Text and Data Mining valid from 2018-08-28
Received: 19 June 2018
Accepted: 20 August 2018
First Online: 28 August 2018
Ethics approval and consent to participate
: This study was approved by the Institutional Review Board of Chungnam National University Hospital, and the requirement for informed consent was waived. This study was conducted in accordance with the latest version of the Declaration of Helsinki.
: Not applicable.
: The authors declare that they have no competing interests.
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