Text and Data Mining valid from 2019-06-14
Received: 31 July 2018
Accepted: 21 April 2019
First Online: 14 June 2019
Ethics approval and consent to participate
: The study was approved by the Institutional Review Board of Osaka University Hospital. Written informed consent for participation, in accordance with the principles of the Declaration of Helsinki, was obtained from all participants and their guardians.
: Not applicable.
: The authors declare that they have no competing interests.
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