Funding for this research was provided by:
Singapore Academic Research Fund (R-397-000-173-133)
Article History
Received: 13 December 2017
Accepted: 20 August 2019
First Online: 12 September 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 institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards. For this type of retrospective study, formal consent is not required. This article does not contain any studies with animals performed by any of the authors.
: Informed consent was obtained from all individual participants included in the study. Any participation in the study is voluntary and identities of participants are kept anonymous.