1. Faculty of Nursing, Hirosaki Gakuin University, 20-7 Minori-cho, Hirosaki, Aomori 036-8231, Japan
2. Department of Pure and Applied Mathematics, Graduate School of Information Science and Technology, Osaka University, 1-1 Machikaneyama-cho, Toyonaka, Osaka 560-0043, Japan
3. The United Graduate School of Agricultural Sciences, Iwate University, Morioka 020-8550, Japan
4. Medical Research Institute, Tokyo Women's Medical University, 8-1 Kawada-cho, Shinjuku-ku, Tokyo 162-8666, Japan