Funding for this research was provided by:
the National Science Grant for Distinguished Young Scholars (81425001/H0104)
the National Key Technology Support Program from Ministry of Science and Technology (2015BAI12B11)
the Beijing Science and Technology Project (D151100002115004)
Text and Data Mining valid from 2018-04-24
Received: 17 September 2017
Accepted: 16 April 2018
First Online: 24 April 2018
Ethics approval and consent to participate
: This study was approved by the China-Japan Friendship Hospital Ethics Committee (2015–85). Given that the study was retrospective and all data were anonymous, the requirement for informed consent was waived.
: The authors declare that they have no competing interests.
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