Funding for this research was provided by:
National Natural Science Foundation of Youth in China (81401758)
Text and Data Mining valid from 2018-07-03
Received: 28 February 2018
Accepted: 14 June 2018
First Online: 3 July 2018
Ethics approval and consent to participate
: Informed consent was obtained from all the individual participants included in the study. The study was conducted according to the Helsinki Declaration (Ethical Principles for Medical Research Involving Human Subjects) and was approved by the ethics committee of Peking Union Medical College Hospital.
: Not applicable.
: The authors declare that they have no competing interests.
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