Nature: Although the function of prions—commonly associated with “mad cow disease”—is still unknown, they can also be beneficial to the developing brain. Prions occur in two main forms: normal or misfolded. The normal version, called cellular prion protein, is present in all tissues throughout the body, including neurons. To learn more about their function, researchers in Italy studied the brains of mice, both healthy animals and ones that had been genetically engineered to lack the prion protein, writes Mo Costandi for Nature. By electrically stimulating cells in hippocampus tissue sliced from both sets of animals, the researchers determined that in healthy mice the neuronal connections were strengthened and in the genetically engineered mice the neuronal connections were weakened. Further research is needed to better understand the function of prions and to see whether they serve key functions in other parts of the brain, such as the visual cortex.
Daily Archives: February 15, 2013
FDA approves first retinal prosthesis
Wall Street Journal: The Argus II is a treatment option for people who suffer from retinitis pigmentosa. The genetic disorder destroys the light-detecting cells in the retina, causing vision to blur and then fail. About 100 000 people in the US have been diagnosed with the condition. The Argus II, which is already available for patients in Europe, can significantly improve vision quality, but it cannot completely restore sight. The device bypasses the damaged cells by wirelessly transmitting video from a camera mounted on the user’s glasses to a retinal implant. That signal triggers electrodes to stimulate light pixels in the retina, which the brain interprets as black-and-white images. The device is very useful for reading large letters but not very effective at recognizing small details. The scientists who developed the Argus II hope that future versions will have increased resolution and the ability to create color images.
Uncertainty principle demonstrated at macroscopic scale
Science News: Werner Heisenberg’s uncertainty principle is a central tenet of quantum mechanics. It states that one can’t have precise knowledge of both the position and momentum of a particle: Any method of measuring one of the two values for a particle would change both. Now Thomas Purdy and his colleagues at JILA in Boulder, Colorado, have demonstrated that the principle also holds true at the macroscopic level. The researchers created a drum by stretching a flexible silicon nitride skin across a frame 0.5 mm to a side, placed the drum between a pair of mirrors, and cooled the system to 4 K. They then shot a laser through the drum so that the photons bounced back and forth between the mirrors. The photons transferred momentum to the drum before entering a detector that calculated the drum’s position. The picometer-sized vibrations that resulted in the drum were in strict agreement with Heisenberg. Similar setups, albeit on a larger scale, are being used in an attempt to detect gravitational waves. The work of Purdy’s group will be useful for calibrating those instruments.
Russia suffers rare meteor strike
BBC: Earlier today a meteor struck in the Ural Mountains of central Russia. People reported seeing a fireball streaking across the sky about 9:20am local time, followed by loud bangs. According to officials, the meteor weighed about 10 tons and was traveling at least 54 000 km/h when it entered Earth’s atmosphere and shattered into fragments. Most affected was the region of Chelyabinsk, where a large fragment landed in a lake, sending a shockwave that broke windows and shook buildings in nearby towns. More than 900 people were injured; most suffered minor cuts and bruises, but dozens had to be hospitalized. Scientists say there is no link between the meteor strike and asteroid 2012 DA14, which is expected to fly past Earth later today.