Funding for this research was provided by:
Japan Society for the Promotion of Science (JP17K08924)
Received: 7 September 2018
Accepted: 9 April 2019
First Online: 17 May 2019
Ethics approval and consent to participate
: The study was approved by Jichi Medical University Clinical Research Ethics Committee (reference number: 15–154). Informed consent was obtained from all participants. The same statement is written in the end of the Introduction section.
: Informed consent was obtained from all participants for publication. All the authors have approved this publication.
: The authors declare that they have no competing interests.
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