A new type of soft robot can go under the knife and make a full recovery in about a day.

Researchers fashioned a robotic hand, gripper and muscle from self-healing rubbery material. To test their robots’ resilience, the engineers sliced each with a scalpel, then put them in an oven. After cranking up the heat to 80° Celsius, baking the bots for 40 minutes, then cooling them to room temperature, the researchers found that all three bots’ cuts had completely closed up. Twenty-four hours later, the machines had regained at least 98 percent of their original strength and flexibility, the researchers report online August 16 in Science Robotics.
Incisions broke bonds between two chemical ingredients that make up the material, furan and maleimide. At higher temperatures, these chemical compounds can also split up, as well as move around more easily. So as the researchers cooled the material, the compounds were able to re-bond with those on the other side of an incision.
“This material could heal, in theory, an infinite number of times,” says study coauthor Bram Vanderborght, an engineer at Vrije University Brussels.

The work helps address a major limitation of squishy, flexible robots — which are better suited than their traditional, rigid counterparts for navigating rough terrain and handling fragile objects, but are vulnerable to punctures and tears. Self-healing machines could pave the way for creating more durable, reusable soft bots.

Getting rid of bodily wastes during long space flights is a problem…. A bizarre possible solution … involves whipping the wastes in with some other ingredients to produce the most unusual rocket fuel…. The four ingredients — carbon, ammonium, nitrate and aluminum — and the waste material are just blended together, and they’re ready to go…. [The material] would probably be used to help a spacecraft change position or to nudge a long-life space station occasionally to keep it up in orbit. –Science News, September 2, 1967
Update
Researchers are still trying to figure out how to turn astronaut excrement into something useful. Another process proposed in 2014 would use microbes to convert the waste and other organic material into fuel. But waste might have other uses that would be especially helpful during long-term flights. Synthetic biologists at Clemson University in South Carolina are working with NASA to use algae and genetically modified yeast to turn astronaut urine into 3-D printable plastics and nutritional omega-3 fats.

Sure, students in the classroom have to remember facts, but they also have to apply them. Some research efforts to enhance learning zero in on methods to strengthen memory and recall, while others bolster students’ abilities to stay on task, think more fluidly and mentally track and juggle information.

But there’s a catch. The science behind student learning is so far based on carefully controlled studies, primarily with college students. Do the same approaches work with younger students? Will they work in a classroom of 25 or 30 kids of varying abilities?
These are questions researchers are asking now, says Erin Higgins of the U.S. Department of Education’s National Center for Education Research. Moving from the lab to a classroom, with all its disruptions and distractions, is key for pinning down what works, under what conditions and for whom. In the process of tweaking some of the most promising tools and strategies for classroom use, educators hope to find ways to help low-performing students gain skills that already pay off for their more successful peers. The efforts described here draw on new, innovative training methods to boost learning in K-12 classrooms. Higgins calls them “great examples” of the work under way.

Recall with cues
For college students, “free recall” is one of the most effective ways to make new knowledge stick, says psychologist Jeffrey Karpicke of Purdue University in West Lafayette, Ind. Students who read a passage and then jotted down details they remembered from the material recalled about 50 percent more information a week later than did students who just reviewed the material.
The trick for younger learners, Karpicke found, is to provide cues to help recall, without making the task too easy. After studying lists of unrelated words (banana and football), fourth-graders either restudied the words or practiced retrieving them from memory before taking a free recall test. Findings, published last year in Frontiers in Psychology, show that children at all reading levels remembered at least 25 percent more words when they practiced retrieving with the help of some cues compared with just rereading the lists.

With psychologist Michael Jones of Indiana University Bloomington, Karpicke is creating a computer-based self-test to help kids hone their retrieval skills. Students might have to answer fill-in-the-blank questions or rearrange scrambled words. Teachers will be able to tailor the tests to the curriculum. Parts of the program are being tested in schools in West Lafayette this year. The program gets harder as children succeed but easier if they struggle. “It’s important that students experience success,” Karpicke says, while keeping the task challenging.
Hold that thought

Working memory, which allows a person to hold on to information long enough to use it, is often a weakness in children who struggle with math, says educational psychologist Lynn Fuchs of Vanderbilt University in Nashville.
Handy for remembering a phone number long enough to find a pen to write it down or for multiplying numbers in our heads, working memory can be strengthened through exercises that put progressively tougher demands on it. But general training may not be enough to help struggling math learners, according to a 2015 review of school-based programs, published in the Journal of Educational Psychology.

Fuchs has developed a routine that embeds working memory exercises within math lessons. Designed for second-graders at risk for math difficulties, the program has students focus on key words in a word problem and hold the words in mind while breaking the problem into smaller segments and choosing the right math tools to solve the problem.

Aiming to catch young learners before they fall behind, researchers are testing the program in Nashville classrooms this school year.

Sum of the parts
Researchers typically test one new strategy in isolation, but in real classrooms, educators may try more than one approach at once. Jodi Davenport of WestEd, a San Francisco–based education research and development group, codirected a multi-institutional effort to revise a seventh-grade math curriculum using a handful of promising strategies.
Lessons were spaced out to expose students to key concepts or procedures multiple times and were combined with frequent quizzes. Graphics accompanied examples of how to work a problem, to strengthen the connection between the visual and verbal material. Researchers trained 181 teachers at 114 schools and then tracked 2,465 students in 22 states over a full school year.

Strategies such as showing incorrect examples along with correct ones (to point out common errors) and removing distracting information were especially helpful to underperforming students, Davenport says. Students with lower pretest scores scored higher on posttests in six of eight math units when using the new curriculum versus the traditional materials, the researchers reported in March in Washington, D.C., at the Society for Research on Educational Effectiveness meeting.

Testing the program in so many schools amid teacher turnover and other real-life challenges made control­ling for variance hard, so the data weren’t as robust as researchers had hoped. But there appeared to be improvements, particularly in girls, underrepresented minorities, English-language learners and special education students. The methods work by helping students focus and link related info, Davenport speculates. “Successful students have these skills,” she says. “They’ve developed strategies … to focus their attention and employ problem-solving skills as they work through a problem.” She hopes to help teachers give struggling kids those same skills.

Granting executive powers
Students must learn to stay focused in the face of distraction, to direct actions toward a goal and to hold what they have just seen or heard in mind while they work with it. These abilities are part of a set of cognitive skills called executive function.
There’s strong evidence that well-designed video games can improve executive function among teens and adults, says psychologist Bruce Homer of the City University of New York. “But we need more research to determine if — and how well — these skills transfer to the classroom to … improve academic performance,” he says. With psychologist Richard Mayer of the University of California, Santa Barbara, and Jan Plass of New York University’s game design center, Homer is developing a series of video games for students from middle school to college. Each game targets a specific area of executive function, such as shifting attention or avoiding distractions.

The first of three games is in testing, assigned as homework for 300 kids in Santa Barbara and New York City schools. In the game, students must quickly adapt to rule changes as aliens land on Earth and request help gathering supplies. Preliminary findings show that after eight 30-minute sessions, players of the alien game showed substantially greater improvements in ability to shift strategies in standard cognitive tests compared with students who played a different game. This fall, researchers plan to study whether gains in executive function from game play can improve actual performance in specific academic areas.

Nearly 1 in 5 adolescents has suffered at least one concussion, according to a survey of U.S. teens. And 5.5 percent reported two or more concussions diagnosed in their lifetimes, researchers report in the Sept. 26 JAMA.

About 13,000 eighth-, 10th- and 12th-graders participated in the 2016 Monitoring the Future survey, an annual national questionnaire of adolescent behavior and health given in schools. Among other questions, teens were asked whether they had ever had a head injury that was diagnosed as a concussion — 19.5 percent replied “yes.” Those teens were more likely than others to play competitive sports and be male, white and in a higher grade.

Previous studies have found that kids taking part in contact sports are at higher risk of suffering a concussion. These new data on actual prevalence of concussions, though self-reported, are important, say the authors, for crafting prevention efforts that protect teens from injuries.

Hard-boiled eggs are a dish best served cold.

When quickly reheated in a microwave and then pierced, the picnic staple can explode with a loud bang in a shower of hot, rubbery shrapnel. But this blast is far more likely to make a hot mess than hurt your hearing, according to research presented December 6 at the Acoustical Society of America meeting in New Orleans.

That distinction isn’t as odd as it might sound. In a lawsuit, a man claimed to have suffered burns and hearing damage after a microwaved, hard-boiled egg exploded in his mouth at a restaurant. Researchers from Charles M. Salter Associates, Inc. in San Francisco called as expert witnesses couldn’t find scientific papers backing up the claim that an egg could burst with enough vigor to cause hearing loss — just a lot of YouTube videos documenting eggsplosions.
So the researchers microwaved peeled hard-boiled eggs in water on high power for three minutes.

The eggs were “uncooperative,” study coauthor Anthony Nash said in a news conference. Some exploded in the microwave, while others wouldn’t explode at all. But of nearly 100 eggs tested, 28 exploded outside of the microwave after being poked with a meat thermometer. From 30 centimeters away, the sound pressure from those explosions ranged from 86 to 133 decibels.

The median sound pressure level recorded, 108 decibels, is about the same as that at an average rock concert. Continuous exposure to that noise level could damage hair cells inside ears that respond to sound. The National Institute for Occupational Safety and Health sets recommended exposure limits for sound pressures above 85 decibels, says William Murphy, a researcher at NIOSH who wasn’t part of the study. But those limits are based on daily exposure over years, he says.
A burst egg’s boom, on the other hand, lasts just milliseconds — not long enough to do much harm. “The likelihood for hearing damage from a single exploding egg was very low,” Nash said.

The lawsuit was settled out of court before Nash and his colleagues conducted the second phase of the study – considering how sound hits your ears when it’s coming from inside your mouth. An in-mouth explosion might send slightly more sound pressure to the ears, Nash says, but still probably not enough to cause lasting damage as a one-time accident.

A peeled egg probably explodes when pockets of water trapped in the yolk become superheated — hotter than the boiling temperature of water without actually bubbling, Nash suggested. When disrupted, say by a fork or a tooth, the water pockets spontaneously boil, bursting through the squishy egg white and sending bits flying. (It’s the same phenomenon that can occasionally make microwaved coffee spurt out of the mug onto your clean work clothes.)

A bigger risk than the noise might be the heat. Nash and his colleagues measured the temperature of yolks in eggs that didn’t burst. Those temperatures were, on average, 12 degrees Celsius above the surrounding water bath, which was often close to boiling.

This year, gene therapy finally became a clinical reality. The U.S. Food and Drug Administration approved two personalized treatments that engineer a patient’s own immune system to hunt down and kill cancer cells. The treatments, the first gene therapies ever approved by the FDA, work in people with certain blood cancers, even patients whose cancers haven’t responded to other treatments.

Called CAR-T cell immunotherapy (for chimeric antigen receptor T cell), one is for kids and young adults with B cell acute lymphoblastic leukemia, or ALL, approved in August (SN Online: 8/30/17). The other is for adults with non-Hodgkin lymphoma, approved in October. Other CAR-T cell therapies are in testing, including a treatment for multiple myeloma.
“It’s a completely different way of treating cancer,” says pediatric oncologist Stephan Grupp, who directs the Cancer Immunotherapy Program at the Children’s Hospital of Philadelphia. Grupp spearheaded the clinical trials of the newly approved ALL therapy, called Kymriah.

Researchers are developing many different versions of CAR-T cell therapies, but the basic premise is the same: Doctors remove a patient’s T cells (immune system cells that attack invaders) from a blood sample and genetically modify them to produce artificial proteins on their surfaces. Those proteins, called chimeric antigen receptors, recognize the cancer cells in the patient’s body. After the modified T cells make many copies of themselves in the lab, they’re unleashed in the patient’s bloodstream to find and kill cancer cells.
CAR-T cell therapy is particularly exciting because it works well in people whose cancers haven’t responded to other available treatments, says Renier Brentjens, an oncologist at Memorial Sloan Kettering Cancer Center in New York City. Of the 63 kids and young adults treated in a clinical trial of Kymriah, 83 percent had their cancers go into remission within three months.
Now that these therapies have been clinically approved, there’s been an “explosion of interest” in the approach, says Dario Campano, an immunopathologist at the National University Cancer Institute in Singapore. Going forward, he expects to see even more rapid progress in the technology. Fifteen years ago, Campana helped develop the chimeric antigen receptor that’s used in Kymriah today. For now, the treatments are approved for use only when other treatments have failed, but someday CAR-T cell therapy could be the first treatment doctors try, he says.

One drawback is the price. Kymriah costs $475,000 for a onetime treatment, according to Novartis, which makes Kymriah. The non-Hodgkin lymphoma treatment made by Gilead Sciences, called Yescarta, is listed at $373,000. The total price tag for treatment could be higher when the costs of dealing with side effects and complications are factored in.

The approach is approved only for blood cancers. Using CAR-T cell therapy on solid tumors will require finding ways to get the T cells past additional cellular roadblocks, Grupp says.

Have you fallen behind on your reading this year? Or maybe you’ve plowed through your must-reads and are ready for more. Science News has got you covered. Here are the staff’s picks for some of the best science books of 2017. Find detailed reviews from previous issues in the links below or in our Editors pick: Favorite books of 2017.

Against the Grain
James C. Scott

Armed with the latest archaeological research, a political anthropologist argues that the rise of civilization came at a big cost. The initial switch from hunting and gathering to agricultural states brought poor diets, labor-intensive work, outbreaks of infectious diseases and other hardships (SN: 10/14/17, p. 28). Yale Univ., $26

The Great Quake
Henry Fountain

Historical records and interviews with survivors flesh out this tale of how a massive earthquake in Alaska in 1964 provided geologists with key evidence needed to verify the theory of plate tectonics (SN: 9/16/17, p. 32). Crown, $28

Eclipse
Frank Close

More than just a primer on the science of solar eclipses, this memoir chronicles a physicist’s lifetime fascination with the celestial phenomenon and introduces readers to the quirky world of eclipse chasers (SN: 5/13/17, p. 28). Oxford Univ., $21.95

Rise of the Necrofauna
Britt Wray

Resurrecting woolly mammoths, passenger pigeons and other extinct creatures isn’t just a technological problem, as this book explains. “De-extinction” is also rife with ethical dilemmas (SN: 10/28/17, p. 28). Greystone Books, $26.95

Big Chicken
Maryn McKenna

Antibiotics transformed chicken farming, to the detriment of the birds and of human health, a journalist contends. Widespread use of the drugs fueled the industrialization of poultry production and the rise of antibiotic-resistant bacteria (SN: 9/30/17, p. 30). National Geographic, $27

Inferior
Angela Saini

A science writer makes a persuasive case that centuries of biased thinking and flawed scientific research have reinforced sexist stereotypes about women (SN: 9/2/17, p. 27). Beacon Press, $25.95

Caesar’s Last Breath
Sam Kean

Through fun historical anecdotes and lesser-known backstories of scientific greats, this entertaining book profiles the chemical elements that make up the air we breathe and traces the history of Earth’s atmosphere (SN: 7/8/17 & 7/22/17, p. 38). Little, Brown and Co., $28

Cannibalism
Bill Schutt

The grisly practice of eating your own kind turns out to be widespread in the animal kingdom, a zoologist explains in this captivating look at cannibalism (SN: 2/18/17, p. 29). Algonquin Books, $26.95

The Lost City of the Monkey God
Douglas Preston

A journalist tags along on an archaeological expedition to search for the real-life remains of a mythological city in this rainforest adventure tale that morphs into a medical mystery (SN: 2/4/17, p. 28). Grand Central Publishing, $28

The Death and Life of the Great Lakes
Dan Egan

Invasive species, urbanization and other threats have wreaked havoc on the Great Lakes, but this book still finds some glimmers of hope in the scientists who are making headway in resuscitating the ecosystem (SN: 3/18/17, p. 30). W.W. Norton & Co., $27.95

How to Tame a Fox
Lee Alan Dugatkin and Lyudmila Trut

An experiment to replay animal domestication by selectively breeding wild silver foxes is lovingly retold, including by the researcher who has kept the project alive for nearly 60 years (SN: 5/13/17, p. 29). Univ. of Chicago, $26

Making Contact
Sarah Scoles

In the face of numerous obstacles, Jill Tarter still managed to spearhead the search for extraterrestrial intelligence for decades, as this biography recounts (SN: 8/5/17, p. 26). Pegasus Books, $27.95

A Crack in Creation
Jennifer A. Doudna and Samuel H. Sternberg

Two experts, including one of the pioneers of CRISPR/Cas9, discuss the science and ethics of gene editing. Houghton Mifflin Harcourt, $28

These book reviews contain links to Amazon.com. Science News is a participant in the Amazon Services LLC Associates Program. Please see our FAQ for more details.

Life expectancy in the United States has decreased for the second year in a row, the first back-to-back drops in more than 50 years, the U.S. Centers for Disease Control and Prevention reports.

In 2016, life expectancy at birth was 78.6 years for the U.S. population as a whole. That’s 0.1 year less than in 2015. For men, life expectancy decreased from 76.3 years in 2015 to 76.1 years in 2016, while in women it remained the same, at 81.1 years. The new data, from CDC’s National Center for Health Statistics, are published online December 21.
Heart disease was the leading cause of death for 2016, followed by cancer, unintentional injuries such as drug overdoses and car crashes, chronic lower respiratory diseases including asthma, and stroke. Rounding out the top 10 causes of death were Alzheimer’s disease, diabetes, influenza and pneumonia, kidney disease and suicide.

The overall drop in life expectancy is largely a result of an uptick in the age-adjusted death rates for unintentional injuries, Alzheimer’s disease and suicide, the report’s authors say.

The driving force behind Yellowstone’s long and explosive volcanic history may not be as deep as once thought. A new study suggests that instead of a plume of hot mantle that extends down to Earth’s core, the real culprit is a subducting tectonic plate that began sinking beneath North America hundreds of millions of years ago.

Computer simulations show that movement of broken-up remnants of the ancient Farallon Plate could be stirring the mantle in a way that fuels Yellowstone, researchers report December 18 in Nature Geoscience. “The fit is so good,” says study coauthor Lijun Liu, a geodynamicist at the University of Illinois at Urbana-Champaign.
The giant supervolcano now beneath Yellowstone National Park, located mostly in Wyoming, has a 17-million-year history — much of it on the move. In that time, the locus of volcanism has moved northeastward from southwestern Idaho to its current location, where it most recently explosively erupted about 640,000 years ago. These shifting eruptions have created a track of volcanic craters resembling those created by the hot spot that formed the Hawaiian island chain. As a result, scientists have long suspected that a deep plume of magma originating from the core-mantle boundary, similar to the one that fuels Hawaii’s volcanoes, is the source of Yellowstone’s fury.

But the nature of the Yellowstone plume has been the subject of debate. “Usually with plumes, we can trace them to the core-mantle boundary,” says Robert Porritt, a seismologist at the University of Texas at Austin, who was not involved in the new work. To “see” Earth’s structure, seismologists use a technique called seismic tomography, which maps the interior using seismic waves generated by earthquakes. Particularly hot or liquid parts of the mantle slow some seismic waves known as shear waves. Tomographic images of mantle plumes such as the one beneath Hawaii show a low-velocity region that extends all the way down to the boundary between mantle and core, about 2,900 kilometers below Earth’s surface. Such deep plumes are thought to be necessary to provide sufficient heat for the volcanism.

“But at Yellowstone, we don’t have that large low-shear velocity thing at the core-mantle boundary,” Porritt says. Current images suggest a region of low-velocity material extending at least 1,000 kilometers deep — but whether there is a deeper plume is uncertain.

And the region is tectonically complex. About 200 million years ago, a tectonic plate to the west, known as the Farallon Plate, began to slide eastward beneath the North American Plate. The current Juan de Fuca Plate off the Pacific Northwest coast, one of the last remnants of the Farallon Plate, continues to slide beneath the western United States. Some researchers have suggested that, instead of a deep mantle plume, the flexing and melting of the subducting Juan de Fuca Plate are responsible for Yellowstone’s volcanism.
Liu and his colleagues have yet another idea. In 2016, Liu published research suggesting that the sinking ancient Farallon slab was acting like a lid on a deep mantle plume, preventing the plume from rising to the surface (SN Online: 2/3/16). “But we kept in mind that the problem was not solved,” Liu says. “The heat source [for Yellowstone] was still missing.”

The researchers created a sophisticated, supercomputer-driven series of simulations to try to find the best scenario that matches the three known knowns: the current tomographic images of the subsurface beneath the western United States; the volcanic history at Yellowstone as well as in the nearby Basin and Range regions; and the movements of the subducting slab since about 20 million years ago.

Yellowstone’s volcanism is linked not just to the currently subducting young Juan de Fuca Plate, but also to the remnants of its older incarnation, the Farallon Plate, the simulations suggest. Those remnants have continued to slide deeper and now lie beneath the eastern United States. This downward dive dragged hot mantle eastward along with it. As the Juan de Fuca Plate began to break up beneath the western United States, the hot mantle rose through the cracks. Some of that hot mantle circulated back to the west across the top of the Juan de Fuca Plate, fueling volcanism in the Basin and Range region. And some of it flowed eastward, adding heat to Yellowstone’s fire. The study doesn’t rule out the presence of a deep magma plume, but it suggests that such a plume plays little role in Yellowstone’s volcanism.

Porritt says he’s intrigued by the idea that the sinking Farallon slab beneath the central and eastern United States could be driving mantle circulation on such a large scale. However, he says, he isn’t convinced that the authors have truly solved the larger mystery of Yellowstone’s volcanism — or that a yet-to-be-found deep plume still isn’t playing a major role. “It’s an interesting debate that’s going to be raging, hopefully for decades.”

Fracking wells should not go to 11. Instead, turning down the volume — that is, of water pumped underground to help retrieve oil and gas — may reduce the number of earthquakes related to hydraulic fracturing.

The amount of water pumped into fracking wells is the No. 1 factor related to earthquake occurrence at Fox Creek, a large oil and gas production site in central Canada, researchers report January 19 in Science. An injection of 10,000 cubic meters of fluid or more at a well appears to trigger a quake.
Fox Creek sits atop the Duvernay Formation, a sedimentary layer rich in oil and gas. Before December 2013, the area was earthquake-free. Since then, hundreds of earthquakes have shaken the region; most were below magnitude 4, but a magnitude 4.8 quake in 2016 temporarily shut down operations.

Previous investigations revealed that fracking well injections at the site were triggering earthquakes on an underlying fault system. But mysteries remained: For example, why didn’t the quakes didn’t start until almost three years after fracking activities began in 2010?

Ryan Schultz of the Alberta Geological Survey in Edmonton and his colleagues compared the timing and location of the earthquakes with fracking activity at 300 wells in the region.

An analysis of rates of injection, fluid pressure and fluid volume for the wells closest in proximity to the quakes revealed that, at this site, only volume was linked to the quakes. A previous study has linked the rate of wastewater disposal injections to seismic slip (SN: 7/11/15, p. 10).
As for the three-year delay, the authors say, fracking well injections tend to increase in volume over time as operations mature. So once the injection volumes reached that 10,000-cubic- meter threshold, the earthquakes began.