Guo, Yanxiu
Zeng, Haoxia
Chang, Xiaohong
Wang, Chaohua
Cui, Heng
Article History
Received: 17 April 2017
Accepted: 14 December 2017
First Online: 16 January 2018
Ethics approval
: The study was approved by the Institutional Ethics Review Boards of Peking University People’s hospital.
: Not applicable.
: The authors declare that they have no competing interests.
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