Funding for this research was provided by:
Ministry of Education, Culture, Sports, Science, and Technology (15H009382, 15H00918, 16K13945, 16K00175, JP26102006, 18H03908)
Text and Data Mining valid from 2018-09-27
Received: 4 April 2018
Accepted: 30 August 2018
First Online: 27 September 2018
: The authors declare no competing interests.