Funding for this research was provided by:
National Natural Science Foundation of China (61673141)
Alexander von Humboldt Foundation of Germany
Fok Ying Tung Education Foundation of China (151004)
Outstanding Youth Science Foundation of Heilongjiang Province of China (JC2018001)
University Nursing Program for Young Scholars with Creative Talents in Heilongjiang Province of China (UNPYSCT-2016029)
Article History
Received: 22 June 2018
Accepted: 4 December 2018
First Online: 25 January 2019
Compliance with ethical standards
:
: The authors claim that there are no potential conflicts of interest.
: In addition, this submission has been approved by all co-authors.