Funding for this research was provided by:
Shandong Provincial Science Foundation (ZR2016CM25)
Text and Data Mining valid from 2019-08-13
Accepted: 9 August 2019
First Online: 13 August 2019
Compliance with Ethical Standards
: The authors declare that they have no conflict of interest.
: No human or animal subjects were involved in the experiments, so an ethical approval was not required.
: Informed consent was not required in this study.