1. Division of Medical Devices; National Institute of Health Sciences; 1-18-1 Kamiyoga Setagaya Tokyo 158-8501 Japan
2. Division of Oral Science & Pharmacology, Department of Dental Hygiene, School of Nursing; Kanagawa Dental University; 82 Inaoka-cho Yokosuka Kanagawa 238-8580 Japan
3. R&D Center, NH Foods Ltd.; 3-3 Midorigahara Tsukuba Ibaraki 300-2646 Japan