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.
Wada H, Satoh N.Wada H, et al.Proc Natl Acad Sci U S A. 1994 Mar 1;91(5):1801-4. doi: 10.1073/pnas.91.5.1801.Proc Natl Acad Sci U S A. 1994.PMID: 8127885Free PMC article.