1. School of Medicine, Tohoku University, 2-1 Seiryo-machi, Aobaku, Sendai, Miyagi 980-0875, Japan
2. Institute of Development, Aging and Cancer, Tohoku University, Sendai, Japan
3. International Research Institute of Disaster Science, Tohoku University, Sendai, Japan
4. Center for Information and Neural Networks, National Institute of Information and Communications Technology, Osaka, Japan
5. Faculty of Engineering, Tohoku Institute of Technology, Sendai, Japan