Funding for this research was provided by:
Natural Science Foundation of Guangdong Province (2017A030307027)
Funds of Science & Technology Research of Guangdong Province, China (2017A040403070, 2015B010128015)
Text and Data Mining valid from 2018-05-09
Received: 3 February 2018
Accepted: 25 April 2018
First Online: 9 May 2018
: The authors declare that they have no competing interests.
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