Funding for this research was provided by:
Fundación para el Fomento en Asturias de la Investigación Científica Aplicada y la Tecnología (JSPS KAKENHI Grant Number 17K15889)
Received: 21 March 2019
Accepted: 26 July 2019
First Online: 5 August 2019
Ethics approval and consent to participate
: This study protocol was approved by the institutional review board of the University of Tokyo (reference no. 11779). Written informed consent was obtained from all participants or their families.
: Not applicable.
: The authors declare that they have no competing interests.