Funding for this research was provided by:
JSPS KAKENHI (16K13031)
Text and Data Mining valid from 2019-06-03
Received: 31 March 2019
Accepted: 22 May 2019
First Online: 3 June 2019
Ethics approval and consent to participate
: This study was approved by the Ethics Committee of the Faculty of Arts and Science, Kyushu University, Japan (approval number: 201602R).
: No applicable.
: The authors declare that they have no competing interests.