Objective: To explore cyberbullying and risk factors of middle school students, and to provide a reference for cyberbullying prevention in school settings. Methods: A stratified cluster random sampling method was used to select 12 940 students from three junior high schools and four senior high schools in Yixing City of Jiangsu Province, China, to conduct a questionnaire survey from March 1 to May 31, 2019. The Chi -square test was performed to compare differences in the prevalence of cyberbullying among groups with different sociodemographic characteristics, and the multivariate Logistic regression model was employed to analyze the risk factors. A risk predictive nomogram model was constructed and then verified. Results: Middle school students were found to be victims of cyberbullying at a rate of 12.3%. The Logistic regression results showed that alcohol use ( OR =1.93), lack of emotional management ( OR =1.30), feeling unsafe ( OR =1.70), not trusting people ( OR =1.66), increased daily online time ( OR =1.39), higher frequency of using social software or websites ( OR =2.24), poor relationships with family members ( OR =1.46), parental neglect ( OR =1.50), class leadership ( OR =1.30) and poor relationships with classmates ( OR =1.34) were risk factors for middle school students who were victims of cyberbullying ( P <0.05). Based on these 10 independent risk factors, the nomogram prediction model, had good discrimination ( AUC =0.73). Conclusion Cyberbullying is common among middle school students. Internet use, parental neglect and class leadership all have an impact on cyberbullying.

Objective:To investigate the epidemiology, evolution and transmission characteristics of HIV-1 CRF07_BC in Nanjing between 2015 and 2019 to provide scientific basis for precise prevention and control of HIV-1 transmission.Methods:Pol gene sequences of 319 patients with HIV-1 CRF07_BC infection in Nanjing were amplified and sequenced and a maximum likelihood phylogenetic tree was then constructed. Markov Chain Monte Carlo sampling method was used to generate Maximum Clade Credibility Tree. Bayesian Skyline Plot was used to reconstruct the changing trend of the effective population size. Pairwise gene distance method was used to construct molecular network to investigate the transmission features. Results:Among the 319 patients, 303 (95.0%) were male; 264 (82.8%) had multiple sexual partners; only 14 (4.4%) had been using condoms. Most of the infections were occurred in men who have sex with men (MSM), accounting for 77.4%. The maximum likelihood phylogenetic analysis of HIV-1 CRF07_BC revealed two clusters: Cluster1 and Cluster2. Cluster1 mainly contained the strains isolated from MSM and Cluster2 mainly consisted of the strains isolated from heterosexual patients. The most recent common ancestor was 2002.47(1999.91, 2005.43) year for Cluster1 and 1996.38(1992.55, 1999.76) year for Cluster2. The evolutionary rates (95% highest posterior density, 95%HPD) of Cluster1 and Cluster2 were 1.73×10 -3 (1.36×10 -3-2.16×10 -3) substitutions·site -1·year -1 and 2.09×10 -3 (1.50×10 -3 -2.79×10 -3 ) substitutions·site -1·year -1, respectively. The effective population sizes of Cluster1 and Cluster2 tended to be stable after 2002 and 2003, respectively. In addition, Cluster1 and Cluster2 formed eleven and eight unique branches, respectively, suggesting the possibility of divergent epidemics of this genotype. A total of 35 propagation clusters were formed in the molecular propagation network, including 92 Nanjing sequences with an average degree of 4.3. Males, MSM and people with multiple sexual partners were more likely to be connected to the network. Students and young patients were more likely to be connected to the network. Conclusions:HIV-1 CRF07_BC infection was characterized by low age, multiple sexual partners, unprotected behaviors and transmission among MSM in Nanjing from 2015 to 2019. It was recommended to pay more attention to students and young people, to formulate more effective prevention and control measures for high-risk sexual behaviors, and to carry out continuous molecular monitoring of CRF07_BC strain, so as to provide scientific basis for the prevention and control of HIV CRF07_BC.