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.
McCaffrey RL, Fawcett P, O'Riordan M, Lee KD, Havell EA, Brown PO, Portnoy DA.McCaffrey RL, et al.Proc Natl Acad Sci U S A. 2004 Aug 3;101(31):11386-91. doi: 10.1073/pnas.0403215101. Epub 2004 Jul 21.Proc Natl Acad Sci U S A. 2004.PMID: 15269347Free PMC article.