Manchester, England, is not the birthplace of graphene — the atom-thin, honeycomb-like layer of carbon known for its wondrous properties and seemingly limitless applications. But the city is the material’s main booster and, according to the University of Manchester, the official Home of Graphene. That’s because it was there that Andre Geim and Kostya Novoselov figured out that you could isolate the elusive material from graphite (the “lead” in pencils) with repeated dabs of sticky tape.
The two-dimensional material also proved to be a peerless electrical conductor and superstrong, earning the two Manchester scientists the 2010 Nobel Prize in physics. So when the city played host to the EuroScience Open Forum conference late last month, it made sense that Geim, graphene and the material’s many evolving applications took center stage. At the local science museum’s new exhibit about graphene, I learned that Geim is the only Nobelist who has also been honored with an Ig Nobel (which has fun celebrating seemingly useless research in science). He contends many are more familiar with his Ig Nobel–winning device to levitate a tiny frog than with his work on graphene.

Notably, graphene comes up in both of the feature stories in this issue, adding some heft, perhaps, to Mancunian claims. In Thomas Sumner’s cover story “Quenching society’s thirst,” about the growing interest in desalination to meet the globe’s escalating need for freshwater, graphene oxide has a potentially starring role. New membranes made from this material may help increase the efficiency of separating salt from water. Cost and efficiency, Sumner reports, remain the biggest obstacles to the widespread use of desalination.

Graphene can serve as analogy and inspiration in physicists’ efforts to create solid metallic hydrogen, another theorized wonder material, which Emily Conover describes in “Chasing a devious metal.” “It’s a high-stakes, high-passion pursuit that sparks dreams of a coveted new material that could unlock enormous technological advances in electronics,” Conover writes. Solid hydrogen, which has been made, takes on a graphenelike structure when squeezed to high pressures. Solid metal hydrogen might be a superconductor at room temperature, an exciting prospect. Despite significant progress, so far no one has been able to create it.

Local celebrity or not, graphene did share the spotlight with other science superstars at the EuroScience meeting. The gene-editing tool CRISPR got lots of attention. In a review of the historic detection of gravitational waves, Sheila Rowan of the University of Glasgow offered a bevy of questions that gravitational astronomy might be able to answer in the coming years: Where and when do black holes form? What does that tell you about the large-scale formation of galaxies? Is general relativity still valid when gravity is very strong (such as near supermassive black holes)? A session on the human microbiome generated even more questions, as scientists described efforts to use microbial species as telltale signs of diseases such as cancer. And a debate about how to prevent food allergies left most agreeing that more data are needed. As answers come in on all of these and many more fascinating topics, you can be sure that Science News will be there to report on them.

COLUMBIA, Mo. — Human babies born via cesarean section miss out on an opportunity to pick up beneficial microbes that other babies get when they take a trip through mom’s vagina. And even though the scientific jury’s still out on whether this is a good idea, some parents have been wiping their C-section babies down with vaginal fluid in the hopes that their newborns might get some of those microbial benefits, Laura Sanders reported earlier this yearover at the Growth Curve blog.

Microbial transfer from mom to offspring happens in a lot of species, but researchers are more familiar with how species that give live birth do this than those that lay eggs, biologist Stacey Weiss of the University of Puget Sound in Tacoma, Wash., noted August 1 at the 53rd Annual Conference of the Animal Behavior Society. Researchers have found that moms can transfer microbes right into the egg itself before it is laid or onto or near the egg after laying.

But Weiss thinks that such microbial transfer might happen through another route — as eggs travel through a female animal’s cloaca. (The cloaca is a combination of genital tract and end of the digestive system found in many invertebrates and most vertebrates, except most mammals.) She and her colleagues have been studying whether striped plateau lizard moms transfer microbes that protect their eggs from pathogens.

“Pathogenic infection is one of the leading causes of egg mortality,” she said. And some studies have proposed that microbes might be able to protect against those infections. None have yet proposed that the source of the microbes could be the cloaca, but this might be a common source since “all vertebrate eggs go through cloacas, and all cloacas have microbes,” she said.

Weiss latched onto the idea that microbes from the cloaca might be important after noticing that when she obtained eggs through dissection, they tended to have a lower survival rate than eggs that were laid. The dissected eggs often succumbed to fungal infections, while the laid eggs did not.

She and her team started by comparing the microbiomes of male and female lizards’ cloacas. “Females are different than males,” she said. Males had more diverse microbial communities in their cloacas. Females were missing whole categories of microbes found in males and had one type that is known to have antifungal activity.

The researchers then compared the microbiomes of eggs that were laid with those that had been dissected out. The team is still waiting on the results of DNA tests that will tell them exactly what kinds of microbes are found on the eggs, but initial results showed that the laid eggs are more likely to have any bacteria at all. “There’s something about going through the cloaca that is increasing bacterial load on these eggshells,” Weiss said. Fungi, though, showed up only on eggs that had been obtained through dissection.
Weiss, her colleagues and some high school students then performed tests in which fungus was applied directly to eggs. They found that laid eggs were able to inhibit fungal growth while dissected eggs were not. So it appears that the mom’s cloaca microbiome may indeed be providing some protection for her offspring.

Weiss said that these results, while still preliminary, may help expand what parental protection of offspring means. In species without direct parental care, transfer of microbes might be an important way that moms and dads help to keep their offspring safe.

Going for walks, playing fetch and now participating in genetic research are just a few things people and their dogs can do together.

Darwin’s Dogs, a citizen science project headquartered at the University of Massachusetts Medical School in Worcester, is looking for good — and bad — dogs to donate DNA. The project aims to uncover genes that govern behavior, including those involved in mental illness in both people and pets.

Looking to dogs for clues about mental illness isn’t as strange as it may seem. Certain breeds are plagued by some of the same diseases and mental health issues that afflict people. Researchers have learned about the genetics of narcolepsy and obsessive compulsive disorder, as well as cancer, blindness and many other ailments from studying purebred dogs. Studies of purebreds are mainly useful when the problem is caused by mutations in a single gene. But most behaviors are the product of interactions between many genes and the environment. A search for those genes can’t be done with a small number of genetically similar dogs. So, Darwin’s Dogs hopes to gather data on a large number of canines, including many breeds and genetically diverse mutts.
Finding behavior-related genes, such as ones that lead dogs to chew up shoes or engage in marathon fetch sessions, may give clues to genes that affect human behavior. “It seemed to me that if we could understand how [changes in DNA] make a dog so excited about chasing a ball, we could learn something about how our brains work and what goes wrong in psychiatric disease,” says project leader Elinor Karlsson.

Karlsson and colleagues launched darwinsdogs.org, inviting people to answer questions about their dogs’ behavior and share their pets’ DNA. More than 7,000 dog owners have already signed up, and the researchers are still recruiting new volunteers.

The process is simple and can be done alone with your dog, or even as a family activity. First, take an online quiz about your canine companion. The quiz is divided into multiple sections. Some sections gather basic information about your dog’s appearance, exercise and eating habits; others ask about simple behaviors, such as whether your dog crosses its front paws when lying down or tilts its head. (Some questions are philosophical puzzles like whether your dog knows it is a dog.) Each question has a comment box in case you want to explain an answer. Plan to spend at least half an hour completing the questionnaire.

Once the questions are answered and the dog is registered, researchers send you a DNA sampling kit that comes with written instructions and an easy-to-follow picture guide. The kit contains a large sterile cotton swab for collecting DNA from your dog’s mouth. (It’s an easy procedure for the human involved, and Sally, the 14-year-old Irish setter “volunteer” Science News sampled, was rather stoic.) Also included is a tape measure for recording your dog’s height, length, nose and collar size. When you’re done, just seal the sample, measurement sheet and consent form inside the return mailer and drop it in a mailbox.

Dog owners don’t need to pay a fee to participate, but they do need patience, Karlsson says. It takes time to analyze DNA, and the researchers can’t say exactly how long it will be before owners (and Science News) learn their dogs’ results. These results will include the dog’s raw genetic data as well as information about the dog’s possible ancestry. Knowing ancestry or particular mutations a dog carries may help veterinarians personalize a dog’s care.
Dog trainers are being enlisted to give owners feedback on their dogs’ personalities and to suggest activities the dogs may enjoy. Karlsson hopes to create a way for impatient owners who are willing to donate money to the project to get their reports back faster.

If you’d like to vacation at the newly found planet orbiting Proxima Centauri, you might want to reconsider. It’s nearby astronomically — a mere 4.2 light-years away — but still too far away for any plausible transportation technology to reach within the current millennium.

In fact, it’s a pretty safe bet the Chicago Cubs will win the World Series before any human steps foot on Earth’s nearest exoplanetary neighbor (known as Proxima b). Unless P. Centaurian aliens arrive soon with a “To Serve Man” cookbook, your chances of visiting Proxima b before you die are about the same as sainthood for Ted Bundy. By the time anybody from here goes there, years will have five digits.

It took NASA’s New Horizons probe — the fastest spacecraft humans have ever launched — over nine years just to get to Pluto. At its top speed of 16 kilometers per second, New Horizons would need almost 80,000 years to get to Proxima Centauri.

Solar sail propulsion — in which lightweight craft could be accelerated by pressure from sunlight — would be a little be faster, but not by much, taking (by one estimate) 66,000 years to make the Proxima Centauri run.

Novel propulsion schemes have been proposed that could reduce that time substantially. A sail driven by alpha particle recoil, for instance, provides some serious advantages over solar sails, as Wenwu Zhang and colleagues point out in the August issue of Applied Radiation and Isotopes.

Ordinary rocket speed is limited by how fast the combusted fuel can eject exhaust; NASA has investigated a plasma engine design that can attain exhaust speeds of 50 km/s. But that approach requires huge energy input and high voltage, Zhang and colleagues point out (and so would be prohibitively expensive). Alpha particles emitted by radioactive substances, on the other hand, can speed away about 300 times faster. Therefore, Zhang and coauthors assert, “alpha decay particles … may be a potential solution for long-time acceleration in space.”

Usually, of course, a chunk of radioactive matter would emit alpha particles in all directions. So your craft would need a shield on one side to absorb the particles before they got very far. The rest would stream away in the opposite direction, pushing the craft forward (by virtue of the law of conservation of momentum). True, alpha particles are tiny and the effect of their recoil would be small. But it would add up. Shot into space with standard technology (thereby achieving a 16 km/s start-up speed), an alpha recoil spacecraft could eventually reach a speed in the range of 200–300 km/s or so.
It helps to choose the right alpha-emitting material. Uranium-232 would be ideal. It has a long enough half-life (almost 70 years) to last for an extended voyage, but it also decays into daughter nuclei that emit alpha particles more frequently, boosting the recoil effect. (You won’t find any U-232 in uranium mines, though — it would need to be produced in nuclear transmutation factories.)

Assuming a suitably light and thin absorption material, Zhang and colleagues envision an alpha-powered interstellar sail about 24 meters across. They calculate a travel time to Proxima Centauri between about 4,000 and 9,000 years (depending on the ratio of fuel mass to total spacecraft mass). That would easily win the race against a solar sail, but would far exceed most people’s available vacation time. “Interstellar travel definitely asks for even better propulsion technologies,” Zhang and colleagues understate. And surely within 4,000 years somebody will invent a faster technology that could pass the alpha-decay craft and get to Proxima b first.

Other people already have ideas, as Science News astronomy writer Christopher Crockett noted in his story on the discovery of Proxima b. Philanthropist Yuri Milner recently announced a research project to explore the prospects of sending numerous nanocraft to Proxima Centauri’s neighborhood — the Alpha Centauri triple star system. (Proxima is the third star, presumably in orbit around Alpha Centauri A and B.) That plan envisions wafers weighing about a gram or so carried along by similar-mass light sails propelled by a powerful laser beam. If current technological dreams come true, tiny cameras and lasers on the wafer could capture and transmit information about Proxima b back to Earth.

Supposedly such nanocraft could reach 20 percent of the speed of light, allowing them to reach Proxima Centauri by maybe 20 years after launch. So there’s an outside chance of getting a message back from Proxima b before the Cubs win a World Series. But there’s no hope of hitching a ride on such a wafer, unless, perhaps, you’re a tardigrade.

Even if some futuristic technology permitted building a real ship, say the size of the space shuttle, that could fly 20 percent of the speed of light, it might not be a good idea. Such a ship could, in the wrong hands, become the most devastating weapon ever imagined. Flying 20 percent of light speed, a space shuttle would possess a kinetic energy roughly the equivalent of 1,000 hydrogen bombs (or millions of Hiroshima-sized bombs). Of course, it would be an expensive ship and probably nobody would want to crash it. Unless the people who took it to Proxima Centauri got really mad at the people back on Earth.

As of today, antibacterial soaps have a short shelf life. The U.S. Food and Drug Administration has banned soap products containing 19 active ingredients, including the notorious chemical triclosan, marketed as antiseptics.

While the term “antibacterial” suggests to consumers that such soaps prevent the spread of germs, evidence suggests otherwise. After asking companies to submit data on the safety and efficacy of their products back in 2013, the FDA noted in its September 2 final ruling that manufacturers failed to prove that these products were safe to use every day or that they were more effective than plain old soap and water at cutting infectious microbes.

“In fact, some data suggests that antibacterial ingredients may do more harm than good over the long-term,” Janet Woodcock, director of the FDA’s Center for Drug Evaluation and Research, said in a statement.

Triclosan, in particular, has a pretty bad rap. Found in many household products, the chemical ends up everywhere from vegetables to our snot. It’s been associated with exposure to toxic compounds, risk of staph infections and mucking up sewage treatment. Over a decade of damning data had already prompted some companies to remove triclosan from their products. Others will have a year to remove it and other newly banned ingredients from their recipes.

The FDA ban does not include antibacterial hand sanitizers, which the agency is evaluating separately. In the meantime, the FDA recommends using hand sanitizers that are at least 60 percent alcohol, or washing with old-school soap and water.

Live long and prosper
In Science News’ special report on a­ging (SN: 7/23/16, p. 16), writers Laura Sanders, Tina Hesman Saey and Susan Milius explored the latest research — from the evolution of aging in the animal kingdom to scientists’ quest to delay the process in humans’ bodies and minds.

“I would very much like to know how research into aging may benefit people who are middle-aged or elderly now?” asked leftysrule200 in a Reddit Ask Me Anything about the special report. “Is there any research that can result in treatments in the very near future, or are the real-world applications only going to be visible in the distant future?”
Middle-aged and elderly people will be the first to benefit from aging research, Saey says. “A clinical trial using the diabetes drug metformin as an antiaging therapy will begin soon. That drug will be tested on healthy people aged 60 and older,” she says.

Sanders cautions that most antiaging treatments are still a long way off. But various studies in rodents and humans provide potential clues to aging’s secrets. Blood from young rats, for instance, has been shown to rejuvenate the bodies and brains of old rats. Based on those findings, a clinical study in humans is now under way that is looking at the effects of plasma from young donors on the brains of people with Alzheimer’s. “If scientists could pinpoint the compounds that give young blood its power, then they could presumably develop drugs that mimic that process,” Sanders says.
In the meantime, people may be able to slow the effects of aging by leading a healthy lifestyle. Sanders points to a long-term study of middle-aged women in Australia. Women who were more physically active had sharper memories 20 years later, the researchers found. Until proven antiaging treatments are available, “it seems that keeping the body physically active and strong is one of the best ways to keep your brain sharp as you age,” she says.
Dino spills its guts
Tiny tracks discovered in the blackened stomach contents of a 77-million-year-old duck-billed dinosaur fossil suggest gut parasites infected dinosaurs, Meghan Rosen reported in “Parasites wormed way into dino’s gut” (SN: 7/23/16, p. 14).

Online reader Jim Stangle Dvm thought the worms may not have been parasites at all. “It is more likely that the tunnels were formed by a scavenger worm [after the dino had died]. Still I think the findings are way cool!” he wrote.

It’s hard to say definitively whether the burrows were made by parasites or not, says paleontologist Justin Tweet. Scavenger worms could have tunneled through the gut after the dino’s death, but his team found only one type of worm burrow “which suggests that either only one kind of scavenger had access to the carcass,” or “that these burrows were an inside job,” Tweet says.

That’s no moon!
A recently discovered asteroid appears to orbit Earth, but that’s just an illusion. The asteroid orbits the sun, but its constant proximity to Earth makes it the planet’s only known quasisatellite, Christopher Crockett reported in “Say What? Quasi­satellite” (SN: 7/23/16, p. 5).

Reader Mike Lieber wondered if the moon could also be a quasisatellite. “The gravitational attraction of the sun on the moon is twice that of the Earth,” he wrote. “It seems that the apparent looping of the moon around the Earth is also illusory.”

The moon is a true satellite, Crockett says. If the sun were to dis­appear, the moon would continue orbiting Earth. “The moon is within Earth’s ‘Hill sphere,’ the volume of space in which Earth’s gravity is the dominant influence,” he says. “The strength of the gravitational force isn’t as important as by how much it changes from one place to another.” Given the moon’s proximity to our planet, Earth prevails. “The moon orbits Earth and the Earth-moon s­ystem orbits the sun,” he says.

Modern rattlesnakes have pared down their weaponry stockpile from their ancestor’s massive arsenal. Today’s rattlers have irreversibly lost entire toxin-producing genes over the course of evolution, narrowing the range of toxins in their venom, scientists report September 15 in Current Biology.

“After going through all the work of evolving powerful toxins, over time, some snakes have dispensed with them,” says study coauthor Sean B. Carroll, an investigator with the Howard Hughes Medical Institute who is at the University of Wisconsin–Madison. These modern rattlesnakes produce smaller sets of toxins that might be more specialized to their prey.
Carroll, an evolutionary biologist, and his colleagues focused on a family of enzymes called phospholipase A2, or PLA2. Genes in the PLA2 family are one of the main sources of toxic proteins in the deadly cocktail of rattlesnake venom. This set of genes can be shuffled around, added to and deleted from to yield different collections of toxins.

Data from the genome — the complete catalog of an organism’s genetic material — can reveal how those genetic gymnastics have played out over time. Carroll’s team looked at the relevant genome regions in three modern rattlesnake species (western diamondback, eastern diamondback and Mojave) and also measured molecules that help turn genetic instructions into proteins. That showed not just how the genes were arranged, but which genes the snakes were actually using. Then, the scientists blended that data with genetic information about other closely related rattlesnakes to construct a potential evolutionary story for the loss of PLA2 genes in one group of snakes.

The most recent common ancestor of this group probably had a large suite of PLA2 genes 22 million years ago, the scientists found. That collection of genes, which probably came about through many gene duplications, coded for toxins affecting the brain, blood and muscles of the snake’s prey. But 4 million to 7 million years ago, some rattlesnake species independently dropped different combinations of those genes to get smaller and more specialized sets of venom toxins. For instance, three closely related rattlesnake species in the group lost the genes that made their venom neurotoxic.

“The surprise is [the genes’] wholesale loss at two levels: complete disappearance from the venom and complete disappearance from the genome,” Carroll says. In other words, some of the genes are still lurking in the genome but aren’t turned on. The proteins those genes produce don’t show up in the venom in modern snakes. But other genes have left the genome entirely — a more dramatic strategy than simple changes in gene regulation.

Environmental shifts might have encouraged this offloading of evolutionary baggage, Carroll says. If a certain snake species’ main food source stopped responding to a neurotoxin, the snake would waste energy producing a protein that didn’t do anything helpful.
Plus, a rattlesnake doesn’t just invest in producing venom. It also needs to produce antibodies and other proteins to protect itself from its own poison, says Todd Castoe, an evolutionary biologist at the University of Texas at Arlington who wasn’t involved in the study. As a snake’s weapon becomes more complex, its shield does too — and that protection can use up resources.

Researchers also found that venom genes might not be consistent even within a single species of rattlesnake, perhaps because snakes in different areas specialize in different prey. One western diamondback rattlesnake that Carroll’s team sampled had unexpected extra genes that the other western diamondbacks didn’t have. His lab is currently looking into these within-species differences in venom composition to see how dynamic the PLA2 genome region still is today.

As for the ancestral rattlesnake, it’s impossible to say exactly how powerful the now-extinct reptile’s venom was, Carroll says. But the wider variety of enzymes this rattlesnake could hypothetically produce would have given it more flexibility to adapt its poison to environmental curveballs — an ability that Castoe describes as “the pinnacle of nastiness.”

Your summer suntan is almost entirely locally sourced. But a smidgen of that healthy glow hails not from the sun but from the ultraviolet light of nearby stars and other galaxies: less than one-billionth of 1 percent. Even photons lingering from the Big Bang contribute some: roughly 0.001 percent.

Simon Driver, an astronomer at the University of Western Australia in Crawley, and colleagues calculated these numbers, but not because they’re interested in tanning. They were trying to decipher the extragalactic background light, or EBL, a diffuse glow that fills the universe (SN: 9/7/13, p. 22). Using galaxy observations from multiple telescopes, they assessed the number of EBL photons, from infrared to ultraviolet, that reach Earth. About half originated with the formation of galaxy cores and supermassive black holes during roughly the first 4 billion years of cosmic history, the researchers report in the Aug. 20 Astrophysical Journal. The growth of disks of stars in galaxies since that time accounts for the other half.

For some dropped foods, the five-second rule is about five seconds too long. Wet foods, such as watermelon, slurp up floor germs almost immediately, scientists report online September 2 in Applied and Environmental Microbiology.

Robyn Miranda and Donald Schaffner of Rutgers University in New Brunswick, N.J., tested gummy candy, watermelon and buttered and unbuttered bread by dropping morsels onto various surfaces coated with Enterobacter aerogenes bacteria. Food was left on each surface — stainless steel, ceramic tile, wood and carpet — for time periods ranging from less than a second to five minutes. Afterward, the researchers measured the amount of E. aerogenes on the food, harmless bacteria that share attachment characteristics with stomach-turning Salmonella.

As expected, longer contact times generally meant more bacteria on the food. But the transfer depended on other factors, too. Carpet, for instance, was less likely to transfer germs than the other surfaces. Gummy candies, particularly those on carpet, stayed relatively clean. But juicy watermelon quickly picked up lots of bacteria from all surfaces in less than a second. These complexities, the authors write, mean that the five-second rule is probably a rule worth dropping.

Shock waves may have jolted the infant cosmos. Clumpiness in the density of the early universe piled up into traveling waves of abrupt density spikes, or shocks, like those that create a sonic boom, scientists say.

Although a subtle effect, the shock waves could help scientists explain how matter came to dominate antimatter in the universe. They also could reveal the origins of the magnetic fields that pervade the cosmos. One day, traces of these shocks, in the form of gravitational waves, may even be detectable.
Scientists believe that the early universe was lumpy — with some parts denser than others. These density ripples, known as perturbations, serve as the seeds of stars and galaxies. Now, scientists have added a new wrinkle to this picture. As the ripples rapidly evolved they became steeper, like waves swelling near the shore, until eventually creating shocks analogous to a breaking wave. As a shock passes through a region of the universe, the density changes abruptly, before settling back down to a more typical, slowly varying density. “Under the simplest and most conservative assumptions about the nature of the universe coming out of the Big Bang, these shocks would inevitably form,” says cosmologist Neil Turok of the Perimeter Institute for Theoretical Physics in Waterloo, Canada.

In a paper published September 21 in Physical Review Letters, Turok and Ue-Li Pen of the Canadian Institute for Theoretical Astrophysics in Toronto performed calculations and simulations that indicate shocks would form less than one ten-thousandth of a second after the Big Bang.

“It’s interesting that nobody’s actually noticed that before,” says cosmologist Kevork Abazajian of the University of California, Irvine. “It’s an important effect if it actually happened.”

These shocks, Turok and Pen found, could produce magnetic fields, potentially pointing to an answer to a cosmological puzzle. Magnetic fields permeate the Milky Way and other parts of the cosmos, but scientists don’t know whether they sprang up just after the birth of the universe or much later, after galaxies had formed. Shock waves could explain how fields might have formed early on. When two shocks collide, they create a swirling motion, sending electrically charged particles spiraling in a way that could generate magnetic fields.
Shocks could also play a role in explaining why the universe is made predominantly of matter. The Big Bang should have yielded equal amounts of matter and antimatter; how the cosmic scales were tipped in matter’s favor is still unexplained. Certain theorized processes could favor the production of matter, but it’s thought they could happen only if temperatures in the universe are uneven. Shocks would create abrupt temperature jumps that would allow such processes to occur.

Scientists may be able to verify these calculations by detecting the gravitational waves that would have been produced when shocks collided. Unfortunately, the gravitational ripples produced would likely be too small to detect with current technologies. But under certain theories, in which large density fluctuations create regions so dense that they would collapse into black holes, the gravitational waves from shocks would be detectable in the near future. “If there was anything peculiar in the early universe, you would actually be able to detect this with upcoming technology,” says Abazajian. “I think that is remarkable.”