Text and Data Mining valid from 2020-01-03
Received: 6 September 2019
Accepted: 17 December 2019
First Online: 3 January 2020
Ethics approval and consent to participate
: Studies were approved by the Ethics Committee of the First Affiliated Hospital of Zhengzhou University, and all of the samples were obtained with written informed consent and analyzed anonymously. The study was conducted in accordance with the Declaration of Helsinki.
: Not applicable.
: The authors declare that they have no competing interests.