Startup Pixie Scientific is developing a baby's diaper that doubles as a medical diagnostic tool. As The New York Times reports, the company bills its "digital diaper" as something that can spot everything from kidney problems to dehydration and possible urinary tract infections. Several colored squares in the diaper respond to bacteria, water content or protein, and they change color if things become abnormal. An accompanying smartphone app allows for a parent to take a picture. It makes detailed readings of the color changes and then uploads the information to a physician. Blog (sub. req.)