Objective To study the benchmark dose (BMD) of fluoride concentration in saliva,and to evaluate the significance of saliva fluoride on control and prevention of endemic fluorosis.Methods In September 2014,middle school students in endemic fluorosis areas and non-endemic fluorosis areas in North China Petoleum were selected as objects.The contents of fluoride in water,urine and saliva were determined.The correlation of fluoride content in water,urine fluoride and fluoride concentration in saliva was analyzed.According to the levels of the saliva fluoride concentration,the children were divided into 11 groups,＜ 1.00,1.00-,2.00-,3.00-,4.00-,5.00-,6.00-,7.00-,8.00-,9.00-and ≥ 10.00 mg/L.The prevalence of dental fluorosis and defected dental fluorosis were investigated and the saliva fluoride concentration was calculated by Banch-Mark Dose Software.Results Compared with non endemic areas,the fluoride contents in water,urine and saliva [(2.13 ± 0.13),(1.29 ±0.73),(4.01 ± 3.61) mg/L] were higher than that in endemic areas [(0.67 ± 0.13),(0.38 ± 0.08),(0.75 ± 0.12) mg/L,t =158.730,24.780,18.114,all P ＜ 0.01].The fluoride concentration in saliva was positively correlated with the fluoride content in water and urine in endemic areas (r =0.626,0.945,all P ＜ 0.01).The (BMDs and benchmark dose lower bound (BMDLs) were 0.91,0.54,3.72,3.32 mg/L respectively,calculated by Banch-Mark Dose Software.With the increase of fluoride concentration in saliva,the prevalence of dental fluorosis and defect dental fluorosis had increased too,especially when the fluoride content in saliva was more than 4 mg/L.There were significant doseresponse relationships between the urine fluoride and the prevalence of dental fluorosis and defected dental fluorosis.Conclusion The fluoride concentration in saliva could be used as one of the evaluation indexes of fluorosis,and the BMD of saliva fluoride concentration in endemic fluorosis areas is suggested as 0.91 mg/L.

Objective The purpose of this study was to study the correlation between dental fluorosis, saliva and plaque fluoride levels and urinary fluoride values in adolescents dental fluorosis. Methods A middle school was chosen as a survey point in the study. Two hundred adolescents were examined the degree of dental fluorosis by Dean's method. These adolescents were divided into four groups according to the severity of fluorosis (n = 52, 40, 28 and 80). Fluoride ion specific electrode was used to measure the fluoride levels in dental plaque, saliva, urinary and drinking water. The differences were analyzed b y ANOVA. Correlation of the fluoride levels between dental plaque, saliva, urine and the degree of dental fluorosis were analyzed by the method of multiple linear regression. Results The average fluoride content of drinking water was (2.20 ± 0.40) mg/L. Compared with controls, the fluoride concentrations in dental plaque, saliva and urine were higher in light, medium and severe dental fluorosis groups [(1.55 ± 0.88), (1.94 ± 0.77), (2.74 ± 0.83) than (0.32 ± 0.20) mg/L; (4.44 ± 1.62), (8.09 ± 0.93), (10.72 ± 0.99) than (0.02 ± 0.01) mg/L;(31.77 ± 6.09), (57.98 ± 1.83), (65.98 ± 2.78) than (13.06 ± 2.11) μg/g, all P<0.05]. Urinary fluoride was correlated with fluoride in saliva and dental plaque (r=0.245, 0.440, all P<0.05). Saliva fluoride was correlated with fluoride in dental plaque (r=0.849, P<0.01). The degree of dental fluorosis was correlated with fluoride in urine and saliva (r = 0.497, 0.896, 0.924, all P< 0.01). The multiple linear regression equation between fluoride in urine and the degree of dent al fluorosis, fluoride in dental plaque and saliva was as follow: y = 1.357 + 1.618x1 + 0.001x2 - 0.331x3 ± 0.69. Conclusions The metabolism of fluoride in body is related with oral fluoride repository in adolescents dental fluorosis. Fluoride in urine is influenced by plaque fluoride level, saliva fluoride concentration and the degree of dental fluorosis.

Catheter-associated bloodstream infection(CRBSI) is one of the most common hospital-associated infections, and the incidence of central line-associated blood stream Infections (CLABSI) is the highest in CRBSI. This paper analyzes the current monitoring system of CLABSI in China, and compares the concept and method of National Healthcare Safety Network (NHSN) monitoring system, in order to make suggestions for the CLABSI monitoring system in China, and further improve the quality of medical safety.

Objective:To analyze the effect of immersive scenario simulation training on improving the competency of infection prevention for health-care workers (HCWs).Methods:Taking the implementation time of immersive scenario simulation teaching training in Sir Run Run Shaw Hospital, Zhejiang University School of Medicine (August 2020) as the boundary, 352 new HCWs entered the hospital before the training (August 2019) were included as control group taking traditional teaching method, and 298 new HCWs entered the hospital after the training (August 2020) were included as observation group taking immersive scenario simulation combined with theoretical training. The mastery status of nosocomial infection-related knowledge and the implementation status of infection control measures (hand hygiene compliance, hand hygiene accuracy, correct personal protective equipment (PPE) selection, 100% of pass rate of PPE on and off, and qualified disposal of medical waste) were compared between the two groups of HCWs after theoretical teaching and different forms of practical training. The training effect (final assessment results) and training satisfaction (Minnesota satisfaction questionnaire, MSQ) of the two groups of HCWs were compared. SPSS 22.0 was used for t test and chi-square test. Results:The assessment results of the two groups of new HCWs trained by theoretical lecturing and immersive scenario simulation training were significantly improved compared with those just received theoretical lecturing, and the results of observation group were significantly higher than those of control group ( P<0.05). The implementation status of infection control measures after practical training were obviously improved in the two groups of HCWs compared to after theoretical lecturing, and the correct rates of PPE selection and all the procedure of donning and doffing PPE of observation group were significantly higher than those of control group ( P<0.05), but there were no significant differences in the hand hygiene accuracy and qualified disposal of medical waste between the two groups ( P>0.05). At the end of training, the final assessment results and satisfaction MSQ score of HCWs in observation group were significantly higher than those in control group ( P<0.05). Conclusion:Immersive scenario simulation teaching and training intervention is beneficial to improve the mastery of nosocomial infection knowledge of new HCWs, standardize their clinical infection control behaviors such as hand hygiene and aseptic operation, and finally obtain good training effect of infection prevention competency.

ObjectiveTo study the efficacy of community rehabilitation combined with drug therapy on rehabilitation of patients with schizophrenia in rural communities， and to provide references for community rehabilitation of patients with schizophrenia in rural areas of our country. MethodA total of 81 patients in rural communities of three towns in Lanzhou new area who met the diagnostic criteria of International Classification of Diseases， tenth edition （ICD-10） were randomly divided into study group （n=39） and control group （n=42）. Both groups received general drug treatment. On this basis， the study group received community rehabilitation intervention for 6 months. Before and after intervention， Positive and Negative Syndrome Scale （PANSS）， Activity of Daily Living Scale （ADL）， Social Disability Screening Schedule （SDSS） and Schizophrenia Quality of Life Scale （SQLS） were used to assess the psychotic symptoms， social function and quality of life in two groups. ResultsAfter intervention， the PANSS total score ［（55.54±14.75） vs. （63.52±13.95）， t=-2.504， P=0.014］， negative symptom factor score ［（15.64±4.50） vs. （18.38±5.13）， t=-2.547， P=0.013］ and general psychopathological factor score ［（25.67±7.39） vs. （30.35±6.60）， t=-3.015， P=0.003］ of the study group were lower than those of the control group. The SDSS score ［（8.21±3.78） vs. （10.21±4.67）， t=-2.118， P=0.037］ and SQLS score ［（18.97±6.23） vs. （22.43±8.04）， t=2.150， P=0.035］ of the study group were lower than those of the control group. ConclusionCommunity rehabilitation combined with drug therapy may help alleviate psychotic symptoms， improve social function and improve quality of life in patients with schizophrenia in rural communities.

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) has become one major threat to human population health. The RNA-dependent RNA polymerase (RdRp) presents an ideal target of antivirals, whereas nucleoside analogs inhibitor is hindered by the proofreading activity of coronavirus. Herein, we report that corilagin (RAI-S-37) as a non-nucleoside inhibitor of SARS-CoV-2 RdRp, binds directly to RdRp, effectively inhibits the polymerase activity in both cell-free and cell-based assays, fully resists the proofreading activity and potently inhibits SARS-CoV-2 infection with a low 50% effective concentration (EC