Article History
First Online: 11 October 2019
Compliance with Ethical Standards
:
: The authors declare that they have no conflict of interest.
: All procedures performed in studies involving human participants were in accordance with the ethical standards of the Human Research Ethics Committee, the University of Hong Kong (EA1707026) and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.
: Written informed consent was obtained from all individual participants included in this study.