Funding for this research was provided by:
National Natural Science Foundation of China (81801953, 81570400, 81470560, 81873534, 81600633, 81471036, 81702194, 81670411)
Key Technology Research and Development Program of Shandong (2018GSF118017, 2018GSF118002)
Natural Science Foundation of Shandong Province (ZR2017LH004)
the Natural Science Foundation of Shandong Province (ZR2014HQ037, ZR2017BH023)
the Science and Technology planning project of Yantai City (2016ZH083, 2018SFGY090)
Text and Data Mining valid from 2020-02-14
Received: 29 June 2019
Accepted: 29 November 2019
First Online: 14 February 2020
Ethics approval and consent to participate
: The study was conducted in accordance with the Declaration of Helsinki, and was approved by the Human Research Ethics Committee of Shandong University. All participants provided written informed consent.
: Not applicable.
: The authors declare no competing financial interests of this article.