Funding for this research was provided by:
National Natural Science Foundation of China (81570746)
Text and Data Mining valid from 2018-05-08
Received: 22 December 2017
Accepted: 7 February 2018
First Online: 8 May 2018
Ethics approval and consent to participate
: This study has been approved by the Ethics Committee of the First Affiliated Hospital of Zhengzhou University, and all participants of the study signed the informed consent.
: Not applicable.
: The authors declare that they have no competing interests.
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