthesis method for the polymerization of styrene or methyl methacrylate using a new siloxyl functionalized initiator adduct, formed in situ by the reaction of (1-bromoethyl)benzene with 1-(4-t-butyldimethylsiloxyphenyl)-1- phenylethylene in the presence of CuBr/bpy or CuBr/PMDETA as catalysts in diphenyl ether at 90 -110 oC. The polymerizations proceeded via controlled living radical polymerization methods and α-siloxyl functionalized polymers with predictable number average molecular weights (Mn = 1.8 x 103 - 17.40 x 103 g/mol), narrow molecular weight distributions (Mw /Mn = 1.03 - 1.41) and regiospecificity of the functional groups were obtained in quantitative yields. Similarly, the one-pot ATRP synthesis method for the preparation of α-bis(siloxyl) functionalized polymers were effected by the initiation of styrene or methyl methacrylate polymerization with a new bis(siloxyl) functionalized initiator adduct, formed by the in situ reaction of 1,1-bis(4-t-butyldimethylsiloxylphenyl)- ethylene with (1-bromoethyl)benzene in the presence of CuBr/bpy or CuBr/ PMDETA as catalytic systems in diphenyl ether at 90 -110 oC. Each polymerization reaction proceeded via a controlled living fashion to afford quantitative yields of the corresponding α-bis(siloxyl) functionalized polymers with predictable number average molecular weights (Mn = 1.7 X 103 - 15.00 x 103 g/mol), narrow molecular weight distributions (Mw /Mn = 1.03 - 1.35) and good control of chain end functionality. The acid catalyzed hydrolysis of α-siloxyl and α-bis(siloxyl) chain end functionalized polymers afforded the corresponding α-hydroxyl and α-bis(hydroxyl) chain end functionalized polymers, respectively. Polymerization kinetic data was employed to determine the controlled/living character of each ATRP reaction leading to the formation of different siloxyl functionalized chain end functionalized polymers. Polymerization kinetic measurements show that the polymerization follows first order rate kinetics with respect to monomer consumption and the number average molecular weight increases with percentage monomer conversion, resulting in the formation of polymers with narrow molecular weight distributions. Thin layer chromatography (TLC), 1H and 13C Nuclear Magnetic Resonance Spectrometry (NMR), Fourier Transform Infrared Spectroscopy (FTIR), Size Exclusion Chromatography (SEC), Gas Chromatography (GC) and non - aqueous titrations were used to determine the structures and purity of the siloxyl functionalized initiator precursors as well as the siloxyl and hydroxyl functionalized polymers.

The goals of this thesis were to design and synthesize new stable radicals and to study their properties. The attempted synthesis of new stable thioaminyl, verdazyl, and dioxadiazinyl radicals is described. Successfully prepared radicals were characterized by spectroscopic methods. The synthesis of new thioaminyl radicals and diradicals was attempted. Preparation of thioaminyl precursors, the sulfenamides, was accomplished with sulfenyl chlorides and amines. Oxidation with DDQ yielded radicals which decomposed back to the sulfenamides within 1–2 minutes. A bis(sulfenamide) was synthesized using a sulfenyl chloride and an appropriate bis(amine). The structure of the bis(sulfenamide) was confirmed by NMR spectroscopy and x-ray crystallography. Oxidation of the bis(sulfenamide) to the thioaminyl diradical was unsuccessful. New phosphaverdazyl radicals were prepared and studied using EPR spectroscopy. The phosphaverdazyl precursors, the tetrazines, were prepared from the corresponding bis(hydrazides). The tetrazines were oxidized with benzoquinone to yield phosphaverdazyls. The phosphaverdazyls prepared do not share the same level of stability as the parent carbon-based verdazyls; they slowly decompose back to tetrazines. Incorporation of phosphorus into the verdazyl core has several effects on the properties of the radical relative to the parent verdazyl system. Through a combination of EPR and computational studies, it was concluded that the geometry of the verdazyl ring and the electronic nature at phosphorus appear to be sensitive to the nature of the substituents attached to phosphorus. Exocyclic “spin-leakage” was observed for one phosphaverdazyl, which can be rationalized using a spiroconjugative mechanism. The phenomena of spiroconjugation was further explored through the synthesis of a phosphaverdazyl derivative attached to phosphazene in a spirocyclic manner. Synthetic routes to the hitherto unknown dioxadiazinyl system were explored. An intermediate hydroxyamidoxime was synthesized and fully characterized. Cyclization reactions of the hydroxyamidoxime to putative dioxadiazines were carried out using aldehydes and a ketone. The cyclization products could not be unambiguously assigned. The cyclization products can be rationalized as the desired dioxadiazine or the 5-membered oxadiazolidine. One derivative was oxidized to a persistent radical, the EPR of which is consistent with a nitroxide structure. / Graduate

Orientador: Débora Cristina Damasceno / Resumo: Early embryos recovered from diabetic rats show increased number of blastomeres undergoing apoptosis and decreased total number of blastomeres, suggesting impaired litter size and newborn weight. This might increase the chances of metabolic disorders in adulthood of these animals. Since diabetes-induced hyperglycemia impairs the redox balance, the aim was to evaluate the embryonic oxidative stress status before the implantation in order to identify whether there are differences in levels of oxidative stress in early embryos from diabetic dams. Thus, we hypothesized the decreased cell number found in early embryos recovered from diabetic rats is due to the low embryonic ability to maintain their own redox balance. Our study shows that rats with streptozotocin-induced mild and severe diabetes present impaired redox status in early pregnancy. This maternal unbalance directly influences the embryonic redox status, reflecting the increased reactive oxygen species in the morula stage. We also showed that regardless of hyperglycemic level the embryos trigger defense mechanisms involved in the excessive free radical scavenging as an attempt to survive. Nevertheless, the success of this defense mechanism seems to depend on maternal hyperglycemia, highlighting the importance of the programmed pregnancy as well as appropriate medical care starting in early stages of human diabetic pregnancy. / Doutor

O ácido 3-indol acético (IAA), um conhecido hormônio de planta, e seu metabólito indol-3-carboxialdeído (ICA) têm sido envolvidos em várias patologias humanas como fenilcetonúria e doenças renais. A formação de espécies reativas de oxigênio e de estados eletronicamente excitados, como o oxigênio singlete (1O2) e a carbonila triplete (R2-C=O*), durante a oxidação aeróbica do IAA catalisada por peroxidase de raiz forte (HRP) têm sido relacionada com efeitos citotóxicos do IAA. Nossos resultados indicam aumento na formação de 8-oxo-7,8-dihidro-2\'desoxiguanosina (8-oxodGuo) após o tratamento da base com o sistema IAA/HRP/O2 in vitro, medido por um detector eletroquímico acoplado a um sistema de cromatografia líquida de alta performance (HPLC-EC). O tratamento de células de mamíferos (CV1-P e neutrófilos) com este sistema induziu o aumento na formação de 8-oxodGuo no DNA, assim como o aumento no nível de lipoperoxidação das células CV1-P quando comparadas ao controle. Detectamos a presença do adulo 1,N2-etenodesoxiguanosina em DNA de neutrófilos submetidos ao IAA. Portanto, neste estudo, apresentamos evidências de danos em biomoléculas promovidos pelo sistema IAA/HRP/O2. / Indole-3-acetic acid (IAA), a2 plant hormone, and its metabolite indole-3-carboxialdehyde (ICA) has been involved in several human pathologies as phenylketonuria and renal diseases. Formation of reactive oxygen species and electronically excited states as singlet oxygen (1O2) and triplet carbonyl (R2-C=O*), during the aerobic oxidation catalyzed by horseradish peroxidase (HRP) has been reported to be involved in the IAA cytotoxic effects. Our results show an increase in the formation of 8-oxo-7,8-dihydro-2\'deoxiguanosine (8-oxoxdGuo) after IAA/HRP/O2 system treatment in vitro as inferred from high performance liquid chromatography-electrochemical detection (HPLC-EC) measurements. Treatment of mammalian cells (CV1-P and neutrophils) with the system induces 8-oxoxdGuo formation in DNA as well increased levels of lipid peroxidation CV1-P cells when compared to controls. The 1,N2-etenodeoxyguanosine was detected in neutrophils DNA. Therefore, in this study, we presented evidence of biomolecule damage by IAA/HRP/O2 system.

Dissertação(mestrado) - Universidade Federal do Rio Grande, Programa de Pós-Graduação em Engenharia e Ciência de Alimentos, Escola de Química e Alimentos, 2009. / Submitted by Caroline Silva (krol_bilhar@hotmail.com) on 2012-08-27T19:37:20Z No. of bitstreams: 1 dissertao cintia_defesa.pdf: 808863 bytes, checksum: d9ab57cfdbf88e2f2fc31318462a352c (MD5) / Approved for entry into archive by Bruna Vieira(bruninha_vieira@ibest.com.br) on 2012-12-01T16:33:40Z (GMT) No. of bitstreams: 1 dissertao cintia_defesa.pdf: 808863 bytes, checksum: d9ab57cfdbf88e2f2fc31318462a352c (MD5) / Made available in DSpace on 2012-12-01T16:33:40Z (GMT). No. of bitstreams: 1 dissertao cintia_defesa.pdf: 808863 bytes, checksum: d9ab57cfdbf88e2f2fc31318462a352c (MD5) Previous issue date: 2009 / As propriedades nutricionais da microalga Spirulina têm sido relacionadas com possíveis propriedades antioxidantes, caracterizando-a no âmbito dos alimentos funcionais. Os antioxidantes são compostos que atuam inibindo e/ou diminuindo efeitos desencadeados pelo estresse oxidativo, conservando a harmonia entre a produção fisiológica de radicais livres e sua detoxificação. Objetivou-se avaliar o potencial antioxidante da microalga Spirulina e seu principal pigmento, a ficocianina, em situações de estresse oxidativo induzido. Foram realizados estudos com células da levedura Saccharomyces cerevisiae, submetidas a estresse oxidativo pela adição de 1,1´-dimetil-4,4´-bipiridilo (paraquat) nas concentrações 0, 10 e 15 mM, avaliando o potencial antioxidante da Spirulina através da sobrevivência celular (plaqueamento) e da lipoperoxidação (índice de substâncias reativas ao ácido tiobarbitúrico, TBA). Também foi avaliado o efeito protetor da Spirulina e/ou da ficocianina em córtex cerebral de ratos submetidos a estresse oxidativo por administração de glutamato monossódico ou por situação de pânico. No córtex dos animais foram avaliados os índices de TBA e a atividade específica das enzimas superóxido dismutase (SOD) e catalase (CAT). O uso do herbicida paraquat nas concentrações 10 mM e 15mM, diminuiu a sobrevivência celular da levedura em relação ao controle (39,4 % e 17,1%, respectivamente) e aumentou significativamente a lipoperoxidação (p≤0,05). O agente estressor glutamato monossódico provocou aumento significativo (p≤0,05) da lipoperoxidação e diminuição significativa (p≤0,05) das atividades específicas das enzimas SOD e CAT no córtex cerebral dos ratos. O estresse por situação de pânico também provocou alterações significativas (p≤0,05) no córtex dos ratos, aumentando a peroxidação lipídica e a atividade da enzima SOD e diminuindo a atividade da enzima CAT. O uso da Spirulina, bem como da ficocianina, atenuaram os efeitos deletérios decorrentes do estresse oxidativo induzido em células de leveduras e em córtex de ratos, mantendo os parâmetros dos grupos tratados com estressor e antioxidante estatisticamente iguais aos do grupo controle. Estes resultados contribuem com a caracterização da microalga no âmbito dos alimentos funcionais antioxidantes. / The nutritional properties of the microalgae Spirulina have been related with possible therapeutical properties, characterizing it in the scope of functional and nutraceutical foods mainly had its antioxidant potential. The antioxidant substances are composites that act inhibiting and/or decreasing the effect unchained of oxidative stress, conserving the balance between physiological production of free radicals and its detoxification. It was objectified to evaluatethe antioxidant potential of the microalgae Spirulina and its main pigment, the phycocyanin, in situation of oxidative stress induced. studies whit cells of Saccharomyces cerevisiae yeast had been carried, submitted oxidative stress for the addition of 1,1´-dimetil-4,4´-bipiridilo (paraquat) in concentrations 0, 10 and 15 mM, evaluating the antioxidant potential of the Spirulina throught the cellular survival and reactives substances index to the tiobarbituric acid (TBA). Also was evaluated the protective effect of the Spirulina and phycocyanin, in cerebral cortex of rats submitted to oxidative stress induced for glutamate monosodic administration or panic situation. In the cortex of animals the TBA index, and activity of enzymes superoxide dismutase (SOD) and catalase (CAT) had been evaluated. The use of paraquat in concentrations 10 mM and 15mM, decreased yeast cellular survival in relation to the control (39.4% and 17.1%, respectively) and increased the lipoperoxidation significantly (p≤0,05). The estressor agent glutamate monossodic provoked significant increase (p≤0,05) in lipoperoxidation and significant reduction (p≤0,05) of enzymes SOD and CAT in the cerebral cortex of the rats. The oxidative stress for panic situation also provoked significant alterations (p≤0,05) in the cortex of the rats, increasing the lipidic peroxidation and the activity of enzyme SOD and diminishing the activity of enzyme CAT. The use of the Spirulina, as well as phycocyanin, had attenuated the decurrent deleterious effect of oxidative stress induced in cells of yeast and in cortex of rats, keeping the parameters of the groups dealt with statistical equal stressor and antioxidant substance to the ones of the group has controlled. These results contribute with the characterization of the microalgae in the scope of antioxidant functional foods.