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.
Kao JP, Tsien RY.Kao JP, et al. Among authors: tsien ry.Biophys J. 1988 Apr;53(4):635-9. doi: 10.1016/S0006-3495(88)83142-4.Biophys J. 1988.PMID: 3382715Free PMC article.