Funding for this research was provided by:
Postdoctoral Scientific Research Developmental Fund of Heilongjiang Postdoctoral Program, China (No. LBH-Q16143)
Article History
Received: 27 March 2018
Accepted: 1 June 2018
First Online: 11 June 2018
Compliance with ethical standards
:
: The authors declared that they have no conflict of interest.
: All procedures performed in studies involving human participants were in accordance with the Ethical Review Committee of Second Affiliated Hospital of Harbin Medical University and with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards. For this retrospective study formal consent is not required.
: Informed consent was obtained from all individual participants included in the study.