Funding for this research was provided by:
Jiangfeng Du (31500620)
Wenshan Zhao (31700677)
Yanfeng Gao (U1604286, 1611003101000, 174200510022)
Text and Data Mining valid from 2018-06-07
Received: 28 February 2018
Accepted: 28 May 2018
First Online: 7 June 2018
Ethical approval and consent to participate
: Not applicable
: The authors declare that they have no competing interests.
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