Funding for this research was provided by:
China National Health and Planned Parenthood Committee Health Quality Improvement Award (201402017)
China Nature Science Foundation (31070930)
3M unrestricted research grant (MDI0091)
Article History
Received: 12 December 2017
Accepted: 21 August 2018
First Online: 8 September 2018
Ethics approval and consent to participate
: This study protocol was approved by Institute Review Boards (IRB) of Peking Union Medical College Hospital (PUMCH) in Beijing, China. Written informed consent was obtained from patients or surrogates prior to screening.
: Not applicable.
: The authors declare that they have no competing interests.
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