Cells are dynamic, fast-changing, complex, tiny, and often hard-to-see in environments that don’t always behave in predictable ways when exposed to external stimuli. Now, researchers led by Lukasz Bugaj of the University of Pennsylvania's School of Engineering and Applied Science have found new ways to modulate cell activity remotely.

A new meta-analysis evaluating condom use across 249 studies and more than a quarter million U.S. teens finds that simply having knowledge about safer sex practices is not enough to encourage condom use. The analysis suggests teens also need to feel confident about buying and using condoms, they need to plan to use them, and they need to be able to communicate effectively with their partners about condom use.

Mites who hitchhike on the beaks of hummingbirds use a surprising method to help them on their journey: electricity.

These hummingbird flower mites feed on nectar and live within specific flowers for their species. When it is time to seek out a new flower, they hitch a ride via hummingbirds, but for years researchers have not been sure exactly how these tiny, crawling arachnids quickly disembark at the right flower. Researchers, including Carlos Garcia-Robledo, associate professor in the Department of Ecology and Evolutionary Biology, are closer to answering these questions, and they published their results in PNAS.