Funding for this research was provided by:
National Natural Science Foundation of China (81590951, 81403482, 81373737)
Ministry of Science and Technology of the People's Republic of China (2012CB518501)
Text and Data Mining valid from 2018-12-01
Received: 9 May 2018
Accepted: 15 November 2018
First Online: 13 December 2018
: The authors declare no competing interests.