Text and Data Mining valid from 2019-11-01
Received: 21 March 2019
Accepted: 14 October 2019
First Online: 1 November 2019
Ethics approval and consent to participate
: Ethics approval was received from Peking University Institutional Review Board with reference number: IRB00001052–17063. Written informed consent was obtained for all research participants.
: Not applicable.
: The authors declare that they have no competing interests.