Funding for this research was provided by:
National Natural Science Foundation of China (81770679, 81470973)
Shandong Science and Technology Development Program (2010G0020222)
Text and Data Mining valid from 2018-10-05
Received: 23 June 2018
Accepted: 24 September 2018
First Online: 5 October 2018
Compliance with ethical standards
: All authors declared that they have no conflict of interest.
: This article does not contain any original studies with human participants by any of the authors.