Methane on Mars: A sign of life?
The discovery of the organic gas methane on Mars is the strongest evidence yet that life may exist on the Red Planet, says The Washington Post. Methane is the combustible compound that we use to fuel our natural-gas stove tops. The bulk of the methane on this planet is a byproduct of life, manufactured by bacteria and other microbes; cows, humans, and other creatures all emit methane as part of the digestion process. In summertime on Mars, a new NASA study found, pockets of methane under the planet’s crust open up to release about 1.3 pounds of the gas every second. This means there’s a good chance that Mars’ methane, too, is produced by living things under its surface—probably large colonies of bacteria. There’s also the possibility that the methane on Mars has been produced as a result of chemical reactions in its rock: Methane can result from interactions between water and the mineral olivine. Even so, “we believe this definitely increases the prospects for finding life on Mars,” says NASA’s principal investigator Michael Mumma. “No other discovery has done as much to increase the chances of finding life.”
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The robot in your veins
In a real-life version of the sci-fi classic Fantastic Voyage, scientists are working on a tiny swimming robot that would travel through the blood vessels of the human body, taking observations and possibly even performing internal operations. Australian scientist James Friend and his team are developing a prototype that employs nano-sized rotors that drive flagella, the same tail-like structures that propel sperm cells. The nanobot is at this point just an observation bot, but it’s got a bright future. As the project moves forward, Friend tells Agence France-Presse, “we will go for other kinds of operations, mainly snipping and cutting.”
The promise of grape seeds
Grape seed extract holds promise as a potent anti-cancer agent, a new study has found. University of Kentucky researchers found that natural substances called proanthocyanidins found in grape seeds killed 76 percent of leukemia cells within one day without damaging healthy cells. The extract caused the cancer cells “to commit suicide,” said researcher Xianglin Shi. Previous laboratory studies found that grape seed extract also protected against breast, prostate, and skin cancer by causing the cancer cells to die. “What everyone seeks is an agent that has an effect on cancer cells but leaves normal cells alone,” said Shi. “Grape seed extract fits into this category.” More research must be done, he said, to determine if the extract is effective against cancer cells in the body and not just in a test tube.
Dieting at a disadvantage
Women may diet more often than men, but they’re not nearly as good at it, says a new study. To test hunger responses in men versus women, researchers at the Brookhaven National Laboratory asked 23 volunteers to fast for 17 hours. Each participant was then presented with a heaping portion of his or her favorite dish, from pizza to burgers to chocolate cake, and asked to ignore it for 40 minutes. Injected with nuclear tracers and placed in PET scans, volunteers’ brains were monitored as they tried to suppress their hunger. With scientists watching, most of the subjects were able to control their hunger, but the brain scans revealed that in women, there was continuing activity in the amygdala—a region related to strong emotion. In effect, the women could not stop thinking about eating the forbidden food, and felt waves of emotion about being deprived. In men, the cravings faded once they decided not to eat. “We didn’t expect such a striking difference between males and females,” researcher Nora Volkow tells Scientific American.
