Association for combined exposure to job strain, shift work on mental health among Chinese railway workers: a cross-sectional study.

OBJECTIVES: The aim of this study was to assess the effects of coexposure to job strain and shift work on mental health in railway workers. DESIGN: Cross-sectional study. SETTING: One Railway Bureau Group in China. PARTICIPANTS: A total of 1270 front-line railway workers. OUTCOME MEASURES: The Symptom Checklist-90-Revised questionnaire was used to measure general mental health. Job strain variables were derived from the Job Content Questionnaire. Based on the records of the work schedule 3 months prior to the survey, the following three shift types were identified: fixed day, fixed night and rotating night shifts. Risks associated with mental health were assessed by carrying out logistic regression analysis which was adjusted for age, job tenure, smoking and exercise. Additionally, a crossover analysis was employed for the combined effects. RESULTS: High levels of job strain were linked to a higher risk of poor mental health (OR=1.53, 95% CI: 1.10 to 2.11). After adjusting for confounding factors, night shifts and rotating night shifts were significant risk factors for mental health (OR=2.21, 95% CI: 1.60 to 3.07; OR=2.36, 95% CI: 1.73 to 3.22). Compared with participants who experienced a low level of job strain and day shifts, those with a high level of job strain and who worked rotating shifts were at the highest risk of poor mental health (OR=4.68, 95% CI: 2.91 to 8.04), whereas the influence of a low level of job strain and rotating night shifts was not statistically significant. CONCLUSION: Job strain and night shifts among workers were associated, both independently and in combination, with an increased risk of poor mental health. Our data suggest that job strain contributes to the risk of poor mental health by means of a combined effect with shift work.

Multiple Effects of Iron and Nickel Additives on the Properties of Proton Conducting Yttrium-Doped Barium Cerate-Zirconate Electrolytes for High-Performance Solid Oxide Fuel Cells.

Transition metal oxides have been used as sintering aids for proton-conducting barium cerate-zirconates, which are promising electrolyte materials for low-temperature solid oxide fuel cells (SOFCs) and high-performance electrochemical membrane reactors. However, the effects of the additives on properties other than the density of the electrolytes have been ignored. Here, we report our findings that transition metal additives also affect the electrical properties, stability, and even catalytic activity of proton-conducting ABO3-type perovskites. BaCe0.7Zr0.1Y0.2O3-δ (BCZY) is selected as the basic material, and 2 mol % of Ni1-xFex (x range: from 0 to 1.0) oxides and 4 mol % of FeO1.5 are, respectively, added into BCZY to prepare electrolytes of anode-supported SOFCs. All of the electrolytes with additives can be densified after sintering at 1400 °C for 5 h, while BCZY without additive is porous. X-ray diffraction (XRD) spectra show that Ni and Fe are doped into the lattice of BCZY. For the first time, we find a positive function of Fe additive in BCZY that it not only acts as a good sintering aid but also improves the electrical performance and stability of the BCZY electrolyte in CO2 and H2O at reduced temperatures. The cell with the 2 mol % Ni0.5Fe0.5-doped BCZY electrolyte, with an unoptimized cathode, gives a power density of 973 mW cm-2 at 700 °C, 120 mW cm-2 at 450 °C, and 45 mW cm-2 at 350 °C. It operates under a constant current of 800 mA cm-2 at 650 °C for over 200 h, during which the voltage decreases from 0.73 to 0.71 V. A newly discovered densified layer, formed in the cathode during the SOFC operation, may cause the degradation.