Funding for this research was provided by:
National Natural Science Foundation of China (81502518, 81372843, 81702624)
Natural Science Foundation of Tianjin City (17JCQNJC10400)
Received: 28 October 2018
Accepted: 13 January 2019
First Online: 18 January 2019
Ethics approval and consent to participate
: This study was approved by the Institutional Review Board of TMUCIH and written consent was obtained from all participants.
: Not applicable.
: The authors declare that they have no competing interests.
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