Funding for this research was provided by:
National Natural Science Foundation of China (31372080)
Committee of Science and Technology of Chongqing, China (cstc2017jcyjAX0455)
Fundamental Research Funds for the Central Universities (106112013CDJZR290035)
Article History
Received: 7 December 2017
Accepted: 24 May 2018
First Online: 5 June 2018
Ethics approval and consent to participate
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: The authors declare that they have no competing interests.
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