This research is concerned with establishing a rationale which will link safe printmaking practices with artists' individual and sustainable creative practices, by investigating the preconception that printmaking practices may be limited by adopting such an environmentally sensitive approach. This has been investigated through a practice-led approach, which implicitly involves the researchers' professional practice as a visual artist printmaker. The cross disciplinary nature of this practice-led research has established that diverse and non-text based sources be included in the literature review. The resulting contextual review established the evolutionary nature of printmaking practices, the role played by individual artists perceptions of risk, and the limited ability of available literature to adequately link evolving and didactic creative practices to emergent boundaries established by environmental and occupational health and safety legislative criteria. There was evidently no theoretical framework for linking these apparently divergent criteria. The multi-disciplinary and practice-led context i. e. the research was generated by practice and carried out through practice, determined the range of methods employed: questionnaire, quantitative tests of materials; participation in, and initiation of collaborative case studies; documenting workshop practice and visual development of printed art works; and exhibition for peer review. These multiple methods and their complex interrelationships were visualised as a system of consequential actions, in order to externalise possible alternative actions and choices made by the researcher in response to this research. Analysis of these methods revealed that: the collaborative case studies and the researcher's own visual and practical response, established that a systematic revaluation of practice could link the idiosyncratic and individual creative practices to the use and selection of nonhazardous practices, which did respond to objective occupational health and safety rationale. This revealed the extent to which a systematic re-evaluation of 'established practices' may be synthesised into the working practice of the researcher and lead to the diversification of that practice - visually and practically. This process has resulted in the generation of a body of printed art works which implicitly embodied the hypothesis developed in this research; the development of a electronic database or 'morphological framework', which initiates a sequential examination of process at a structural level, collating, comparing and promoting previously un-considered alternatives based on a heterarchical model of risk. This process has offered tangible means of visualising the generative processes involved in making prints. The 'morphological framework' has implicitly linked the researcher's printmaking to a sustainable and environmentally sensitive creative practice, which is methodologically transparent and procedurally transferable.

This thesis describes a retrospective cohort study of cancer mortality among employees of the Celanese Canada Inc. synthetic textiles plant in Drummondville, Quebec. The study was commissioned by the company to confirm or refute a previous observation (Vobecky et al., Cancer 54:2537-2542, 1984) that there were higher mortality rates from colorectal cancer among male employees of the textiles unit, the cellulose acetate fiber manufacturing unit, and the cellulose triacetate and polypropylene extrusion units and to investigate whether mortality rates for other sites of cancer were associated with employment in each area of the plant and with occupational exposures. / Workers with more than one year experience at the plant were eligible for study if they were employed on January 1, 1947 or if they were newly hired between that date and December 31, 1977. Vital status as of December 31, 1986 was ascertained for 7,422 men and 2,720 women through a probabilistic record linkage to the Canadian Mortality Data Base. Among men, there were about 220,000 person-years of observation and 1,738 deaths and, among women, there were about 89,000 person-years of observation and 241 deaths. / Three reference regions were used to derive standardized mortality ratios (SMR): the entire Province of Quebec, semi-rural regions of the Province, and the area in which the plant is located. Results based on rates for these regions were generally similar. For men, the SMR for all causes of death was significantly less than unity (SMR = 0.71, 95%CI:0.68-0.74), as were the SMRs for most sites of cancer (SMR all neoplasms = 0.73, 95%CI:0.66-0.80). The SMR for colorectal cancer was 0.68 (95%CI:0.51-0.91). Of the 20 cancer sites examined in men, reticulum cell sarcoma was the only one having a significantly elevated SMR, and this occurred only among the subcohort of men hired prior to 1947 (SMR = 2.84, 95%CI:1.04-6.18, 6 deaths). For women, the SMR for all causes of death was 0.75 (95%CI:0.66-0.85) and there were moderately elevated SMRs for a number of sites of cancer, but none were significantly greater than expectation (SMR all neoplasms = 0.97, 95%CI:0.80-1.17). / SMRs were also calculated according to employment in each processing unit and exposure to occupational agents, and case-control analyses were carried out within the cohort for selected sites of cancer. Of the scores of associations tested, very few were significantly elevated. There were excesses of biliary cancers and non-Hodgkin's lymphomas among workers in the cellulose acetate fiber manufacturing unit. There were also significant associations between stomach cancer and exposure to cutting oils, and between prostate cancer and exposure to glycol monobutyl ether. However, none of these associations were persuasive. / With regards to colorectal cancer, there was a nonsignificant elevation in risk among workers who had ever worked in the polypropylene and cellulose triacetate extrusion unit (OR$ sb{ rm e}$ = 2.3, 95%CI:0.5-9.9) but there was no apparent increase in risk with increasing duration of employment. Thus, the evidence for an association was not convincing. For the cellulose acetate fiber manufacturing unit, the evidence of an increase, although based on few cases, was slightly more persuasive (OR$ sb{ rm e}$ = 1.9, 95%CI:1.0-3.6), but no trend was observed with duration. No association was observed with employment in the textiles unit (OR$ sb{ rm e}$ = 1.1, 95%CI:0.6-2.2) nor were there any noteworthy associations between colorectal cancer and any of the agents evaluated in the case-control analyses.

The prevalence of asthma and the role of occupational exposures was investigated in a cross-sectional study of 498 Montreal adults aged 20 to 44 years. Prevalences of asthma standardised for age and gender, using four definitions were: current wheeze: 23 8%, asthma symptoms and/or medicine: 12.9%, airway hyper-responsiveness: 15.1%, airway hyper-responsiveness and current wheeze: 7.0%. Imputation to adjust for non-response to airway challenge gave similar results. 56.9% of subjects reported occupational exposure ever to sensitisers and 10.8% to irritants. Current wheeze was associated with exposure to irritants (OR: 2.12 (1.03, 4.34)), and airway hyper-responsiveness with exposure to sensitisers (OR: 2.20 (1.10, 4.38)). Childhood asthma and atopy did not affect the associations. Population attributable risk was about 30% for airway hyper-responsiveness with exposure to sensitisers, and 5% for current wheeze with exposure to irritants. Studies with more precise exposure information may provide better evidence for the causality of the association.

The influence of psychological status on recovery from a first lifetime episode of acute low-back pain was assessed in compensated workers seen in a physiatry clinic. One hundred thirty-four participants of a back school intervention trial were selected and followed for 1 year. The objectives were to determine the evolution of psychological distress, well-being, pain, self-reported disability and spinal flexibility, and to determine the psychological factors associated with return to work and recurrence. Improvement occurred post-treatment in all measures except well-being which did not fluctuate over the year. Additional improvement in functional disability occurred at 6 and 12 months. Using multiple logistic regression, low baseline psychological distress predicted late return to work and high baseline well-being predicted recurrence. A second model for recurrence that was constructed with post-treatment scores on the longitudinal measures had greater predictive power than the model using baseline scores. These results have implications for the management of return to work.

The goal of this study was to verify if differences in respirable dust and respirable quartz concentrations exist with respect to the mines, the ore deposit types and the nature of workstations. / One hundred and seventy-nine respirable dust samples were collected in the six mines studied, in compliance with the method recommended by the Institut de recherche en sante et securite du travail du Quebec (IRSST). Then, samples were analysed using X ray powder diffraction technique to determine respirable quartz concentrations. / Results indicated statistically significant differences in the normalised exposure levels to respirable dust (p = 0.017), to respirable quartz (p < 0.001) as well as the quartz percentage in the respirable dust (p < 0.001) of the six mines studied. When grouped by ore deposit type, normalized exposure levels to respirable dust were not statistically different. However, statistically significant differences were noticed for normalized exposure levels to respirable quartz (p = 0.004) and respirable quartz percentage (p < 0.001) according to ore deposit types. / For all mines studied, respirable dust concentrations were all below the admissible exposure value whereas about 9% of the respirable quartz concentrations were equal or above the admissible exposure limit. Gold ore deposits hosted in quartz veins had the highest normalized respirable quartz exposure levels, as well as the highest percentage of quartz in the respirable dust when compared to gold ore deposits with sulfide lodes, the copper-zinc ore deposit and the disseminated gold ore deposit. / The study also revealed that workers who worked in the ore crushing and hoisting departments as well as loading and transport had higher normalised exposure levels to respirable quartz than workers who worked in the drilling and blasting or those who worked in the maintenance department. / In conclusion, this study stressed that quartz content in the mined rocks seems to be the most important factor influencing on respirable quartz concentrations in the mine worker's respiratory zone, but the relation between the two variables were not strongly correlated (Rs = 0.254, p = 0.005). Furthermore, the study showed that the gold ore deposits with quartz lodes had the highest normalized exposure levels to respirable quartz. Also, the workers assigned to ore crushing and hoisting departments as well as transport and loading had the highest exposure levels to respirable quartz. (Abstract shortened by UMI.)

Microcomputer technology and the provision of alternative data entry devices offers numerous opportunities for physically disabled individuals to integrate into work and school settings. For therapists specializing in adapted access one of the main challenges involves prescribing and customizing suitable input devices since objective procedures to facilitate this process are lacking. The two papers presented in this thesis aimed to respond to this limitation. In the first paper the adapted access process was viewed within the context of a human factors model. A critical review of the literature relating specific human factors criteria (e.g. digit loading) to ergonomic solutions (e.g. input/output efficiency) substantiated clinical approaches to adapted device prescription and customization. Two case studies were used to illustrate the application of this approach to physically disabled individuals. The second paper investigated therapists' abilities to judge the mechanical characteristics of switches. Objective data characterizing the activation force-displacement trajectories for eight commonly used adapted switches were collected and compared to clinicians' subjective evaluation of the same characteristics. The major finding was that although therapists' subjective estimates of activation force and displacement were reasonably good there were specific areas of weakness that should be rectified with quantitative, objective data. It is anticipated that these two papers will enhance the application of microcomputer usage for physically disabled individuals.

Nickel is frequently reported as an agent causing allergic contact dermatitis in humans and was selected as an example for the investigation into the molecular mechanisms of the sensitivity. Nickel, as a hapten, may not constitute the complete antigen. The protein of cellular conjugates of nickel formed in the skin may represent the antigenic complexes, but the number and nature are unknown. In this submission, allergic contact dermatitis to nickel is reviewed; data on the immunological processes from various human and animal-model systems relevant to this problem are appraised and experimental investigations into the antigenic complexes of nickel are described. The albino guinea-pig was selected as a suitable animal model and a test system was developed to induce and elicit allergic contact dermatitis to nickel in this species. Under the exposure conditions of this system, an incidence of the sensitivity of 70-100% in a test population was experimentally induced. This consistently high incidence was not achieved by the use of standard published animal methods. Time-coursed In vivo exposure studies, employing 63NiCl2 as a radiotracer, were performed to qualitatively and quantatively examine the absorption and accumulation of nickel in the skin. The results indicated that soluble nickel salts are poorly absorbed across the skin. Maximum plasma levels were seen after 12 hours of exposure, although these represented only a very small percentage of the appled nickel salts (0.06%). Absorbed nickel was excreted in the urine. Microautoradiography of in vivo exposed skin indicated that transappendageal passage may be the main route of entry into the body. Accumulation of nickel was apparent in the highly keratinized areas of the skin, and labelling of basal and supra-basal epidermal cells was observed. Dermal accumulation was not seen. Fractionation of the in vivo exposed epidermis by zonal ultracentrification and gel filtration revealed four main areas of nickel localization. It was found associated with a microsomal fraction, with albumin, with an epidermal protein fraction (molecular weight 8,700) and with low molecular weight (< 5,000) residues. The antigenicity of each isolated nickel-containing fraction was assessed by in vitro lymphocyte transformation. The primary antigens in this system were the epidermal protein fraction (molecular weight 8,700) and the microsomal fraction. The low molecular weight residues possessed some very weak antigenic properties. Allergic contact dermatitis appears to be a complex sensitivity reaction to more than one antigen in the skin. The recognition of antigen by the immune system is protein-carrier dependant and the processing of haptenic or antigenic information by microsomal constituents may be an importanat function in the induction phase of the dematitis.

Purpose. The objective of this thesis was to examine work in mines. Specifically, part #1 performed in-situ time/motion analyses of common mining jobs and part #2 analyzed in-situ energy expenditures while working in a mine. Methodology. Part #1- task and sub-task duration and subjective work intensity were investigated for thirty eight subjects from six different mining jobs. These jobs were then organized into 4 groups for statistical analysis based on precedence: Group 1 (Bolting & Screening (attaching steel mesh to walls and ceiling), Group 2 (Conventional Mining (using a hand-held drilling carriage to drills holes in rock walls and ceiling)), Group 3 (Support Services (mechanic, welder, pipe layer)), Group 4 (Production Drill (using a machine mounted drilling unit), Scooptram(TM) (ore transport with no air conditioner), Shotcrete (concrete applied by spraying)). Part #2- In-situ metabolic energy expenditures were estimated through indirect open circuit calorimetry and deep tissue and skin temperatures were measured for those same groups. Results. Part #1- twenty three common mining tasks were identified with differences identified between various group for time and intensity. Part #2- metabolic requirements between groups were similar with one difference identified between groups 3 and 4 (P &lt; 0.05). Deep tissue and skin temperatures did not change significantly through the course of a work day. Conclusion. Part #1- a variety of tasks is performed by each group and there is no uniform work protocol. Part #2- each mining group's metabolic energy expenditure requirements to perform various mining tasks are similar.

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