Objective: To understand the epidemiological characteristics of viral hepatitis B in Shaoxing from 2008 to 2018,so as to provide basis for formulating the viral hepatitis B prevention and control strategy. Methods: The data of viral hepatitis B cases in Shaoxing from 2008 to 2018 were collected from infectious diseases reporting and management system. Descriptive epidemiological method was employed to analyze the time,place and population characteristics of viral hepatitis B cases in Shaoxing. Annual percentage change（APC）was calculated to analyze the development trend of viral hepatitis B. Results : From 2008 to 2018,a total of 22 764 cases of viral hepatitis B were reported in Shaoxing,with an average annual incidence rate of 42.24/100 000 and a standardized incidence rate of 39.19/100 000. The incidence rate of viral hepatitis B decreased from 2008 to 2018,among which the APC from 2012 to 2018 was -18.00% with a significantly downward trend（P<0.05）. Six counties,cities or districts in Shaoxing reported cases of viral hepatitis B,of which Zhuji（49.40/100 000）,Yuecheng（44.17/100 000）and Xinchang（43.28/100 000）ranked top three in average annual incidence rate. The incidence rate of viral hepatitis B in men was 57.07/100 000,which was higher than 27.33/100 000 in women（P<0.05）.The age of onset was mainly 25-59 years old,with 16 941 cases（74.42%）reported. The top three occupations were farmers,workers and migrant workers,with 15 013（65.95%）,2 730（11.99%）and 1 121（4.92%）cases reported,respectively. Conclusions The incidence of viral hepatitis B in Shaoxing from 2008 to 2018 showed a downward trend. Farmers,workers and migrant workers aged 25-59 years were at high risk of hepatitis B infection.

Objective To screen and confirm cell fusion by DNA technology of parentage identification based on detecting of short tandem repeats.Methods With 20％ polyethylene glycol (PEG)-6000,human myeloma cell lines and health individual peripheral blood mononuclear cell were fused.Then selected by hypoxantin,aminopterin,thymidin (HAT) medium,and fusion cell were sub-cloned.Morphology of fusion cells was checked by regular microscope.Concentration of DNA was compared to parental cells.Allele genes,identified by short tandem repeats,of fusion cell line were sequenced and compared with each other.Results The fused cells from myeloma cell line and peripheral blood mononuclear cell (PBMC) were slightly larger than primary cells,and the proliferation cycle was not changed significantly.DNA concentration of the fused cell DNA was increased by two times.Sequences of short tandem repeats (STR) showed that the fused cell included all original genetic materials of parent cells.Conclusions DNA technology of parentage identification is a convenient and reliable method to screen and confirm fused cell.

OBJECTIVETo describe the prevalence and relationship between screen time and sub-health status among middle school students in weekdays and weekends.

METHODSWith multistage stratified random cluster sampling, 14 400 students from junior and senior middle schools in 288 classes of 30 schools in 4 cities( Shenyang, Chongqing, Xinxiang, Guangzhou) were investigated in October, 2011. A total of 13 817 valid questionnaires were retained for analysis. Survey content includes general demographic information, screen time, sub-health state. Logistic regression model was used to analyze the relationship between screen time and sub-health status.

RESULTSThe screen time among middle school students > 2 h/d on weekdays and weekends were 15.1% (2 085/13 817) and 58.5% (8 077/13 817) , respectively. Among them, the boys' screen time > 2 h/d on weekdays and weekends were 17.9% (1 187/6 644) and 61.3% (4 070/6 644), which were higher than girls (12.5% (898/7 173), 55.9% (4 007/7 173) )(χ² values were 76.95 and 41.35, respectively. P < 0.01). The prevalence of physical sub-health status, psychological sub-health status and sub-health status were 24.8% (3 431/13 817), 21.7% (2 997/13 817) and 22.1% (3 051/13 817), respectively. Among them, the girls' prevalence of physical sub-health status, psychological sub-health status and sub-health status were 26.0% (1 863/7 173), 22.9% (1642/7 173) and 23.1% (1 658/7 173) ), respectively, which were higher than boys' (23.6% (1 568/6 644), 20.4% (1 355/6 644) and 21.0% (1 393/6 644)) (χ² values were 10.39, 12.66 and 9.25, respectively. P < 0.05). The senior students' prevalence of physical sub-health status, psychological sub-health status and sub-health status were 31.6% (2 176/6 884) , 28.3% (1 946/6 884) and 28.9% (1 990/6 884), respectively, which were higher than junior students' (18.1% (1 255/6 933), 15.2% (1 051/6 933) and 15.3% (1 061/6 933)) (χ² values were 337.65, 349.46 and 371.54, respectively, P < 0.05). After adjusting on demographic characteristics, compared with screen time ≤ 2 h/d on weekday, screen time > 2 h/d on weekday was significantly associated with physical sub-health status, psychological sub-health status and sub-health status (OR (95% CI): 1.39 (1.25-1.55), 1.62 (1.45-1.81) and 1.59 (1.43-1.78)). And compared with screen time ≤ 2 h/d on weekend, screen time > 2 h/d on weekend was also significantly associated with physical sub-health status, psychological sub-health status and sub-health status (OR(95% CI):1.49 (1.37-1.61), 1.81 (1.66-1.98), and 1.71 (1.57-1.87)).

CONCLUSIONThe rate of the screen time > 2 h/d and the detection ratio of sub-health among the middle school students in Shenyang, Chongqing, Xinxiang, Guangzhou in 2011 were high. Screen time >2 h/d on weekdays or weekends was a risk factor for sub-health status.

Adolescent ; China ; epidemiology ; Cities ; Data Collection ; Female ; Health Status ; Humans ; Logistic Models ; Male ; Microcomputers ; statistics & numerical data ; Prevalence ; Risk Factors ; Schools ; Sex Factors ; Students ; Surveys and Questionnaires ; Television ; statistics & numerical data ; Urban Population ; statistics & numerical data