Funding for this research was provided by:
JSPS KAKENHI (17K10954)
Received: 17 May 2018
Accepted: 23 July 2018
First Online: 31 July 2018
Ethics approval and consent to participate
: The research protocol was in compliance with the Helsinki Declaration, approved by the Research Ethics Committees of Graduate School of Medicine, Chiba University (reference number 670) and registered with the University Hospital Medical Information Network. Written informed consent was obtained from all study participants.
: Informed consent for publication was obtained from the families of all the participants.
: The authors declare that they have no competing interests.
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