Funding for this research was provided by:
National Natural Science Foundation of China (81571311, 81271499, 81571331, 81071099)
Received: 21 October 2018
Accepted: 28 January 2019
First Online: 11 February 2019
Ethics approval and consent to participate
: The study was conducted in accordance with the latest version of the Declaration of Helsinki and approved by the Institutional Review Board of the China Medical University. Each participant provided written informed consent prior to commencement of the study.
: Not applicable.
: The authors declare that they have no competing interest.
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