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Article History

Received: 10 July 2018

Accepted: 17 December 2018

First Online: 27 December 2018

Ethics approval and consent to participate

: All participants have given informed and written consent. This study was approved by the ethics committee of Liaocheng People’s Hospital, and followed the ethical guidelines laid down in the 1975 Declaration of Helsinki.

: All participants have given consent for publication.

: The authors declare that they have no competing interests.

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