Funding for this research was provided by:
National Natural Science Foundation of China (31300799, 51537004)
Independent Innovative Research Fundf HUST (2014QN094)
Text and Data Mining valid from 2018-05-21
Received: 27 December 2017
Revised: 3 April 2018
Accepted: 20 April 2018
First Online: 21 May 2018
: The authors declare that they have no competing interests.
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