Objective To investigate online dating status and human immunodeficiency virus (HIV)infection among men who have sex with men (MSM)in Chongqing,and provide basis for effective intervention in HIV infec-tion among MSM.Methods 206 MSM in Chongqing were performed structured interview and questionnaire survey, MSM who didn’t conduct HIV testing within half a year were performed laboratory screening,sociological popula-tion characteristics and influencing factors of HIV in MSM were analyzed.Results The average age of 206 MSM was (22.08±1 .81)years old,137 (66.50%)received college education and above,HIV infection rate was 21 .36%(44/206).HIV infection rate in MSM who had no fixed partners was higher than those who had fixed partners;the more sexual partners they had,the greater the risk of HIV infection they got;HIV infection rate in MSM who had sex with unfamiliar persons or strangers was higher than those who had sex with familiar partners;the higher rate of condom use in sexual behavior,the lower rate of HIV infection was,there were significant differences among the groups(all P <0.05).Condom use among MSM with different educational levels was significantly different(all P <0.05).Conclusion HIV infection rate in MSM is high in this city,it is necessary to strengthen education about health,network partner,and behavioral intervention,reduce the bridge population connecting MSM network,es-tablish social support system of homosexuality,and reduce the risk of HIV infection in MSM.

Objective To examine the current status of the sexual behavior among out‐of‐school adolescent men who have sex with men(MSM)and analyze the influential factors of AIDS infection in order to provide countermeasures.Methods The software SPSS 16.0 was used for cross table analysis and chi square test of questionnaire data and HIV detection data.Results The HIV infection rate was 21.36%.The household registration ,the only child ,living state ,coming out of the closet ,fixed sex‐ual partner ,the way they know sexual partners had no significant effects on HIV infection(P>0.05).Having multiple sexual partners(P<0.05) ,unfamiliar with sexual partners(P<0.05) ,having sex with network friends(P<0.05) ,no condom use in sexual life(P<0.01) ,having no regular HIV testing(P<0.01)were significantly related to HIV infection.Conclusion Reduc‐ing the sexual behavior among out‐of‐school adolescent MSM ,carrying out HIV counseling and testing ,promoting the use of condoms contribute to the reduction of HIV infection.

Objective: To analyze the influence of atmospheric particulate matters (PM_2.5 and PM₁₀) on low-birth-weight (LBW) infants at different periods of gestation. Methods: We conducted a systematic literature search for 2 471 articles related to particulate matter and LBW published from January 1st 2000 to January 1st 2016 using the PubMed, Cochrane Library, Web of Science, Science Direct, Chinese Web of Knowledge, Wanfang and Weipu, and the keywords were" air pollution" , "adverse birth outcomes" , "adverse pregnancy outcomes" , "low birth weight/LBW" . According to criteria, 27 literatures were selected and included. Metafor package of the R 3.1.1 Software was used to check the heterogeneity and merge the effect value of the selected literatures, and sensitivity analysis and publication bias were detected and adjusted. Results: A total of 2 471 studies selected form the databases, 27 enrolled in this analysis according to the inclusion and exclusion criteria. Each 10 μg/m³ increase in PM_2.5 was associated with combined OR values of 1st trimester, 2nd trimester, 3rd trimester and entire gestation at 1.02(95% CI: 0.87-1.19), 1.03 (95% CI: 0.91-1.16) , 1.07 (95%CI: 1.04-1.11) and 1.09 (95%CI: 1.04-1.15), respectively. And 10 μg/m³ increase in PM₁₀ was associated with combined OR values of 1st trimester, 2nd trimester, 3rd trimester and entire gestation at 1.66 (95%CI: 1.06-2.61), 1.58 (95%CI:1.28-1.95) , 1.38 (95%CI: 1.23-1.56) and 1.04 (95%CI: 0.99-1.09), respectively. After adjusting the bias of publication, each 10 μg/m³ increase in PM_2.5 was associated with the risk of low birth weight at 1.11 (95%CI: 1.02-1.21). Conclusion This meta analysis supports an adverse impact of maternal exposure to particulate air pollution on low birth weight, varying in effects by exposure period.