Wang, Yanxia
Ma, Liji
Li, Ying
Li, Yuyun
Zheng, Yanfei
Zhang, Xiaoyue
Article History
Received: 20 December 2019
Accepted: 28 February 2020
First Online: 6 March 2020
Ethics approval and consent to participate
: This study was approved by the Ethics Committee of Zibo Central Hospital. Written informed consent was obtained from the guardians of the patients.
: Not applicable.
: The authors declare that they have no competing interests.