1. Tohoku Univ.,Grad. Sch. Biomed. Eng.,Sendai,Japan
2. Tohoku Univ.,Grad. Sch. Eng.,Sendai,Japan
3. Fukushima Med. Univ.,Dept. Epidemiol.,Fukushima,Japan
4. Tohoku Univ.,Grad. Sch. Med.,Sendai,Japan
5. Intl. Univ. Health & Welfare,Grad. Sch. Med.,Narita,Japan