Funding for this research was provided by:
National Natural Science Foundation of China (81703240)
Text and Data Mining valid from 2020-01-06
Received: 6 November 2019
Accepted: 30 December 2019
First Online: 6 January 2020
Ethics approval and consent to participate
: The study was approved by the institutional review boards at Peking University (IRB00001052–18003), and all participants gave written informed consent at the enrollment.
: Not applicable.
: The authors declare that they have no competing interests.