Text and Data Mining valid from 2019-01-23
Received: 8 October 2018
Accepted: 14 January 2019
First Online: 23 January 2019
Ethics approval and consent to participate
: The present study was approved by the Institutional Ethics Committee of Xiehe Hospital. Written informed consent was obtained from all participants.
: Not applicable.
: The authors declare that they have no competing interests.
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