Funding for this research was provided by:
Young Scientists Fund (81601253)
National Natural Science Foundation of China (31471404)
Received: 15 October 2018
Accepted: 29 March 2019
First Online: 12 April 2019
Ethics approval and consent to participate
: Study protocols were approved by the Zhengzhou University Research Ethics Board and all participants provided informed consent prior to enrollment.
: Not applicable.
: The authors declare that they have no competing interests.
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