Funding for this research was provided by:
National Natural Science Foundation of China (81470609, 81300730)
the National Natural Science Foundation of Shandong (ZR2017BH025)
Received: 26 October 2017
Accepted: 6 July 2018
First Online: 13 July 2018
Ethics approval and consent to participate
: The research adhered to the tenets of the Declaration of Helsinki and was approved by the Affiliated Hospital of Qingdao University ethics committee. All patients were adequately informed about the study and signed a consent form. It is available for review by the Editor of this journal if necessary.
: Details, images, or videos reported within the manuscript are consented for publication.
: The authors declare that they have no competing interests.
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