Objective: To investigate the risk factors of road traffic injuries caused by electric bicycles, so as to provide insights into the prevention and control of road traffic injuries. Methods: A case-control study was performed (cases to controls ratio of 1∶2). The riders of electric bicycles with road-traffic injuries in Songjiang District, Shanghai Municipality during the period between June 2020 and May 2021 were included in the case group, and age-, gender- and occupation-matched riders of electric bicycles without road-traffic injuries in the same study area during the same study period served as controls. Participants' demographic data, living habits, health status, awareness of safe riding and riding behaviors were collected using questionnaire surveys, and the risk factors of road-traffic injuries caused by electric bicycles were identified using a multivariable conditional logistic regression model. Results: There were 167 participants in the case group, including 122 men (73.05%) and with an age of 38 (21) years, and 334 participants in the control group, including 244 men (73.05%) and with an age of 32 (18) years. Multivariable conditional logistic regression analysis identified sleep duration of less than 8 h (OR=1.760, 95%CI: 1.111-2.786), occasional/frequent anxiety (OR=5.140, 95%CI: 1.067-24.750), unawareness of riding speed limit of 25 km/h (OR=2.352, 95%CI: 1.460-3.788), having been warned or punished for violating traffic rules (OR=2.246, 95%CI: 1.243-4.060), running a red light (OR=1.725, 95%CI: 1.043-2.852), riding speed of ≥ 30 km/h (sometimes, OR=2.409, 95%CI: 1.475-3.933; often, OR=4.711, 95%CI: 2.153-10.309) as risk factors of electric bicycle road-traffic injuries. Conclusions Electric bicycle road-traffic injuries is associated with sleep duration, anxiety, awareness of traffic rules, and unsafe riding behaviors. Traffic safety education and law enforcement is required to be reinforced among riders of electric bicycles.

Objective To evaluate the feasibility of repair of full-thickness skin defects in nude mice with tissue-engineered skin which was constructed by culture of human amniotic epithelial cells (hAECs) and fibroblasts on human de-epidermized dermis (DED).Methods Healthy human amniotic tissues were treated with trypsin at a low concentration in multi-steps to prepare hAECs,and a two-step collagenase digestion was used to treat healthy children's prepuce tissues to prepare fibroblast suspensions.When fibroblasts were cultured in vitro up to passage 3-5 and hAECs up to passage 2,they were seeded on the reticular dermal surface and basement membrane surface of the DED respectively to construct the tissueengineered skin.A total of 20 heahhy male nude mice aged 3-4 weeks were enrolled into this experiment,and full-thickness skin defects were made on the middle of the back of mice.Then,these mice were randomly divided into 2 groups by using a lottery method,and reconstructed full-thickness tissueengineered skin grafts and vaseline oil gauze were used to cover the wounds in the tissue-engineered skin group and control group respectively.The whole body and transplantation sites of the nude mice were observed on day 7,14,21 and 28 after transplantation,the wound healing time and rate were compared between the above two groups,and skin tissues at the transplantation site were harvested at 4 weeks after transplantation and subjected to histological examination.Results HAECs had stem-cell characteristics and expressed octamer-binding protein-4 (OCT-4) and embryonic marker stage-specific embryonic antigen4 (SSEA-4).After 2-week organ culture,the in vitro reconstructed tissue-engineered skin showed 4-9 continuous layers of stratified epithelium,and the histological structure of the epidermis was similar to that of the normal human skin.Compared with the control group,the tissue-engineered skin group showed significantly higher wound healing rates on day 7,14 and 21 after transplantation (57.49％ ± 6.11％ vs.22.93％ ± 4.26％,92.80％ ± 3.10％ vs.54.57％ ± 7.94％,98.83％ ± 0.25％ vs.91.16％ ± 4.79％,respectively;n =10,t =27.36,32.23,11.80,respectively,all P ＜ 0.001),shorter wound healing time [(21.51 ± 1.51) d vs.(28.80 ± 1.14) d,n =10,t =42.23,P ＜ 0.001],with the color of skin grafts closer to that of autologous skin on day 28 after transplantation.Histological examination revealed distinct stratification of the epithelium,obvious keratinization and favorable growth of cells in the dermis in the tissue-engineered skin group,but thin epithelium with some defects,indistinct stratification of the dermis,and inflammatory cell infiltration in the control group.Condusion Tissue-engineered skin constructed by the culture of hAECs and fibroblasts on human DED can survive in nude mice after transplantation,resulting in a more favorable healing of wounds,and is expected to serve as a kind of ideal tissue-engineered skin.

uate and should be standardized.

Objective:To understand the 10-year risk of ischemic cardiovascular disease (ICVD) in hypertensive patients in communities in Shenzhen, and to provide baseline data for the comprehensive implementation of community-based hypertension health management measures based on ICVD risk assessment.Methods:From July 2017 to June 2018, 200 community health service centers in 10 districts of Shenzhen were selected by multi-stage random sampling to investigate hypertensive patients in communities aged≥35. After the patients who met the inclusion criteria signed the informed consent form, the demographic characteristics, physical examination, and laboratory tests were conducted. The absolute risk of ICVD in 10 years was evaluated by using the ICVD risk assessment module from the Shenzhen community health service information system. According to the China 10-year risk for ICVD score tables, recommended by the Chinese cardiovascular disease prevention guidelines, the risk grade of ICVD was estimated and analyzed. In addition, the relative risk was used to eliminate the influence of gender and age, and the single sample t-test was used for comparisons with the larger population. Results:30 015 hypertensive patients from communities were investigated, including 16 165 (53.86%) males and 13 850 (46.14%) females, aged 35-102 years, with a median age of 59.0. 6 405 (21.34%), 5 771 (19.23%) and 17 839 (59.43%) were at high, medium and low risk of ICVD, respectively. The absolute risk was 3.77%, 95% CI (3.72%-3.82%). The risk grades of ICVD in 10 years was different as per gender, age, marital status, population type， smoking, family history of hypertension, history of diabetes mellitus, systolic blood pressure, body mass index, and total cholesterol level, P values were all<0.001. The risk grades of ICVD in males, married patients, floating populations, having a total cholesterol <5.20 mmol/L, non-smokers, non-diabetics, and having a family history of hypertension were lower than that of other characteristics, and increased with age, systolic blood pressure, and body mass index. Further analysis of 15 652 patients aged 35-59 years old showed that the 10-year risk of ICVD in patients with hypertension in communities was slightly higher than that of the larger population, and the relative risk was 1.27, 95% CI (1.25-1.28), t=37.648, P<0.001. In males, relative risk was 0.94, 95% CI (0.93-0.95), t= 9.906, P<0.001, and there were no significant trend changes among age groups. In females, relative risk was 2.05, 95% CI (2.01-2.09), t=72.207, P<0.001, and increased with age. Conclusion:The 10-year risk of ICVD in hypertensive patients is often at a high level in Shenzhen, so it is necessary to carry out the risk assessment of ICVD in the community. The effect of community hypertension health management on reducing the risk of ICVD may vary between genders. The risk of ICVD in male patients is lower than that of males in the larger population, but in female patients it is still much higher.

Objective : To study the protective effect of polydatin on lipopolysaccharide-induced injury of human umbilical vein vascular endothelial cells (HUVECs) through the protein Janus kinase 2 (JAK2) / signal transducers and activators of transcription 3 ( STAT3) signaling pathway． Methods : HUVECs were cultured in vitro，and 500 ng / ml LPS induced their injury and set as a model group ; based on the model group，endothelial cells were intervened with different concentrations ( 10，20，and 40 μmol / L ) of polydatin for 24 h，and set as polydatin low concentration group，polydatin medium concentration group，and polydatin high concentration group，respectively ; a control group was set as another group．CCK-8，monocyte-endothelial cell adhesion，scratch and Transwell assays were used to detect cell viability，adhesion，migration and invasive ability ; ELISA was used to detect interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-α) levels in the cell supernatant ; Western blot was used to detect the expression of proteins related to the JAK2 / STAT3 signaling pathway levels of JAK2 / STAT3 signaling pathway relat- ed proteins. Results : Compared with the control group，the model group showed decreased cell survival ( P < 0. 01) ，increased cell adhesion，migration and invasion (P＜0. 001，P ＜0. 05，P ＜0. 01) ，increased levels of IL-6 and TNF-α in the cell supernatant (P＜0. 001) ，and increased levels of phosphorylation of JAK2 and STAT3 pro- teins in the cells (P＜0. 05) ．Compared with the model group，LPS damage to cells was attenuated after polydatin intervention，cell survival was increased in polydatin low －，medium － and high － concentration groups ( P < 0. 05) ，cell adhesion，migration，and invasion decreased (P＜0. 05，P＜0. 05，P＜0. 001) ，IL-6 and TNF-α levels in cell supernatants decreased (P＜0. 05) ，and the levels of cellular JAK2 and STAT3 protein phosphorylation lev- els decreased (P＜0. 05) ． Conclusion Polydatin seems to reduce the inflammatory injury of human umbilical vein endothelial cells induced by LPS，reducing the secretion of inflammatory factors，and inhibiting the ability of cell ad- hesion，migration and invasion，which may be related to the down-regulation of JAK2 / STAT3 signal pathway by polydatin.

Objective: To understand the possible transmission route of a family cluster of COVID-19 in Zhengzhou and the potential infectivity of COVID-19 in incubation period, and provide scientific evidence for the timely control of infectious source and curb the spread of the epidemic. Methods: Epidemiological investigation was conducted for a family cluster of COVID-19 (8 cases) with descriptive epidemiological method, and respiratory tract samples of the cases were collected for the nucleic acid detection of 2019-nCoV by RT-PCR. Results: Two primary cases, which occurred on 31 January and 1 February, 2020, respectively, had a common exposure history in Wuhan. The other six family members had onsets on 30 January, 31 January, 1 February (three cases) and 3 February, 2020. Conclusions In this family cluster of COVID-19, six family members were infected through common family exposure to the 2 primary cases. Five secondary cases had onsets earlier than or on the same day as the primary cases, indicating that COVID-19 is contagious in incubation period, and the home isolation in the early phase of the epidemic might lead to the risk of family cluster of COVID-19.

Objective:To investigate the epidemiological characteristics, diagnosis, treat-ment and prognosis of gallbladder cancer in China from 2010 to 2017.Methods:The single disease retrospective registration cohort study was conducted. Based on the concept of the real world study, the clinicopathological data, from multicenter retrospective clinical data database of gallbladder cancer of Chinese Research Group of Gallbladder Cancer (CRGGC), of 6 159 patients with gallbladder cancer who were admitted to 42 hospitals from January 2010 to December 2017 were collected. Observation indicators: (1) case resources; (2) age and sex distribution; (3) diagnosis; (4) surgical treatment and prognosis; (5) multimodality therapy and prognosis. The follow-up data of the 42 hospitals were collected and analyzed by the CRGGC. The main outcome indicator was the overall survival time from date of operation for surgical patients or date of diagnosis for non-surgical patients to the end of outcome event or the last follow-up. Measurement data with normal distribu-tion were represented as Mean±SD, and comparison between groups was conducted using the t test. Measurement data with skewed distribution were represented as M( Q1, Q3) or M(range), and com-parison between groups was conducted using the U test. Count data were described as absolute numbers or percentages, and comparison between groups was conducted using the chi-square test. Univariate analysis was performed using the Logistic forced regression model, and variables with P<0.1 in the univariate analysis were included for multivariate analysis. Multivariate analysis was performed using the Logistic stepwise regression model. The life table method was used to calculate survival rates and the Kaplan-Meier method was used to draw survival curves. Log-rank test was used for survival analysis. Results:(1) Case resources: of the 42 hospitals, there were 35 class A of tertiary hospitals and 7 class B of tertiary hospitals, 16 hospitals with high admission of gallbladder cancer and 26 hospitals with low admission of gallbladder cancer, respectively. Geographical distribution of the 42 hospitals: there were 9 hospitals in central China, 5 hospitals in northeast China, 22 hospitals in eastern China and 6 hospitals in western China. Geographical distribution of the 6 159 patients: there were 2 154 cases(34.973%) from central China, 705 cases(11.447%) from northeast China, 1 969 cases(31.969%) from eastern China and 1 331 cases(21.611%) from western China. The total average number of cases undergoing diagnosis and treatment in hospitals of the 6 159 patients was 18.3±4.5 per year, in which the average number of cases undergoing diagnosis and treatment in hospitals of 4 974 patients(80.760%) from hospitals with high admission of gallbladder cancer was 38.8±8.9 per year and the average number of cases undergoing diagnosis and treatment in hospitals of 1 185 patients(19.240%) from hospitals with low admission of gallbladder cancer was 5.7±1.9 per year. (2) Age and sex distribution: the age of 6 159 patients diagnosed as gallbladder cancer was 64(56,71) years, in which the age of 2 247 male patients(36.483%) diagnosed as gallbladder cancer was 64(58,71)years and the age of 3 912 female patients(63.517%) diagnosed as gallbladder cancer was 63(55,71)years. The sex ratio of female to male was 1.74:1. Of 6 159 patients, 3 886 cases(63.095%) were diagnosed as gallbladder cancer at 56 to 75 years old. There was a significant difference on age at diagnosis between male and female patients ( Z=-3.99, P<0.001). (3) Diagnosis: of 6 159 patients, 2 503 cases(40.640%) were initially diagnosed as gallbladder cancer and 3 656 cases(59.360%) were initially diagnosed as non-gallbladder cancer. There were 2 110 patients(34.259%) not undergoing surgical treatment, of which 200 cases(9.479%) were initially diagnosed as gallbladder cancer and 1 910 cases(90.521%) were initially diagnosed as non-gallbladder cancer. There were 4 049 patients(65.741%) undergoing surgical treatment, of which 2 303 cases(56.878%) were initially diagnosed as gallbladder cancer and 1 746 cases(43.122%) were initial diagnosed as non-gallbladder cancer. Of the 1 746 patients who were initially diagnosed as non-gallbladder cancer, there were 774 cases(19.116%) diagnosed as gallbladder cancer during operation and 972 cases(24.006%) diagnosed as gallbladder cancer after operation. Of 6 159 patients, there were 2 521 cases(40.932%), 2 335 cases(37.912%) and 1 114 cases(18.087%) undergoing ultrasound, computed tomography (CT) or magnetic resonance imaging (MRI) examination before initial diagnosis, respec-tively, and there were 3 259 cases(52.914%), 3 172 cases(51.502%) and 4 016 cases(65.205%) undergoing serum carcinoembryonic antigen, CA19-9 or CA125 examination before initially diagnosis, respectively. One patient may underwent multiple examinations. Results of univariate analysis showed that geographical distribution of hospitals (eastern China or western China), age ≥72 years, gallbladder cancer annual admission of hospitals, whether undergoing ultrasound, CT, MRI, serum carcinoembryonic antigen, CA19-9 or CA125 examination before initially diagnosis were related factors influencing initial diagnosis of gallbladder cancer patients ( odds ratio=1.45, 1.98, 0.69, 0.68, 2.43, 0.41, 1.63, 0.41, 0.39, 0.42, 95% confidence interval as 1.21-1.74, 1.64-2.40, 0.59-0.80, 0.60-0.78, 2.19-2.70, 0.37-0.45, 1.43-1.86, 0.37-0.45, 0.35-0.43, 0.38-0.47, P<0.05). Results of multivariate analysis showed that geographical distribution of hospitals (eastern China or western China), sex, age ≥72 years, gallbladder cancer annual admission of hospitals and cases undergoing ultrasound, CT, serum CA19-9 examination before initially diagnosis were indepen-dent influencing factors influencing initial diagnosis of gallbladder cancer patients ( odds ratio=1.36, 1.42, 0.89, 0.67, 1.85, 1.56, 1.57, 0.39, 95% confidence interval as 1.13-1.64, 1.16-1.73, 0.79-0.99, 0.57-0.78, 1.60-2.14, 1.38-1.77, 1.38-1.79, 0.35-0.43, P<0.05). (4) Surgical treatment and prognosis. Of the 4 049 patients undergoing surgical treatment, there were 2 447 cases(60.435%) with complete pathological staging data and follow-up data. Cases with pathological staging as stage 0, stage Ⅰ, stage Ⅱ, stage Ⅲa, stage Ⅲb, stage Ⅳa and stage Ⅳb were 85(3.474%), 201(8.214%), 71(2.902%), 890(36.371%), 382(15.611%), 33(1.348%) and 785(32.080%), respectively. The median follow-up time and median postoperative overall survival time of the 2 447 cases were 55.75 months (95% confidence interval as 52.78-58.35) and 23.46 months (95% confidence interval as 21.23-25.71), respectively. There was a significant difference in the overall survival between cases with pathological staging as stage 0, stage Ⅰ, stage Ⅱ, stage Ⅲa, stage Ⅲb, stage Ⅳa and stage Ⅳb ( χ2=512.47, P<0.001). Of the 4 049 patients undergoing surgical treatment, there were 2 988 cases(73.796%) with resectable tumor, 177 cases(4.371%) with unresectable tumor and 884 cases(21.833%) with tumor unassessable for resectabi-lity. Of the 2 988 cases with resectable tumor, there were 2 036 cases(68.139%) undergoing radical resection, 504 cases(16.867%) undergoing non-radical resection and 448 cases(14.994%) with operation unassessable for curative effect. Of the 2 447 cases with complete pathological staging data and follow-up data who underwent surgical treatment, there were 53 cases(2.166%) with unresectable tumor, 300 cases(12.260%) with resectable tumor and receiving non-radical resection, 1 441 cases(58.888%) with resectable tumor and receiving radical resection, 653 cases(26.686%) with resectable tumor and receiving operation unassessable for curative effect. There were 733 cases not undergoing surgical treatment with complete pathological staging data and follow-up data. There was a significant difference in the overall survival between cases not undergoing surgical treatment, cases undergoing surgical treatment for unresectable tumor, cases undergoing non-radical resection for resectable tumor and cases undergoing radical resection for resectable tumor ( χ2=121.04, P<0.001). (5) Multimodality therapy and prognosis: of 6 159 patients, there were 541 cases(8.784%) under-going postoperative adjuvant chemotherapy and advanced chemotherapy, 76 cases(1.234%) under-going radiotherapy. There were 1 170 advanced gallbladder cancer (pathological staging ≥stage Ⅲa) patients undergoing radical resection, including 126 cases(10.769%) with post-operative adjuvant chemotherapy and 1 044 cases(89.231%) without postoperative adjuvant chemo-therapy. There was no significant difference in the overall survival between cases with post-operative adjuvant chemotherapy and cases without postoperative adjuvant chemotherapy ( χ2=0.23, P=0.629). There were 658 patients with pathological staging as stage Ⅲa who underwent radical resection, including 66 cases(10.030%) with postoperative adjuvant chemotherapy and 592 cases(89.970%) without postoperative adjuvant chemotherapy. There was no significant difference in the overall survival between cases with postoperative adjuvant chemotherapy and cases without postoperative adjuvant chemotherapy ( χ2=0.05, P=0.817). There were 512 patients with pathological staging ≥stage Ⅲb who underwent radical resection, including 60 cases(11.719%) with postoperative adjuvant chemotherapy and 452 cases(88.281%) without postoperative adjuvant chemotherapy. There was no significant difference in the overall survival between cases with postoperative adjuvant chemo-therapy and cases without post-operative adjuvant chemo-therapy ( χ2=1.50, P=0.220). Conclusions:There are more women than men with gallbladder cancer in China and more than half of patients are diagnosed at the age of 56 to 75 years. Cases undergoing ultrasound, CT, serum CA19-9 examination before initial diagnosis are independent influencing factors influencing initial diagnosis of gallbladder cancer patients. Preoperative resectability evaluation can improve the therapy strategy and patient prognosis. Adjuvant chemotherapy for gallbladder cancer is not standardized and in low proportion in China.