A variety of biological and organic reaction mechanisms are studied using powerful tools from experimental and theoretical chemistry. These tools include the precise measurement of kinetic isotope effects (KIEs) and the use of theoretical calculations to predict KIEs as well as determine factors that contribute to reaction acceleration and selectivity. Theoretical analysis of the Swain-Schaad relationship involves the prediction of a large number of isotope effects and establishes the semiclassical boundaries of the relationship. Studies on the mechanism of oxidosqualene cyclase involve the determination of a large number of precise KIEs simultaneously. Transition state models for the Sharpless asymmetric epoxidation have been developed that explain the versatility, high selectivities, and ligand accelerated catalysis of the reaction. Theoretical predictions on the proposed enzymatic mechanism of flavin dependent amine oxidation suggest a hydride transfer mechanism and rules out mechanisms involving covalent intermediates. Finally, a theoretical analysis of Diels-Alder reactions successfully describes the unexpected exo selectivity in some of these reactions.

No description available.

No description available.

A full length cDNA clone of Brassica napus 3-oxoacyl-ACP reductase (β-ketoacyl-ACP reductase; E.C. 1.1.1.100; βKR) and the Escherichia coli gene for the same enzyme, have been over-expressed in E. coli. Both the Brassica napus seed and Escherichia coli βKR proteins have been purified by a rapid two-step, single chromatography matrix method. Glutaraldehyde cross-linking studies show the plant βKR is expressed as a tetramer and the E. coli enzyme is expressed as a dimer. The secondary structure of the two proteins was predicted via analysis of circular dichroism spectra, which also show dilution dependent unfolding of a-helical structure in the plant enzyme, a possible explanation for the dilution inactivation of βKRs. Ultrafiltration substrate binding studies and a bireactant initial velocity study show that Brassica napus βKR employs a fixed order ternary complex mechanism with NADPH binding to the enzyme first. One-dimensional western blot analysis indicates two isoforms of βKR (28 kDa and 31 kDa) in crude B. napus seed extracts. Further analysis using two- dimensional western blots demonstrates the presence of four major isoforms. Comparison with 2D blots from B. campestris suggests that one of the major isoforms has originated from that source. The crystal structure of the E. coli βKR enzyme is also discussed.

ix, 109 leaves : ill., tables ; 30cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.1976) from the Dept. of Physical and Inorganic Chemistry, University of Adelaide

This research examines the zone between environment and interior, the architectural façade, for the potential to develop a new form of composition based on kinetic pattern. Within contemporary architecture there is a growing interest in kinetics. Intelligent façades for example, manifest kinetics in the form of a responsive skin that adapts to changing environment conditions and user occupancy, continuing the trajectory of functionalism. Media façades by contrast, are driven by an interest in the recasting of architectural surface as a zone of interactivity, with the potential to engage users with public art works or embed socio-cultural information. Regardless of the design intent, the emerging field of kinetic façades offers the challenge of developing a sophisticated approach to the design of motion. As evidenced by a review of theory and practice, there is a lack of fundamental knowledge about the possibilities offered by kinetics. / Through the lens of morphology, this thesis explores the possibilities of kinetic composition afforded by façades in motion. The emphasis is on the underlying structure of kinetic form, independent of physical scale or materiality. Kinetics is defined in spatial terms: actual movement through geometric transformation in space (translation, rotation, scaling); or through controlling material properties of elasticity and mass to produce movement. Composition is analyzed in terms of pattern, defined as the relative movement of individual kinetic parts in time and space - the way in which multiple singular kinetic events cluster, or propagate, across a facade over time. A morphology of pattern is developed by three interrelated questions. What design variables influence kinetics, what is the theoretical range, and what nomenclature may robustly describe a morphology of pattern? / An original framework for conceiving design variables is proposed. The framework revolves around diverse approaches to data sampling and control systems, alongside the typical architectural emphasis on the design of the physical components. These three interrelated design activities are conceived in terms of ‘decision planes’. Specification of variables on each plane and in relation to time, determine the spatio-temporal limits, or what is termed as the ‘variable space’, from which patterns will emerge. / This conceptual framework has been used to structure a methodical series of computer animations, which explore range of pattern. In a similar vein to the tradition of façade study drawings, a diagrammatic approach to animation has been developed. The adoption of a non-realistic mode of representation is intended to focus attention on ‘movement itself’, independent of physical scale, materiality or figurative associations. Through analysis and discussion of the animations, it is proposed that morphology of kinetic pattern is robustly described through a nomenclature based on state change. It is proposed that three recognizable states reoccur-waves, folds and fields. State change is based on the principle of internal variance within these three simple states, and intermediate states that allow transition by degree and kind. Similar to the nomenclature for describing clouds, this provides a robust and extendable approach, allowing multiple intermediate states to be conceived in relation to the wave, fold and field definitions. / The framework for conceiving variables that influence pattern and the state change morphology provide the means to improve understanding in the particular realm of kinetic façade composition. The framework is presented in generic form and a particular instance is developed based on an analysis of key references. This provides a model to conceive the multiple variables that influence kinetic composition, while the morphology provides a low resolution map for designers, identifying the most distinctive forms and providing a scaffold for research by design. Further work on extending these contributions to knowledge is outlined, including the description of a simulation environment calibrated to the physical constraints of materials and technology.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1961. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis--University of Wisconsin--Madison. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaf 139).

Thesis (Ph. D.)--University of Wisconsin--Madison, 1955. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 129-131).

Thesis (Ph. D.)--University of Wisconsin--Madison, 1976. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 211-217).