Text and Data Mining valid from 2020-01-30
Received: 14 October 2019
Accepted: 30 December 2019
First Online: 30 January 2020
Ethics approval and consent to participate
: This study procedure was approved by the institutional review boards of our institution, and conformed to the standards set by the Declaration of Helsinki. The written informed consent from all subjects was obtained before participation in this study.
: Not applicable.
: The authors declare that they have no competing interests.