title: Synthesis and Evaluation of Model Initiator / Reversible Terminating Adducts for the Stable Free Radical Polymerization Process

contributor:
Stover, Herald D.
Chemistry

subject: Chemistry Chemistry

abstract: This thesis describes the synthesis, characterization and evaluation of model initiator/reversible terminating agents, to enhance the fundamental understanding of the stable free radical polymerization process. One portion of this research, involved AM1 and PM3 semi-empirical molecular orbital calculations on a model SFR reaction. The aim of this work was to identify new nitroxyl radicals with a labile C-O bond, but it became apparent that semi-empirical MO calculations were not accurate enough to differentiate between various nitroxyl radicals. To calibrate the MO calculations and determine where the deficiencies in the methods were, the single crystal X-ray structure of MB-TMP was obtained. A series of alkoxy and aryloxy-tetramethylpiperidine compounds, RO-TMP were prepared by the reaction of tri-n-butyl tin hydride with various alkyl or aryl halides and TEMPO. Using the same synthetic route, the 1-phenylethyl carbon radical fragment was trapped by 1,1,3,3-tetramethyl- and 1,1,3,3-tetraethylisoindoline nitroxide to form MB-TMI and MB-TEL. All compounds were isolated, purified and characterized by ¹H and ¹³C NMR spectroscopy. Using ESR spectroscopy, the enthalpy of activation to homolytically cleave the C-O bond in ten of the nitroxide adducts was measured. In the adduct series, MB-TMP, MiP-TMP and EiB-TEMP which mimic the styrene, acrylate and methacrylate monomers respectively, the enthalpy of activation decreased from 131.2 ±7.2, 125.3 ±5.4 to 119.2 ±3.4 kJ/mol, respectively. This indicated that the C-O bond strength between the propagating polymer chain end and TEMPO is the weakest for a methacrylate monomer with increasing C-O bond strength for acrylate and styrene monomers. Steric bulk of the tertiary methacrylate radical carbon contributed to a weaker and more labile C-O bond. In the series of initiating carbon radicals bonded to TEMPO, it was demonstrated that increasing the steric crowding about the carbon radical decreased the enthalpy of activation to break the C-O bond. Also, when steric bulk was increased on the alpha carbons to the nitroxyl functional group in the tetraethylisoindoline nitroxide, the C-O bond in 1-phenylethyl-tetraethylisoindoline adduct, MB-TEI was 4.7 kJ/mol weaker than in MB-TMI. The thermal decomposition of nitroxide adduct MB-TMP was measured as a function of time at 125℃ by ESR and ¹H NMR spectroscopy. As a result of this kinetic study, an alternative mechanism to that of Li et al. was proposed for possible polymer chain termination when the excess nitroxide in the polymerization system builds up. All major products from the thermal decomposition of MB-TMP were identified and the effect of oxygen in the polymerization via autoxidation mechanism was observed. This study has identified that hydrogen radical abstraction by a significant excess of TEMPO can produce a terminal vinyl group at the end of a polystyrene chain. In the presence of oxygen and excess TEMPO, a phenyl ketone functional group can also be produced to terminate a polystyrene chain end. Two nitroxide adducts, MB-TMP and B-TMP and the unimer BST were evaluated as initiators and as the only source of nitroxyl radical in the bulk polymerization of styrene by the stable free radical polymerization process. The C-O bond in B-TMP did not cleave at a fast enough rate to enable a controlled SFR polymerization. Instead, polystyrene chains were self-initiated by the Mayo mechanism resulting in a conventional free radical polymerization process. The initiating efficiency of MB-TMP was found to be equivalent to BST and a controlled "living" stable free radical polymerization with narrow polydispersities demonstrated. The alpha-methyl group on the benzylic carbon in MB-TMP was responsible for increasing the steric bulk around the C-O bond and making the bond more labile. The addition of excess nitroxide decreased the rate constant of propagation and lowered MWD during the initiation period of polymerization.

abstract: Doctor of Philosophy (PhD)


title: The Quantification of "Happiness" in Utilitarianism

contributor:
Thomas, J.E.
Philosophy

subject: Utilitarianism Philosophy Philosophy

abstract: Utilitarianism is the theory that morality should be governed by the aim of "maximizing satisfaction" is a highly problematic one. This thesis attempts to resolve the difficulties. After an introduction opening chapter, the main discussion begins with a defence of the hedonistic concept of "satisfaction" in terms of pleasure and the absence of pain, in oppositions to the currently more prevalent preference-oriented approach. An attempt is then made to explicate the concept of the "intensity" of a pleasure or pain. An important consequence of the discussion is that pleasure and pain cannot in fact be put on the same metrical scale. Utilitarianism is thus seen really to have two separate components-- a positive one, concerned with pleasure; and a negative one, concerned with suffering. These need to be clearly distinguished, although they will be isomorphic with respect to the solution of the maximization problem. The discussion of this problem begins in Chapter Three. It is argued that conventional solutions-- particularly Total Utilitarianism and Average Utilitarianism-- are inadequate. The extreme view that "numbers do not count" is also considered and rejected. The fourth chapter contains my own proposal. According to the latter, the concepts of "more pleasure" and "less suffering" are not unitary in character, but are to be understood in terms of a multiplicity of principles of varying degrees of validity. The concluding chapter discusses some outstanding difficulties and attempts to place the theory in a broader context. Further technical elaboration of certain aspects of the theory is contained in two appendices to the thesis.

abstract: Doctor of Philosophy (PhD)


title: Opportunities for Foreign Trade and the Extent of Suboptimal Capacity in Canadian Manufacturing Industries

contributor:
Muller, R.A.
Robb, A.L.
J.D. Welland and J.R. Williams
Economics / Economic Policy

abstract: This dissertation examines the impact of trade barriers on suboptimal capacity in Canadian manufacturing industries in 1968, 1970 and 1979. Suboptimal capacity (i.e. failure to realize scale economies) is a frequent explanation of persistent low productivity levels in Canada relative to the US. The basic question addressed in this thesis is whether small markets prevent scale efficiency in Canada, and if so, how? In this regard a model of the determination of plant scale in a homogeneous goods industry protected by tariffs is developed. The model allows for free entry and the solution concept in Cournot-Nash Equilibrium. Three hypothesis are tested: the small market hypothesis, the trade liberalization hypothesis, and the Eastman-Stykolt hypothesis. The trade liberalization hypothesis predicts that US-Canadian trade barriers promote scale inefficiency by separating a small Canadian market from the large US market. The Eastman-Stykolt hypothesis predicts that the interaction of small Canadian market size and high trade barriers should lead to more scale inefficiency. These hypotheses are tested on data supplied by the US International Trade Commission and Statistics Canada. The thesis confirms the importance of small markets in explaining scale inefficiency. US-Canada nominal tariff protection and Canadian Non-Tariff Barriers (NTBs) seem to be closely associated with scale inefficiency in Canada. There is some support for the Eastman-Stykolt effect. The thesis concludes that the Canadian producers would realize economies of scale if Canada trade protections and US tariffs are reduced. Many studies have documented these effects but our study is the first to explicitly deal with NTBs. The key contributions are: (a) improved modelling of the effect of trade barriers on plant scale, and (b) improved test of the Eastman-Stykolt hypothesis.

abstract: Doctor of Philosophy (PhD)


title: Modules in which Complements are Summands

contributor:
Mueller, Bruno J.
Mathematics

subject: Mathematics Mathematics

abstract: This thesis studies modules over commutative integral domains with the property that every closed submodule is a direct summand (we denote this property by (C₁)). It is shown that any non-torsion module with property (C₁) is a direct sum of an injective submodule and a finite direct sum of uniform torsion free reduced submodules. This reduces the study of the problem to finite direct sums of uniform torsion free reduced modules and to torsion modules. Then we characterize finite direct sums of uniform torsion free reduced modules over commutative (Prüfer, Noetherian of Krull dimension one, Dedekind) domains which have property (C₁). We also characterize finite direct sums of uniform torsion modules with local endomorphism rings over Noetherian domains which have property (C₁). Finally, we classify all modules with property (C₁) over Dedekind domains.

abstract: Doctor of Philosophy (PhD)


title: Contaminant Leaching From Cement-based Waste Forms under Acidic Conditions

contributor:
Benedek, Andrew
Civil Engineering

subject:
Civil Engineering
Civil Engineering

abstract:
A waste form can be prepared by mixing a hydraulic cement and, if needed, a bulking agent with an aqueous waste to cause it to solidify. A mechanistic leaching model was developed based on describing the chemistry of the waste form-Ieachant system and the flow regime of the leachant and assuming that transport takes place via diffusive exchanges through the waste form-Ieachant Interface. This model was successful in predicting Ieaching from simpIe waste matrices and in identifying important containment mechanisms effective in the more complex matrices.

The cement-based waste forms studied had porosities ranging from 40 to 60%. Portland cement provided acid neutralization capacity to maintain the high pH environment where the waste form is stable; a typical waste form contains enough cement to neutralize between 2000 to 3000 times its volume of a pH 3 leachant.

In a mild environment, leaching was controlled by the diffusion of the soluble fraction of a contaminant present in the connected pores of the matrices. Immobile species instantaneously solubilized to maintain chemical equilibrium between the soluble and insoluble fractions. In tests conducted over a period of almost 2 years, less than 1% of the initial amount of cadmium, chromium and lead contained in a specimen leached out.

In an acidic environment, the leaching rates were limited by the availability of acid to dissolve the matrix. The leaching process was similar to a surface corrosion process. However, since waste matrices are not completely soluble in a mild acid, a leached layer develops, eventually protecting the core of the waste form from direct contact with aggressive groundwaters. Contaminants solubilized at the leaching front are subjected to concentration gradients that force them to diffuse both inward and outward. Only a fraction of the total concentration therefore leaches out.

The mechanistic knowledge developed through the experimental programme and the modelling effort was used to develop eight long term leaching scenarios covering a wide range of waste form and groundwater conditions. In addition to allowing the prediction of leaching rates for periods of up to 100 years, these scenarios were useful in developing recommendations to prepare more efficient waste forms and design better landfills.

abstract: Doctor of Philosophy (PhD)


title: Model Based Die Cavity Machining Simulation Methodology

contributor:
Elbestawi, M.A.
Mechanical Engineering

subject:
Mechanical Engineering
Mechanical Engineering

abstract: The current emphasis of CAD/CAM technology, in particular the die and mold manufacturing sector, is to verify and optimize the NC code in terms of the productivity and machining accuracy prior to the actual machining. Also, there is a trend towards enhancing the on-line control strategies with the technological data. However, the intricate geometry with sculptured surfaces which is found nowadays in most of dies and molds, together with relative high material hardness, makes the NC verification/optimization process a very demanding and difficult task. In this regard, the development of model-based simulation methodology with functions of geometrical and physical modeling is a fundamental advancement in improving productivity, accuracy, and automation. In the course of the thesis presented, a new model-based simulation methodology for die cavity milling operations is developed. The comprehensive and realistic simulation of the milling process is implemented in the form of an integrated geometrical/physical/interaction environment. The geometric sub-environment constructs the volume swept by the cutter (or the surface swept by the cutting edge), accurately updates the model of the stock as the cutter removes the material, and automatically extracts the immersion geometry from the updated model. Based on the knowledge of the material remaining on the surface, two- and three-axis tool paths are computed. In the semi-finishing operation, a three-axis milling strategy is developed to control the scallop height remaining on the surface and avoid cutting with the dead zone of the cutter. The physical/mechanical sub-environment, integrated with the geometric counterpart, consists of a newly developed force model as well as a mathematical model of tool-structure dynamics. The integrated environment can accurately simulate the closed loop of the machine tool-cutting process. It predicts the instantaneous cutting forces, tool tip deflections, and the onset of chatter vibrations. The finishing operation is simulated based on the true path of the cutting edge. The method developed is able to construct the geometric model of feed marks and scallops remaining on the surface. Experimental measurements confirm the validity of the implemented methodology. First, the chip geometry is extracted, the part is updated, and the NC codes are verified for two- and three-axis milling of free-form surfaces. Second, the instantaneous cutting forces, tool tip deflections, the onset of chatter vibrations are predicted and compared with the experimental measurements. Next, a new three-axis milling strategy is implemented to control the scallop height and avoid cutting with the dead zone of the cutter. Lastly, the model of feed marks and scallop height are constructed, the feed mark profile is extracted and compared with the measurement. The developed system enhances the capabilities of the CAM/CAM systems in terms of increased productivity, improved machining accuracy, and heightened the level of automation

abstract: Doctor of Philosophy (PhD)


title: Dynamic, Multinuclear NMR Spectroscopy of Transition Metal Complexes

contributor:
Eaton, D.R.
Chemistry

subject: Chemistry Chemistry

abstract:
The use of NMR spectroscopy in inorganic chemistry is growing steadily as high-field, (multinuclear, sophisticated NMR spectrometers become more readily available. NMR of transition metal complexes is developing rapidly as metal nuclei as well as nuclei of ligating atoms become more popular candidates for NMR experiments. In this thesis, dynamic, multinuclear NMR spectroscopy has been carried out on various complexes of Cobalt(III) and Zn(II) as well as on free ligand molecules found in these complexes.

The second-sphere hydrogen-bonding interaction with the hexacyanocobaitate(III)anion of substituted phenols, anilines, and benzoic acids has been studied by monitoring Co-59 NMR chemical shifts and linewidths. Analysis of the chemical shifts in order to estimate equilibrium constants has been attempted. The second-sphere complex with para-nitrophenol has also been studied by measuring H-1 and C-13 Ts. It is shown that the lifetime of the complex is longer than its rotational correlation time indicating a complex of possible mechanistic significance.

The hexanitrocobaltate(III) anion has been studied by Co-59 NMR, IR and Raman spectroscopies in the solid state and by Raman, Co-59, N-14 and 0-17 NMR, and UU-vis spectroscopies in solution. A comparison of the solid-state and solution results has shown that all six ligands are N-bonded. The primary decomposition step is concluded to be aquation with a lifetime of about three minutes. A charge transfer mechanism is suggested to explain this anomalously high rate of reaction. Analysis of the Co-59 NMR chemical shifts and optical data of related compounds shows that the ligand-field stength of the nitro ligand is markedly variable. An empirical model has been developed for predicting Co-59 chemical shifts of nitro-containing complexes and for complexes containing ligands with different orbital reduction factors. Anomalies in the field dependence of the second-order quadrupole effect in the polycrystalline Co-59 NMR of sodium cobaltinitrite are discussed. The shielding anisotropy of the same compound is shown to be less than 10 ppm.

The first application of the Tıɒ method has been made to a metal nucleus, Co-59. Scalar relaxation in cobaltinitrite and trisethylenediaminecobalt(III)has been studied using this technique. Proton Tıɒ measurements have also been carried out to study scalar relaxation in free thiourea and in Zn(tu)₄(ClO₄)₂. The advantages and disadvantages of this method are discussed.

abstract: Doctor of Philosophy (PhD)


title: Boron and strontium isotope study of fluids situated in fractured and unfractured rock of the Lac du Bonnet Batholith, eastern Manitoba

contributor:
McNutt, R. H.
Geology

subject: Geology Geology

abstract: Groundwater from fractured and unfractured rock in the Lac du Bonnet Batholith, Manitoba, has been analyzed for B and Sr isotopes, and ion chemistry. Fluids from unfractured rock (pore fluids) have been sampled by several methods 1) direct sampling of undiluted pore fluids flowing into boreholes; 2) leaching of pore fluids into boreholes filled with distilled deionized water; 3) extraction of intercrystalline fluids from drill cores. Pore fluids can be very saline, up to 100g/L total dissolved solids, and are chemically distinct from fracture waters. They are 1) enriched in radiogenic ⁸⁷Sr, exhibiting ⁸⁷Sr/⁸⁶Sr ratios as high as 0.801; 2) depleted in Sr with respect to Ca having Ca/Sr molar ratio > 918; 3) depleted in Na and Sr with respect to Cl (Na/Cl < 0.18; Sr/Cl < 0.00085); and 4) have low δ¹¹B-values (<13.5%) and low boron concentrations (<0.27 μg/g). In contrast, fracture waters exhibit ⁸⁷Sr/⁸⁶Sr ratios between 0.713-0.734, have an average Ca/Sr molar ratio of 236, Na/Cl ratio of 0.55, and a Sr/Cl ratio of 0.0014. They are also enriched in ¹¹B up to a δ¹¹B-value of 52.7% and have relatively high boron concentrations compared to the pore fluids; as high as 1.57 μg/g. The dissimilarity in compositions between the two groundwater types indicates that two distinct chemical environments are present in the Lac du Bonnet Batholith. The fracture water chemistry is strongly controlled by the dissolution and alteration of minerals, in particular plagioclase. The dominance of plagioclasle dissolution is seen in the Na/Ca molar ratios (5.60), Ca/Sr molar ratios, and Sr isotopic compositions similar to the granite's oligoclase. The fracture waters are interpreted as an open system where chemical equilibrium between groundwaters and rock has not been attained. Boron isotopes in fracture waters exhibit marine-like compositions, however, due to boron's low concentration in the fracture waters relative to seawater and it's relationship to bromide and chloride concentrations in solution, the source of the boton is not considered to be marine in origin. A model is proposed where the exchange of boron between host rock and solution has resulted in boron concentrations and isotopic compositions of the fracture waters reaching a steady state. In contrast, pore fluid chemistry is not controlled by plagioclase dissolution as evidenced by the absence of a plagioclase ⁸⁷Sr/⁸⁶Sr and Ca/Sr molar ratio signature, and low Na/Cr molar ratio. The high Ca/Sr and low Na/Ca ratios are attributed to the formation of albite. The similarity between the isotopic composition of pore fluids and granite indicate that these waters have reached isotopic and chemical equilibrium with the host rock. The pore fluids can, therefore, be considered a closed system. The similarity in salinities of the most saline fluid inclusions (≈200g/L) and the predicted salinities of pore fluids below 1000m depth in the Lac du Bonnet pluton may indicate a genetic link between a pore fluids and fluid inclusions.

abstract: Doctor of Philosophy (PhD)


title: The Relationship Between the Repair of Ultraviolet Light Induced DNA Damage in Human Cells and the p53 Tumour Suppressor

contributor:
Rainbow, A.J.
Biology

subject: Biology Biology

abstract: UV-induced dimers and bulky chemical adducts in DNA are repaired by nucleotide excision repair (NER). Several lesions repaired by NER including UV dimers pose a persistent block to transcription which in turn promotes apoptosis. A specialization of NER, termed transcription coupled repait (TCR), facilitates removal of transcription-blocking DNA damage by a process which is coupled to transcription by RNA polymerase II (RNAPII). It has been proposed that the presence of RNAPII stalled at a lesion facilitates NER by increasing the affinity of repair enzymes for the site of DNA. However, previous results from our laboratory have demonstrated that host cell reactivation of an ultraviolet (UV)-damanged RNAPII transcribed reporter gene is reduced in TCR proficient but global NER deficient fibroblasts. These results indicate that the RNAPII blocked at the site of a UV-induced lesion is not sufficient to promote the preferential repair of that lesion. It was further demonstrated that UV treatment of these cells increased repair of the reporter gene, strongly suggesting that TCR is inducible. In the present thesis, primary human fibroblast strains with well characterized DNA repair phenotypes were used to demonstrate that heat shock enhanced reactivation of reporter gene activity (HSER) and the capacity of UV-irradiated cells to support adenovirus DNA synthesis (viral capacity), reflect TCR of UC-induced DNA damage. HSER requires repair of the transcribed strand of a reporter gene whereas viral capacity requires repair of genomic DNA. HSER and UV enhanced reactivation (UVER) were: dependent on wildtype p53, disrupted in most tumour cell lines examined and deficient in SV40 transformed fibroblasts. These results were confirmed using the viral capacity assay, indicating that TCR of genomic DNA is inducible through a p53 dependent mechanism. The primary activity ascribed to the p53 tumour suppressor gene is transactivation of genes involved in maintaining genome stability. A key downstream target of p53 is the cyclin dependent kinase inhibitor, p21ᵂᵃᶠˡ. This gene product plays a role in mediating p53 dependent G₁ arrest and it has been suggested to play a role in NER. We hypothesized that UV induced activation of p53 is unlikely to result in efficient transactivation of p53 responsiveness genes because UV induced DNA damage blocks transcription. We report here that UV inhibits p21ᵂᵃᶠˡ expression immediately following irradiation. The efficient recovery of p21ᵂᵃᶠˡ expression and subsequent induction of p21ᵂᵃᶠˡ are dependent on TCR of UV induced DNA damage. The delayed induction of p21ᵂᵃᶠˡ expression following UV irradiation is not consistent with the proposed role of ᵂᵃᶠˡ transactivation in NER. The results presented here predict a dose dependent reduction in the efficiency of G₁ arrest following UV. We addressed the consequences of attenuated G₁ arrest on UV sensitivity by transiently expression SV40 large T antigen, polyoma virus large T antigen, E2F-1 and E2F-4 from recombinant adenovirus (Ad) constructs. Expression of these gene products conferred UV sensitivity on normal diploid fibroblasts. In contrasts, stimulation of the p53 dependent G₁ checkpoint pathway with a similar Ad construct expressing p21ᵂᵃᶠˡ led to increased clonogenic survival following UV irradiation. We propose a model in which UV induced lesions lead to increased p53 activity and p53 stimulated DNA repair but persistent DNA damage prevents expression of p53 responsive gene products in a dose dependent manner. In this way, cells with irreparable DNA damage are likely to be eliminated by apoptosis as a consequence of the inability to express anti-apoptotic genes.

abstract: Doctor of Philosophy (PhD)


title: Optimal Allocation of Types and Magnitudes of Geometric Tolerances

contributor:
ElMaraghy, Hoda A.
Mechanical Engineering

abstract: Manufactoring processes generate surfaces with variable dimensions and geometries. The produced surfaces deviate from their nominal geometry and consequently, critical dimensions and clearaces deviate from their designed values when the parts are assembled. Since it is impossible to check whether the functional requirements fall within their allowable range after the assembly process, geometric tolerances are specified on individual features during the design stage such that, parts whose geometric deviations would cause a violation of the functional requirements when assembled to other parts, would be rejected during the inspection process. Therefore, wrong choice of geometric tolerances could lead to either rejecting good parts, or the acceptance of bad parts leading to an assembly that violates functional requirements. Furthermore, tolerance selection is not limited to the magnitudes of the geometric tolerances. Each feature in the assembly has four geometric variations that need to be controlled. These are size, position, form and orientation. Each of these variations, except variation in size, can be controlled by several types of tolerances and the selection of tolerance types affects the percentage of accepted or rejected parts during inspection. This dissertation presents a novel computer-aided method for the synthesis of magnitudes and types of geometric tolerances in mechanical assemblies. Tolerance selection is formulated as a combinatorial optimization problem, where each feature has seven variables. These are the types of tolerances controlling the orientation, form and position variations, the magnitudes of these tolerances as well as the magnitude size tolerance. A new criterion was developed to allocate geometric tolerances which is the minimum mismatch probability defined as the probability of rejecting a part during the inspection processes which satisfy the functional requirements when assembled to other parts, or accepting one violating the functional requirements when assembled to other parts. In order to evaluate the objective function, a probabilistic analysis method, based on Monte Carlo simulation, was developed to calculate the rejection probabilities of assemblies with geometric tolerances. The surface of each feature in the assembly is represented with a number of points where the coordinates of these points are random variables. In each simulation cycle, the coordinates of the surface points are generated using the probability distribution associated with the manufactoring process. The inspection process is then simulated where the geometric deviations on each feature are checked against the specified tolerances. Finally, the functional requirements are checked. Several methods for parts joining were examined and a new genetic algorithms based method is developed to evaluate the maximum and minimum values of critical clearances. The use of genetic algorithms ensures the arrival to the global minimum and maximum values of the clearance. Due to the large number of random variables, and since the probabilistic analysis is used in every optimization step in the tolerance allocation algorithm, two variance reduction techniques are incorporated with the standard Monte Carlo simulation to reduce sample size. A number of genetic algorithms based routines are used for checking geometric deviations on the generated parts. In many cases the evaluation of geometric deviations involve optimization. The use of global optimizers ensures the correct evaluation of deviations and avoids the unnecessary rejection of good parts. The advantage of using genetic algorithms is demonstrated with several examples used by previous researchers. Furthermore, a new parametric surface interpolation method is developed to approximate the actual surface of the manufactured parts and help in the evaluation of some geometric deviations that cannot be evaluated directly using the generated points. The new tolerance allocation method, presented in this dissertation, attempts to fill a void area in the tolerancing research, which is the selection of the "types" in addition to the magnitudes of geometric tolerances. Although the skill of a tolerancing practitioner is still needed to specify candidate tolerance types for each geometric control, the developed robust mathematical formulation of the problem avoids the random human factors in the selection. The proposed methodology can be extended for incorporation within the computer-aided tolerancing systems to assist designers in selecting geometric tolerances.

abstract: Doctor of Philosophy (PhD)


title: The Short-Run Versus Long-Run Tradeoff in Macroeconomic Policy: An Optimal Control Analysis in the Canadian Context

contributor:
Butterfield, D.W.
Denton, F.T.
Kubursi, A.A.
Economics / Economic Policy

subject: Economics Economics

abstract: The intertemporal dimension of macroeconomic policy, which has been largely neglected, constitutes the main focus of this study. Two questions are posed: What are the long-run implications of pursuing a short-run myopic policy, and what are the short-run consequences of long-sighted policy? Is there a tradeoff relationship between the performance of the economy in the short run and in the long run? To answer these questions, an optimal control approach is used. The two principles elements of this approach are: a macroeconomic model describing the functioning of the system under control, and an objective function specifying explicitly the targets pursued by the policy maker. A macroeconomic model for Canada is formulated and estimated for the period 1962-1982. Some short-run and long-run features characterize the structure of the model. In particular, a government budget constraint, a capital accumulation identity and a production-function that defines the level of potential output in the long run are integrated with a conventional demand-oriented short-run Keynesian model. The objective function specified is quadratic and penalizes the squared deviations of its arguments from their desired values. The optimal control experiments consist of minimizing the objective function subject to the constraints of the macro model. Two approaches are used. The first consists of varying the relative structure of the weights over time by changing the rate of time preference in the objective function. The second approach aims at measuring and comparing the costs implied by different time horizons used by policy makers. In both cases, tradeoff relationships are derived between the performance of the economy in the short run and the long run, expressed in terms of the weighted squared deviations in the objective function. The major conclusions drawn from this study are that a short-run/long-run tradeoff does exist within the given structure of the economy. In addition, this tradeoff implies that as more emphasis is placed on the near-term, the higher will be the cost incurred in the longer term relative to the gain in the near-term, and vice versa. Other conclusions relate to the existence of inflation-unemployment and inflation-balance-of-payments tradeoffs, and the assignment of particular instruments to particular targets.

abstract: Doctor of Philosophy (PhD)


title: Immunomodulatory Studies of Dietary Consumption of Halogenated Aromatic Hydrocarbon Contaminated Great Lakes Coho Salmon (Oncorhynchus Kisutch)

contributor:
Sonstegard, R.A.
Biology

subject: Biology Biology

abstract: Diets containing coho salmon from the Pacific Ocean and Lakes Erie, Michigan and Ontario were fed to C57B1/6 and DBA/2 mice, Fischer CD rats and rainbow trout. Gas chromatographic analysis revealed a gradient of halogenated aromatic hydrocarbons (HAHs) in tissues of coho salmon from Lakes Erie, Michigan and Ontario and bioaccumulated levels in livers of C57B1/6 and DBA/2 mice. The toxicity parameters of hepatomegally, mixed function oxidase enzyme induction and hypothyroidism in mice correlated with elevated HAH concentrations in dietary salmon. Following consumption of coho salmon from Lake Ontario, plaque forming cell responses were reduced in C57B1/6 mice and increased in rats, whereas cell mediated immune responses remained relatively unaffected in rodents. Regulatory T--Iymphocyte subset numbers in mice were not altered by dietary exposure to HAH contaminated coho salmon. Humoral immune responses, natural killer cell activity and host resistance in rainbow trout were not altered following dietary exposure to Great Lakes coho salmon or HAHs.

abstract: Doctor of Philosophy (PhD)


title: Release and Actions of Prostaglandin E₂ From Canine Airway Epithelium

contributor:
Daniel, E.E.
Medical Sciences

subject:
Medical Sciences
Medical Sciences

abstract: Asthma is a condition of the airway characterized by 1) a reversible increase in airway resistance; 2) airway hyperresponsiveness; and 3) airway inflammation (Juniper et al., 1981; O'Byrne, 1986; Boushey and Fahy, 1995). Defects of the airway epithelium have been suggested to play a role in the pathogenesis of asthma (Goldie et al., 1986; Knight et al., 1994), and loss of the epithelium is associated with increased reactivity of the underlying smooth muscle (Jongejen et al., 1991; Candenas et al., 1992). It has been proposed that the airway epithelium releases one or more factors which inhibit smooth muscle contraction, termed the epithelial derived inhibitory factor (Tschirhart et al., 1987; Fernandes et al., 1989; Ullman et al., 1991). The inhibitory prostaglandin PGE₂ has been demonstrated to be released from the epithelium (Barrel and Bigby, 1995) and to modulate airway smooth muscle contraction (Braunstein et al., 1988; Abela and Daniel, 1995). In patients with asthma, inhalation of an allergen may result in a biphasic response consisting of an early asthmatic response and a late asthmatic response (Dolovich et al., 1989; Sterk et al., 1993). The late asthmatic response is an indirect measure of allergen-induced airway inflammation (Dolovich et al., 1989; Sterk et al., 1993) and an animal model of the late asthmatic response is produced by inhalation of the allergen Ascaris suum by dogs (Sasaki et al., 1987). in the studies presented in this thesis, the release and actions of PGE₂ from canine airway epithelium, both under unstimulated conditions and following inhalation of the Ascaris suum antigen, were examined. Tracheal and bronchial tissues were excised and studied in the organ bath where contractile responses to agonists and electrical field stimulation, as well as PGE₂ release were measured. Finally, a potential mechanism by which PGE₂ may effect smooth muscle relaxation was examined. In unstimulated animals, PGE₂ was released from tracheal epithelium and inhibited smooth muscle contraction. This release of PGE₂ was dependent upon electrical field stimulation, and was not blocked by the addition of neurotoxins. In the antigen model, tracheal PGE₂ release was increased from animals that inhaled antigen but did not develop late airway hyperresponsiveness comapred to animals that inhaled vehicle or inhaled allergen and did develop a late response. The release of PGE₂ was not dependent on field stimulation. Demonstration of in vitro hyperresponsiveness of the tracheal smooth muscle was dependent on removal of the epithelium. Bronchial smooth muscle from the antigen model did not demonstrate in vitro hyperresponsiveness, even when hyperresponsiveness was observed in vivo. There was an increase in the basal release of PGE₂ from the bronchi of animals that were hyperresponsive in vivo. PGE₂ increases intracellular cAMP concentrations (Madison et al., 1989; Coleman et al., 1994). Our investigations in tracheal smooth muscle demonstrated that cAMP does not lower intracellular Ca²⁺ and cause relaxation of airway smooth muscle by stimulation of the sarcoplasmic reticulum Ca²⁺ pump. The results indicate that PGE₂ was released from airway epithelium and modulated smooth muscle contraction. Alterations in the release of PGE₂ were demonstrated in an animal model of asthma, as PGE₂ played a protective role in the development of airway hyperresponsiveness. Modulation of PGE₂ may be a possible therapy for the treatment of asthma and prevention of the late asthmatic response.

abstract: Doctor of Philosophy (PhD)


title: Identification of Linear Multivariable Continuous-Time Systems

contributor:
Sinha, Naresh K.
Electrical Engineering

subject:
Electrical and Electronics
Electrical and Electronics

abstract: The problem of identification of linear multivariable continuous-time systems from input-output data is considered. A survey has been made to present the direct and the indirect approaches in identifying continuous-time systems from the samples of the observations. The direct approach with approximate integration seems to be more promising and hence it is adopted in this work. Three direct methods based on the use of block pulse functions, trapezoidal pulse functions and cubic splines have been compared and applied for multivariable systems. A comprehensive study has been conducted to analyze the effect of noise on the identification. The analysis was carried out first for the single-input single-output case and then extended to the multivariable case. A new approach is presented to overcome the combined effect of the errors in the approximation/and additive white noise on the identification of continuous-time systems. The method consists of modelling the combined error term. Extensive simulations are conducted in order to illustrate the merits of the new procedure. The problem of order determination has been considered and three order determination tests have been studied and applied for continuous-time systems, two of them for the first time as far as the author is aware. The problem of the selection of the structure that will give good conditioned parameterization is also considered. A new procedure to identify the structure in the input-output form is presented. This procedure is suitable for both stationary and non-stationary systems when a change in the structure occurs while the order remains constant. It uses the concept of overlapping parameterization to choose a better conditioned parameterization for the multivariable system whenever ill conditioning is detected. A switching criterion is presented based on the complexity principle which provides a good monitor of the conditioning of the parameterization as well as the suitability of the tested structure.

abstract: Doctor of Philosophy (PhD)


title: Capillary GC/MS Analysis of the Volatile Flavor Components in Wines

contributor:
Tomlinson, R.H.
Chemistry

subject: Chemistry Chemistry

abstract:
A new analytical method has been developed for examining flavor compounds in wine that detracts from the traditional method; the isolation-concentration process takes 5½ hours, using only 95 ml of wine. The heart of this method is a new design of a low-temperature, high-vacuum concentrator, which is more efficient than any previously described design of its kind. It was used together with a previously designed solvent extractor to isolate and enrich the volatile fraction of the wine. Capillary GC/MS techniques were used to separate and identify components of the flavor extract.

The method was used to confirm the presence of 2-methoxy-3-isobutylpyrazine, a twice compound previously identified in the grapes but not in the wine, for the first time in Cabernet Sauvignon wine. Ethyl 4-acetyloxybutyrate and 2-hydroxybenzothiazole were also identified for the first time in this wine.

This method was used to analyse the volatile flavor composition of White Riesling, whose vines have recently been successfully cultivated locally. The results of the qualitative and quantitative analyses of the musts and wines of local White Riesling compared quite favorably with results obtained on the same grape variety cultivated in the temperate climate. These results, it is hoped, would enable vintners and viticulturalists anticipate the potentialities of the locally cuItivated vinifera vines.

It was discovered that the method used to examine the flavor composition of vinifera varieties had to be modified for the labrusca varieties and, only under inert conditions could the compound tentatively identified as N-(N-methyl,N-hydroxy-ϒ-aminobutyryl)glycine be detected in all the varieties examined. For the first time, it is being suggested that this compound, rather than methyl anthranilate, may be responsible for the typical labrusca flavor. 3-Methyltetrahydrothiophene, 3-methylthiopropanol, phthalide, 2,5-dimethyl-4-hydroxy-3(2H) furanone, dihydrobenzofuran, 2-hydroxybenzothiazole and α-naphthol were identified for the first time in Moulin Rouge and Concord.

abstract: Doctor of Philosophy (PhD)


title: Variation and Evolution in Proteins of the Drosophila Male Reproductive Tract

contributor:
Singh, R.S.
Biology

subject: Biology Biology

abstract: Improved two-dimensional gel electrophoresis (2DE) and silver staining were applied to Drosophila male reproductive tract proteins. Genic variation was scored for about 300 polypeptides in 20 isofemale lines each of Drosophila melanogaster and D. simulans. Approximately 10% of loci were polymorphic within each species, with average heterozygosity in the range: 2-3%. These estimates are significantly lower (2-5 fold) than analogous ones from one-dimensional gel electrophoresis (1DB) of soluble enzymes in the same Drosophila populations. This confirms earlier reports of low variability in 2DE proteins from Drosophila, Homo and Mus. It is argued that the technical improvements applied, as well as other considerations, indicate that the variability differences are not artifacts of electrophoretic technique. 2DE was also used to compare male reproductive tract proteins between D. melanogaster and D. simulans, D. simulans and D. mauritiana, and D. simulans and D. sechellia. About 10% of loci were apparently fixed for different alleles between D. melanogaster and D. simulans. About 25% of polypeptides within D. melanogaster or D. simulans lacked a detectably homologous spot in D. simulans or D. melanogaster, respectively. Many of these unpaired spots may represent large (>10-fold) changes in polypeptide expression. Male reproductive tract proteins may be evolving faster than other proteins in these four species, as judged by 2DE comparisons of imaginal disc proteins and 2DE proteins of whole-body extracts. Finally, polypeptides localized to glandular tissues of the male reproductive tract in D. simulans were on average more highly polymorphic than polypeptides expressed in both testis and glandular tissues or only in testes. Glandular polypeptides of D. simulans were also more highly diverged from those of the other three species, compared to polypeptides expressed in testes. These increases occurred along with decreases for polypeptides co-expressed in testes and glands. These patterns were weaker in D. melanogaster. The results are discussed with reference to theories of balanced genetic structure in populations, and shifts in such balance during species formation.

abstract: Doctor of Philosophy (PhD)


title: Application of Technology Insertion to Particle Accelerator Modernization and Operations Support

contributor:
Poehlman, W.F.S.
Electrical Engineering

subject:
Electrical and Computer Engineering
Electrical and Computer Engineering

abstract: This thesis discusses a design methodology that can be employed as a framework for the design of computer-centered performance enhancement systems for technology insertion into non-computerized human-machine systems. This methodology seeks to hybridize and explout the benefits of several diverse areas of electrical and computer engineering, specifically knowledge-based reasoning, fuzzy logic-based control, real-time system design, human-machine interaction, computer-human interface, and software engineering. The methodology for combining these disciplines is used in the realization of a specific application: The Particle Accelerator Control Expert System (PACES), an artificial intelligence-based performance enhancement and control system for a KN-3000 Van de Graaff particle accelerator. PACES combines knowledge-based reasoning and human factors concept to furnish accelerator operators with a computer-centered operations support facility. Knowledge-based reasoning is coupled with real-time systems concepts to provide the capability for autonomous accelerator control. Technology insertion, human-machine interaction and human-computer interface concepts are used to design a simple, safe, flexible and low-cost operations support system that is accepted by both veteran and novice operators alike.

abstract: Doctor of Philosophy (PhD)


title: Community and aerial photograph analyses of salt marsh vegetation within the southern Gulf of St. Lawrence

contributor:
Howarth, P.J.
Geography

subject: Geography Geography

abstract:
A classification of salt marsh communities for barrier environments within the southern Gulf of St. Lawrence is presented. Communities are described in terms of their species composition, frequency and cover, phenology, and habitat requirements. An idealized marsh profile outlining typical marsh communities, species frequencies and tide relations is constructed from surveyed transect and vegetation data. Its applicability to other sites within the study area is evaluated through aerial photo interpretation.

The tide is identified as one of the controlling factors in community distribution or zonation across the marsh profile. Indicator communities, whose occurrence is indicative of specific tide levels are identified for mean sea level, mean high water and higher high water levels.

Photo communities are compared to floristic communities. An evaluation of aerial photo interpretation for marsh community identification and delineation is carried out. The optimal film type, scale and season combination for maximum community discrimination is determined.

Interpretation of marsh communities from aerial photographs is extended through space and time. Community-environment relationships and responses, identified from present data are shown to be consistent.

With the detailed background knowledge provided by the floristic analysis, the aeiral photo interpretation of marsh communities was enhanced.

abstract: Master of Science (MS)


title: The Dynamics of Promise: Narrative Logic in the Abraham Story

contributor:
Cooper, Alan
Religious Studies

subject: Religion Religion

abstract:
The Abraham narrative (Gen 11:27-25:11) has long been approaches history, or as a source for history, whether of actual events, or of Israelite literature, religion, and theology. With the development of the modern principles of historical enquiry, biblical scholars felt the need to examine critically the historical veracity of the biblical text. Critics noted many textual features, which, from such a perspective, they interpreted as indications that the text was not a single, continuous account, but an assemblage of numerous earlier traditions. For the sake of historical honesty, and in search of historical knowledge, higher critics turned their attention to identifying and isolating these various sources.

Since the early 1960s, the historico-critical perspective has gradually been yielding to a literary-critical view of the Bible which is far more sympathetic to the integrity of the received text. From the new perspective, and in the light of recent developments in literary theory, it is possible to discern the equivocal character of the evidence higher critics advance in support of their hypotheses. The same data which seem so compelling for higher-critical reading also serve the radically different ends of a holistic literary-critical approach. The fact that the text (like any text) has a history is never denied, but it is irrelevant to the new approach.

This thesis offers a description of the plot of the Abraham narrative, accompanied by a detailed analysis of the first half of the narrative (11:27-17:27). The thesis concentrates on those features of the narrative which are crucial for understanding the text's structure, for example, key-word., repetition, anticipation, and defeated expectation, to mention but a few. The methodology employed is rooted in close reading, but with special attention to recent reader-response criticism (e.g. M. Perry, W. Iser, and U. Eco). Such an approach concentrates on the Iiterary details and techniques of the narrative, and on the way in which they guide the reader's actualisation of the text. It is argued that the kind of description undertaken here is the prerequisite for evaluation of the text as literature, history, or theology.

abstract: Doctor of Philosophy (PhD)


title: An Experimental and Theoretical Study of Fluidelastic Instability in Cross Flow Multi-Span Exchanger Tube Arrays

contributor:
Weaver, D. S.
Mechanical Engineering

abstract: An experimental study was conducted to investigate fluidelastic instability in multi-span heat exchanger tube arrays. This work is in support of nuclear steam generator design, especially with regard to the U-bend and inlet regions, where tubes are subjected to non-uniform cross flow. The design guidelines defined in the current ASME codes and other recommended semi-emphirical formulas for fluidelastic instability have been based on the extension of experimental results from single span tube bundles. In this study, a specially designed multi-span tube array test rig was used to investigate the effects of partial flow admission. Using this test rig, the water flow can pass across any location along the tube span. Various end supports were used in the different experimental set-ups. Therefore, not only the first mode but also the higher vibration modes can be excited, depending on the location of the flow and tube-support configurations. It has been found that vibration modes higher than the third mode do not have significant vibration displacement. The experiments show that the fluid energy is additive along the span, regardless of the tube mode shape. Response peaks were observed prior to the ultimate fluidelastic instability. By analyzing the corresponding Strouhal numbers, it was found that both vortex shedding and secondary instability mechanisms exist. These two different phenomena may interact and enhance each other. Therefore, high amplitude displacement can be reached even before the ultimate fluidelastic instability. The previous and present experimental data suggest that the energy fraction is a representative parameter in the analysis of the flow induced vibration caused by nonuniform flow velocity distribution. However, existing design guidelines do not always give conservative predictions for the critical velocity. This research reveals that a single correlation of reduced velocity versus mass damping ratio does not follow the same trend in air and liquid flows. An improved design guideline is suggested, which gives consistent conservative flow velocity predictions in multi-span tube arrays. In parallel, an analytical model was developed for the prediction of fluidelastic instability in cross flow multi-span heat exchanger tube arrays. The model is based on concepts developed by Lever and Weaver, as well as Yetisir and Weaver, but is extended to include some crucial factors. Velocity and pressure fluctuations, caused by tube vibration were obtained by using continuity and momentum equations in curvilinear coordinates. Rather than the nonlinear function previously used, a linear area perturbation decay function was introduced to account for the decay of disturbances away from an oscillating tube. Thus, an analytical solution could be obtained. The resulting explicit instability expression is a more convenient tool to analyze effects of various design parameters. The difference between the linear and nonlinear decay functions was found to have a negligible effect on the stability threshold. Critical velocity in both streamwise and transverse directions was calculated, and the latter is lower in the high mass damping ratio range. Therefore, only the instability in the transverse direction needs to be analyzed in that range. On the other hand, there is no clear trend in the low mass damping ratio range, which agrees with many previous research results. This model is a multiple flexible tube model. Tubes directly two rows upstream and downstream of a central tube, neglected in the Yetisir and Weaver model, but are included in the present model. Significant improvement is obtained for the parallel triangular tube arrays. In contrast, little improvement is achieved on the other tube patterns due to the reduced influence of the upstream tube wake. The velocity distribution and mode shape along the tube span were introduced into the model. This is made possible because of the explicit instability equation. Therefore, the present model, in which fluid flow in two-dimensional, but considering tube mode shape in the third dimension, can be used to calculate the fluidelastic instability for multi-span tube arays. The comparison between the theory and experimental data agrees well.

abstract: Doctor of Philosophy (PhD)


title: UV Enhanced Mutagenesis of Adenovirus in Human Fibroblasts

subject: Biology Biology

abstract:
UV-induced cellular "error-prone" repair was examined by the comparative determination of the enhanced reactivation (UVER) and mutagenesis (UVEM) among viral progeny resulting from singIe cycle lytic infections of intact or UV-irradiated Ad5ts36 and Ad5ts125 in unirradiated or UV-irradiated confluent human fibroblasts. The induction of phenotypic wild type revertants among the viral progeny was determined by plaquing at 33°C (permissive) and 39°C (nonpermissive) on HaLa or KB indicator monoIayers. UV-irradiation of Ad5ts36 and Ad5ts125 resulted in a dose dependent increase in the UV-Induced reversion frequency (RF) of viral progeny and a dose dependent exponential decrease in progeny survival in unirradiated normal fibroblasts. Kinetic analysis of UV-induced reversion suggests that 2.5 ± 0.3 (Ad5ts36) and 2.4 ± 0.5 (Ad5ts125) "hits" were required to produce a targeted reversion event among the viral progeny derived from normal human fibrolasts. The expression of UVER and UVEM was examined as a function of Increasing time delay between cellular UV-irradiation and viral infection for various time periods. UV-irradiation of normal human fibroblasts (10 J/m/2), carried out 24 hours prior to viral infection, resulted in an increased RF for both unirradiated (untargeted increase) or UV-irradiated (targeted increase) virus. A maximal UVEM of 1.4 ± 0.2 was observed concomitantly with the maximal UVER (3.4 ± 0.8) and targeted increase (1.9 ± 0.3) when viral infection was delayed 24 hours following cellular UV-irradiation.

The maximal untargeted increase (2.0 ± 0.5) was observed when viral infection was immediately following cellular irradiation and declined as viral infections were delayed for longer time intervals. Different time courses for the targeted and untargeted increases suggested that these processes may be separateIy reguIated in human fibroblast cells.

DNA repair-deficient human fibroblast strains from patients with ataxia telanglectasia (AT), xeroderma plgmentosum (XP) and Cockyane's syndrome (CS) were also examined for the expression of UVER and/or UVEM of UV-irradiated adenovirus. AT fibroblasts expressed a significantly reduced UVEM (0.31 ± 0.12) of UV-irradiated adenovirus as compared to normals when viral infections were delayed 24 hours following celluIar UV-irradiation. A fibroblasts also displayed abnormally reduced UVER of UV-irradiated adenovirus when viral infections immediately followed cellular UV-irradiation. Aberrant expression of both UVER and UVEM of UV-irradiated adenovirus in AT suggests that these cells may be deficient in an error-prone DNA repair process or express enhanced error-free repair. Similarity, the XP variant strain studied displayed some aberration of UVEM when compared to normals indicated by a reduced UVEM (0.52 ± 0.2) of UV-irradiated adenovirus for viral infections delayed 24 hours after cellular irradiation. UV-induced reversion of adenovirus progeny derived from unirradiated XP 25RO (complementation group A) was hypermutable on a per unit dose basis but when corrected for survival, reversion was similar to that seen for normals. This suggests excision repair is an error-free process. UVER and UVEM of UV-irradiated adenovirus in CS fibroblasts (a non cancer prone condition) were similar to that observed in normals when viral infections were 24 hours after cellular irradiation. These results suggest that fibroblasts from cancer-prone individuals (AT, XPA, XP var) all express abnormal parameters of UV-induced mutagenesis. The underIying mechanism(s) responsible for this abnormal mutagenesis may ultimately contribute to the cancer-prone nature of these syndromes.

abstract: Doctor of Philosophy (PhD)


title: Atomic hydrogen-assisted epitaxy for the reduction of composition modulation in InGaAsP

contributor:
Thompson, D. A.
Engineering Physics

subject:
Engineering Physics
Engineering Physics

abstract: A miscibility gap exists in the InGaAsP/InP system of heterostructures such that a lateral composition modulation (LCM) occurs on the surface during growth resulting in the production of InAs-rich and GaP-rich regions within the layer. As a consequence, the important material properties relevant to optoelectronic device performance, such as the carrier mobility, luminescent properties and surface morphology, are less than optimum. Hence, this work investigates the influence of LCM on the structural and optical properties of InGaAsP quantum wells and thick layers grown by gas source molecular beam epitaxy on (100) InP substrates. Two novel growth techniques, argon plasma-assisted epitaxy and atomic hydrogen-assisted epitaxy, are developed to reduce the LCM. The reduction in LCM obtained with plasma-assisted epitaxy is explained in terms of the presence of atomic hydrogen within the argon plasma stream. A detailed atomistic model, including surface reconstruction effects based on reflection high energy electron diffraction observations, is developed to describe the surface-mediated processes that occur during growth in the presence of atomic hydrogen. A simple rate equation is used to understand the reduced LCM in terms of a decreased surface diffusion length of adatoms.

abstract: Doctor of Philosophy (PhD)


title: Geochemical Studies of Archean Iron Formations and Association Volcanic Rocks (Kirkland Lake and Temagami/Ont. areas)

contributor:
Schwarcz, H.P.
Crocket, J.H.
Geology

subject: Geology Geology

abstract:
The Boston Iron Range forms part of a steeply folded Archean supracrustal volcano - sedimentary assemblage in the Abitibi Greenstone Belt. Horizons of Algoman type oxide facies iron formation and enclosing volcanics in the Adams Mine area are situated in the thermal aureole of the post - Kenoran Lebel Syenite Stock; recrystallized mineral assemblages of Upper Greenschist/Lower Amphibolite facies are superimposed upon prehnite - pumpellyite facies terrain. Stratigraphically, the composite sequence represents the transition between two volcanic Supergroups in the Kirkland Lake area, each comprised of a threefold magmatic succession of komatiitic - tholeiitic - calc - alkalic affinity. Lenses of distal, calc - alkalic Skead Group pyroclastics, terminating the Lower Supergroup, and volcaniclastic sediments are intercalated in a series of Larder Lake Group submarine volcanics of magnesian - tholeiitic magma affiliation, extruded from fissure systems in an extensional tectonic regime, and comprising the basal stratigraphic unit of the Upper Supergroup.

Magmatic cyclicity present among Supergroups is observed also on a smaller scale within members of the Larder Lake Group. Four major, repetitive volcanic cycles are recognized in the Adams Mine area, three of which are terminated by laterally persistent horizons of BlF. Each cycle is comprised of a characteristic sequence of lithologies of either a high-magnesian (komatiitic)-, low-magnesian- or tholeiitic series.

Petrogenetically, the Larder Lake Group magma series evolved from a peridotitic mantle source through various degrees of partial melting and fractional crystallization. REE signatures and concentrations of incompatible elements indicate that the differentiation of the diverse magma suites took place at different crystal levels.

Chemical sediments associated with the volcanic sequence are found either as thin, discontinuous interflow units, marking a brief cessation of magmatic activity, or as thick, laterally persistent horizons of banded iron formation, each deposited during a major hiacus of extrusive volcanism. Both types of chemical precipitates show a close spacial association to volcaniclastic material of calc - alkalic magma affinity, and a lithologic control for the deposition of chemical sediments in a semi-restricted basin is implied. Local variation of BIF components (oxide facies BIF or minor sulfide iron formation) is attributed to the presence or absence of organic productivity in a deep water environment.

Oxygen isotope studies of BIF components, and comparison of the Adams Mine medium grade metamorphic terrain to the lower grade environment of the Sherman Nine near Temagami reveals, that iron formation is very susceptible to large scale communication of fluids, and that homogenization is complete at temperatures of 350-400 °C. However, higher temperatures (T>450 °C) are required for a complete isotopic re-equilibration between phases in adjoining BIF mesobands. Here, temperatures derived from quartz-magnetite fractionations coincide with thermal stabilities of metamorphic mineral assemblages.

Although the spatial distribution of Algoman type BIF is indicative of a volcanogenic hydrothermal source, oxide facies iron formations formed distal to centers of exhalative activity. Volcanic emanations mixed with seawater prior to the precipitation of ferro-silicic components in local, semi-restricted basins. While a structural control assumes major importance in the concentration of base - and precious metals in BIF horizons, the potential for a syngenetic accumulation of such metals during the degassing of the volcanic pile in interfIow chemical sediments is considerable.

abstract: Doctor of Philosophy (PhD)


title: Crystallographic studies on two structures of a kanamycin kinase: a Mg-AMPPNP and a Mg-ADP complex.

contributor:
C., Daniel S.
Biochemistry

subject: Biochemistry Biochemistry

abstract: 3',5"-aminoglycoside phosphotransferase type IIIa (APH(3')-IIIa) belongs to a family of bacterial enzymes that phosphorylate the aminoglycoside antibiotics. The modified antibiotics are rendered ineffective due to a lowered affinity for their targets in the bacterial cells. APH(3')-IIIa phosphorylates regiospecifically the 3'-and/or the 5" - hydroxyl groups of nine aminoglycosides. To gain insight into the chemical mechanisms involved in phosphate transfer, the crystal structures of APH(3')-IIIa complexed with a Mg-ATP analog and Mg-ADP have been determined to 2.4 Ȧ and 2.2 Ȧ resolution, respectively. These complexes represent the first and the last step in the enzyme kinetic reaction pathway and their structures are almost identical. Half of the protein molecule shows striking structural resemblance to the catalytic cores of protein kinases, which share less than 6% amino acid sequence identity with APH(3')-IIIa. The folding of this structurally conserved region forms the nucleotide-binding pocket in which five of the seven invariant residues form an elaborate phosphate recognition network via two Mg²⁺ ions. In the Mg-AMPPNP complex, the coordination spheres surrounding the two Mg²⁺ ions are far from the preferred octahedral geometry, which is observed in the Mg-ADP complex. The geometry of the Mg²⁺ ion that binds to the carboxylate oxygens of an invariant Asp is particularly distorted. This Mg²⁺ ion may play a role in triggering or controlling the phosphoryl transfer reaction. This hypothesis would likely have extended implications in understanding the details of the catalytic mechanisms of protein kinases. A potential antibiotic-binding site on APH(3')-IIIa is also immediately obvious. A cluster of residues conserved among the APH(3') isozymes line a partially solvent exposed pocket that displays a net electronegative surface potential. This binding pocket satisfies the requirements for binding to a broad spectrum of cationic aminoglycoside substrates.

abstract: Doctor of Philosophy (PhD)


title: Lactate and Proton Dynamics Following Strenuous Exercise in Rainbow Trout (Salmo gairdneri) and Flathead Sole (Hippoglossoidas elassodon)

contributor:
Wood, C.M.
Biology

subject: Biology Biology

abstract:
Strenuous exercise in both rainbow trout (Salmo gairdneri) and flathead sole (Hippoglossoides elassodon) caused substantial blood acidosis of combined respiratory (protons due to CO2 accumulation) and metabolic (protons due to metabolic acid accumulation) origin. The contribution of the respiratory component was maximal immediately following the cessation of exercise and was fully corrected within 1 h. The metabolic acid load in the blood reached a maximum at 0.5 - 1 h after exercise and required 8 - 12 h to recover fully.

Although lactic acid production by glycolysis generates stoichiometrically equivalent amounts of lactate and protons in muscle during exercise, their blood concentrations during recovery were quite different. Recovery in rainbow trout displayed a pattern in which lactate accumulated in the blood in excess of metabolic protons. The flathead sole exhibited the exactly opposite discrepancy where proton accumulation in the blood exceeded that of lactate. L(+)-lactic acid infusion experiments in both fish illustrated that preferential removal of either protons or lactate from the blood could not account for the observed lactate/proton discrepancies.

Experimentation using an isolated, perfused rainbow trout trunk showed that the myotome can differentially release lactate and protons into the extracellular space in response to the appropriate extracellular signals. Through the manipulation of extracellular pH and PCO2 it was possible to regulate the rate of proton efflux from the myotome. This and other evidence indicates that a differential release of protons and lactate from the muscle causes the observed discrepancies during in vivo recovery.

Simultaneous muscle and blood sampling in vivo suggests that most (≈90%) of the lactate and protons produced during exercise are retained within the myotome. This causes a water shift into the intracellular space which contracts the extracellular space, resulting in haemoconcentration and disturbance in plasma ion balance. The eventual fate of the lactate and proton load retained within the muscle would seem to be metabolic removal in situ, probably glyconeogenesis or oxidation.

A model is presented which can explain the complex events occurring during recovery from strenuous exercise. This model integrates the results from in vivo and in vitro experimentation and hypothesizes on the mechanism and control of lactate and proton utilization within the muscle cell and their movements between body compartments.

abstract: Master of Science (MS)


title: Continuity of Care for Complex Health Populations: Effectiveness and Efficiency of Two Models of Hospital to Home Transfer

contributor:
Browne, Gina B.
Nursing

subject: Nursing Nursing

abstract: Objectives: To evaluate the effectiveness and efficiency of a model of transition from hospital to home compared to optimal usual care for individuals with congestive heart failure (CHF), selected as an exemplar of a complex health population. Intervention: Strategic alliance or partnership between hospital and community health care sectors focused on the transition phase to 2 weeks post hospital discharge. Implementation of an evidence-based protocol for supportive care activities are enhanced linkages with the providers and patients. Study Questions: 1: Does Transitional Care, as an example of an inter-agency service alliance, improve the health related quality of life outcomes (MLHFQ & SF-36) for individuals with CHF more than optimal usual care? 2: What were the comparative expenditures for health services utilization at 6 weeks post hospital discharge with Transitional Care versus optimal usual care for the CHF population from a societal point of view (Browne et at., Health Services Utilization Inventory)? 3: Was there a subgroup of individuals with CHF recently discharged from hospital for whom one of the approaches to care was more effective and less expensive? DESIGN: Randomized control trial with baseline (pre hospital discharge), 2 and 6 week post discharge follow-up and outcome assessment. SAMPLE & SETTING: 123 individuals with heart failure admitted to two nursing units at a tertiary university affiliated teaching hospital. (60 experimental, 63 control) RESULTS: Clinically and statistically significant improvements in emotional well-being was associated with Transitional Care with no greater expense from a societal point of view. However, there was an important difference in the types of resources used by each approach with greater use of institutionally based resources in the usual care group and more community based resources accessed by Transitional Care participants. No statistical interactions or characteristics of subgroups of participants could be identified who were better served by one approach or the other. Implications: All types of heart failure patients can benefit in measurable emotional gains in health with Transitional Care. Transitional Care is effective and the gains in outcome were achieved at no additional expense to society as a whole.

abstract: Doctor of Philosophy (PhD)


title: Neurocontrol of Robotic Manipulators

contributor:
Sinha, Naresh K.
Elbestawi, M.A.
Electrical Engineering

abstract: The thesis is devoted to investigating neurocontrol of nonlinear systems with uncertain and unknown dynamic models. The aim of my research in the neural network area is to search for fast learning algorithm with reduced computation burden. Novel theoretical synthesis and analysis of neurocontrol systems have been conducted and applied to control a robotic manipulator. Modified back propagation learning algorithm making use of the changeable shape of the nonlinear function of node is introduced. The resulting algorithm results in a better accuracy and faster convergence. Neural network based control scheme is used to control the motion of a manipulator. The neural network plays the role of an approximate inverse model of a robot and are then used in conjunction with a conventional proportional plus derivative (PD) controller. To demonstrate the feasibility of the proposed algorithm and neurocontrol scheme, intensive computer simulations were conducted. Different types of adaptive tracking problems and regulation problems are considered. The proposed scheme possesses robustness to systems model uncertainty and changing conditions of operations. Simulation results are quite promising. It is concluded that neural networks, by virtue of their natural ability to learn from data, are well suited for dynamic reconstruction, bringing the world of nonlinear dynamics closer to practical use. To demonstrate the practicability of the proposed scheme, experiments were conducted on an existing two-link manipulator and a single link manipulator. Results confirm the practicability of the proposed scheme. The thesis concludes that the neurocontrol approach is capable of learning the tasks of reasonable complexity and it should be possible to train a system for a variety of operations using a neural network of practical size.

abstract: Doctor of Philosophy (PhD)


title: Characterization of Human Adenovirus type 5 Early Region 1 Proteins Using Anti-peptide Antibodies

contributor:
Branton, Philip E.
Medical Sciences

subject:
Medical Sciences
Medical Sciences

abstract:
Human adenoviruses are known to transform rodent cells in culture and these cells are tumorgenic when injected into new born animals. It has been well established that the early region 1 (El) of human adenovirus type 5 is necessary and sufficient for oncogenic transformation. The El region is comprised of two transcription units known as E1A (0 to 4.5% of the genome) and E1B (4.5 to 11.2%), each of which produces multiple species of mRNAs and polypeptides. E1A is also required to activate the transcription of other viral early regions. In the present study anti-peptide sera were used to identify and characterize these viral proteins.

Anti-peptide sera specific for the amino- and carboxy-termini of E1A were raised and these two sera precipitated an identical set of four major polypeptides of 52, 50, 48.5, and 45K and two minor species of 37.5 and 35K. Studies using E1A mutant viruses also revealed that 52, 48.5, and 37.5K polypeptides are derived from the 1.1 kb mRNA, and the 50, 45, and 35K species from the 0.9 kb mRNA of E1A. These sera were also used to identify polypeptides that are associated with E1 proteins. A set of five cellular polypeptides consisting of >250K, 105K (doublet), 68K, and 65K species were found to co-precipitate with E1A proteins under various conditions and the nature of this association was investigated using the anti-peptide sera as well as an E1A-specific monoclonal activity.

Antisera against synthetic peptides corresponding to the both termini of E1B 58K were also raised and used to identfy 58K from wild-type and mutant-infected cells. It had previously been shown that protein kinase activity was associated with 58K. To ask if protein kinase activity was intrinsic to this viral protein several conventional methods were used to purify 58K and the results suggested that such activity may be intrinsic to this viral protein.

The anti-peptide sera were used to purify El proteins. A simple purification procedure using these sera and their corresponding synthetic peptides was developed and highly purified 58K and E1A proteins were obtained. Attempts were made to study protein kinase activity using these purified El proteins, however, the results were inconclusive and it was not possible to unequivocally determine if kinase activity was intrinsic to them.

abstract: Doctor of Philosophy (PhD)


title: Influence of Binocular Deprivation on the Development of Attention

contributor:
Maurer, Daphne
Psychology

subject: Psychology Psychology

abstract: I examined the influence of binocular deprivation on the development of visual spatial attention in humans. I began by testing normals, in order to work out procedures appropriate for monocular tests of patients (aged 8 to 20 years) who had been treated for bilateral congenital cataracts during infancy. There were two reaction time tasks (Eriksen 1995; Posner, Nissen, & Ogden, 1978): 1. Detection-Participants pushed a button as soon as they detected a target that was presented in a cued, miscued, or noncued peripheral location and that appeared 100, 400, or 800 msec (SOAs) after a central cuel; 2. Discrimination with Distractors-Participants indicated which of two shapes appeared in the periphery 400 msec after a central cue, with those shapes surrounded by compatible or incompatible distractors. On task 1, I compared 32 eyes of 16 patients (mean duration of deprivation = 5.1 mosl range = 1.8 - 19.5 mos) to three groups of normals (8, 10 years, adult, N= 24 per grp). Covert orienting was adult-like by 8 years of age. Patients performed normally when the cue appeared 100 or 400 msec before the target. Patients with more than 4 months of deprivation, unlike normals and patients with shorter deprivation, responded no more quickly on trials with valud cues than on those with valid cues 800 mec before the target. On task 2, I compared 30 eyes of 15 patients (mean duration of deprivation = 4.5 mos; range = 1.8 - 7.6 mos) to 15 age-matched controls, and 24 normal 10-year-olds to 24 adults. On invalid trials, patients were slowed more than age-matched controls by incompatible distractors. As on Task 1 at a 400 msec SOA, patients showed a normal validity effect in the lower visual field. In the upper visual field, there was a larger-than-normal validity effect. As in Task 1, normal 10-year-olds were adult-like in the ability to shift attention covertly; however, they were slowed more than adults by incompatible distractors. Together these findings indicate that the normal development of attention is sensitive to experience early in life: Deprivation disrupts aspects of the attentional system that are involved in shifting and maintaining attention. The results also add to the evidence that deprivation especially disrupts abilities that are immature at birth and that develop slowly during childhood (Maurer et al., 1989). These studies on the normal development of attention showed that while cover orienting is developed by 8 years of age, at least under some conditions, the ability to ignore distracting information is not yet fully developed even by 10 years of age. This result suggests that the parietal system, involved in the ability to shift attention covertly in adults, and the frontal system, involved in the ability to ignore distractors, develop at different rates.

abstract: Doctor of Philosophy (PhD)


title: Influence of Dynamic Behaviour of Materials

contributor:
Subramanian, S.V.
Materials Engineering

subject:
Materials Science and Engineering
Materials Science and Engineering

abstract: The influence of dynamic behaviour of materials (i.e. the response of materials to large strain, high strain rate, deformation under large hydrostatic pressure occurring during metal cutting) on machinability (i.e., chip morphology, tool wear and surface finish) has been investigated in ferrous alloys with a wide range of matrix and volume fraction of second phase particles. With the increase of cutting speed, there is change in the tribological phenomenon at the tool-chip interface from sliding to seizure. A physical model for seizure is proposed based on atomic contact at the tool-chip interface. The model predicts the critical cutting speed for onset of seizure from force measurements. Seizure is said to occur when the normal stress exceeds yield strength of asperities such that the true area of contact approaches the apparent area of contact. The tribological phenomenon of seizure is shown to cause thermoplastic shear localisation. In consequences, the temperature at the tool-chip interface rises, leading to dissolution wear of the tool into the chip by a diffusion mechanism which causes chemical wear of the tool. The technique of ICP-MS has been developed and used to separate the physical and chemical wear aspects of the tool by measurement of minute concentrations of tungsten present in the chips as WC as distinct from tungsten atomically dissolved in the chips. The results have confirmed that chemical crater wear dominates at high cutting speeds. The temperature distribution at the tool-chip interface has been predicted by finite element analysis and used to compute diffusion wear. A comparison of theoretical and experimental values of diffusion wear suggests that high diffusivity paths operate at the tool-chip interface to enhance the diffusivity by more than two orders of magnitude. The maximum depth of the measured crater depth profile has been found to coincide with the phase transformation temperature of the workpiece material rather than the maximum predicted temperature at the tool-chip interface. The amount of dissolution wear, as measured by the amount of tungsten transferred into the chips is attributed to dislocation pipe diffusion. It is further suggested that dislocations generated by deformation concomitant with phase transformation provide high diffusivity paths that contribute to enhanced diffusion wear. The implication is that dissolution crater wear of the tool is phase transformation coupled. Dissolution crater wear can be suppressed if the tribological phenomenon of seizure can be prevented. This can be achieved by in-situ lubrication at the tool-chip interface through inclusion engineering of the workpiece. Alternatively, the diffusion wear can be minimized by coating the tool with a compound which hasa the least solubility in the workpiece. The microstructural response to changes of metal cutting variables during the machining of a range of iron alloys with varying heat treatment condition and microstructural constituents of the matrix has been investigated to establish the inter-relationship among chip morphology, tool wear and surface finish. The microstructural changes in the chips have been analysed by optical microscopy, scanning electron microscopy, transmission electron microscopy and x-ray diffractiion techniques. The results from the chips formed during machining of martenistic Fe-28.9%Ni-0.1%C alloy confirmed the presence of austenite, exhibiting grains as fine as 40-100 nm in the white shear bands. This structure is attributed to a sequence of events: the reverse phase transformation of martensite to austenite, shear localisation, formation of the transformation shear bands, and probably dynamic recrystallisation. This it is demonstrated that thermal softening due to phase transformation causes shear localisation leading to chip segmentation in the primary shear zone. Phenomenological observations are presented to confirm that shear localisation is caused by (i) geometrical softening due to second phase particles (graphite inclusions in cast iron, inclusions in free cutting steels), (ii) thermal softening of the matrix due to phase transformation or recrystallisation and (iii) a combination of the above. Shear localisation causes step temperature rise in a narrow band, referred to as shear band. The interaction of the priary shear band with cutting edge of the tool is found to cause dissolution wear of the cutting edge of the tool. The loss of the cutting edge in turn is shown to impair surface finish. The effect of metal cutting variables, i.e., speed, feed, depth of cut, external lubricants on shear localisation, chip morphology and tool wear is investigated. It is shown that chip segmentation can be suppressed by decreasing the feed. This is analyzed in terms of damage concepts underlying chip fracture behaviour.

abstract: Doctor of Philosophy (PhD)


title: Generation of Cell-mediated Immune Responses to Pichinde Virus in Mice

contributor:
Rosenthal, K.L.
Medical Sciences

subject:
Medical Sciences
Medical Sciences

abstract:
These studies were undertaken to characterize cytotoxic cell responses to Pichinde virus (PV; a member of the arenavirus family) in various strains of inbred mice. Emphasis was placed on examining the relationship between cells with natural killer (NK) activity and H-2 restricted, virus-specific cytotoxic T lymphocytes (CTL) that are detected in the spleens of inbred mice after infection with PV.

Primary i.v. inoculation of mice with PV resulted in augmented spleen NK activity that peaked at 3- 4 days after infection. This NK response was followed by an H-2 restricted, virus-specific CTL response that peaked 3 days later. Rechallenge of PV-primed mice with homologous virus resulted in a slight but significant increase in spleen NK activity 1 day after reinfection, and this was followed 3 days later by peak CTL activity. Thus, memory cell-mediated immune responses appeared more rapidly after secondary in vivo challenge with PV. Furthermore, the temporal kinetic relationship between virus-induced NK and CTL responses was maintained after both primary and secondary infection with PV, which suggested that virus-induced NK cells may represent pre-CTL.

To investigate the relationship between these two cytotoxic cell populations, expression of lineage specific cell-surface antigens on virus-induced NK and CTL effectors was examined. NK cells induced after primary and secondary infection with PV were found to rapidly acquire the pan-T cell marker Thy-1, which was expressed on mature anti-viral CTL. In addition, asialo-GM 1 (a glycolipid which has been considered a marker of NK cells) appears to be expressed on PV-specific CTLp; treatment of PV-primed spleen cells with a polyclonal rabbit antiserum to this marker plus complement prior to secondary in vitro restimulation with PV-infected macrophages prevented the generation of secondary CTL responses to PV. Furthermore, multiple i.v. injections of this antiserum were able to abrogate the in vivo generation of both NK and CTL responses after primary or secondary infection with PV.

Secondary NK and CTL responses were generated in mice that had been pretreated with cyclophosphamide (CY), suggesting that memory cell-mediated immune responses can be reactivated in vivo without undergoing cell division. In contrast, treatment with CY before primary infection delayed the appearance of virus-induced NK activity and abrogated the generation of H-2 restricted, virus-specific CTL. Rechallenge of these CY-treated, NK-primed mice resulted in the rapid generation of a secondary NK response that was not followed by either a primary or secondary CTL response. This long-term block in CTL generation was not due to the establishment of a persistent PV infection. Memory CTL generation could be restored by secondarily coinfecting mice with PV and a second arenavirus such as Tacaribe virus (TV) or lymphocytic choriomeningitis virus (LCMV), or by injection of interleukin 2 (IL 2)-containing supernatants after rechallenge with PV. To demonstrate that IL 2 was the responsible lymphokine in these supernatants, highly purified IL 2 was added to in vitro cultures of spleen cells from CY-treated, PV-primed mice. In the presence of PV-infected syngeneic macrophages, addition of purified IL 2 resulted in a dose dependent restoration of H-2 restricted, anti-PV CTL activity. In addition, the CTL precursor frequency of CY-treated, PV-primed mice appeared to be markedly reduced compared to that in normal PV-primed mice. Thus, the long-lasting block in the ability to generate PV-specific memory CTL appears to be due to both a lack of helper T cell activity a significant reduction in the number of CTLp. Furthermore, these results suggest that priming the NK compartment is sufficient to prime for a memory CTL response, provided helper factors such as IL 2 are supplied.

abstract: Doctor of Philosophy (PhD)


title: The Relationship Between Lymphocyte Responsiveness to Lymphokines and Susceptibility to Viral Infection in Syrian Hamsters

contributor:
Rawls, William E.
Medical Sciences

subject:
Medical Sciences
Medical Sciences

abstract:
Two inbred strains of Syrian hamster have been shown to display genetically determined differences in resistance to infections with the arenavirus, Pichinde virus (PV). After intraperitoneal injection, the virus grows to higher titres in the spleens of the susceptible strain, MHA, than in the spleens of the resistant strain, LSH. Preliminary studies examining the basis of susceptibility demonstrated that resistance or susceptibility to the virus did not lie in an inherent difference in target cells to become infected, but suggested that there was a quantitative difference in target cells between the two strains of hamster. The following experiments were conducted in attempts to verify the hypothesis that MHA hamsters are susceptible to infection with Pichinde virus because they possess larger numbers of a splenic lymphocyte that serves as a target cell for virus replication and that also functions as an effector cell of nonspecific cytotoxicity.

The spleens and thymi of the high NK strain were found to display greater cellularity than those of the low NK strain. Additionally, thymocytes from MHA hamsters were found to proliferate to a greater extent than those of LSH hamsters in response to ConA-induced conditioned medium or purified interleukin 2 plus mitogen. As well, splenocytes from MHA hamsters showed high levels of lymphokine-activated killer cell (LAK) activity after culture in conditioned medium or interleukin 2. In both the thymus and the spleen, this difference in responsiveness was due to increased numbers of precursor cells responding to lymphokines in MHA organs. When lymphokine production was assessed, it was found that cells from the the high responder, MHA, synthesized less interleukin 2 than cells from LSH hamsters. Interleukin 1 production was equal in the two strains. These results led to the hypothesis that the susceptible hamsters contain immature lymphocytes, possibly because of the reduced interleukin 2 production. Increased numbers of relatively immature cells could account for the increased cellularity of lymphoid organs in these animals, and in the spleen, these cells may be responsible for increased NK activity, increased numbers of LAK precursors, and serve as target cells for PV replication.

Splenic cytotoxic cells in the hamster were characterized. Endogenous NK cells, virus-induced NK cells and LAK were all plastic nonadherent cells, as were the precursors for LAK. All populations expressed an antigen homologous to the murine Thy 1.2. Endogenous NK cells and virus-induced NK cells were similar in the expression of an asialo GMl homologue; both were reduced by 50% by treatment with this antiserum plus complement. LAK precursors and LAK effectors were negative for this marker, suggesting that LAK arise from the asialo GM1 negative component of endogenous NK activity. Treatment of hamsters with anti-asialo GM1 serum also reduced splenic NK activity in normal and virus-infected hamsters by 50%.

Cells infected with virus were characterized using the same criteria. A preferential infection of nonadherent cells was not evident before day 3 of infection, although MHA spleens already contained twice as much virus as LSH spleens. Both asialo GM1 negative and positive cells were infected. Culture of infected splenocytes in interleukin 2 induced high LAK, but failed to select out a population enriched for infectious centres compared to culture in medium alone, where no cytotoxic activity was evident. However, susceptible MHA hamsters with reduced NK activity after treatment with anti-asialo GM1 serum did display less virus at day 1 after infection with PV, but by day 3, virus loads were at control levels. Treatment with anti-asialo GM1 serum had no effect on the mortality of either strain of hamster. Treatment with purified interleukin 2 slowed mortality of MHA hamsters, although it did not do so by reducing viral replication. In total, t~ese data indicate that cells expressing an antigen detected by anti-asialo GMl serum that mediate some ~K ~ctivity can serve as target cells for PV replication, but these cells alone are not responsible. for the susceptibility of MHA hamsters • • Cytotoxic activity and infected centres could be dissociated, also suggesting that the jnitial hypothesis was incorrect. It could be that some other cell is the relevant target, that MHA hamsters may b~ susceptible because of increased number~ of all splenocyt~s, or that some .factor other than the presence or absence of a target cell accounts for their susceptibility.

abstract: Doctor of Philosophy (PhD)


title: Effect of Food Restriction on Serum and Pineal Indoles

contributor:
Brown, G.M.
Medical Sciences

subject:
Medical Sciences
Medical Sciences

abstract:
Food restriction has profound effects on various endocrine axes and on amine metabolism. In the present study, the effect of reduced food availability on pineal and serum indole was determined in adult male Wistar rats. Under a lighting regimen of 14 h light and 10 h dark, 3 weeks of 50% food restriction led to a reduction in 24 h mean serum tryptophan and serum serotonin levels but an increase in serum melatonin levels. The duration of the night-time melatonin rise was increased secondary to an earlier rise of both pineal and serum melatonin. Such changes in circulating melatonin may account for the gonadal regression observed in underfed animals. This pineal-gonadal interaction was further investigated after animals were subjected to shortened photoperiod or after pinealectomy. Shortened photoperiod failed to influence either the serum melatonin profile or the undernutrition-related gonadal regression. Pinealectomy, however, was able to reverse though incompletely the gonadal regression in underfed animals. When the pineal responsiveness to beta-adrenergic stimulation was determined in food restricted animals, both the time course and the dose responses were altered. The changes in pineal and serum melatonin post-stimulation, however, were atypical of either a sub- or supersensitive pineal gland.

Based on the present study, food availability proves to be another factor that can influence pineal activity. Its effect on the pineal, however, depends on the duration of food restriction and the environmental light/dark cycle.

abstract: Doctor of Philosophy (PhD)


title: Sedimentology of the Moosebar Tongue and Bounding Strata, Lower Cretaceous Blairmore Group, South-Central Foothills, Alberta

contributor:
Walker, Roger G.
Geology

subject: Geology Geology

abstract:
This thesis provides detailed sedimentological descriptions and generalized interpretations of depositional environments within the Lower Cretaceous Blairmore Group of Alberta. In earliest Blairmore time (Hauterivian - Barremian ?), uplift to the west resulted in a period of extensive pedimentation and deposition of coarse clastics of the Cadomin Formation. Paleogeographic reconstructions indicate that a series of humid-climate alluvial fans to the west fed a NW flowing trunk stream to the east that occupied the Spirit River Channel. In the Spirit River Channel, a series of lenticular channels filled with conglomerate and coarse-grained sandstone suggest that deposition was in pebbly braided and low sinuosity sandy fluvial environments.

Subsequent to deposition of the Cadomin Formation (Aptian time), finer grained sandstones and shales of the Gladstone Formation were deposited. Thicker sandstones commonly contain lateral accretion surfaces and are rooted in their uppermost parts indicating deposition in a high sinuosity meandering fluvial environment. Paleocurrent data suggest that the ancient rivers flowed NNW, debouching into a boreal sea to the north. The uppermost part of the Gladstone Formation contains nonmarine to brackish fauna and is interpreted as having been deposited in a large brackish lake analagous to modern Lake Maracaibo of Venezuela.

In early Albian time, a boreal sea (Clearwater Sea) transgressed southward and covered most of the central Alberta and northeastern British Columbia. Marine sandstones and shales of the Moosebar Tongue were deposited at this time. In the study area, the shoreline of the Clearwater Sea was oriented ENE-WSW and coarsening-upward sequences within the Moosebar Tongue indicate that the shoreline advanced by the progradation of nearshore bars. Deposition was in a high energy, storm-dominated system. Bordering the Clearwater Sea to the south was the large brackish lake in which sediments of the uppermost part of the Gladstone Formation were deposited.

Following regression of the boreal sea from the Foothills region in early to middle Albian time, a coastal plain environment prevailed within the depositional basin. As regression continued, the coastal plain sequence was overlain by a fluvial sequence deposited by large-scale meandering rivers. Paleocurrent data indicate that the rivers flowed generally northwards, subparallel to the foreland basin, and debouched into an Arctic embayment.

abstract: Master of Science (MS)