Thesis (M.S.)--University of Missouri-Columbia, 2003. / Typescript. Includes bibliographical references (leaves 101-107). Also available on the Internet.

Thesis (M.S.)--University of Missouri-Columbia, 2003. / Typescript. Includes bibliographical references (leaves 101-107). Also available on the Internet.

This thesis presents a modeling program to obtain equilibrium information for a fluorescent system. Determining accurate dissociation constants for equilibrium processes involving a fluorescent mechanism can prove to be quite challenging. Typically, titration curves and non-linear least squares fitting of the data using computer programs are employed to obtain such constants. However, these approaches only consider the total fluorescence signal and often ignore other energy transfer processes within the system. The current model considers the impact on fluorescence from equilibrium binding (viz., metal-ligand, ligand-substrate, etc.), quenching and resonance energy transfer. This model should provide more accurate binding constants as well as insights into other photonic processes. The equations developed for this model are discussed and are fit to experimental data from titrimetric experiments. Since the experimental data are generally in excess of the number of parameters that are needed to define the system, fitting is operated in an overdetermined mode and employs error minimization (either absolute or relative) to define goodness of fit. Examples of how changes in certain parameters affect the shape of the titrimetric curve are also presented. The detection of metal ions is very important, causing a need for the development of a metal ion sensor that provides selectivity, sensitivity, real-time in situ monitoring, and a flexible design. In order to be able to perform in situ monitoring of trace metal ions, FRET-pair labeled peptides were attached to a Tentagel[trademark] resin surface. After soaking in nonmetal and metal solutions (pH = 7.5), the resin beads gave an enhanced response in the presence of Hg²⁺ and Zn²⁺. Using a t-test, the signals of the beads that were soaked in a solution of each of these metal ions (and that of Cd²⁺) were determined to be significantly different from beads soaked in a solution without metal. However, the standard deviation between a set the beads was too large in order to differentiate a bead that was soaked in nonmetal solution versus one soaked in a metal containing solution. / text

The focus of this work is to synthesize and immobilize novel rigid tetraphosphine linkers via the formation of phosphonium groups and by direct adsorption of tetraphosphine salts on oxide surfaces. These methods offer the possibility to study the mechanism of the phosphonium formation in more detail by utilizing solid-state NMR spectroscopy. It has also been a point of interest to study the linkers and catalysts under realistic conditions, in the presence of solvents. Therefore, HRMAS (high-resolution magic angle spinning) NMR spectra of several phosphonium salts, adsorbed on SiO2, have been studied. This technique allows one to probe the leaching and mobility of the linkers on the surface. The mobilities of the linkers and the catalysts are crucial factors for the performance and design of the immobilized catalysts. Finally, since the exact mode of binding to the surface is unknown and is being discussed in the literature, for example, as hydrogen bonding between the F atoms in BF4- and surface silanol protons, the influence of the counteranion on the binding of phosphonium salts on silica surfaces is of utmost interest. For surface mobility studies a monolayer of phosphonium salts on the silica surface, both without solvent and in the presence of solvent, has been studied via 31P and 2H CP/MAS and HRMAS. Our findings show that the integrity of the tetraphosphine scaffold linkers is based upon how it is immobilized. The best system is formed when the phosphine is immobilized on the SiO2 support by adding Cl(CH2)3Si(OEt)3 to the reaction mixture. In this way, phosphonium salts are obtained, which are bound to the surface irreversibly by electrostatic interactions, as proven by solid-state NMR. In addition, leaching and mobility studies prove that the solvents play a crucial role, and the more polar solvents, such as DMSO, lead to the most extensive leaching due to the solvents' strong adsorption on the SiO2 surface. Leaching studies also show that the counteranion has an influence on the binding of the phosphoniumn salts on the SiO2 surface. The leaching proceeds in the following manner: BF4- > I- > Br- > Cl-. This is an indication that there is an additional interaction between the anion and, most probably, the surface silanol protons.

Microarray technology like that of recombinant DNA and the polymerase chain reaction is a foundational component of modern biotechnology. There are many aspects in the manufacture of a DNA chip and each serves as a contributing variable to the overall performance of the device. Commercial production of microarrays commenced before a basic understanding of the physical and chemical processes that govern the many variables was attained and the role of each on the performance of microarrays was understood. The consequence of this has been non-optimal performance of this technology and variable results from microarray analyses. Recent studies have shown that part of the variability in the use of commercially available microarrays relates to insufficient control of the surface chemistry within a microarray spot and between spots. Although the ideal characteristics of a microarray surface have been identified, existing surfaces and the ongoing proliferation of alternative ones do not address these sufficiently in order to reduce the sources of error arising from the surface of a microarray. Hence, the application of physico-chemical techniques in the development of microarrays surfaces can assist in improving the performance of these devices. / Thesis (PhDApSc(MineralsandMaterials))--University of South Australia, 2006.

Thesis (Ph.D.)--University of Tulsa, 1990. / Bibliography: leaves 125-132.

Thesis (M.S.)--University of North Texas, Dec., 2007. / Title from title page display. Includes bibliographical references.

Thesis (Ph.D.)--University of Nebraska-Lincoln, 2006. / Title from title screen (site viewed Oct. 10, 2007). PDF text: 234 p. : ill. (some col.) UMI publication number: AAT 3259631. Includes bibliographical references. Also available in microfilm and microfiche formats.

Thesis (Ph. D.)--University of Washington, 2006. / Vita. Includes bibliographical references (leaves 213-235).

Made available in DSpace on 2015-03-03T11:52:37Z (GMT). No. of bitstreams: 0 Previous issue date: 2014-07-25Bitstream added on 2015-03-03T12:06:21Z : No. of bitstreams: 1 000806886_20160725.pdf: 581026 bytes, checksum: 4c55faecb6d2b9cbebcf0fed8076771a (MD5) Bitstreams deleted on 2016-07-25T13:17:27Z: 000806886_20160725.pdf,. Added 1 bitstream(s) on 2016-07-25T13:18:38Z : No. of bitstreams: 1 000806886.pdf: 2412685 bytes, checksum: 76a763d7dfe3317535d6f9ec19a7cd78 (MD5) / As endoglicanases EC 3.2.1.4 são enzimas capazes de hidrolisar as ligações glicosídicas ?-1,4 da celulose, resultando na liberação de glicose, celobiose e celo-oligossacarídeos. Empregadas mundialmente em diversos processos industriais, por exemplo, como amaciante de tecidos de algodão e bioestonagem de jeans, na extração de sucos de frutas, na adição em detergentes comerciais, na fabricação de cerveja, e na produção de papel e de etanol. Atualmente, há um grande interesse em enzimas que hidrolisem biomassa lignocelulósica para obtenção de etanol de segunda geração. A imobilização de enzimas em matrizes sólidas oferece muitas vantagens, entre as quais, reuso da enzima, a fácil separação do produto e o aumento da estabilidade operacional. Os objetivos deste trabalho foram: produzir CMCases secretadas por Aspergillus niger e Humicola grisea var. thermoidea em cultivo sólido e submerso; imobilizar CMCases em suporte agarose com diferentes ativações químicas; determinar a estabilidade térmica e as propriedades cinéticas dos derivados obtidos, comparando-os com as enzimas livres; avaliar a capacidade de reuso dos derivados ativos e estáveis e analisar qualitativamente o produto de hidrólise dos substratos celulósicos. O fungo A. niger secretou grandes quantidades de CMCases, 34,1 U.mg-1, em meio Vogel, utilizando pó de bagaço de cana-de-açúcar como fonte de carbono. O pH 5 foi determinado como o ótimo para a enzima, apresentando instabilidade ao pH 10. Com a utilização de aditivos estabilizante, a trealose a 10% (m/v), manteve, em pH 10, 80% de atividade residual, por 25 horas. Em relação à temperatura, apresentou uma faixa ampla de atividade entre 45°C a 75°C, tendo como temperatura ótima 65°C. O derivado enzimático que ofereceu melhor estabilidade foi aquele em que a imobilização foi conduzida juntamente com o substrato carboximeticelulose (CMC 1%), em... / The endoglucanases EC 3.2.1.4 are enzymes that hydrolyze the ?-1, 4 glycosidic linkages of the cellulose producing glucose, cellobiose and cello-oligosaccharides. Used worldwide in many industrial processes such as fabric softener and bioestonagem cotton jeans, extraction of fruit juices, in the addition of commercial detergents, in brewing, and the production of paper and ethanol. Currently, there is great interest in enzymes that hydrolyze lignocellulosic biomass to obtain second-generation ethanol. The immobilization of enzymes on solid arrays provides many advantages as the enzyme reuse, easy separation of the product and increased operational stability. The aims of this study were to produce secreted: CMCases produce secreted by Aspergillus niger and Humicola grisea var. thermoidea in solid and submerged cultivation; CMCases immobilized on agarose support with different chemical activations; determine the thermal stability and kinetic properties of the derivatives obtained comparing them with the free enzyme; evaluate the reuse capacity assets and stable derivatives and qualitatively analyze the product of hydrolysis of cellulosic substrates. The fungus A. niger secreted large amounts of CMCases, 34.1 U.mg-1 amid Vogel, using powdered sugarcane bagasse as a carbon source. The pH of 5 was determined as the optimum for the enzyme, presenting instability to pH 10. With the use of stabilizing additives, the 10% trehalose (w / v), kept at pH10, 80% residual activity for 25 hours. Regarding temperature there was a broad activity range from 45 °C to 75 °C and the optimum temperature as 65 °C. The enzyme derivative which offered better stability was one in which immobilization was conducted with the carboxymethycellulose substrate (1% CMC) in agarose support Glutaraldehyde (70% of reactive groups), preserving catalytic activity of 35% at 60 °C for 250 hours. Through qualitative TLC analysis, it...