Text and Data Mining valid from 2018-10-03
Received: 5 April 2018
Accepted: 13 September 2018
First Online: 3 October 2018
Ethics approval and consent to participate
: This research conformed to the provisions of the Declaration of Helsinki. This retrospective study was approved by the ethics committee of Kobe University (approval No.160122) and each institutions. Consent to participate: this is a retrospective study and consent to participate was waived by the Ethics Committee of Kobe University and each institution.
: Not applicable.
: The authors declare that they have no competing interests.
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