Funding for this research was provided by:
National Natural Science Foundation of China (31770837)
Qingdao People’s Livelihood Science and technology plan (18-6-1-68-nsh)
Text and Data Mining valid from 2019-08-31
Received: 3 July 2019
Accepted: 15 August 2019
First Online: 31 August 2019
Ethics approval and consent to participate
: The study protocol was approved by the Ethics Committee of Qingdao Municipal Hospital before participation (Approval NO.2017–20). All the subjects have signed written informed consent.
: Not applicable.
: The authors declare that they have no competing interests.