Analysis of a worker-based participatory action research approach to the identification of selected occupational health and safety problems in Canada using mapping

There are limitations to conventional occupational health and safety research approaches and practices and numerous barriers to overcome in order to achieve progress. Occupational health and safety is impacted by the broader social-political environment. Corporatism affects the directions, ideas and practice of regulators, educators, the labour movement, scientists, medical professionals, and society as a whole, thus inhibiting workers' power to influence change. The thesis therefore explores both the wider influences and barriers to occupational health and safety advances, focusing particularly on the Canadian situation, through the general research questions: What has influenced occupational health and safety policies and practices, especially in Canada? What are some of the limitations of conventional occupational health and safety research and practices? To what extent can participatory action research and mapping address identified limitations? These questions are explored from the perspective of the population potentially at risk. New theories and approaches to occupational health and safety research are then applied in this thesis in order to explore a more specific multi-part research question: Can mapping within worker-based participatory action research be used to explore occupational health and safety conditions? In particular, can mapping contribute to occupational health and safety improvements at a local level and beyond; establish workers' previous exposures for compensation purposes; support efforts to bring about justice through compensation for workers affected by unsafe working conditions; and raise worker and public awareness of health and safety? These questions are explored through two different case studies, which examine, in depth, occupational health and safety action and possible remedies. Casino gaming workers in Windsor, Ontario, Canada undertook a collaborative study to investigate and improve current health and safety conditions. Former Holmes foundry and asbestos insulation workers in Sarnia, Ontario, Canada undertook a collaborative study to provide evidence of exposures and ensuing health problems to support claims for compensation. The outcomes of the case studies shed light on the bigger Canadian health and safety picture and demonstrate that mapping as a data collection method used within a participatory action research approach can accomplish a broad range of objectives. Mapping can raise workers' awareness, facilitate communication, build solidarity and cohesiveness, foster community support, mobilise workers to take action to reduce hazards or win compensation, in turn influencing employers, the compensation board and government agencies. The case studies accomplished the shared objective of raising worker and public awareness. The casino workers also gained occupational health and safety improvements and the Holmes workers were successful in gaining compensation

Effects of a series of triorganotins on ATP levels in human natural killer cells

Natural killer (NK) cells are our initial immune defense against viral infections and cancer development. Thus, agents that are able to interfere with their function increase the risk of cancer and/or infection. A series of triorganotins (trimethyltin (TMT), dimethylphenyltin (DMPT), methyldiphenyltin (MDPT), and triphenyltin (TPT)) have been shown to decrease the lytic function of human NK cells. TPT and MDPT were much more effective than DMPT or TMT at reducing lytic function. This study investigates the role that decreased ATP levels may play in decreases in the lytic function of NK cells induced by these organotins (OTs). A 24h exposure to as high as 10μM TMT caused no decrease in ATP levels even though this level of TMT caused a greater than 75% loss of lytic function. TPT at 200nM caused a decrease in ATP levels of about 20% while decreasing lytic function by greater than 85%. There was no association between ATP levels and lytic function for any of the compounds when NK cells were exposed for 1 or 24h. However, after a 48h exposure to both DMPT and TPT decreased lytic function was associated with decreased ATP levels. There was an association between decreased lytic function and decreased ATP levels after a 6-day exposure to each of the four compounds. These studies indicate that the loss of lytic function seen after 1 and 24h exposures to this series of organotins cannot be accounted for by decreases in ATP. However, after longer exposures loss of lytic function may be in part be attributable to inadequate ATP levels

Surface Wave Multipath Signals in Near-Field Microwave Imaging

Microwave imaging techniques are prone to signal corruption from unwanted multipath signals. Near-field systems are especially vulnerable because signals can scatter and reflect from structural objects within or on the boundary of the imaging zone. These issues are further exacerbated when surface waves are generated with the potential of propagating along the transmitting and receiving antenna feed lines and other low-loss paths. In this paper, we analyze the contributions of multi-path signals arising from surface wave effects. Specifically, experiments were conducted with a near-field microwave imaging array positioned at variable heights from the floor of a coupling fluid tank. Antenna arrays with different feed line lengths in the fluid were also evaluated. The results show that surface waves corrupt the received signals over the longest transmission distances across the measurement array. However, the surface wave effects can be eliminated provided the feed line lengths are sufficiently long independently of the distance of the transmitting/receiving antenna tips from the imaging tank floor. Theoretical predictions confirm the experimental observations

Microvascular resistance predicts myocardial salvage and infarct characteristics in ST-elevation myocardial infarction

<b>Background:</b> The pathophysiology of myocardial injury and repair in patients with ST‐elevation myocardial infarction is incompletely understood. We investigated the relationships among culprit artery microvascular resistance, myocardial salvage, and ventricular function.<p></p> <b>Methods and Results:</b> The index of microvascular resistance (IMR) was measured by means of a pressure‐ and temperature‐sensitive coronary guidewire in 108 patients with ST‐elevation myocardial infarction (83% male) at the end of primary percutaneous coronary intervention. Paired cardiac MRI (cardiac magnetic resonance) scans were performed early (2 days; n=108) and late (3 months; n=96) after myocardial infarction. T2‐weighted‐ and late gadolinium–enhanced cardiac magnetic resonance delineated the ischemic area at risk and infarct size, respectively. Myocardial salvage was calculated by subtracting infarct size from area at risk. Univariable and multivariable models were constructed to determine the impact of IMR on cardiac magnetic resonance–derived surrogate outcomes. The median (interquartile range) IMR was 28 (17–42) mm Hg/s. The median (interquartile range) area at risk was 32% (24%–41%) of left ventricular mass, and the myocardial salvage index was 21% (11%–43%). IMR was a significant multivariable predictor of early myocardial salvage, with a multiplicative effect of 0.87 (95% confidence interval 0.82 to 0.92) per 20% increase in IMR; P<0.001. In patients with anterior myocardial infarction, IMR was a multivariable predictor of early and late myocardial salvage, with multiplicative effects of 0.82 (95% confidence interval 0.75 to 0.90; P<0.001) and 0.92 (95% confidence interval 0.88 to 0.96; P<0.001), respectively. IMR also predicted the presence and extent of microvascular obstruction and myocardial hemorrhage.<p></p> <b>Conclusion:</b> Microvascular resistance measured during primary percutaneous coronary intervention significantly predicts myocardial salvage, infarct characteristics, and left ventricular ejection fraction in patients with ST‐elevation myocardial infarction.<p></p&gt

Sex Ratio Changes as Sentinel Health Events of Endocrine Disruption

The production and widespread use of synthetic chemicals since the 1940s have resulted in ubiquitous contamination of fish, wildlife and human populations. Since the 1960s, observers have documented major damage to wildlife reproduction across the globe, and subsequently, damage to reproductive health in exposed humans as well. The sex ratio in human communities and populations can be readily measured to ascertain whether reproductive effects, such as subtle birth defects of the reproductive tract caused by exposures to chemicals, might be occurring. Male to femalesex ratios appear to be declining in populations in several parts of the globe, possibly as a result of prenatal exposures to chemicals. Sex ratio data for communitieswith unusual occupational or environmental exposures can be compiled using traditional epidemiological techniques in pursuit of environmental justice. Local, regional and national population health researchers and occupational hygienists can use health statistics toexamine sex ratios as sentinel health events that might portend patterns of subtle structural birth defects of the reproductive tract and functional deficits in neurodevelopment

Occupational Histories of Cancer Patients in a Canadian Cancer Treatment Centre and the Generated Hypothesis Regarding Breast Cancer and Farming

Occupational exposures increase cancer risks. The Windsor Regional Cancer Centre in Windsor, Ontario, was the first Canadian cancer treatment center to collect the work histories of its patients, which were recorded using a computer-based questionnaire. Breast cancer cases represented the largest respondent group. The lifetime occupational histories of 299 women with newly diagnosed breast cancers were compared with those of 237 women with other cancers. Odds ratios (ORs) were calculated using logistic regression, adjusting for age, social class, and education. The OR for women £ 55 years of age with breast cancer who had ever farmed, compared with women of the same age with other cancers, was 9.05 (95% CI 1.06, 77.43). Patients’ occupational histories can help to inform understanding of cancer etiology and prevention. This effort points to a need for investigation of the possible association between breast cancer and agricultural hazards such as pesticides

Attributable costs of enterococcal bloodstream infections in a nonsurgical hospital cohort

BACKGROUND: Vancomycin-resistant enterococcal (VRE) bloodstream infections (BSI) are associated with increased morbidity and mortality. OBJECTIVE: To determine the attributable costs of vancomycin-sensitive (VSE) and VRE BSI and the independent impact of vancomycin-resistance on hospital costs. METHODS: A retrospective cohort study was conducted of 21,154 non-surgical patients admitted to an academic medical center between 2002 and 2003. Using administrative data, attributable hospital costs (inflation adjusted to $2007) and length of stay were estimated with multivariate generalized least squares (GLS) models and propensity score matched-pairs. RESULTS: The cohort included 182 VSE and 94 VRE BSI cases. After adjustment for demographics, comorbidities, procedures, non-enterococcal BSI, and early mortality, the attributable costs of VSE BSI were$2,250 (95% confidence interval [CI], $1,758–$2,880) in the standard GLS model and $2,023 (95$1,588–$2,575) in the propensity-score weighted GLS model and the attributable costs of VRE BSI were$4,479 (95% CI, $3,500–$5,732) in the standard GLS model and $4,036 (95$3,170–$5,140) in the propensity-score weighted GLS model. The median of the difference in costs between matched-pairs was$5,282 ($2,042–$8,043) for VSE BSI and $9,949 (95$1,579–$24,693) for VRE BSI. The attributable costs of vancomycin-resistance were$1,713 (95% CI, $1,338–$2,192) in the standard GLS model and $1,546 (95$1,214–$1,968) in the propensity-score weighted GLS model. Attributable length of stay ranged from 1.1–2.2 days for VSE BSI and 2.2–3.5 days for VRE BSI cases. CONCLUSIONS: VSE and VRE BSI were independently associated with hospital costs and length of stay. Vancomycin-resistance was associated with increased costs

Expression of Cre recombinase during transient phage infection permits efficient marker removal in Streptomyces

We report a system for the efficient removal of a marker flanked by two loxP sites in Streptomyces coelicolor, using a derivative of the temperate phage φC31 that expresses Cre recombinase during a transient infection. As the test case for this recombinant phage (called Cre-phage), we present the construction of an in-frame deletion of a gene, pglW, required for phage growth limitation or Pgl in S.coelicolor. Cre-phage was also used for marker deletion in other strains of S.coelicolor

Expression of Cre recombinase during transient phage infection permits efficient marker removal in Streptomyces

We report a system for the efficient removal of a marker flanked by two loxP sites in Streptomyces coelicolor, using a derivative of the temperate phage φC31 that expresses Cre recombinase during a transient infection. As the test case for this recombinant phage (called Cre-phage), we present the construction of an in-frame deletion of a gene, pglW, required for phage growth limitation or Pgl in S.coelicolor. Cre-phage was also used for marker deletion in other strains of S.coelicolor

The speaking vocabulary of grade two

Thesis (M.A.)--Boston Universit