A 2008 view of the leading edge of the Larsen B ice shelf, extending into the northwest part of the Weddell Sea. Huge, floating ice shelves that line the Antarctic coast help hold back sheets of ice that cover land. Mariano Caravaca /Reuters/Landov hide caption

itoggle caption Mariano Caravaca /Reuters/Landov

A simulation from the Neitz lab of what colorblindness looks like, with normal color vision on the left and red-green colorblindness on the right. Courtesy of Neitz Laboratory hide caption

itoggle caption Courtesy of Neitz Laboratory

Safe and small: The credit-card-sized test for anthrax destroys the deadly bacteria after the test completes. Courtesy of Sandia Nation hide caption

itoggle caption Courtesy of Sandia Nation

When combined with results of other neurological tests, and in the context of a thorough medical history, atrophy of the brain (shown here in an MRI scan) sometimes indicates Alzheimer's. Simon Fraser/Science Source hide caption

itoggle caption Simon Fraser/Science Source

Both James Eversull (left) and Pat Patchell were treated with experimental chemotherapy and radiation for leukemia as children in the 1960s. Together, they're now some of the country's oldest leukemia survivors.. Courtesy of James Eversull; Courtesy of Pat Patchell hide caption

itoggle caption Courtesy of James Eversull; Courtesy of Pat Patchell

Johnny Reynolds ignored diabetes symptoms and put off going to the doctor for years when he didn't have health insurance. He was afraid he couldn't afford treatment. Anders Kelto/NPR hide caption

itoggle caption Anders Kelto/NPR