Funding for this research was provided by:
National Natural Science Foundation of China (61671390)
China Postdoctoral Science Foundation (2015M570776)
Fundamental Research Fund for Central University (SWU113044)
Text and Data Mining valid from 2018-06-15
Received: 1 November 2017
Accepted: 25 May 2018
First Online: 15 June 2018
: The authors declare that they have no competing interests.
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