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.
Rypma B, D'Esposito M.Rypma B, et al.Proc Natl Acad Sci U S A. 1999 May 25;96(11):6558-63. doi: 10.1073/pnas.96.11.6558.Proc Natl Acad Sci U S A. 1999.PMID: 10339627Free PMC article.