Funding for this research was provided by:
Japan Society for the Promotion of Science (18K07949, 15K08973, 15H04299, 18K07977, 16K19352)
Text and Data Mining valid from 2019-05-07
Received: 5 February 2019
Accepted: 23 April 2019
First Online: 7 May 2019
Ethics approval and consent to participate
: This study was approved by the Institutional Review Board of Sapporo Medical University.
: Not applicable.
: The authors declare that they have no competing interests.
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