Funding for this research was provided by:
Foundation for Innovative Research Groups of the National Natural Science Foundation of China (81821092)
National Basic Research Program of China (973 Program) (2019YFA0706204)
Beijing Municipal Science and Technology Commission (Z181100001718051)
Received: 15 April 2020
Accepted: 12 August 2020
First Online: 24 August 2020
Ethics approval and consent to participate
: The study was approved by the Institutional Review Board of Peking University Sixth Hospital. This was an anonymous survey, and confidentiality of data was ensured. Written informed consent was received online before the respondents began the questionnaire.
: Not applicable.
: The authors declare that they have no competing interests.