Authors’ contributions
Study conception and design: Naoki Hiki, Keishi Yamashita, and Michitaka Honda. Acquisition of the data: Mikiko Sakuraya, Masahiro Niihara, Motohiro Chuman, Marie Washio, and Kei Hosoda. Analysis and interpretation of data: Mikiko Sakuraya, Michitaka Honda, Keishi Yamashita, and Naoki Hiki. Manuscript draft preparation: Mikiko Sakuraya, Keishi Yamashita, and Naoki Hiki. Critical revision: Keishi Yamashita, Kei Hosoda, Takeshi Naitoh, Yusuke Kumamoto, and Naoki Hiki.