Funding for this research was provided by:
Grant-in-Aid for Scientific Research (C
Text and Data Mining valid from 2018-03-15
Received: 24 December 2017
Accepted: 6 February 2018
First Online: 15 March 2018
Compliance with ethical standards
: Ayori Mitsutake declares that he has no conflicts of interest. Hiroshi Takano declares that he has no conflicts of interest.
: This article does not contain any studies with human participants or animals performed by any og the authors.