Liu, Qifang
Liu, Shuang
Wang, Xiaoying
Zhang, Jin
Liu, Kuiran
Article History
Received: 5 June 2019
Accepted: 21 August 2019
First Online: 20 November 2019
Ethics approval and consent to participate
: Shengjing Hospital affiliated to China medical university Ethics Committee approved this study. All procedures performed in studies involving human participants were in accordance with the 1964 Helsinki declaration and its later amendments or comparable ethical standards. Written informed consent was obtained from all individual participants included in the study.
: Not applicable.
: The authors declare that they have no competing interests.