1 Kyoto Institute of Technology, Ceramic Physics Laboratory, Sakyo-ku, Matsugasaki, Kyoto 606-8585, Japan. Electronic address: pezzotti@kit.ac.jp.
2 Tokyo Medical University, Department of Orthopaedic Surgery, Shinjuku-ku, Nishishinjuku, Tokyo 160-0023, Japan. Electronic address: kengo-y@tkg.att.ne.jp.