Funding for this research was provided by:
Natural Science Foundation of Shaanxi Province (2018JM7026)
Xi'an Science and Technology Project (201805102YX10SF36(3))
Fundamental Research Funds for the Central Universities in Xi’an Jiaotong University (xjj2018272)
Text and Data Mining valid from 2019-12-02
Received: 22 May 2019
Accepted: 24 October 2019
First Online: 2 December 2019
Compliance with ethical standards
: The authors declare that they have no conflict of interest.
: 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.
: Informed consent was obtained from all individual participants included in the study.