How do you make a human ear that looks and functions like a real one? Researchers at Cornell published the first successful process in PLoS ONE Wednesday.
Step 1: Take a laser scan of a real human ear.
Step 2: Use digitization to print an ear-shaped collagen mold using a 3-D printer.
Step 3: Inject mold with gel of living cells.
DEET is the mother of all mosquito repellants. Its strong stench keeps bugs at bay by affronting their olfactory systems with an intensely offensive odor. But scientists are now running into a problem with DEET’s effectiveness: after three hours the stuff no longer deters buzzing biters.
N,N-Diethyl-3-methylbenzamide, a.k.a. DEET, first emerged as a pesticide for crops, but the U.S. military then developed the chemical for use against biting insects in jungle environments during World War II. Available as a spray or a lotion, DEET is still used today to repel flies, ticks and mosquitoes, and to protect against the diseases these bugs can transmit.
But now, researchers in London have shown that three hours after Aedes aegypti mosquitoes were exposed to DEET, they seemed to become immune to the smell and were no longer repulsed by it. This species, also known as the yellow fever mosquito, is notorious for spreading tropical diseases.
A virus related to SARS has claimed its sixth victim, officials announced yesterday. A British man has died of the coronavirus, called HCoV-EMC, which was first identified last year. There have been a total of 12 cases of the coronavirus in the UK, Saudi Arabia and Jordan.
Now in a new study researchers have actually quantified the infection rate of the new virus. Results show that at a cellular level EMC is as efficient at infecting human cells as the common cold. Scientists isolated cells from the lining of three healthy people’s airways and cultured them in the lab, then introduced EMC, SARS, and a common cold virus to different groups of cells.
They found that EMC did indeed replicate in the airway cells (this tissue is especially vulnerable, which explains why infected individuals suffer respiratory problems). No detectable inflammation was produced, meaning that cells’ inbuilt immune defenses didn’t even see the virus, signalling that EMC is very effective at evading immune system defenses. However, its efficiency at causing disease is yet to be determined. Many coronaviruses are similarly good at infecting human cells—ie, getting inside them and replicating—but they cause only mild disease symptoms.
In people with hereditary retinal diseases like retinitis pigmentosa, the eyes’ photoreceptors, or light sensors, degenerate slowly over time, eventually leading to blindness. While these people are unable to see, the rest of their visual pathway remains intact and functional. Researchers in Germany now have a way to work around this roadblock by introducing an implant to take the place of the broken photoreceptors and restore some level of communication directly with a patient’s visual pathway.
The researchers implanted a tiny electronic device under the retina of patients to take the place of their non-functioning photoreceptors. The implant is only about a third of an inch squared—the size of a Chiclet—and converts light into electrical signals. It is powered wirelessly via a battery pack attached behind the patient’s ear.
It’s pretty standard for scientists to look at human skeletons to reconstruct past human health. But a new approach looks not at our ancestors themselves but the hardened gunk on their teeth to re-create the timeline of human dietary changes.
Scientists performed that analysis by looking at an array of ancient teeth. They found that shifts in the human diet over the millennia have led to big drop-offs in the diversity of good bacteria in our mouths—and the result is a severely weakened oral ecosystem and an increased risk of various diseases.
Saliva contains bacteria and minerals which accumulate on our teeth as plaque. Since skeletons can’t brush their teeth, this film eventually crystallizes on tooth enamel to become almost bone-like, preserving the bacterial DNA inside it. The DNA of bacteria in crystallized plaque provides a snapshot of a person’s diet, health and oral pathogens.
Paleontologists in California announced this week that fossils excavated in the early 2000s represent four new species of ancient whales. The toothed baleen whales apparently stuck around longer than scientists once thought, and they may hold clues about how and when whales evolved from toothy giants to the baleen-equipped beasts we see today.
Supernovae, the spectacular death rattles of the largest stars, are the astronomical gifts that keep giving.
The stellar explosions can add a temporary new jewel to the night (and sometimes day) sky, and they leave behind spectacular and intricate formations known as remnants. A certain class of supernovae helped astronomers realize that the universe’s expansion is speeding up, leading to the “discovery” of dark energy pervading our cosmos. And now, it seems, supernovae might ultimately be to blame for one of astronomy’s longest running mysteries: the origins of cosmic rays.
Scientists have known about these ridiculously energetic and high-velocity particles for nearly a hundred years. In daily life, cosmic rays may be familiar as the source of extra radiation airline passengers are exposed to. However scientists have been uncertain about where cosmic rays come from. The extreme conditions of temperature and speed that accompany supernovae and their remains made them a natural starting point for guesses. Now two separate Science papers finally provide evidence that cosmic rays do indeed come from supernovae remnants.
“Must be something in the water” isn’t just a line from the opening minutes of a horror movie.
New evidence confirms fears that animals’ behavior can be altered by medication inadvertently introduced into their habitats via our sewage systems.
In a study published today Swedish researchers report that fish given Oxazepam, an anxiety-moderating drug for humans, became less social and more aggressive. Researchers administered the drug to wild perch in the lab in amounts equivalent to levels found in local rivers and streams.
The dosed fish showed a number of behavioral changes, notably in their willingness to leave familiar and “safe” surroundings in favor of exposed, potentially dangerous areas. The fish treated with the drug also distanced themselves from other perch. These antisocial fish ate faster than normal, which, in the wild, could disrupt the established food chain.
It’s not as exciting as El Dorado’s source of eternal youth, but nitric oxide-producing bacteria are extending the lifespan of the humble roundworm Caenorhabditis elegans.
The worm lacks the enzyme needed to produce nitric oxide. In animals which are capable of manufacturing nitric oxide, it has been shown to increase blood flow, promote efficient nerve signal transmission and regulate the immune system, all factors that may contribute to a longer lifespan.
To see if nitric oxide alone could extend lifetime, researchers fed a group of C. elegans a soil-dwelling bacterium called Bacillus subtilis, which produces the gas. The worms, with colonies of B. subtilis established in their guts, had a lifespan of about two weeks—nearly 15 percent longer than a control group fed bacteria which didn’t produce nitric oxide.