ABSTRACT
Objective:To determine the content of copper and zinc in tea by flame atomic absorption spectrophotometry and to investigate the influence on the content after leached for different time. Methods:The tea samples were leached for different time by boiling water and then the content of copper and zinc was determinated by flame atomic absorption spectrophotometry. Results:When the leaching time was less than 10 min, the content of copper and zinc increased significantly with the prolongation of the leaching time, while the increase was not obvious when the leaching time was more than 10 min. Copper and zinc showed good linearity in the range of 0.02-0.15 mg/L and 0.05-0.30 mg/L,separately. The recovery was in the range of 98.5%-101.1%for copper and 98.7%-101.2%for zinc with the RSD of 0.8%in copper and zinc (n=9) . Conclusion:The method is suitable to determine the content of copper and zinc in tea. Leaching time can influence the content of copper and zinc in tea significantly.
ABSTRACT
The talent medical colleges cultivate are to serve the society, and the society also proves them .How tomerge medical education and social development together to shorten the social adaptive period of medical students is animportant issue to be studied earnestly in higher education.[
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Objective To explore the effects of air pollution on children's nonspecific immune function,and find the sensitive indexes reflecting the earlier damages of human health induced by air pollution.Methods The data on air pollution were provided by Benxi and Shenyang environment protective bureaus. 300 children in grade 1 and grade 6,half for girls and half for boys were selected from area with slight air pollution and area with heavy air pollution in Shenyang and Benxi respectively by cluster sampling method.The contents of SIgA and the activities of bacteriolytic enzyme in saliva of children were measured by radioimmunoassay and agar spread assay respectively.Results The difference of the contents of saliva SIgA was observed in children in grade 1 between area with heavy air pollution(70.60 ?g/ml)and area with slight air pollution(97.77 ?g/ml),P
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Objective To study the effect of nonylphenol (NP) on the fertility of mice,and assess its reproductive and developmental toxicity.Methods 128 mature KM mice weighed 22-26 g were randomly divided into three experimental groups (24,60 and 120 mg nonylphenol/kg bw respectively) and the control group (earthnut oil ),16 in each.Fertility tests were performed according to the procedure commended by EPA.Results Sperm number,sperm vitality,fertility index and pregnancy rate decreased,while rate of deformed sperm increased in dose-dependent manner at dose of 60 and 120 mg/kg bw (P