Funding for this research was provided by:
Ibuka funding (NA)
Japan Society for the Promotion of Science (17J10680)
Received: 26 November 2018
Accepted: 31 January 2019
First Online: 18 February 2019
Ethics approval and consent to participate
: This study was carried out with the approval of the Waseda University Academic Research Ethical Review Committee. Written informed consent was obtained from all the study participants.
: Not applicable.
: The authors declare that they have no competing interests.
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