Hui, Liu
Article History
Received: 11 June 2018
Accepted: 25 September 2018
First Online: 3 October 2018
Ethics approval and consent to participate
: The Institutional Ethics Committee of Dalian Medical University approved the study and waived the need for written informed consent from the participants due to the observational nature of the study.
: Not applicable
: The author declares that he/she has no competing interests.
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