Xing, Haijian
Tian, Gang
Article History
Received: 11 December 2019
Accepted: 30 March 2020
First Online: 10 April 2020
Ethics approval and consent to participate
: The study protocol conformed to the ethical guidelines of the 1975 Declaration of Helsinki (6th revision, 2008) as reflected in a priori approval by Ethics Committee of Xi’an Jiaotong University. Written informed consent was obtained from the legal guardians of each studied subject.
: Not applicable.
: The authors declare that they have no competing interests.