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The multi-objective optimisation of high-speed rail profile with small radius curve is studied in the paper. A multi-objective mathematical model for rail profile optimisation of high-speed railway is established. The CN60 rail profile is parameterised into a series of generalised functions of design variables. In order to guarantee the smoothness of the rail profile and meet the maximum grinding depth of rail in China, the constraints are employed. The wheel-rail vertical clearance and equivalent conicity of wheelset are taken as objective functions, and a rail wear prediction programme is compiled. Contact line method is employed to complete the detection algorithm of wheel-rail contact points. Finally, NSGA-II Algorithm is adopted to solve the Pareto-optimal front of the optimisation model. A set of solutions are retrieved from the Pareto optimal front solution as the optimised profile. The optimised rail profile and the original rail profile are matched with the LMA wheel profile (a certain worn type of wheel profiles for EMU in China) respectively. It is testified that the rail profile could effectively reduce the rail wear and improve curving performance. The new method proposed in this paper can provide some reference for the optimisation design of high-speed rail profile with small radius curve. [ABSTRACT FROM AUTHOR]

Problem-based learning (PBL) is defined as a student-centered pedagogy which can provide learners more opportunities for application of knowledge acquired from basic science to the working situations than traditional lecture-based learning (LBL) method. In China, PBL is increasingly popular among preventive medicine educators, and multiple studies have investigated the effectiveness of PBL pedagogy in preventive medicine education. A pooled analysis based on 15 studies was performed to obtain an overall estimate of the effectiveness of PBL on learning outcomes of preventive medicine. Overall, PBL was associated with a significant increase in students' theoretical examination scores (SMD = 0.62, 95% CI = 0.41-0.83) than LBL. For the attitude- and skill-based outcomes, the pooled PBL effects were also significant among learning attitude (OR = 3.62, 95% CI = 2.40-5.16), problem solved skill (OR = 4.80, 95% CI = 2.01-11.46), self-directed learning skill (OR55.81, 95% CI53.11-10.85), and collaborative skill (OR54.21, 95% CI5 0.96-18.45). Sensitivity analysis showed that the exclusion of a single study did not influence the estimation. Our results suggest that PBL of preventive medicine education in China appears to be more effective than LBL in improving knowledge, attitude and skills. [ABSTRACT FROM AUTHOR]

Background: Many studies have linked ambient fine particulate matter (PM2.5) air pollution to different cardiopulmonary diseases in the general population. However the complex mechanisms underlying PM2.5-induced adverse health effects are not yet to be fully elucidated., Method: In this study, we aimed to identify genes and pathways that may contribute to PM2.5-induced lung toxicity in humans through genome-wide approaches. Human bronchial epithelial (HBE) cells, exposed to various concentrations of PM2.5 collected from Wuhan, China, showed decreased cell viability in a dose-dependent manner. HBE cells were exposed to 200 μg/ml and 500 μg/ml PM2.5 and microarrays were used to obtain a global view of the transcriptomic responses., Results: A total of 970 and 492 genes were identified that significantly changed after 200 μg/ml and 500 μg/ml PM2.5 exposures, respectively. PM2.5 induced a large number of genes involved in inflammatory and immune response, response to oxidative stress, and response to DNA damage stimulus, which might contribute to PM2.5 related cardiopulmonary diseases. Pathway analysis revealed that different dose of PM2.5 triggered partially common disturbed pathways. Flow cytometry assay evidenced that there were statistically significant differences in the G1 phase of cell cycle after low or high-dose PM2.5 exposure when compared to the unexposed controls. Only high-dose PM2.5 significantly increased the proportion of cells in the S phase of cell cycle., Conclusion: We identified many genes and pathways that altered significantly in HBE cells after PM2.5 exposures. These findings are important in providing further understanding of the mechanisms underlying PM2.5-induced adverse health effects., (Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.)