Coking-Resistant Sub-Nano Dehydrogenation Catalysts: PtnSnx/SiO2 (n=4, 7)

We present a combined experimental/theoretical study of Pt$_n$/SiO$_2$ and Pt$_n$Sn$_x$/SiO$_2$ (n = 4, 7) model catalysts for the endothermic dehydrogenation of hydrocarbons, using the ethylene intermediate as a model reactant. Supported pure Ptn clusters are found to be highly active toward dehydrogenation of C2D4, quickly deactivating due to a combination of carbon deposition and sintering, resulting in loss of accessible Pt sites. Addition of Sn to Ptn clusters results in the complete suppression of C2D4 dehydrogenation and carbon deposition, and also stabilizes the clusters against thermal sintering. Theory shows that both systems have thermal access to a multitude of cluster structures and adsorbate configurations that form a statistical ensemble. While Pt4/SiO2 clusters bind ethylene in both di-sigma and pi-bonded configurations, Pt$_4$Sn$_3$/SiO$_2$ binds C2H4 only in the pi-mode, with di-sigma bonding suppressed by a combination of electronic and geometric features of the PtSn clusters. Dehydrogenation reaction profiles on the accessible cluster isomers were calculated using the climbing image nudged elastic band (CI-NEB) method

Air pollution and general practitioner access and utilization: a population-based study in Sarnia, ‘Chemical Valley’

Background: Health impacts of poor environmental quality have been identified in studies around the world and in Canada. While many of the studies have identified associations between air pollution and mortality or morbidity, few have focused on the role of health care as a potential moderator of impacts. This study assessed the determinants of health care access and utilization in the context of ambient air pollution in Sarnia, Ontario, Canada. Methods: Residents of Sarnia participated in a Community Health Study administered by phone, while several ambient air pollutants including nitrogen dioxide (NO2), sulphur dioxide (SO2) and the volatile organic compounds benzene, toluene, ethylbenzene, mp- and o-xylene (BTEX) were monitored across the city. Land Use Regression models were used to estimate individual exposures to the measured pollutants and logistic regression models were utilized to assess the relative influence of environmental, socioeconomic and health related covariates on general practitioner access and utilization outcomes. Results: The results show that general practitioner use increased with levels of exposure to nitrogen dioxide (NO2- Odds Ratio [OR]: 1.16, p \u3c 0.05) and sulphur dioxide (SO2- OR: 1.61, p \u3c 0.05). Low household income was a stronger predictor of having no family doctor in areas exposed to high concentrations of NO2 and SO2. Respondents without regular care living in high pollution areas were also more likely to report travelling or waiting for care in excess of 20 minutes (OR: 3.28, p \u3c 0.05) than their low exposure counterparts (OR: 1.11, p \u3e 0.05). Conclusions: This study provides evidence for inequitable health care access and utilization in Sarnia, with particular relevance to its situation as a sentinel high exposure environment. Levels of exposure to pollution appears to influence utilization of health care services, but poor access to primary health care services additionally burden certain groups in Sarnia, Ontario, Canada

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

Cancer and Construction: What Occupational Histories in a Canadian Community Reveal

From 2000 to 2002, male patients at a Canadian cancer treatment center with new-incident head-and-neck or esophageal cancers were invited to participate in a population-based study. The study population included 87 cases and 172 controls. A lifetime-history questionnaire was administered. Odds ratios (ORs) were calculated for occupational groups with a minimum of five cases, adjusted for duration of employment, age, smoking, alcohol, education, and income. A significantly increased risk was shown for construction workers (OR = 2.20; 95% CI 1.25–3.91). This investigation of a set of rare cancers over a limited time period demonstrates the feasibility of this research approach. The increased risk among construction workers supports the need for more comprehensive study of exposures in this occupational group

Electronic learning can facilitate student performance in undergraduate surgical education: a prospective observational study

BACKGROUND: Our institution recently introduced a novel internet accessible computer aided learning (iCAL) programme to complement existing surgical undergraduate teaching methods. On graduation of the first full cycle of undergraduate students to whom this resource was available we assessed the utility of this new teaching facility. METHOD: The computer programme prospectively records usage of the system on an individual user basis. We evaluated the utilisation of the web-based programme and its impact on class ranking changes from an entry-test evaluation to an exit examination in surgery. RESULTS: 74.4% of students were able to access iCAL from off-campus internet access. The majority of iCAL usage (64.6%) took place during working hours (08:00–18:00) with little usage on the weekend (21.1%). Working hours usage was positively associated with improvement in class rank (P = 0.025, n = 148) but out-of hours usage was not (P = 0.306). Usage during weekdays was associated with improved rank (P = 0.04), whereas weekend usage was not (P = 0.504). There were no significant differences in usage between genders (P = 0.3). Usage of the iCAL system was positively correlated with improvement in class rank from the entry to the exit examination (P = 0.046). Students with lower ranks on entry examination, were found to use the computer system more frequently (P = 0.01). CONCLUSION: Electronic learning complements traditional teaching methods in undergraduate surgical teaching. Its is more frequently used by students achieving lower class ranking with traditional teaching methods, and this usage is associated with improvements in class ranking

Socioeconomic inequalities in cancer survival in England after the NHS cancer plan

BACKGROUND: Socioeconomic inequalities in survival were observed for many cancers in England during 1981-1999. The NHS Cancer Plan (2000) aimed to improve survival and reduce these inequalities. This study examines trends in the deprivation gap in cancer survival after implementation of the Plan. MATERIALS AND METHOD: We examined relative survival among adults diagnosed with 1 of 21 common cancers in England during 1996-2006, followed up to 31 December 2007. Three periods were defined: 1996-2000 (before the Cancer Plan), 2001-2003 (initialisation) and 2004-2006 (implementation). We estimated the difference in survival between the most deprived and most affluent groups (deprivation gap) at 1 and 3 years after diagnosis, and the change in the deprivation gap both within and between these periods. RESULTS: Survival improved for most cancers, but inequalities in survival were still wide for many cancers in 2006. Only the deprivation gap in 1-year survival narrowed slightly over time. A majority of the socioeconomic disparities in survival occurred soon after a cancer diagnosis, regardless of the cancer prognosis. CONCLUSION: The recently observed reduction in the deprivation gap was minor and limited to 1-year survival, suggesting that, so far, the Cancer Plan has little effect on those inequalities. Our findings highlight that earlier diagnosis and rapid access to optimal treatment should be ensured for all socioeconomic groups