Funding for this research was provided by:
National Natural Science Foundation of China (81621001, 81670167, 81530046)
Text and Data Mining valid from 2019-09-02
Received: 6 June 2019
Accepted: 16 August 2019
First Online: 2 September 2019
Ethics approval and consent to participate
: The study was approved by each institutional review board at the three participating institutions, and written informed consent was obtained from all subjects in accordance with the Declaration of Helsinki.
: Not applicable.
: The authors declare that they have no competing interests.