Washington, DC - Circuits in the brain act as an internal clock to tell us it is time to sleep and to control how long we then stay asleep. A new study in flies suggests a part of that clock constantly monitors changes in external temperature and integrates that information into the neural network controlling sleep. The study was published in Nature and was supported by the National Institute of Neurological Disorders and Stroke (NINDS), a part of the National Institutes of Health.

Dallas, Texas - When heart failure patients receive a heart pumping device known as a left ventricular assist device (LVAD), their caregivers seem to suffer, too – at least initially, according to research in Journal of the American Heart Association (JAHA), the Open Access Journal of the American Heart Association/American Stroke Association.

Yuma, Arizona - Whitening toothpaste can appear to whiten teeth slightly by removing surface stains, such as those caused by drinking coffee or smoking. However, whitening toothpastes can't change the natural color of your teeth or lighten a stain that goes deeper than a tooth's surface.

Phoenix, Arizona - Colon cancer is cancer of the large intestine (colon), which is the final part of your digestive tract. Most cases of colon cancer begin as small, noncancerous (benign) clumps of cells called adenomatous polyps. Over time some of these polyps can become colon cancers.

Yuma, Arizona - Millions of people traveling internationally experience traveler's diarrhea every year. And, during spring break, that number is especially high for Americans, who may have symptoms ranging from mild to severe, as they travel to countries with warmer climates. But there are some steps you can take to ensure that your trip isn't interrupted by unpleasant bathroom breaks. Jason Howland has more in this Mayo Clinic Minute.