Text and Data Mining valid from 2019-12-01
Received: 18 September 2019
Accepted: 19 December 2019
First Online: 27 December 2019
Ethics approval and consent to participate
: All study participants provided informed consent, and we obtained general consent to the research in written form from the participant.This study was conducted in accordance with the ethical standards defined in the Declaration of Helsinki and was approved by the ethics committee of the University of Tsukuba.(T-CReDO, H30–188).
: We obtained consent for publication in written form from the participant.
: We have no competing interests.