Funding for this research was provided by:
Natural Youth Science Foundation of China (61401310)
Tianjin Science Foundation (18JCYBJC86400)
Text and Data Mining valid from 2019-04-03
Received: 13 January 2019
Accepted: 19 March 2019
First Online: 3 April 2019
: The authors declare that they have no competing interests.
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