Funding for this research was provided by:
National Natural Science Foundation of China (81301912)
Beijing Municipal Health System High-level Health Person Foundation Project (2014-3-005)
Beijing Municipal Science and Technology Commission (Z161100000516083)
Article History
Received: 4 February 2020
Accepted: 23 April 2020
First Online: 1 May 2020
Ethics approval and consent to participate
: Not applicable.
: All authors approved the final manuscript for publication.
: The authors declare that they have no competing interests.