‘Lasers Rewired’: Scientists Find a New Way to Make Nanowire Lasers

This sequence of nanolaser images shows a dark-field image of a cesium lead bromide

nanowire (red) that emits increasingly bright laser light (green) when excited by an

external laser. (Credit: Sam Eaton/UC Berkeley)

(February 12, 2016)  Scientists at the U.S. Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) and UC Berkeley have found a simple new way to produce nanoscale wires that can serve as tiny, tunable lasers.

The nanowires, with diameters as small as 200 nanometers (billionths of a meter) and a blend of materials that has also proven effective in next-generation solar cell designs, were shown to produce very bright, stable laser light. Researchers say the excellent performance of these tiny lasers is promising for the field of optoelectronics, which is focused on combining electronics and light to transmit data, among other applications.

Light can carry far more data, far more rapidly than standard electronics—a single fiber in a fiber-optic cable, measuring less than a hair’s width in diameter, can carry tens of thousands of telephone conversations at once, for example. And miniaturizing lasers to the nanoscale could further revolutionize computing by bringing light-speed data transmission to desktop and ultimately handheld computing devices.

This nanowire, composed of cesium, lead and bromide (CsPbBr3),

emits bright laser light after hit by a pulse from another laser source.

The nanowire laser proved to be very stable, emitting laser light

for over an hour. It also was demonstrated to be broadly tunable across

green and blue wavelengths. The white line is a scale bar that measures 2 microns,

or millionths of an inch. (Credit: Sam Eaton/UC Berkeley)

“What’s amazing is the simplicity of the chemistry here,” said Peidong Yang, a chemist in Berkeley Lab’s Materials Sciences Division who led the research, published Feb. 9 in Proceedings of the National Academy of Sciences. More standard techniques that produce nanowires can require expensive equipment and exotic conditions, such as high temperatures, and can suffer from other shortcomings.

A nanowire construction zone: This scanning electron microscope image shows a collection

of cesium lead bromide (CsPgbBr3) nanowires and nanoplates grown from a chemical-dipping

process. To produce these structures, researchers dipped a thin lead-containing film into

a methanol solution containing cesium, bromine and chlorine heated to about 122 degrees.

The white scale bar at the lower right represents 10 microns. The image at the bottom left

shows the well-formed rectangular end of a nanowire—the white scale bar associated with it

represents 500 nanometers. (Credit: Sam Eaton/UC Berkeley)

The research team developed a simple chemical-dipping solution process to produce a self-assembled blend of nanoscale crystals, plates and wires composed of cesium, lead and bromine (with the chemical formula: CsPbBr3). The same chemical blend, with a molecular architecture composed of cube-like crystal structures, has also proven effective in an emerging wave of new designs for high-efficiency solar cells.

“Most of the earlier work with these types of materials is focused on these solar energy applications,” said Yang, who also holds appointments with UC Berkeley and the Kavli Energy NanoScience Institute at Berkeley Lab and UC Berkeley. “There has been so much progress with these materials in just the past several years—I have a feeling these materials will open a new research frontier for optoelectronics as well,” he said, and in the broader field of photonics, which is focused on using light for a range of applications.

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Scientists learn how young brains form lifelong memories by studying worms’ food choices

(February 11, 2016) Members of neuroscientist Cori Bargmann’s lab spend quite a bit of their time watching worms move around. These tiny creatures, Caenorhabditis elegans, feed on soil bacteria, and their very lives depend on their ability to distinguish toxic microbes from nutritious ones. In a recent study, Bargmann and her colleagues have shown that worms in their first larval stage can learn what harmful bacterial strains smell like, and form aversions to those smells that last into adulthood.

Many animals are capable of making vital, lifelong memories during a critical period soon after birth. The phenomenon, known as imprinting, allows newly hatched geese to bond with their moms, and makes it possible for salmon to return to their native stream after spawning. And while the learning processes of humans may be more complex and subtle, scientists have long known that our brain’s ability to store a memory and maintain it long-term depends on when and how that memory was acquired.

“In the case of worms, we were fascinated to discover that their small and simple nervous system is capable of not only remembering things, but of forming long-term memories,” says Bargmann, who is Torsten N. Wiesel Professor and head of the Lulu and Anthony Wang Laboratory of Neural Circuits and Behavior, as well as co-director of the new Kavli Neural Systems Institute at Rockefeller. “It invites the question of whether learning processes that happen during different life stages are biologically different.”

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Gravitational Waves Detected 100 Years After Einstein’s Prediction

The plots show signals of gravitational waves detected by the twin LIGO observatories.

The signals came from two merging black holes 1.3 billion light-years away.

The top two plots show data received at each detector, along with waveforms predicted

by general relativity. The X-axis plots time, the Y-axis strain—the fractional amount by

which distances are distorted. The LIGO data match the predictions very closely.

The final plot compares data from both facilities, confirming the detection. Credit: LIGO

(February 11, 2016)  LIGO opens new window on the universe with observation of gravitational waves from colliding black holes

For the first time, scientists have observed ripples in the fabric of spacetime called gravitational waves, arriving at the earth from a cataclysmic event in the distant universe. This confirms a major prediction of Albert Einstein's 1915 general theory of relativity and opens an unprecedented new window onto the cosmos.

Gravitational waves carry information about their dramatic origins and about the nature of gravity that cannot otherwise be obtained. Physicists have concluded that the detected gravitational waves were produced during the final fraction of a second of the merger of two black holes to produce a single, more massive spinning black hole. This collision of two black holes had been predicted but never observed.

The gravitational waves were detected on September 14, 2015 at 5:51 a.m. Eastern Daylight Time (09:51 UTC) by both of the twin Laser Interferometer Gravitational-wave Observatory (LIGO) detectors, located in Livingston, Louisiana, and Hanford, Washington, USA. The LIGO Observatories are funded by the National Science Foundation (NSF), and were conceived, built, and are operated by Caltech and MIT. The discovery, accepted for publication in the journal Physical Review Letters, was made by the LIGO Scientific Collaboration (which includes the GEO Collaboration and the Australian Consortium for Interferometric Gravitational Astronomy) and the Virgo Collaboration using data from the two LIGO detectors.

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New NTU smart chip makes low-powered, wireless neural implants a possibility

Versatile chip also offers multiple applications in various electronic devices

(February 11, 2016)  Scientists at Nanyang Technological University, Singapore (NTU Singapore) have developed a small smart chip that can be paired with neural implants for efficient wireless transmission of brain signals.

Neural implants when embedded in the brain can alleviate the debilitating symptoms of Parkinson’s disease or give paraplegic people the ability to move their prosthetic limbs.

However, they need to be connected by wires to an external device outside the body. For a prosthetic patient, the neural implant is connected to a computer that decodes the brain signals so the artificial limb can move.

These external wires are not only cumbersome but the permanent openings which allow the wires into the brain increases the risk of infections.

The new chip by NTU scientists can allow the transmission of brain data wirelessly and with high accuracy.

Assistant Professor Arindam Basu from NTU’s School of Electrical and Electronic Engineering said the research team have tested the chip on data recorded from animal models, which showed that it could decode the brain’s signal to the hand and fingers with 95 per cent accuracy.

“What we have developed is a very versatile smart chip that can process data, analyse patterns and spot the difference,” explained Prof Basu.

“It is about a hundred times more efficient than current processing chips on the market. It will lead to more compact medical wearable devices, such as portable ECG monitoring devices and neural implants, since we no longer need large batteries to power them.”

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“Electronic nose” from a TSU scientist will help to diagnose diseases

(February 10, 2016)  Timur Muksunov, research engineer at the SPhTI Laboratory for Security Methods, Systems and Technologies has created a gas analyzer - "electronic nose" that is able to assess the quality of the food, cosmetic, and medical products, to diagnose diseases by human exhaled gases, and even detect explosives and drugs.

However, according to the scientist, it is impossible to make a sensor that reacts to only one gas – the system is needed to achieve sensitivity and selectivity. This allows, when using certain processing techniques, accurately recognizing the gas mixture in the air. Experiments confirm this.

One of them was determining the freshness of fruits and vegetables. Fruits and vegetables emit hydrogen sulphide, ammonia, and other gases. The closer the date of writing off the products, the more of these gases are in the air.

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Drones Learn To Search Forest Trails for Lost People

Using a new software drones detect forest paths and can follow these

autonomously.  (Image: UZH; USI; SUPSI)

(February 10, 2016)  Researchers at the University of Zurich, the Università della Svizzera italiana, and the University of Applied Sciences and Arts of Southern Switzerland have developed software enabling drones to autonomously detect and follow forest paths. With the new drones, missing persons can be found and rescued quickly in forests and mountain areas.

Every year, thousands of people lose their way in forests and mountain areas. In Switzerland alone, emergency centers respond to around 1,000 calls annually from injured and lost hikers. But drones can effectively complement the work of rescue services teams. Because they are inexpensive and can be rapidly deployed in large numbers, they substantially reduce the response time and the risk of injury to missing persons and rescue teams alike.

A group of researchers from the Dalle Molle Institute for Artificial Intelligence and the University of Zurich has developed artificial intelligence software to teach a small quadrocopter to autonomously recognize and follow forest trails. A premiere in the fields of artificial intelligence and robotics, this success means drones could soon be used in parallel with rescue teams to accelerate the search for people lost in the wild.

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Radiation causes blindness in wild animals in Chernobyl

Myodes glareolus / Bank vole

(February 10, 2016) Female voles are more susceptible to cataracts than males

This year marks 30 years since the Chernobyl nuclear accident. Vast amounts of radioactive particles spread over large areas in Europe. These particles, mostly Cesium-137, cause a low but long-term exposure to ionizing radiation in animals and plants.

This chronic exposure has been shown to decrease the abundances of many animal species both after the Chernobyl and later Fukushima nuclear accidents. Damage caused by acute exposure to high radiation doses have been demonstrated in numerous laboratory studies, but effects of chronic exposure to low radiation in the wild remain largely unknown.

New research now suggests that chronic exposure to low radiation can cause damage to the eyes of wild animals. This is shown in an international study led by researchers Philipp Lehmann and Tapio Mappes from the University of Jyväskylä, Finland, which recently was published in the journal Scientific Reports.

In the study higher frequencies of cataracts were found in the lenses of bank voles which had lived in areas where background radiation levels were elevated compared to areas with natural radiation levels. Cataract frequency increased with age in the voles, similarly as in humans generally. In addition, the effects of aging intensified as a result of elevated radiation.

Interestingly the effect of radiation was significant only in female voles. Also in humans there are indications for high radiosensitivity of lenses. Persons with occupational exposure to radiation, such as radiology nurses, nuclear power plant workers and airline pilots have increased risk of cataract, but potential gender differences in radiosensitivity should be further studied.

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Creating a color printer that uses a colorless, non-toxic ink inspired by nature

This image of a squirrel was printed in color by controlling the

thickness of a colorless ink deposited on a thin film.

Credit: American Chemical Society

(February 10, 2016)  From dot-matrix to 3-D, printing technology has come a long way in 40 years. But all of these technologies have created hues by using dye inks, which can be taxing on the environment. Now a team reports in ACS Nano the development of a colorless, non-toxic ink for use in inkjet printers. Instead of relying on dyes, the team exploits the nanostructure of this ink to create color on a page with inkjet printing.

Current technologies blend dyes — think CMYK or RGB — to print in color. But these substances can harm the environment. Some dyes are toxic to marine life or can react with disinfectants like chlorine and form harmful byproducts. An alternative to dyes involves changing the nanostructure of materials so that they reflect light in particular ways. An example of this kind of coloring by light interference is found in nature: Squids can modify the nanostructure of their skin to mirror back their surrounding environment, creating a natural camouflage. Previous research has investigated printing color by light interference, but these attempts have required high-temperature fixing or specialized printing surfaces.  Aleksandr V. Yakovlev, Alexandr V. Vinogradov and colleagues at ITMO University wanted to develop a nanostructure color printing technology that is “greener” and can be printed on a wide variety of surfaces.

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The most accurate optical single-ion clock worldwide

Schematic representation: Measuring the influence of thermal ambient radiation

on the frequency of the trapped ion: the "clock laser" (blue beam) excites the trapped

ion (yellow) with a special pulse sequence. The resonance frequency of the ion is

influenced by infrared radiation (here by an infrared laser, red beam).

This can be measured by means of the clock laser. (Fig.: PTB)

(February 10, 2016)  Scientists from the Physikalisch-Technische Bundesanstalt (PTB) reduce the measurement uncertainty of their ytterbium clock down to 3 ∙ 10–18

Atomic clock experts from the Physikalisch-Technische Bundesanstalt (PTB) are the first research group in the world to have built an optical single-ion clock which attains an accuracy which had only been predicted theoretically so far. As early as 1981, Hans Dehmelt, who was to be awarded a Nobel prize later, had already developed the basic notions of how to use an ion kept in a high-frequency trap to build a clock which could attain the – then unbelievably low – relative measurement uncertainty in the range of 10–18. Ever since, an increasing number of research groups worldwide have been trying to achieve this with optical atomic clocks (either based on single trapped ions or on many neutral atoms). The PTB scientists are the first to have reached the finishing line using a single-ion clock. Their optical ytterbium clock achieved a relative systematic measurement uncertainty of 3 ∙ 10–18. The results have been published in the current issue of the scientific journal "Physical Review Letters".

Radio-frequency trap of PTB's optical ytterbium single-ion clock. (Photo: PTB)

The definition and realization of the SI unit of time, the second, is currently based on cesium atomic clocks. Their "pendulum" consists of atoms which are excited into resonance by microwave radiation (1010 Hz). It is regarded as certain that a future redefinition of the SI second will be based on an optical atomic clock. These have a considerably higher excitation frequency (1014 to 1015 Hz), which makes them much more stable and more accurate than cesium clocks.

The accuracy now achieved with the ytterbium clock is approximately a hundred times better than that of the best cesium clocks. To develop their clock, the researchers from PTB exploited particular physical properties of Yb+. This ion has two reference transitions which can be used for an optical clock. One of these transitions is based on the excitation into the so-called "F state" which, due to its extremely long natural lifetime (approx. 6 years), provides exceptionally narrow resonance. In addition, due to the particular electronic structure of the F state, the shifts of the resonance frequency caused by electric and magnetic fields are exceptionally small. The other reference transition (into the D3/2 state) exhibits higher frequency shifts and is therefore used as a sensitive "sensor" to optimize and control the operating conditions. Another advantage is that the wavelengths of the lasers required to prepare and excite Yb+ are in a range in which reliable and affordable semiconductor lasers can be used.

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Researchers engineer an electronics first, opening door to flexible electronics

UAlberta electrical engineering PhD student Gem Shoute (second from right) is the

lead author on a research paper demonstrating a powerful new flexible transistor.

The team: electrical engineering professor Doug Barlage, Triranta Muneshwar, Shoute

and materials engineering professor Ken Cadien, published its work in Nature Communications.

(February 9, 2016)  An engineering research team at the University of Alberta has invented a new transistor that could revolutionize thin-film electronic devices.

Their findings, published in the prestigious science journal Nature Communications (read the article here), could open the door to the development of flexible electronic devices with applications as wide-ranging as display technology to medical imaging and renewable energy production.

The team was exploring new uses for thin film transistors (TFT), which are most commonly found in low-power, low-frequency devices like the display screen you’re reading from now. Efforts by researchers and the consumer electronics industry to improve the performance of the transistors have been slowed by the challenges of developing new materials or slowly improving existing ones for use in traditional thin film transistor architecture, known technically as the metal oxide semiconductor field effect transistor (MOSFET).

But the U of A electrical engineering team did a run-around on the problem. Instead of developing new materials, the researchers improved performance by designing a new transistor architecture that takes advantage of a bipolar action. In other words, instead of using one type of charge carrier, as most thin film transistors do, it uses electrons and the absence of electrons (referred to as “holes”) to contribute to electrical output. Their first breakthrough was forming an ‘inversion’ hole layer in a ‘wide-bandgap’ semiconductor, which has been a great challenge in the solid-state electronics field.

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Carbon fibre from wood is used to build car

This model car's carbon fibre roof and battery electrodes are made with wood

(February 9, 2016)  Remember wood paneled station wagons? Well, wood is back, but this time it's not for aesthetics — it's for reducing vehicle weight with renewable materials. Swedish researchers have just produced the world's first model car with a roof and battery made from wood-based carbon fibre.

Although it's built on the scale of a toy, the prototype vehicle represents a giant step towards realizing a vision of new lightweight materials from the forest, one of the benefits of a so-called bioeconomy.

The demo is a joint project of KTH Royal Institute of Technology, the Swedish researcher institute Innventia and Swerea, a research group for industrial renewal and sustainable development.

The key ingredient in the carbon fibre composite is lignin, a constituent of the cell walls of nearly all plants that grow on dry land. Lignin is the second most abundant natural polymer in the world, surpassed only by cellulose.

Göran Lindbergh, Professor of Chemical Engineering at KTH, says that the use of wood lignin as an electrode material came from previous research he did with Innventia. Lignin batteries can be produced from renewable raw materials, in this case the byproduct from paper pulp production.

"The lightness of the material is especially important for electric cars because then batteries last longer," Lindbergh says. "Lignin-based carbon fiber is cheaper than ordinary carbon fibre. Otherwise batteries made with lignin are indistinguishable from ordinary batteries."

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Body heat triggers shape change in new type of polymer

A time-lapse photo of a new shape-memory polymer reverting to its original shape

after being exposed to body temperature. (University of Rochester photo / J. Adam Fenster)

(February 9, 2016)  Material Can Lift 1000 Times Its Mass

Polymers that visibly change shape when exposed to temperature changes are nothing new. But a research team led by Chemical Engineering Professor Mitch Anthamatten at the University of Rochester created a material that undergoes a shape change that can be triggered by body heat alone, opening the door for new medical and other applications.

The material developed by Anthamatten and graduate student Yuan Meng is a type of shape-memory polymer, which can be programmed to retain a temporary shape until it is triggered—typically by heat—to return to its original shape.

  

The findings are being published this week in the Journal of Polymer Science Part B: Polymer Physics.

“Tuning the trigger temperature is only one part of the story,” said Anthamatten. “We also engineered these materials to store large amount of elastic energy, enabling them to perform more mechanical work during their shape recovery”

The key to developing the new polymer was figuring out how to control crystallization that occurs when the material is cooled or stretched. As the material is deformed, polymer chains are locally stretched, and small segments of the polymer align in the same direction in small areas—or domains—called crystallites, which fix the material into a temporarily deformed shape. As the number of crystallites grows, the polymer shape becomes more and more stable, making it increasingly difficult for the material to revert back to its initial—or “permanent”—shape.

“Our shape-memory polymer is like a rubber band that can lock itself into a new shape when stretched,” said

Anthamatten. “But a simple touch causes it to recoil back to its original shape.”

The ability to tune the trigger temperature was achieved by including molecular linkers to connect the individual polymer strands. Anthamatten’s group discovered that linkers inhibit—but don’t stop—crystallization when the material is stretched. By altering the number and types of linkers used, as well as how they’re distributed throughout the polymer network, the Rochester researchers were able to adjust the material’s stability and precisely set the melting point at which the shape change is triggered.

Heating the new polymer to temperatures near 35 °C, just below the body temperature causes the crystallites to break apart and the material to revert to its permanent shape.

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Slime can see

infographic credit: elife

(February 9, 2016)  After more than 300 years of looking, scientists led by Queen Mary University of London, have figured out how bacteria “see” their world. And they do it in a remarkably similar way to us.

A team of British and German researchers reveal in the journal eLife how bacterial cells act as the equivalent of a microscopic eyeball or the world’s oldest and smallest camera eye.

“The idea that bacteria can see their world in basically the same way that we do is pretty exciting,” says lead researcher Conrad Mullineaux, Professor of Microbiology from QMUL’s School of Biological and Chemical Sciences

Cyanobacteria are found in huge numbers in water bodies or can form a slippery green film on rocks and pebbles. The species used in the study, Synechocystis, is found naturally in freshwater lakes and rivers. Cyanobacteria evolved around 2.7 billion years ago and the fact that they are able to produce oxygen and fix carbon dioxide using energy from the sun – photosynthesis - is thought to have caused mass extinctions and the oldest known ice age.

As photosynthesis is crucial to the survival of these bacteria, scientists have sought to understand how they sense light.

Previous studies have shown that they contain photosensors and that they are able to perceive the position of a light source and move towards it, a phenomenon called phototaxis.

The current study reveals that they are able to do this because the cell body acts like a lens. As light hits the spherical surface, it refracts into a point on the other side of the cell. This triggers movement by the cell away from the focused spot.

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Iowa State engineers develop hybrid technology to create biorenewable nylon

Zengyi Shao and Jean-Philippe Tessonnier, left to right, are combining

their expertise in biocatalysis and chemical catalysis to produce a new type

of biobased nylon. Photo by Christopher Gannon.

(February 9, 2016)  Engineers at Iowa State University have found a way to combine a genetically engineered strain of yeast and an electrocatalyst to efficiently convert sugar into a new type of nylon.

Previous attempts to combine biocatalysis and chemical catalysis to produce biorenewable chemicals have resulted in low conversion rates. That’s usually because the biological processes leave residual impurities that harm the effectiveness of chemical catalysts.

The engineers’ successful hybrid conversion process is described online and as the cover paper of the Feb. 12 issue of the journal Angewandte Chemie International Edition.

“The ideal biorefinery pipelines, from biomass to the final products, are currently disrupted by a gap between biological conversion and chemical diversification. We herein report a strategy to bridge this gap with a hybrid fermentation and electrocatalytic process,” wrote lead authors Zengyi Shao and Jean-Philippe Tessonnier, Iowa State assistant professors of chemical and biological engineering who are also affiliated with the National Science Foundation Engineering Research Center for Biorenewable Chemicals (CBiRC) based at Iowa State.

The process described by the engineers “opens the door to the production of a broad range of compounds not accessible from the petrochemical industry,” Shao said.

Moving forward, the engineers will work to scale up their technology by developing a continuous conversion process, said Tessonnier, who’s a Carol and Jack Johnson Faculty Fellow and also an associate scientist with the U.S. Department of Energy’s Ames Laboratory.

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Earth-like Planets Have Earth-like Interiors

(February 8, 2016) Every school kid learns the basic structure of the Earth: a thin outer crust, a thick mantle, and a Mars-sized core. But is this structure universal? Will rocky exoplanets orbiting other stars have the same three layers? New research suggests that the answer is yes - they will have interiors very similar to Earth.

"We wanted to see how Earth-like these rocky planets are. It turns out they are very Earth-like," says lead author Li Zeng of the Harvard-Smithsonian Center for Astrophysics (CfA).

To reach this conclusion Zeng and his co-authors applied a computer model known as the Preliminary Reference Earth Model (PREM), which is the standard model for Earth's interior. They adjusted it to accommodate different masses and compositions, and applied it to six known rocky exoplanets with well-measured masses and physical sizes.

They found that the other planets, despite their differences from Earth, all should have a nickel/iron core containing about 30 percent of the planet's mass. In comparison, about a third of the Earth's mass is in its core. The remainder of each planet would be mantle and crust, just as with Earth.

"We've only understood the Earth's structure for the past hundred years. Now we can calculate the structures of planets orbiting other stars, even though we can't visit them," adds Zeng.

The new code also can be applied to smaller, icier worlds like the moons and dwarf planets in the outer solar system. For example, by plugging in the mass and size of Pluto, the team finds that Pluto is about one-third ice (mostly water ice but also ammonia and methane ices).

The model assumes that distant exoplanets have chemical compositions similar to Earth. This is reasonable based on the relevant abundances of key chemical elements like iron, magnesium, silicon, and oxygen in nearby systems. However, planets forming in more or less metal-rich regions of the galaxy could show different interior structures. The team expects to explore these questions in future research.

The paper detailing this work, authored by Li Zeng, Dimitar Sasselov, and Stein Jacobsen (Harvard University), has been accepted for publication in The Astrophysical Journal and is available online.

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Consequences of today's carbon emissions will linger for thousands of years

Melting glaciers like the Equp Sermia glacier in West Greenland, is contributing to sea level rise,

one of the most noticeable effects of global warming. Image courtesy of Michele Koppes,

University of British Columbia.

(February 8, 2016)  The Earth may suffer irreversible damage that could last tens of thousands of years because of the rate humans are emitting carbon into the atmosphere.

In a new study in Nature Climate Change, researchers at Oregon State University (link is external), Lawrence Livermore National Laboratory and collaborating institutions found that the longer-term impacts of climate change go well past the 21st century.

“Much of the carbon we are putting in the air from burning fossil fuels will stay there for thousands of years — and some of it will be there for more than 100,000 years,” said Peter Clark, an Oregon State University paleoclimatologist and lead author on the article. “People need to understand that the effects of climate change on the planet won’t go away, at least not for thousands of generations.”

LLNL’s Benjamin Santer said the focus on climate change at the end of the 21st century needs to be shifted toward a much longer-term perspective.

“Our greenhouse gas emissions today produce climate-change commitments for many centuries to come,” Santer said. “Today’s actions — or inaction — will have long-term climate consequences for generations of our descendants.”

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AZULEJ BY PATRICIA URQUIOLA

(January 8, 2016) This collection is designed to recall hydraulic cement and experiments with an innovative printing technique aimed at mass distribution.

The Azulej patterns combine purposefully diverse languages such memory, geometry and pixels, which develop both lengthways and diagonally. This process develops exponentially and only the first combinations of a long series have been sketched out.

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Cells that show where things are going

Clarity in the cellular thicket. Four classes of nerve cell (Tm9, 4, 1 and 2)

are instrumental in calculating directionally selective signals in T5 neurons (yellow).

© MPI of Neurobiology

(February 6, 2016)  Neurobiologists characterize nerve cells that detect motion by light changes

The ability to see the direction in which something is moving is vital for survival. Only in this way is it possible to avoid predators, capture prey or, as humans in a modern world, cross a road safely. However, the direction of motion is not explicitly represented at the level of the photoreceptors but rather must be calculated by subsequent layers of nerve cells. Scientists from the Max Planck Institute of Neurobiology in Martinsried have now discovered that, in fruit flies, four classes of nerve cell are involved in calculating directionally selective signals. This is strikingly different from mathematical models of motion detection discussed in the literature so far.

When crossing a road, it’s advantageous to know the direction in which nearby cars are moving. However, the individual light sensitive cells in the eye only signal local changes in brightness, whether an image point becomes brighter or darker. The direction of motion is detected in a downstream neuronal network.

Alexander Borst and his team at the Max Planck Institute of Neurobiology have unravelled cell by cell how the brain calculates motion from light changes. Their model is the fruit fly, a master in motion vision, possessing a relatively small brain. Although there are more than 50,000 nerve cells in the area of the fruit fly brain responsible for motion vision, the researchers believe that the network is “simple” enough to allow them to understand the circuitry at the cellular level. In previous studies, they have shown that in flies, similar to vertebrates, motion is detected in two parallel pathways, one for moving bright edges (ON-pathway) and one for moving dark edges (OFF-pathway).

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Shop right: Online shopping might not be as green as people think it is

A study by researchers in the Delaware Center for Transportation provides insight into

the impacts of home shopping on vehicle operations and greenhouse gas emissions.

(February 6, 2015)  Home shopping isn’t new — images from Sears catalogues in the early 1900s show bicycles, banjos, hats, dresses, shoes, long underwear for men, corsets for women, guns, tools, light fixtures, storage trunks, curling irons, metal toys, and even cars and entire house kits.

Shopping malls took a chunk out of home shopping in the mid-20th century, but the Internet brought it back in startling numbers, with close to half of the American population having made online purchases by 2008.

With a few clicks of the mouse or swipes of the screen, people can now order everything from concert tickets, books and craft supplies to home decor, car parts, disposable diapers and groceries.

Logic suggests that online shopping is “greener” than traditional shopping. After all, when people shop from home, they are not jumping into their cars, one by one, to travel to the mall or the big box store.

But a multi-year regional study at the University of Delaware suggests that home shopping has a greater impact on the transportation sector than the public might suspect. The results of the research are documented in a paper, “Impacts of Home Shopping on Vehicle Operations and Greenhouse Gas Emissions,” in the International Journal of Sustainable Development and World Ecology.

Delaware Center for Transportation researchers

Arde Faghri (left) and Mingxin Li.

The study, which focused on the city of Newark, Delaware, was led by Arde Faghri, professor in the Department of Civil and Environmental Engineering and director of the Delaware Center for Transportation (DCT).

The project included data collection through a survey to identify shopping behavior and summary of the survey results by product category, followed by simulation and analysis.

“Our simulation results showed that home shopping puts an additional burden on the local transportation network, as identified through four measures of effectiveness — travel time, delay, average speed, and greenhouse gas emissions,” says co-author Mingxin Li, a researcher at DCT.

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SNAKE GAIT: SCIENCE OBSERVES NATURE TO INVENT NEW WAYS OF MOVING

Credit:  SISSA  (Cicconofri/DeSimone)

(February 5, 2016)  Snake locomotion is a source of inspiration for technology: graceful, silent, adaptable and efficient, it can be implemented on devices designed for the most diverse applications, from space exploration to medicine. A study carried out by a SISSA research group, just published in the Proceedings of the Royal Society A - Mathematical, Physical and Engineering Science, adds to this line of research and proposes a detailed mathematical account of one of the characteristic types of movement adopted by this animal. The model could have applications in the biomedical field, for example to create “smart” scalpels able to slither into tissues causing only minimal damage.

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The Iron Stepping Stones To Better Wearable Tech Without Semiconductors

Iron-dotted boron nitride nanotubes, made in Yoke Khin Yaps� lab at Michigan Tech,

could make for better wearable tech because of their flexibility and electronic behaviors.

(February 6, 2016)  The road to more versatile wearable technology is dotted with iron. Specifically, quantum dots of iron arranged on boron nitride nanotubes (BNNTs). The new material is the subject of a study published in Scientific Reports in February, led by Yoke Khin Yap, a professor of physics at Michigan Technological University.

Yap says the iron-studded BNNTs are pushing the boundaries of electronics hardware. The transistors modulating electron flow need an upgrade.

“Look beyond semiconductors,” he says, explaining that materials like silicon semiconductors tend to overheat, can only get so small and leak electric current. The key to revamping the fundamental base of transistors is creating a series of stepping-stones.

Quantum Dots

The nanotubes are the mainframe of this new material. BNNTs are great insulators and terrible at conducting electricity. While at first that seems like an odd choice for electronics, the insulating effect of BNNTs is crucial to prevent current leakage and overheating. Additionally, electron flow will only occur across the metal dots on the BNNTs.

In past research, Yap and his team used gold for quantum dots, placed along a BNNT in a tidy line. With enough energy potential, the electrons are repelled by the insulating BNNT and hopscotch from gold dot to gold dot. This electron movement is called quantum tunneling.

“Imagine this as a river, and there’s no bridge; it’s too big to hop over,” Yap says. “Now, picture having stepping stones across the river—you can cross over, but only when you have enough energy to do so.”

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Man-made underwater sound may have wider ecosystem effects than previously thought

The langoustine (Nephrops norvegicus) was exposed to sound

by researchers at the University

(February 5, 2016)  Underwater sound linked to human activity could alter the behaviour of seabed creatures that play a vital role in marine ecosystems, according to new research from the University of Southampton.

The study, reported in the journal Scientific Reports published by Nature, found that exposure to sounds that resemble shipping traffic and offshore construction activities results in behavioural responses in certain invertebrate species that live in the marine sediment.

These species make a crucial contribution to the seabed ecosystem as their burrowing and bioirrigation activities (how much the organism moves water in and out of the sediment by its actions) are crucial in nutrient recycling and carbon storage.

The study showed that some man-made sounds can cause certain species to reduce irrigation and sediment turnover. Such reductions can lead to the formation of compacted sediments that suffer reduced oxygen, potentially becoming anoxic (depleted of dissolved oxygen and a more severe condition of hypoxia), which may have an impact on seabed productivity, sediment biodiversity and also fisheries production.

Lead author Martin Solan, Professor in Marine Ecology, said: “Coastal and shelf environments support high levels of biodiversity that are vital in mediating ecosystem processes, but they are also subject to noise associated with increasing levels of offshore human activity. Previous work has almost exclusively focussed on direct physiological or behavioural responses in marine mammals and fish, and has not previously addressed the indirect impacts of sound on ecosystem properties.

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From allergens to anodes: pollen derived battery electrodes

This scanning electron microscope image shows bee pollen studied for

potential use as electrodes for lithium-ion batteries.

Color was added to the original black-and-white image.

(Purdue University image/ Jialiang Tang)

(February 5, 2016)  Pollens, the bane of allergy sufferers, could represent a boon for battery makers: Recent research has suggested their potential use as anodes in lithium-ion batteries.

"Our findings have demonstrated that renewable pollens could produce carbon architectures for anode applications in energy storage devices," said Vilas Pol, an associate professor in the School of Chemical Engineering and the School of Materials Engineering at Purdue University.

Batteries have two electrodes, called an anode and a cathode. The anodes in most of today's lithium-ion batteries are made of graphite. Lithium ions are contained in a liquid called an electrolyte, and these ions are stored in the anode during recharging.

The researchers tested bee pollen- and cattail pollen-derived carbons as anodes.

"Both are abundantly available," said Pol, who worked with doctoral student Jialiang Tang. "The bottom line here is we want to learn something from nature that could be useful in creating better batteries with renewable feedstock."

Research findings are detailed in a paper that appeared Friday (Feb. 5) in Nature's Scientific Reports.

Whereas bee pollen is a mixture of different pollen types collected by honeybees, the cattail pollens all have the same shape.

"I started looking into pollens when my mom told me she had developed pollen allergy symptoms about two years ago," Tang said. "I was fascinated by the beauty and diversity of pollen microstructures. But the idea of using them as battery anodes did not really kick in until I started working on battery research and learned more about carbonization of biomass."

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A new-generation exoskeleton helps the paralyzed to walk

Steven Sanchez, who was paralyzed from the waist down after a BMX accident, wears SuitX’s

Phoenix. “If I had this it would change a lot of things,” he says. (Photo courtesy of SuitX)

(February 5, 2016)  Until recently, being paralyzed from the waist down meant using a wheelchair to get around. And although daily life is more accessible to wheelchair users, they still face physical and social limitations. But UC Berkeley’s Robotics and Human Engineering Laboratory has been working to change that.

The robotics lab, a team of graduate students led by mechanical engineering professor Homayoon Kazerooni, has been working for more than a decade to create robotic exoskeletons that allow those with limited mobility to walk again.

This week, a new, lighter and more agile exoskeleton, for which the Kaz lab developed the original technology, was unveiled earlier this week: The Phoenix, by SuitX, a company that has spun off the robotics lab. Kazerooni is its founder and CEO.

The Phoenix is lightweight, has two motors at the hips and electrically controlled tension settings that tighten when the wearer is standing and swing freely when they’re walking. Users can control the movement of each leg and walk up to 1.1 miles per hour by pushing buttons integrated into a pair of crutches. It’s powered for up to eight hours by a battery pack worn in a backpack.

“We can’t really fix their disease,” says Kazerooni. “We can’t fix their injury. But what it would do is postpone the secondary injuries due to sitting. It gives a better quality of life.”

Kazarooni and his team have developed a series of exoskeletons over the years. Their work in the field began in 2000 with a project funded by the Defense Advanced Research Projects Agency to create a device, now called the Berkeley Lower Extremity Exoskeleton (BLEEX), that could help people carry heavier loads for longer. At that time, Kazerooni also realized the potential use for exoskeletons in the medical field, particularly as an alternative to wheelchairs.

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Read more about SuitX’s Phoenix suit in the MIT Technology Review >>