Funding for this research was provided by:
National Natural Science Foundation of China (81500275)
Natural Science Foundation of Guangdong Province (2016A030313080)
the Fundamental Research Funds for the Central Universities (21616323)
Text and Data Mining valid from 2019-01-17
Received: 15 April 2018
Accepted: 17 December 2018
First Online: 17 January 2019
Ethics approval and consent to participate
: This study was approved by the Ethics Committee at Guangzhou Women and Children’s Medical Center (trial no. 077 2013). Written informed consent for participation in this study was obtained by each child participants’ legal guardian on their behalf. A copy of the written consent is available for review by the Editor of this journal.
: Not applicable.
: The authors declare that they have no competing interests.
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