San Diego State University

Fresh air might not be quite as fresh as we think. Viruses and bacteria get swept up into the atmosphere in enormous amounts, and now a new study has quantified that amount, finding that untold billions of microorganisms are raining down across the Earth every day.

A gene called Pim1 may give some kinds of cancer much of their potency, but it could also save your heart. Researchers found that heart progenitor cells modified to over-express Pim1 lived longer and divided more prolifically, causing the heart to self-repair more readily with age.

Researchers at San Diego State University have discovered a new human immune system.