Funding for this research was provided by:
National Natural Science Foundation of China (No. 81301556)
Received: 18 June 2019
Accepted: 19 December 2019
First Online: 26 December 2019
Ethics approval and consent to participate
: The study was approved by The Medical Ethical Committee of Shandong Provincial Hospital Affiliated to Shandong University. The written informed consent was obtained from all patients included in this study.
: Not applicable.
: The authors declare that they have no competing interests.