Funding for this research was provided by:
National Natural Science Foundation of China (81670426)
Received: 2 September 2017
Accepted: 15 May 2018
First Online: 18 July 2018
Ethics approval and consent to participate
: All the subjects provided written informed consent. The study was approved by the Medical Ethics Committee of the Second Xiangya Hospital of Central South University and was conducted in accordance with approved guidelines and regulations.
: The authors declare that they have no competing interests.
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