Ancient retroviruses -- distant relatives of the human immunodeficiency virus -- helped a gene called p53 become an important "master gene regulator"in primates, according to a new study.

  Low vitamin D levels may cause greater knee pain and difficulty walking in patients with knee osteoarthritis, according to new research. Knee osteoarthritis is caused by cartilage breakdown in the knee joint. Factors that increase the risk of knee osteoarthritis include being overweight, age, injury or stress to the joints, and family history can increase the risk of knee osteoarthritis.

  Low doses of freeze-dried grape powder inhibit genes linked to the development of sporadic colorectal cancer, researchers found. The study suggests that a diet rich in grapes may help prevent the third most common form of cancer, one that kills more than a half a million people worldwide each year.

  Clinicians have unraveled a connection between the incidence of oral cancer and race and ethnicity -- as part of first epidemiological study of oral cancer in California.

  A research team demonstrated the significant anti-cancer effects of milk thistle. They found that the major biologically active compound of this plant, silibinin, could suppress the growth of cancerous liver cells. These scientists further studied the mechanisms of the anti-cancer effects of silibinin.

  Sometimes it's difficult for us to remember how we felt about a product. A new study reveals that when memory fails, consumers will use postpurchase actions as a proxy. In other words, if we gab about a terrible dinner and a boring movie with loved ones, we might mistake the positive memory of talking about the experience for positive memories of the experience itself.

  While investigating how the hormone orexin might control sleep and hunger, researchers have discovered, to their surprise, that it activates a protein, HIF-1, long known to stimulate cancerous tumor growth.

  A human stem cell line derived from embryos that were identified by preimplantation genetic diagnosis to carry the mutation for fragile X syndrome has provided an unprecedented view of early events associated with this disease. In addition to giving scientists fresh insight into fragile X, results from this unique model system have emphasized the value of this new source of embryonic stem cells and may have a significant impact on the way that genetic diseases are studied in the future.

  Carbon dioxide emissions of 50,000 power plants worldwide, the globe's most concentrated source of greenhouse gases, have been compiled into a massive new data base, called CARMA -- Carbon Monitoring for Action.

  A key mechanism in how cholera bacteria communicate with each other has been discovered. This pivotal breakthrough that could lead to treatments for cholera and other bacterial diseases.

  As world leaders prepare to discuss conservation-friendly carbon credits in Bali and a regional initiative threatens a new wave of deforestation in the South American tropics, new research highlights once again the irreplaceable importance of primary rain forest.

  For some families, the cancer diagnosis of a child strengthens existing religious ties or prompts new ones. Now, a new study reports that while most pediatric oncologists say they are spiritual, and many are open to connecting with the families of very sick children through religion or spirituality, they typically lack the formal healthcare training that could help them build such bridges.

  A supernova observed last year was so bright -- about 100 times as luminous as a typical supernova -- that it challenged the theoretical understanding of what causes supernovae. But astrophysicist Stan Woosley had an idea that he thought could account for it -- an extremely massive star that undergoes repeated explosions. When he worked out the detailed calculations for this model, the results matched the observations of the supernova known as SN 2006gy, the brightest ever recorded.

  A protein measured in a simple blood test may be a new biomarker to identify patients with the most serious form of asthma. Identifying this new biomarker, YKL-40, brings investigators one step closer to a treatment for the nation's 2.5 million asthmatics with a severe form of the disease that is difficult to treat, the researchers say.