11 January 2013
Vol 339, Issue 6116

About The Cover

Cover image expansion

COVER A yin-yang symbol superimposed on a scanning electron micrograph of a mouse tissue alveolar macrophage (diameter: ~18 micrometers). Macrophages are immune cells that mediate inflammation, but they often play protective roles as well. Several age-related chronic diseases—such as metabolic syndrome, cardiovascular disease, and neurodegenerative disease—have an inflammatory component. See the special section beginning on page 155. Scanning electron microscope image: © Dennis Kunkel Microscopy, Inc.