Funding for this research was provided by:
National Natural Science Foundation of China (61805160)
Natural Science Foundation of Guangdong Province (Grant No. 2017A030310325)
Department of Education of Guangdong Province (2017KTSCX160)
the key Project department of Education of Guangdong Province (Grant No. 2016KQNCX146)
Natural Science Foundation of SZU (2018047, Grant No. 2017009)
Text and Data Mining valid from 2019-02-05
Received: 30 October 2018
Accepted: 20 January 2019
First Online: 5 February 2019
: The authors declare that they have no competing interests.
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