Digital Commons Network^™

Kant And The Conservation Of Matter, Joel Morris

Digitized Theses

This dissertation is an examination of Kant's rather notorious claim that natural science, or physics, has a priori principles, understood as the claim that physics is constrained by rules warranted by the essential nature of thought. The overall direction of this study is towards examining Kant's claim by close study of a particular principle of physics, the principle of the conservation of matter. If indeed this is a principle of physics, and Kant can successfully show that it is a priori, then it will be reasonable to conclude, in company with Kant, that physics has a priori principles.;Although Kant's proof …

Spectroscopic Studies Of Mercury And Cadmium Binding To The Protein Metallothionein, Wuhua Lu

Digitized Theses

Metallothioneins (MT) are a class of low molecular weight, cysteine rich proteins, which bind a wide range of metals both in vivo and in vitro. This protein has become the subject of intensive interest in many branches of the life sciences over the past two decades.;In this thesis, the manner in which mercury and cadmium bind to metallothionein has been studied using the techniques of circular dichroism (CD), magnetic circular dichroism (MCD), UV-visible absorption, and X-ray near edge absorption structure (XANES) spectroscopy.;At neutral pH, the Hg{dollar}\sb7{dollar}-MT and Hg{dollar}\sb4{dollar}-{dollar}\alpha{dollar} MT species formed from metal-free MT (apo-MT), or Zn-MT adopt a mercury-thiolate …

Immunoregulatory Cells And Mediators In Murine Bone Marrow, Douglas Chauncey Saffran

Digitized Theses

This thesis defines distinct immunoregulatory mechanisms which naturally exist in murine bone marrow (BM). Physical separation of BM cells revealed two immunoregulatory cell populations: a suppressor activity present in a fraction of large, low density BM cells predominantly of myeloid and blast cell morphology; and an enhancing activity contained in a fraction of small, high density BM cells enriched for lymphocytes. Both activities are associated with the production of soluble mediators which possess analogous function to the immunoregulatory cells.;The population of cells responsible for immune suppression have been referred to as Natural Suppressor (NS) cells. NS cells are unique in …

Prediction Of The Nerve Conduction Abnormalities Frequently Associated With Carpal Tunnel Syndrome From Clinical Features, M Gail Woodbury

Digitized Theses

This study was undertaken to develop a clinically useful model for predicting electrophysiological abnormality in the nerve conduction tests used in the diagnosis of carpal tunnel syndrome (CTS). The prediction model combined commonly recorded clinical history, signs, and symptoms in a multivariate analysis. Electrophysiological abnormality and adjustments for the influencing variables (sex, distance, and temperature) were based on normative nerve conduction values obtained in a control group (n = 104). This was the first study in this topic area in which prediction bands were used to adjust the criteria for assigning abnormality to account for influencing variables. The variables used …

An Immunobiological Study Of Natural Killer Cells, Marien J. Zanyk

Digitized Theses

The innate ability of the immune system to prevent the onset of cancer involves an intricate network of defense known as the natural killer (NK) cell system. As reactive elements in tumour defense and essential components of adoptive immunotherapy, NK cells represent a relatively new field of study that holds immeasurable potential in our struggle against cancer. Although their anti-tumour potential has been realized, NK cells and many of their regulatory processes, remain a scientific challenge. In order to exploit this system to its fullest potential, the functional mechanisms of NK-mediated tumour cell recognition and destruction must be fully understood …

An Application Of Case Relations To Document Retrieval, Xin Lu

Digitized Theses

The purpose of this research is to design a document retrieval model which is a structural model based on case relations and to test how effectively a prototype of this model would perform retrieval on a test database. Case relations are a major component of case grammar proposed by linguistic theorists and developed in computational linguistics and natural language processing.;The design of the structural retrieval model involves case relations and structured document representation, case relation-based natural language parsing and automatic structural indexing, and tree mapping and structural matching. In this model, a document is represented by a set of tree-like …

Generalized Design Of Damping Control, M. Sainath Moorty

Digitized Theses

This thesis establishes new guidelines to aid a system planning engineer in the process of improving the small signal stability of power systems. These guidelines help in designing controllers to increase the positive damping of poorly damped or unstable electromechanical modes of oscillations. Design strategies for damping controllers on generators (called power system stabilizers) and on Static Var Compensators (called supplementary controls) are described. The same procedure can be used for designing damping controllers on other dynamic devices like HVDC link, Flexible AC Transmission System (FACTS) elements etc.

In this thesis the particulars of the appropriate system representation and the …

Community, Consensus And Progress: Problems In Pragmatism From Peirce And Dewey To Putnam And Rorty, Paul Dickinson Forster

Digitized Theses

This thesis deals with an antinomy in debates among contemporary Pragmatists. Lodging the authority of rationality in the context of evolving traditions raises problems of relativism. Yet attempts to preserve the transcendence of reason raise epistemological problems Pragmatism was designed to circumvent. This thesis adjudicates disputes among contemporary Pragmatists, through a discussion of the historical origins of the issues that divide them.;Chapter I summarizes the structure of the argument. Chapter II describes the cultural context in which Pragmatism emerged. It is argued that even for Peirce, despite his emphasis on formal logic, Pragmatism cannot be understood apart from issues in …

Regulation Of Immune Responses To Self And Nonself, Angela Panoskaltsis

Digitized Theses

B cells are regulated early upon exposure to antigen by negative Fc signals generated by the crosslinking of antigen receptors with Fc receptors which is mediated by antigen-IgG-antibody complexes. This negative end-product feedback can be overcome by T helper cells, but in their absence, agents which bind to the Fc portion of IgG can replace the need for T cell help. Rheumatoid factor (RF) is a naturally occurring antibody with specificity for IgG-Fc and was investigated for its ability to block negative Fc signals. Monoclonal murine RF was shown to reconstitute, in an antigen-specific and dose-dependent fashion, both the primary …

Individual Differences In The Appraisal Of Stress And The Immunologic Consequences: Psychological Moderation Of Lymphocyte Activation And Cytokine Production, James Patrick Dobbin

Digitized Theses

A number of studies have adduced evidence suggesting that stressful events affect immunity in humans. The present research was designed to extend this earlier work by assessing cytokine production and blast transformation in mononuclear cells obtained from medical students writing an academic examination. Additionally, the hypothesis that personality characteristics can moderate the relationship between stress and immune functioning was investigated.;A number of response measures were assessed at each of 3 sample times: baseline (time 1); one month later, immediately after subjects had written an examination (time 2); and again 15 days later (time 3). The response measures included mood (subjective …

Factors Underlying The Use Of Information Sources In Government Institutions In Nigeria, Mutawakilu Adisa Tiamiyu

Digitized Theses

The study examined the relationships between the use of information sources by civil servants and the characteristics of their work, the organizational environments within which they seek information, and the characteristics of the information sources.;The study was based on a survey of senior civil servants in eleven ministries in seven states of Nigeria. In addition, library managers in eight of the ministries were interviewed and published documents about the ministries were analyzed.;Analyses revealed that civil servants use more information sources for complex work activities than for less complex activities. Also, direct relationships were observed between the use of certain external …

The T Cell-Mediated Response To A Syngeneic Tumour: Precytotoxic T Lymphocyte Frequency Measured By Limiting Dilution Assay, Robert Llewellyn Howell

Digitized Theses

The T cell-mediated response to a syngeneic tumour has been studied using the DBA{dollar}\\{dollar} 2-P815X mouse tumour model. If one hopes to intervene to change (improve) the immune response of a cancer patient to their tumour, it is necessary to understand the role(s) of the cells involved in that response.;The potential magnitude of a cytotoxic T lymphocyte (CTL) response depends, in part, upon the precursor or pCTL frequency. A limiting dilution assay (LDA) has been developed and used to measure the frequency of pCTL's in the animal both prior to tumour implantation and during the growth of the tumour. As …

Occupational Cancer Mortality In A Ten Percent Sample Of Males In The Canadian Labour Force, 1965-1979: The Establishment Of A Monitoring System, Joan Patricia Lindsay

Digitized Theses

This study involved the establishment of a system for monitoring occupational cancer mortality in a ten percent sample of males in the Canadian labour force. The system was designed to detect associations between occupations and industries, and specific cancer sites, which merit more detailed study.;Occupational histories of approximately a ten percent sample of the Canadian labour force from 1965 to 1971 were linked to the Canadian mortality data base maintained by Statistics Canada to determine the mortality experience of the cohort between 1965 and 1979, using computerized record linkage. Standardized mortality ratios (SMR) were calculated for each occupation and industry …

Public Knowledge': The Dissemination Of Scientific Literature In Victorian Canada As Illustrated From The Geological And Agricultural Sciences, Bertrum H. Macdonald

Digitized Theses

During the Victorian period when scientific work was established in Canada, Canadian researchers knew that access to the published literature was a crucial link to national and international scientific developments. This dissertation examines the effectiveness of the dissemination of scientific literature in Canada from the late 1830s to the end of the first decade of the twentieth century in two subject areas: geology and agriculture. It studies the careers of six scientists: Robert Bell, Elkanah Billings, Sir John William Dawson, James Fletcher, Sir William Edmond Logan, and William Saunders to learn what scientific literature was read and where it was …

The Application Of Informetrics To Information Retrieval Systems Design: A Simulation Study, Dietmar Wolfram

Digitized Theses

The efficient design and maintenance of information retrieval systems are still important considerations, even with the current availability of faster computer hardware and cheaper secondary storage. Informetrics, the quantitative study of information and its use, could provide the systems designer and analyst with tools with which to aid in decision making for optimising system performance.;This study examines how informetrics can be used to help the systems designer in deciding what types of file structures would provide the best performance for a given type of information system environment. It is hypothesized that for varying index term distributions and system term usage …

A Study Of Thermally Stratified Plumes In A Channel, Hani A. Farghaly

Digitized Theses

The problem of waste heat discharge into natural bodies of water is one of the environmental problems that has received considerable attention in recent years. The scope of most of the previous investigations has been limited to summer flow conditions and did not address the problem of waste heat discharge in cold climate regions. This thesis is concerned with the problem of a thermal discharge in a channel in the range of temperatures encountered in practice, including temperatures anticipated in cold climate regions.;More specifically, this study was conducted to: (i) develop numerical models of surface and bottom discharges in a …