Article History
Received: 14 March 2018
Revised: 12 April 2018
Accepted: 24 April 2018
First Online: 30 April 2018
Compliance with ethical standards
: This study was conducted in compliance with the Helsinki Declaration to protect human subjects and was approved by the Institutional Review Board for Human Research, Konkuk University Medical Center (KUH Number 1010831). Written consent was obtained from all participants.
: None.