Affiliation: | (1) Department of Public Health, Gunma University, School of Medicine, Showa-3, Maebashi 371, Japan , JP;(2) Faculty of Mathematics and Natural Sciences, University of Lampung, Bandar Lampung, Indonesia , ID;(3) Department of Environmental Health Sciences, Tohoku University, School of Medicine, 2-1 Seiryo-Machi Aoba-ku, Sendai 980-77, Japan , JP |