Funding for this research was provided by:
the National Natural Science Foundation of China (81773339)
the Science and Technology Department of Hunan Province, China (2017WK2041)
Received: 11 July 2017
Accepted: 26 March 2018
First Online: 10 April 2018
Ethics approval and consent to participate
: All participants understood the nature of the research project and provided written informed consent to participate in this study. Permission for this study was obtained from the Ethical Committee of the Second Xiangya Hospital of Central South University. (approval No. 235).
: Not applicable.
: The authors declare that they have no competing interest.
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