Article History
First Online: 2 July 2018
Compliance with Ethical Standards
:
: The authors declare that they have no conflicts of interest.
: This study was approved by the Chonnam National University Institutional Review Board (1040198-16075-HR-063-01). All procedures performed involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Declaration of Helsinki and its later amendments or comparable ethical standards.
: Informed consent was obtained from all individual participants included in the study.