Funding for this research was provided by:
National Natural Science Foundation of China (61301132, 61301131, 61601221)
Fundamental Research Funds for the Central Universities (3132016347)
Text and Data Mining valid from 2019-02-19
Received: 14 September 2018
Accepted: 6 February 2019
First Online: 19 February 2019
: The authors declare that they have no competing interests.
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