Funding for this research was provided by:
Grant-in-aid for Scientific Research from the Japan Society for the Promotion of Science ((A) (16H02634))
Text and Data Mining valid from 2019-07-12
Received: 21 March 2019
Accepted: 2 July 2019
First Online: 12 July 2019
Compliance with ethical standards
: The authors declare that they have no competing interests.