Funding for this research was provided by:
Funded by the Yunnan Provincial Science and Technology Department (2007C0021R)
Text and Data Mining valid from 2018-06-15
Received: 23 March 2018
Accepted: 1 May 2018
First Online: 15 June 2018
Ethics approval and consent to participate
: The study was approved by the University ethics committee. Written informed consent was obtained from each study participant.
: The authors declare that they have no competing interests.
: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.