Funding for this research was provided by:
National Natural Science Foundation of China (81501001)
Beijing Outstanding Talent Training Projects (2014000021469G256)
Text and Data Mining valid from 2018-10-01
Received: 2 August 2017
Accepted: 17 September 2018
First Online: 1 October 2018
Ethics approval and consent to participate
: This study was performed according to the guidelines of Helsinki Declaration and was approved by both the Ethics Committees of the Kailuan General Hospital and Beijing Tiantan Hospital. Written informed consent was obtained from all participants and approved by the above ethics committees.
: Not applicable
: The authors declare that they have no competing interests.
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