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571
EEE / Converted milk proteins clean pollution, strike gold
« on: November 20, 2016, 06:38:24 PM »
Tenacious proteins similar to those implicated in Alzheimer’s disease could help purify polluted water.

A newly designed membrane uses thin amyloid protein fibers to pull heavy metals and radioactive wastes out of water. The membranes can capture more than their own weight in some contaminants, scientists in Switzerland report January 25 in Nature Nanotechnology.

“I think what’s really interesting in this study is that it actually used a protein material, which is novel,” says Qilin Li, an environmental engineer at Rice University in Houston who was not involved in the study. Specifically, the team converted milk proteins into fibers of durable amyloid protein. Other amyloids are infamous for building up in the brains of Alzheimer’s patients, but the team put their amyloids’ sticky tendrils to different use.

Clean up crew
Amyloid-carbon membranes filtered over 99.9 percent of lead pollutants out of a contaminated solution, bringing the overall concentration of pollutant particles below a measurable threshold of 0.02 parts per million — and turning a once-grimy liquid clear (right).


S. BOLISETTY AND R. MEZZENGA/NATURE NANOTECHNOLOGY 2016

When paired with strong, porous carbon in a membrane, the lab-made amyloids successfully filtered over 99 percent of toxic materials out of solutions that mimicked severely polluted waters, the scientists report. The amyloids trapped particles of lead and mercury at a molecular site that is involved in turning the original milk protein into its pasty form. Radioactive waste particles also got tangled in the membranes. And the membranes snagged gold contaminants, which the team found could later be recovered and purified. A membrane with less than 6 milligrams of amyloids could trap 100 milligrams of gold, the scientists report.

It’s exciting to see that the amyloids can hold more than their own mass in heavy metal particles, says Li. More typical membrane materials, she says, would grab only a fraction of their weight in pollutants.

The membranes could be developed for small- or large-scale water purification units, says study coauthor Raffaele Mezzenga, a physicist at ETH Zurich. Mezzenga estimates the technology would cost roughly one dollar per every thousand liters of water filtered. And a membrane can recover hundreds of times its own value in precious metals, Mezzenga says. The membrane design is simple and flexible, and could be adjusted to optimize cleanup or metal recovery, he says.

Li says the membranes will need to be tested and optimized in real polluted waters, which may have chemical complications such as high or low acidities. But the amyloids’ performance is encouraging, she says, and the proteins’ contaminant-trapping capabilities could inspire other researchers developing contaminant filters.

572
EEE / Online reading behavior predicts stock movements
« on: November 20, 2016, 06:37:59 PM »
Web surfing patterns as people read financial news can be used to make accurate predictions of stock movements from a few minutes to up to a couple of hours in advance, a new study suggests. With further development, the technique may be useful to financial authorities as they monitor markets and seek to fend off emerging crises.

A team of physicists led by Gabriele Ranco of the IMT Institute for Advanced Studies in Lucca, Italy, suspected that better stock predictions might be made by looking at more than the positive or negative sentiment expressed in an article about a particular company. Another key indicator might be how many people actually click on links to those articles, a sign of the social influence of the article and how much its readers are paying attention.

The team used data collected over a yearlong period in 2012 and 2013 from Yahoo! Finance, an online portal for financial news and data. Looking at the 100 U.S. companies with the most frequent mentions in news articles, the researchers calculated a measure of sentiment for each article. They then weighted that measure to reflect readers’ behavior: Articles counted for more if more readers clicked on links to them.

The result was a moment-by-moment signal for each company showing how sentiment and interest fluctuated during the day, and how strongly. The researchers then compared these signals with actual market fluctuations of prices, volume and volatility for the 100 different stocks. The signals offer a significantly improved predictive capacity for stock movements, even for movements only a few minutes later, the researchers conclude January 25 in PLOS ONE.

Rosario Mantegna, an expert in mathematical finance at the University of Palermo in Italy, suggests that this method could prove useful for financial authorities worried about the potential for explosive financial events —a bank run triggered by a surge of investor fear, for example. “Monitoring in this way could provide some useful indicators,” he says.

An important aspect of the new work is its ability to monitor web activity on timescales as short as a minute, says study coauthor Guido Caldarelli, a physicist also at the IMT Institute for Advanced Studies. In principle, he says, this kind of analysis could be carried out in real time if financial authorities had access to the data.

More generally, says Caldarelli, the study illustrates the potential of “big data” to provide new means to detect broad social patterns of belief —a problematic task in areas ranging from public health to political polling. “Questionnaires are slow and people don't always give their real views,” he says. “An advantage of web data is that people tend to be more sincere when they’re browsing.”

573
EEE / Machine triumphs in strategy game
« on: November 20, 2016, 06:37:33 PM »
In a victory that rivals the computer Deep Blue’s 1997 win over chess champion Garry Kasparov, a computer has now bested a professional human player in the classic strategy game Go.

The computer program, called AlphaGo, trounced Fan Hui, the reigning European Go champion, 5 games to 0, researchers report in the Jan. 28 Nature.

Go, a game that originated in China more than 2,500 years ago, is much more complicated than chess, with an order of magnitude more possible opening moves, study coauthor Demis Hassabis of Google DeepMind said at a news conference. Many researchers thought a computer wouldn’t be able to beat a top human player for another five or 10 years, he said.

AlphaGo learned to play Go from experience. But the program needed much more practice than humans do to become an expert, Hassabis said: millions of games, rather than thousands.

In March, the program will put its skills to the ultimate test in a match against South Korean Lee Sedol, considered the world’s best Go player.

574
EEE / Tracking health is no sweat with new device
« on: November 20, 2016, 06:36:42 PM »
Fitness trackers just got an upgrade.

A new electronic health-monitoring device can sense a person’s temperature, analyze chemicals in a drop of sweat, and send the data wirelessly to a smartphone app — all in a package about the size of a few postage stamps.

The gadget could help athletes instantly gauge their hydration level, or give scientists an easy and noninvasive way to collect data for medical studies.

Researchers have built sweat sensors before, but the new device “just represents a whole nother level of sophistication,” says materials scientist John Rogers of the University of Illinois at Urbana-Champaign.

Previous sensors have detected only a single chemical. The new sensor can measure four chemicals — glucose, lactate, sodium and potassium — simultaneously ­and in real time, Ali Javey and colleagues report January 27 in Nature.

Traditional electronics rely on “brains” made of tiny circuits laid out on silicon chips. “But the problem with silicon chips is that they’re way too small and rigid,” says Javey, an electrical engineer at University of California, Berkeley.They’re great for data processing — not for making sensors that hug the skin. For that, rubbery electronics that can twist and flex are ideal (SN: 11/17/12, p. 18). But they don’t have the processing power of silicon-based versions.

575
EEE / Pill measures gut gas
« on: November 20, 2016, 06:36:09 PM »
Gas concentrations in the gut can reveal secrets about digestive tract health, and may be skewed in conditions such as irritable bowel syndrome. But sampling gas in breath or stool doesn’t give the most accurate picture of what’s bubbling in the intestines. Australian researchers have designed a swallowable gas-sensing capsule that could someday provide an inside look at the gases in the human gut.

Each capsule contains a sensor for hydrogen, carbon dioxide and methane. Every five minutes, as it travels through the digestive system, the capsule sends updates about its gassy surroundings to a smartphone. Too much methane or hydrogen in the gut, the scientists say, could reflect digestive problems.

The team tested the capsule in pigs, which have gas-generating gut microbes similar to humans’. In two pigs fed a high-fiber diet, the pills detected increased carbon dioxide levels in the stomach and small intestine after eating, a shift not seen in two pigs fed a low-fiber diet, the researchers noted in the January Gastroenterology.

The capsule is a proof of concept that the researchers are working to shrink down. The preliminary design — about as long as a Brazil nut — may still be a hard pill to swallow.

576
At the 2013 trials of DARPA’s robotics competition in Florida, a high-tech robot named Hubo had just about completed a tricky challenge: climbing up a ladder roughly the height of a small elephant.

Hubo, a 5-foot-tall walking bot, was pitting its skills against a slew of formidable contenders, all in a contest designed to simulate what rescue robots might face in a disaster. Hubo had already climbed eight of the ladder’s nine rungs — more than any other bot in the competition.

Then, Hubo tipped over and plunged off the ladder, dangling from a safety wire like a dancing marionette.

The bot’s rise and fall illustrates the state of humanoid robotics today, suggests “Rise of the Robots,” a documentary from the TV series NOVA that will air February 24 on PBS. Roboticists have created all sorts of fancy machines that can do all sorts of impressive things, such as cooking, dancing and even folding laundry. But getting these bots ready for rescue work — walking over rubble, picking up debris and driving cars, for example — is an entirely different story.

In fact, just getting bots to work outside the lab is tough, say several researchers interviewed in the show. “The real world is like the wild, Wild West,” says Tony Stentz, a roboticist at Carnegie Mellon University in Pittsburgh.

“Rise of the Robots” introduces viewers to Stentz’s team’s bot, a roughly 180-kilogram behemoth named CHIMP, and a suite of other people-sized machines. The documentary follows these robots as they tackle tasks in DARPA’s competition, which ended in 2015. Seeing the bots in action is thrilling, but their awkwardness is eye-opening. Humanoid robots have yet to master upright walking on two legs, like people do. It’s one of the trickiest problems facing modern roboticists. In the competition, robots trudge slowly, topple over backward and stand motionless for minutes at a time.

Still, there’s plenty to ooh and ah over. The documentary takes a round-the-world tour of some of the hottest robotics labs. In London, a black robotic hand wiggles slim mechanical fingers nearly as deftly as a human. In Florida, a hulking humanoid bot named Atlas balances on one foot, waving arms in the air like the Karate Kid.

At the end of the hour-long show, “Rise of the Robots” brings viewers back to Hubo. The robot has a slick new look and is now competing in the competition’s finals. The action is still slow, but viewers will be on the edge of their seats rooting for machines that are steps closer to becoming more human, if not yet there.

577
EEE / New app puts an earthquake detector in your pocket
« on: November 20, 2016, 06:34:49 PM »
WASHINGTON — If you need to detect earthquakes, there’s an app for that. Seismologists have harnessed the motion-sensing accelerometers built into smartphones to detect tremors. The app, called MyShake, could eventually provide early warning of approaching quakes in regions lacking sophisticated seismometer networks, Richard Allen, a seismologist at the University of California, Berkeley, said February 11 at the annual meeting of the American Association for the Advancement of Science.

MyShake monitors a smartphone’s movements. The software differentiates between everyday motion, such as a phone jostling in a pocket, and vibrations caused by an earthquake. The system monitors whether smartphones running the app in the same area report a quake (SN: 4/19/14, p. 16). One day, the system could then send earthquake alerts to users’ phones, Allen said.

The researchers tested the app by placing smartphones on special vibrating tables that mimic real temblors. MyShake can accurately record earthquakes of magnitude 5 or above within 10 kilometers of the epicenter, the researchers report February 12 in Science Advances. Had MyShake been deployed before the April 2015 Nepal earthquake, the system could have provided about 20 seconds of warning before the tremors struck Kathmandu, where most fatalities occurred (SN: 5/16/15, p. 12), the researchers estimate.

578
EEE / New clues illuminate mysteries of ancient Egyptian portraits
« on: November 20, 2016, 06:34:11 PM »
WASHINGTON — Scientists are getting a clearer picture of how ancient Egyptians painted lifelike portraits that were buried with mummies of the depicted individuals. These paintings sharply departed from Egyptians’ previous, simpler artworks and were among the first examples of modern Western portraits, archaeologist and materials scientist Marc Walton reported February 14 at the annual meeting of the American Association for the Advancement of Science. The “mummy portraits” date to more than 2,000 years ago, when the Roman Empire controlled Egypt.

Three such portraits of Roman-era Egyptians, found more than a century ago at a site called Tebtunis, were created by the same artist, said Walton, of Northwestern University in Evanston, Ill. Identities of the boy and two men in the portraits are unknown. Separate computerized analyses of colors and shapes in the stylistically similar paintings revealed that brushstrokes of the same width were used to apply the same pigment mixes to different parts of each portrait. All three portraits, for instance, included a purple shoulder sash that the artist painted with a blend of indigo and a red pigment derived from the madder plant.

Many pigments in the portraits probably came from Greece, Walton said. Ancient Greeks’ naturalistic painting style influenced the Egyptians’ switch to portrait painting, he suggested. But the paintings also suggest even more distant influences: Walton’s team traced red lead used in Egyptian pigments to Spain and wood on which the portraits were painted to Central Europe. Egyptians traded over long distances by 3,400 years ago (SN: 1/24/15, p. 8).

Walton plans to study 12 more Egyptian mummy portraits, as well as paintings of women in pink garb and ones of military gods that have also been found in Egyptian tombs.

579
EEE / After 75 years, plutonium is still NASA’s fuel of choice
« on: November 20, 2016, 06:33:20 PM »
Plutonium’s 25th year — The 25th anniversary of the discovery of plutonium was celebrated in February…. Plutonium, a highly radioactive metallic element, is made by bombarding uranium with neutrons…. The nuclear energy released by the fissioning of one pound of plutonium is equal to the explosive effect of 20 million pounds of TNT.… Plutonium is now emerging as the nuclear energy source of the future. It was the first and is still the only radioisotope producing power in space and is in use now on four satellites. — Science News Letter, March 5, 1966

Update
Unlike Europe, the United States has been slow to use plutonium as a power source on the ground. But the element still drives NASA’s long-distance missions, recently fueling the New Horizons probe on its trip to Pluto (the element’s namesake). U.S. nuclear reactors could begin using plutonium to generate electricity if construction is completed on a South Carolina facility. The site will make nuclear fuel with small amounts of plutonium extracted from retired Cold War–era weapons.

580
EEE / New carbon cluster has high storage capacity
« on: November 20, 2016, 06:32:30 PM »
Researchers have identified a mysterious lab-made material as a new form of carbon. 

Carbon honeycomb, a three-dimensional cluster of carbon sheets, can trap large amounts of gas within six-sided cells. The newly described structure could be used to store gases or liquids, or as a building material for more complex compounds, Ukrainian researchers report February 5 in Physical Review Letters.

Electron microscope images helped uncover the new structure, which was first created in 2009 by vaporizing thin carbon spindles in a vacuum. Subsequent tests of the nanometers-thick film revealed that the substance had different density and light-scattering properties than known forms of carbon like graphite or fullerenes. Carbon honeycomb cells might link up with cylindrical carbon nanotubes, the researchers say, but unlike nanotubes, the new structure holds up for months in a vacuum without degrading. The honeycomb also absorbs unusually large amounts of gases, including carbon dioxide and xenon, holding around twice as many gas molecules as nanotubes can.

Future research should aim to produce a more uniform carbon honeycomb, says Nina Krainyukova, a physicist at the National Academy of Sciences of Ukraine. In current versions, some chambers are five-sided and their arrangement is random.

The structure has interesting potential as a stable, supportive material, says MIT chemical engineer Michael Strano. But he says more data about the honeycomb’s physical and chemical properties are needed.

581
EEE / New type of catalyst could aid hydrogen fuel
« on: November 20, 2016, 06:31:34 PM »
BALTIMORE — For a long time now, hydrogen has been the fuel of the future. A new idea for extracting hydrogen from water might help that future arrive a little sooner.

Today, producing hydrogen requires burning fossil fuels or using water-splitting catalysts that work relatively inefficiently, says physicist Arvin Kakekhani of Yale University. But Kakekhani and Sohrab Ismail-Beigi, also at Yale, identified a strategy using materials known as ferroelectric oxides to catalytically separate hydrogen from oxygen more effectively.

Catalysis requires a surface that both grips a water molecule in order to split it and releases the hydrogen atoms separated in the process. Ordinary catalysts must compromise between these two competing qualities. But a ferroelectric substance such as lead titanate can be prepared so that heat can switch it from a state suitable for splitting to another state good at releasing, computer simulations showed. Researchers therefore should be able to design a cycle of states that extracts hydrogen efficiently, Kakekhani reported March 17 in a news conference at a meeting of the American Physical Society.

“It’s a conceptual study that should be experimentally confirmed,” he said. A report on the work was also published online March 8 in the Journal of Materials Chemistry A.

582
EEE / Machine makes drugs on demand
« on: November 20, 2016, 06:31:06 PM »
A new refrigerator-sized factory can rapidly pump out a diverse assortment of drugs on demand.

Researchers designed the system to offer a speedy alternative to large-scale pharmaceutical production. Rejiggering chemical inputs and the device’s collection of tanks and tubes allowed the team to produce four different drugs: an anesthetic (lidocaine), an antihistamine (Benadryl), an antianxiety medication (Valium) and an antidepressant (Prozac). The self-contained system was equipped to mix, heat, pump and purify ingredients into hundreds or thousands of doses of pharmaceutical-grade compounds. Making each medication took roughly 12 to 48 hours, an international team of researchers reports in the April 1 Science.

For now, the device makes only liquid medications. But the work is a step toward overcoming limitations of cumbersome drug-making supply chains by developing automated tools that make medications on demand (SN: 8/22/15, p. 22).

583
EEE / Lasers unveil secrets and mysteries of Angkor Wat
« on: November 20, 2016, 06:30:45 PM »
Smartphone-toting pilgrims regularly stream into northern Cambodia from all over the world. Their destination: Angkor Wat, a medieval temple that’s famous for massive towers and majestic stone carvings of Hindu gods, spirits and mythological battle scenes. The site, considered the world’s largest religious monument, drew more than 2.3 million visitors in 2014.

Angkor Wat’s sightseers encounter a study in contrasts. This architectural wonder of human civilization ascends skyward, on the verge of being engulfed by nature below. Tourists walk along a path that crosses over a moat and through the temple’s western side, the one entrance cleared of vegetation. Lush forest stops just short of the rest of the structure. Outside the moat, trees, thick ground cover and ponds dominate the landscape.

While adventurous visitors snap pictures, scientists are using high-tech approaches to uncover Angkor Wat’s hidden side, long obscured by all that vegetation. After more than a century of research on the parts of Angkor Wat that are visible with the naked eye, many scientists assumed that the site was a sacred city contained within the bounds of a square moat. But even though its name roughly translates as “temple city,” new finds show that Angkor Wat was not a sacred city at all. It was a gigantic temple connected to residential districts, canals and other structures that stretched beyond the moat and blended into a sprawling city called Greater Angkor, which covered about the same area as Berlin or Columbus, Ohio.


Forest and vegetation surround Angkor Wat (top). A lidar map (bottom) stripped away ground cover to reveal previously unknown archaeological features of the temple and its surroundings.
D. EVANS ET AL/PNAS 2013

Angkor Wat’s unveiling by modern laser technology began in April 2012. Archaeologist Damian Evans of Cambodia’s Siem Reap Center and several colleagues made daily helicopter flights for almost two weeks over a 370-square-kilometer area around the temple. The helicopter carried $250,000 worth of special equipment that fired millions of laser pulses every few seconds at the forest below. A small percentage of those pulses zipped in between trees and foliage to the forest floor. The Earth’s hard surface bounced those laser shots back to a sensor on the helicopter. This technique, known as light detection and ranging, or lidar for short, picked up differences in the contours of the land now obscured by jungle. With the findings, researchers could draw a picture of city blocks, residential areas, dried-out ponds and other archaeological remains. Results gleaned from lidar and from new ground-based investigations appeared in the December 2015 Antiquity.

Lidar has been around since the early 1960s. Scientists have used it to measure pollutants in the atmosphere, map shorelines and guide robotic and manned vehicles around obstacles. Lower costs over the last decade have made the technology accessible to archaeologists.

With their laser eye in the sky, Evans and colleagues uncovered big surprises at Angkor Wat. Just beyond one side of the roughly 1.3-kilometer-square moat surrounding the temple, the researchers found six massive and mysterious lines of earth arranged in precise coils — as well as adjacent areas where later canal construction had apparently destroyed two more coiled mounds. These Khmer creations resemble the spiraling paths of labyrinths. Lidar-guided excavations within the moat’s boundary upended ideas about who lived on temple grounds. Rather than religious or political bigwigs, residents were workers who kept the place running. And on-the-ground research found evidence of unexplained towers, built and then demolished during Angkor Wat’s construction, as well as defensive platforms used, perhaps, to fight off invaders.

“It’s an embarrassingly exciting time for archaeologists who study Angkor Wat,” says University of Sydney archaeologist Roland Fletcher. “Researchers have driven and walked over many of these new discoveries for a century.” Fletcher directs the Greater Angkor Project, which combines remote sensing technology with archaeological digs.

If Angkor Wat blended into Greater Angkor’s 1,000 square kilometers of urban sprawl, so did hundreds of other temples and shrines of lesser grandeur built by rulers of Southeast Asia’s Khmer Empire from the ninth to 15th centuries, he says.

“There was nothing like Greater Angkor until the advent of 19th century industrial cities,” says Fletcher, who estimates it held about 750,000 residents in the 12th and 13th centuries. Cities of around 1 million people arose in China by the ninth century, but those metropolises covered one-half or less the area of Greater Angkor. Spread-out cities in the mold of Greater Angkor became more common in the 1800s as trains and cars made long-distance travel easier. But discoveries at Greater Angkor shatter a long-standing assumption that urban sprawl was impossible without mechanical forms of transportation, he says.

584
EEE / How to trap sperm
« on: November 20, 2016, 06:29:38 PM »
New sperm-catching beads could someday help prevent pregnancy — or enable it.

Researchers created microscopic polymer beads that mimic unfertilized eggs and trap passing sperm. The beads are coated in the sperm-binding section of a protein called ZP2. In mammals, ZP2 is found in membranes around unfertilized eggs; sperm must bind to the protein before entering the egg.

The beads could be used as short-term contraceptives, Jurrien Dean of the National Institutes of Health in Bethesda, Md., and colleagues report in the April 27 Science Translational Medicine. In the laboratory, human sperm attached to the beads within five minutes. The researchers then mixed 100,000 human sperm with 1.5 million beads and 28 mouse eggs containing human ZP2 proteins. After 16 hours, only one sperm reached an egg.

In another experiment, beads coated with mouse ZP2 delayed pregnancy when injected into the uteruses of mating female mice. Bead-free mice took just over 28 days, on average, to conceive and give birth; bead-treated mice didn’t have babies for nearly 73 days on average. The beads didn’t appear to cause swelling or damage, and treated mice were able to give birth again within five months.

The beads could also help combat infertility. In an egg-penetration test, researchers gently detached bead-captured sperm and pitted those sperm against a control batch of sperm that had not been exposed to the beads. More than half of eggs (mouse eggs with human ZP2) exposed to the bead-selected sperm ended up with three or more sperm attached to them; none of the eggs exposed to the control group snagged three or more sperm. In fact, the control group failed to penetrate 38 out of 50 eggs. So the beads could someday be used to select healthy sperm for assisted reproduction, the researchers say.

But it’s not clear if the ability to bind to ZP2 necessarily indicates a healthy sperm, says Andrew La Barbera, chief scientific officer of the American Society for Reproductive Medicine in Birmingham, Ala. “Sperm selection is a very complex undertaking because of the fact that sperm are very complex,” he says. “We don’t know what makes a good sperm.”

Contraception might be a more reasonable future use for the beads, although allowing fertilization of one in 28 eggs is underwhelming, La Barbera says. Birth control should be closer to 99.9 percent effective. “It only takes one sperm to fertilize an egg,” he says. Still, the beads’ performance at blocking pregnancy in mice seems promising, La Barbera says. Future experiments would need to determine if the beads are safe and effective in women, and how many beads are needed to prevent conception.

Dean notes that the study is a proof of principle. Many unknowns must be evaluated before using the beads for birth control, including the side effects of long-term use, he says. “Although promising, we are a long way from translating these basic laboratory observations into useful clinical applications that provide people with better reproductive choices.”

585
EEE / Insect-sized bot is first to both fly, land
« on: November 20, 2016, 06:27:32 PM »
Houseflies stretch their legs to land. Bumblebees hover, then slowly descend. Now, insect-sized flying robots have a way to stick the landing, too.

A tiny aerial bot about the size of a bee (nicknamed RoboBee) uses static electricity to cling to the underside of a leaf and perch on other materials, study coauthor Robert Wood of Harvard University and colleagues report in the May 20 Science.

RoboBee, a bot with shiny, flapping wings and four pinlike legs, is the first of its size that can fly, perch on a surface and then take off again. This energy-saving feat could one day extend mission time in search and rescue operations, the researchers say.

For robots, tackling the problem of flight has been easier than figuring out how to land. “Engineers have been trying to build perching mechanisms for flying robots nearly as long as we have been creating flying robots,” Wood says.


CHARGED UP Affixed to the top of a tiny aerial robot about the size of a quarter, a circular disk holds electrodes that can be charged, letting the bot cling to overhanging surfaces.
M.A. GRAULE ET AL/SCIENCE 2016

Researchers have had success with bigger, bird-sized bots (SN: 2/7/15, p. 18), but their landing mechanisms are tricky to scale down. For the microbot, Wood and colleagues wanted something simple: lightweight and without moving parts.

The team created an “electroadhesive” patch with electrodes that can be charged, letting the patch stick to different surfaces, like a balloon sticking to the wall after being rubbed on someone’s hair.

Switch the electrodes on and the patch, a circular disc on top of the robot, helps RoboBee hang out on overhanging pieces of glass or plywood, for example. Switch the electrodes off and the bot detaches, free to fly again. The sticky contraption lets RoboBee rest between flights: The bot used about a thousandth as much energy perching than hovering, the researchers found.

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