Analysis of surrounding rock damage law of TBM tunneling roadway in coal mine jointed strata

In order to research surrounding rocks failure characters and behaviors of TBM tunneling roadway in jointed strata, the paper takes methane drainage roadway of 1413A fully mechanized coal face in Zhangji　Coal Mine as engineering case, the surrounding rocks failure characters and behaviors under TBM tunneling condition was studied by establishing UDEC discrete element method numerical model according to the site lithological conditions, joint development characteristics and geo-stress field conditions. The research results show that: joints and fracture distribution characters are main influential elements of roadway surrounding rock failure; damage and failure of rocks are prone to happen on the cross area of joints; in engineering practices, roof support and collapse prevention should be taken as the first priority. In-situ monitoring results are in good agreements with simulation results and the adopted research methodology are able to represent the in-situ conditions

Role of remnant cholesterol in the relationship between physical activity and diabetes mellitus: an intermediary analysis

ObjectiveThe purpose of this investigation was to evaluate the potential link between physical activity (PA) and the heightened susceptibility to diabetes mellitus (DM), by examining whether remnant cholesterol (RC) might act as a mediator in this correlation.MethodsThe research utilized data from the National Health and Nutrition Examination Survey, spanning from 2005 to 2018. Various statistical analyses were conducted for continuous and categorical variables, including the t-test, ANOVA, and χ2 test. Logistic regression was employed to analyze the association between PA and DM across three distinct models. Mediation analysis was also conducted to assess the potential mediation effects of RC.ResultsThe study encompassed a total of 9,149 participants, and it was observed that individuals with DM exhibited lower levels of PA. Furthermore, PA levels were found to be associated with all participant characteristics except poverty income ratio, fasting blood glucose, and HOMA-IR (p < 0.05). After adjusting for covariates (Model 3), individuals with high PA levels demonstrated a decreased likelihood of developing DM compared to those in the low PA group (OR: 0.73, 95%CI: 0.54–0.99). A significant dose–response relationship was identified (p < 0.05). No interaction between PA and RC in relation to DM risk was detected, and RC was found to serve as a mediator in the connection between PA and DM. After considering covariates, the mediating effect of RC between PA and DM weakens.DiscussionOur findings suggest that higher levels of PA are linked to a reduced risk of DM in U.S. adults, with RC likely playing a mediating role