Funding for this research was provided by:
Natural Science Foundation of Heilongjiang Province (D201224)
Heilongjiang Provincial Health and Family Planning Commission on Scientific Research Project (2017-405)
Text and Data Mining valid from 2018-08-22
Received: 1 February 2018
Accepted: 1 August 2018
First Online: 22 August 2018
Ethics approval and consent to participate
: The study protocol was approved by the Ethics Committee of Jiamusi University Clinical Medical College for research. The committee’s reference number is 0326. Individual informed consent was waived by the ethics committee listed above because this study used currently existing sample collected during the course of routine medical care and did not pose any additional risks to the patients.
: Not applicable.
: The authors have declared that no competing interests.
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