1. Department of Neurosurgery, Shinshu University School of Medicine, Matsumoto, Japan
2. Institute of Engineering, Academic Assembly, Shinshu University, Nagano, Japan
3. Institute of Carbon Science and Technology, Interdisciplinary Cluster for Cutting Edge Research, Shinshu University, Nagano, Japan
4. Department of Mechanical Systems Engineering, Shinshu University, Nagano, Japan