Funding for this research was provided by:
Shengjing Hospital Science and Technology Program (MC05)
Received: 7 March 2019
Accepted: 30 August 2019
First Online: 5 September 2019
Ethics approval and consent to participate
: Ethical approval (No. 2018PS509K) was granted by the Institutional Research and Ethics Committee of the Shengjing Hospital Affiliated China Medical University. Informed consent was obtained from all eligible residents and was written and obtained.
: Not applicable.
: Tong Tong certifies that there are no conflicts of interest, including those related to specific financial interests, relationships or affiliations relevant to the subject matter or materials discussed in the manuscript (e.g., employment/affiliation, grants or funding, consultancies, honoraria, stock ownership or options, expert testimony, royalties, or patents filed, received, or pending).