With a lot of skillful maneuverings, a team of researchers have finally found a way to image a molecule. The portrait of pentacene, an organic molecule consisting of five benzene rings, shows off the chemical bonds between the carbon and hydrogen atoms.
It may seem a somewhat surprising first, since atoms have been imaged for decades. The earliest pictures of individual atoms were captured in the 1970s by blasting a target – typically a chunk of metal – with a beam of electrons, a technique known as transmission electron microscopy (TEM)…. But strange though it might seem, imaging larger molecules at the same level of detail has not been possible – atoms are robust enough to withstand existing tools, but the structures of molecules are not [New Scientist].
In the new study, published in Science, researchers used an atomic force microscope to image the molecule in unprecedented resolution. The measurement requires extremes of precision. In order to avoid the effects of stray gas molecules bounding around, or the general atomic-scale jiggling that room-temperature objects experience, the whole setup has to be kept under high vacuum and at blisteringly cold temperatures [BBC News]; 5 Kelvin, to be exact. Rather than relying on an optical system to produce pictures, atomic force microscopes use a probe that narrows to an atomic-scale tip, and measures the forces of attraction between the tip and the molecule’s components.
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Watermelons could do more than grace the tables at picnics across the land: They could also serve as a source of biofuel. Researchers fermented watermelon juice to produce ethanol, according to a study published in Biotechnology for Biofuels, and while the melons aren’t likely to become a primary biofuel crop, the process could help out farmers.
Nearly one-fifth of the watermelon crop grown in the United States is left in the fields after harvest because of defects on the melons’ rinds. “It’s not that there’s anything wrong with the melon on the inside, but our only method of judgment is the outside,” said [lead author] Wayne Fish [Greenwire]. Although farmers often till the abandoned melons into the soil, the value of the nutrients provided by this practice is much less than the overall cost to farmers of losing so much of their crop.
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In a doctor’s office in the near future, part of a smoker’s routine checkup could involve blowing into a tube connected to a small sensor. The doctor will look at the sensor’s display and know immediately whether she has to deliver the grim diagnosis: lung cancer. Researchers in Israel have invented a new “breathalyzer” that can detect chemical compounds produced by lung cancer cells. The finished device should be portable and inexpensive and provide a faster, easier, and more sensitive way to screen for tumours than X-rays or blood tests. Such screening should help doctors detect cancer early, when it’s most treatable [Telegraph].
The new device, described in Nature Nanotechnology, is not the first to find evidence of cancer on a person’s breath. Other attempts to do this have yielded promising results, … but those devices require a higher concentration of the telltale biomarker chemicals than the Israeli device. The chemicals, called volatile organic compounds (VOCs), are metabolic products present in the vapors that we breathe out, but they occur in such small amounts that researchers have had to find ways to increase their concentrations before testing [Technology Review]. But the new sensor has such sensitivity that it can detect traces of the compound in their natural concentrations in human breath, and it can therefore give results immediately, without processing and analyzing the sample in a lab.
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India’s first lunar mission has ended not with a bang, but with dead silence. India‘s space agency lost contact with the lunar orbiter, Chandrayaan-I, over the weekend; when efforts to restore communication were futile Indian officials declared that the mission was over.
The launch of Chandrayaan-1 in October 2008 put India in an elite club of countries with moon missions. Other countries with similar satellites are the United States, Russia, the European Space Agency, Japan and China [AP]. Indian officials hope that either NASA or the Russian space agency will agree to track the orbiter, which is currently circling 125 miles from the moon’s surface. The satellite’s orbit will slowly decay over the next several years, and it is expected to crash into the moon in about 1,000 days.
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The pale-coated deer mouse that makes its home in Nebraska’s Sand Hills prairie has become a poster-mouse for evolution, based on results of a study published in Science.
The rodent typically has dark fur (bottom photo), but one Nebraska group of mice evolved to have lighter fur (top photo) after the Sand Hills formed 8,000 to 15,000 years ago. A lighter coat is advantageous because it allows the animal to blend in with its pale surroundings. But what’s more amazing is that before the formation of the Sand Hills, the deer mouse didn’t even possess the gene that controls coat color in the rodents.
The gene, which is known as Agouti, first appeared in deer mice in the Sand Hills about 4,000 years ago; after that, a mutation occurred that gave rise to the mouse’s sandy fur. “The light gene wasn’t in existence, so the mice had to “wait” until a particular mutation occurred and then selection had to act on that new mutation… It’s a two part process. First the mutation has to occur and second, selection has to increase its frequency” [BBC News], said co-author Hopi Hoekstra.
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Image: Emily Kay
Biology Letters, August 23
A fossilized feather has proved that birds had already developed fancy plumage 40 million years ago. Using scanning electron microscopy, researchers examined tiny structures on the feather and determined them to be melanosomes, the organelles inside pigment cells that determine coloration. The organization of the melanosomes resembled patterns seen in the iridescent feathers of birds like starlings and grackles, according to the study. This finding is just the latest progress from a team working to discover the colors of prehistoric birds and even feathered dinosaurs.
Proceedings of the National Academy of Sciences, August 25
In a study that probably provoked fierce debate in text messages, emails, and blogs simultaneously, researchers found that people who frequently multitask are actually bad at multitasking. The researchers expected multitaskers to be better than average at organizing information and switching between tasks quickly, but found just the opposite. Elsewhere in the journal, researchers examined the genome of honeybees and offered a partial explanation of colony collapse disorder. The study suggests that a variety of viruses are damaging the bees’ ability to make proteins that are needed to protect them from all the other slings and arrows of the world, like bacterial infections and food shortages. While this is an incremental step towards understanding what is destroying honeybee hives around the country, every little bit helps.
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A week-and-a-half after the first-ever human clinical embryonic stem cell trial was put on hold, Geron Corp. announced why: microscopic cysts that arose in laboratory animals but did not spread to other locations in the animals’ bodies.
In January, the FDA granted the company permission to begin using its stem cell treatment on patients with spinal cord injuries–but then the trial was delayed before the first patient could be enrolled. Although cysts developed occasionally during previous animal trials, they occurred more frequently in the more recent experiment. Geron was quick to point out, however, that the cysts were small and did not appear to be harmful in any way. In fact, the statement pointed out, cysts are not uncommon in victims of spinal cord injury, developing in the spinal cord scar tissue in up to 50% of patients [The Scientist]. In addition, the cysts did not develop into teratomas, a type of tumor that develops from pluripotent stem cells.
Geron said the company is working with the FDA to investigate the issue, and company officials are confident that the trial will soon be back on track. The FDA offered no comment regarding Geron’s announcement, saying they “neither confirm nor comment on clinical holds” [The Scientist].
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Image: iStockPhoto
Another day, another swine flu story: Amidst all the chatter, it can be hard to find the most reliable sources and relevant info. To keep you informed of the latest intelligence, 80beats will round up the news each week.
On Monday, the President’s Council of Advisors on Science and Technology issued an alarming report spelling out a “plausible scenario” for how the swine flu pandemic will play out during the coming flu season. The report estimated that the H1N1 virus could hospitalize 1.8 million Americans, potentially clogging emergency rooms and intensive care wards, and could kill up to 90,000 people in the United States. In a typical year, the seasonal flu virus kills about 35,000 Americans.
But on Tuesday, some public health officials walked back the report’s conclusions. One expert who helped prepare the report said that the numbers were probably on the high side, given that some weeks had passed since the calculations were finished in early August. “As more data has come out of the Southern Hemisphere, where it seems to be fading, it looks as if it’s going to be somewhat milder,” said the expert, Marc Lipsitch…. “If we were betting on the most likely number, I’d say it’s not 90,000 deaths; it’s lower” [The New York Times].
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In an attempt to steer organ donation away from organs purchased on the black market or harvested from executed prisoners, China has announced a system to coordinate voluntary organ donation. The details of the new system are still under development, according to Chinese officials.
Although China is far from the only country facing a shortage of donor organs, the number of people who plan to donate is astoundingly low–since 2003, only 130 people have pledged to give up their organs after they pass away. Chinese officials estimate that 1.5 million Chinese need transplants annually but only 10,000 are performed due to donor shortages [The Wall Street Journal]. Of the transplants performed, officials estimate that at least 65 percent use organs from executed prisoners.
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The remarkable diversity among dogs‘ coats–from the shaggy fur of a sheepdog to the sleek coat of a beagle, and everything in between–comes down to a mere three genes, according to a new report published in Science. The broad genetic study determined that one gene controls hair length and softness, another determines whether the hair is straight or curly, and a third controls the pattern in which hair grows, so that dogs with a particular version have wiry hair and moustaches and long facial details known to breeders as “furnishings”…. The combinations in which these genes are inherited then determine a dog’s overall look [The Times].
To reach these conclusions, the researchers first looked at the genetic differences within single breeds that have more than one coat type. Purebred dogs are particularly suited for this kind of study, Dr. Ostrander said, because they have been selectively bred to segregate traits — there are long- and short-haired dachshunds, for example [The New York Times]. By analyzing the genomes of two dachshunds with different types of coats, the researchers were able to determine which gene was linked to the variation in hair length. Similar studies revealed the other two genes.
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Nitrous oxide, also known as laughing gas, might sound like a humorous substance. But here’s a sobering fact: The chemical now poses the largest man-made threat to the ozone layer, according to a study published in Science. Environmental policies, which have focused on controlling emissions of compounds such as CFCs, have largely ignored nitrous oxide. CFC levels have been falling since the 1989 adoption of the Montreal Protocol on Substances that Deplete the Ozone Layer… Meanwhile, nitrous oxide levels have been climbing as a result of increased emissions from agricultural fertilizers, biomass burning and animal waste [Nature News].
Researchers used a model to compare the potential of various gases, including laughing gas, to deplete the ozone layer, compared to a compound called CClF3, a substance with one of the greatest potentials for destroying the ozone. They found that although the threat that nitrous oxide poses to ozone is small compared to CClF3, the large-scale emissions of laughing gas mean it is the most significant of the ozone-depleting substances emitted by human-related activities today…. “This is the first time someone has dealt with nitrous oxide in isolation like this,” says atmospheric chemist Susan Solomon. “It’s one of those things that has simply been overlooked” [Nature News].
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Image: iStockPhoto
Amidst concerns over the safety of DEET, scientists are on the lookout for a new mosquito repellent. Now they may have found a way to keep biting insects at bay–by blocking their olfactory sense, according to a paper published in Nature.
Mosquitoes sense the presence of humans and animals by detecting the carbon dioxide we exhale with each breath. Researchers have found two compounds, 2,3-butanedione and 1-hexanol, that could keep the biters at bay by blocking the insects’ ability to detect this gas. Using these compounds could be advantageous because the amount of chemical required is relatively small…. Further, the chemicals themselves are not complicated to manufacture and are available through conventional sources. “From both perspectives, this adds up to a viable tool in tackling the problems like that of malaria in Africa” [Scientific American], says study coauthor Anandasankar Ray. Considering the number of diseases spread by insects such as mosquitoes–for example, 250 million people contract malaria each year–there’s a lot more at stake here than a few itchy bug bites.
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Medical imaging tests such as CT scans are valuable diagnostic tools, but their increasing use in doctors’ offices and hospitals is providing a sizable dose of radiation for about 4 million Americans under the age of 65. About 400,000 of those Americans receive very high doses, more than the maximum annual exposure allowed for nuclear power plant employees or anyone else who works with radioactive material [The New York Times], according to a study published in The New England Journal of Medicine.
Researchers based their estimates on a study of almost 1 million people between the ages of 18 and 64 who they followed for almost three years, and found that nearly 70 percent of test subjects were subjected to at least one procedure that would have exposed them to radiation. Although the study didn’t examine whether this radiation could cause an increase in cancer rates, some experts believe it would probably result in tens of thousands of additional cancers…. Each individual patient is at relatively minor additional risk from the tests, [researcher and cardiologist Rita] Redberg said, but because they are given to so many people, the cumulative risk is significant [The New York Times].
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The most practical and immediate steps we can take to slow global warming may be lining roadways with towering “artificial trees” and covering buildings with algae bioreactors, argues a new report from Britain’s Institution of Mechanical Engineers. The group believes that geoengineering (a broad term for climate-altering technologies) may be necessary to reduce carbon dioxide levels immediately, while governments continue to bicker about how to transition to a low-carbon future. “Geo-engineering is no silver bullet, it just buys us time,” said Tim Fox of the IME, who led the study [The Guardian].
Fox says the study (pdf) looked for techniques that could be rolled out with existing technology. The IME’s first suggestion is to construct hundreds of thousands of “artificial trees”, essentially building- or goalpost-sized structures through which the wind blows. As air passes through them, the “trees” extract CO2 from it for later sequestration [The Register]. The fake trees are intended to be much more efficient at absorbing CO2 than real, biological trees, with current designs estimated to remove one ton of CO2 from the air daily. But even if the devices could be made ten times more efficient, the study found that 100,000 fake trees would be required to absorb the CO2 emissions from all the cars and trucks in the United Kingdom.
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In a star system 330 light years away from Earth, astronomers have spotted a giant planet that booms around its parent star in tight, fast circles, completing an orbit (the planet’s “year”) in less than one Earth day. The exoplanet, known as Wasp-18b, is so close to its star that researchers say it appears to be spiraling inwards to its fiery doom. But the odds of seeing a planet in its death throes are so low that researchers are searching for alternate explanations, and say the planet could force scientists to rethink established ideas about planetary forces known as tidal interactions [National Geographic News].
The planet is known as a “hot Jupiter,” meaning that it’s a massive gas giant like our own solar system’s Jupiter, but it orbits in close proximity to its star. Current theories say that such a massive planet so close to its star should be pulling on the host star, creating a tidal effect similar to the moon’s pull on Earth. At that range the planet’s pull would be so strong that it would drain energy from its orbit, causing the planet to rapidly fall into the star [National Geographic News]. But if that’s the case, the planet would meet its death in less than a million years. Since the star system is thought to be about 1 billion years old, the odds of catching the planet in its last stages are one in a thousand.
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