1. Department of Organ Anatomy & Nanomedicine, Graduate School of Medicine, Yamaguchi University, 1-1-1 minami-Kogushi, Ube, Yamaguchi 755-8505, Japan
2. Core Clusters for Research Initiatives of Yamaguchi University, 1-1-1 minami-Kogushi, Ube, Yamaguchi 755-8505, Japan