The invention of the microscope allowed scientists to peer into the tiniest of cells. Now, imagine a device that can not just look into minute cells, but can also listen in on their activities.
A team of scientists is building a “micro-ear” that uses tiny beads and lasers to amplify and measure vibrations on a molecular scale. The team hopes the new device will become standard lab equipment soon, allowing scientists to listen to the movement of bacteria such as E. coli as well as microorganisms that cause diseases like sleeping sickness [The Daily Beast].
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Bats and dolphins are two of the most celebrated users of echolocation, employing high-frequency sounds to locate prey, find their way, or to communicate. Now a new set of findings in Current Biology show that not only do the two different kinds of mammals use the same method, they also evolved nearly the exact same molecular means for hearing at high frequencies.
That second part was a surprise, study author Stephen Rossiter says: “It’s common on a morphological scale but it’s assumed not to occur at a DNA level because there are so many different ways to arrive at the same solution” [BBC News]. That is, while it’s quite common for different species to separately evolve similar features—like the tusks of elephants and walruses—it’s quite unlikely that natural selection working in separate species would settle an essentially identical gene and protein for growing tusks, hearing high-frequency sounds, or anything else. Or so the thinking went.
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Tinnitus, the perceived ringing and buzzing in one’s ears, may not be fully understood, but what is known is that it can severely disrupt a person’s life. Treatment for the condition has been unreliable, but now scientists are reporting a new way to turn down the ringing by turning up music, according to a new study.
Scientists altered participants’ favourite music to remove notes which matched the frequency of the ringing in their ears. After a year of listening to the modified music, individuals reported a drop in the loudness of their tinnitus [BBC News]. Participants who listened to music in which notes of a different frequency were removed reported no such improvement. The treatment could be a cheap way to help the three percent of the population that suffers from tinnitus, say the researchers, who published their findings in the Proceedings of the National Academy of Sciences.
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A new study comparing Americans’ vision today to what it was like nearly 40 years ago says that our nation’s eyesight is getting worse as myopia, or nearsightedness, continues to become more prevalent. The study, led by Susan Vitale, appears in the Archives of Ophthalmology.
Vitale and colleagues used data from the National Health and Nutrition Examination Survey (NHANES) to compare the percentage of black and white Americans aged 12 to 54 with myopia in 1971-1972 and 1999-2004 [Reuters]. In the early 1970s only a quarter of people were nearsighted, but by the study’s 1999 to 2004 window that number had shot up to 42 percent.
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Sharks and humans seem more and more alike with each new scientific find. Not only do some sharks have hunting patterns that resemble those of serial killers, but now scientists have discovered that the hammerhead shark’s distinctive head shape allows it to see like a human.
Binocular vision occurs when the fields of two eyes overlap, allowing the accurate perception of depth and distance. It is especially important for predators which need to judge the distance to their prey [BBC News]. Researcher Stephen Kajiura, a sensory biologist, suggests that the stereo vision helps the sharks hunt prey like squid that dart around in three dimensions. The wide set eyes also allow the sharks to see through 360 degrees of vision, according to the researchers, who published their findings in The Journal of Experimental Biology.
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The nose knows when you’ve walked into a library or archive populated by books of a certain age: The distinctive musty smell of the old paper fills the halls and reading rooms. Now, for a study in Analytical Chemistry, a research team has analyzed the chemicals that combine to form the “old book smell,” and says that one day a book’s odor could tell scholars a lot about the tome’s history.
The international research team, led by Matija Strlic from University College London’s Centre for Sustainable Heritage, describes that smell as “a combination of grassy notes with a tang of acids and a hint of vanilla over an underlying mustiness. This unmistakable smell is as much part of the book as its contents,” they wrote in the journal article [BBC News]. The smell is a result of volatile organic compounds that are released as the paper ages.
After watching conservators smell the paper while investigating old books, Strlic applied a “sniff test” based on gas chromotography-mass spectrometry to sort out the chemicals mingling in the odors of 72 older documents. The researchers identified 15 organic compounds that made good markers to track the condition of books [Scientific American]. The system isn’t ready for librarians or conservators yet, but Strlic says he envisions a hand-held model they could use to analyze the age of a book, or what materials constitute its pages and binding, in a noninvasive way. Currently, age-testing a book usually requires snipping off pieces for testing.
The sooner the better, because books aren’t forever. Paper produced until about 1850 was made to last for millenniums. The development of new wood-pulping techniques in the middle of the 19th century and the use of rosin sizing reduced the longevity of paper. The acidity of paper made with these techniques causes them to degrade more quickly than the older papers — or newer ones made with different methods after 1990 [Wired.com].
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Image: flickr / Guldfisken
Contact lenses provide a number of convenience advantages over glasses, but one they come up short in one area—you can’t get contacts that automatically adjust to the sun’s UV light and darken, like the photochromic lenses many bespectacled people enjoy. But that could soon change: Researchers in Singapore led by Jackie Ying have now created a contact lens that responds to UV light.
Transition lenses for glasses are coated with a dye that is transparent when out of the sun, but responds to UV light by changing shape and darkening. Few previous attempts have been made to design transition contact lenses, largely because it’s difficult to apply dye coatings uniformly to the delicate, soft surface of a contact lens. Ying and her colleagues got around this by developing a contact lens that embeds dyes uniformly throughout the material [Technology Review].
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Curvis Bickham spent eight months in prison for a triple-homicide because a police dog confused his scent with that of the killer. Now Bickham and others who spent months in jail after dogs linked their scents to evidence from crimes they did not commit are filing a lawsuit claiming Texas authorities falsely arrested and imprisoned them, their attorney said Tuesday [AP]. In a scent lineup, dogs sniff items found at a crime scene, and then sniff jars swabbed with the suspects’ scents and the scents of others not involved in the crime. When the dogs link crime scene and suspect, that evidence is often relied on heavily in court by the prosecution. Alaska, Florida, New York and Texas all use scent lineups to link suspects to crimes.
Dogs are used all the time to fight crime—from sniffing out bombs and drugs to locating dead bodies. However, scent lineups have critics barking. They say the lineups are poorly controlled, and argue that avoiding cross-contamination is basically impossible. The main target of the current lawsuit is Fort Bend County Deputy Keith Pikett—whose home-trained bloodhounds identified the suspects. A 2004 F.B.I. report warned that dog scent work “should not be used as primary evidence,” but only to corroborate other evidence. In several of the cases that were based on Deputy Pikett’s dogs, however, the scent lineups appear to have provided the primary evidence, even when contradictory evidence was readily available [The New York Times]. Deputy Pikett, by his own estimation, has conducted thousands of scent lineups.
The three men who filed the lawsuit against Deputy Pickett were all eventually set free after contradictory evidence proved their innocence. The Innocence Project of Texas, a legal defense organization … released a report last month that excoriated dog scent lineups as a “junk science injustice” [The New York Times]. Dog scent lineups bring to mind another high profile forensic science debate in Texas that many believe led to the execution of an innocent man. Now that the science behind dog scent lineups is coming under the same scrutiny, one can’t help but wonder if scent lineups might have led to a similar outcome.
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Image: flickr / contadini
Some migratory birds that have to navigate across continents have an extremely useful tool at their disposal–an internal compass that points unerringly towards magnetic north. Researchers already knew that some birds possess these biological compasses, but their mechanism has been unclear. “This is basically the sixth sense of biology, but no one knows how it works…. The magnetic sense is by far the least understood sense in the natural world,” [Science News], says study coauthor Henrik Mouritsen.
Now, researchers have determined that light-sensing cells in the eye convey the crucial message to a special visual center of a robin’s brain, called cluster N. Special proteins called cryptochromes in the birds’ eyes may mediate this light-dependent magnetic sensing, Mouritsen says. Light hitting the proteins produces a pair of free radicals, highly reactive molecules with unpaired electrons. These electrons have a property called spin which may be sensitive to Earth’s magnetic field. Signals from the free radicals may then move to nerve cells in cluster N, ultimately telling the birds where north is [Science News].
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Phantom limb syndrome is an eerie condition, in which amputees have the physically painful sensation that their missing limbs are still present. Now, a small new study has shown that people can twist those ghostly limbs in anatomically impossible ways, while still feeling that the limb is real and present. In essence, each amputee’s brain reshaped his understanding of where his body was. The findings show that the brain can alter how we perceive our bodies all by itself, without input from our senses [Reuters].
Researchers had patients with “vivid phantoms” try to move their wrists in a physically impossible way—a 360 degree spin of the wrist around the long axis of the forearm—and found that 4 of the 7 patients could move their wrists this way. Some patients that were able to move their wrists later reported that their phantom hands were now more difficult to move from side to side because of changes in their phantom arms’ shapes.
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A new discovery about how mantis shrimp process light could give rise to new and more powerful consumer electronics, according to a new study. Mantis shrimp possess the animal kingdom’s most complicated eyes, capable of distinguishing between 100,000 colors — 10 times as many as humans — and seeing circular polarized light, or CPL, which can’t be detected by any other creature [Wired.com]. Circular polarized light is one of two forms of polarized light, or light waves that travel in a specific plane.
The specialized CPL detecting cells in shrimp eye are similar to the optical detectors found in DVD players; each can convert polarized light into other forms so it can be stored or processed. However, shrimp eyes can do this with all colors of circular polarized light across the spectrum, according to the study in Nature Photonics. The detectors in DVD and CD players can only recognize circular polarized light in a few colors. The research team thinks that in the future, optics devices might be beefed up by chemically engineered crystals that could mimic the light polarizing cells of the mantis shrimp eye.
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Snooty wine pairing rules, such as the edict that one must only drink white wine with fish, now have a little data behind them, according to a new study. Researchers found a correlation between the high iron content of red wine and a nasty, fishy aftertaste when the reds are sipped with seafood. In the experiment, tasters ate a bit of scallop, tasted some wine and evaluated the aftertaste on a scale of 1 to 4. The diners found the unpleasant aftertaste was more intense with wines that had a higher iron content, the researchers say [Los Angeles Times]. The researchers were able to block the aftertaste by adding a compound that masks the iron.
The iron content of a wine depends on the composition of the soil in which the grapes were grown, the dust on the berry, contamination during harvesting, transportation, and crushing, and the conditions during fermentation [Telegraph]. The new research, published in Journal of Agricultural and Food Chemistry, suggests that some low-iron red wines are OK to drink with fish. While red wines tend to have more iron than whites, it varies according to the type of grape, country of origin, and vintage.
But the iron is only half the story. The researchers report that they haven’t yet isolated the compound in the scallops that reacts with the wine, but they suspect it’s an unsaturated fatty acid, which could be breaking down rapidly and releasing the decaying fish smell when exposed to iron [ScienceNOW Daily News].
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Image: flickr / yashima
Cracking open a cold can of Coke and taking a bubbling swig will have your taste buds dancing—and now scientists know why. A new study shows that cells in taste buds that respond to sour stimuli also seem to be the ones responsible for tasting the carbonation’s fizz [NPR].The fact that we can taste the carbon dioxide in a fizzing soda has previously puzzled scientists, since the human tongue is usually thought to only sense five flavors—bitter, sweet, salty, sour, and umami (also called savory). However, the new study, published in Science, shows that the sour taste buds have an enzyme that interacts with carbon dioxide, so it’s not the bursting bubbles that you taste, it’s the C02 itself.
The researchers discovered this tricky bit of chemistry by studying mice. They gave the animals sips of club soda or a little buzz of carbon dioxide gas and recorded how the tongue signaled the sensation to the brain. Both soda and the gas produced similar sensations. But when they tested mice bred to have no sour taste buds, the brain never got its sensory alert. Further probing uncovered the enzyme responsible [AP]. The mechanism should be the same in humans, according to the scientists.
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Inside the brain of someone who’s learning to juggle, some interesting changes take place. Researchers used MRI scans to study the brains of people before and after a six-week training course in juggling, and say they saw a 5% increase in white matter – the cabling network of the brain [BBC News].
The study, published in Nature Neuroscience, follows up on previous work that found changes in the more famous gray matter of the brain, which consists of the cell bodies of the neurons where processing and computation take place. The white matter, which consists mostly of the axons that stretch away from the cell bodies, can be thought of as the brain’s wiring, and researchers say this is the first time that changes have been observed in the white matter of a healthy adult.
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Scientists have found another reason why the fizz in a glass of champagne is so important: Besides tickling the tongue and pleasing the eye, the bubbles also release aromatic compounds that they’ve dragged up from the liquid in the glass. A new study found that concentrations of certain chemical compounds are higher in the air just above the glass than in the actual champagne.
Wine expert Jamie Goode comments: “In the past, we thought that the carbon dioxide in the bubbles just gave the wine an acidic bite and a little tingle on the tongue, but this study shows that it is much more than this” [BBC News]. Smelling the chemical compounds enhances the overall flavor of the champagne, researchers say.
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