Uranus’ upper clouds are made of hydrogen sulfide — the same molecule that gives rotten eggs their noxious odor.

“At the risk of schoolboy sniggers, if you were there, flying through the clouds of Uranus, yes, you’d get this pungent, rather disastrous smell,” says planetary scientist Leigh Fletcher of the University of Leicester in England.

Using a spectrograph on the Gemini North telescope in Hawaii, Fletcher and his colleagues detected the chemical fingerprint of hydrogen sulfide at the top of the planet’s clouds, the team reports April 23 in Nature Astronomy.

That wasn’t a complete surprise: Observations from the 1990s showed hints of hydrogen sulfide lurking deeper in Uranus’ atmosphere. But the gas hadn’t been conclusively detected before.
The clouds aren’t just smelly — they can help nail down details of the early solar system. Uranus’ hydrogen sulfide clouds set it apart from the gas giant planets, Jupiter and Saturn, whose cloud tops are mostly ammonia.

Hydrogen sulfide freezes at colder temperatures than ammonia. So it’s more likely that frozen hydrogen sulfide ice crystals would have been abundant in the further reaches of the early solar system, where the crystals could have glommed onto newly forming planets. That suggests that ice giants Uranus and Neptune were born farther from the sun than Jupiter and Saturn.

“This tells you the gas giants and the ice giants formed in a slightly different way,” Fletcher says. “They had access to different reservoirs of material back in the forming days of the solar system.”

Fletcher is far from repelled by the malodorous clouds. He and other planetary scientists want to send a spacecraft to the ice giants — the first since the Voyager spacecraft visited in the 1980s — to find out more (SN: 2/20/16, p. 24).

I am not the first person who has considered composing poetry to the placenta. One writer begins: “Oh Lady Placenta! What a life you lived in magenta.” Another almost coos to the “constant companion, womb pillow friend.” It might sound like odd inspiration for verse, but it’s entirely justified.

This vital organ, which is fully formed by about 12 weeks, nurtures a growing fetus throughout pregnancy, offering oxygen, nutrients and antibodies and eliminating waste. The placental cells forge a deep connection between mom and baby, a symbolic early step in a lifelong bond.
Recent research suggests a placenta that works properly might be even more important than previously thought. Myriam Hemberger of the Babraham Institute and the University of Cambridge, along with colleagues in England and Austria, looked at more than 100 genes in mice that are known to be necessary for an embryo to survive. More than two-thirds of those mouse genes were linked to problems with the placenta. And death of the embryo around days 10 to 15 —when, in mice, the placenta takes over from the yolk sac to supply nutrients — was almost always tied to these placental problems.

The study makes you wonder: How many birth defects in humans might have their roots in the placenta? “You cannot just look at the embryo,” says Susan Fisher of the University of California, San Francisco, who studies how placental cells invade the uterus early in pregnancy. “You should work backward from the placenta.”

Both Hemberger and Fisher believe the placenta is underappreciated. I certainly thought much more about my little embryo turned fetus, growing from sesame seed to grape-sized, grapefruit and beyond, than I did about the disk of tissue supporting my baby-to-be. Fisher calls the placenta “the forgotten organ.”

In 2013, Tina Hesman Saey wrote a feature in Science News about new and growing efforts to understand the placenta. The New York Times published a story the following year, headlined “The Mysterious Tree of a Newborn’s Life.”
Then came the launch of the Human Placenta Project, an initiative of the Eunice Kennedy Shriver National Institute of Child Health and Human Development. Since 2015, the project has invested more than $65 million in the development of technologies that can study the placenta in its natural environment, while a woman is pregnant.

“There is a long history of research involving the placenta, for many, many years,” says neonatal geneticist Diana Bianchi, director of the NICHD, who calls the placenta the Rodney Dangerfield of organs. Like the comedian, it gets no respect. “But the research had pretty much exclusively been after delivery.”

Shortly after a baby is born and his umbilical cord is cut, the placenta is expelled from the mother. At that point, it’s straightforward to inspect its size and blood vessels, and to see if scarring or calcium deposits provide clues to poor function. But it’s much too late to predict a fetus in trouble or to intervene in any way that might ultimately protect mom or baby.

Through the Human Placenta Project, researchers are, for example, using ultrasound to investigate placental blood vessels and blood flow in 3-D during the middle trimester and using magnetic resonance imaging to study oxygen distribution in twins who share a placenta but have separate amniotic sacs. How and when such work might make it to the clinic to affect current and future mommies isn’t yet clear.

Bianchi predicts that a deeper appreciation of the role of the placenta, encouraged through Hemberger’s work and similar studies, could change how pregnant women are monitored in the United States. There’s currently very little monitoring for women in the earliest weeks of pregnancy, the window when the placenta is becoming established. Doctor visits then ramp up as the pregnancy progresses. More attention in the first trimester, including attention to the placenta, could identify women who might be at a high risk for stillbirth or premature delivery, even if they are young and healthy by other standards. “That is a very conceivable, no pun intended, but very likely outcome of this research,” Bianchi says.

After identifying so many genes that affect the placenta, Hemberger’s team went on to show that many of those genes are associated in mice with blood vessel, heart and brain problems in a developing fetus. In other words, problems in the heart may have begun elsewhere, in the placenta. Among three of the mouse genes studied in much more detail, the researchers identified one for which the placenta problem was solely responsible for the death of the embryo at around 10 days. Even if the gene was absent from the embryo, restoring it to the placenta could prolong the embryo’s survival.

If the work holds for humans, it might mean that a fix to the placenta could change the course for a dramatic number of babies who would otherwise be born too small or with birth defects. That’s powerful stuff for would-be moms.

And there’s much more work to be done. “You need to understand normal development before you can address anything that goes wrong,” Hemberger says. A lot of pregnancy complications, including those related to the placenta, originate in the first two to eight weeks, which is still “the black box,” she says.

Recent research out of Japan may help. In January, a team there announced deriving and growing human trophoblast stem cells, the cells that form a large part of the placenta. Though such cells have been studied from mice, this could mark the beginning of more fruitful, detailed efforts to understand placenta formation in people. “Approaches like this,” Hemberger says, “can open up what happens in these early stages.”

Once more is known about how it all begins, it may feel perfectly natural for every person born to sing the praises of the placenta, “The tree of life, the mother-child link, Nourishing baby before it can drink.”

Stephen Nicol is here to change your mind about krill: They’re not microscopic and they’re far from boring. The biologist is so sick of people misunderstanding his study subjects that he’s even gotten a (slightly botched) krill tattooed on his arm to help enlighten strangers.

In The Curious Life of Krill, Nicol is taking his mission to an even bigger audience. The book is an ode to Antarctic krill (Euphausia superba), which are among the most abundant animals in the world by mass. Each several centimeters long, krill cloud the ocean in swarms that can span 20 kilometers. They’re a linchpin of ocean ecosystems — a key food source for whales, penguins and other marine life. And yet, Nicol points out, few people would be able to identify these translucent, red-and-green-speckled creatures with feathery appendages.
Anyone who has ever nurtured an affection for a species that others find odd or distasteful or unremarkable will understand Nicol’s devotion. His wry and earnest way of describing krill and their ecology will probably draw in those interested in biology or environmental science.
As one of the world’s leading experts on krill, Nicol offers an insider’s view of the political negotiations over krill fishing in the Southern Ocean. And yet the book’s conversational (sometimes slightly rambling) style makes you feel as if you’re part of an engaging dinnertime conversation. Nicol chronicles the challenges of estimating krill populations and of studying the complex behavior of an animal too small to tag or track. And he shares plenty of delightful anecdotes. At one point, for instance, his lab amassed the world’s largest collection of whale poop to study whether the cetaceans could fertilize the surface ocean by recycling the nutrient iron picked up through the krill they ate. The answer: probably yes.
The book tackles tougher subjects, too. Nicol delves into the threats that Antarctic krill face from fishing — the animals are gathered up for aquaculture feed and also ground into extracts and powders for dietary supplements and medical research — and describes efforts to regulate the industry. He ponders how krill may fare in warming oceans. The critters are resilient, he says, but it’s not clear how quickly these animals, which are known to live as long as about a decade, will adapt to rapidly changing sea temperatures.

Like millions of parents, I post pictures of my kid on Instagram. When she was born, her father and I had a brief conversation about whether it was “dangerous” in a very nebulous sense. Comforted by the fact that I use a fake name on my account, we agreed to not post nudie pics and then didn’t give it much more thought. Until recently.

As she gets older, and privacy on social media dominates the news, I’m revisiting this conversation. Am I invading my daughter’s privacy by sharing her kooky dance moves or epic Nick Nolte hair? Will she feel violated when she’s older? My generation had to contend with mom showing an embarrassing baby photo to our prom date. Is an awkward Instagram picture just today’s equivalent, or does the fact that that the photo can be revisited again and again, by potentially hundreds or even millions of eyes, change things?
There’s a growing amount of scholarship on this issue and the results are somewhat comforting: Most kids aren’t opposed to parents sharing pictures of them, but like most human beings, they would like their feelings to be considered. “Ask your kids’ permission, at least sometimes,” says Sarita Schoenebeck, an expert on how families use technology at the University of Michigan in Ann Arbor. “Pay attention to what they do and don’t like and respect that.”

Schoenebeck and her colleagues recently surveyed 331 parent-child pairs to examine both parents’ and children’s preferences about what’s fair game to share on social media. Overall, the kids, who ranged in age from 10 to 17, didn’t mind when parents posted “positive” content, Schoenebeck’s team reported. Kid-approved posts included pictures showing them engaged in hobbies like sports, or depicting a happy family moment. Embarrassing pictures, on the other hand, were not appreciated. (No “naked butt baby pictures,” said one kid). The team reported its findings in 2017 at the Association for Computing Machinery’s Conference on Human Factors in Computing Systems in Denver.

Kids also expressed being aware of their own privacy in ways adults often don’t give them credit for. Photos with potential boyfriends or girlfriends were not acceptable. Content deemed too candid (such as “what they are really like at home” and “private stuff”) was also off-limits.

This self-awareness was reassuring to me. Much of being a kid is playing literal and figurative dress-up; it’s figuring out what’s OK and not OK, personally, as a family member and as a citizen of the world. I’ve worried that today’s online ecosystem might quash the freedom to do this important experimentation. Kids seem to be tuned into this dilemma too.
Most parents thought they should probably ask their kid’s permission before posting more often. Indeed, they were right: The kids thought parents should ask for permission more often than they do. Previous work by Schoenebeck is in line with that sentiment: Children were twice as likely as parents to report that adults shouldn’t “overshare” by posting about children online without permission.

The issue of kid privacy extends beyond posting pictures, notes computer security and privacy expert Franziska Roesner. “Until what age do you track location on their phone, or even use the camera function on a baby monitor?” says Roesner, of the University of Washington in Seattle. “It’s an evolving space without clear answers.”

It’s too early to say how kids growing up in the current technology climate will feel about their parents’ sharing in hindsight. But a small study by Schoenebeck offers some insight. The researchers asked college students to reflect on their own potentially embarrassing teenage Facebook posts. The students valued the authenticity of their own historical content even if it was potentially embarrassing, Schoenebeck says. As one study participant put it: “When I look at [my old content], it’s kind of like ugh, like ‘yikes!’ [But] if someone finds it I’ll just be like, ‘yeah, I had a thing with song lyrics as my status when I was 15 years old. Get over it.’”

But just because kids didn’t mind their teenage posts surviving online, that doesn’t mean they won’t mind what you post about them. My daughter isn’t old enough yet to say, “You’re not the boss of me.” But I know that time is coming. Before that happens, I plan to start asking her permission about what I post about her and give her the option of deleting old posts.

Given the myriad other concerns parents have about kids and social media — from bullying to body image issues to what potential employers or colleges might see — asking our kids’ permission about what we share seems like an easy, thoughtful step to take.

Laura Sanders is away on maternity leave. Rachel Ehrenberg is a Boston-based science journalist and former reporter at Science News, with degrees in botany and evolutionary biology. She has raised many plants and is now trying to raise a human being.

Cracks open in the ground. Lava creeps across roads, swallowing cars and homes. Fountains of molten rock shoot up to 70 meters high, catching treetops on fire.

After a month of rumbling warning signs, Kilauea, Hawaii’s most active volcano, began a new phase of eruption last week. The volcano spewed clouds of steam and ash into the air on May 3, and lava gushed through several new rifts on the volcano’s eastern slope. Threatened by clouds of toxic sulfur dioxide–laden gas that also burst from the rifts, about 1,700 residents of a housing subdivision called Leilani Estates were forced to flee their homes, which sat directly in the path of the encroaching lava.
The event marks the 62nd eruption episode along Kilauea’s eastern flank, which is really part of an ongoing volcanic eruption that started in 1983. The volcano is one of six that formed Hawaii’s Big Island over the past million years. Mauna Loa is the largest and most central; Kilauea, Mauna Kea, Hualalai and Kohala occupy the island’s edges. Mahukona is currently submerged. All six are shield volcanoes, with broad flanks composed of hardened lava flows.

Kilauea’s activity has now shifted to its southeast flank, which continues to steam. No new rifts have opened since May 7, but the eruption may be far from over, says Victoria Avery, a volcanologist and associate program coordinator for the U.S. Geological Survey’s Volcano Hazards Program, based in Reston, Va.
Science News talked with Avery about Kilauea’s fury, the quakes and what to expect next from the volcano. Her responses were edited for brevity and clarity.
Q: Is there anything unusual about this eruption?

A: Not to scientists; it’s typical of what Kilauea volcano can do.

Q: Were there any warning signs?

A: We saw shallow earthquake activity under [the eastern flank of Kilauea] for several days. That tells us that molten rock is moving underground. We also saw that the lava lake at the summit of Kilauea was lowering; there’s a vent called Pu’u ‘O’o [which has erupted nearly continuously since 1983], and the floor [beneath its magma reservoir] collapsed on April 30. That told us that magma is being withdrawn and moved elsewhere. That collapse, plus the new seismicity, told us something was going to happen.
Q. On May 4, two large earthquakes measuring magnitude 5.4 and magnitude 6.9 shook the Big Island in quick succession. How are they related to the eruption?

A: It’s not frequent but not unusual for Hawaii to have earthquake[s] like that, because a volcano is a very dynamic place. The [surface swelling] associated with the eruption probably triggered the quake[s]: The magma pushed on the volcano from inside. The whole south flank of Kilauea is an area that has a history of large earthquakes. We didn’t directly anticipate it, but we weren’t that surprised when it happened.

Q: Did the people who live there know they were in a hazardous zone?

A: The eruption is right on one of the rift zones of the volcano. The fact that there was a subdivision right on top of it, I can’t comment on. But those houses are right where we know it can erupt. Right now, [emergency managers] are allowing people back in briefly to check on their homes, but not allowing them to stay.
Q: How dangerous is the gas that’s also erupting with the lava?

A: The gas is chiefly carbon dioxide and sulfur dioxide. The gas is actually what propels the [lava] to come out of the ground. Carbon dioxide in enough quantity can suffocate people. Sulfur dioxide can react with the atmosphere to create sulfuric acid. It forms “vog,” or volcanic fog, that can exacerbate asthma. That’s why they’re putting gas masks on people who go in to check on their homes.

Q: How are researchers monitoring this eruption?

A: We’re using the classic tools: instruments measuring seismicity and deformation, visual observations on the ground or flying over in helicopters, and thermal and deformation imagery from satellites. Using remote sensing, you can take [high-resolution images of ground elevation using] synthetic-aperture radar, or SAR, measurements at two different points in time to see the deformation.
Hawaii is a supersite, which means we get a lot of free SAR imagery over it, at about every two or three days. That may not be enough time for frequent eruption warnings, but it’s useful to monitor precursor activity and know what to look for. In the future, we’d like to use drones as well to monitor the eruptions.

Q: Nearby Mauna Loa is on yellow alert (to inform the aviation sector of potential ash hazards), because the volcano is showing signs of unrest. Is it at risk of erupting, too?

A: Mauna Loa really scares us. It is the largest volcano on the planet; it’s the big monster volcano of Hawaii. Kilauea has been erupting continuously since 1983, but Mauna Loa last erupted in 1984. But Mauna Loa can pump out much larger volumes and much faster. It has been yellow since September 2015, when there was elevated seismicity and deformation. It’s still a yellow, but it has quieted a bit.

Q: What’s next? Does the lull in activity at Kilauea mean the eruption is almost over?

A: It’s likely only a pause. The seismicity and deformation can wane and then build up again. The best we can do is watch precursor phenomena 24/7. [These include] the seismic data, the height of the lava lake and the deformation of the volcano along the rift zone. Where it swells, the magma is underneath it; where it goes down, the magma is withdrawing.

Q: The lava lake appears to be sinking again (as of May 6). Does that suggest more eruption is imminent?

A: It generally means that the lava is traveling down the rift zone. There’s likely more to come.

An asteroid that flouts the norms of the solar system might not be from around here.

The renegade asteroid travels around the sun in reverse — in the opposite direction of the planets and most other asteroids (SN: 5/13/17, p. 5). Now two scientists suggest that’s because the space rock originated from outside the solar system, according to a paper published May 21 in Monthly Notices of the Royal Astronomical Society Letters.

Astronomers Fathi Namouni of the Côte d’Azur Observatory in Nice, France, and Helena Morais of Universidade Estadual Paulista in Rio Claro, Brazil, used computer simulations to show that the asteroid, which shares its orbit with Jupiter, could have been traveling in reverse ever since the solar system’s youth. Because asteroids in the infant solar system formed from one swirling cloud, they should have all been traveling in the same direction. So the best explanation, the duo suggests, is that the rock, known as 2015 BZ509, migrated here from another star’s planetary system.
In 2017 astronomers spotted the first interstellar asteroid, dubbed ‘Oumuamua, which cruised through the solar system and back out again (SN Online: 12/1/17). Asteroid 2015 BZ509, however, appears to be a long-term inhabitant.
“It’s certainly an interesting possibility,” says astronomer Martin Connors of Athabasca University in Canada. But, he says, the study doesn’t nail down whether the asteroid actually came from outside the solar system.

Such asteroids are faint and hard to get information from, Connors says. “There isn’t really a blazing sign saying, ‘Hey, I’m not from here.’ ”

A space ravioli. A planetary baguette. A cosmic Kaiser roll. Some of Saturn’s moons have shapes that are strangely reminiscent of culinary concoctions.

Images of the oddball moons, mostly from the now-defunct Cassini spacecraft (SN Online: 9/15/17), got planetary scientists wondering how these satellites ended up with such strange shapes. Now, researchers suggest that collisions between young moonlets could have done the job, according to a study published online May 21 in Nature Astronomy.

Adrien Leleu , a planetary scientist at the University of Bern in Switzerland, and colleagues developed computer simulations that let the scientists virtually smack together similar-sized moonlets at various speeds and angles. The team found that, at low angles and relative speeds of tens of meters per second (roughly equal to a car on country roads), impacts can create offbeat shapes that look like the misfits around Saturn.
Head-on collisions result in a flattened moon like Pan, which resembles an empanada (SN Online: 3/10/17). An impact angle of just a few degrees leads to an elongated satellite such as Prometheus, which looks like a French loaf.
Not all run-ins create a weird looking moon. At higher angles, for example, moonlets might hit and run. Or they could form highly elongated rotating moons that subsequently break apart.
Leleu and collaborators focused on the smaller moons of Saturn that orbit within the planet’s rings. But the team also found that a similar collision between two larger moonlets could also account for the odd shape of Iapetus (SN Online: 4/21/14), a more distant walnut-shaped moon with a pronounced ridge along its equator that has puzzled scientists since the belt’s discovery. Other speculative origins for the ridge include volcanoes, plate tectonics or ring debris that rained down on the moon.

An account of another alleged “sonic attack” has surfaced, this time from a U.S. government employee in China. The employee reported “subtle and vague, but abnormal, sensations of sound and pressure,” according to a U.S. Embassy health alert. The episode mirrors reports from American diplomats in Cuba in late 2016, and fuels the debate among scientists about what, if anything, is actually happening.

Last year, 24 of the diplomats who reported sonic attacks in Cuba were tested to gauge whether lasting harm had occurred. In March, researchers from the University of Pennsylvania Perelman School of Medicine in Philadelphia reported in JAMA that the people had balance and thinking problems, sleep disturbances and headaches, and that some had widespread injury to brain networks.
But some scientists and engineers have been questioning whether such attacks are possible, and if the diplomats’ symptoms could have been caused by a sonic attack.

The attacks were supposedly committed with sounds outside the range of human hearing. But generating enough acoustical energy to cause hearing loss and brain damage from those types of sound waves would be no easy feat, says Andrew Oxenham, a hearing researcher at the University of Minnesota in Minneapolis. The intensity of very low frequency infrasound or very high frequency ultrasound drops rapidly over distance, so attackers would need enormous loud speakers to have enough intensity to do neurological harm.

“Even to get across the street and into a building, you’d have to have a loud speaker the size of a building,” Oxenham says.

It might be possible to focus ultrasound into a tight beam to stage a high-intensity ultrasound attack. But even with such a beam it would be difficult to make a device small enough to be used as a handheld weapon, says Tyrone Porter, a biomedical engineer at Boston University. And that device would be more likely to lead to disorientation than brain damage, he says.
Very little data exist on whether and how ultrasound in the air affects human health. One of the few people to tackle the question is Timothy Leighton, a professor of ultrasonics and underwater acoustics at the University of Southampton in England. He has investigated previous claims of people who complained that they had been victims of sonic attacks.
Some reported incidents were false alarms. But in other cases, Leighton recorded evidence of ultrasound in air at railway stations, museums and swimming pools where people had reported attacks, although the exposure was shown to be accidental, not an attack. He doesn’t know for sure how ultrasound causes symptoms such as the headaches and nausea described by the diplomats. But he suspects subaudible noise makes people anxious, which leads to the reported symptoms. The U.S. government employees in Cuba and China may be experiencing similar anxiety if exposed to ultrasound, he says.

Detected damage?
Leighton and other scientists have questioned whether the JAMA paper actually measured harm caused by a sonic attack. One symptom investigated in the study, white matter changes in the brain, made headlines. White matter is composed of axons, the long extensions of nerve cells that connect different parts of the brain.

“As a result, people got the impression this was some sort of ultrasonic death rifle,” Leighton says. But only three people in the study had white matter abnormalities, and the researchers couldn’t attribute those changes to a sonic attack. They may just have been physical differences that those people’s brains had all along.

What’s more, in the JAMA study, scores that classified diplomats as having a deficit in brain function fall into humans’ normal variation, says Sergio Della Sala, a cognitive neuroscientist at the University of Edinburgh.

The University of Pennsylvania researchers gave diplomats a failing grade on the brain tests if their score on at least one test was below the 40th percentile (meaning that 40 percent of people who take the tests have scores that fall at the low end of the scale), an impairment threshold that Della Sala argues is too high. That’s because, statistically speaking, people would get failing marks on at least one of these tests 40 percent of the time, even without an attack.

Only six of the 24 diplomats took all 37 tests, for 222 tests total. At the 40th percentile cutoff, 89 of the 222 tests would be false positives. That means a test-taker would flunk, but the result would be mistakenly chalked up to a sonic attack when it was really just a natural variation in the way people’s brains work.

In an experiment, Della Sala and University of Edinburgh colleague Robert McIntosh substituted random numbers for diplomats’ test scores and ran a simulation of possible outcomes, using the standards from the JAMA study. The result? “Everybody tested would result affected, everybody. To make sure, we repeated the simulation 1,000 times,” Della Sala wrote in an email.

He doesn’t dispute that some of the diplomats may have experienced symptoms from the incident. But the JAMA paper’s methods would make it impossible for anyone to test normal, he says. “The tests as they have been used and presented are spurious,” he wrote. (Della Sala, along with Roberto Cubelli of the University of Trento in Italy, also published a scathing review of the JAMA study in Cortex on April 5.)

One of the JAMA paper’s coauthors, Douglas Smith, says he and his colleagues have more data than were included in the study. “We note that interpretation of neuropsychological test results is somewhat more nuanced than a simple counting of scores that are lower than a conventional percentile cutoff point,” Smith wrote in an email. Instead, the researchers considered how much each person’s performance on a particular test differed from what is normal for the individual. In some cases, test scores in one aspect of brain function fell far below that person’s normal — down to the bottom 10 percent of the person’s average brain function. That low level of function counts as impairment, says Smith, who directs the Center for Brain Injury and Repair at the University of Pennsylvania’s medical school.

The researchers are currently trying to determine if the people felled by the attacks have changes in the structure of their brains that could account for the symptoms, Smith says.

Reverse engineering a ‘sonic weapon’
The sonic attacks may not have been attacks at all, but eavesdropping gone awry, says Kevin Fu, an electrical engineer and computer scientist at the University of Michigan in Ann Arbor. Fu, who studies how malicious sounds might be used to attack computers, has some of the only experimental evidence to suggest what might have happened in Cuba.

Fu’s attention was drawn to the attacks when the Associated Press released an audio clip of the sound some diplomats in Cuba heard during the incidents. He and colleagues Chen Yan and Wenyuan Xu, both of Zhejiang University in Hangzhou, China, tried to re-create the sound and surmised that an ultrasonic listening device could have developed interference that caused it to produce the unusual noise. “This seems like bad engineering rather than a deliberate attack,” Fu says.

Fu and colleagues described their experiment in a technical paper published online March 1. The researchers did not test whether such a device could have produced health and hearing problems for the diplomats.

For now, what actually happened in Cuba and China to produce the diplomats’ symptoms remains a mystery. And it’s possible we may never know. After all, Fu says, it’s unlikely that if foreign governments did have sonic weapons that they’d allow U.S. scientists to run experiments with the devices.

In the future, leaving your phone charger at home will mean only one thing: You forgot to put on pants.

Just as smartphones untethered users from their desktop computers, smart clothing is poised to bring personal electronics out of our pockets and onto our sleeves.

The current generation of wearable technology that includes smart glasses and watches is still more marginal than mainstream. Google Glass fizzled out, and nearly a third of the people who buy fitness trackers lose interest over time. But gadget-packed garments may have an edge when it comes to seamless integration into our lives.

“One conference, somebody stood up and [said], ‘I get that wearable technology is a thing, but I just don’t think I’m going to be willing to get up every single day and remember to put something on,’ ” recalls wearable technology researcher Lucy Dunne. “I looked at her and said, ‘You’re wearing clothes right now. I’m pretty sure you do that already.’ ”
Plus, technology-laden clothing is “right next to and against your body. It has a large surface area compared to personal devices, and it goes with us everywhere,” says Dunne, of the University of Minnesota campus in St. Paul. “That kind of access is … rich with opportunity.”

Some advanced apparel is already for sale, like gloves threaded with heat-conducting wires to warm fingers on extra cold days, or bathing suits equipped with UV sensors to alert suntanners when they are close to overbaked. But engineers have set their sights on a vast menu of souped-up clothes that could make daily life more convenient — or just better looking.
Job one, though, is to refashion conventional electronics. Typical battery packs and digital displays are too rigid and heavy for weaving into everyday duds. Engineers are getting creative to make lightweight, flexible devices that keep clothing comfortable and still perform as well as their clunky counterparts. Once researchers have built something that works well and is reasonably wearable, they still have to make sure their stuff is sturdy enough to withstand daily wear and tear, not to mention runs through the laundry.

Most next-gen clothing is years away from hitting retail racks. In fact, a lot of the tech hasn’t left the lab yet. But fashionistas and gearheads can look forward to a future where electronic clothes are in vogue. Here’s a sneak peek.

1. Change your fashion on the fly
   Clothing woven from color-changing yarns could give a whole new meaning to the phrase “goes with anything.”

Most existing color-changing textiles, like sun-activated T-shirts with designs that go from white to rainbow, are triggered by shifts in ambient lighting or body heat. Now, researchers have created clothes that change color with the tap of a smartphone screen.
These garments, presented April 4 in Phoenix at the Materials Research Society spring meeting, are made from yarns as thick as a few strands of human hair. Each yarn comprises a copper wire sheathed in a polymer sleeve. The polymer could be polyester, nylon or some other material, depending on how soft or sturdy you want your fabric, says optics and photonics researcher Joshua Kaufman, a codeveloper of the yarns at the University of Central Florida in Orlando.

The polymer sleeves are laced with pigments that shift color in response to temperature changes too subtle for the wearer to feel. The wearer controls the clothing’s appearance by sending Wi-Fi signals from a smartphone to a battery attached to the garment. The battery feeds electric current into the yarn’s copper wire, heating the pigment to activate a color switch. These yarns could make clothes that rotate between solids, stripes, plaids and other patterns.

Fashion trendsetters and people who just can’t decide what to wear in the morning probably stand the most to gain from this technology.

But it could have benefits for the rest of us, too. Spilled food on your light-colored shirt at lunch? Hide the stain with a darker hue. Want to wear a lighter shade when you’re out in the sun or biking home in the dark? Tap an app. Need to sneak in a second-day wear after skipping laundry day? No problem.

This kind of fabric could also be used for bags, car upholstery, curtains and furniture, says optics and photonics researcher Ayman Abouraddy, also at Central Florida. “We don’t anticipate more than a year or two before you could buy something [made of these fabrics] from the mall,” he says.

2. Never forget your ID or keys
   Someday, you may be able to embellish your clothes with enough data to get you in the building.

Researchers have created passcode-storing clothes made with thread that contains silver or copper filings. Normally, the magnetic poles of atoms in those metallic threads are pointed in random directions. But holding a magnet close to the thread aligns all the poles in a single section of cloth to point either north or south. Those magnetic orientations encode a bit of data, a 1 or 0, which an instrument called a magnetometer can read.

This data-embedded fabric, presented last October in Quebec City at the Association for Computing Machinery’s Symposium on User Interface Software and Technology, holds onto its magnetic information through washing, drying and ironing — at least for the short term. The strength of the data signal wanes by about 30 percent over the course of a week.

The material can be remagnetized with the same or a different pattern of 1s and 0s, but the researchers first have to build a device that can rewrite this data, similar to the tech used to reprogram hotel keycards, says Justin Chan, a computer scientist and engineer at the University of Washington in Seattle.

Chan and Washington colleague Shyam Gollakota have written magnetic codes into neckties, belts and wristbands, but the tech is still in the nascent stage. Right now, each 1 or 0 is about 2 centimeters across. The researchers are working on packing more data into smaller swatches, Chan says.

Once data-storing clothing is available, you could simply scan your sleeve to enter your office or apartment building. To some people, that may not seem like much of an advance. But the forgetful types who misplace their keys every other day might appreciate one less thing to scramble for on the way out the door.

3. Micromanage your moves
   Training yourself to drive a golf ball, play piano or just sit with better posture could get a whole lot easier, thanks to motion-sensing clothes that detect the slightest twitch.

“If you want to know exactly what somebody’s doing — whether or not they’re bending their knee in a healthy way, or what their heart rate and muscle activity is telling you about their emotional state — then you need sensors everywhere,” Dunne says.

To that end, industrial engineer Joshua DeGraff and colleagues have built superthin motion detectors that can be embedded in anything from shoulder braces to shoe soles.

The key component of these sensors is a sheet of material called buckypaper — a dense mesh of carbon nanotubes about as thick as a red blood cell is wide. Normally, buckypaper conducts electricity with no problem (SN: 3/8/14, p. 18). But stretching the material creates gaps in the nanotube network that stymie the flow of electric charge. DeGraff’s team at Florida State University in Tallahassee is using that weakness as an advantage. Connecting a piece of buckypaper to a circuit and measuring changes in electrical resistance across the paper can reveal how much the bucky-paper has been stretched.
Sensors fashioned by DeGraff’s team register as little as a 0.005 percent change in material length. The sensors, described last November in Materials and Design, could be powered by watch-sized batteries, DeGraff says.

Buckypaper sensors could prove useful for people who need to micromanage their movements in the short term — like physical therapy patients whose rehab requires them to move in exactly the way their therapist prescribed.

4. Add light to your life
   Light-up clothes of the future will look and feel less like your uncle’s ugly Christmas sweater and more like the sleek suits in the movie Tron: Legacy.

Actress Claire Danes lit up the 2016 Met Gala in a gown laced with LEDs. But standard, semiconductor-based LEDs are too stiff and brittle to make comfortable daywear, says Seonil Kwon, an engineer at the Korea Advanced Institute of Science and Technology in Daejeon, South Korea. Organic LEDs, or OLEDs, on the other hand, are razor-thin and superpliable.

An OLED display contains a layer cake of organic, or carbon-based, material films. The OLED lights up when a power source — like a battery — drives electric charge from one layer of organic material to another, where negative electrons pop into positive holes in the material. Whenever a positive hole and negative electron pair off, they release a brief flash of light. Many positive-negative meetups per second keep the OLED lit.
OLEDs are typically built on panes of plastic or glass, but Kwon and colleagues have created OLEDs on fabric. The researchers lay these OLEDs, just 200 nanometers thick, atop a polyester film that’s laminated onto fabric made of tightly woven, superfine polyester fibers. The setup is more flexible than the plastic platforms used to make bendy displays.

The new fabric-based OLEDs are bright enough to rival current display technology, Kwon and colleagues reported last July in Scientific Reports. Each OLED emits only a single color, but engineers could make fabric-based screens with many color-changing OLED pixels to display messages. Kwon’s group made OLED threads too, for lettering and patterns, reporting the work in the Jan. 10 Nano Letters.
Are there consumers who find the act of pulling a phone from their pocket so burdensome that they want to tote a smartphone screen on their sleeve? Who knows. But clothes sporting single-color OLEDs could light up pedestrians and bikers at night. Kwon also imagines creating OLED garments that glow white to provide light therapy. Some people who suffer from seasonal affective disorder find relief by sitting near a special lamp called a light therapy box, which gives off white light to mimic outdoor sunlight (SN: 4/23/05, p. 261). A shirt or underside of a hat brim that glows white could offer light therapy that goes where you go.

5. Power up with sun and your moves
   After a full day’s work, “no one wants to have to take off their shirt and plug it in,” says Rajan Kumar, a nanoengineer at the University of California, San Diego. Long battery life in smart clothing is key. So why not design wearables that continuously convert sunshine and motion energy into electricity?

Researchers debuted this kind of energy-harvesting fabric in 2016 in Nature Energy. Primarily made of synthetic polymers and wool fibers, the fabric is lightweight, flexible and breathable. A 4-by-5-centimeter piece worn for a run in the sun can charge up a cell phone, says Stanford University materials scientist and engineer Jun Chen, who did the work in the lab of Zhong Lin Wang at Georgia Tech.

The sunlight-catching patches of fabric are threaded with photovoltaic wires. When sunshine strikes a wire, light particles knock electrons out of atoms in one layer of material, leaving behind positively charged holes. Another electron-conducting layer of the wire collects those loose electrons, while a third layer gathers up the positively charged holes. That charge separation creates a voltage to produce electricity that can power devices.

Meanwhile, other patches of this fabric transform the energy of motion into electricity. These swatches contain strips of a polymer called PTFE — which hoards electrons — interlaced with copper wires — which easily give up electrons. Whenever the fabric is folded or compressed, some of the copper wires’ electrons rub off on the PTFE strips.
This process builds up static charge, just like combing your hair or peeling off a sweater in the winter. When the fabric relaxes, the negatively charged PTFE strips separate from the positive copper wires, creating voltage to power devices. Strips of this material could be sewn into sleeves to generate energy from the swing of your arms, or into the soles of shoes to get energy from footsteps, says Georgia Tech’s Wang, a materials scientist and engineer.

The energy this fabric gathers up when you’re moving around or sitting in the sun could also be stored in a capacitor or battery attached to the garment (SN: 11/26/16, p. 5). The storage device might be made of ink containing zinc-silver oxide printed directly onto clothing, as described in 2017 in Advanced Energy Materials. Or perhaps the energy could be stored in zinc-ion yarn batteries, like ones reported in the April 24 ACS Nano.

This energy-harvesting material could also be built into tents that, when bathed in sun or rustled by wind, could charge campers’ devices.

6. You as a walking generator
   If clothing were packed with thermoelectric generators, body heat could be turned into electricity.

Researchers at North Carolina State University in Raleigh work with a button-sized generator containing a grid of semiconductor rods sandwiched between two ceramic plates. When one side of the generator is hotter than the other — say, when that side is close to your skin while the other is exposed to air — electrons at the warm end of each semiconductor rod get jittery. These electrons diffuse toward the cold side of the device, creating a tiny voltage across the rod. Connecting the positive end of each rod to the negative end of the next adds up these voltages like stacking batteries in a flashlight.

Daryoosh Vashaee, an electrical engineer at NC State, and colleagues embedded these thermoelectric generators in a T-shirt. If someone wearing the shirt is just sitting around, the generator doesn’t produce much power because the temperature difference between skin and the surrounding air is so small. But if that person gets up and walks or jogs, a boost in body temperature will heat the side of the generator inside the T-shirt, while wind cools the exposed side of the generator. In one test, the generators pumped out six microwatts of power per square centimeter when the wearer was walking and 18 μW/cm2 during jogging, the researchers reported in 2016 in Applied Energy.

Unfortunately, that’s nowhere near enough to power a smartwatch or a phone. But generators a couple centimeters across could feed low-power sensors like heart monitors. And researchers are trying to boost the generators’ efficiency to support more power-hungry electronics. If researchers can make thermoelectric generators better powerhouses even when a wearer is seated, this tech would have one advantage over sunshine-motion harvesting clothing: You could power up your stuff while vegging out on the couch.

What felt like a miserable flu season this past year was, in fact, a miserable flu season.

The 2017–2018 influenza season was classified in the “high severity” category overall, according to a new report from the U.S. Centers for Disease Control and Prevention. It was only the third use of this designation since 2003.

To assess how the influenza virus has been affecting U.S. communities, the CDC applied a new method of evaluating severity to every annual outbreak back to the 2003–2004 season. The evaluation considers the percentage of flu-related visits to outpatient clinics, rates of hospitalizations and the percentage of deaths linked to flu or pneumonia.
The most recent flu season was among the worst for hospitalizations, the report finds, with the highest hospitalization rate for all ages combined since 2005–2006.

It was also a bad year for flu-related deaths among children, with 171 fatalities counted as of June 1, making it one of the deadliest in recent years. Only 22 percent of child victims who were eligible for the flu vaccine for the 2017–2018 season actually got vaccinated before becoming ill, researchers write in the June 8 Morbidity and Mortality Weekly Report.

Last season’s flu vaccine was about 36 percent effective overall, but only 25 percent against the predominant viruses from the H3N2 subtype of influenza A. However, even in years of low effectiveness, the flu vaccine is still the best protection against the illness, the CDC says (SN: 10/28/17, p. 18). The agency has yet to release estimates on how many illnesses were avoided this season because of vaccine use, but says vaccination prevented an estimated 5.29 million illnesses during the 2016–2017 season.