title: Characterization and phosphorylation site mapping of human pleckstrin

contributor:
Harley, Calvin B.
Biochemistry

subject: Biochemistry, Biophysics, and Structural Biology

abstract:
Pleckstrin is the major substrate of PKC in activated platelets, therefore a role for pleckstrin in mediating platelet responses such as secretion has been widely hypothesized. Previous cloning of the pleckstrin gene indicated that it encoded a unique protein sequence containing no obvious structural, catalytic or otherwise functional motifs, apart from several candidate PKC phosphorylation sites and homology between the Nand C terminal domains.

The role of pleckstrin in mediating cytoskeletal changes that occur during platelet activation and secretion was investigated based on published data implicating pleckstrin in directly inhibiting actin polymerization in its unphosphorylated fonn. There were no significant effects on the kinetics of actin polymerization in vitro using recombinant pleckstrio or pleckstrin purified from platelets. In accordance with this observation, overexpression of pleckstrin in COS cells did not appear to affect the subcellular distribution or ftlament length of actin compared to uninfected cells. Also, pleckstrin did not significantly co-localize with actin prior to or after exposure to phorbol 12-myristate 13- acetate (PMA) concentrations known to induce maximal phosphorylation of pleckstrin. It was therefore concluded that pleckstrio does not playa direct role in regulating actin polymerization.

Based on limited sequence homology to dynamin (which is involved in endocytosis), I postulated that pleckstrio might regulate vesicle motility, a key requirement for platelet degranulation. Pleckstrin immunofluorescently labelled in transfected COS cells did not appreciably co-localize with either ER or Golgi structures, the precursors of secretory vesicles, or with microtubules, however some punctate fluorescence was observed that co-localized with the ER. Immunfluorescent detection of pleckstrin in peripheral blood cells indicated that pleckstrin is most highly abundant in platelets, moderately expressed in polymorphonuclear cells and absent or lowly expressed in lymphocytes.

Pleckstrin's prevailing characteristic, its phosphorylation, was examined in greater detail. Wild-type recombinant pleckstrin overexpressed in COS cells displayed a 5 fold stimulation of ³²P incorporation in response to PMA treatment. To exclude the possiblity of phosphorylation by kinases other than PKC, the effect of staurosporine on inhibiting pleckslrio phosphorylation was examined. Staurosporine inhibited pleckstrin phosphorylation in the heterologous COS cell system with an IC₅₀ = 10 nM. similar to that reported to inhibit pleckstrin phosphorylation in the platelet. Additionally. identical phosphopeptide maps were generated of wild-type pleckslrio isolated from HL-60, HEL or transfected COS cells indicating that pleckstrin expressed recombinantly in COS cells was by all known measures functionally competent. However, a pleckstrin mutant deleted for 42 residues including the most probable phosphorylation sites was de-regulated for phosphorylation, displaying a high basal level of phosphorylation, no response to PMA, and increased association with cytoskeletal or membraneous components.

To precisely map the phosphorylation sites of pleckstrin. 8 serine or threonine residues were converted to alanine using site-directed mutagenesis. Two of these mutants, S113A and SI17 A, consistently displayed a lower level of PMA-induced hosphorylation compared to the wild-type protein. Tryptic phosphopeptide maps of three pleckstrin mutants, S1l3A, T1l4A and S1l7A indicated that phosphorylation of pleckstrin occurs almost exclusively on SI13 and S117; these sites accounted for 46 and 52% respectively of the incorporated phosphate. A minor, variable amount of phosphorylation on TI14 was observed. These phosphorylation sites were confirmed by phosphopeptide mapping synthetic peptides corresponding to residues 108-120 of pleckstrio, and by performing phosphoamino acid analysis on the tryptic phosphopeptides generated in these maps.

Lastly, overexpression of each of the phosphorylation site mutants of pleckstrin in COS cells indicated that one of them, S 113A, might possess a dominant activity that perturbs membrane/cytoskeletal structures. This mutant induced large, semi-circular ruffles or "lobes" in transfected COS cells in two independent experiments.

In conclusion, the function of pleckstrin is still entirely unknown. It is quite clear however that pleckstrin is an excellent substrate for PKC. Phosphorylation of pleckstrin likely affects its function, a hypothesis supported in this work by the unusual phenotype of COS cells overexpressing the Sll3A mutant.

abstract: Doctor of Philosophy (PhD)


title: Synthesis and thermolysis of 2,2-dioxy-5,5-dimethyl-delta(3)-1,3,4-oxadiazolines: Dioxycarbenes and their reactions

contributor:
Warkentin, John
Chemistry

abstract: Oxadiazolines (I-III), which are novel thermal sources of dioxycarbenes, were synthesized by the exchange method using the acetoxy analogue. The thermal fragmentation of 2,2-dialkoxy oxadiazolines was established to be unidirectional. At $100\sp\circ$C, oxadiazolines (I) decomposed forming nitrogen, acetone, and alkoxymethoxycarbenes as deduced from the identification of the carbene dimers MeO(OR)C=C(OR)OMe.* On the other hand, thermolysis of the aryloxymethoxy oxadiazolines (II) was a multidirectional fragmentation process, with the aryloxymethoxycarbene formation as the major course. A competitive fragmentation afforded the methyl aryl carbonate and diazopropane. The thermal chemistry of the benzyloxymethoxy oxadiazolines (III) is similar to that of the aryloxymethoxy analogue (II). The oxadiazoline (III) loses N$\sb2$ thermally, and also produces acetone and the benzyloxymethoxycarbene via the carbonyl ylide. In addition, the carbene rearranges producing the corresponding ester via 1,2-benzyl group migration to the carbene centre. This rearrangement is a substituent dependent process which is enhanced by electron donating groups. The intermolecular reactions of aryloxymethoxycarbene (IV) with alkynes resulted in a regioselective generation of a 3,3-dioxyvinylcarbene (V or VI). This carbene can either undergo an intramolecular nucleophilic aromatic substitution and/or further reaction with the alkyne. The reaction pathway of (V or VI) is strongly dependent on the nature of the substituent $\rm(R\sp\prime).$* Finally, the aryloxymethoxycarbenes were trapped inter- and intramolecularly via OH insertion reactions. ftn*Please refer to dissertation for diagrams.

abstract: Doctor of Philosophy (PhD)


title: Internal surface coating and photochemical modification of polypropylene microfiltration membrane

contributor:
Dickson, J.M.
Chemical Engineering

subject:
Chemical Engineering
Chemical Engineering

abstract:
Membrane surface modification is of interest to most membrane scientists because the surface properties of most commercial membranes are often nonoptimal for particular applications. This thesis focuses on the further development of a thin film coating on the internal surface of polypropylene microfiltration membrane. A modified interfacial polymerizatIon of 1,6-naphthalene disulfonylchloride containing a photoactive diazoketone (DK) group on the side chain and 1,8-octanediamine is studied. Various fabricatIon conditions including concentration of monomers, organic solvent selection, crosslinking agent, selection of an acid acceptor and reaction time were investigated. The choice of organic solvent was found to be critical for obtaining an even, smooth coating layer without significantly changing the membrane morphology. Mass of the polysulfonamide coating layer was typically 10-15 wt% of the base membrane. The coating layer at the membrane internal surface demonstrated a high stability to Soxhlet extracting using CHCl₃ for 48 hours.

A mechanism of this new type of interfacial polymerization is qualitatively proposed, and investigated experimentally. The first reported study of end-group analysis and molecular weight measurement of coating polysulfonamide provided a solid ground to evaluate the hypothesis. Most results from experiments either strongly support the proposed mechanism or can be reasonably interpreted by the proposed mechanism. The mechanistic study defines the most important principles of this new type of interfacial polymerization which can be varied to control the coating process, and gives a better understanding of this new coating technology.

General applicability of this coating technology was tested by applying this technology to polyester and polyamide. The results indicate that this new technology is generally applicable and can be used to coat condensation polymers to the internal membrane surface as an even thin layer, without significantly changing the morphology of the polyolefin microfiltration membranes.

The chemical functionality of polysulfonamide coated membrane surface could be further modified via photochemical transformation of the diazoketone group contained in the coating polysulfonamide, in the presence of an appropriate medium. Thus, membranes containing indene acid, glycolic acid, bromoethyl ester, and polyethylene glycol ester functionalities were obtained. The photochemical reaction conversion was found to be approximately 80%. The highest charge density (0.097 meq/g) could be achieved on the glycolic acid ester membrane. The hydrophilicity of the membrane surface is increased by polysulfonamide coating and further increased by photochemical functionalization.

The microfiltration flux and separation performance of these membranes with polystyrene latex (PSL) and carboxylate modified latex (CML) spheres, was examined. The extent of fouling of the membranes was studied by SEM. A lower separation of PSL and a higher pure buffer flux were found for the functionalized membrane compared to the polysulfonamide coated control (DK) membrane. Pure buffer flux was increased after photochemical modification. These results suggest that the increase of hydrophilicity of the photochemically modified membranes was the dominant factor affecting the membrane separation performance. The degree of fouling of the functionalized membranes was significantly decreased which would presumably lead to an improvement of membrane effective life-time.

A remarkable change of polypropylene microfiltration membrane performance was found after the addition of Triton X-100 to the PSL feed solution. This phenomenon was explained in terms of the change of membrane surface properties. Polyethylene glycol ester membranes were introduced to mimic the membrane physically adsorbed Triton X- 100. The results suggested that the Triton X-100 in the testing solution not only temporarily modified the membrane surface properties to be more hydrophillic, but also prevented the PSL particles from aggregating, particularly in the membrane pores.

abstract: Doctor of Philosophy (PhD)


title: Transport and infrared properties of ion irradiated yttrium barium copper oxide thin films

contributor:
Preston, John S.
Physics and Astronomy

subject:
Physics and Astronomy
Astrophysics and Astronomy
Astrophysics and Astronomy

abstract: The discovery of high temperature superconductors prompted the reconsideration of numerous aspects of superconductivity. Among the most fundamental and controversial is the origin of dissipation in a current carrying superconductor. This is also very important from an applied perspective since the onset of dissipation, often described by the critical current density Jc, determines the current carrying capacity of a material. In this thesis, low energy, light ion irradiation has been implemented as a means of controlled sample modification. This type of irradiation has the advantage that it does not alter the stoichiometry of the sample but only results in disorder through the creation of point defects. This thesis explores the influence of ion damage on the normal and superconducting properties of YBa₂Cu₃O₇₋δ thin films. Of particular interest is the contrast between the strong sensitivity of Jc and the more modest sensitivity of the critical temperature, Tc, to ion damage. The evolution of the temperature dependent resistivity was measured systematically as a function of ion damage. The decrease in Tc with ion damage was compared to the predictions of several relevant models. A simple model based on Matthiessen's rule was used to describe the scattering rate and carrier density at low damage levels. At higher damage levels the system undergoes a superconductor-insulator transition which was found to be consistent with the Ioffe-Regel criterion. However, the resistivity in the insulating state is not described by any conventional models for strongly disordered materials. Measurements of the non-linear electric field-current density characteristics were performed for several levels of ion damage over a range of temperatures and compared with several models for dissipation. The data were found to be well described at all temperatures and damage levels by a model involving the quantum nucleation of vortex loops. The variation of the superconducting carrier density, ns, with ion damage was extracted and compared with independent measurements of the same quantity by infrared transmission in identically irradiated YBa₂Cu₃O₇₋δ thin films. This represents the first time a direct connection has been established between Jc and ns in high temperature superconductors.

abstract: Doctor of Philosophy (PhD)


title: Functional polymers derived from 4-methylstyrene

contributor:
H., Harald D.
Chemistry

subject: Chemistry Chemistry

abstract: Novel procedures for the oxidation of 4-methylstyrene homopolymer and copolymers by a single step process have been developed. Poly(4-methylstyrene)s bearing a series of different functional groups (aldehyde, carboxylic acid, acetoxymethyl, nitrooxymethyl, trichloroacetoxymethyl, chloromethyl groups) have been prepared using these oxidation processes. As well, parameters that effect the reaction (molar ratio of oxidants to polymer, cosolvents, temperature, and reaction time) were investigated, and reaction mechanisms for these processes were proposed. A common feature of the oxidations is a reduction in molecular weight of the resulting polymers. Mechanisms of degradation of poly(4-methylstyrene) by ceric (IV) under oxygen or nitrogen were proposed. This backbone cleavage was minimized by forming copolymers of 4-methylstyrene and alkyl methacrylates (methyl methacrylate, n-butyl methacrylate, and dodecyl methacrylate) or of 4-methylstyrene/α-methylstyrene. These copolymers are resistant to oxidative backbone cleavage, due to the steric effect of the α-methyl comonomer. The degree of backbone cleavage depends on the α-methyl comonomer content and sequences in these copolymers. In addition, the thermal properties of functional polymers were studied by thermogravimetry and differential scanning calorimetry.

abstract: Doctor of Philosophy (PhD)


title: Topics in U-line balancing

contributor:
Miltenburg, John G.
Business Administration

subject: Business Administration, Management, and Operations

abstract: The popularity of Just-In-Time (JIT) methods in manufacturing has been rising steadily for the last two decades. U-shaped lines, or U-lines, are an important component of many JIT systems. While production on these lines is similar, in many respects, to that on other configurations, the U shape has significant impact on station assignments, line efficiency and production characteristics of the line. An important decision related to U-line production is the assignment of tasks to stations, the U-line balancing problem. This thesis explores aspects of U-line balancing including the nature of different U-line balancing problems, the production characteristics of U-lines and the efficiency of different solution algorithms. The investigation into U-line balancing begins with the simplest problem, balancing a single U-line constrained only by precedence relationships and the cycle time. The efficiency of U-lines compared to straight lines and the effectiveness of different optimal solution algorithms is evaluated. An effective branch and bound algorithm is identified. It forms a basis for solving more complex problems. One of the differences between U-lines and straight lines relates to the effect of operator travel and station layout on station feasibility. Consideration of operator travel is the second topic explored. Since JIT facilities often include numerous U-lines operating in close proximity, there is an opportunity to increase operator efficiency by constructing stations which contain tasks from more than one U-line. Simultaneous balancing of more than one line is introduced as the two U-line balancing problem and extended to N U-line balancing. If access to U-lines is restricted to the opening of each U-line, the first problem may be solved optimally for typical problems. The complexity of N U-line balancing dictates the use of heuristics solution algorithms. The nature of JIT production frequently requires the mixing of production of several product models on a single line. One of the difficulties with mixed-model production is that different models require different production resources and task processing times vary from one model to the next. During mixed-model production station times will fluctuate, a condition termed model imbalance. Mixed-model production on U-lines is examined and solution algorithms which smooth the degree of model imbalance are offered. The particular advantages of U-lines for mixed-model production are explored. In the final section the problem of U-line balancing is extended to include consideration of stochastic task processing times. A constrained version of this problem may be solved using dynamic programming. For general stochastic U-line balancing problems a heuristic solution is found by employing a simulated annealing algorithm. In this thesis a number of advantages of U-lines over straight lines are illustrated. These advantages provide an incentive for the incorporation of U-lines into manufacturing processes.

abstract: Doctor of Philosophy (PhD)


title: On non-uniform pumping effects in semiconductor lasers

contributor:
Simmons, J.G.
Thompson, D.A.
Engineering Physics

subject:
Engineering Physics
Nuclear Engineering
Nuclear Engineering

abstract: We present a study of non-uniform pumping effects in semiconductor lasers. The first portion of this work is a theoretical undertaking, in which a physical model of a split-electrode, ridge-waveguide, InGaAsP/InP laser is developed. This model is based on the time-dependent solution of the carrier and photon rate equations, and is capable of describing such device features as multiple electrical contacts, illumination of the facets via an external light source, multiple optical cavity modes, and continuous variations in the carrier and photon concentrations. The simulations generated from this model demonstrate: (1) output power vs. bias characteristics that include threshold control, discontinuities, and bistability, (2) wavelength tuning via gain peak shifts and varying refractive index, (3) self-sustained pulsations caused by repetitive Q-switching, (4) external injection effects such as injection locking, all-optical switching, and optical self-pulsation control, and (5) current modulation characteristics. The effects of varying the device bias and geometric parameters on these phenomena are presented. The second part of the thesis consists of an experimental investigation of a series of multi-quantum well InGaAsP/InP split-contact lasers. By varying the bias currents and contact lengths, we have studied their effects on the output power and spectra of these devices. The experimental results we present are in good agreement with the simulations based on our theoretical model.

abstract: Doctor of Philosophy (PhD)


title: THE BAUSCHINGER EFFECT AND APPLICATIONS TO THE MANUFACTURE OF HIGH STRENGTH LINEPIPE

contributor:
Sowerby, R.
Mechanical Engineering

abstract: The macroscopic stress-strain characteristics of many common engineering materials embraces several complex phenomena which are generally attributed to the dependence on loading history. Certain particular aspects of this history related behaviour may be classified under the general heading, the Bauschinger Effect. Investigations into the Bauschinger Effect have produced a variety of continuum plasticity models to explain the phenomenon. The models vary in their degree of complexity but even the more sophisticated ones have not always shown good agreement with experimental observations. Microscopic theories have also been proposed to describe the work hardening behaviour of alloys composed of a hard second phase in a plastically deformable matrix. The work of Brown and Stobbs is an example in which the Bauschinger Effect is treated as an integral part of the work hardening phenomenon in a two phase material. This thesis examines three continuum models in some detail in order to determine the role played by internal stresses on the macroscopic behaviour and the Bauschinger Effect. A modification to an existing model is introduced and shown to improve the description of some experimentally determined cyclic stress-strain data. Furthermore, the microscopic model due to the Brown and Stobbs has been studied quantitatively. The original model was proposed based on detailed observations of the plastic deformation of a simple model system of dispersion hardened single crystals of copper-silica. In this present study, an attempt is made to generalize the model to more complex polycrystalline systems comprised of four spheroidized plain carbon steels which contain different volume fractions of Fe₃C type carbides and three linepipe grade HSLA steels, the microstructures of which are relatively more complex. The experimental inputs to the model were determined from reverse flow experiments performed in a well aligned tension - compression loading fixture. The final aspect of the work of this thesis was focused on the study of an industrial application in which the Bauschinger Effect can play a major role. The D-O-E pipe making process was selected for study in this regard. The general objective of the thesis was to provide a better understanding of the Bauschinger Effect in terms of its causes and practical implications in common structural steels. Certain specific conclusions have been reached in this regard.

abstract: Doctor of Philosophy (PhD)


title: Agniology Revisited or Why We Should Interpret All of Our Knowledge -- Claims in Belief-Contexts

contributor:
Griffin, N. J.
Philosophy

subject: Philosophy Philosophy

abstract: This thesis is an introductory investigation into the logic of scepticism -- at least what I have chosen to call scepticism -- the contention that our everyday presumption that there is such a thing as a purely objective knowledge is a mere pipe dream. Throughout the thesis I defend such a sceptical thesis, making use of classical sceptical counter-hypotheses, but with a special emphasis on the under-lying arguments hidden behind such hypotheses. For this reason the essay, at points, becomes rather technical (logically), and I can only offer my readers my apologies for these complexities. It was my hope in writing this thesis to convince my readers of the unmitigated reasonableness of the brand of "scepticism", which I have purported in this essay. Having completed the writing, I have my doubts as to whether I have succeeded in this task. I feel, however, that the weakness lies not in the argument, but in my failure to present the argument in its most persuasive attire.

abstract: Master of Arts (MA)


title: Thermal neutron capture studies in five isotopes of selenium

contributor:
Kennett, T.J.
Biology

subject: Biology Biology

abstract: The gamma ray spectra associated with thermal neutron capture in targets of ⁷⁶ ⁷⁷ ⁷⁸ ⁸⁰ ⁸²Se have been observed with a high sensitivity pair-spectrometer. Parameters to describe each resolved component are estimated from the measured data. Removal of impurity contributions allows individuals transitions to be attributed to each of the capture reactions. The main application of this information is to reveal details of the structure of the product nuclides. This is realized by the construction of the five radiative decay schemes. Energies and decay modes of quantum states are surmised and new levels are proposed. Optimization of the level energies, and final neutron binding energy, Sn, enhances the precision of previous values. This work produces a three-fold increase in the number of high energy transitions attributed to the larger cross section targets (A=76,77,80), and an order of magnitude enhancement of the transition data for ⁷⁸Se(n,ϒ), as well as the first Identification of transitions in the ⁸²Se(n,ϒ)⁸³Se reaction. In the last case, the value of Sn disproves the long accepted result. The development of Bayesian deconvolution made this extensive analysis feasible. Adapting this technique for Ge(Li) pair-spectra entailed the invention of an automatic continuum removal algorithm and the development of codes for automatic peak analysis. These tools are described in some detail. The art of construction decay schemes from gamma ray data is refined through a new system of procedure to discriminate against the inclusion of false cascades. Several of the measurement techniques described here are pertinent to quantitative studies in other fields.

abstract: Doctor of Philosophy (PhD)


title: Shell structure and classical orbits in mesoscopic systems

contributor:
Bhaduri, Rajat K.
Physics

subject: Physics Physics

abstract: The theme of this thesis is to understand global shell structure of a finite many-fermion system in connection with short periodic orbits of the corresponding classical system. It is the overall shell structure, or partly resolved quantum fluctuations in the density of states, that is often enough for describing various properties of a system of interacting particles. Through semiclassical periodic orbit theory, one can visualize quantum-mechanical phenomena in terms of simple classical orbits. It is particularly interesting to study this quantum-classical connection in the mesoscopic systems of simple metal clusters and quantum dots, as their size as well as the number of particles can be much larger than in such systems as atoms and nuclei. We first illustrate a direct connection between quantum shells and classical periodic orbits by means of a mathematical model of a cranked two-dimensional harmonic oscillator. The quantum spectrum exhibits intriguing features, forming the Farey fan pattern. Furthermore, there is an analogy between this cranked model and the system of charged particles in a uniform magnetic field. We then go on to examine the electronic shell structure of simple metal clusters and quantum dots under a homogeneous magnetic field, taking simple mean-field models for these systems. The so-called supershell structure, a long-range, beating modulation of the electronic shell structure of simple metal clusters, is a fascinating example which can be explained semiclassically in terms of short periodic orbits of high degeneracy. We study the effect of an external magnetic field on this supershell structure, assuming a spherical infinite well as a simple yet realistic mean-field potential for the valence electrons. It is found that there is little perceptible change in the supershells for experimentally feasible field strengths, and if yet stronger fields are assumed, the supershells get destroyed and new beat patterns appear. For semiclassical understanding of these phenomena, we apply a recently developed trace formula for broken symmetry to this system. The system of quantum dots is more interesting than metal clusters in that its size can be much larger and the effect of magnetic fields on the electronic shell structure is observable for readily available field strengths. We examine the magnetization and magnetic susceptibility of a circular quantum dot with the two limiting cases of mean-field potential for a small and large number of confined electrons. The shell structure rejected in these magnetic properties are compared in the two cases and are interpreted through short classical orbits. In particular, the Aharonov-Bohm oscillations that appear in the strong-field limit, superimposed on the de Haas-van Alphen oscillations in the magnetization, are explained in terms of the shortest orbits that go along the edge of the system.

abstract: Doctor of Philosophy (PhD)


title: A STUDY OF THE INTERFACIAL REACTION KINETICS IN THE IRON - CALCIUM-FLUORIDE SYSTEM AT 1450 DEGREES C

contributor:
Lu, W-K.
Metallurgy

subject: Metallurgy Metallurgy

abstract: An understanding of the chemical reaction kinetics at a slag/metal interface requires knowledge of both transport and interfacial properties. However, fundamental interfacial reaction rate data are largely unavailable. Consequently, the ion exchange current density and interfacial capacitance have been measured with the double pulse galvanostatic method for the anodic dissolution of an iron electrode in liquid CaF(,2) and CaF(,2)-CaO slags. Both the exchange current and capacitance are strongly increasing functions of concentration. The measured exchange current densities are large (ranging from 4.5 to 400 amperes/cm('2)), so that a non-linear extrapolation of the experimental data is necessary. The kinetics of oxygen transfer at the Fe/CaF(,2) interface was studied in independent experiments. The reaction was driven by an FeO activity gradient. The kinetic information obtained in this manner compares favourably with that derived from the electrochemical technique. With suitable information on the relative magnitudes of transport and reaction rates, it is possible to predict the kinetic regime for the entire system (i.e. transport, reaction, or mixed control). The experimental data indicate that mixed control of the reaction kinetics will prevail at the Fe/CaF(,2) interface in the absence of forced stirring. If the kinetic parameters in more complex metallurgical systems are similar to those measured at the Fe/CaF(,2) interface, the influence of interfacial charge transfer reactions may be greater than is normally supposed.

abstract: Doctor of Philosophy (PhD)


title: The life and thought of Michael Sattler, Anabaptist

contributor:
Vallee, Gerard
Religion

subject: Religion Religion

abstract: The aim of this study is to shed light on the thought of Michael Sattler, formerly a Benedictine monk, later an Anabaptist leader and author of the influential Schleitheim Articles. The method followed has been first to seek out potential sources of influence on Sattler by re-examining his life, following which the relevant literature has been analyzed. Concerning his pre-Anabaptist life it has been shown that at St.Peters of the Black Forest Michael Sattler lived in a monastery under-going reform. This observant monastic background is central to understanding Sattler's subsequent thought as an Anabaptist. This study concludes further that the rebellious Black Forest peasants played a central role in providing Sattler his point of contact with the evangelical, revolutionary and Anabaptist movements. Following his departure from the monastery, Sattler resided in the Zurich Unterland, living in the house of a radical Anabaptist weaver. He was rebaptized in the late summer of 1526. Michael Sattler thus belongs to the second generation of Anabaptist leaders which emerged following the failure of both the peasants' revolt and early Anabaptist efforts at territorial church reform. An analysis of Sattler's thought shows that of the monastic, evangelical and peasant milieux to which he had been exposed the primary imprint on his thought stems from his monastic past. Although he follows a Protestant lead in holding to sola scriptura, a corresponding doctrine of sola fide is absent. Sattler's interpretation of scripture, his Christology, his soteriology and his ecclesiology all recall monastic, rather than Protestant, theology. Michael Sattler accepted the doctrines basic to the early Swiss Anabaptists -- adult baptism, the ban, and a commemorative Lord's Supper -- but he introduced significant monastic elements into the Anabaptist tradition through the Schleitheim Articles. In particular he contributed a monastic emphasis on following Christ, as well as a doctrine of the church as the separated, ascetic community of saints.

abstract: Doctor of Philosophy (PhD)


title: Multiphoton absorption spectroscopy of iodine

contributor:
King, G.W.
Chemistry

subject: Chemistry Chemistry

abstract: Two independently tunable excimer laser pumped dye lasers have been used to examine the high resolution (Δυ~0.1 cm⁻¹) three-photon absorption processes for the isotropic molecules, ¹²⁷I₂ and ¹²⁹I₂. Multiphoton spectra have been obtained by monitoring the undispersed fluorescence from highly excited states, either through the use of a single tunable dye laser (3P1C) or with the use of two dye lasers in tandem (3P2C). Four separate electronic states accessed by a 3-photon (3P) process have been observed in the 47000-60000 cm⁻¹ energy region. A detailed rotational analysis has been possible for the four states, three of which are shown to be of ion-pair character and oᵤ⁺ symmetry. The fourth state is shown to be of extra-valence (Rydberg) character and of oᵤ⁺ symmetry. This later state is reported for the first time and it is one of the few Rydberg states to be analysed rotationally. The results of several previous studies are incorporated into the analyses, and reinvestigation of unanalysed MPI spectra reported by other workers is discussed and analysed in this study.

abstract: Doctor of Philosophy (PhD)


title: Azomethine ylides from Delta(1)-1,2,4-triazolines and allylaminomaleates from reactions of allyamines with dimethyl acetylenedicarboxylate

subject: Chemistry Chemistry

abstract: The major portion of this thesis deals with the chemistry of 5-t-butyl-3,3-dimethyl-5-methylene-∆¹-1,2,4-triazoline (94) and its derivatives. Triazoline 94, formally also an enamine and an azo compound was treated with several substrates in attempts to synthesize new ∆¹-1,2,4-triazolines suitable for the generation of azomethine ylides. When 94 was treated with heterocumulenes or simple Michael acceptors such as acrylonitrile, the products included highly substituted aziridines (e.g., 109), simple Michael addition products which contain the skeleton of 94, and in one instance, an azabicycloheptene: The reaction of 94 with more-substituted Michael acceptors, methacrylonitrile and methyl methacrylate, yielded 2-t-butyl-iminopyrrolidine derivatives. When 94 was treated with heterocumulenes or simple Michael acceptors such as acrylonitrile, the products included highly substituted aziridines (e.g., 109), simple Michael addition products which contain the skeleton of 94, and in one instance, an azabicycloheptene. The reaction of 94 with more substituted Michael acceptors, methacrylonitrile and methyl methacrylate, yielded 2-t-butyl-iminopyrrolidine derivatives. Spirotriazolines (e.g., 129a) were isolated from the reaction of 94 with benzonitrile oxide and diphenylnitrilimine. The thermal decomposition of these spiro species was found to follow the first order rate law. Treating 94 with phenyl azide and p-nitrophenyl azide provided spiro triazolines whose thermal decomposition involved the loss of two moles of molecular nitrogen. An analog of 94, bearing a fumarato substituent on the exocyclic double bond was found to rearrange to a highly-substituted pyrrole when heated in MeOH. Another analog of 94, this species bearing an anilido substitutent on the exocyclic double bond, was found to lose nitrogen with first order kinetics when heated in MeOH or C₆H₆. In a separate study, allyldimethylaminomaleates (e.g., 177a) resulted from the reactions of allyldimethyl amines with dimethyl acetylenedicarboxylate. The maleates are believed to arise from initial zwitterion formation followed by intramolecular allyl transfer via a evelie 6-membered transition state.

abstract: Doctor of Philosophy (PhD)


title: Power System Stability Including Dynamic Equivalents and Reduced Order Models

contributor:
Alden, R.T.H.
Electrical Engineering

subject:
Electrical and Electronics
Electrical and Electronics

abstract:
Dynamic stability of multimachine and single machine-infinite bus systems is considered. System models are described, which include detailed generator, turbine, governor and exciter components, in addition to dynamic representation of mechanical loads and electrical networks. The overall modeling concepts are applied to a number of practical applications to demonstrate their behavior in power systems dynamic studies.

A variety of linear dynamic equivalents are employed to reduce the complexity of stability studies for multi machine power systems. Undrill's technique for constructing linear dynamic equivalents is extended and improved in this thesis.

Various reduction techniques are applied to reduce the order of the system. Mainly they are aggregation and singular perturbations techniques. The interactions between the reduction techniques and dynamic stability are explained.

Insights are presented into the interpretation of eigenvalues and eigenvalue sensitivities as they reflect the various aspects of power system stability predictions in high order models, they are extended to be applied in reduced order models.

The concepts considered are employed in the analysis of several examples utilizing actual power system data.

abstract: Master of Engineering (ME)


title: TEMPERATURE PROFILES IN SUBCOOLED NUCLEATE BOILING

contributor:
Judd, R. L.
Mechanical Engineering

subject:
Engineering
Mechanical Engineering
Engineering

abstract:
An experimental study of temperature profiles in the near vicinity of a horizontal copper surface on which water was boiled is reported in this thesis. A series of three tests is reported for heat fluxes of 20,000, 50,000 and 100,000 BTU/HRFT2 respectively. Four levels of subcooling were achieved in each series in the range of 0F < 0sub < 105F. Using the superheat-layer thickness as defined by Han and Griffith, results are reported indicating an increase in superheat-layer thickness for an increase in the degree of subcooling at a constant heat flux and a reverse effect for an increase in heat flux for a constant degree of subcooling.

In addition, five tests are reported in which incipience of boiling was achieved. Using this data, Hsu's mathematical model for predicting bubble nucleation is tested. In general, good agreement is found between the Hsu model and the experimental data.

abstract: Master of Engineering (ME)


title: Interactive computer graphical approaches to some maximin and minimax location problems

contributor:
Wesolowsky, G. O.
Management Science/Systems

subject: management science/systems

subject: Management Sciences and Quantitative Methods

abstract: This study describes algorithms for the solution of several single facility location problems with maximin or minimax objective functions. Interactive computer graphical algorithms are presented for maximizing the minimum rectilinear travel distance and for minimizing the maximum rectilinear travel distance to a number of point demands when there exist several right-angled polygonal barriers to travel. For the special case of unweighted rectilinear distances with barriers, a purely numerical algorithm for the maximin location problem is described. An interactive computer graphical algorithm for maximizing the minimum Euclidean, rectilinear, or general l$\sb{\rm p}$ distance to a number of polygonal areas is described. A modified version of this algorithm for location problems with the objective of minimizing the maximum cost when the costs are non-linear monotonically decreasing functions of distance is presented. Extension of this algorithm to problems involving the minimization of the maximum cost when the costs are functions of both distance and direction is discussed using asymmetric distances.

abstract: Doctor of Philosophy (PhD)


title: PETROGRAPHY, GEOCHEMISTRY AND GEOCHRONOLOGY OF THE COE HILL GRANITE, HASTINGS COUNTY, ONTARIO

contributor:
Shaw, D.M.
Geology

subject:
Earth Sciences
Geology
Physical Sciences and Mathematics
Earth Sciences

abstract:
A detailed petrographic, geochemical and strontium isotope study of the rocks representing the variations observed across the Coe Hill granite, Grenville Province, southeastern Ontario provides the basis for the determination of the age and possible origin of this pluton. This study also provides insight into the relationships between similar granitoid plutons in the immediate vicinity.

The Coe Hill granite is a medium to coarse grained hypidiomorphic to allotriomorphic, leucocratic quartz monzonite with subordiante isolated inclusions of dioritic and gabbroic gneiss. Variations upon this otherwise homogeneous granitoid occur in discordant aplite dykes, assimilating mafic xenoliths and along brecciated contact boundaries.

Generally the rocks of this pluton are more basic than the average for similar granitoids in the area (12.4% vs. 6.0% mafics) as observed in both thin section and major element oxide diagrams. Besides this trend major element diagrams have uniform distributions. A Rb-Sr isochron was determined for the rocks of the pluton proper which gave an age representative of the emplacement of these rocks (t = 1063 21 m.a.; R1 = 0.7040 +- 5). Trace element Rb shows a value similar to the norm for granitoids yet is enriched in comparison to values acquired from similar granitoids in the area (144 ppm vs. 63 ppm).

Through a synthesis of the available data, and that which was acquired from this study on the Coe Hill granite, a comparison with the available data on the Loon Lake quartz monzonite can be made. This comparison illustrates a great deal of strikingly similar trends which have been taken to represent a lower crustal, or upper mantle origin, cogenetic relationship between these two granitoids.


title: Identity and its maintenance in later life a social network approach

contributor:
Matthews, Ralph
Sociology

subject: Sociology

abstract: This study examines what growing old means for the older women's sense of self-identity. Some gerontologists argue that old age constitutes a period of role loss with detrimental impact on identity. A sizable body of data do not support this assumption. The underlying assumption of this study is that identity emerges and is sustained through social interaction. Thus the research focuses on (1) the meaning of 'being old' as defined by older women and (2) the extent to which a positive identity can be retained through social network involvement with family, friends and community leisure activities. Instead of focusing on what is lost, the emphasis was on determining what role relationships are retained and established in old age, and the extent to which these serve to maintain a positive self image. The research is based on interviews with 142 women over age 65 living in town of Bridgewater, Nova Scotia. The principle component of this sample comprised 101 women living in their own homes or apartments (i.e. community-dwelling). Most of the analysis is based on this sample. However, where comparative analysis is useful, these data are supplemented with information from interviews with 31 residents of senior citizen apartment completes and 10 residents of a nursing home. The findings indicate that the elderly women studied here generally do not view themselves as 'elderly' or 'old'. Age identity is found to be largely situational and more relevant to some interactions than others. The majority have managed to retain a positive identity which is deeply embedded within their informal role involvements and social network ties. As a result, the loss of more formal role relationships had only limited impact on identity. The findings also indicate that a relatively stable small community appears to offer advantages for identity management in old age.

abstract: Doctor of Philosophy (PhD)


title: Energy analysis of brittle fracture and its application to zirconium-oxide ceramics

contributor:
Nicholson, P.S.
Materials Science

subject:
Materials Science and Engineering
Materials Science and Engineering

abstract: The most useful properties of ceramics (high temperature strength, chemical inertness and hardness at low density) are accompanied by brittleness. This is still the main factor limiting widespread application of ceramic materials. In the present thesis an energy approach to fracture of ceramics was undertaken and refined to account for a nonelastic behaviour of these materials. A chevron-notched (CN) four-point bend specimen was recognized as effective experimental arrangement for room and elevated temperature tests. Consequently, a number of theoretical studies of the specimen's performance were undertaken. Modelling of the variation of the strain energy release rate with the crack extension revealed that the subcritical crack growth in a CN specimen causes dependence of the measured fracture parameters on the experimental procedure (stressing rate, stiffness of the testing system, crack length). It appears that, as complete fracture is approached (i.e. 100% of the specimen's cross-section), the measured work-of-fracture approaches that required for crack initiation. An electrical potential drop technique for crack length measurement in the CN specimen was developed for elevated temperatures fracture studies in the ionically conducting zirconium oxide ceramics. The resistance-to-fracture versus crack extension was determined for a range of temperatures (25 to 1300℃) for stabilized zirconias and their HfO₂ solid solutions and with second phase p-Al₂O₃ particles dispersed in them. The room temperature results agreed with the literature data and model predictions. Above 1000℃ an energy input of ⁻1 J/m² is required to drive the crack through zirconium oxide ceramics. Viscoelastic effects and crack interaction with p-Al₂O₃ particles result in a total fracture energy dissipation two orders of magnitude higher.

abstract: Doctor of Philosophy (PhD)


title: Factors influencing the thrombogenicity of injured rabbit aortae

contributor:
Kinlough-Rathbone, R. L.
Medical Sciences

subject:
Medical Sciences
Medical Sciences

abstract:
The interaction of platelets with damaged vessel walls plays a role in the development of atherosclerosis and its thromboembolic complications. The platelets that adhere to injured vessels release a growth factor that promotes the migration of medial smooth muscle cells through the internal elastic lamina into the subendothelial connective tissue where they proliferate and form a neointima. If a vessel is exposed to repeated or continuous injury the process continues and ultimately a frank atherosclerotic plaque develops. A plaque contains not only smooth muscle cells, but large quantities of intracellular and extracellular lipid and cholesterol. These plaques can lead to distrubed flow, and the development of thrombi, particularly in regions where abnormal flow patterns caused further endothelial cell injury or desquamation. The purpose of the work reported in this thesis was to examine the factors influencing the response of vessels to injury, since our understanding of these should contribute to our knowledge concerning the processes involved in atherosclerosis and its complications. Previous studies have examined the responsiveness of normal vessels of young animals to a single injury and may therefore have little relevance to injury of previously damaged or diseased vessels. The present experiments were therefore designed to produce conditions likely to be found in older vessels that have been exposed to previous injury. In these experiments rabbit aortae were de-endothelialized with a balloon catheter and a smooth muscle cell-rich neointima was allowed to develop over a 7 day period. The response of this surface to a second injury with a balloon catheter was examined and compared with the response of normal vessels to a single injury. The initial response to a second injury was very different from the response to a single injury. Whereas a monolayer of platelets accumulates after de-endothelialization, following injury of a smooth muscle cell-rich neointima, large platelet-fibrin thrombi form on the injured surface. The platelet-fibrin thrombi are largely oriented in the direction of blood flow. Despite the fact that coagulation is activated (the thrombin that is generated leads to fibrin formation) the number of platelets (measured using platelets prelabelled with ⁵¹Chromium) that accumulates on the injured aortic surface is similar to the number that accumulates on a de-endothelialized aorta, and the surface that is initially very reactive to circulating platelets rapidly loses its ability to attract fresh platelets. The reasons for the non-reactivity of normal endothelium and loss of reactivity of both de-endothelialized vessels and vessels subjected to a second injury were explored. Although it has been speculated that the PGI₂ produced by normal vessels or injured vessels could account for the lack of interaction of platelets with these surfaces, this did not seem to be so, since inhibition of PGI₂ production by treatment of vessels in vitro or in vivo with aspirin did not lead to platelet accumulation on undamaged vessels or enhance platelet accumulation on injured vessels. Similarily, products of the lipoxygenase pathway that have been implicated as responsible for the non-thrombogenicity of vessels did not appear to be responsible for the lack of accumulation of platelets on these surfaces, since inhibitors of lipoxygenase such as ETYA (15-hydroxy-5, 8, 11, 13-eicososatetraenoic acid) or NDGA(nordihydroguiaretic acid) did not influence the number of platelets that accumulated on the vessels under the conditions tested. To determine if factors other than platelets could account for the lack of vessel wall reactivity, platelet accumulation in vivo on de-endothelialized vessels or on vessels with an injured neointima was prevented by treating animals with injections of dipyridamole or with constant infusions of PGI₂. It was observed that 6 to 8 hours of these treatments are required for the vessels to become non-reactive; shorter durations of treatment do not allow the surface to develop its non-thrombogenic properties. Thus, the loss of reactivity of injured vessels do not require platelet adherence to the injured surface. In addition, it can be inferred that plasma factors or material from circulating red blood cells does not contribute to this effect. It may be that the loss of reactivity that develops over a 6 to 8 hour period may be attributable to a factor(s) elaborated by injured vessels and this is an avenue worthy of exploration.

Several general conclusions can be reached based on the observations in this study. First, since injured vessels rapidly lose their reactivity to circulating platelets, repeated or continuous vessel injury is probably required for the development of severe arterial disease. Second, since activation of coagulation plays major role in the response to injury of previously injured vessels, treatment with anticoagulants could be useful therapy in some forms of arterial thrombosis. Finally, since injured vessels lose their reactivity to platelets even when the initial interaction of platelets with the injury site is prevented, it may prove useful to administer drugs that inhibit platelet adherence to damaged vessels for short periods only, for example, after coronary bypass surgery or transluminal angioplasty. This would allow "passivation" of the surface, prevent the effects on smooth muscle cell proliferation of growth factors released from adherent platelets, and reduce the vessel wall thickening that could compromise flow to the tissues.

abstract: Doctor of Philosophy (PhD)


title: Intrinsic versus extrinsic factors associated with embryonic nerve-muscle specificity

contributor:
Cosmos, Ethel
Medical Sciences, Neurosciences

subject: Neurosciences Neurosciences

abstract: Previous analyses showed that following heterotopic transplantation of a thoracic neural tube segment into the region of the extirpated brachial neural tube in experimental (Thor-Br) chick embryos at embryonic day -2 (day -2E) the wings of hatched Thor-Br chicks are immotile. It was not known, however, if functional nerve-muscle interaction occurs during embryogenesis of Thor-Br embryos, although structural nerve-muscle connections do form in wing muscles during initial development of this experimental model. From day 8.5-9E onward, however, thoracic nerve-brachial muscle unions progressively uncouple in individual wing muscles. The present study explored the nature of initial nerve-muscle contacts and employed a well documented functional parameter, wing motility, to monitor daily the development of functional nerve-muscle interactions in wings of individual Thor-Br embryos. Control embryos were either unoperated (UC) or received a homotopic brachial neural tube transplant (Br-Br). The results demonstrated that Thor-Br embryos exhibited normal frequencies of wing movement up to day -8E; but the frequency of wing movement became greatly reduced from that of controls following this initial developmental period. The loss of wing motility in Thor-Br embryos coincided temporally with the withdrawal of intramuscular axons from individual wing muscles reported previously. Thus, foreign thoracic nerves did establish initial functional contacts with wing muscles, however, these connections were subsequently deemed inappropriate and nerve-muscle unions progressively uncoupled. To investigate factors responsible for the nerve-muscle uncoupling phenomenon observed in experimental (Thor-Br) embryos the development of heterotopically transplanted thoracic neural tubes was compared to that of neural tubes in control (Br-Br and UC) embryos. Parameters analysed include the pattern of peripheral nerve outgrowth, neural tube histogenesis, the source of motor innervation to individual wing muscles and the pattern of motoneuron death, growth and differentiation. The results showed that while the pattern of nerve outgrowth was controlled by local environmental signals, developmental events within the neural tube was governed autonomously, independent of the periphery. Thus, heterotopically transplanted thoracic neural tubes developed according to their site of origin. In addition to the heterotopic neural tube (Thor-Br) transplantation experiments a second series of surgically manipulated chick embryos (Thor-Br/som) was employed to determine if nerve-muscle incompatibility is limited to a thoracic nerve-brachial muscle combination. Experimental (Thor-Br/som) embryos were produced by transplanting thoracic somitic mesoderm into the site of extirpated brachial somites at day -2E. Daily wing motility analyses were performed to determine the extent of functional nerve-muscle interaction between in situ brachial nerves and wing muscles derived from heterotopically transplanted thoracic somitic mesoderm. The results demonstrated that functional nerve-muscle interaction did occur in wings of Thor-Br/som embryos and, in contrast to experimental (Thor-Br) embryos, wing motility was maintained in Thor-Br/som embryos throughout the developmental period analysed (day -6E through day -16E). Nerve-muscle uncoupling, therefore, dd not occur in heterotopic somitic mesoderm transplantation experiments. It was concluded that eventual nerve-muscle incompatibility observed following heterotopic neural tube (Thor-Br) transplantation is related to the rigidity of developmental processes within the spinal cord. Whereas heterotopically transplanted thoracic somitic mesoderm exhibited a high degree of plasticity and conformed to peripheral signals derived from the brachial environment, transplated thoracic neural tubes were unable to respond to environmental signals were eventually deemed inappropriate.

abstract: Doctor of Philosophy (PhD)


title: KINETICS OF GASEOUS REACTIONS OF THE HYDROXYL RADICAL WITH SELECTED CYCLOALKENES AND AROMATIC COMPOUNDS

contributor:
Yarwood, A.J.
Chemistry

subject: Chemistry Chemistry

abstract: The kinetics of the OH radical reactions with selected cycloalkenes and aromatic compounds were studied in the gas phase with the flash photolysis-resonance fluorescence technique. Five OH-cycloalkene reactions were studied at temperatures between 295 and 428 K. The significance of the allylic hydrogen abstraction process relative to the addition process in these reactions is discussed. On the basis of the room-temperature rate constants, the significance of the OH radical reactions with cycloalkenes in the troposphere is considered. Arrhenius parameters were calculated for each reaction. The reactions all have negative apparent activation energies of $\sim4 - 5$ kJ mol$\sp{-1}$; values similar to those of OH-alkene reactions. The factors which might determine the relative reactivity of various OH-alkene and OH-cyclo-alkene reactions are examined. The kinetics of the OH-benzene reaction were studied at temperatures between 295 and 425 K. The validity of the previously proposed mechanism and the reasons for the discrepancies among the studies reported in the literature are examined by comparing the observed kinetics with the predictions of computer simulation of the mechanism. The temperature dependence of the OH-chlorobenzene reaction was studied in the same temperature range, and the kinetics were compared with those of the OH-benzene reaction. The OH radical reactions were also studied at room temperature with six selected halogenated benzenes and biphenyl. The factors which might determine the relative reactivity of these reactions and other previously reported OH-aromatic reactions are discussed. The rate constants of various OH-chlorinated benzene reactions at room temperature were used as a model to estimate the relative reactivity of the OH-polychlorinated biphenyl reactions, and to discuss the significance of the reactions in determining the atmospheric lifetimes of polychlorinated biphenyls.

abstract: Doctor of Philosophy (PhD)


title: Studies on Rous sarcoma virus reverse transcriptase biogenesis

contributor:
Ghosh, Hara P.
Biochemistry

subject: Biochemistry Biochemistry

abstract: The purpose of this thesis was to investigate the biosynthesis and function of reverse transcriptase in relation to the assembly and maturation of RNA tumor viruses. The assembly and maturation of RNA tumor viruses were examined by biochemical characterization of a conditional lethal mutant of Rous sarcoma virus (RSV). The functional aspects of reverse transcriptase was investigated by recombinant DNA methods. A temperature-sensitive coordinate mutant tsLA83 of Prague B (PR-B) strain of RSV at the nonpermissive temperature (41℃) produced noninfectious virus particles (NI-LA83) which contained only 3% of the reverse transcriptase activity present in infectious virions. Analyses of [³⁵S] methionine labeled NI-LA83 showed the presence of all of the viral proteins except revere transcriptase. Pulse-chase analyses of the virus specified proteins in cells infected with LA83 or PR-B showed that the gag and glycoprotein precursors, Pr76ᵍᵃᵍ and gPr92ᵉⁿᵛ, respectively, were processed at both 35℃ and 41℃. The reverse transcriptase precursor, Pr180ᵍᵃᵍ⁻ᵖᵒˡ, however, was not processed in La83-infected cells at 41℃. In contrast, cells infected with LA83 or PR-B at 35℃ as well as with PR-B at 41℃ showed normal cleavage of Pr180ᵍᵃᵍ⁻ᵖᵒˡ. A shiftdown of LA83-infected cells at 41℃ to the permissive temperature, 35℃, resulted in the normal processing of Pr180ᵍᵃᵍ⁻ᵖᵒˡ and production of infectious virus containing reverse transcriptase. Electron microscopic analysis showed that at 41℃ cells infected with LA83 showed a large number of budding structures but fewer released particles. A shiftdown from 41 to 35℃ resulted in an increase of virus particles with a concomitant decrease in budding structures suggesting that the processing of reverse transcriptase precursor is related to virion assembly. The mechanism of synthesis of reverse transcriptase was investigated. Immunoprecipitation experiments have revealed possible intermediates in Pr180ᵍᵃᵍ⁻ᵖᵒˡ processing. These are 130,000- and 150,000-dialton intracellular proteins (Pr130ᵍᵃᵍ⁻ᵖᵒˡ and Pr150ᵍᵃᵍ⁻ᵖᵒˡ) that contain antigenic determinants of reverse transcriptase and gag proteins. Pr130ᵍᵃᵍ⁻ᵖᵒˡ contains antigenic determinants of reverse-transcriptase and p15, Pr150ᵍᵃᵍ⁻ᵖᵒˡ contains all the gag-proteins, but not the complete sequence of reverse transcriptase. Immuno-complexes of Pr180ᵍᵃᵍ⁻ᵖᵒˡ molecules with anti-reverse transcriptase antiserum were tested for in-vitro cleavage in the presence of detergent-disrupted virus (a source of p15, the viral protease). The results identified two possible cleavage intermediates (Pr130 and Pr70). A precursor-product relationship has been demonstrated between Pr180ᵍᵃᵍ⁻ᵖᵒˡ and Pr130ᵍᵃᵍ⁻ᵖᵒˡ, although a direct precursor product relationship could not be demonstrated between Pr180ᵍᵃᵍ⁻ᵖᵒˡ and Pr150ᵍᵃᵍ⁻ᵖᵒˡ. A possible biosynthetic scheme of reverse transcriptase was proposed. In an attempt to establish the structural and functional relationships of the reverse transcriptase molecule, site directed mutagenesis on molecularly cloned RSV proviral DNA was undertaken: Expression of the reverse transcriptase gene in both bacteria and avian cell cultures was studied. E. coli harboring the recombinant plasmids containing proviral DNAs from different strains of RSV synthesized a protein of 65,000 molecular weight (p65) which is immunoprecipitated with anti-reverse transcriptase antiserum. The RNA dependent-DNA polymerase activities from E.coli containing the recombinant plasmids were about 30-fold higher than the background activity present in E.coli containing pBR322. The RNA dependent-DNA polymerase activity was specifically neutralized by the antibody against the reverse transcriptase. A possible translational initiation site was suggested to be an internal methionine residue, which is located at residue number 295 or 297 from the amino-terminus of the mature reverse transcriptase molecule. The amino-terminal one-third of the reverse-transcriptase molecule thus appears to be dispensable for the polymerase activity. The presence of a promoter-like sequence in the reverse transcriptase gene which is involved in the transcription of the polymerase gene for synthesis of reverse transcriptase activity in E.coli has also been suggested. Biological activity of the site directed mutagenized viral DNAs were tested by transfection into chick embryofibroblast cells. Deletion near the 5-end region of the pol gene resulted in inefficient production of virus due to possible functional defect in the truncated reverse transcriptase molecules of inefficient processing of the precursor molecules. However, the cells were transformed. Deletion near the 3-end region of the pol gene resulted in inefficient production of virus and the cells were not transformed. These results suggest that the pp32 DNA binding protein, which is encoded from the 3-end region of the pol gene, or the carboxy terminal moiety of the β subunit, or both, are required in the life cycle of avian retroviruses.

abstract: Doctor of Philosophy (PhD)


title: Fixed points of nonexpansive type multivalued maps

contributor:
Husain, Taqdir
Mathematics

subject: Mathematics Mathematics

abstract: Let (X,d) be a metric space. Husain and Tarafdar call a map J:X→2ˣ (nonempty subsets of X) nonexpansive (here it is called (H∙T)-nonexpansive if for all x ∊X, uᵪ ∊ J(x) there exists vᵧ ∊J(y) for all y∊X such that d(uᵪ,vᵧ) ≤ d(x,y). Clearly this notion generalizes the usual concept of nonexpansive maps and coincides with it for single-valued maps. We study fixed points for such mappings. Further, if in the above inequality we have d(uᵪ,vᵧ) ≤ hd(x,y) for some fixed h, 0≤h<1,. then we generalize the notion of contraction for single valued maps. We proved a fixed point theorem which contains the Banach fixed point theorem as a special case. We introduce and study two more classes of set-valued nonexpansive mappings: s-nonexpansive mappings and f-(H∙T)-nonexpansive mappings. In general, these two types of maps are not related. But both of them contain the class of all single-values nonexpansive maps. However, the class of all f-(H∙T)-nonexpansive mappings contain the class of all (H∙T)-nonexpansive mappings. It is shown that not every (H∙T)-nonexpansive mapping on a nonempty closed convex and bounded subset of a Banach space has a fixed point. Husain and Tarafdar proved that if M is a compact interval of the real line then each (H∙T)-nonexpansive closed convex valued map J:M→2ᴹ has a fixed point. In this thesis, we extend this result which contains some well-known results due to Browder and Karlovitz. Moreover, it includes, as a special case, the result: every single-valued nonexpansive mapping on a nonempty closed convex bounded subset of a reflexive Banach space satisfying Opial's condition has a fixed point. This late result can also be derived from a result due to Kirk, in view of the fact that the Opial's condition implies normal structure. We also prove a fixed point theorem for multivalued s-nonexpansive mapping from which it is derived that every closed convex-values s-nonexpansive mapping on a nonemty closed convex-values s-nonexpansive mapping on a nonempty closed convex bounded subset of a Hilbert space has a fixed point. In addition, we have a fixed point theorem for set-valued (H∙T)-contractive type mappings from which a result due to Kannan can be derived as a special case. Finally, a common fixed point theorem for such mappings is proved.

abstract: Doctor of Philosophy (PhD)


title: Solubilization, purification and pharmacological characterization of bovine striatal dopamine D-2 receptor

contributor:
Mishra, Ram K.
Medical Sciences

subject:
Medical Sciences
Medical Sciences

abstract: With the advent of radioligand binding assays, central nervous system dopamine receptors have been well characterized in their membrane bound state. These receptors have been grouped into D-1 and D-2 subclasses on the basis of their relationship to the enzyme adenylate cyclase and affinities for dopamine agonists and antagonists. The dopamine D-2 receptor is considered relevant to the behavioral and pharmacological effects of neuroleptic drugs. The studies presented in this dissertation describe a successful method of solubilization of bovine striatal membrane bound dopamine D-2 receptor. The solubilized receptor exhibited typical pharmacological characteristics to that of membrane bound dopamine D-2 receptor. The rank order potency of agonists and antagonists to displace [³H]spiroperidol binding was the same as those observed with the membrane bound receptor. Analysis of the [³H]spiroperidol/agonist competition curves and the [³H]NPA binding revealed the retention of high and low affinity states of dopamine D-2 receptor in the solubilized preparation. This study demonstrated for the first time, a successful affinity chromatography method for the purification of dopamine D-2 receptor. One cycle affinity purification resulted in a 2000-fold enrichment of dopamine D-2 receptor activity with a recovery of 12% from the membrane-bound state and a specific activity of 169,600 fmol/mg protein (assayed with [³H]spiroperidol). The order of potency of D-2 agonists (N-propylnorapomorphine > N0434 > apomorphine > dopamine) and antagonists (spiroperidol > (+)-butaclamol > domperidone) with a purified preparation was found to be similar to that of the membrane bond or solubilized dopamine D-2 receptor. The adsorption of receptor to the affinity matrix was biospecific as pre-incubation of the solubilized preparation with D-2 receptor agonists or antagonists blocked retention of receptor activity. Elution of receptor was also biospecific as dopaminergic drugs were effective in eluting the bound receptor. Affinity purified preparations should be useful in producing monoclonal antibody to dopamine D-2 receptor and also prove to be important in understanding the molecular events from receptor drug binding to final response.

abstract: Doctor of Philosophy (PhD)


title: An Optimization-Based Parallel Particle Filter for Multitarget Tracking

contributor:
Kirubarajan, T.
Electrical and Computer Engineering

subject:
Electrical and Computer Engineering
Engineering
Electrical and Computer Engineering

abstract: Particle filters are being used in a number of state estimation applications because of their capability to effectively solve nonlinear andnon-Gaussian problems. However, they have high computational requirements and this becomes even more so in the case of multitarget tracking, where data association is the bottleneck. In order to perform data association and estimation jointly, typically an augmented state vector, whose dimensions depend on the number of targets, is used in particle filters. As the number of targets increases, the corresponding computational load in creases exponentially. In this case, parallelization is a possibility for achieving real-time feasibility in large-scale multitarget tracking applications. In this paper, we present an optimization-based scheduling algorithm that minimizes the total computation time for the bus-connected heterogeneous primary-secondary architecture. This scheduler is capable of selecting the optimal number of processors from a large pool of secondary processors and mapping the particles among the selected ones. A new distributed resampling algorithm suitable for parallel computing is also proposed. Furthermore, a less communication intensive parallel implementation of the particle filter without sacrificing tracking accuracy using an efficient load balancing technique, in which optimal particle migration among secondary processors is ensured, is presented. Simulation results demonstrate the tracking effectiveness of the new parallel particle filter and the speedup achieved using parallelization.

abstract: Master of Applied Science (MASc)


title: The Nature and Origin of the Deposits in Canyons of the Ram Plateau, Northwest Territories, Canada

contributor:
Ford, D.C.
Geography

subject: Geography Geography

abstract:
Geomorphological mapping and sediment analysis of unconsolidated deposits in the canyons of Ram Plateau, Mackenzie Mountains, N.W.T was undertaken during the summers of 1976 and 1977. Evidence was found for four major Laurentide ice advances. Ice-dammed proglacial lake phases are associated with each of the latter three.

During the early stages of canyon development, a massive ice sheet covered the area (Nahanni Glaciation) depositing a till with shield erratics on the plateau surface. After a lengthy erosional phase, ice passed through breaches in Nahanni Range and advanced to the eastern flank of Ram Plateau (Sundog Glaciation). This impounded Lake Sundog, in Sundog Basin and Ram Canyon, resulting in infilling to 730 m a.s.l. Following a period of extensive dissection, a third ice sheet advanced to Ram Plateau, and alluvium was deposited up to 550 m a.s.l. in Ram Canyon and its tributaries by the impounded Lake Ram. Two stands during withdrawal are evidenced by deposits along the eastern flank of the plateau at 460 m a.s.l and 380 m a.s.l. The most recent ice sheet advanced as far as Nahanni Range (Tetcela Glaciation) and sediment was deposited to 210-275 m a.s.l. in Tetcela Basin by the impounded Lake Tetcela. This ice sheet is attributed to the "Classical" Wisconsinan glacial stade.

Because Ram Plateau was situated at the front of the last three fluctuating ice masses, remnants of sediments dating from lakes impounded by pre-Wisconsinan ice sheets are preserved, and there has been enough time since the plateau and canyon areas were glaciated for the effects of glacial scour to have been obliterated and the alluvium to be intensely dissected and massively slumped.

abstract: Master of Science (MS)


title: The riddle of the painful earth : the interaction of art and life in the later nineteenth century

contributor:
Ferns, John
English

subject:
English Language and Literature
English Language and Literature

abstract: Master of Arts (MA)


title: Aesthetic experience

contributor:
Georgiadis, Constantine
Philosophy

subject: Philosophy Philosophy

abstract: Master of Arts (MA)


title: Kroetsch's tragicomic romance : the Out west trilogy

contributor:
Hallstadt, C.P.
English

abstract: Master of Arts (MA)


title: A comparison of the transcendent qualities of leisure and religion

contributor:
Mol, Hans
Education

subject:
Education
Educational Sociology
Educational Sociology

abstract: Master of Arts (MA)


title: Into the farther timber

contributor:
Brasch, J. D.
English

subject:
English
English Language and Literature
English Language and Literature

abstract: Master of Arts (MA)


title: The structure of In memoriam : the closing cycle rich in good

abstract: Master of Arts (MA)


title: Strongly homogeneous spaces

contributor:
Banaschewski, Bernhard
Mathematics

subject: Mathematics Mathematics

abstract: Master of Science (MS)


title: Albumin-polyethylene surface interactions

contributor:
Brash, J.L.
Engineering

subject: Engineering Engineering

abstract: This thesis reports on experimental investigations of the surface reactions between human albumin and polyethylene (medical grade). Radioactive tracer technique was used in investigating these reactions. Albumin adsorption and turnover kinetics to polyethylene were studied under both static and flow conditions. Shear rates was not found to affect the kinetics and steady state surface concentration levels of protein adsorption within the range of shear studied (0-2500 Sec⁻¹). Turnover showed dependence on shear rate. Compartmental analysis and non-linear parameters estimation theory were used to estimate the kinetic parameters of the turnover process. The study deals with the relation between these findings and the problem of thrombogenesis induced by blood-foreign surface contact.

abstract: Master of Engineering (ME)


title: Persons, identity and individuation

contributor:
Shalom, A.
Philosophy

subject: Philosophy Philosophy

abstract: Master of Arts (MA)


title: Polymerization of Vinyl Chloride

contributor:
Brash, J.L.
Hamielec, A.E.
Chemical Engineering

abstract:
Therein is reported an experimental evaluation of a model after Abdel-Alim and Hamielec, for bulk and suspension polymerization of vinyl chloride for the conditions of nonisothermal polymerization and polymerization with multiple initiator systems.

The model predictions for these rather extreme conditions are reasonable. It appears that with minor modifications the model could be used to design initiator systems and to develop new molecular weight recipes for commercial initiators.

abstract: Master of Engineering (ME)


title: OPERATORS ON LEBESGUE SPACES WITH GENERAL MEASURES

contributor:
Heinig, H.P.
Mathematics

subject: Mathematics Mathematics

abstract: This thesis is concerned with the study of integral operators of the form [equation removed] between Lebesgue and "weak" Lebesgue spaces with general measures. For large classes of kernels we characterize the measure μ and v for which the operator [equation removed] or [equation removed] 0

abstract: Doctor of Philosophy (PhD)


title: Sequence dependence of stability and intercalation studies on short synthetic oligoribonucleotide duplexes

contributor:
Neilson, T.
Biochemistry

subject: Biochemistry Biochemistry

abstract: A phosphotriester synthesis was used to prepare short oligoribonucleotides for study by variable temperature H-NMR. The duplex = single strand transition was monitored by the associated changes in chemical shift and coupling constant for the ribose base, imino, and anomeric protons. A measurable parameter of stability, the melting temperature (Tm), was extracted from the chemical shift versus temperature data. The sequence dependence of stability was studied for a series of tetramer sequences comprising exclusively guanosine and cytidine residues. These sequences formed perfect duplexes with stabilities: (GGCC)₂ > (GCGC)₂ > (CCGG)₂ ≅ GCCG:CGGC > (CGCG)₂, which led to a ranking of stabilities of nearest neighbour interactions: GC:GC ≥ GG:CC > CG:CG. Study of complementary mixtures of GC-rich trimers in the presence and absence of salt revealed a highly salt dependent self-aggregataion of the G-rich strand. A structure for the GCG aggregate is proposed. Studies of stability and structure of base-base mismatches in GC-rich oligoribonucleotides were performed on six pentaribonucleotides derived from the GC tetramers. Two sequences, CCAGG and GCUGC, formed duplexes of comparable stability, containing AxA and UxU mismatches respectively. The mismatched bases stacked into the duplex. One sequence, GGACC, did not duplex; the others (GGUCC, CCUGG, GCAGC) formed structures not incorporating mismatched base pairs. Mixing experiments on the complementary pentamers (e.g., GGACC:GGUCC) allowed study of the effect of introduction of A•U base pairs on the GC tetramer stability. Interealation of proflavine into the mismatch containing duplexes CCAGG and GCUGC (and their parent duplexes CCGG and GCGC) was studied to compare interealation into mismatch and non mismatch sites. Addition of increasing ratios of proflavine produced a steady increase in Tm and shielding for most protons, but there is no indication of site preference or looping out of mismatched bases. GCUGC tabled a threefold higher Tm increase than GCGC, but the starting Tms are too widely separated to allow direct comparison of binding affinities.

abstract: Doctor of Philosophy (PhD)


title: SUPERCONDUCTIVITY IN MAGNETIC AND PROXIMITY EFFECT SYSTEMS

contributor:
Carbotte, J.P.
Physics

subject: Physics Physics

abstract: Some aspects of the theory of superconductors containing paramagnetic impurities in the model of Shiba and Rusinov (SR) are examined. The critical magnetic field deviation function is shown to be very sensitive to the SR scattering parameter ∊₀ with the behavior of D(t) correlated with the zero frequency density of states and improved agreement is found with experiment Zn-Mn as compared to the predictions of the theory of Abrikosov and Gor'Kov (AG). Optical absorption and thermal conductivity experiments involving a variety of transition metal alloys are reanalyzed including up to three scattering phase shifts with no significant improvement found over the agreement obtained with only a single phase shift. The electromagnetic coherence length with SR impurities is also considered. Model calculations for superconducting spin-glasses show that systems such as GdᵪCc₁₋ᵪRu₂, which exhibit significant deviations from the AG prediction for the reduction of the critical temperature with impurity concentration are also expected to exhibit significant deviations from AG behavior for the temperature variation of properties such as the thermodynamic critical field and the electromagnetic penetration depth. The model of Lee for reentrant ferromagnetic superconductors is shown to be only in qualitative agreement with the temperature dependence of the free energy difference and thermal conductivity determined experimentally for ErRh₄B₄. This model is not in agreement with the measured peak in ultrasonic attenuation at higher temperature. A variety of properties of proximity effect junctions are considered within the McMillan model. The free energy difference is shown to be given by the standard Bardeen-Stephen result applied to both sides of t he junction. The temperature dependence of the free energy difference differs significantly from that of a BCS superconductor with the deviation function becoming much more negative than the BCS predictiton. Both the free energy difference and the specific heat jump are suppressed by increasing normal film thickness or the addition of paramagnetic impurities and this behavior is relatively insensitive to the details of scattering as described by the SR scattering parameter ∊₀. The optical absorption of the normal side of a proximity effect junction is found to have a small structure associated with the two peaked structure of the density of states predicted by the McMillan model, with the effect of SR model impurities qualitatively the same as in the intrinsic case. The electromagnetic penetration depth at low temperature is found to be quite sensitive to the addition of paramagnetic impurities as well as to the SR scattering parameter ∊₀. Finally, the temperature dependence of the zero bias tunneling conductance of a proximity effect induced superconducting spin-glass is calculated and shown to be in reasonable agreement with experiments involving Ag-Mn.

abstract: Doctor of Philosophy (PhD)


title: Rootlessness and alienation in West Indian literature

contributor:
Dale, James
Warner, Gary
English

abstract: Master of Arts (MA)


title: Dickens and the family : a study of parent-child relationships

contributor:
Petrie, G.
English

abstract: Master of Arts (MA)


title: The Foundations of Freedom in Leibniz's Metaphysics

subject: Philosophy Philosophy

abstract:
This thesis is an investigation of the nature and foundation of freedom in Leibniz's self-avowedly deterministic metaphysics. The carrying out of this investigation requires an over-all evaluation of Leibniz's Rationalism. This evaluation is obtained by placing Leibniz in the perspective provided by an examination of Rationalism's prior development in the thought of Descartes and Spinoza.

Throughout the thesis, as a results of this particular approach, attention is focussed not only on Rationalist metaphysics, but on methodology as well, especially in terms of how the two reflect each other.

The thesis concludes by presenting the nature of freedom, and of Leibniz's Rationalism generally, as springing from the fundamental ambiguity of the relationship between the laws of reason and God (viewed as both the source of Creation and the object of worship). As such, the relationship between freedom and determinism in Leibniz's philosophy must be regarded as depending finally on unclarified aspects of his ontological views.

abstract: Master of Arts (MA)


title: Mechanisms of copper toxicity and acclimation to copper in rainbow trout (Salmo gairdneri R.)

contributor:
McDonald, D.G.
Physiology and Pharmacology

subject: Physiology Physiology

abstract: Experiments were conducted on rainbow trout to analyse 1) the physiological mechanisms of short-term copper toxicity, 2) the effects of water hardness, pH, and alkalinity on copper toxicity, and 3) the physiological and biochemical mechanisms of acclimation to copper toxicity. Unidirectional and net sodium fluxes were the basic parameters measured. Disruption of the ionoregulatory functions of the gill accounted for short-term (24 h) and long-term (28 day) copper toxicity. Copper inhibited sodium uptake at concentrations as low as 12.5 μg/L, and stimulated sodium efflux at copper concentrations greater than 100 μg/L. High alkalinity water (i.e., 1000 μM Ca(CO)₃) significantly reduced copper effects on both sodium uptake and sodium efflux. Although water hardness (i.e., 25 vs. 1000 μM Ca(NO₃)₂) had no effect on sodium uptake (at either pH 7.8 or pH 5.0), hardwater fish were better able to reduce sodium efflux than softwater fish. At pH 5.0 (in both hard and softwater), a significant additional inhibition of sodium uptake was found at low levels of copper but not at higher levels. Juvenile trout were about twice as sensitive to copper as adult trout. Juvenile trout were able to acclimate to 55 μg/L copper. Acclimation was defined as the return of sodium uptake and whole body sodium to control levels during continuous exposure to copper. Sodium uptake kinetics and whole body sodium concentration were analysed weekly during 4 weeks of exposure. The recovery of sodium uptake took about 3 weeks to complete, but whole body sodium recovered within 1 week. The time necessary for the recovery of influx was provided by a reduction in efflux. The inhibition and recovery of sodium influx was correlated with the inhibition and recovery of the Na⁺-K⁺-ATPase transport pool of the gill. Metal binding proteins played no apparent protective role in the recovery of Na⁺-K⁺-ATPase. Metal binding proteins were induced in the liver, but a significant portions of the whole body copper burden was accumulated by other tissues.

abstract: Doctor of Philosophy (PhD)


title: A theoretical study of slag-metal reaction kinetics using a numerical technique

contributor:
Lu, W. K.
Metallurgy and Materials Science

subject:
Materials Science and Engineering
Metallurgy
Materials Science and Engineering

abstract: Currently available theoretical formulation for the kinetics of slag-metal systems have been extended to clarify certain aspects of the system. Coupling factors for electrochemical reactions and for ionic diffusion have been defined to clarify the significance of coupling phenomena in the kinetics of multi-component systems. Theoretical equations for the interfacial reactions and the diffusion processes in both phases, in seven hypothetical pseudo-ternary slag-metal systems have been numerically solved by a finite difference method. Typical features of coupling phenomena, i.e.m acceleration and deceleration of reaction or diffusion, and up hill reaction or diffusion have been clearly demonstrated. Through numerical analysis, a modified form of "Sherwood Number", Shᵢ*≡kᵢL/ρDᵢ for a particular reaction i, is defined and found to be proper to explain the rate controlling steps for the over-all reaction. In the present analysis, the relationships between the modified Sherwood Number and rate controlling steps were found to be as follows: Sh*ᵢ > 360: diffusion control, 0.05 ≲ Sh*ᵢ ≲ 360: mixed control, Sh*ᵢ < 0.05: interfacial reaction control Thus non-trivial numerical solutions for slag-metal systems have been developed for the first time.

abstract: Master of Engineering (ME)


title: The demon-slaying Devi: A study of her puranic myths

contributor:
Kinsley, David
Religious Studies

abstract: Master of Arts (MA)


title: Effects of 6-hydroxydopamine on plasma gonadothrophin levels in male rats

contributor: Medical Sciences (Design, Measurement, and Evaluation)

subject:
Medical Sciences
Medical Sciences

abstract:
A. The involvement of central catecholaminergic neurons in tonic gonadotrophin release in male rats was investigated.

(i) Animals were given a single intraventricular injection of 6-hydroxydopamine hydrochloride (6-ODHA; 170 μg free base) dissolved in 0.001 N HCl. Plasma LH and FSH were measured by double antibody radioimmunoassay. LH in the 6-OHDA treated animals was significantly reduced after one hour and remained consistently lower for eight hours. The controls, after a transient elevation, showed no significant change. No difference in LH concentrations was found between experimental groups sampled at two days or later. FSH in treated animals showed less consistent difference from the controls.

(ii) Animals given an intraventricular injection of 6-OHDA dissolved in different vehicles, with varied pH and osmolarity, gave similar LH and FSH results which suggests the quinone derivative of 6-OHDA is effective in producing the catecholaminergic impairment.

(iii) Administration of 6-OHDA dissolved in different vehicles, with varied pH and osmolarity, gave similar LH and FSH results which suggests the quinone derivative of 6-OHDA is effective in producing the catecholaminergic impairment.

These findings indicate the LH release in the male rat may be controlled (or at least modulated) by a central adrenergic mechanism.

B. The involvement of the ventral noradrenergic ascending pathway in tonic gonadotrophin release was investigated. Bilateral injection of 6-hydroxydopamine hydrochloride given into the preoptic area of the medial forebrain bundle significantly reduced plasma LH at all times tested. Plasma FSH was not significantly different. These results suggest that tonic LH release is modulated by an extrahypothalamic mechanism.

C. The hypothalamic catecholamine content was pharmacologically manipulated with various drugs.

(i) An intraperitoneal injection of protriptyline was given before 6-OHDA in order to selectively reduce the hypothalamic content of dopamine. Plasma LH, but not FSH was significantly reduced 3 hours after 6-OHDA in animals pretreated with protriptyline compared to controls. Neither plasma nor testicular testosterone were significantly different between groups.

(ii) Animals given DL-threo-dihydroxyphenylserine showed a significant increase in plasma LH (previuosly decreased by 6-OHDA) compared to controls. DL-threo-dihydroxyphenylserine selectively restores the noradrenaline content in the hypothalamus.

(iii) γ-Butyrolactone blocks the central release of dopamine and produces anaesthesia resembling deep sleep. No consistent significant differences were found in either plasma LH or FSH at any of the times or doses tested in animals given either γ-butyrolactone or a metabolite, γ-hydroxybutyric acid, compared to the control group receiving saline injection alone.

(iv) 6-hydroxydopa which selectively reduces brain noradrenaline content, had no effect on plasma LH and FSH.

The above findings give further support to the concept of modulation of tonic gonadotrophin release by an extrahypotalamic noradrenergic mechanism.

abstract: Doctor of Philosophy (PhD)


title: Engagement between mothers with children at-risk of developmental delays, public health nurses and family visitors in a blended home visiting program

contributor:
DiCenso, Alba
Clinical Health Sciences (Nursing)

subject:
Clinical Health Sciences Nursing
Nursing
Nursing

abstract: [missing pages 18 and 96]

abstract: This sandwich thesis summarizes the findings from two qualitative studies exploring the process of engagement among mothers with children at-risk for developmental delays, public health nurses (PHN) and family visitors (FV) in a blended home visiting program. The purpose of the phenomenological study (study #1) was to identify and describe factors which influence the establishment of a working relationship between FVs and at risk families. In-depth, semi-structured interviews were conducted with a purposeful sample of six FVs and six PHNs. The analytic process revealed that PHNs have an important role in marketing home visiting programs and facilitating FV access into the home. Family visitor-client engagement occurred through "finding common ground" and "building trust." The purpose of the grounded theory study (study #2) was to explore the process of engagement from the client's perspective. In-depth, semi-structured interviews were conducted with a purposeful sample of 20 mothers who were receiving PHN and FV home visits. Clients engage with home visitors through a basic social psychological process of limiting family vulnerability. This process has three phases: (1) overcoming fear, (2) building trust, and (3) seeking mutuality. The personal characteristics, values, experiences, and actions of the PHN, FV, and mother influence the speed at which each phase is successfully negotiated and the ability to develop a connected relationship. Client characteristics that influence engagement include: preconceptions of PHNs and FVs, past experiences with service providers, motivation to participate, client attachment style, and the identification of specific health related needs. Remaining engaged in home visiting is influenced by family beliefs about the value of the visits and the client's ability to identify short-term benefits related to working with either the PHN and/or FV. Increased understanding of these factors will assist both PHNs and FVs access those families who are hard-to-reach and resist support and services.

abstract: Doctor of Philosophy (PhD)


title: Semiconducting and dielectric properties of barium titanates, tantalates and niobates with perovskite structure

contributor:
Petric, Anthony
Materials Science and Engineering

abstract: The dielectric and semiconducting properties of two types of ceramics (n-type BaTiO₃ and dielectric Ba(B'⅓ B''⅔ )O₃ where B' = Mg, Zn, Ni, and B'' = Nb₁ Ta) were characterized. Complex impedance analysis and dc conductivity measurements of samples prepared at various [Special Characters Removed] have ruled out oxygen chemisorption in favor of interfacial segregation of cation vacancies as the cause of the positive temperature coefficient of resistivity (PTCR) effect in n-type BaTiO₃ . The effect of preparation conditions, sintering atmosphere, stoichiometry, and post-sinter anneal on the defect chemistry of BaTiO₃ was studied using the electron paramagnetic resonance (EPR) technique. Several paramagnetic defects such as, Ti³⁺ , [Special Characters Removed] were detected and identified by EPR. Current-voltage characteristics (I-V ) of PTCR BaTiO₃ were analyzed in light of space-charge-limited-current, trap-filled-limited-current, Frenkel-Poole, small polaron, and double-Schottky barrier models. It was shown that for the double-Schottky barrier model, a partial stabilisation of the potential barrier is expected when the Fermi level is pinned at grain boundaries by a high density of the interface states. The deviation of I-V characteristics of BaTiO₃ in the region of the PTCR effect can be explained by dependence of the population of the interface electron states on applied voltage. Based on the Seebeck and Hall effect measurements, it was found that in the range of 100-300 K, the drift mobility of electrons in BaTiO₃ is not thermally activated, which supports the concept of conduction band electron transport rather than small radii polaron hopping. However, further study over a wider temperature range and on better quality crystals is required to unequivocally clarify the electron transport mechanism in BaTiO₃ . Phase composition, degree of cation ordering, and dielectric properties of complex perovskites with general formula Ba(B' ⅓ B''⅔ )O₃ where B' = Mg, Zn, Ni, and B'' = Nb₁ Ta were analyzed. It was shown that in Ba(Mg⅓ Ta⅔ )O₃ both intrinsic and extrinsic dielectric loss affect the Q-factor, whereas in Ba(Mg⅓ Nb⅔ )O₃ and Ba(Ni⅓ Nb⅔ )O₃ extrinsic factors such as the second phase and point defects dominate the dielectric loss at microwave frequencies.

abstract: Doctor of Philosophy (PhD)


title: Absorption Properties of SF₆ near 10.6 µm

contributor:
Garside, B.K.
Ballik, E.A.
Physics

subject: Physics Physics

abstract:
The work described in this thesis concerns the investigation of the absorption properties of SF₆ in the 10.4 µm band of CO₂ lasers. Although SF₆ has been used frequently as a saturable absorber in CO₂ laser systems, the complex dynamical behaviour of its absorption not understood prior to our work. A model is developed which allows for the multilevel nature of the absorption processes. This model treats all the SF₆ vibrational and rotational levels as belonging to a bath of levels characterized by single vibrational temperature and a single rotational temperature. Energy absorbed from a laser pulse is rapidly distributed throughout this bath, establishing a new vibrational population distribution characteristic of the higher vibrational temperature.

The vibrational equilibrium is readily maintained at high SF₆ pressures. It is demonstrated that in this case the model successfully predicts the transmission and pulse shaping of high power CO₂ laser pulses. In particular, the rapid decrease in absorption at high incident intensities is shown to be due to vibrational heating and not to any intensity saturation process. Dissociation which occurs as a result of sufficient vibrational heating is discussed. The effect of dissociation on single pulse transmission is determined through simple modifications of the model.

The model is also shown to have application to low SF₆ pressures. Previous investigations concerning vibrational relaxation rates in SF₆ would indicate that vibrational equilibrium cannot be maintained in such a situation. More recent results show that in fact sufficiently rapid vibrational energy exchange can occur. The final portion of this thesis discusses the dependence of these rates on the vibrational energy of the molecules. An approximate, but conceptually simple, method of incorporating these effects into the model is described. In conclusion, it is shown that the model is capable of determining the SF₆ absorption behavior for a wide range of SF₆ pressures and CO₂ laser wavelengths when both intensity saturation and vibrational heating effects are included.

abstract: Master of Science (MS)


title: Modelling of mechanical behaviour of concrete structures

contributor: Civil Engineering and Engineering Mechanics

subject:
Civil Engineering
Engineering Mechanics
Civil Engineering

abstract:
This thesis deals with numerical modelling of mechanical behaviour of reinforced concrete structures. The main objective of this study is to establish a rational constitutive model for concrete subjected to monotonic or cyclic loadings and to analyze nonlinear behaviour of reinforced concrete structures by finite element method.

The constitutive model described here is built within the framework of rate-independent theory of plasticity. In the present study, the emphasis is placed on an adequate modelling of basic trends in the behaviour of concrete, e.g. compaction-dilatancy transition, sensitivity of material characteristics to confirming pressure, gradual transition in failure mechanisms from a brittle to a ductile mode and phenomenon of cyclic degradation of material stiffness and strength, etc. The proposed model is suitable for describing strain hardening and softening response of concrete under any complex state of stress. In order to describe rigorously the strain softening response, an appropriate criterion for strain localization is derived from considerations of stability of the constitutive relations. The model is verified for a number of loading paths by comparing the numerical results with the experimental data available in the literature.

The finite element modelling of reinforced concrete slabs is also presented. In this finite element model, the post-cracking behaviour of concrete and tension stiffening effect are modelling using the proposed constitutive theory. Moreover, some common problems relared to numerical instability are carefully studied. The nummerical results are compared with the experimental data and the results obtained from other analytical models.

abstract: Doctor of Philosophy (PhD)