Funding for this research was provided by:
National Natural Science Foundation of China (51705233)
Science and Technology Planning Project of Shenzhen City (GRCK2017082316213662)
Text and Data Mining valid from 2019-09-10
Received: 1 July 2019
Accepted: 12 August 2019
First Online: 10 September 2019
: The authors declare that they have no competing interests.