Funding for this research was provided by:
the Science Foundation of Guangxi Returned Oversea Scholars (0991004)
the National Natural Science Foundation of China (81460169)
Received: 1 January 2018
Accepted: 8 February 2018
First Online: 17 February 2018
Ethics approval and consent to participate
: All procedures of the investigation were carried out following the rules of the Declaration of Helsinki of 1975 (ExternalRef removed), revised in 2008. The study design was approved by the Ethics Committee of the First Affiliated Hospital, Guangxi Medical University (No. Lunshen 2009-Guike-018; Jan. 7, 2009). Informed consent was obtained from all participants.
: Not applicable.
: The authors declare that they have no competing interests.
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