Funding for this research was provided by:
Specific Fund of Clinical Medical Research of Chinese Medical Association (10030180240)
National Natural Science Foundation of China (81200238)
Received: 13 December 2015
Accepted: 2 March 2016
First Online: 4 April 2016
Compliance with ethical standards
: All authors declare that they have no conflict of interest regarding the submission and publication of the work reported here.
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