Objective To explore the characteristics of respiratory tract microbiota and its clinical significance in children with protracted bacterial bronchitis (PBB).Methods Twelve children aged from 5 months to 2 years old with PBB (PBB group) and 12 age-matched tracheomalacia(TM) children (TM group) were included in this study,who were admitted into the Respiratory Department of Shenzhen Children's Hospital.Their bronchoalveolar lavage fluid (BALF) samples were collected.Bacterial DNA was extracted from their BALF samples and the 16S rRNA V3-V4 region was sequenced by using Illumina MiSeq TMII system,and the findings were analyzed by bioinformatics methods.Results Principal component analysis revealed the difference in microbiota composition between 2 groups.Compared with TM group,PBB group exhibited lower microbial diversity:the Shannon indices were also 1.683 ± 0.703 and 2.324 ± 0.142 for PBB group and TM group respectively,and the differences were also significant(all P ＜ 0.05),and the Simpson indices were 0.416 ± 0.216 and 0.191 ± 0.025 for PBB group and TM group,respectively,and the differences were also significant (all P ＜ 0.05).The relative abundance of Actinobacteria was significantly lower in PBB group [(0.215 ± 0.228) ％] than that in TM group [(3.028 ± 0.592) ％] (P ＜ 0.01).The proportions of beneficial genera obviously decreased in PBB group,including Lactococcus [(13.464±7.319)％ in PBB group,and (44.784 ± 5.020)％ in TM group,P ＜0.01],Lactobacillus [(0.153 ±0.076)％ in PBB group,and (0.313 ±0.060)％ in TM group,P＜0.01],andArthrobacter [(0.024 ±0.018)％ in PBB group,and (2.970 ±0.584)％ in TM group,P＜0.01].On the other hand,the relative abundances of opportunistic pathogenic genera increased in PBB group significantly,including Haemophilus [(14.319 ± 29.532) ％ in PBB group,and (0.047 ± 0.127) ％ in TM group,P ＜ 0.Ol],Pseudomonas [(10.406 ± 25.439) ％ in PBB group,and (7.228 ± 0.948) ％ in TM group,P ＜ 0.01],and Escherichia [(0.432 ±0.441)％ in PBB group,and (0.055 ±0.035)％ in TM group,P ＜0.01].Conclusion These findings confirmed the existence of respiratory tract microbiotia dysbiosis in PBB,which probably was one of the pathogenetic mechanisms for PBB.

Objective : To study the epidemiological characteristics of coronavirus disease 2019 （COVID-19） in Zhoushan, so as to provide reference for improving the prevention and control capability of COVID-19. Methods : All the confirmed cases of COVID-19 in Zhoushan, diagnosed according to China’s “COVID-19 diagnosis and treatment plan （fifth version） ” and reported from January 19 to February 17, 2020, were extracted from the infectious disease surveillance system. Data of general information, clinical characteristics, laboratory Results, transmission and detection routes were collected and analyzed. Results : By February 17, Ten confirmed cases of COVID-19 in Zhoushan had been reported, including 7 males and 3 females. They were all adults, with an average age of （50.90±15.00） years. Five cases were discharged. The incubation period ranged from 2 to 12 days, with a median of 5 days. The first symptoms were fever （8 cases）, cough （7 cases） and muscle pain （2 cases）. Chest computed tomographic （CT） scans showed ground glass opacities in the lungs of all the cases. Six cases had Wuhan related exposure. SARS-CoV-2 was tested positive in the sputum specimens or throat swabs of all the cases and the faeces of 4 cases. The last suspicious exposure of 5 cases occurred before, and that of another 5 cases occurred after the onset of clinical symptoms in the confirmed maternal cases. Three cases were found in active consultation after clinical symptoms, and another 7 cases were found in the monitoring of close contacts. Conclusions The 10 confirmed cases of COVID-19 reported in Zhoushan are all adults, and most have Wuhan related exposure. SARS-CoV-2 can be detected in the fecal samples, but the existence of fecal-oral transmission needs more research. SARS-CoV-2 has strong infectivity, and may also have infectivity before the onset of symptoms （at the end of incubation period）. Isolation and early detection of close contacts are conducive for early case-finding.

Objective:To investigate the early clinical effects of home-based mobile health intervention on knee joint function after anterior cruciate ligament (ACL) reconstruction.Methods:This was a prospective randomized controlled trial. Patients undergoing arthroscopic ACL reconstruction alone at the Institute of Sports Medicine, Peking University Third Hospital from April 2019 to December 2019 were elected in the trial. Patients were divided into the intervention group and the control group according to random number method. The control group only received the guidance of the traditional paper rehabilitation schedule, while the intervention group also received personalized guidance of electronic rehabilitation prescription and follow-up notice delivered by a WeChat Mini Program Rehabilitation Cloud Platform in addition to the traditional guidance. Joint range of motion (ROM), visual analogue scale (VAS) and thigh circumference difference were assessed before and after the operation. Independent sample t test or Mann-Whitney U test was used for comparison of data between groups, and chi-square test was used for comparison of enumeration data. Results:One hundred and twenty five patients were enrolled in the trial, including 99 males and 26 females, with an average age of 29.0 years (range:18 to 45 years) and an average body mass index of 24.8 kg/m 2 (range:15.8 to 36.6 kg/m 2). At 6 weeks, follow-up was available in 106 cases the target-reach rate of ROM in control group was 42.6%(23/54), which was 67.3%(35/52) in the intervention group, the difference was statistically significant (χ 2=6.53, P=0.01); VAS of the intervention group was 2.5(2.0), lower than that of the control group 3.0(2.0)( M( Q R)), the difference was statistically significant ( Z=-2.06, P=0.04); And the thigh circumference difference of the intervention group was 2.0(2.0)cm lower than that of the control group 3.0(1.8)cm, the difference was statistically significant ( Z=-3.00, P<0.01). Conclusion:Mobile health intervention can improve the early postoperative rehabilitation effect after ACL construction and the ROM of the knee joint, and reduce the bent-knee pain along with the thigh circumference difference.

Objective:To investigate the early clinical effects of home-based mobile health intervention on knee joint function after anterior cruciate ligament (ACL) reconstruction.Methods:This was a prospective randomized controlled trial. Patients undergoing arthroscopic ACL reconstruction alone at the Institute of Sports Medicine, Peking University Third Hospital from April 2019 to December 2019 were elected in the trial. Patients were divided into the intervention group and the control group according to random number method. The control group only received the guidance of the traditional paper rehabilitation schedule, while the intervention group also received personalized guidance of electronic rehabilitation prescription and follow-up notice delivered by a WeChat Mini Program Rehabilitation Cloud Platform in addition to the traditional guidance. Joint range of motion (ROM), visual analogue scale (VAS) and thigh circumference difference were assessed before and after the operation. Independent sample t test or Mann-Whitney U test was used for comparison of data between groups, and chi-square test was used for comparison of enumeration data. Results:One hundred and twenty five patients were enrolled in the trial, including 99 males and 26 females, with an average age of 29.0 years (range:18 to 45 years) and an average body mass index of 24.8 kg/m 2 (range:15.8 to 36.6 kg/m 2). At 6 weeks, follow-up was available in 106 cases the target-reach rate of ROM in control group was 42.6%(23/54), which was 67.3%(35/52) in the intervention group, the difference was statistically significant (χ 2=6.53, P=0.01); VAS of the intervention group was 2.5(2.0), lower than that of the control group 3.0(2.0)( M( Q R)), the difference was statistically significant ( Z=-2.06, P=0.04); And the thigh circumference difference of the intervention group was 2.0(2.0)cm lower than that of the control group 3.0(1.8)cm, the difference was statistically significant ( Z=-3.00, P<0.01). Conclusion:Mobile health intervention can improve the early postoperative rehabilitation effect after ACL construction and the ROM of the knee joint, and reduce the bent-knee pain along with the thigh circumference difference.

Objective To analyze the application value of cervical vascular color Doppler ultrasound com-bined with serum microRNA-222-3p(miR-222-3p)and microRNA-206(miR-206)in the diagnosis of carotid artery stenosis in patients with cerebral infarction.Methods A total of 90 patients with cerebral infarction ad-mitted to this hospital from July 2018 to July 2022 were selected as the study group,and were divided into mild stenosis group(29 cases),moderate stenosis group(35 cases),and severe stenosis group(26 cases)ac-cording to the degree of carotid artery stenosis.In addition,96 healthy people who underwent physical exami-nation in the hospital were selected as the control group.Real-time fluorescence quantitative PCR was used to detect the levels of serum miR-222-3p and miR-206 in each group.All patients with cerebral infarction under-went cervical vascular color Doppler ultrasound examination,and the clinical data of patients with different de-grees of stenosis were analyzed.Multivariate Logistic regression was used to analyze the factors affecting the degree of carotid artery stenosis in patients with cerebral infarction.The receiver operating characteristic(ROC)curve was used to evaluate the diagnostic value of carotid ultrasound indicators,serum miR-222-3p and miR-206 levels for the degree of carotid artery stenosis in patients with cerebral infarction.Results Compared with the control group,the study group had a significant increase in the serum level of miR-222-3p and a sig-nificant reduction in the serum level of miR-206(P＜0.05).Compared with the mild stenosis group,the peak systolic velocity(PSV),end diastolic volume(EDV)and serum miR-222-3p level were increased,and the ser-um miR-206 level was decreased in the moderate stenosis group and the severe stenosis group(P＜0.05).Compared with moderate stenosis group,EVD,PSV and serum miR-222-3p levels were significantly in-creased,and miR-206 level was decreased in severe stenosis group(P＜0.05).EVD,PSV,serum miR-222-3p level were risk factors for carotid artery stenosis in patients with cerebral infarction,and serum miR-206 level was a protective factor for carotid artery stenosis in patients with cerebral infarction(P＜0.05).The area un-der the curve of EVD,PSV combined with serum miR-222-3p and miR-206 in diagnosing the degree of carotid artery stenosis in patients with cerebral infarction was 0.991,and the sensitivity and specificity were 98.36％and 93.10％,respectively.It was better than that of EVD,PSV,serum miR-222-3p,and miR-206 alone(Zcombination-EVD=2.927,P=0.003,Z combination-PSV=2.834,P=0.005,Zcombination-miR-222-3p=3.300,P=0.001,Zcombination-miR-206=3.730,P＜0.001).Conclusion Cervical vascular color Doppler ultrasound combined with ser-um miR-222-3p and miR-206 has application value in the diagnosis of carotid artery stenosis in patients with cerebral infarction.

Objective: To analyze the influencing factors and mechanism for unprotected sexual behavior of men who have sex with men (MSM) in China. Methods: MSM who are more than 16 years old and have had homosexual sexual behaviors in recent years were recruited from five cities (Tianjin, Harbin, Nanjing, Chongqing and Xi'an) with active MSM population during 2013-2014 through network, site recruitment and peer recommendation using convenient sampling method. 3 519 subjects were included in this study. The sexual behavior related information of MSM in five cities was investigated using questionnaires. The confirmatory factor analysis was used to construct the measurement model by using the robust estimation method based on the weighted least square method to estimate parameters, and the final model was determined through evaluation and modification. Results: A total of 3 519 subjects were (29.9±8.76) years old, with a clear sexual orientation of 3 223 (91.6%), and 2 287 (65.0%) were aware of free HIV/AIDS treatment policies. The proportion of using condom last time was 77.2% (n=2 718), and the proportion of using condom every time was 36.9% (n=1 299) and 43.2% (n=1 521) respectively for the past six months with fixed and temporary partners. Structural equation model provided a good fit, the root mean square error of approximation, comparative fit index and non-normed fit index was 0.07, 0.97, 0.95, respectively. Knowing AIDS knowledge, educational level and sexual orientation had direct effects on unprotected sexual behavior, and the path coefficients were 0.179,-0.049 and -0.159, respectively. While the role of interventions was indirect, the path coefficient was 0.147. Conclusion Lower education and unclear sexual orientation are disadvantages for reducing unprotected sexual behavior. Interventions mainly affect the unprotected sexual behavior by improving the level of HIV/AIDS knowledge. Increasing the comprehensive knowledge of MSM through intervention should be highly valued.