Science News INDEPENDENT JOURNALISM SINCE 1921 Sat, 21 Jan 2023 01:19:34 +0000 en-US hourly 1 Science News Fri, 20 Jan 2023 13:00:00 +0000 Rare earths are a valuable set of 17 elements needed to make everything from smartphones and electric vehicles to fluorescent bulbs and lasers. With global demand skyrocketing and China having a near-monopoly on rare earth production ?the United States has only one active mine ?there’s a lot of interest in finding alternative sources, such as ramping up recycling.

Pulling rare earths from coal waste offers a two-for-one deal: By retrieving the metals, you also help clean up the pollution. Long after a coal mine closes, it can leave a dirty legacy. When some of the rock left over from mining is exposed to air and water, sulfuric acid forms and pulls heavy metals from the rock. This acidic soup can pollute waterways and harm wildlife.

Recovering rare earths from what’s called acid mine drainage won’t single-handedly satisfy rising demand for the metals, acknowledges Paul Ziemkiewicz, director of the West Virginia Water Research Institute in Morgantown. But he points to several benefits.

Unlike ore dug from typical rare earth mines, the drainage is rich with the most-needed rare earth elements. Plus, extraction from acid mine drainage also doesn’t generate the radioactive waste that’s typically a by-product of rare earth mines, which often contain uranium and thorium alongside the rare earths. And from a practical standpoint, existing facilities to treat acid mine drainage could be used to collect the rare earths for processing. “Theoretically, you could start producing tomorrow,?Ziemkiewicz says. From a few hundred sites already treating acid mine drainage, nearly 600 metric tons of rare earth elements and cobalt ?another in-demand metal ?could be produced annually, Ziemkiewicz and colleagues estimate. Currently, a pilot project in West Virginia is taking material recovered from an acid mine drainage treatment site and extracting and concentrating the rare earths. If such a scheme proves feasible, Ziemkiewicz envisions a future in which cleanup sites send their rare earth hauls to a central facility to be processed, and the elements separated. Economic analyses suggest this wouldn’t be a get-rich scheme. But, he says, it could be enough to cover the costs of treating the acid mine drainage. ]]>
Science News Fri, 20 Jan 2023 13:00:00 +0000 Because of their special properties, these 17 metallic elements are crucial ingredients in computer screens, cell phones and other electronics, compact fluorescent lamps, medical imaging machines, lasers, fiber optics, pigments, polishing powders, industrial catalysts ?the list goes on and on (SN Online: 1/16/23). Notably rare earths are an essential part of the high-powered magnets and rechargeable batteries in the electric vehicles and renewable energy technologies needed to get the world to a low- or zero-carbon future.

In 2021, the world mined 280,000 metric tons of rare earths ?roughly 32 times as much as was mined in the mid-1950s. And demand is only going to increase. By 2040, experts estimate, we’ll need up to seven times as much rare earths as we do today.

Satisfying that appetite won’t be easy. Rare earth elements are not found in concentrated deposits. Miners must excavate huge amounts of ore, subject it to physical and chemical processes to concentrate the rare earths, and then separate them. The transformation is energy intensive and dirty, requiring toxic chemicals and often generating a small amount of radioactive waste that must be safely disposed of. Another concern is access: China has a near monopoly on both mining and processing; the United States has just one active mine (SN Online: 1/1/23).

For most of the jobs rare earths do, there are no good substitutes. So to help meet future demand and diversify who controls the supply ?and perhaps even make rare earth recovery “greener??researchers are looking for alternatives to conventional mining.   

Proposals include everything from extracting the metals from coal waste to really out-there ideas like mining the moon. But the approach most likely to make an immediate dent is recycling. “Recycling is going to play a very important and central role,?says Ikenna Nlebedim, a materials scientist at Ames National Laboratory in Iowa and the Department of Energy’s Critical Materials Institute. “That’s not to say we’re going to recycle our way out of the critical materials challenge.?

Still, in the rare earth magnets market, for instance, by about 10 years from now, recycling could satisfy as much as a quarter of the demand for rare earths, based on some estimates. “That’s huge,?he says. But before the rare earths in an old laptop can be recycled as regularly as the aluminum in an empty soda can, there are technological, economic and logistical obstacles to overcome.

Why are rare earths so challenging to extract?

Recycling seems like an obvious way to get more rare earths. It’s standard practice in the United States and Europe to recycle from 15 to 70 percent of other metals, such as iron, copper, aluminum, nickel and tin. Yet today, only about 1 percent of rare earth elements in old products are recycled, says Simon Jowitt, an economic geologist at the University of Nevada, Las Vegas.

“Copper wiring can be recycled into more copper wiring. Steel can just be recycled into more steel,?he says. But a lot of rare earth products are “inherently not very recyclable.?/p>

Rare earths are often blended with other metals in touch screens and similar products, making removal difficult. In some ways, recycling rare earths from tossed-out items resembles the challenge of extracting them from ore and separating them from each other. Traditional rare earth recycling methods also require hazardous chemicals such as hydrochloric acid and a lot of heat, and thus a lot of energy. On top of the environmental footprint, the cost of recovery may not be worth the effort given the small yield of rare earths. A hard disk drive, for instance, might contain just a few grams; some products offer just milligrams. Chemists and materials scientists, though, are trying to develop smarter recycling approaches. Their techniques put microbes to work, ditch the acids of traditional methods or attempt to bypass extraction and separation.

Microbial partners can help recycle rare earths

One approach leans on microscopic partners. Gluconobacter bacteria naturally produce organic acids that can pull rare earths, such as lanthanum and cerium, from spent catalysts used in petroleum refining or from fluorescent phosphors used in lighting. The bacterial acids are less environmentally harmful than hydrochloric acid or other traditional metal-leaching acids, says Yoshiko Fujita, a biogeochemist at Idaho National Laboratory in Idaho Falls. Fujita leads research into reuse and recycling at the Critical Materials Institute. “They can also be degraded naturally,?she says.

In experiments, the bacterial acids can recover only about a quarter to half of the rare earths from spent catalysts and phosphors. Hydrochloric acid can do much better — in some cases extracting as much as 99 percent. But bio-based leaching might still be profitable, Fujita and colleagues reported in 2019 in ACS Sustainable Chemistry & Engineering.

In a hypothetical plant recycling 19,000 metric tons of used catalyst a year, the team estimated annual revenues to be roughly $1.75 million. But feeding the bacteria that produce the acid on-site is a big expense. In a scenario in which the bacteria are fed refined sugar, total costs for producing the rare earths are roughly $1.6 million a year, leaving around just $150,000 in profits. Switching from sugar to corn stalks, husks and other harvest leftovers, however, would slash costs by about $500,000, raising profits to about $650,000.
a reactor machine at Idaho National Laboratory
One experimental recycling approach uses organic acids made by bacteria to extract rare earths from waste products. This reactor at the Idaho National Laboratory prepares an organic acid mixture for such recycling.Idaho National Lab

Other microbes can also help extract rare earths and take them even further. A few years ago, researchers discovered that some bacteria that metabolize rare earths produce a protein that preferentially grabs onto these metals. This protein, lanmodulin, can separate rare earths from each other, such as neodymium from dysprosium ?two components of rare earth magnets. A lanmodulin-based system might eliminate the need for the many chemical solvents typically used in such separation. And the waste left behind ?the protein ?would be biodegradable. But whether the system will pan out on a commercial scale is unknown.

How to pull rare earths from discarded magnets

Another approach already being commercialized skips the acids and uses copper salts to pull the rare earths from discarded magnets, a valuable target. Neodymium-iron-boron magnets are about 30 percent rare earth by weight and the single largest application of the metals in the world. One projection suggests that recovering the neodymium in magnets from U.S. hard disk drives alone could meet up about 5 percent of the world’s demand outside of China before the end of the decade. Nlebedim led a team that developed a technique that uses copper salts to leach rare earths out of shredded electronic waste that contains magnets. Dunking the e-waste in a copper salt solution at room temperature dissolves the rare earths in the magnets. Other can be scooped out for their own recycling, and the copper can be reused to make more salt solution. Next, the rare earths are solidified and, with the help of additional chemicals and heating, transformed into powdered minerals called rare earth oxides. The process, which has also been used on material left over from magnet manufacturing that typically goes to waste, can recover 90 to 98 percent of the rare earths, and the material is pure enough to make new magnets, Nlebedim’s team has demonstrated. In a best-case scenario, using this method to recycle 100 tons of leftover magnet material might produce 32 tons of rare earth oxides and net more than $1 million in profits, an economic analysis of the method suggests.

That study also evaluated the approach’s environmental impacts. Compared with producing one kilogram of rare earth oxide via one of the main types of mining and processing currently used in China, the copper salt method has less than half the carbon footprint. It produces an average of about 50 kilograms of carbon dioxide equivalent per kilogram of rare earth oxide versus 110, Nlebedim’s team reported in 2021 in ACS Sustainable Chemistry & Engineering.

But it’s not necessarily greener than all forms of mining. One sticking point is that the process requires toxic ammonium hydroxide and roasting, which consumes a lot of energy, and it still releases some carbon dioxide. Nlebedim’s group is now tweaking the technique. “We want to decarbonize the process and make it safer,?he says. Meanwhile, the technology seems promising enough that TdVib, an Iowa company that designs and manufactures magnetic materials and products, has licensed it and built a pilot plant. The initial aim is to produce two tons of rare earth oxides per month, says Daniel Bina, TdVib’s president and CEO. The plant will recycle rare earths from old hard disk drives from data centers. Noveon Magnetics, a company in San Marcos, Texas, is already making recycled neodymium-iron-boron magnets. In typical magnet manufacturing, the rare earths are mined, transformed into metal alloys, milled into a fine powder, magnetized and formed into a magnet. Noveon knocks out those first two steps, says company CEO Scott Dunn. After demagnetizing and cleaning discarded magnets, Noveon directly mills them into a powder before building them back up as new magnets. Unlike with other recycling methods, there’s no need to extract and separate the rare earths out first. The final product can be more than 99 percent recycled magnet, Dunn says, with a small addition of virgin rare earth elements ?the “secret sauce,?as he puts it ?that allows the company to fine-tune the magnets?attributes.

Compared with traditional magnet mining and manufacturing, Noveon’s method cuts energy use by about 90 percent, Miha Zakotnik, Noveon’s chief technology officer, and other researchers reported in 2016 in Environmental Technology & Innovation. Another 2016 analysis estimated that for every kilogram of magnet produced via Noveon’s method, about 12 kilograms of carbon dioxide equivalent are emitted. That’s about half as much of the greenhouse gas as conventional magnets.

Dunn declined to share what volume of magnets Noveon currently produces or how much its magnets cost. But the magnets are being used in some industrial applications, for pumps, fans and compressors, as well as some consumer power tools and other electronics.
photo of a robot named Daisy, developed by Apple
To help with recycling, Apple developed the robot Daisy (shown), which can dismantle 23 models of iPhones. Other robots in the works ?Taz and Dave ?will specialize in recovering rare earth magnets.Apple

Rare earth recycling has logistical hurdles

Even as researchers clear technological hurdles, there are still logistical barriers to recycling. “We don’t have the systems for collecting end-of-life products that have rare earths in them,?Fujita says, “and there’s the cost of dismantling those products.?For a lot of e-waste, before rare earth recycling can begin, you have to get to the bits that contain those precious metals. Noveon has a semiautomated process for removing magnets from hard disk drives and other electronics. Apple is also trying to automate the recycling process. The company’s Daisy robot can dismantle iPhones. And in 2022, Apple announced a pair of robots called Taz and Dave that facilitate the recycling of rare earths. Taz can gather magnet-containing modules that are typically lost during the shredding of electronics. Dave can recover magnets from taptic engines, Apple’s technology for providing users with tactile feedback when, say, tapping an iPhone screen. Even with robotic aids, it would still be a lot easier if companies just designed products in a way that made recycling easy, Fujita says.

No matter how good recycling gets, Jowitt sees no getting around the need to ramp up mining to feed our rare earth–hungry society. But he agrees recycling is necessary. “We’re dealing with intrinsically finite resources,?he says. “Better we try and extract what we can rather than just dumping it in the landfill.?/p> ]]> Science News Thu, 19 Jan 2023 19:00:00 +0000 Ongoing interbreeding between the two birds may threaten wild jungle fowl populations?future, and even hobble humans?ability to breed better chickens, researchers report January 19 in PLOS Genetics

Red jungle fowl (Gallus gallus) are forest birds native to Southeast Asia and parts of South Asia. Thousands of years ago, humans domesticated the fowl, possibly in the region’s rice fields (SN: 6/6/22). 

“Chickens are arguably the most important domestic animal on Earth,?says Frank Rheindt, an evolutionary biologist at the National University of Singapore. He points to their global ubiquity and abundance.  Chicken is also one of the cheapest sources of animal protein that humans have.

Domesticated chickens (G. gallus domesticus) were known to be interbreeding with jungle fowl near human settlements in Southeast Asia. Given the unknown impacts on jungle fowl and the importance of chickens to humankind, Rheindt and his team wanted to gather more details. Wild jungle fowl contain a store of genetic diversity that could serve as a crucial resource for breeding chickens resistant to diseases or other threats.

The researchers analyzed and compared the genomes ?the full complement of an organism’s DNA ?of 63 jungle fowl and 51 chickens from across Southeast Asia. Some of the jungle fowl samples came from museum specimens collected from 1874 through 1939, letting the team see how the genetic makeup of jungle fowl has changed over time.  Over the last century or so, wild jungle fowl’s genomes have become increasingly similar to chickens? Between about 20 and 50 percent of the genomes of modern jungle fowl originated in chickens, the team found. In contrast, many of the roughly 100-year-old jungle fowl had a chicken-ancestry share in the range of a few percent. The rapid change probably comes from human communities expanding into the region’s wilderness, Rheindt says. Most modern jungle fowl live in close vicinity to humans?free-ranging chickens, with which they frequently interbreed. 

Such interbreeding has become “almost the norm now?for any globally domesticated species, Rheindt says, such as dogs hybridizing with wolves and house cats crossing with wildcats. Pigs, meanwhile, are mixing with wild boars and ferrets with polecats.

Wild populations that interbreed with their domesticated counterparts could pick up physical or behavioral traits that change how the hybrids function in their ecosystem, says Claudio Quilodrán, a conservation geneticist at the University of Geneva not involved with this research.  The effect is likely to be negative, Quilodrán says, since some of the traits coming into the wild population have been honed for human uses, not for survival in the local environment.  Wild jungle fowl have lost their genetic diversity as they’ve interbred too. The birds?heterozygosity ?a measure of a population’s genetic diversity ?is now just a tenth of what it was a century ago. 

“This result is initially counterintuitive,?Rheindt says. “If you mix one population with another, you would generally expect a higher genetic diversity.?/p> But domesticated chickens have such low genetic diversity that certain versions of jungle fowl genes are being swept out of the population by a tsunami of genetic homogeneity. The whittling down of these animals?genetic toolkit may leave them vulnerable to conservation threats. “Having lots of genetic diversity within a species increases the chance that certain individuals contain the genetic background to adapt to a varied range of different environmental changes and diseases,?says Graham Etherington, a computational biologist at the Earlham Institute in Norwich, England, who was not involved with this research. A shallower jungle fowl gene pool could also mean diminished resources for breeding better chickens. The genetics of wild relatives are sometimes used to bolster the disease or pest resistance of domesticated crop plants. Jungle fowl genomes could be similarly valuable for this reason. “If this trend continues unabated, future human generations may only be able to access the entirety of ancestral genetic diversity of chickens in the form of museum specimens,?Rheindt says, which could hamper chicken breeding efforts using the wild fowl genes.  Some countries such as Singapore, Rheindt says, have started managing jungle fowl populations to reduce interbreeding with chickens. ]]> Science News Thu, 19 Jan 2023 19:00:00 +0000 The night sky has been brightening faster than researchers realized, thanks to the use of artificial lights at night. A study of more than 50,000 observations of stars by citizen scientists reveals that the night sky grew about 10 percent brighter, on average, every year from 2011 to 2022.

In other words, a baby born in a region where roughly 250 stars were visible every night would see only 100 stars on their 18th birthday, researchers report in the Jan. 20 Science.

The perils of light pollution go far beyond not being able to see as many stars. Too much brightness at night can harm people’s health, send migrating birds flying into buildings, disrupt food webs by drawing pollinating insects toward lights instead of plants and may even interrupt fireflies trying to have sex (SN: 8/2/17; SN: 8/12/15).

“In a way, this is a call to action,?says astronomer Connie Walker of the National Optical-Infrared Astronomy Research Laboratory in Tucson. “People should consider that this does have an impact on our lives. It’s not just astronomy. It impacts our health. It impacts other animals who cannot speak for themselves.?/p>

Walker works with the Globe at Night campaign, which began in the mid-2000s as an outreach project to connect students in Arizona and Chile and now has thousands of participants worldwide. Contributors compare the stars they can see with maps of what stars would be visible at different levels of light pollution, and enter the results on an app.

“I’d been quite skeptical of Globe at Night?as a tool for precision research, admits physicist Christopher Kyba of the GFZ German Research Centre for Geosciences in Potsdam. But the power is in the sheer numbers: Kyba and colleagues analyzed 51,351 individual data points collected from 2011 to 2022.

“The individual data are not precise, but there’s a whole lot of them,?he says. “This Globe at Night project is not just a game; it’s really useful data. And the more people participate, the more powerful it gets.?/p>

Those data, combined with a global atlas of sky luminance published in 2016, allowed the team to conclude that the night sky’s brightness increased by an average 9.6 percent per year from 2011 to 2022 (SN: 6/10/16).

Most of that increase was missed by satellites that collect brightness data across the globe. Those measurements saw just a 2 percent increase in brightness per year over the last decade. There are several reasons for that, Kyba says. Since the early 2010s, many outdoor lights have switched from high-pressure sodium lightbulbs to LEDs. LEDs are more energy efficient, which has environmental benefits and cost savings. But LEDs also emit more short-wavelength blue light, which scatters off particles in the atmosphere more than sodium bulbs?orange light, creating more sky glow. Existing satellites are not sensitive to blue wavelengths, so they underestimate the light pollution coming from LEDs. And satellites may miss light that shines toward the horizon, such as light emitted by a sign or from a window, rather than straight up or down.
satellite image of Milan at night taken from the International Space Station
Satellites have missed some of the light pollution from LEDs, which emit in blue wavelengths. This image from the International Space Station shows LEDs in the center of Milan glowing brighter than the orange lights in the suburbs.Samantha Cristoforetti, NASA, ESA

Astronomer and light pollution researcher John Barentine was not surprised that satellites underestimated the problem. But “I was still surprised by how much of an underestimate it was,?he says. “This paper is confirming that we’ve been undercounting light pollution in the world.?/p> The good news is that no major technological breakthroughs are needed to help fix the problem. Scientists and policy makers just need to convince people to change how they use light at night ?easier said than done.

“People sometimes say light pollution is the easiest pollution to solve, because you just have to turn a switch and it goes away,?Kyba says. “That’s true. But it’s ignoring the social problem ?that this overall problem of light pollution is made by billions of individual decisions.?/p> Some simple solutions include dimming or turning off lights overnight, especially floodlighting or lights in empty parking lots.

Kyba shared a story about a church in Slovenia that switched from four 400-watt floodlights to a single 58-watt LED, shining behind a cutout of the church to focus the light on its facade. The result was a 96 percent reduction in energy use and much less wasted light , Kyba reported in the International Journal of Sustainable Lighting in 2018. The church was still lit up, but the grass, trees and sky around it remained dark.

“If it was possible to replicate that story over and over again throughout our society, it would suggest you could really drastically reduce the light in the sky, still have a lit environment and have better vision and consume a lot less energy,?he says. “This is kind of the dream.?/p>

Barentine, who leads a private dark-sky consulting firm, thinks widespread awareness of the problem ?and subsequent action ?could be imminent. For comparison, he points to a highly publicized oil slick fire on the Cuyahoga River, outside of Cleveland, in 1969 that fueled the environmental movement of the 1960s and ?0s, and prompted the U.S. Congress to pass the Clean Water Act.

“I think we’re on the precipice, maybe, of having the river-on-fire moment for light pollution,?he says. ]]>
Science News Thu, 19 Jan 2023 14:00:00 +0000 Streptococcus salivarius. The mucus-loving bacteria boost inflammation, causing an endlessly runny nose.]]> Hay fever occurs when allergens, such as pollen or mold, trigger an inflammatory reaction in the nasal passages, leading to itchiness, sneezing and overflowing mucus. Researchers analyzed the composition of the microbial population in the noses of 55 people who have hay fever and those of 105 people who don’t. There was less diversity in the nasal microbiome of people who have hay fever and a whole lot more of a bacterial species called Streptococcus salivarius, the team reports online January 12 in Nature Microbiology.  

S. salivarius was 17 times more abundant in the noses of allergy sufferers than the noses of those without allergies, says Michael Otto, a molecular microbiologist at the National Institute of Allergy and Infectious Diseases in Bethesda, Md. That imbalance appears to play a part in further provoking allergy symptoms. In laboratory experiments with allergen-exposed cells that line the airways, S. salivarius boosted the cells?production of proteins that promote inflammation.

And it turns out that S. salivarius really likes runny noses. One prominent, unpleasant symptom of hay fever is the overproduction of nasal discharge. The researchers found that S. salivarius binds very well to airway-lining cells exposed to an allergen and slathered in mucus ?better than a comparison bacteria that also resides in the nose.

The close contact appears to be what makes the difference. It means that substances on S. salivarius?/em> surface that can drive inflammation ?common among many bacteria ?are close enough to exert their effect on cells, Otto says.

Hay fever, which disrupts daily activities and disturbs sleep, is estimated to affect as many as 30 percent of adults in the United States. The new research opens the door “to future studies targeting this bacteria?as a potential treatment for hay fever, says Mahboobeh Mahdavinia, a physician scientist who studies immunology and allergies at Rush University Medical Center in Chicago.

But any treatment would need to avoid harming the “good?bacteria that live in the nose, says Mahdavinia, who was not involved in the research.

The proteins on S. salivarius?surface that are important to its ability to attach to mucus-covered cells might provide a target, says Otto. The bacteria bind to proteins called mucins found in the slimy, runny mucus. By learning more about S. salivarius?surface proteins, Otto says, it may be possible to come up with “specific methods to block that adhesion.?/p> ]]> Science News Wed, 18 Jan 2023 14:00:00 +0000 A new approach to making tiny structures relies on shrinking them down after building them, rather than making them small to begin with, researchers report in the Dec. 23 Science.

The key is spongelike hydrogel materials that expand or contract in response to surrounding chemicals (SN: 1/20/10). By inscribing patterns in hydrogels with a laser and then shrinking the gels down to about one-thirteenth their original size, the researchers created patterns with details as small as 25 billionths of a meter across.

At that level of precision, the researchers could create letters small enough to easily write this entire article along the circumference of a typical human hair. Biological scientist Yongxin Zhao and colleagues deposited a variety of materials in the patterns to create nanoscopic images of Chinese zodiac animals. By shrinking the hydrogels after laser etching, several of the images ended up roughly the size of a red blood cell. They included a monkey made of silver, a gold-silver alloy pig, a titanium dioxide snake, an iron oxide dog and a rabbit made of luminescent nanoparticles.
two red dragons made from hydrogels
These two dragons, each roughly 40 micrometers long, were made by depositing cadmium selenide quantum dots onto a laser-etched hydrogel. The red stripes on the left dragon are each just 200 nanometers thick.The Chinese University of Hong Kong, Carnegie Mellon University
Because the hydrogels can be repeatedly shrunk and expanded with chemical baths, the researchers were also able to create holograms in layers inside a chunk of hydrogel to encode secret information. Shrinking a hydrogel hologram makes it unreadable. “If you want to read it, you have to expand the sample,?says Zhao, of Carnegie Mellon University in Pittsburgh. “But you need to expand it to exactly the same extent?as the original. In effect, knowing how much to expand the hydrogel serves as a key to unlock the information hidden inside.  

But the most exciting aspect of the research, Zhao says, is the wide range of materials that researchers can use on such minute scales. “We will be able to combine different types of materials together and make truly functional nanodevices.?/p> ]]> Science News Wed, 18 Jan 2023 12:00:00 +0000 Halteria ciliates can chow down solely on viruses. Whether these “virovores?do the same in the wild is unclear. ]]> Tiny, pond-dwelling Halteria ciliates are virovores, able to survive on a virus-only diet, researchers report December 27 in Proceedings of the National Academy of Sciences. The single-celled creatures are the first known to thrive when viruses alone are on the menu.

Scientists already knew that some microscopic organisms snack on aquatic viruses such as chloroviruses, which infect and kill algae. But it was unclear whether viruses alone could provide enough nutrients for an organism to grow and reproduce, says ecologist John DeLong of the University of Nebraska–Lincoln.

In laboratory experiments, Halteria that were living in water droplets and given only chloroviruses for sustenance reproduced, DeLong and colleagues found. As the number of viruses in the water dwindled, Halteria numbers went up. Ciliates without access to viral morsels, or any other food, didn’t multiply. But Paramecium, a larger microbe, didn’t thrive on a virus-only diet, hinting that viruses can’t satisfy the nutritional requirements for all ciliates to grow. 

Viruses could be a good source of phosphorus, which is essential for making copies of genetic material, DeLong says. But it probably takes a lot of viruses to account for a full meal.

In the lab, each Halteria microbe ate about 10,000 to 1 million viruses daily, the team estimates. Halteria in small ponds with abundant viral snacks might chow down on about a quadrillion viruses per day.

These feasts could shunt previously unrecognized energy into the food web, and add a new layer to the way viruses move carbon through an ecosystem ?if it happens in the wild, DeLong says (SN: 6/9/16). His team plans to start finding out once ponds in Nebraska thaw.  

Science News Wed, 18 Jan 2023 00:01:00 +0000 The spiny insectivores stay cool by blowing snot bubbles, researchers report January 18 in Biology Letters. The bubbles pop, keeping the critters?noses moist. As it evaporates, this moisture draws heat away from a blood-filled sinus in the echidna’s beak, helping to cool the animal’s blood.

Short-beaked echidnas (Tachyglossus aculeatus) look a bit like hedgehogs but are really monotremes ?egg-laying mammals unique to Australia and New Guinea (SN: 11/18/16). Previous lab studies showed that temperatures above 35° Celsius (95° Fahrenheit) should kill echidnas. But echidnas don’t seem to have gotten the memo. They live everywhere from tropical rainforests to deserts to snow-capped peaks, leaving scientists with a physiological puzzle.

Mammals evaporate water to keep cool when temperatures climb above their body temperatures, says environmental physiologist Christine Cooper of Curtin University in Perth, Australia. “Lots of mammals do that by either licking, sweating or panting,?she says. “Echidnas weren’t believed to be able to do that.?But it’s known that the critters blow snot bubbles when it gets hot. So, armed with a heat-vision camera and a telephoto lens, Cooper and environmental physiologist Philip Withers of the University of Western Australia in Perth drove through nature reserves in Western Australia once a month for a year to film echidnas. In infrared, the warmest parts of the echidnas?spiny bodies glowed in oranges, yellows and whites. But the video revealed that the tips of their noses were dark purple blobs, kept cool as moisture from their snot bubbles evaporated. Echidnas might also lose heat through their bellies and legs, the researchers report, while their spikes could act as an insulator.
An echidna looks like a hot spiky ball of yellow, orange and white in this heat-vision video ?except for its chilly nose, which shows up as a purple and black blob. That’s because these Australian mammals blow snot bubbles to keep their noses wet, which cools the critters down as the moisture evaporates, a new study concludes.
“Finding a way of doing this work in the field is pretty exciting,?says physiological ecologist Stewart Nicol of the University of Tasmania in Hobart, Australia, who was not involved in the study. “You can understand animals and see how they’re responding to their normal environment.?The next step, he says, is to quantify how much heat echidnas really lose through their noses and other body parts.

Monotremes parted evolutionary ways with other mammals between 250 million and 160 million years ago as the supercontinent Pangaea broke apart (SN: 3/8/15). So “they have a whole lot of traits that are considered to be primitive,?Cooper says. “Understanding how they might thermoregulate can give us some ideas about how thermal regulation ?might have evolved in mammals.?/p> ]]> Science News Tue, 17 Jan 2023 14:00:00 +0000 “In every sample we have seen of ancient Roman concrete, you can find these white inclusions,?bits of rock embedded in the walls. For many years, Masic says, the origin of those inclusions was unclear ?researchers suspected incomplete mixing of the cement, perhaps. But these are the highly organized Romans we’re talking about. How likely is it that “every operator [was] not mixing properly and every single [building] has a flaw??/p> What if, the team suggested, these inclusions in the cement were actually a feature, not a bug? The researchers?chemical analyses of such rocks embedded in the walls at the archaeological site of Privernum in Italy indicated that the inclusions were very calcium-rich. That suggested the tantalizing possibility that these rocks might be helping the buildings heal themselves from cracks due to weathering or even an earthquake. A ready supply of calcium was already on hand: It would dissolve, seep into the cracks and re-crystallize. Voila! Scar healed. But could the team observe this in action? Step one was to re-create the rocks via hot mixing and hope nothing exploded. Step two: Test the Roman-inspired cement. The team created concrete with and without the hot mixing process and tested them side by side. Each block of concrete was broken in half, the pieces placed a small distance apart. Then water was trickled through the crack to see how long it took before the seepage stopped.

“The results were stunning,?Masic says. The blocks incorporating hot mixed cement healed within two to three weeks. The concrete produced without hot mixed cement never healed at all, the team reports January 6 in Science Advances.

Cracking the recipe could be a boon to the planet. The Pantheon and its soaring, detailed concrete dome have stood nearly 2,000 years, for instance, while modern concrete structures have a lifespan of perhaps 150 years, and that’s a best case scenario (SN: 2/10/12). And the Romans didn’t have steel reinforcement bars shoring up their structures.

More frequent replacements of concrete structures means more greenhouse gas emissions. Concrete manufacturing is a huge source of carbon dioxide to the atmosphere, so longer-lasting versions could reduce that carbon footprint. “We make 4 gigatons per year of this material,?Masic says. That manufacture produces as much as 1 metric ton of CO2 per metric ton of produced concrete, currently amounting to about 8 percent of annual global CO2 emissions.

Still, Masic says, the concrete industry is resistant to change. For one thing, there are concerns about introducing new chemistry into a tried-and-true mixture with well-known mechanical properties. But “the key bottleneck in the industry is the cost,?he says. Concrete is cheap, and companies don’t want to price themselves out of competition.

The researchers hope that reintroducing this technique that has stood the test of time, and that could involve little added cost to manufacture, could answer both these concerns. In fact, they’re banking on it: Masic and several of his colleagues have created a startup they call DMAT that is currently seeking seed money to begin to commercially produce the Roman-inspired hot-mixed concrete. “It’s very appealing simply because it’s a thousands-of-years-old material.?/p> ]]> Science News Tue, 17 Jan 2023 12:00:00 +0000 CHICAGO ?In January 2022, a cyclone blitzed a large expanse of ice-covered ocean between Greenland and Russia. Frenzied gusts galvanized 8-meter-tall waves that pounded the region’s hapless flotillas of sea ice, while a bombardment of warm rain and a surge of southerly heat laid siege from the air.

Six days after the assault began, about a quarter, or roughly 400,000 square kilometers, of the vast area’s sea ice had disappeared, leading to a record weekly loss for the region.

The storm is the strongest Arctic cyclone ever documented. But it may not hold that title for long. Cyclones in the Arctic have become more frequent and intense in recent decades, posing risks to both sea ice and people, researchers reported December 13 at the American Geophysical Union’s fall meeting. “This trend is expected to persist as the region continues to warm rapidly in the future,?says climate scientist Stephen Vavrus of the University of Wisconsin–Madison.

Rapid Arctic warming and more destructive storms

The Arctic Circle is warming about four times as fast as the rest of Earth (SN: 8/11/22). A major driver is the loss of sea ice due to human-caused climate change. The floating ice reflects far more solar radiation back into space than naked seas do, influencing the global climate (SN: 10/14/21). During August, the heart of the sea ice melting season, cyclones have been observed to amplify sea ice losses on average, exacerbating warming.

There’s more: Like hurricanes can ravage regions farther south, boreal vortices can threaten people living and traveling in the Arctic (SN: 12/11/19). As the storms intensify, “stronger winds pose a risk for marine navigation by generating higher waves,?Vavrus says, “and for coastal erosion, which has already become a serious problem throughout much of the Arctic and forced some communities to consider relocating inland.?/p>

Climate change is intensifying storms farther south (SN: 11/11/20). But it’s unclear how Arctic cyclones might be changing as the world warms. Some previous research suggested that pressures, on average, in Arctic cyclones?cores have dropped in recent decades. That would be problematic, as lower pressures generally mean more intense storms, with “stronger winds, larger temperature variations and heavier rainfall [and] snowfall,?says atmospheric scientist Xiangdong Zhang of the University of Alaska Fairbanks.

But inconsistencies between analyses had prevented a clear trend from emerging, Zhang said at the meeting. So he and his colleagues aggregated a comprehensive record, spanning 1950 to 2021, of Arctic cyclone timing, intensity and duration.

Arctic cyclone activity has intensified in strength and frequency over recent decades, Zhang reported. Pressures in the hearts of today’s boreal vortices are on average about 9 millibars lower than in the 1950s. For context, such a pressure shift would be roughly equivalent to bumping a strong category 1 hurricane well into category 2 territory. And vortices became more frequent during winters in the North Atlantic Arctic and during summers in the Arctic north of Eurasia.

What’s more, August cyclones appear to be damaging sea ice more than in the past, said meteorologist Peter Finocchio of the U.S. Naval Research Laboratory in Monterey, Calif. He and his colleagues compared the response of northern sea ice to summer cyclones during the 1990s and the 2010s.

August vortices in the latter decade were followed by a 10 percent loss of sea ice area on average, up from the earlier decade’s 3 percent loss on average. This may be due, in part, to warmer water upwelling from below, which can melt the ice pack’s underbelly, and from winds pushing the thinner, easier-to-move ice around, Finocchio said.

Stronger spring storms spell trouble too

With climate change, cyclones may continue intensifying in the spring too, climate scientist Chelsea Parker said at the meeting. That’s a problem because spring vortices can prime sea ice for later summer melting.

Parker, of NASA’s Goddard Space Flight Center in Greenbelt, Md., and her colleagues ran computer simulations of spring cyclone behavior in the Arctic under past, present and projected climate conditions. By the end of the century, the maximum near-surface wind speeds of spring cyclones ?around 11 kilometers per hour today ?could reach 60 km/h, the researchers found. And future spring cyclones may keep swirling at peak intensity for up to a quarter of their life spans, up from around 1 percent today. The storms will probably travel farther too, the team says. “The diminishing sea ice cover will enable the warmer Arctic seas to fuel these storms and probably allow them to penetrate farther into the Arctic,?says Vavrus, who was not involved in the research. Parker and her team plan to investigate the future evolution of Arctic cyclones in other seasons, to capture a broader picture of how climate change is affecting the storms. For now, it seems certain that Arctic cyclones aren’t going anywhere. What’s less clear is how humankind will contend with the storms’ growing fury. ]]>
Science News Mon, 16 Jan 2023 16:00:00 +0000 In a mountaintop experiment, such a laser bent lightning toward a lightning rod, researchers report online January 16 in Nature Photonics. Scientists have used lasers to wrangle electricity in the lab before, but this is the first demonstration that the technique works in real-world storms and could someday lead to better protection against lightning.

Today’s most common anti-lightning tech is the classic lightning rod, a meters-long metal pole rooted to the ground. The metal’s conductivity lures in lightning that might otherwise strike nearby buildings or people, feeding that electricity safely into the earth. But the area shielded by a lightning rod is limited by the rod’s height. “If you want to protect some large infrastructure, like an airport or a launching pad for rockets or a wind farm ?then you would need, for good protection, a lightning rod of kilometer size, or hundreds of meters,?says Aurélien Houard, a physicist at Institut Polytechnique de Paris in Palaiseau, France. Such a tall metal pole would be impractical. But a laser could reach that far, intercepting distant lightning bolts and ushering them down to ground-based metal rods. Houard and his colleagues tested this idea atop the Säntis mountain in northeastern Switzerland. They set up a high-power laser near a telecommunications tower tipped with a lightning rod that is struck by lightning around 100 times every year. The laser was beamed at the sky for about six hours total during thunderstorms from July to September 2021.
A high-speed camera image of a tangled lightning bolt curving toward and then down a lightning rod
On July 24, 2021, fairly clear skies allowed a high-speed camera to capture the moment that a laser bent the path of a lightning bolt between the sky and a lightning rod atop a tower. The lightning followed the route of the laser light for some 50 meters.A. Houard et al/Nature Photonics 2023

The laser blasted short, intense bursts of infrared light at the clouds about 1,000 times per second. This train of light pulses ripped electrons off air molecules and knocked some air molecules out of its way, carving out a channel of low-density, charged plasma. Sort of like clearing a path through the woods and laying down pavement, this combination of effects made it easier for electric current to flow along this route (SN: 3/5/14). That created a path of least resistance for lightning to follow through the sky.

Houard’s team tuned their laser so that it formed this electrically conductive pathway just above the tip of the tower. This allowed the tower’s lightning rod to intercept a bolt snagged by the laser before it zipped all the way down to the laser equipment. The tower was hit by lightning four times while the laser was on. One of those strikes happened in a fairly clear sky, allowing two high-speed cameras to capture the moment. Those images showed lightning zigzagging down from the clouds and following the laser light for some 50 meters toward the tower’s lightning rod. To track the paths of the three bolts that they could not see, the researchers looked at radio waves shed by the lightning. Those radio waves showed that the three strikes followed the path of the laser much more closely than other strikes that happened when the laser was off. This hinted that the laser guided these three strikes to the lightning rod, as well.
This 3-D reconstruction models a lightning strike captured by high-speed cameras in July 2021. It shows the moment that the lightning bolt hit a metal rod atop a tower, its path guided through the sky by a powerful laser.

“It’s a real achievement,?says Howard Milchberg, a physicist at the University of Maryland in College Park not involved in the work. “People have been trying to do this for many years.?Scientists?main goal in bending lightning to their will is to increase safety, he says. But “if this thing ever became really, really efficient, and the probability of guiding a discharge was increased way beyond what it is now, it could potentially even be useful for charging things up.?/p> Atmospheric and space scientist Robert Holzworth is more cautious about imagining the applications. “They only showed 50 meters of [guiding] length, and most lightning channels are kilometers long,?says Holzworth, of the University of Washington in Seattle. So scaling the laser system up to have a useful reach may take a lot of work.

Using a higher-frequency, higher-energy laser could extend its reach, Houard says. “This is a first step toward a kilometric-range lightning rod.?/p> ]]> Science News Mon, 16 Jan 2023 13:00:00 +0000 In Frank Herbert’s space opera Dune, a precious natural substance called spice melange grants people the ability to navigate vast expanses of the cosmos to build an intergalactic civilization.

In real life here on Earth, a group of natural metals known as the rare earths has made possible our own technology-powered society. Demand for these crucial components in nearly all modern electronics is skyrocketing. Rare earths fulfill thousands of different needs ?cerium, for instance, is used as a catalyst to refine petroleum, and gadolinium captures neutrons in nuclear reactors. But these elements?most outstanding capabilities lie in their luminescence and magnetism. We rely on rare earths to color our smartphone screens, fluoresce to signal authenticity in euro banknotes and relay signals through fiber-optic cables across the seafloor. They are also essential for building some of the world’s strongest and most reliable magnets. They generate sound waves in your headphones, boost digital information through space and shift the trajectories of heat-seeking missiles. Rare earths are also driving the growth of green technologies, such as wind energy and electric vehicles, and may even give rise to new components for quantum computers.

“The list just goes on and on,?says Stephen Boyd, a synthetic chemist and independent consultant. “They’re everywhere.?/p>

Rare earths?superpowers come from their electrons

The rare earths are the lanthanides ?lutetium and all 14 elements between lanthanum and ytterbium across one row of the periodic table ?plus scandium and yttrium, which tend to occur in the same ore deposits and have similar chemical properties to the lanthanides. These gray to silvery metals are often malleable with high melting and boiling points. Their secret powers lie in their electrons. All atoms have a nucleus surrounded by electrons, which inhabit zones called orbitals. Electrons in the orbitals farthest from the nucleus are the valence electrons, which participate in chemical reactions and form bonds with other atoms. Most lanthanides possess another important set of electrons called the “f-electrons,?which dwell in a Goldilocks zone located near the valence electrons but slightly closer to the nucleus. “It’s these f-electrons that are responsible for both the magnetic and luminescent properties of the rare earth elements,?says Ana de Bettencourt-Dias, an inorganic chemist at the University of Nevada, Reno.

Rare earths add color and light

Along some coasts, the night sea occasionally glows bluish green as bioluminescent plankton are jostled in the waves. Rare earth metals also radiate light when stimulated. The trick is to tickle their f-electrons, de Bettencourt-Dias says.

Using an energy source like a laser or lamp, scientists and engineers can jolt one of a rare earth’s f-electrons into an excited state and then let it fall back into lethargy, or its ground state. “When the lanthanides come back to the ground state,?she says, “they emit light.?/p> Each rare earth reliably emits precise wavelengths of light when excited, de Bettencourt-Dias says. This dependable precision allows engineers to carefully tune electromagnetic radiation in many electronics. Terbium, for instance, emits light at a wavelength of about 545 nanometers, making it good for constructing green phosphors in television, computer and smartphone screens. Europium, which has two common forms, is used to build red and blue phosphors. All together, these phosphors can paint screens with most shades of the rainbow. Rare earths also radiate useful invisible light. Yttrium is a key ingredient in yttrium-aluminum-garnet, or YAG, a synthetic crystal that forms the core of many high-powered lasers. Engineers tune the wavelengths of these lasers by lacing YAG crystals with another rare earth. The most popular variety are neodymium-laced YAG lasers, which are used for everything from slicing steel to removing tattoos to laser range-finding. Erbium-YAG laser beams are a good option for minimally invasive surgeries because they’re readily absorbed by water in flesh and thus won’t slice too deep.

See how the europium in embedded fibers in a Euro banknote fluoresces under ultraviolet light. The UV light excites the europium’s f-electrons, which then fall back into their ground state and release photons of visible light in the process.
Left: GagogaSus/Wikimedia Commons (CC BY-SA 4.0); Right: ECB/Reinhold Gerstetter/Wikimedia Commons
Beyond lasers, lanthanum is crucial for making the infrared-absorbing glass in night vision goggles. “And erbium drives our internet,?says Tian Zhong, a molecular engineer at the University of Chicago. Much of our digital information travels through optical fibers as light with a wavelength of about 1,550 nanometers ?the same wavelength erbium emits. The signals in fiber-optic cables dim as they travel far from their source. Because those cables can stretch for thousands of kilometers across the seafloor, erbium is added to fibers to boost signals.

Rare earths make mighty magnets

In 1945, scientists constructed ENIAC, the world’s first programmable, general purpose digital computer (SN: 2/23/46, p. 118). Nicknamed the “Giant Brain,?ENIAC weighed more than four elephants and had a footprint roughly two-thirds the size of a tennis court.

Less than 80 years later, the ubiquitous smartphone ?boasting far more computing power than ENIAC ever did ?fits snugly in our palms. Society owes this miniaturization of electronic technology in large part to the exceptional magnetic power of the rare earths. Tiny rare earth magnets can do the same job as larger magnets made without rare earths.

It’s those f-electrons at play. Rare earths have many orbitals of electrons, but the f-electrons inhabit a specific group of seven orbitals called the 4f-subshell. In any subshell, electrons try to spread themselves out among the orbitals within. Each orbital can house up to two electrons. But since the 4f-subshell contains seven orbitals, and most rare earths contain fewer than 14 f-electrons, the elements tend to have multiple orbitals with just one electron. Neodymium atoms, for instance, possess four of these loners, while dysprosium and samarium have five. Crucially, these unpaired electrons tend to point ?or spin ?in the same direction, Boyd says. “That’s what creates the north and the south poles that we classically understand as magnetism.?/p> Since these lone f-electrons flitter behind a shell of valence electrons, their synchronized spins are somewhat shielded from demagnetizing forces such as heat and other magnetic fields, making them great for building permanent magnets, Zhong says. Permanent magnets, like the ones that hold up pictures on a fridge door, passively generate magnetic fields that arise from their atomic structure, unlike electromagnets, which require an electric current and can be turned off.

But even with their shielding, the rare earths have limits. Pure neodymium, for example, readily corrodes and fractures, and its magnetic pull begins to lose strength above 80° Celsius. So manufacturers alloy some rare earths with other metals to make more resilient magnets, says Durga Paudyal, a theoretical physicist at Ames National Laboratory in Iowa. This works well because some rare earths can orchestrate the magnetic fields of other metals, he says. Just as weighted dice will preferentially land on one side, some rare earths like neodymium and samarium exhibit stronger magnetism in certain directions because they contain unevenly filled orbitals in their 4f-subshells. This directionality, called magnetic anisotropy, can be leveraged to coordinate the fields of other metals like iron or cobalt to formulate robust, extremely powerful magnets.

The most powerful rare earth alloy magnets are neodymium-iron-boron magnets. A three-kilogram neodymium alloy magnet can lift objects that weigh over 300 kilograms, for instance. More than 95 percent of the world’s permanent magnets are made from this rare earth alloy. Neodymium-iron-boron magnets generate vibrations in smartphones, produce sounds in earbuds and headphones, enable the reading and writing of data in hard disk drives and generate the magnetic fields used in MRI machines. And adding a bit of dysprosium to these magnets can boost the alloy’s heat resistance, making it a good choice for the rotors that spin in the hot interiors of many electric vehicle motors.

Samarium-cobalt magnets, developed in the 1960s, were the first popular rare earth magnets. Though slightly weaker than neodymium-iron-boron magnets, samarium-cobalt magnets have superior heat and corrosion resistance, so they’re put to work in high-speed motors, generators, speed sensors in cars and airplanes, and in the moving parts of some heat-seeking missiles. Samarium-cobalt magnets also form the heart of most traveling-wave tubes, which boost signals from radar systems and communications satellites. Some of these tubes are transmitting data from the Voyager 1 spacecraft ?currently the most distant human-made object ?over 23 billion kilometers away (SN: 7/31/21, p. 18).

Because they are strong and reliable, rare earth magnets are supporting green technologies. They’re in the motors, drivetrains, power steering and many other components of electric vehicles. Tesla’s use of neodymium alloy magnets in its farthest-ranging Model 3 vehicles has sparked supply chain worries; China provides the vast majority of the world’s neodymium (SN: 1/11/23).

Rare earth magnets are also used in many offshore wind turbines to replace gearboxes, which boosts efficiency and decreases maintenance. In August, Chinese engineers introduced “Rainbow,?the world’s first maglev train line based on rare earth magnets that enable the trains to float without consuming electricity. In the future, rare earths may even advance quantum computing. While conventional computers use binary bits (those 1s and 0s), quantum computers use qubits, which can occupy two states simultaneously. As it turns out, crystals containing rare earths make good qubits, since the shielded f-electrons can store quantum information for long periods of time, Zhong says. One day, computer scientists might even leverage the luminescent properties of rare earths in qubits to share information between quantum computers and birth a quantum internet, he says. It may be too early to predict exactly how the rare earth metals will continue to influence the expansion of these growing technologies. But it’s probably safe to say: We’re going to need more rare earths. ]]>
Science News Fri, 13 Jan 2023 21:01:10 +0000 But while previous variants such as alpha, delta and the original omicron were linked to massive surges of new infections, it’s not yet clear whether XBB.1.5 is destined for a similar path (SN: 12/21/21). Preliminary evidence suggests the subvariant, nicknamed the Kraken in some circles, is more transmissible than its predecessors. That trait, however, is a hallmark of viral evolution ?successful new variants must be able to outcompete their siblings (SN: 5/26/20). 

For now, experts at the World Health Organization are keeping a close eye on XBB.1.5. But it’s too early to say whether it might take over the globe. Most cases currently come from the United States, the United Kingdom and Denmark.

Science News spoke with infectious diseases specialist Peter Chin-Hong of the University of California, San Francisco about the latest coronavirus variant to make headlines. The conversation has been edited for length and clarity.   

SN: What is the difference between XBB.1.5 and earlier versions of omicron?

Chin-Hong: There are lots of variants that get produced all the time. It’s a normal thing for the virus as the virus makes more copies of itself. It’s not exactly precise or accurate, so it makes errors, [which are the variants]. It’s kind of like a bad photocopy machine in the office. 

XBB, a sibling of XBB.1.5, was scary ?and that was seen in the fall of 2022 ?because it was one of the most immune-evasive variants around. But the reason why XBB never took off around the world ?it was really in Singapore and India ?was that it didn’t really infect cells quite as well. 

XBB.1.5 has the immune slipperiness of XBB, but it also has this new mutation that makes it easy to infect cells. So it’s kind of like a bulldog in not wanting to let go of the cell. Whereas XBB was kind of invisible, like it had the invisibility cloak from Harry Potter, it didn’t have the bite. But XBB.1.5 has the invisibility cloak, plus the bite. 

SN: Is that why it’s spreading so effectively in some areas?

Chin-Hong: We think so. Because to be very efficient at infecting cells is a really important superpower if you are a virus. 

You can be invisible [to the immune system] all you want, but if you’re not infecting cells efficiently, you probably won’t be as infectious. That could be [the reason] XBB.1.5 is spreading, because it has both of those things going for it. Seeing how it’s crowding out the other variants now makes us worried that it’s something to pay attention to. And it’s accompanied by increasing cases and hospitalizations.  

SN: Previous variants were linked to big surges of infections. Can we expect the same of XBB.1.5?

Chin-Hong: It’s complicated. If it were March 2020, it would be a very simple answer: Yes. But in January of 2023, you have so much variation in the amount of experience people have toward COVID, even if it’s a different type. 

You can have somebody who got infected two or three times plus they got vaccinated and boosted. That’s going to be somebody who’s going to be really, really well protected against getting seriously ill. Maybe they might get a cold. Maybe they wouldn’t even know they had an infection versus somebody who didn’t get vaccinated and never got exposed and they’re older. It might as well be March of 2020 for them.  That [second] kind of person is, for example, in China. In China, XBB.1.5 might cause a lot of problems. But XBB.1.5 going to, you know, the middle of Manhattan might not cause as many problems in a highly vaccinated and exposed group of people.  [Timing also matters] because we saw a lot of BQ.1, BQ.1.1 recently, and a lot of people got infected after Thanksgiving. This rise of XBB.1.5 is coming after a lot of people already got infected recently. So it probably won’t do as much damage as if you had a long lull and all of a sudden you have this new thing. 

SN: Do vaccines and treatments still work against it?

Chin-Hong: The new updated boosters generally work a little better than the old vaccines in terms of overall efficacy and preventing infection. But with these new slippery variants like XBB.1.5 ?if you’re looking to prevent infections, even a mild infection, the vaccines are probably going to last maybe three months. 

But if you’re talking about preventing me from dying or going to the hospital, those vaccines are going to give me a boost of protection for many, many months, probably until next winter for most people. For older people, older than 65, if they’re not boosted today, then it’s a problem.

[Drugs such as] Paxlovid and remdesivir work independent of the spike protein [the part of the virus targeted by vaccines but where many of the defense-evading mutations are (SN: 3/1/22)]. So it doesn’t matter what invisibility cloak the variant has. They’re going to work because they work on shutting down the virus factory, which is one of the early steps, before the spike protein gets made. 

So they will work no matter what [spike] variant comes along, which is a good thing. Even if you didn’t get vaccinated or never got exposed, if you got diagnosed and you get early therapy, it will cut down your hospitalization rates substantially. 

Now, all monoclonal antibodies don’t work. [The virus has changed too much (SN: 10/17/22).]   

SN: Why is it that only omicron variants are popping up? 

Chin-Hong: I think omicron has hit on a magical formula. It’s going to be hard to kick it off the gold medal stand. It’s so good at transmission, and all these other aspects that are good for the virus. 

In the [earlier] days, it was two or three months, and you had a new coronavirus variant somewhere in the world. Now it’s been omicron since two Thanksgivings ago. 

SN: With each variant more transmissible than the last, is it inevitable that everyone will get COVID? 

Chin-Hong: The people who didn’t get infected before are going to have a really, really hard time escaping this one. But it’s not impossible. It’s just going to be harder and harder, not only because XBB.1.5 is so transmissible, but also because we don’t have so many restrictions anymore. You’re going to the grocery store, nobody’s wearing a mask or you don’t feel like you have peer pressure to wear masks. So you’re going to get exposed just like you get exposed to colds? 

But you can reduce the risk in the short term by getting a booster, if you haven’t already gotten one. And certainly [the booster] can reduce the risk of dying, particularly if you’re older or immune-compromised?  [People still wearing masks] have to wear really good quality masks [such as KN95s] because you can’t rely on everybody else wearing masks anymore.

SN: How worried should people be about XBB.1.5?

Chin-Hong: The world is divided into two groups of people. The people whose bodies are very, very experienced with COVID ?it’s gotten vaccines or boosting or ?a couple of infections. And then there are people whose body isn’t well-experienced with COVID. For that [latter] group, they should be worried. 

For someone, you’re looking around and your neighbor got it and nothing happened, or your cousin or a person at work, and it’s like it’s no big deal. But there are still 500 people dying every day in the United States [from COVID]. And to those people, it’s a huge deal? It’s a weird situation because it’s not one-size-fits-all anymore, and different people have different levels of risk.  ]]>
Science News Fri, 13 Jan 2023 14:00:00 +0000 “It’s like Buffalo, but worse,?says planetary scientist Emily Martin, referring to the famously snowy city in New York. The snow depth suggests that Enceladus?dramatic plume may have been more active in the past, Martin and colleagues report in the Mar. 1 Icarus.

Planetary scientists have been fascinated by Enceladus?geysers, made up of water vapor and other ingredients, since the Cassini spacecraft spotted them in 2005 (SN: 12/16/22). The spray probably comes from a salty ocean beneath an icy shell.

Some of that water goes to form one of Saturn’s rings (SN: 5/2/06). But most of it falls back onto the moon’s surface as snow, Martin says. Understanding the properties of that snow ?its thickness and how dense and compact it is ?could help reveal Enceladus?history, and lay groundwork for future missions to this moon.

“If you’re going to land a robot there, you need to understand what it’s going to be landing into,?says Martin, of the National Air and Space Museum in Washington, D.C.

To figure out how thick Enceladus?snow is, Martin and colleagues looked to Earth ?specifically, Iceland. The island country hosts geological features called pit chains, which are lines of pockmarks in the ground formed when loose rubble such as rocks, ice or snow drains into a crack underneath (SN: 10/23/18). Similar features show up all over the solar system, including Enceladus.

A person walks near pit chain craters in Iceland.
Pit chain craters in Iceland, like those shown here, helped planetary scientist Emily Martin and colleagues verify that they could measure the depth of craters on Enceladus. Martin took this image during a field excursion.E. Martin

Previous work suggested a way to use geometry and the angle at which sunlight hits the surface to measure the depth of the pits. That measurement can then reveal the depth of the material the pits sit in. A few weeks of fieldwork in Iceland in 2017 and 2018 convinced Martin and her colleagues that the same technique would work on Enceladus.

Using images from Cassini, Martin and colleagues found that the snow’s thickness varies across Enceladus?surface. It is hundreds of meters deep in most places and 700 meters deep at its thickest. It’s hard to imagine how all that snow got there, though, Martin says. If the plume’s spray was always what it is today, it would take 4.5 billion years ?the entire age of the solar system ?to deposit that much snow on the surface. Even then, the snow would have to be especially fluffy. It seems unlikely that the plume switched on the moment the moon formed and never changed, Martin says. And even if it did, later layers of snow would have compressed the earlier ones, compacting the whole layer and making it much less deep than it is today.

“It makes me think we don’t have 4.5 billion years to do this,?Martin says. Instead, the plume might have been much more active in the past. “We need to do it in a much shorter timeframe. You need to crank up the volume on the plume.?/p>

The technique was clever, says planetary scientist Shannon MacKenzie of the Johns Hopkins University Applied Physics Laboratory in Laurel, Md. Without rovers or astronauts on the ground, there’s no way to scoop up the snow and see how far down it goes. “Instead, the authors are very cleverly using geology to be their rovers, to be their shovels.?/p>

MacKenzie was not involved in the new work, but she led a mission concept study for an orbiter and lander that could one day visit Enceladus. One of the major questions in that study was where a lander could safely touch down. “Key to those discussions was, what do we expect the surface to be??she says. The new paper could help “identify the places that are too fluffy to land in.?/p> ]]> Science News Thu, 12 Jan 2023 15:00:00 +0000 And a new, large study brings fresh doubt. High levels of HDL cholesterol were not associated with protection against heart disease in Black or white participants, researchers reported in the November Journal of the American College of Cardiology. For low levels of HDL cholesterol, there was a split, with a link to higher risk of heart disease in white participants but not in Black participants.

The study is the first to find a difference in the risk tied to low levels of HDL cholesterol between Black and white people. It also adds to accumulating evidence that a high level of HDL cholesterol isn’t necessarily helpful for one’s heart health. There appear to be other attributes of HDL that can be good. But researchers have also found that HDL’s role in health is complicated and ever-changing, with plenty to figure out.

The link between HDL and heart disease isn’t clear-cut

Cholesterol has long been explained as the “good?versus the “bad.?A high level of the “good?kind has been tied to a lower risk of cardiovascular disease, while having lots of the “bad?kind ?carried by low-density lipoprotein, or LDL, particles ?has been linked to a higher risk.

One of the big reports to bestow HDL cholesterol with the label of “good?came out of the Framingham Heart Study, a government-led effort launched in 1948 to investigate risk factors for cardiovascular disease. In 1977, Framingham researchers reported an inverse relationship between HDL cholesterol and coronary disease risk in a group made up of white participants.

But later studies undercut the premise that high levels are automatically good for heart health. People with a genetic mutation that boosts their HDL cholesterol level, for example, do not have lower risk of heart attacks than people without the mutation (SN: 5/18/12). And a class of drugs developed to increase HDL cholesterol did a great job upping numbers, but didn’t make a difference when it came to cardiovascular risk.

A person’s HDL cholesterol level is just one part of the story, though. Commonly reported on blood tests, the level reflects the amount of cholesterol that HDL particles have on board. HDL carries cholesterol away from the arteries to the liver to be excreted. This helps keep cholesterol from building up in artery walls, which can eventually impede blood flow. Recently, research on HDL has started looking beyond its cholesterol payload. “The big understanding over the last decade or so is that while you can measure the cholesterol, it doesn’t really reflect the actual functions that HDL is doing in the body,?says Anand Rohatgi, a cardiologist at the University of Texas Southwestern Medical Center in Dallas.

How well HDL removes cholesterol appears to matter. One measure of this job performance is HDL’s ability to receive cholesterol from a type of cell called a macrophage. In a U.S. study of close to 3,000 adults, 49 percent who were Black, the higher this capacity, the lower the incidence of heart attacks or strokes, Rohatgi and colleagues reported in the New England Journal of Medicine in 2014.

Ridding the body of cholesterol is just one of HDL’s many jobs. HDL also has anti-inflammatory and other protective effects that appear to guard against cardiovascular disease. But even these effects don’t always lead to a net good. In certain circumstances, HDL can become dysfunctional, such that its capacity to receive cholesterol is reduced, and it contributes to inflammation. The fact that HDL’s roles can change, depending on the context, has made studying HDL particles challenging, Rohatgi says.

How well HDL performs is still far from something that can be tested as part of a regular physical exam. It’s not clear “how to do it yet for the general public,?says Nathalie Pamir, a researcher who studies cardiology at the Oregon Health & Science University in Portland.

The impact of HDL cholesterol on heart health may differ by race

As researchers work toward a fuller understanding of HDL and how it might be better used as a clinical measure, the view of HDL cholesterol as uniformly “good?is still out there. And one’s HDL cholesterol level is still one entry in a widely used calculator that estimates cardiovascular risk. Pamir and her colleagues wanted to examine what high and low HDL cholesterol levels mean in a contemporary, diverse population. In the new study, the team analyzed data from the REGARDS trial, designed to study potential regional and racial differences in death from stroke in the United States. The study included nearly 24,000 participants ?of which 42 percent were Black ?who did not start out with coronary heart disease. Over roughly 10 years, 664 out of 10,095 Black participants and 951 out of 13,806 white participants had a heart attack or died from one. Increased levels of “bad?LDL cholesterol were tied to a higher risk of coronary heart disease, in line with past research, the team found. But for HDL cholesterol, high levels weren’t protective for anyone, and low levels were only predictive of higher risk in white people. That finding suggests it may be necessary to revisit how HDL cholesterol is used in the cardiovascular disease risk calculator, Pamir says.

Rather than just good, HDL cholesterol “is complicated,?she says. If a patient has high HDL cholesterol, a doctor “can say, ‘well, currently we don’t know what that means.’?/p> Although the study suggests that the impact of HDL cholesterol levels on disease risk may differ by race, it’s important to remember that race is a social construct, not a biological one, says Clyde Yancy, chief of cardiology at the Northwestern University Feinberg School of Medicine in Chicago.

Some of the risk factors for coronary heart disease, including high blood pressure and smoking, “are more prevalent in self-described Black Americans,?he says. And a community’s access to health care, nutritious food and opportunities for education and employment can influence those risk factors (SN: 5/15/17). “There is something unique about place and the history of place which may predispose to the burden of hypertension, obesity, even diabetes,?Yancy says.

It will take more research to understand what’s behind the potential race-based difference that the study reports, Yancy says, and what it means in terms of HDL cholesterol levels and cardiovascular disease risk. But it remains the case that high levels of LDL cholesterol ?which can accumulate in artery walls ?are associated with an increased risk, he says. “The LDL cholesterol seems to be our most relevant barometer.?/p>

For all that is known about what impacts cardiovascular disease risk, researchers still don’t have the full picture. The number of times that cardiologists see heart attacks in patients with normal cholesterol levels and normal blood pressure, Yancy says, suggests that, with current methods, “we’re not able to capture the entirety of the risk.?/p> ]]> Science News Thu, 12 Jan 2023 13:00:00 +0000 Astronomers using the James Webb Space Telescope have spotted “Green Pea?galaxies dating to 13.1 billion years ago. These viridescent runts, spotted just 700 million years after the Big Bang, might have helped trigger one of the greatest makeovers in cosmic history, astronomers said at a January 9 news conference in Seattle at the American Astronomical Society’s annual meeting.

Green Peas first showed up in 2009 in images from the Sloan Digital Sky Survey, an ambitious project to map much of the sky. Citizen science volunteers gave the objects their colorful name. Their greenish hue is because most of their light comes from glowing gas clouds, rather than directly from stars. These galaxies are rare in the present-day universe. Astronomers think that the ones that do exist are analogs of galaxies that were more plentiful in the early universe.

“They’re a bit like living fossils,?said astrophysicist James Rhoads of NASA’s Goddard Space Flight Center in Greenbelt, Md. “Coelacanths, if you will,?referencing a fish thought to be extinct until it showed up off the coast of South Africa in 1938 (SN: 12/2/11). 

These galaxies leak much more ultraviolet light, which can rip electrons from atoms, than typical galaxies do. So Green Peas dating to the universe’s first billion years or so could be partly responsible for a dramatic and mysterious cosmic transition called reionization, when most of the hydrogen atoms in the early universe had their electrons torn away (SN: 1/7/20).

Three ancient Green Peas turned up in JWST’s first image, released in July 2022 (SN: 7/21/22). The objects look red in JWST’s infrared vision, but the wavelengths of light they emit are like those of the previously discovered Green Peas. The findings were also published in the Jan. 1 Astrophysical Journal Letters.

“This helps us explain how the universe reionized,?Rhoads said. “I think this is an important piece of the puzzle.?/p> ]]> Science News Wed, 11 Jan 2023 16:00:00 +0000 As disappointing as that must have been, the bastnaesite still held value, and the prospectors sold their claim to the Molybdenum Corporation of America, later called Molycorp. The company was interested in mining the rare earths. During the mid-20th century, rare earth elements were becoming useful in a variety of ways: Cerium, for example, was the basis for a glass-polishing powder and europium lent luminescence to recently invented color television screens and fluorescent lamps.

For the next few decades, the site, later dubbed Mountain Pass mine, was the world’s top source for rare earth elements, until two pressures became too much. By the late 1980s, China was intensively mining its own rare earths ?and selling them at lower prices. And a series of toxic waste spills at Mountain Pass brought production at the struggling mine to a halt in 2002. But that wasn’t the end of the story. The green-tech revolution of the 21st century brought new attention to Mountain Pass, which later reopened and remains the only U.S. mine for rare earths. Rare earths are now integral to the manufacture of many carbon-neutral technologies ?plus a whole host of tools that move the modern world. These elements are the building blocks of small, super­efficient permanent magnets that keep smartphones buzzing, wind turbines spinning, electric vehicles zooming and more.

Mining U.S. sources of rare earth elements, President Joe Biden’s administration stated in February 2021, is a matter of national security.

Rare earths are not actually rare on Earth, but they tend to be scattered throughout the crust at low concentrations. And the ore alone is worth relatively little without the complex, often environmentally hazardous processing involved in converting the ore into a usable form, says Julie Klinger, a geographer at the University of Delaware in Newark. As a result, the rare earth mining industry is wrestling with a legacy of environmental problems. Rare earths are mined by digging vast open pits in the ground, which can contaminate the environment and disrupt ecosystems. When poorly regulated, mining can produce wastewater ponds filled with acids, heavy metals and radioactive material that might leak into groundwater. Processing the raw ore into a form useful to make magnets and other tech is a lengthy effort that takes large amounts of water and potentially toxic chemicals, and produces voluminous waste. “We need rare earth elements ?to help us with the transition to a climate-safe future,?says Michele Bustamante, a sustainability researcher at the Natural Resources Defense Council in Washington, D.C. Yet “everything that we do when we’re mining is impactful environmentally,?Bustamante says.

But there are ways to reduce mining’s footprint, says Thomas Lograsso, a metallurgist at the Ames National Laboratory in Iowa and the director of the Critical Materials Institute, a Department of Energy research center. Researchers are investigating everything from reducing the amount of waste produced during the ore processing to improving the efficiency of rare earth element separation, which can also cut down on the amount of toxic waste. Scientists are also testing alternatives to mining, such as recycling rare earths from old electronics or recovering them from coal waste.

Much of this research is in partnership with the mining industry, whose buy-in is key, Lograsso says. Mining companies have to be willing to invest in making changes. “We want to make sure that the science and innovations that we do are driven by industry needs, so that we’re not here developing solutions that nobody really wants,?he says.

Klinger says she’s cautiously optimistic that the rare earth mining industry can become less polluting and more sustainable, if such solutions are widely adopted. “A lot of gains come from the low-hanging fruit,?she says. Even basic hardware upgrades to improve insulation can reduce the fuel required to reach the high temperatures needed for some processing. “You do what you [can].?/p>

The environmental impact of rare earth mining

Between the jagged peaks of California’s Clark range and the Nevada border sits a broad, flat, shimmering valley known as the Ivanpah Dry Lake. Some 8,000 years ago, the valley held water year-round. Today, like many such playas in the Mojave Desert, the lake is ephemeral, winking into appearance only after an intense rain and flash flooding. It’s a beautiful, stark place, home to endangered desert tortoises and rare desert plants like Mojave milkweed. From about 1984 to 1998, the Ivanpah Dry Lake was also a holding pen for wastewater piped in from Mountain Pass. The wastewater was a by-product of chemical processing to concentrate the rare earth elements in the mined rock, making it more marketable to companies that could then extract those elements to make specific products. Via a buried pipeline, the mine sent wastewater to evaporation ponds about 23 kilometers away, in and around the dry lake bed. The pipeline repeatedly ruptured over the years. At least 60 separate spills dumped an estimated 2,000 metric tons of wastewater containing radioactive thorium into the valley. Federal officials feared that local residents and visitors to the nearby Mojave National Preserve might be at risk of exposure to that thorium, which could lead to increased risk of lung, pancreatic and other cancers. Unocal Corporation, which had acquired Molycorp in 1977, was ordered to clean up the spill in 1997, and the company paid over $1.4 million in fines and settlements. Chemical processing of the raw ore ground to a halt. Mining operations stopped shortly afterward. Half a world away, another environmental disaster was unfolding. The vast majority ?between 80 and 90 percent ?of rare earth elements on the market since the 1990s have come from China. One site alone, the massive Bayan Obo mine in Inner Mongolia, accounted for 45 percent of rare earth production in 2019. Bayan Obo spans some 4,800 hectares, about half the size of Florida’s Walt Disney World resort. It is also one of the most heavily polluted places on Earth. Clearing the land to dig for ore meant removing vegetation in an area already prone to desertification, allowing the Gobi Desert to creep southward. In 2010, officials in the nearby city of Baotou noted that radioactive, arsenic- and fluorine-containing mine waste, or tailings, was being dumped on farmland and into local water supplies, as well as into the nearby Yellow River. The air was polluted by fumes and toxic dust that reduced visibility. Residents complained of nausea, dizziness, migraines and arthritis. Some had skin lesions and discolored teeth, signs of prolonged exposure to arsenic; others exhibited signs of brittle bones, indications of skeletal fluorosis, Klinger says.
An aerial view of part of the Bayan Obo mine in China’s Inner Mongolia region
The Bayan Obo mine (shown) in China’s Inner Mongolia region was responsible for nearly half of the world’s rare earth production in 2019. Mining there has taken a heavy toll on the local residents and the environment.WU CHANGQING/VCG VIA GETTY IMAGES
The country’s rare earth industry was causing “severe damage to the ecological environment,?China’s State Council wrote in 2010. The release of heavy metals and other pollutants during mining led to “the destruction of vegetation and pollution of surface water, groundwater and farmland.?The “excessive rare earth mining,?the council wrote, led to landslides and clogged rivers. Faced with these mounting environmental disasters, as well as fears that it was depleting its rare earth resources too rapidly, China slashed its export of the elements in 2010 by 40 percent. The new limits sent prices soaring and kicked off concern around the globe that China had too tight of a stranglehold on these must-have elements. That, in turn, sparked investment in rare earth mining elsewhere.

In 2010, there were few other places mining rare earths, with only minimal production from India, Brazil and Malaysia. A new mine in remote Western Australia came online in 2011, owned by mining company Lynas. The company dug into fossilized lava preserved within an ancient volcano called Mount Weld.

Mount Weld didn’t have anywhere near the same sort of environmental impact seen in China: Its location was too remote and the mine was just a fraction of the size of Bayan Obo, according to Saleem Ali, an environmental planner at the University of Delaware. The United States, meanwhile, was eager to once again have its own source of rare earths ?and Mountain Pass was still the best prospect.

Mountain Pass mine gets revived

After the Ivanpah Dry Lake mess, the Mountain Pass mine changed hands again. Chevron purchased it in 2005, but did not resume operations. Then, in 2008, a newly formed company called Molycorp Minerals purchased the mine with ambitious plans to create a complete rare earth supply chain in the United States. The goal was not just mining and processing ore, but also separating out the desirable elements and even manufacturing them into magnets. Currently, the separations and magnet manufacturing are done overseas, mostly in China. The company also proposed a plan to avoid spilling wastewater into nearby fragile habitats. Molycorp resumed mining, and introduced a “dry tailings?process ?a method to squeeze 85 percent of the water out of its mine waste, forming a thick paste. The company would then store the immobilized, pasty residue in lined pits on its own land and recycle the water back into the facility.

Unfortunately, Molycorp “was an epic debacle?from a business perspective, says Matt Sloustcher, senior vice president of communications and policy at MP Materials, current owner of Mountain Pass mine. Mismanagement ultimately led Molycorp to file for Chapter 11 bankruptcy in 2015. MP Materials bought the mine in 2017 and resumed mining later that year. By 2022, Mountain Pass mine was producing 15 percent of the world’s rare earths.

MP Materials, too, has an ambitious agenda with plans to create a complete supply chain. And the company is determined not to repeat the mistakes of its predecessors. “We have a world-class ?unbelievable deposit, an untapped potential,?says Michael Rosenthal, MP Materials?chief operating officer. “We want to support a robust and diverse U.S. supply chain, be the magnetics champion in the U.S.?/p>

The challenges of separating rare earths

On a hot morning in August, Sloustcher stands at the edge of the Mountain Pass mine, a giant hole in the ground, 800 meters across and up to 183 meters deep, big enough to be visible from space. It’s an impressive sight, and a good vantage point from which to describe a vision for the future. He points out the various buildings: where the ore is crushed and ground, where the ground rocks are chemically treated to slough off as much non–rare earth material as possible, and where the water is squeezed from that waste and the waste is placed into lined ponds. The end result is a highly concentrated rare earth oxide ore ?still nowhere near the magnet-making stage. But the company has a three-stage plan “to restore the full rare earth supply to the United States,?from “mine to magnet,?Rosenthal says. Stage 1, begun in 2017, was to restart mining, crushing and concentrating the ore. Stage 2 will culminate in the chemical separation of the rare earth elements. And stage 3 will be magnet production, he says.

Since coming online in 2017, MP Materials has shipped its concentrated ore to China for the next steps, including the arduous, hazardous process of separating the elements from one another. But in November, the company announced to investors that it had begun the preliminary steps for stage 2, a “major milestone?/a> on the way to realizing its mine-to-magnet ambitions.

With investments from the U.S. Department of Defense, the company is building two separations facilities. One plant will pull out lighter rare earth elements ?those with smaller atomic numbers, including neodymium and praseodymium, both of which are key ingredients in the permanent magnets that power electric vehicles and many consumer electronics. MP Materials has additional grant money from the DOD to design and build a second processing plant to split apart the heavier rare earth elements such as dysprosium, also an ingredient in magnets, and yttrium, used to make superconductors and lasers.

Like stage 2, stage 3 is already under way. In 2022, the company broke ground in Fort Worth, Texas, for a facility to produce neodymium magnets. And it inked a deal with General Motors to supply those magnets for electric vehicle motors. But separating the elements comes with its own set of environmental concerns. The process is difficult and leads to lots of waste. Rare earth elements are extremely similar chemically, which means they tend to stick together. Forcing them apart requires multiple sequential steps and a variety of powerful solvents to separate them one by one. Caustic sodium hydroxide causes cerium to drop out of the mix, for example. Other steps involve solutions containing organic molecules called ligands, which have a powerful thirst for metal atoms. The ligands can selectively bind to particular rare earth elements and pull them out of the mix.

But one of the biggest issues plaguing this extraction process is its inefficiency, says Santa Jansone-Popova, an organic chemist at Oak Ridge National Laboratory in Tennessee. The scavenging of these metals is slow and imperfect, and companies have to go through a lot of extraction steps to get a sufficiently marketable amount of the elements. With the current chemical methods, “you need many, many, many stages in order to achieve the desired separation,?Jansone-Popova says. That makes the whole process “more complex, more expensive, and [it] produces more waste.?/p> Under the aegis of the DOE’s Critical Materials Institute, Jansone-Popova and her colleagues have been hunting for a way to make the process more efficient, eliminating many of those steps. In 2022, the researchers identified a ligand that they say is much more efficient at snagging certain rare earths than the ligands now used in the industry. Industry partners are on board to try out the new process this year, she says. In addition to concerns about heavy metals and other toxic materials in the waste, there are lingering worries about the potential impacts of radioactivity on human health. The trouble is that there is still only limited epidemiological evidence of the impact of rare earth mining on human and environmental health, according to Ali, and much of that evidence is related to the toxicity of heavy metals such as arsenic. It’s also not clear, he says, how much of the concerns over radioactive waste are scientifically supported, due to the low concentration of radioactive elements in mined rare earths. Such concerns get international attention, however. In 2019, protests erupted in Malaysia over what activists called “a mountain of toxic waste,?about 1.5 million metric tons, produced by a rare earth separation facility near the Malaysian city of Kuantan. The facility is owned by Lynas, which ships its rare earth ore from Australia’s Mount Weld to the site. To dissolve the rare earths, the ore is cooked with sulfuric acid and then diluted with water. The residue that’s left behind can contain traces of radioactive thorium.

A photo of machinery at a plant near Kuantan, Malaysia built by Australian company Lynas
Australian company Lynas built a plant near Kuantan, Malaysia, (shown in 2012) to separate and process the rare earth oxide ore mined at Mount Weld in Western Australia. Local protests erupted in 2019 over how the company disposes of its thorium-laced waste.GOH SENG CHONG/BLOOMBERG VIA GETTY IMAGES
Lynas had no permanent storage for the waste, piling it up in hills near Kuantan instead. But the alarm over the potential radioactivity in those hills may be exaggerated, experts say. Lynas reports that workers at the site are exposed to less than 1.05 millisieverts per year, far below the radiation exposure threshold for workers of 20 millisieverts set by the International Atomic Energy Agency.

“There’s a lot of misinformation about by­products such as thorium.?The thorium from rare earth processing is actually very low-level radiation,?Ali says. “As someone who has been a committed environmentalist, I feel right now that there’s not much science-based decision making on these things.?/p> Given the concerns over new mining, environmental think tanks like the World Resources Institute have been calling for more recycling of existing rare earth materials to reduce the need for new mining and processing.

“The path to the future has to do with getting the most out of what we take out of the ground,?says Bustamante, of the NRDC. “Ultimately the biggest lever for change is not in the mining itself, but in the manufacturing, and what we do with those materials at the end of life.?/p> That means using mined resources as efficiently as possible, but also recycling rare earths out of already existing materials. Getting more out of these materials can reduce the overall environmental impacts of the mining itself, she adds. That is a worthwhile goal, but recycling isn’t a silver bullet, Ali says. For one thing, there aren’t enough spent rare earth–laden batteries and other materials available at the moment for recycling. “Some mining will be necessary, [because] right now we don’t have the stock.?And that supply problem, he adds, will only grow as demand increases. ]]> Science News Wed, 11 Jan 2023 14:00:00 +0000 Sure, freezing to death is possible in frigid temperatures. But doctors and other health experts have long stressed that being cold won’t give you a cold. Still, winter is undisputedly cold-and-flu season. It’s also a period when COVID-19 spreads more.

But if the chill doesn’t matter, why does the spread of so many respiratory viruses peak during the season?

“I’ve spent the past 13 years looking into this question,?says Linsey Marr, a civil and environmental engineer at Virginia Tech in Blacksburg who studies viruses in the air. “The deeper we go, the more I realize we don’t know [and] the more there is to figure out.?/p> She and I are not alone. “That wintertime seasonality has puzzled people for a very long time; thousands of years, to be honest,?says Jeffrey Shaman, an infectious diseases researcher who directs the Climate and Health Program at the Columbia University Mailman School of Public Health. There is some evidence that winter’s shorter days may make people more susceptible to infection, he says. Less sunlight means people make less vitamin D, which is required for some immune responses. But that’s just one piece of the puzzle. Scientists are also looking at what other factors may play a role in making winter a sickening season.

Illness may spread more inside.

My grandma’s well-intentioned urging to come in from the cold may have instead increased the risk that I’d get sick.

Colds, influenza and respiratory syncytial virus, or RSV, are all illnesses that are more prevalent at certain times of year when people spend more time inside. That includes winter in temperate climates, where there are distinct seasons, and rainy seasons in tropical zones. COVID-19 also spreads more indoors than outside (SN: 6/18/20).

Those diseases are caused by viruses that are transmitted primarily through breathing in small droplets known as aerosols. That’s a change in thinking. Many scientists thought until very recently that such viruses were spread mainly by touching contaminated surfaces (SN: 12/16/21).

“When you’re outdoors, you’re in the ultimate well-ventilated space,?says David Fisman, an epidemiologist at the University of Toronto Dalla Lana School of Public Health. Viruses exhaled outside are diluted quickly with clean air. But inside, aerosols and the viruses they contain can build up. “When you’re in a poorly ventilated space, the air you breathe in is often air that other people have breathed out,?he says. Since viruses come along with that exhaled breath, “it makes a lot of sense that proximity to individuals who might be contagious would facilitate transmission,?Shaman says. But there is more to the story, says Benjamin Bleier, a specialist for sinus and nasal disorders at Harvard Medical School. “In modern society, we’re indoors all year round,?he says. To drive the seasonal pattern we see year after year, something else must be going on too to make people more susceptible to infection and increase the amount of virus circulating, he says.

Drier air can give some viruses a boost.

Some viruses thrive in winter. But the reason why may not be so much about temperature, but humidity. “There are some viruses that like it warm and wet, and some viruses like it dry and cold,?says Donald Milton, an aerobiologist at the University of Maryland School of Public Health in College Park. For instance, rhinoviruses ?one of the many types of viruses that cause colds ?survive better when it is humid. Cases of rhinovirus infection typically peak in early fall, he says. Marr and other researchers have found that viruses that surge in the winter, including influenza viruses and SARS-CoV-2 ?the coronavirus that causes COVID-19 ?survive best when the relative humidity in the air falls below about 40 percent. Viruses aren’t usually floating around naked, Marr says. They are encased in droplets of fluid, such as saliva. Those droplets also have bits of mucus, proteins, salt and other substances in them. Those other components may determine if the virus survives drying.

When the humidity is higher, droplets dry slowly. Such slow drying kills viruses such as influenza A and SARS-CoV-2, Marr and colleagues reported July 27 in a preprint at During slow drying, salt and other things that may harm the virus become more concentrated, although researchers still don’t fully understand what’s happening at the molecular scale to inactivate the virus.

But flash drying in parched air preserves those viruses. “If the air is very dry, the water quickly evaporates. Everything is dried down, and it’s almost like things are frozen in place,?Marr says. Dryer, smaller aerosols are also more buoyant and may hang in the air longer, increasing the chance that someone will breathe them in, Fisman says.

What’s more, dry air can tear down some of people’s defenses against viruses. Studies in animals suggest that dry air can trigger death of some cells lining the airways. That could leave cracks where viruses can invade.

Mucus in the airways can trap viruses and help protect against infection. But breathing cold, dry air can also slow the system that usually moves mucus out of the body. That may give viruses time to break out of the mucus trap and invade cells, Fisman says.

Cold may harm our ability to fight off viruses.

Being cold may not give you a cold, but it could make you more susceptible to catching one. Normally, the immune system has a trick for warding off viruses, Bleier and colleagues recently discovered. Cells in the nose and elsewhere in the body are studded with surface proteins that can detect viruses. When one of these sensor proteins sees a virus coming, it signals the cell to release tiny bubbles called extracellular vesicles. The bubbles work as a diversionary tactic, a bit like chaff being released from a military jet trying to avoid a heat-seeking missile, Bleier says. Viruses may go after the vesicles instead of infecting cells.

If a virus docks with one of the bubbles, it’s in for a surprise: Inside the vesicles are virus-killing bits of RNA called microRNAs. One of those microRNAs known as miR-17 could kill two types of rhinoviruses and a cold-causing coronavirus, the team reported December 6 in the Journal of Allergy and Clinical Immunology.

Researchers measured bubbles released from human nasal cells grown in lab dishes at 37° Celsius, our typical body temperature. Then the scientists lowered the thermostat to 32° C.  Cells released about 42 percent fewer vesicles at the cooler temperature, the team found. What’s more, those vesicles carried fewer weapons. Vesicles can pack in about 24 percent more microRNA at body temperature than when it is cooler.

Three tips to bolster our immune system.

I asked the experts what people can do to protect themselves from viruses in the winter. Some said using a humidifier might help raise moisture levels enough to slow the drying of virus-laden droplets, killing the viruses.

“Any increase in humidity should be beneficial,?says Shaman. “You get a lot of bang for your buck if you go from very dry to dry.?/p> But Milton doesn’t think it’s a good idea to pump a lot of moisture into a house when it is cold outside. “That humidity is going to find all of the cold spaces in your house and condense there,?creating a breeding ground for mold and rot, he says.

Instead, he advocates turning on kitchen and bathroom exhaust fans to increase ventilation and to use HEPA filters or Corsi-Rosenthal boxes to filter unwanted viruses out of the air (SN: 7/25/22).

Bleier suggests wearing a mask. Not only can masks filter out viruses, but “our work suggests these masks have a second mechanism of action,?he says. “They keep a cushion of warm [moist] air in front of our noses, which could help bolster the immune system.?/p> ]]> Science News Wed, 11 Jan 2023 12:00:00 +0000 SEATTLE ?Attention alien hunters: If you want to find life on distant planets, try looking for signs of toxic chemical cleanup. 

Gases that organisms produce as they tidy up their environments could provide clear signs of life on planets orbiting other stars, researchers announced January 9 at the American Astronomical Society meeting. All we need to do to find hints of alien life is to look for those gases in the atmospheres of those exoplanets, in images coming from the James Webb Space Telescope or other observatories that could come online soon.

Barring an interstellar radio broadcast, the chemistry of a remote planet is one of the more promising ways that researchers could detect extraterrestrial life. On Earth, life produces lots of chemicals that alter the atmosphere: Plants churn out oxygen, for example, and a host of animals and plants release methane. Life elsewhere in the galaxy might do the same thing, leaving a chemical signature humans could detect from afar (SN: 9/30/21).

But many of life’s gases are also released in processes that have nothing to do with life at all. Their detection could lead to the false impression of a living planet in a faraway solar system, when it’s really just a sterile rock. At least one type of compound that some organisms produce to protect themselves from toxic elements, however, might provide unambiguous indications of life. The life-affirming compounds are called methylated gases. Microbes, fungi, algae and plants are among the terrestrial organisms that create the chemicals by linking carbon and hydrogen atoms to toxic materials such as chlorine or bromine. The resulting compounds evaporate, sweeping the deadly elements away. The fact that living creatures almost always have a hand in making methylated gases means the presence of the compounds in a planet’s atmosphere would be a strong sign of life of some kind, planetary astrobiologist Michaela Leung of the University of California, Riverside said at the meeting. The same isn’t true of oxygen and methane. Oxygen, in particular, can accumulate when a hot star warms a planet’s oceans. “You have a steam atmosphere, and the [ultraviolet] radiation from the star splits up the water?into its constituent parts, oxygen and hydrogen, Leung says. Hydrogen is light, so much of it is lost to space on small planets. “What you have left is all of this oxygen,?which, she says, leads to “really convincing oxygen signals in this process that at no point involved life.? Similarly, while living organisms produce methane in abundance, lifeless geological phenomena like volcanoes do too.

At the concentrations of methylated gases typical of Earth, these gases will be hard to see in the atmospheres of distant planets, even with an instrument as powerful as the Webb telescope (SN: 12/20/22). But Leung has reason to believe there may be planets where the gas abundance is thousands of times that of Earth.

“The most productive environments [for releasing methylated gases] that we see here on Earth,?she says, “are things like estuaries and wetlands.?A watery planet with lots of small continents and correspondingly more coastline, for example, could be packed with organisms cleaning away toxic chemicals with methylated gases. One of the benefits of looking for the compounds as a sign of life is that it doesn’t require that the life resembles anything like what we have on our planet. “Maybe it’s not DNA-based, maybe it has other weird chemistry going on,?Leung says. But by assuming chlorine and bromine are likely to be toxic generally, methylated gases offer what Leung calls an agnostic biosignature, which can tell us that something is alive on a planet even if it’s utterly alien to us.

“The more signs of life we know to look for, then the better our chances of recognizing life when we do encounter it,?says Vikki Meadows, an astrobiologist at the University of Washington in Seattle who was not involved with the study. “It also helps us understand what kind of telescopes we should build, what we should look for and what the instrument requirements should be. Michaela’s work is really important for that reason.?/p> ]]>