Iizumi, Sakura http://orcid.org/0000-0001-6760-152X
Takashima, Atsuo http://orcid.org/0000-0002-8456-1248
Sakamaki, Kentaro
Morita, Satoshi
Boku, Narikazu
Article History
Received: 27 December 2017
Accepted: 22 March 2018
First Online: 29 March 2018
Compliance with ethical standards
:
: The authors have declared no conflicts of interest.
: This study itself does not involve any interventions on human participants or animals performed by any of the authors. Ethical approval was not required for this study because only publicly available data were used.
: Informed consent was not required for this study.