An official website of the United States government
The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before
sharing sensitive information, make sure you’re on a federal
government site.
The site is secure.
The https:// ensures that you are connecting to the
official website and that any information you provide is encrypted
and transmitted securely.
Zhang Z, Cheng B, Tse-Dinh YC.Zhang Z, et al.Proc Natl Acad Sci U S A. 2011 Apr 26;108(17):6939-44. doi: 10.1073/pnas.1100300108. Epub 2011 Apr 11.Proc Natl Acad Sci U S A. 2011.PMID: 21482796Free PMC article.