Funding for this research was provided by:
Guangdong Provincial Science & Tech Project (2015A020211016)
Guangzhou Industry-Academia-Research Collaborative Innovation Project (201604016009)
Text and Data Mining valid from 2019-03-23
Received: 7 July 2018
Accepted: 13 November 2018
First Online: 23 March 2019
Compliance with ethical standards
: All authors declare no conflict of interest.
: This article does not contain any studies with human participants.