How a living material of cheese fungi sandwiched between plastic sheets works.
The crusty rind of cheeses like Camembert provide more than texture: they are miniature fortress walls, made of fungus, that protect the cheese’s creamy insides from bacterial invasions. Now, taking inspiration from this delicious snack, chemical engineers at ETH Zurich in Switzerland have shown that such a fungus can be enclosed in porous plastic and will digest spills, with implications for creating antibacterial surfaces from living material.
The team sandwiched a layer of Penicillium roqueforti—from, you guessed it, Roquefort cheese—between a plastic base and a top sheet of plastic with nanoscale pores that allowed gas and liquids to move through, but did not allow the fungus to spread. Then, they mimicked a kitchen spill by pouring sugary broth on the surface and watched as, over the course of two weeks, the captive fungus gradually consumed the entire spill, leaving the surface clean. As shown in the figure above, the fungi can go dormant when there is no food around, so if one had a countertop of such a material, you wouldn’t need to keep spilling sugar on it to keep the fungi happy. (more…)
What’s the News: Scientists have developed a chip that can instantaneously identify fluids applied to it, just from their unique surface tension. In a handheld device, it could help toxic site remediators figure out what that ominous clear liquid is. And there’s a bonus for the kids-in-the-treehouse user demographic: different secret messages can appear on the chip depending on what fluid is applied.
Dealing with damaged soft tissue is often more complex than dealing with damaged bone and skin. The shape of someone’s face is dependent on the fat, muscle, and other tissue below the surface, and doctors trying to restore someone’s facial structure must contend with scar tissue, swelling, and loss of movement.
Most archaeologists dig up the past, examining artifacts for clues—but experimental archaeologists build the past from the ground up, testing out what they can make and do using the same tools and techniques ancient peoples did. Brandon Keim at Wired Science has compiled a fascinating collection of these studies, following scientists as they sail the South Pacific on rafts of balsa wood, hunt deer with flint-tipped spears, and build smoky fires to keep warm through the Scandinavian winter (above).
The weave of the new translucent fabric traps sound, while letting light—and in this photo from the Swiss lab, a view of neighboring houses—through.
What’s the News: Noisy rooms are no fun, but neither are those smothered in heavy sound-canceling drapes. The solution? A translucent curtain that quenches sound by behaving like foam, developed by Swiss materials scientists and a textile designer.
What’s the News: Researchers have developed the fastest yet self-healing polymer: The new class of materials dubbed “metallo-supramolecular polymers” heal after only one minute under UV light even when they’re repeatedly cut. This could eventually lead to self-repairing floor varnishes, automotive paints, and other applications. University of Illinois at Urbana researchers Nancy Sottos and Jeffrey Moore say these these healable polymers “offer an alternative to the damage-and-discard cycle” that is rampant in our consumer society, and could pave the way for products “that have much greater lifespans than currently available materials.” (You can see the process below in a press video from Case-Western Reserve University.)
Materials violence: NASA will use a million pounds of force to crush a 20-foot-tall aluminum-lithium rocket fuel tank outfitted with sensors (all in the name of science, of course). The idea is to test out how modern composite materials buckle under incredible pressure, in the hope of finding out where the weaknesses might be.
Real-life forensic science is rarely as easy or glamorous as its TV counterpart. Actual blood spatter experts, for example, don’t operate with quite the ease of the title character in “Dexter.” But a new study proposes a way to use simple trigonometry to calculate not only the point of origin for blood but also the height above the ground, which previously couldn’t be determined.
Half of adult males may be carrying the human papillomavirus (HPV), according to a study in The Lancet. It often lingers quietly but is transmitted sexually and is the cause of most cervical cancers in women.
“Strictly speaking, there should be no blue whales.” So begins DISCOVER blogger Carl Zimmer as he explores the curious question of why blue whales, with so many more cells than human beings and so many chances for those cells to go wrong, are not killed by cancer at an astounding rate.
Forget about fancy metamaterials that can make microscopic objects invisible–researchers at two different universities have independently shown that larger objects can be rendered invisible using a mineral that’s both naturally occurring and common: calcite.
This latest step in physicists’ ongoingquest to create an invisibility cloak come from an MIT lab, with a paper published in Physical Review Letters, and a University of Birmingham lab, whose paper just came out in Nature Communications. Both teams explained that they used calcite to make objects that are large enough to be seen with the naked eye invisible.
“By using natural crystals for the first time, rather than artificial metamaterials, we have been able to scale up the size of the cloak and can hide larger objects, thousands of times bigger than the wavelength of the light,” said Shuang Zhang, the University of Birmingham physicist who led the research…. “This is a huge step forward as, for the first time, the cloaking area is rendered at a size that is big enough for the observer to ‘see’ the invisible object with the naked eye.” [BBC]
The researchers constructed their cloaks from two glued-together calcite crystals, which have a convenient optical property called birefringence–that means they can bend a ray of light in two different directions. Then they placed the objects to be concealed in a notch beneath the crystals.
This picture may look like an exuberant patchwork quilt, or a stretch of really interesting farmland as seen from an airplane. In fact, what you’re looking at is sheet of graphene–a one-atom-thick layer of carbon, measuring about 100,000 atoms across.
The image, produced by an electron microscope, reveals that the honeycomb-like lattice of carbon atoms that forms a sheet of graphene is full of irregularities. Each sheet is composed of patches of atoms, and each patch has a slightly different rotation than that of its neighbors. By firing electrons at a sheet and using different colors to identify the angles at which the electrons bounced back, researchers made this rainbow image of a graphene sheet with the patch boundaries clearly shown.
Lead researcher David Muller says this is an easy and efficient way to understand a graphene sheet’s properties.
“You don’t want to look at the whole quilt by counting each thread. You want to stand back and see what it looks like on the bed. And so we developed a method that filters out the crystal information in a way that you don’t have to count every atom,” said David Muller, professor of applied and engineering physics and co-director of the Kavli Institute at Cornell for Nanoscale Science. [press release]
The research, which was published in Nature, will be useful as nanotechnologists continue to investigate graphene’s exciting electrical properties. Researchers had previously thought that larger patches would improve the electrical conductivity of graphene, but Muller’s experiments suggest that theory is wrong. Rather, it’s impurities in graphene sheets that interfere with their conductivity, he argues.
Now and then we stop to marvel at the feats of carbon nanotube researchers, who use these infinitesimal tubes to build materials of adamantine strength and impressive electrical conductivity. But what if you could marry the robustness of nanotubes to the stretchiness of viscous liquids? You’d be Xu Ming and his fellow Japan-based scientists, who have creating a super rubber that—unlike normal rubber—does not crack and fall apart at extreme temperatures.
Xu’s team outlines its creation in a study for this week’s edition of the journal Science.
Made entirely of carbon, it can flow and stretch slowly like thick honey and spring back to its original form, said [Xu].”It looks like a metal sponge that is porous, it is made from trillions of entangled carbon nanotubes,” she said in a telephone interview. “When you stretch and release it, it can come back slowly (to its original shape).” [ABC News]
The material’s litany of talents—especially its ability to keep its shape up to temperatures of 1000 degrees C (1832 Fahrenheit) and down to -196 C (-321 F)—inspires visions of using it in all kinds of extreme conditions.
That huge range of temperatures means the new material could be used in everything from spacecraft to car shock absorbers, said Roderic Lakes, a scientist at the University of Wisconsin who studies viscoelastic materials. Spacecraft equipped with this material could withstand the intense cold of [Saturn]‘s largest moon, Titan, said Gogotsi, or the heat of the sun in space, said Lakes. [Discovery News]
First came the formulation of an invisibility cloak that could bend light around an object. Then, this spring, German scientists took that idea and made it three-dimensional. Is the invisibility cloak now ready to go 4D? For a study in the Journal of Optics, British researcher Martin McCall’s team adds the dimension of time to the invisibility cloak idea, creating a theoretical “space-time cloak.”
The key feature of the proposed space–time cloak is that its refractive index — the optical property that governs the speed of light within a material — is continually changed, pulling light rays apart in time. When the leading edge of a light wave hits the cloak, the material is manipulated to speed up the light, but when the trailing edge hits, the light is slowed down and delayed. “Between these two parts of the light, there will be a temporal void — a space in which there will be no illuminating light for a brief period of time,” explains McCall. [Nature]
Taking advantage of these differences, he says, it is theoretically possible to imagine a cloak that allows you—at least from my point of view—to transport instantaneously across space.
A new approach to electrophoresis is giving researchers more control over how they play with small particles.
Electrophoresis is the movement of particles in solution under a current–a phenomenon that can be exploited for use in everything from ePaper to DNA separating gels. Instead of using a normal fluid to conduct current, researchers led by Oleg Lavrentovich tried using liquid crystals as their conductive fluid.
Liquid crystals, like those seen in the first three pictures above (which might look similar to the patterns you’ve seen when you push on the screen of some of your electronics), act like a fluid. But instead of being a disorganized jumble of molecules, the individual rod-shaped particles line up parallel to each other. When they take on different orientations, they refract different colors of light, a phenomenon called birefringence.
Flexible materials technology may just bring the next wave of trendy to the markets, in the form of glowing tattoos and T- shirts. Or the hot new tech could be used for its intended purpose: monitoring medical conditions.
This flexible light-emitting diode (LED) array uses many already existing materials and techniques to create a nano-sized, flexible patch of light. A team lead by John Rogers developed the array as a medical device; it could be implanted to serve as a readout for monitoring internal body conditions, like blood oxygenation or glucose levels, or it could turn on light-activated drugs.
“The applications we’re interested in mostly include interfaces with the human body,” says John Rogers…. For some biological applications, he adds, a conventional LED’s brightness, reliable operation and suitability for waterproof implementation make it a more attractive option than an organic LED. [Scientific American].
Each individual LED is a square that measures 2.5 micrometers thick (smaller than the diameter of your cells’ nucleus) and 100 micrometers on each side (the thickness of a coat of paint). Many of these LEDs can be printed together to form an array of light points connected by swirls of connective wire that give it additional flexibility. The substrate is flexible enough that it can be stretched and flexed up to 75 percent without losing function. The researchers described the technology in the journal Nature Materials.
The wonder material snagged the 2010 Nobel Prize in Physics today, bringing the award to Russian scientists Andre Geim and Konstantin Novoselov who work at the University of Manchester in the U.K.
Novoselov and Geim didn’t discover graphene, which is made of sheets of carbon just one atom thick. Physicists had known about it for years, but these two showed the way to produce it quickly and easily.
Novoselov was a postdoctoral fellow working in Geim’s lab in 2004 when the researchers discovered that they could make atomically thin slabs of carbon by repeatedly cleaving graphite—essentially pencil lead—with adhesive tape. Their 2004 Science paper describing the material and its the electrical properties has already been cited more than 3,000 times, according to Thomson Web of Science. [Scientific American]
80beats is DISCOVER's news aggregator, weaving together the choicest tidbits from the best articles on the day's most compelling topics.
80beats is written by Veronique Greenwood and Valerie Ross. This team darts through each day's science news faster than the ruby-throated hummingbird that beats its wings 80 times per second. Send ideas, tips, suggestions, and complaints to [azeeberg at discovermagazine dot com].
The weave of the new translucent fabric traps sound, while letting light—and in this photo from the Swiss lab, a view of neighboring houses—through.
Forget about fancy 
Now and then we stop to marvel at the feats of carbon 
First came the formulation of an 
Graphene.
