DNA of the common black rat has shed light on the ancient spread of rats, people and diseases around the globe. Studying the mitochondrial DNA of 165 black rat specimens from 32 countries around the world, a scientists have identified six distinct lineages in the black rat's family tree, each originating from a different part of Asia.

  Adults who were abused as children have about half the symptoms of moderate to severe depression if they have certain variations in a specific gene, compared to people with different variations in the same gene. The gene makes a receptor, on brain cells, for a stress-related hormone. The variations were protective in two separate studies, one mostly of African Americans and the other of whites, across socioeconomic levels.

  Theoretical physicists are suggesting how thin spouts of magma in the Earth's mantle can persist long enough to form hotspot volcanism of the type that might have created the Hawaiian Islands.

  Genetic mutations in the Toll-like receptor 4 gene appear to have significant association with inflammatory injury to the placenta and developing baby, researchers from the University of Pittsburgh's department of obstetrics, gynecology and reproductive sciences report. "This indicates a possible genetic predisposition to a kind of misfire in immune system response that could contribute to placental inflammation and spontaneous preterm birth," researchers said.

  Patients with diabetes, cardiac problems, kidney disorders or high blood pressure could benefit from the development of new hologram technology. The new "smart" holograms, which can detect changes in, for example, blood-glucose levels, should make self-diagnosis much simpler, cheaper and more reliable.

  Approximately one-third of popular songs include reference to explicit drug, alcohol or tobacco use, although this portrayal varies widely by musical genre, according to a new report.

  In an achievement some see as the "holy grail" of nanoscience, researchers have for the first time used DNA to guide the creation of 3-D, ordered, crystalline structures of nanoparticles. The ability to engineer such 3-D structures is essential to producing functional materials that take advantage of the unique properties that may exist at the nanoscale -- for example, enhanced magnetism, improved catalytic activity, or new optical properties.

  Heavy marijuana use has been found to contribute to gum disease, apart from the known effects that tobacco smoke was already known to have. In a group of more than 900 New Zealanders, smoking cannabis more than 40 times a year since age 18 was found to be responsible for more than one-third of the new cases of periodontal disease between ages 26 and 32, according to a new study.

  The continuous fabrication of complex, 3-D nanoscale structures and the ability to grow individual nanowires of unlimited length are now possible with a new process. Based on the rapid evaporation of solvent from simple "inks," the process has been used to fabricate freestanding nanofibers, stacked arrays of nanofibers and continuously wound spools of nanowires. Potential applications include electronic interconnects, biocompatible scaffolds and nanofluidic networks.

  Four days' exposure to a REM sleep deprivation procedure reduces cell proliferation in the part of the forebrain that contributes to long-term memory of rats. REM sleep deprivation was achieved by a brief treadmill movement initiated by automatic online detection of REM sleep. A yoked-control (YC) rat was placed in the same treadmill and experienced the identical movement regardless of the stage of the sleep-wake cycle.

  Squeeze a crystal of manganese oxide hard enough, and it changes from an electrical insulator to a conductive metal. Researchers use computational modeling to show why this happens. The results represent an advance in computer modeling of these materials and could shed light on the behavior of similar minerals deep in the Earth.

  Male chimpanzees hunt in groups, but among the group, certain chimpanzees are "impact hunters" that lead the group to hunt. They are more likely to initiate a hunt, and hunts rarely occur in their absence, according to a new study. The findings shed light on how and why some animals cooperate to hunt for food, and how individual variation among chimpanzees contributes to collective predation.

  People with unrelenting pain are often depressed, anxious and have difficulty making simple decisions. Researchers have identified a clue that may explain how suffering long-term pain could trigger these other pain-related symptoms. Researchers found that in people with chronic pain, a front region of the cortex associated with emotion fails to deactivate when it should. It's stuck on full throttle, wearing out neurons and altering their connections.

  Two novel proteins appear to have the potential to enhance the production of antibodies against a multitude of infectious agents. The researchers are working to develop a safe and effective method to deliver the immune-enhancing molecules to the body's mucous membranes -- the first line of defense against most pathogens -- to elicit protective immune responses on those membranes.