Open Access. Powered by Scholars. Published by Universities.®

Digital Commons Network

Open Access. Powered by Scholars. Published by Universities.®

Articles 1 - 24 of 24

Full-Text Articles in Entire DC Network

N-Aralkylated Derivatives Of 1-Aminobenzotriazole: Isozyme-Selective Mechanism-Based Inhibitors Of Guinea Pig Cytochrome P-450, Kimberley Janine Woodcroft Jan 1993

N-Aralkylated Derivatives Of 1-Aminobenzotriazole: Isozyme-Selective Mechanism-Based Inhibitors Of Guinea Pig Cytochrome P-450, Kimberley Janine Woodcroft

Digitized Theses

1-Aminobenzotriazole (ABT) and its N-benzyl (BBT), N-{dollar}\alpha{dollar}-methylbenzyl ({dollar}\alpha{dollar}MB), and N-{dollar}\alpha{dollar}-ethylbenzyl ({dollar}\alpha{dollar}EB) derivatives were compared for their potency and isozyme-selectivity for mechanism-based inactivation of guinea pig hepatic and pulmonary cytochrome P450 (P450) in vitro, through the use of isozyme selective substrates for the guinea pig orthologs of rabbit P450 2B4, 1A1, and 4B1 (P450 2Bx, 1A1, 4Bx, respectively). {dollar}\alpha{dollar}MB, {dollar}\alpha{dollar}EB, and to a lesser extent, BBT, selectively inactivated P450 2Bx in pulmonary microsomes from untreated or {dollar}\beta{dollar}-naphthoflavone ({dollar}\beta{dollar}NF)-induced, and hepatic microsomes from phenobarbital (PB)-induced, guinea pigs. P450 loss caused by ABT paralleled the inhibition of enzyme activity in hepatic and pulmonary …


Dynamics Of Morbidity And Mortality In Africa And Implications For Health Care Planning, Sulaiman Maladoh Bah Jan 1993

Dynamics Of Morbidity And Mortality In Africa And Implications For Health Care Planning, Sulaiman Maladoh Bah

Digitized Theses

The dissertation aims to tie together the empirical, theoretical and policy oriented aspects dealing with the dynamics of morbidity and mortality in Africa. On the theoretical aspect, scholars are arguing that the epidemiologic transition theory which provided the framework for understanding African mortality in the past, is actually part of a broader health transition theory which also includes a health care transition. In this theory, the overemphasis on biomedical interventions is down-played. To understand African mortality, it is argued, we have to consider the social and cultural determinants. Also we have to consider morbidity and its relationship to mortality. This …


Can A Local Government Ensure That Development Within Its Conurbation Area Is Financially Beneficial To Its Ratepayer?, Gabriel P. Dekel Jan 1993

Can A Local Government Ensure That Development Within Its Conurbation Area Is Financially Beneficial To Its Ratepayer?, Gabriel P. Dekel

Digitized Theses

The purpose of this thesis is to show that unchecked local development policies do not necessarily secure financial benefits to the local ratepayer and that they can pose a threat to the long-term well-being of communities. Yet local policy-makers are often unaware of this or unwilling to accept it. The theoretical review tries to explain the divorce between policy analysis and political behaviour. It shows how local government is constrained by political structures and processes which often result in an indiscriminate and costly approach to development policies as well as a deficient practice of fiscal impact analysis. An empirical study …


Drugs In Sport, The Straight Dope: A Philosophical Analysis Of The Justification For Banning Performance-Enhancing Substances And Practices In The Olympic Games, Angela Jo-Anne Schneider Jan 1993

Drugs In Sport, The Straight Dope: A Philosophical Analysis Of The Justification For Banning Performance-Enhancing Substances And Practices In The Olympic Games, Angela Jo-Anne Schneider

Digitized Theses

Many believe that "doping" has no place in sport, especially no place in the Olympic Games. Yet despite, or indeed perhaps because of, this belief remarkably little has been done in the way of attempting to justify those bans.;The arguments that are offered in support of bans fall into four categories: (i) that doping is cheating or unfair, (ii) that it is harmful, (iii) that it perverts the nature of sport, and (iv) that is is dehumanizing or unnatural.;I examine each of these categories of argument in turn. The cheating or unfairness argument is readily dismissed as question-begging. The substances …


The Consequences Of Low Birthweight, Ann L. Robson Jan 1993

The Consequences Of Low Birthweight, Ann L. Robson

Digitized Theses

An extensive literature investigating the consequences of low birthweight for childhood development has focused on group differences and the prediction of global cognitive outcomes. The purpose of this thesis was to identify factors that predict specific childhood outcomes and to consider explanatory models of the role of early medical risk for childhood language, motor and attention outcomes. Ninety low birthweight children participating in a prospective longitudinal study were assessed at {dollar}5{lcub}1\over2{rcub}{dollar} years of age. Although there were no consistent differences between within-sample medical risk subgroups on the childhood outcome measures, regression analyses demonstrated that both early medical risk and environmental …


Host And Viral Determinants Influencing The Pathogenesis Of Coronavirus-Induced Neurological Disease In Rodents, John M. Pasick Jan 1993

Host And Viral Determinants Influencing The Pathogenesis Of Coronavirus-Induced Neurological Disease In Rodents, John M. Pasick

Digitized Theses

Host and viral determinants influencing the outcome of coronavirus JHM infections of the CNS of rodents were investigated using intact animals and primary neural cell cultures. Two problems pertinent to the process of pathogenesis were addressed. The first was concerned with elucidating host factors responsible for controlling the age dependent nature for induction of the demyelinating form of disease in suckling rats. In the second, the basis of the relative resistance exhibited by inbred SJL/J mice to JHMV was examined in relation to both host and viral determinants.;Using primary, dissociated neural cultures from perinatal rats, several interesting aspects of host …


Multiple Fluxes Influencing Amazonian River Chemistry, Kurt O. Konhauser Jan 1993

Multiple Fluxes Influencing Amazonian River Chemistry, Kurt O. Konhauser

Digitized Theses

The rivers flowing through the Amazon Basin are both physically and chemically heterogeneous. Through detailed geochemical analyses, this study indicates that variability is primarily controlled by substrate lithology in the source region and the erosional regime. Observations suggest that it is possible to classify the chemical composition of Amazonian rivers according to the geochemistry of the soils in their catchment regions and vice versa.;The ability of microorganisms to undergo chemical exchanges with their aqueous environment, involving both the uptake and excretion of various elements, has been overlooked as an important factor in determining the chemistry of Amazonian rivers. Silicon extracted …


The Molecular Characterization Of Human Monoclonal Antiplatelet Autoantibodies, Gregory Andrew Denomme Jan 1993

The Molecular Characterization Of Human Monoclonal Antiplatelet Autoantibodies, Gregory Andrew Denomme

Digitized Theses

Autoimmune thrombocytopenia occurs in a number of clinical settings including idiopathic or autoimmune thrombocytopenic purpura (ITP), systemic lupus erythematosus (SLE), and the lupus anticoagulant (LAC) syndrome. The etiology of the disease, the scope of the autoantigens targeted, and the epitopes involved in autoimmune thrombocytopenia are largely unknown. ITP has the hallmark of the presence of 'pathogenic' autoantibodies targeting platelet glycoproteins (GP) IIb/IIIa and GP Ib/IX. Associated with the thrombocytopenia in the LAC syndrome is the presence of anti-phospholipid antibodies (approximately 95% of cases). The detection of autoantibodies to a variety of self antigens in non-autoimmune individuals prompted this study to …


Suppression Of Eae In The Lewis Rat By Treatment With Neuroantigen-Containing Liposomes, Colleen Sheila Stein Jan 1993

Suppression Of Eae In The Lewis Rat By Treatment With Neuroantigen-Containing Liposomes, Colleen Sheila Stein

Digitized Theses

Treatment of Lewis rats with intracardiac injections of neuroantigen-containing liposomes significantly reduced the clinical severity of spinal cord-induced experimental allergic/autoimmune encephalomyelitis (EAE). Liposomes containing myelin basic protein (MBP), galactocerebroside (GC), or MBP + GC were effective in this respect, while liposomes containing proteolipid protein were not. The best protection was afforded by liposomes composed of whole myelin, as these ameliorated both the acute and relapsing phases of the disease, with a concomitant reduction in CNS pathology.;Neuroantigen-specific proliferative responses of lymphnode cells (LNC) taken from liposome-treated rats were markedly attenuated in comparison to control LNC, while delayed type hypersensitivity (DTH) reactions …


Executive Support System Impact Viewed From A Learning Perspective, Betty Mary Vandenbosch Jan 1993

Executive Support System Impact Viewed From A Learning Perspective, Betty Mary Vandenbosch

Digitized Theses

Although learning has been associated with information technology, a theory of how technology, learning and organizational performance are related has never been developed. This dissertation employs a cognitive learning perspective to investigate the impact that executive support systems (ESS) have on organizations by proposing and testing a model of the relationships among these constructs.;The model describes the process by which ESS lead to learning and increased organizational performance. It proposes two types of learning: mental model maintenance in which new information fits into existing mental models and confirms them; and mental model building in which mental models are changed to …


The Myth Of Cartesian Rationalism: An Examination Of Experience In Le Grand, Desgabets, And Regis, Patricia Ann Easton Jan 1993

The Myth Of Cartesian Rationalism: An Examination Of Experience In Le Grand, Desgabets, And Regis, Patricia Ann Easton

Digitized Theses

Recent re-evaluation of the question of the exact role of experience in the Cartesian philosophy has emerged from many quarters. The metaphysical issue of innate ideas has been raised by such scholars as McRae and Miles, and a close examination of the role of empirical enquiry and methodology in Cartesian science have been undertaken by Clarke, Garber, Buchdahl and Laudan, to mention only a few. These recent reappraisals of the role of experience in Descartes's philosophy have been cast mostly in twentieth-century terms with a specific view to concerns of the present.;My research centres on an examination of the philosophical …


Occupational Exposure To Styrene: Contribution To Hearing Loss, Andrea M. Sass-Kortsak Jan 1993

Occupational Exposure To Styrene: Contribution To Hearing Loss, Andrea M. Sass-Kortsak

Digitized Theses

Prolonged significant noise exposures are well known to result in permanent hearing loss. However, little is known of the contribution of industrial chemical exposures to hearing loss. Information available, both from animal and human studies, raises the possibility that certain aromatic hydrocarbons are ototoxic. The purpose of this study was to assess whether occupational styrene exposure causes hearing loss in a group of workers in the fibre reinforced plastics manufacturing industry. The hearing acuity of 299 subjects was determined, using pure tone screening audiometry, at the beginning of a single workshift and again at the end of the shift. On …


A Reassessment Of Locke's Theory Of Cognition Of The External World, Thomas Heyd Jan 1993

A Reassessment Of Locke's Theory Of Cognition Of The External World, Thomas Heyd

Digitized Theses

Locke's Essay concerning Human Understanding has generally been read as primarily concerned with epistemology. In particular, it has been claimed that the Essay attempts to defeat epistemological skepticism, but fails in this enterprise because of the veiling character of Locke's ideas. By way of reexamination of the texts in question I show that epistemological skepticism is not the topic of the Essay, and that there is not sufficient reason to claim that Locke's account of knowledge leads to epistemological skepticism. I argue, moreover, that the motivating topic of the Essay is moral skepticism, and I explain the central role of …


Comparative Studies Of The Effects Of Menogaril And Adriamycin On Cell Morphology And Membrane Function Of Parental And Multidrug Resistant Cells, Stewart E. Daly Jan 1993

Comparative Studies Of The Effects Of Menogaril And Adriamycin On Cell Morphology And Membrane Function Of Parental And Multidrug Resistant Cells, Stewart E. Daly

Digitized Theses

This project was initiated to obtain a better understanding of the cellular mode of action of the anthracycline drug menogaril. Comparative experiments demonstrated that menogaril was as cytotoxic as adriamycin against parental AUX B1 Chinese hamster ovary cells (CHO), however, multidrug resistant (MDR) CH{dollar}\sp{lcub}\rm R{rcub}{dollar}C5 CHO cells, which are characterized by the overexpression of P-glycoprotein relative to the parental cells, were less resistant to menogaril. When parental and MDR cells were exposed to equitoxic concentrations of both drugs, menogaril accumulated to a higher level, however, both drugs accumulated to a significantly higher level in the MDR cells. Immediately after exposure …


The Classification Of The Schizophrenias According To Symptomatology: A Two-Factor Model, Ian R. Nicholson Jan 1993

The Classification Of The Schizophrenias According To Symptomatology: A Two-Factor Model, Ian R. Nicholson

Digitized Theses

The purpose of this investigation was to examine a proposed two-factor model of schizophrenic symptomatology (Nicholson & Neufeld, in press). To achieve this aim, a semi-structured interview was administered to one hundred schizophrenic patients and a series of symptomatology scales were rated. Preliminary analysis indicated that these ratings were consistent with previous research in schizophrenia.;The item-level data from the scales was clustered to reduce redundancies in the large amount of data (95 schizophrenia variables) and 26 symptom clusters resulted. These symptom clusters were then rated and subsequently placed into four schizophrenia variable groups (paranoid, nonparanoid, positive, and negative). The four …


Isozyme-Selective, Lung-Selective Mechanism-Based Inhibitors Of Cytochrome P-450 And Determination Of P450 Isozyme Specificity For Arachidonic Acid Metabolism, Leah Christine Knickle Jan 1993

Isozyme-Selective, Lung-Selective Mechanism-Based Inhibitors Of Cytochrome P-450 And Determination Of P450 Isozyme Specificity For Arachidonic Acid Metabolism, Leah Christine Knickle

Digitized Theses

1-Aminobenzotriazole (ABT) and its N-benzyl (BBT) and N-{dollar}\alpha{dollar}-methylbenzyl ({dollar}\alpha{dollar}MB) derivatives were compared as isozyme-selective, lung-selective (vs liver) mechanism-based inhibitors of P450 in guinea pigs 4 hr following i.v. administration. Monooxygenase activities selective for guinea pig orthologues of rabbit P450 1A1, 2B4 and 4B1 (1A1, 2Bx and 4Bx, respectively) were determined in pulmonary and hepatic microsomes. BBT and {dollar}\alpha{dollar}MB inactivated pulmonary P450 in an isozyme-selective manner. In non-induced and phenobarbital-induced animals the order of inactivation was 2Bx {dollar}>{dollar} 1A1 {dollar}>>>>{dollar} 4Bx whereas in {dollar}\beta{dollar}-naphthoflavone-induced animals {dollar}\alpha{dollar}MB specifically inhibited 2Bx. BBT and {dollar}\alpha{dollar}MB were also highly selective for the inactivation …


Surface Modifications Of Silicon Induced By Low Energy Reactive Ion Bombardment, Wayne Harold Chang Jan 1993

Surface Modifications Of Silicon Induced By Low Energy Reactive Ion Bombardment, Wayne Harold Chang

Digitized Theses

The effects of low energy reactive ion bombardment of semiconducting silicon material have been investigated by X-ray photoelectron spectroscopy. The residual surface damage induced by a conventional fluorocarbon plasma reactive ion etching of silicon consisted of a uniform fluorocarbon deposited film approximately 4nm in thickness which covered a silicon compound reaction layer. This reaction layer was comprised of silicon oxides, carbide and fluorosilyl species distributed in depth to approximately 2nm. The removal of the residuel surface damage was accomplished by an ozone oxidation plus a wet oxide chemical etching step processing and monitored by surface charge spectroscopy. This residual surface …


Cardiorespiratory And Peripheral Adaptations After Cardiac Transplantation, Lizanne Marie Bussieres Jan 1993

Cardiorespiratory And Peripheral Adaptations After Cardiac Transplantation, Lizanne Marie Bussieres

Digitized Theses

The cardiovascular, pulmonary and musculoskeletal systems were investigated in seven studies of patients with end-stage heart failure before and/or after receiving a heart transplant. The purposes of the studies were to determine the time course and magnitude of the changes in peak oxygen uptake, cardiopulmonary response to exercise and peripheral skeletal muscle histology and biochemistry after cardiac transplantation. In addition, the physiological basis for the limited exercise capacity and the effect of exercise posture on cardiac performance and secretion of atrial natriuretic peptide was also evaluated in cardiac transplant patients.;In the first study, the peak oxygen uptake almost doubled from …


Fabrication Of Indium Phosphide Misfet, Raymund Wai-Man Kwok Jan 1993

Fabrication Of Indium Phosphide Misfet, Raymund Wai-Man Kwok

Digitized Theses

The presence of excessive energy states in the bandgap of III-V semiconductor surfaces is commonly found and has considerably hindered the development of III-V semiconductor technology. Although InP metal-insulator-semiconductor field effect transistors (MISFETs) are attractive switching and driving elements for the InP-based optoelectronic devices which have been widely used for communication applications, interface states of the dielectric/InP structure are known to cause surface Fermi level pinning and drain current drifting, a fact which causes the MISFETs to be unacceptable for any practical usage. In this study, we used a wide range of surface and interface analytical techniques to investigate a …


Characterization Of A Schistosoma Mansoni C(3) Receptor As A Potential Vaccine Candidate, Erika Eliana Silva Jan 1993

Characterization Of A Schistosoma Mansoni C(3) Receptor As A Potential Vaccine Candidate, Erika Eliana Silva

Digitized Theses

Schistosomiasis, a chronic and debilitating parasitic disease, infects an estimated 200 million people and causes 750,000 deaths a year. Therefore, the development of an effective vaccine is of high priority for the control of this disease.;The surface of the syncytial epithelium of Schistosoma mansoni consists of an apical plasma membrane and an overlying envelope. The rapid turnover of these membranes in response to the host's attack is considered to be one of the mechanisms by which this parasite escapes the effects of the host's immune system. Our approach has been to identify surface components which play a pivotal role in …


Visual Interactive Linear Programming: The Concept, An Example And An Empirical Assessment Of Its Value In Supporting Managerial Decision-Making, Arshad Ahmad Taseen Jan 1993

Visual Interactive Linear Programming: The Concept, An Example And An Empirical Assessment Of Its Value In Supporting Managerial Decision-Making, Arshad Ahmad Taseen

Digitized Theses

Decision support systems (DSS) and visual interactive (VI) modelling emerged during the 1970s at roughly the same time (Sprague and Watson, 1989), (Belton, 1991). Both ideas seem to have been driven more by advances in computer technology and increasing management demands than any theory. There are both similarities and differences between them. DSS often use some visual and interactive features (see Turban and Carlson, 1989), but seldom refer to them in terms of a VI model. On the other hand, a VI model is almost always built to support decision-making, and is often referred to as a DSS. Both have …


Contrast-Enhanced Ct Measurement Of Blood-Brain Permeability In Human Brain Tumors, Wai Tong Yeung Jan 1993

Contrast-Enhanced Ct Measurement Of Blood-Brain Permeability In Human Brain Tumors, Wai Tong Yeung

Digitized Theses

A contrast enhanced CT method was developed for measuring the blood-brain permeability (K) and cerebral plasma volume (V{dollar}\sb{lcub}\rm p{rcub}){dollar} in human brain tumors in-vivo. In patient studies, Isovue 300 (iopamidol) was injected intravenously at a dosage of 1 ml/kg patient body weight. It was followed by serial head scanning of the tumor and arterial blood sampling to measure the contrast concentration in tumor and arterial plasma respectively. The leakage of iopamidol into the brain through the blood-brain barrier was modelled as an exchange process between two compartments, namely, the intravascular plasma space and the tissue interstitial space. Using this compartmental …


Mobile Robot Perception In Unknown And Unstructured Dynamic Voxel Environments, Yuefeng Zhang Jan 1993

Mobile Robot Perception In Unknown And Unstructured Dynamic Voxel Environments, Yuefeng Zhang

Digitized Theses

The Occupancy Grid Method is a probabilistic spatial modelling technique. In this method, the space to be navigated is subdivided into a grid of cells. Associated with each cell is a probability that indicates the likelihood that that cell is occupied. This method was developed for handling a world where the robot was the only moving object. Thus, it lacks the ability to predict the location of moving objects over time.;In my thesis, an Extended Occupancy Grid Method is presented. The extension handles objects moving at constant velocity. In this method, a four-dimensional location-velocity space is subdivided into cells. Each …


A Characterization Of The Fast Pyrolysis Of Cellulose And Wood Biomass, Robert George Graham Jan 1993

A Characterization Of The Fast Pyrolysis Of Cellulose And Wood Biomass, Robert George Graham

Digitized Theses

The science of biomass fast pyrolysis is relatively young and incomplete. To date, there has been no systematic attempt to define fast pyrolysis in terms of chemistry, product distribution, kinetics, heat transfer requirements, and requisite process conditions. Neither has there been any experimental work which tracks the reaction progress as a function of both temperature and residence time. Furthermore, the literature provides a fragmented and often contradictory view of the nature of fast pyrolysis.;This thesis provides a coherent picture of the fast pyrolysis of cellulose and wood via an extensive literature review and systematic research. The literature review is an …