Text and Data Mining valid from 2020-01-16
Received: 21 October 2019
Accepted: 9 January 2020
First Online: 16 January 2020
Ethics approval and consent to participate
: Institutional ethical committee approval was obtained (Nagoya City University Graduate School of Medical Science, Nagoya, Japan, approval number 60-19-0014).
: Not applicable.
: The authors declare that they have no competing interests.