Funding for this research was provided by:
National Natural Science Foundation of China (81602440)
Weifang University of Science and Technology (2017RKX088)
Text and Data Mining valid from 2019-07-09
Received: 22 February 2019
Accepted: 28 June 2019
First Online: 9 July 2019
Ethics approval and consent to participate
: All procedures performed in this study involving were in accordance with the ethical standards of the institutional research committee of Weifang medical university and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.
: Not applicable.
: The authors declare that they have no competing interests.