Funding for this research was provided by:
Ministry of Health and Welfare (HI16C2177)
Received: 2 April 2018
Revised: 10 July 2018
Accepted: 16 July 2018
First Online: 13 August 2018
Ethics approval and consent to participate
: This study was approved by the Institutional Review Board (IRB) of the Catholic University of Korea (IRB number: KC13TISI0775). Written informed consent was obtained from all participants involved in this study.
: Not applicable.
: The authors declare that they have no competing interests.
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