Objective To explore the relationships between the screen time with parent-child relations as well as social ability and behavioral problem in preschool children.Methods A total of 866 children aged 3-6 years old in Dazhou City conducted the sampling survey by adopting the children screen time questionnaire,parent-child relationship self-rating scale and young children's social ability and behavior assessment scale(SCBE-30).The single factor analysis and multinomial Logistic regression method were used to conduct the statistical analysis.Results The surveyed preschool children watching TV every day accounted for 99.31 ％,those playing mobile phones every day accounted for 81.87％ and those using computer accounted for 68.36％s.The average daily screen time at ordinary time was 1.75 h/d,those ≥2 h/d accounted for 16.05％;the average screen time at the weekend was 2.32 h/d,those ≥2 h/d accounted for 46.57％.The univariate analysis showed that the screen time in boy,left behind children,only child,mothers engaging in agriculture of peasant-worker or housewife was longer(P＜0.05);the screen time affected the social ability and behavior problems of children(P＜0.05).The longer the time children spent with their parents every day,the higher the parent-child relationship score(P＜0.05);the screen content affected the parent-child relationship and anxiety withdrawal behavior (P＜0.05).The polynormial regression analysis between the children's screen time with social ability,behavior problems,parent-child relation and contacting screen mode showed that the screen time had the negative effect relation with the social ability and parent-child relation(parents and children questionnaire) score(β=-1.115,-1.728,-1.909,P＜0.05),and had the positive effect relation with the scores of anger attack behavior and anxiety retreat behavior,and individual contacting screen (β=0.982,1.474,0.877,P＜0.05).Conclusion The screen time in preschool children is related with parent-child relation,social ability and behavioral problems.The parental accompany is beneficial to the development of parentchild relations in preschool children.

Objective To discuss a optimal culture method of primary hippocampal neurons and a more suitable method of mor-phological observation ,and provide basis to the study of synapse in Alzheimer′s Disease .Methods Postnatal 0 -1 days (P0 -1 ) C57BL/6J mice were decollated and bilateral hippocampus were separated .Low level concentration of trypsin and mechanical disso-ciation were adopted .And culture medium without serum was used to culture neurons .After 17 days culturing ,transfected neurons with Green Fluorescent Protein(GFP) by calcium phosphate precipitation ,and then observed neurons and spines by fluorescence mi-croscope .Results The neurons looked good and healthy by using this method .And the axons ,dendrites and spines which were typ-ical structure of neurons were observed clearly after transfected with GFP .Conclusion The cultured hippocampal neurons look good by this method .And the morphological characteristics of neurons and spines are observed much more clearly after transfected GFP by calcium phosphate precipitation .

OBJECTIVE:To compare and analyze blood concentration changes of fluorouracil administered to guinea pigs by different paths.METHODS:The peripheral vein and portal vein blood samples of guinea pigs were taken at different time after administered with fluorouracil in3different ways:group A(by arterial infusion),group B(by intravenous infusion)and group C(by celiac infusion).The blood concentration changes were determined and analyzed by HPLC.RESULTS:The portal vein and peripheral vein blood concentrations in group A and B reached peak value5min after administration with flu?orouracil while group C reached peak at10min;the portal vein blood concentrations in group A reached the highest in the first20min while group C showed the highest value in the last30min.CONCLUSION:Arterial infusion combining celiac infusion path was recommended for local chemotherapy;arterial infusion combining intravenous infusion or intravenous infusion com?bining celiac infusion was recommended for the local therapy while giving consideration to systemic chemotherapy.