1. Graduate School of Integrated Science and Technology, Shizuoka University, Hamamatsu, Shizuoka 432-8561, Japan
2. Research Institute of Electronics, Shizuoka University, Hamamatsu, Shizuoka 432-8011, Japan
3. Office of Institutional Research, Hokkaido University, Sapporo, Hokkaido 060-0808, Japan
4. Division of Microscopic Anatomy, Graduate School of Medical and Dental Sciences, Niigata University, Niigata 951-8510, Japan