Liu, Guobin
Li, Yansen
Zhu, Yanbin
Chen, Wei
Xing, Xin
Shao, Jiashen
Liu, Song
Lv, Hongzhi
Ji, Chenni
Zhang, Xiaolin
Zhang, Yingze
Article History
Received: 16 October 2018
Accepted: 14 April 2019
First Online: 29 May 2019
Compliance with ethical standards
: The CNFS was approved by the Institutional Review Board of the 3rd Hospital of Hebei Medical University. Written informed consent was obtained from each participant before data collection.
: The authors declare that they have no competing interests.