Xie, Huihui
Zhang, Xiaodong
Ma, Shuai
Liu, Yi
Wang, Xiaoying
Article History
First Online: 8 March 2019
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 with the 1964 Helsinki declaration and its later amendments. For this type of study, formal consent is not required.