- Comet’s 10 Million-Mile Tail Lights Up in Infrared
- Fasting Might Make Chemotherapy More Effective
- Driving Distracts Cellphone Users
- New Lasers Fight Crime, Martians
- New Chemical Diversity Discovered in Old Meteorite
Posted: 17 Feb 2010 11:17 AM PST
NASA's new infrared telescope has released its first images.
The Wide-Field Infrared Survey Explorer has returned more than 250,000 raw images. To celebrate its performance thus far, NASA selected four of them for processing and publication.
Above, you can see the comet, Siding Spring, which was discovered in 2007 by Australian observers. Its 10-million-mile long tail is made of glowing dust pushed away from its nucleus by the solar wind.
WISE launched on Dec. 14, 2009 and took in its first starlight at the end of the month. The telescope is intended to survey the entire sky looking for cosmic oddities. The mission will also provide better data on the average size of asteroids in the solar system, which will refine scientists' estimates of how often a dangerous near-earth object hits the Earth.
WISE is one of three space-based telescopes that observe in the infrared. NASA's Spitzer Space Telescope and the Herschel Space Observatory also look at the longer wavelength side of the electromagnetic spectrum. Because the longer light waves travel more effectively through fine particles, the infrared is best for observing dusty regions.
In the image below, we see the Andromeda galaxy's dusty spiral arms. WISE has four detectors in the infrared spectrum, which measure light with wavelengths of 3.4, 4.6, 12, and 22 microns. By using only the detectors that can measure the longest wavelengths, scientists can generate images like the one below, which shows just the dusty arms of the galaxy, which are heated by young stars.
Posted: 17 Feb 2010 10:32 AM PST
Ashort period of fasting prior to chemotherapy may protect healthy cells but leave cancer cells vulnerable to drugs, according toa new study.
The results are very preliminary, based on animal research and a case study of just 10 people. But if they hold up, doctors could have a new tool for reducing chemotherapy's side effects and safely administering larger doses.
"Side effects aren't just, 'Will I lose my hair or not?'" said Valter Longo, a University of Southern California gerontologist. "It's, 'Will I be able to receive a high dose or not?'"
For the last decade, Longo has studied the effects of caloric restriction on cell function. In lab animals, diets with 25% fewer calories than normal are linked to extended, healthy lifespans. The mechanisms are poorly understood, but it seems that dietary stress activates cell-protecting mechanisms.
Longo's specialty is insulin-like growth factor 1, or IGF-1, a protein that regulates cell growth. Its production is limited during fasting. In yeast and roundworms, inhibiting IGF-1 has produced record lifespans. According to Longo, people who read about his work elected on their own to try fasting before chemotherapy. "We told them not to, their oncologists told them not to, but the patients went ahead and did it," he said.
Their accounts were gathered in a case report published in December in the journal Aging. Of10 patients, six reported fewer side effects when they received chemotherapy while fasting, rather than while consuming food normally. Four received chemotherapy only while fasting, and reported fewer side effects than is typical. The effects of treatment did not appear to be altered at all.
In a paper published Monday in Cancer Research, Longo's team followed the human findings with a study of mice with cancer. Fasting reduced their IGF-1 levels. When given chemotherapy, none of the normal-diet control group survived, while 60 percentof fasting mice lived.
The findings are subject to many caveats. A mouse study is only a mouse study, few people were involved in the human study, and negative results may not have been reported. Still, the results have sparked further interest. In addition to his own ongoing clinical study at USC, Longo said the Mayo Clinic and Children's Hospital of Los Angeles are also planning tests.
Longo also started a company, L-Nutra, to develop a line of chemotherapy-tailored meals.
"I'd never tell patients to keep this in mind, but I'd tell the oncologists," said Longo. "If someone is out of options and suffering terribly, you have to keep in mind things that could make a difference, though there isn't a clinical trial with 2,000 people finished."
Image: Nic McPhee/Flickr
Citations: "Fastingandcancer treatment in humans: Acaseseries report." By Fernando M. Safdie, Tanya Dorff, David Quinn, Luigi Fontana, Min Wei, Changhan Lee, Pinchas Cohen, and Valter D. Longo. Aging, Vol. 1 No. 12, December 31, 2009.
"Reduced Levels of IGF-I Mediate Differential Protection of Normal and Cancer Cells in Response to Fasting and Improve Chemotherapeutic Index." By Changhan Lee, Fernando M. Safdie, Lizzia Raffaghello, Min Wei, Federica Madia, Edoardo Parrella, David Hwang, Pinchas Cohen, Giovanna Bianchi, and Valter D. Longo. Cancer Research, Vol. 70 No. 4, February 15, 2010.
Posted: 16 Feb 2010 04:28 PM PST
Cellphone conversations don't just interfere with driving. Driving dents the capacity to describe and remember cellphone messages, at least for some of the youngest and oldest drivers, a new study finds.
Routine driving impedes a person's ability to relay information from a cellphone call accurately to a conversation partner and to remember key elements of that information, say psychologist Gary Dell of the University of Illinois at Urbana-Champaign and his colleagues. Although many drivers regard talking while cruising a straightaway as no harder than walking while chewing gum, "that intuition is incorrect," Dell says.
Both older and younger drivers seated next to a passenger and operating a vehicle in a simulator had more difficulty correctly retelling brief stories, versus retelling stories while sitting in an unmoving "car," the researchers report in the February Psychonomic Bulletin & Review. Participants, especially those over age 60, remembered less about stories after simulated driving than after sitting in the unmoving car. That might reflect a greater emphasis on defensive driving among older drivers.
Driving skills, such as rapid reactions to approaching vehicles in intersections, also took a hit while retelling the stories, the investigators say. Earlier studies have reported that driving worsens while talking on cellphones or sending text messages.
These new findings challenge the belief that work productivity benefits by conducting important conversations, such as business negotiations, while commuting.
"Safety concerns aside, if the quality of a conversation matters to your business, then it is best to reserve your conversation for times when you are not operating a motor vehicle," remarks psychologist David Strayer of the University of Utah in Salt Lake City. Strayer studies the impact of cellphone use on driving skills.
Dell's team studied 96 pairs of adults, each consisting of a driver and a partner. Half the volunteers ranged in age from 18 to 21; the rest were in their 60s and 70s. Drivers sat in a car facing a projection screen that allowed them to navigate through a virtual city. They were told to drive down a city street and through several busy intersections while obeying a speed limit of 30 miles per hour, staying in the center of the lane and stopping at stop signs.
After an initial trip without talking, drivers on subsequent trips listened to and then retold a series of 10- to 20-second stories heard over a hands-free headphone. Partners did the same during other trips.
In another condition, drivers and passengers listened to and retold stories in an unmoving car. Drivers but not passengers in a "moving" simulator retold a smaller number of central story elements, such as the nature of a robbery. They described nearly 70 percent of story elements correctly in an unmoving car, as did passengers. That figure fell to 60 percent while driving on straightaways and to 50 percent while going through intersections. Passengers' accuracy at retelling stories remained the same regardless of condition.
Story retelling in the new study roughly corresponds to a driver or passenger listening to a half-minute podcast or cellphone message and then relaying that information along, Dell says. Actual driving presents dangers that divert attention from what's said more than virtual driving does, he adds.
Posted: 16 Feb 2010 03:26 PM PST
A new technique that uses a laser to vaporize materials like rocks and steel to analyze their chemical composition is finding new applications from Mars to forensics.
Thanks to its relatively small size and low cost, laser-induced breakdown spectroscopy is emerging from the laboratory and turning into a precise tool for figuring out what something is made of. What had been a technique largely for scientists now can be transformed into a tough, small system that can be operated by a technician instead of a PhD.
"The same things that make it amenable to go to Mars also make it amenable to go out in the field," said Jose Almirall, a chemist at Florida International University who has a grant from the Department of Justice to explore how crime labs can use the technology.
NASA will be deploying a LIBS system called the "ChemCam" on its new Mars rover, now named Curiosity and scheduled to launch next year.
LIBS works by blasting a material with a high-energy laser pulses. The Mars Curiosity rover will send an average of three pulses a second, each one 5 nanoseconds long. The power during that pulse is in the range of 10 megawatts.
That's not enough to shoot a hole in your hand, but it'll leave a mark.
"I've shot myself and you might see a little spot where you shot yourself, if it's just one laser shot," said Roger Wiens, a space scientist at Los Alamos National Laboratory, who developed the ChemCam for the Mars Curiosity mission.
In some cases, the ChemCam will be focused on rocks for more than 15 seconds. If you were to do that to your arm, "You'd be in pain," Wiens said.
There are no plans to use the laser for anything but science, but there's something science-fictionally satisfying about the next Mars rover coming equipped with a laser "gun."
The laser shots vaporize a crater less than a millimeter across, turning its molecules into a 14,000-degree plasma. The atoms are shorn of their electrons, but as the plasma ball cools down, they return to a more normal state. The electrons drop into their orbits around the nucleus and as they do so, the little plasma ball emits light.
"You can see it with your eyes and it makes a little zapping sound when you do it," said Wiens.
The specific color of the light tells scientists exactly what element they are looking at if they pass it through a spectrometer, which can precisely measure the wavelength of light.
Lasers have been used to create small clouds of atoms for spectral analysis in the past, but those systems require a separate torch that heats the atoms into a plasma. With LIBS, the same laser blast does both jobs. It's this simplicity that could aid the technology's spread. A 2004 Cambridge University Press book on LIBS declared the technique "perhaps the most versatile method yet developed for elemental analysis."
On Earth, there are plenty of times when one might want to know the very precise composition of a substance. In late 2009, for the first time, a LIBS analysis was used in a court. It helped identify a would-be bank robber by the glass on his clothing in Maryland. After being locked in a vestibule by secret alarms, he shot his way out and sped away. After being apprehended, some pieces of glass were found on his clothes. When Almirall's team compared the precise composition of that glass with the stuff from the bank, they came back with a probable match.
Glass made in different places and at different times is quite distinctive at the molecular level, Almirall said. In modern manufacturing processes, sodium carbonate and calcium oxide are usually added to the base silica. But tiny amounts of other elements such as strontium can act as a particular type of glass' signature. The older a glass-manufacturing plant is, for example, the more zirconium leaches into the glass melt.
The level of precision that LIBS can offer may eventually help manufacturers do quality control on their products. Almirall is even thinking about how to use a briefcase LIBS system to test products for U.S. Customs to ensure their safety and provenance.
"If you were receiving some toys and want to immediately know if you have lead in these toys, LIBS could do that very quickly," Almirall said. "Green light, no lead. Red light, there is lead."
Several companies are trying to commercialize LIBS systems including Applied Spectra of Fremont, California, and Stellar Net of Tampa, Florida. Stellar Net's PortaLibs is shown above. Clearly, the technology has gone a long way toward fulfilling the promise Wiens first saw in it 13 years ago.
"I was looking for other technologies to put into space and a colleague here [at Los Alamos Lab] took me to his laboratory and showed me a little laser the size of a cigar and a rock across the room and a little transistor battery," Wiens recalled. "He had the laser hooked up to the 9-volt battery, charged up some capacitors for a few seconds, and then zap, across the room, there was a spark."
Posted: 16 Feb 2010 10:04 AM PST
A new analysis of an ancient meteorite that fell to Earth in 1969 reveals millions of complex compounds, underscoring the richness of our galaxy's primordial soup.
More than 200 pounds of the meteorite were recovered from its crash site in Murchison, Australia in 1969. Subsequent analysis classified it as a carbonaceous chondrite: a rock that formed in the early solar system's mix of gas and dust, floating for billions of years until finding our planet.
Researchers found hundreds of molecules in the carbon-rich rock, including amino acids produced in the famous Miller-Urey experiments, thought to simulate the conditions that spawned life. But those scientists were limited by their era's relatively rough methods, and tended to look for what they expected to find.
In a study published Monday in the Proceedings of the National Academy of Sciences, researchers turned the latest chemical analysis tools to a piece of the Murchison meteorite. Using techniques that measure mass down toa single electron, they found more than 14,000 different molecules.
These can be combined in millions of different configurations, hinting at a wealth of molecular possibilities on early Earth and elsewhere in the solar system.
"Extraterrestrial chemodiversity is high compared to terrestrial relevant biogeological and biogeochemical-driven chemical space," write the authors.
In other words, there's far more out there than we've found down here.
Image: A piece of the Murchison meteorite/©Meteorites Australia
Citation: "High molecular diversity of extraterrestrial organic matter in Murchison meteorite revealed 40 years after its fall." By Philippe Schmitt-Kopplin, Zelimir Gabelica, Régis D. Gougeon, Agnes Fekete, Basem Kanawati, Mourad Harir, Istvan Gebefuegi, Gerhard Eckel, and Norbert Hertkorn. Proceedings of the National Academy of Sciences, Vol. 107 No. 7.
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