Correspondence should be addressed to You-Ming TAN. Tel: 86-21-63846590-776197. Fax: 86-21-63850472. E-mail: ym_tan@tom. tom or werther_tan@yahoo, com. cn You-Ming TAN, male, born in 1969, associate professor, received Ph. D. degree at Tongji Medical College, Huazhong University of Science and Technology in 2002, majoring in environmental hygiene.