BackgroundPublished studies in comparing pre and post the COVID-19 pandemic depression and anxiety levels among children and adolescents yielded incongruent results. Therefore, there is a necessity to perform a timely meta-analysis to synthesize existing evidence.MethodsA total of 10 digital databases (PubMed, Web of Science, PsycINFO, the Cochrane Library, Embase, Scopus, ScienceDirect, CNKI, WanFang, CQVIP) were fully searched for eligible studies published before November 6, 2021. Based on quality assessment results, relevant data were extracted for eligible studies of higher quality. We combined standardized mean difference (SMD) or prevalence ratio (RR) for anxiety and depression pre and post the COVID-19 pandemic by using random-effects models. Sensitivity analysis was further performed to evaluate heterogeneity of included studies.Results14,508 articles were preliminarily identified, and after stepwise screening process, 8 articles were included eventually. The results showed that the SMD for post COVID-19 anxiety score measured by GAD-7 was 0.12 (95% CI: 0.08, 0.17), an significant increase compared with pre COVID-19 period; the SMDs and 95% CIs for post COVID-18 depression scores measured by PHQ-9, PHQ-8, and MFQ were 0.17 (95% CI: 0.10, 0.24), 0.23 (95% CI: 0.08, 0.38), and 0.11 (95% CI: 0.06, 0.17), respectively, also significantly increased compared with pre COVID-19 period. The RR for depression was 2.54 (95% CI: 2.48, 2.60) in post COVID-19 period when compared with pre-pandemic.ConclusionsChildren and adolescents reported deteriorated anxiety and depression levels after the COVID-19 pandemic. More attention should be paid to this vulnerable group. Effective, expedient, and practical intervention measures which are compatible with COVID-19 prevention and control policies should be developed and implemented to maintain mental health wellbeing of the youths.

Background School bullying victimization is associated with increased risk of anxiety in children and adolescents. However, little is known about the role of resilience in this association. The purpose of this study was to investigate the possible mediation by resilience in this association in a large group of Chinese children and adolescents. Methods A population-based cross-sectional study adopting two-stage simple random cluster sampling was implemented in Yunnan province, southwestern China. A comprehensive questionnaire was used to collect information from the participants. Among all the participants, 4624 were included in the final analysis. Descriptive statistics were used to present general characteristics of the study participants. Univariate and multivariate logistic regression models were adopted to estimate crude and adjusted associations among bullying victimization, anxiety, and resilience. A path model was used to analyze the hypothesized mediation by resilience in the association between bullying victimization and anxiety. Results Analytical results of multivariate logistic regression models suggested that bullying victimization was significantly associated with anxiety in Chinese children and adolescents; compared with individuals who had not been bullied, victims of bullying were more likely to experience anxiety symptoms, with an adjusted odds ratio (OR) of 3.02 (95% CI 2.46–3.71). Path analysis revealed a prominent mediating effect of resilience in the association between bullying victimization and anxiety, accounting for 31.89% of the total association. Further analysis indicated that, among the five dimensions of resilience, emotional regulation, interpersonal assistance, and family support were significant mediators, accounting for 30.34%, 10.79%, and 8.35% of the total association. Conclusions Our major findings highlighted the promising role of resilience-based intervention measures in reducing the risk of anxiety associated with school bullying victimization in Chinese children and adolescents.

Liver cancer is a major public health challenge. Few published studies reported temporal trend and geographical distribution of liver cancer mortality in China, especially in less developed southwest regions with higher liver cancer incidence. In the current study, we obtained liver cancer mortality data from population-based death surveillance system in Yunnan province in 2015–2019. The mortality of liver cancer was analyzed by using the joinpoint regression model. The space distribution of liver cancer mortality in 129 counties and districts in Yunnan province was illustrated by using the ArcGIS software. Moran's I method was used to estimate the global and local spatial autocorrelation of liver cancer mortality. Analytical results revealed that from 2015 to 2019, the average mortality rate of liver cancer in Yunnan province was 12.96/100,000, with an average annual growth rate of 6.26% (p < 0.05). Higher liver cancer mortality was found in rural areas and in males. Moreover, people aged 45–50 years experienced a steep increase in liver cancer mortality rate. High-high cluster was mainly consisted of areas with higher hepatitis virus infection rate or severe intravenous drug use problem. Our study results suggest a heavy burden of liver cancer in southwest China Yunnan province. Comprehensive intervention measures need to be developed and implemented.

Background Existing evidence has shown that negative parenting style elevates the risk of school bullying victimization in children and adolescents. Resilience may play as a mediating factor in this association. However, this hypothesis has not been investigated. Methods In this cross-sectional study, a total of 4582 Chinese children and adolescents had been surveyed by self-administered questionnaire. The Chinese version of Egna Minnen av. Barndoms Uppfostra (s-EMBU-C), the Olweus Bully/Victim Questionnaire (OBVQ) and the Resilience Scale for Chinese Adolescents (RSCA) were used to collect relevant information. Univariate and multiple logistic regression models were used to estimate the crude and adjusted associations between parenting style, resilience, and bullying victimization. Path analysis was used to estimate the mediation via resilience in the association between parenting style and bullying victimization. Results After adjustment for possible covariates, the results of multivariate binary logistic regression model suggested that among all dimensions of parenting style, mother’s and father’s rejection were significantly associated with school bullying victimization. Path analysis revealed a statistically significant mediation of resilience in the association between parental rejection and bullying victimization, and among the five dimensions of resilience, emotion regulation, family support and interpersonal assistance accounted for the highest proportions of mediation. Conclusions For children and adolescents who suffered from parental rejection, building up resilience, especially those measures aiming at improving emotion regulation ability and consolidating family and peer support, might be effective in reducing risk of school bullying victimization.

A new type of non-pneumatic tire with a flexible spoke structure is proposed to solve traditional pneumatic tire defects, such as easy bursting, the requirement of real-time maintenance to keep tire pressure, and a complex manufacturing process. The thermal mechanical coupling characteristics of the flexible spoke non-pneumatic tire are studied in detail to obtain the steady-state temperature field distribution pattern under different operating conditions. A unit configuration method is proposed to build the 3D model of the flexible spoke non-pneumatic tire. Then, the thermal-mechanical sequential coupling method is used to analyse the deformation, energy loss and heat conduction of the flexible spoke non-pneumatic tire. Finally, the steady-state temperature field distribution pattern under thermal-mechanical coupling is obtained. The results show that the high temperature region of the non-pneumatic tire is mainly distributed in the middle bending part of the flexible spoke unit, and the temperature gradually decreases from the centre of the flexible spoke to the surrounding parts. The influence of load on the temperature change of non-pneumatic tire is greater than that of the driving speed. This study provides a theoretical basis and method guidance for solving the failure problem of the non-pneumatic tires under the action of thermal-mechanical coupling.