Funding for this research was provided by:
Fundamental Research Business Expense of Universities in Heilongjiang Province (2018-KYYWFMY-0008)
Article History
Received: 24 July 2019
Accepted: 4 October 2019
First Online: 15 October 2019
Compliance with ethical standards
:
: All authors declare that they have no conflict of interest.
: Human and animal rights: no animal or human was involved in this study.
: Informed consent was obtained from all individual participants included in the study.