Funding for this research was provided by:
Zhejiang Provincial Natural Science Foundation of China (LY16H180001)
Article History
Received: 8 May 2018
Accepted: 23 July 2018
First Online: 30 July 2018
Compliance with ethical standards
:
: All 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 research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.
: The requirement for written informed consent was waived because this was a retrospective observational study.