Funding for this research was provided by:
National Natural Science Foundation of China (81470359)
Received: 9 April 2019
Accepted: 4 July 2019
First Online: 17 July 2019
Ethics approval and consent to participate
: The study was approved by the ethics committee of Peking University First Hospital (No. 2018). No consent to participate was needed from the participants.
: The authors declare that they have no competing interests.