Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
Location of nanogold particles at different times after the introduction of oxygen. The number of particles counted is 138, 216, 164 and 178 at 0, 2, 5 and 30 min, respectively; error bars show the standard error from repeated blind-independent counting of the same images.
