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Background: The incidence of childhood obesity is increasing. There is some controversy about the association between overweight and nonalcoholic fatty liver disease (NAFLD) in children. This article intends to compare the differences in these obesity related parameters between NAFLD children and healthy control children through meta-analysis to provide evidence-based medical evidence for clinical use. Methods:The literature were extracted from English and Chinese databases. Statistical analysis was performed using Stata/SE 16.0, IBM SPSS Statistics 26, and Review Manager 5.4 software.Results: A total of 15 original case control studies were included, including 12 high-quality literature, 3 medium quality literature. The total sample size included in the analysis was 1,595 children, including 824 in the experimental group and 771 in the control group. The results of meta-analysis showed that the body mass index (BMI) of the NAFLD group was significantly higher than that of the control group [mean difference (MD) =1.05, 95% confidence interval (CI): 0.36-1.73]. Waist circumference of the NAFLD group was significantly larger than that of the control group (MD =1.66, 95% CI: 0.60-2.73). Triglyceride level in the NAFLD group was significantly higher than that in the control group (MD =1.08, 95% CI: 0.05-2.12). Low-density lipoprotein (LDL) level in the NAFLD group was significantly higher than that in the control group (MD =0.49, 95% CI: 0.12-0.85). In addition, fasting blood glucose of the NAFLD group was significantly higher than that of the control group (MD =0.31, 95% CI: 0.09-0.54) and insulin resistance index of the NAFLD group was significantly higher than that of the control group (MD =2.95, 95% CI:1.41-4.49). Exercise had a significant effect on improving the degree of NAFLD in children [odds ratio (OR) =2.51, 95% CI: 1.83-3.43].Conclusions: Various physical indicators were related to obesity, including BMI, waist circumference, triglyceride content, LDL, fasting blood glucose, and insulin resistance index, and all were significantly correlated with NAFLD in children, provided a reference for future clinical diagnosis and treatment work.In addition, exercise could significantly improve the degree of steatosis in children with NAFLD.

The hazardous effect of a mine earthquake on a roadway is not only related to its energy scale but also to its distance from the roadway. In this study, a signal attenuation model and a disaster-causing model were established to evaluate the mine earthquake effects based on peak particle velocity (PPV) data recorded for 37221-1 upper roadway of the Dongxia Coal Mine, China. The characteristic of dynamic loads due to mine earthquake propagation to roadway surfaces was researched, and critical PPV values were identified using FLAC3D numerical simulation, which can be used to evaluate the roadway anti-burst performance under the existing support system. The results show that the support system is able to resist a mine earthquake with energy below 2.33 × 103 J; however, considering the energy accumulation volume of surrounding rocks and the range of source fracture, the maximum resistible mine earthquake energy can be up to 7.09 × 106 J when the roadway is 50 m away from the source. The validity and applicability of the disaster-causing models was verified by two rockburst cases that occurred during the excavation of the working face.

Seismic hazards are typical mining hazards causing dynamic failure of coal and rock mass, which greatly threatens the safety of personnel and equipment. At present, various seismic analysis methods are used to assess seismic risks but their accuracy is significantly limited by the incompleteness of seismic data. The probability of detecting earthquakes (PDE) method has been proven as a powerful means for retrieving missed seismic events and enhancing the seismic data integrity in mines. However, to date, the reliability of the results of the PDE method has not been assessed and the highly integrated seismic data have not been linked with the actual hazard potential. To fill these gaps, this paper investigated the impacts of the seismic data volume used for calculation and the modification of the layout of sensors on the reliability and robustness of the PDE method. The event counts and seismic energy were compensated using the PDE method, correlated with strong seismic events. The results indicated that the compensated seismic data presented higher accuracy in locating future hazardous events than before. This research provides references on enhancing the performance of seismic analysing methods for seismic risk assessments.

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