Funding for this research was provided by:
National Natural Science Foundation of China (81670049, 81770057)
the National Key R&D Program in Shaanxi Province (2017SF-059)
Received: 15 August 2018
Accepted: 23 January 2019
First Online: 4 February 2019
Ethics approval and consent to participate
: The study protocol was approved by the Ethics Committee of the second affiliated hospital of Xi’an Jiaotong university. All participants read the purpose statement of the investigation, and each participant provided written informed consent.
: Not applicable.
: The authors declare that they have no competing interests.
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