Funding for this research was provided by:
Beijing Postdoctoral Research Foundation (2018-22-115)
Beijing Municipal Administration of Hospitals’ Youth Programme (QML20171202)
Beijing Health System Top Level Health Technical Personnel Training Plan (20153079)
Received: 28 November 2018
Accepted: 13 June 2019
First Online: 20 June 2019
Ethics approval and consent to participate
: This study was approved by the Ethics Committee of Beijing Children’s Hospital, Capital Medical University and written informed consent was obtained from all participants.
: Not applicable.
: The authors declare that they have no competing interests.