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Article History

Received: 4 September 2019

Accepted: 7 November 2019

First Online: 16 November 2019

Compliance with ethical standards

:

: The authors declare that they have no conflicts of interest.

: All procedures performed in studies involving human participants were in accordance with the ethical standards of the Institutional Review Board of Severance Hospital, Yonsei University, Seoul, Korea (4-2015-1068) and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.

: Informed consent was obtained from all individual participants included in the study.