Text and Data Mining valid from 2018-03-27
Received: 15 January 2018
Accepted: 16 March 2018
First Online: 27 March 2018
Ethics approval and consent to participate
: The Ethics Committee of Xinhua Hospital approved the study. The informed consent was waived because this is a retrospective study.
: The written consent is available for review by the chief editor.
: The authors declare that they have no competing interests.
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