Funding for this research was provided by:
Japan Society for the Promotion of Science (partially 15KK0229, KAKENHI grant numbers 25709063)
Text and Data Mining valid from 2019-01-07
Received: 2 October 2018
Accepted: 17 December 2018
First Online: 7 January 2019
Compliance with ethical standards
: All authors declare that they have no conflict on interest.