Funding for this research was provided by:
National Natural Science Foundation of China (81470647)
Article History
Received: 7 September 2017
Revised: 15 March 2018
Accepted: 26 March 2018
First Online: 6 April 2018
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 (name the institution/committee) and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.For this type of study, formal consent is not required.
: Informed consent was obtained from all individual participants included in the study.