AIM:To establish a method for simultaneously determining luteolin and negletein in Mosla chinensis Maxium collected in picking times.METHODS:The Angilent Zorbax,Extend C-18 column(4.6 mm?250 mm,5 ?m)was used with methanol-water(containing 0.4% phosphonic acid)(50 ∶50)as mobile phase.The flow rate was 1.0 mL/min.The detection wavelength was set at 350 nm.RESULTS:The method had the good linear relationship within the range of 0.04-0.61 ?g for luteolin and within the range of 0.20-3.01 ?g for negletein,respectively,with the correlation coefficient of 0.999 9.The average recoveries of the two flavones were 97.32%,98.60%,respectively.The contents of luteolin and negletein in Mosla chinensis Maxium.varied in different picking times,which reached the its maximum at florescence(264.8 ?g/g,2 746.3 ?g/g)in August,respectively.CONCLUSION:The method is fast,rapid,convenient,accurate and can be used for quality control of Mosla chinensis Maxium.

AIM:To establish a method for simultaneously determining luteolin and negletein in Mosla chinensis Maxium collected in picking times.METHODS: The Angilent Zorbax,Extend C-18 column(4.6 mm×250 mm,5μm) was used with methanol-water (containing 0.4% phosphonic acid)(50: 50) as mobile phase.The flow rate was 1.0 mL/min.The detection wavelength was set at 350 nm.RESULTS : The method had the good linear relationship within the range of 0.04-0.61 μg for luteolin and within the range of 0.20-3.01 μg for negletein,respectively,with the correlation coefficient of 0.999 9.The average recoveries of the two flavones were 97.32%,98.60%,respectively.The contents of luteolin and negletein in Mosla chinensis Maxium.varied in different picking times,which reached the its maximum at florescence (264.8 μg/g,2 746.3 μg/g) in August,respectively.CONCLUSION: The method is fast,rapid,convenient,accurate and can be used for quality control of Mosla chinensis Maxium.

Objective To investigate and analysis the epidemiological characteristics of a cluster epidemic of COIVD-19 in a collective workplace in Tianjin, evduate the prevention and control measures based on limited evidence and experience in early period of COVID-19 epidemic. Methods Descriptive research method was used to describe the distribution and other epidemiological characteristics of the cluster cases of COVID-19. Results Since the onset of the first index case on January 15, ten confirmed COVID-19 cases had occurred in the workplace, and the epidemic had spread from the workplace to 4 families, infecting 7 family members. The median age of 17 cases was 55 (19-79) years. All the 10 employee cases were males, and in 7 family cases, 3 were males and 4 were females. Of the employee cases, 8 worked in CW workshop and 2 worked in administrative office building. The median exposure-onset interval of all the cases was 4 (0-12) days, and the median exposure-onset interval was 4.5 days in the employee cases and 4 days in the family cases. The median onset-medical care seeking interval was 4 days in the non-isolated cases, 2.5 days in the cases with home isolation after onset, and 0.5 day in the cases with home isolation before onset. Conclusion The clustering of COVID-19 cases was observed in this workplace in Tianjin, which affected 4 families. In the early stage of the epidemic, accurate and rapid blocking and control measures can completely prevent the large-scale spread of COVID-19.