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Abstract Safety assessment and safety warning in intelligent railway play an important role in safety management. This paper utilizes the PSO algorithm with bounds and time-varying attractor to obtain some parameters in the safety assessment model. Firstly, the safety assessment model is provided to evaluate the safety status on the existing problem, railway equipment and railway worker. Secondly, one objective function and three constraint conditions on training the safety assessment model are introduced to minimize the square error between the output and the safety classification level. Thirdly, it is important to discuss the convergence behavior and spectral radius on transfer matrix in the PSO algorithm with bounds and time-varying attractor. Finally, in order to show and demonstrate the effectiveness of the PSO algorithm, it is important to analyze the objective fitness, the swarm velocity, the time-varying attractor, the parameters in the safety assessment model and the computational time during the evolutionary process. And the PSO algorithm with bounds and time-varying attractor can solve parameter optimization problem on the railway safety assessment and warning.

AbstractBackground Patients with walled-off necrosis (WON) are still challenging to treat safely and effectively. Recently, double-pigtail plastic stents (DPS), bi-flanged metallic stents (BFMS), and lumen-apposing metal stents (LAMS) have been employed with endoscopic ultrasound-guided (EUS-guided) drainage. However, there is little solid evidence to support the effectiveness and safety of using stents. This study aims to compare the outcomes of the LAMS and the PS.Method Till July 2022, a thorough database search was done, and studies that met the criteria were chosen. By using the RevMan software, the technical and clinical success and other secondary outcomes were calculated. Subgroup analysis was performed between the LAMS and the BFMS.Results Fifteen studies (two randomized controlled trials and thirteen observational) with 687 patients receiving metal stents and 771 patients receiving plastic stents were selected for final analysis. There was no significant risk of bias or publication bias. The odds ratios (OR) for technical and clinical success were 0.36 (95% confidence interval (95% CI) 0.08, 1.52) and 2.26 (95%CI 1.62, 3.15), respectively. The OR for overall adverse events was 0.74 (95% CI 0.41, 1.34). In subgroup analysis, the LAMS and the BFMS showed the same outcomes.Conclusion Compared to DPS, LAMS had better clinical outcomes and fewer side effects when treating patients with WON.

AbstractBackground/Aims Pancreatic fluid collections (PFC) are debris or fluid of the pancreas that needs to be drained out. This may result from surgery or necrotizing pancreatitis. This meta-analysis compared the outcomes of PFC through endoscopic and percutaneous interventions.Methods A medical database was searched up to June 2022, comparing the outcomes of endoscopic drainage (ED) and percutaneous drainage (PD) for the PFC. Eligible studies reporting clinical and technical success and adverse events were selected.Results Seventeen studies with 1170 patients were included for meta-analysis, of which 543 patients underwent ED and 627 underwent PD. The odd ratio (OR) of technical success was 0.81 (95% confidence interval (CI) 0.31, 2.1) and clinical success was in the favor of the ED group at OR 2.23 (95% CI 1.45, 3.41). Adverse events OR 0.62 (95% CI 0.27, 1.39) and stent migration OR 0.61 (95% CI 0.10, 3.88) were the same in both groups, but hospital stay pooled mean difference of 15.02 days (95% CI 9.86, 20.18), mortality OR 0.24 (95% CI 0.09, 0.67), and re-interventions OR 0.25 (95% CI 0.16, 0.40) favored ED.Conclusions ED is safe and efficient for PFC with higher clinical success, lower mortality rate, hospital stay, and re-interventions compared with PD.

BACKGROUND Heavy metal pollution in the soil of mining areas is a serious threat to the ecological environment and the health of surrounding residents, and it is of great significance to effectively supervise it. The Xishimen iron deposit in Hebei Province is a large magnetite deposit in the Hanxing area. Comprehensive research on soil heavy metal pollution in this mining area is urgently needed. OBJECTIVES To evaluate soil heavy metal pollution in the Xishimen iron mining area in Hebei Province. METHODS The No.1 mining area of the Xishimen iron deposit was selected as the research object. ICP-MS was used to determine the heavy metal content. The exceedance rate, pollution sources and spatial distribution characteristics of heavy metals were obtained by descriptive statistical analysis, multivariate statistical analysis and spatial interpolation analysis, and the pollution risk was evaluated by combining the single factor pollution index, Nemero comprehensive pollution index and potential ecological hazard index. RESULTS Descriptive statistical analysis showed that the exceedance rate of Co in the mining area was 75.83%, indicating heavy pollution, while the exceedance rates of Cu, Cd and As were 14.70%, 21.40% and 13.29%, indicating moderate to light pollution. The exceedance rates of Cr, Ni, Zn, Pb and Hg were less than 5%, which were light pollution. The multivariate statistical analysis showed that Cr, Ni, Zn, Cd, As and Pb were from the natural weathering environmental pollution in the mineralized area, and Co and Cu were from the anthropogenic environmental pollution caused by mining production and fertilizer use. Hg came from the local pollution caused by human factors. Spatial interpolation analysis showed that the nine heavy metals had a high distribution in the open pit mining area on both sides of the Mahui River and a low distribution in the rivers and residential areas. The Nemero comprehensive pollution index of heavy metals in the study area was 13.49, and the comprehensive ecological risk index was 55.50. CONCLUSIONS The results indicate that there is Hg, Co, and Cu pollution caused by human factors in the mining area, which needs to be addressed. The heavy metal pollution in this area is serious but the ecological risk is still in a controllable range.