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.
a Halogen assay image with negative results (no haloes). b Halogen assay image with positive results. c Image with haloed particles serving as an example to demonstrate the 3 image adjustments used to confirm and identify the reactive particles. d Inverted image. e Sections of the image enlarged 400% with Adobe Photoshop with the Blow-up plug-in. f Highlighted edges of the particles that were hidden by the halo.
