Funding for this research was provided by:
National Natural Science Foundation of China (81272362)
Text and Data Mining valid from 2019-04-04
Received: 28 November 2018
Accepted: 27 March 2019
First Online: 4 April 2019
Compliance with ethical standards
: The authors declare that they have no conflict of interest.
: All procedures in this study that involved human participants were performed in accordance with the 1964 Helsinki declaration and its later amendments. The protocol was approved by the Ethics Committee of The Affiliated Hospital of Qingdao University. Informed consent was obtained from all individual participants included in the study. Furthermore, the care and use of laboratory animals was in accordance with the principles and standards set forth in the Principles for Use of Animals (National Guide for Grants and Contracts).
: Informed consent was obtained from all individual participants included in the study.