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Article History

Received: 4 May 2018

Accepted: 4 December 2018

First Online: 19 December 2018

Ethical approval and consent to participate

: All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards. This study was approved by the Ethics Committee of West China Hospital, and written informed consent was obtained from all the participants.

: Not applicable.

: The authors declare that they have no competing interests..

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