Funding for this research was provided by:
Research Grants Council, University Grants Committee (General Research Fund (GRF/HKU 17611615))
Received: 13 July 2020
Accepted: 27 January 2021
First Online: 10 February 2021
Ethics approval and consent to participate
: Ethical approval was obtained from the institutional review board of the University of Hong Kong (IRB Reference Number: UW 15-115). All procedures conducted in this study were in accordance with the 1964 Helsinki declaration. All participants provided voluntary written informed consent before joining the study.
: Not applicable.
: The authors declare that they have no competing interests.