Received: 30 May 2018
Accepted: 8 February 2019
First Online: 19 February 2019
Ethics approval and consent to participate
: The present study was approved by the ethics committee of Kawamura Hospital and was conducted according to the Declaration of Helsinki for human experiments. Informed consent was obtained from each subject before the experiments.
: Not applicable.
: The authors declare that they have no competing interests.
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