These Chinese zodiac animals etched in hydrogels come in many materials, including gold (goat), titanium dioxide (snake) and luminescent nanoparticles (rabbit). The images on the bottom are each a few dozen micrometers wide. The images at the top started that big and were then shrunk to roughly one-tenth their size.
The Chinese University of Hong Kong, Carnegie Mellon University
High-tech shrink art may be the key to making tiny electronics, 3-D nanostructures or even holograms for hiding secret messages.
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.
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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.
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.”
James Riordon is a freelance science writer who covers physics, math, astronomy and occasional lifestyle stories.
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There’s a lot more of the bacterial species Streptococcus salivarius (shown) in the noses of people with hay fever than the noses of those without, researchers have found. The overabundance may be exacerbating allergy symptoms.
A type of bacteria that’s overabundant in the nasal passages of people with hay fever may worsen symptoms. Targeting that bacteria may provide a way to rein in ever-running noses.
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 .
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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’ 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.”
Aimee Cunningham is the biomedical writer. She has a master’s degree in science journalism from New York University.
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The lights of San Francisco scatter and reflect off the city’s famous fog, making the sky bright even at night. Even above fog-free cities, skies are growing brighter at a faster clip than previously thought.
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.
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“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.”
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.”
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.
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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.
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.”
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.”
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.”
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 ’70s, 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.
Lisa Grossman is the astronomy writer. She has a degree in astronomy from Cornell University and a graduate certificate in science writing from University of California, Santa Cruz. She lives near Boston.
Our mission is to provide accurate, engaging news of science to the public. That mission has never been more important than it is today.
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Today’s red jungle fowl — the wild forebears of the domesticated chicken — are becoming more chickenlike. New research suggests that a large proportion of the wild fowl’s DNA has been inherited from chickens, and relatively recently.
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 ).
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“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 .
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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.”
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.
Jake Buehler is a freelance science writer, covering natural history, wildlife conservation and Earth’s splendid biodiversity, from salamanders to sequoias. He has a master’s degree in zoology from the University of Hawaii at Manoa.
Our mission is to provide accurate, engaging news of science to the public. That mission has never been more important than it is today.
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Science News was founded in 1921 as an independent, nonprofit source of accurate information on the latest news of science, medicine and technology. Today, our mission remains the same: to empower people to evaluate the news and the world around them. It is published by the Society for Science, a nonprofit 501(c)(3) membership organization dedicated to public engagement in scientific research and education (EIN 53-0196483).
Specially tailored laser beams can create a channel in the air through which light can efficiently travel, creating something akin to a fiber optic cable made of air.
Tubular laser beams can create what amount to fiber-optic cables made of thin air , researchers report in a study to appear in Physical Review X .
Laser-heated air can efficiently transmit light signals without the need to lay fiber-optic cables. These air-based “waveguides” can also provide pathways for ultrahigh-energy lasers that don’t propagate well through air on their own, building on earlier efforts that have been touted as a route to laser beam weapons ( SN: 3/5/14 ).
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The latest experiments, says physicist Howard Milchberg of the University of Maryland in College Park, beat out his team’s prior waveguide attempts by more than 60 times, extending the length of a waveguide to nearly 50 meters.
The researchers ran a laser in “doughnut mode,” where the beam has a hollowed-out core along its length, resembling a stack of luminous doughnuts. The beam creates a hot, tubular air layer wrapped around cooler, denser air. This creates something akin to a fiber-optic cable made of air: Instead of a transparent core covered in plastic cladding that guides light in conventional fiber optics, the dense air acts as the core, while the hot air around it serves as cladding.
Stepping up the waveguide length to kilometers, Milchberg says, is primarily a matter of boosting the doughnut-mode laser power. “The only issue is we don’t have a kilometer” to safely fire a laser that far, he says. It may take a deal with one of the U.S. national laboratories to find space to run a longer version of the experiment.
Despite the potential military applications, Milchberg says he and his team are focused more on scientific uses, such as extending the range of systems that reveal the chemical makeup of materials by firing lasers at them and measuring the light they give off. Air-based waveguides could send emitted light back to remotely located systems, instead of needing to get up close to analyze a sample.
James Riordon is a freelance science writer who covers physics, math, astronomy and occasional lifestyle stories.
Our mission is to provide accurate, engaging news of science to the public. That mission has never been more important than it is today.
As a nonprofit news organization, we cannot do it without you.
Your support enables us to keep our content free and accessible to the next generation of scientists and engineers. Invest in quality science journalism by donating today.
Science News was founded in 1921 as an independent, nonprofit source of accurate information on the latest news of science, medicine and technology. Today, our mission remains the same: to empower people to evaluate the news and the world around them. It is published by the Society for Science, a nonprofit 501(c)(3) membership organization dedicated to public engagement in scientific research and education (EIN 53-0196483).
Analyses of tin ingots found aboard a merchant ship that sank off Turkey’s coast around 3,300 years ago suggest that sophisticated supply chains of the metal ran from Central Asia and part of Turkey to the Mediterranean. A replica of the vessel is shown.
Long-distance supply chains, vulnerable to disruptions from wars and disease outbreaks, may have formed millennia before anyone today gasped at gas prices or gawked at empty store shelves.
Roughly 3,650 to 3,200 years ago, herders and villagers who mined tin ore fueled long-distance supply chains that transported the metal from Central Asia and southern Turkey to merchant ships serving societies clustered around the Mediterranean, a new study finds.
Remote communities located near rare tin deposits tapped into an intense demand among ancient urban civilizations for a metal that, along with copper, was needed to produce bronze, researchers report in the Dec. 2 Science Advances .
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Tin access transformed herders and part-time cultivators into powerful partners of Late Bronze Age states and rulers, say archaeometallurgist Wayne Powell of Brooklyn College in New York City and colleagues. Until now, it has been difficult to demonstrate the existence of such an ancient, long-distance tin supply chain or its geographic origins.
Powell’s group builds their argument on previous archaeological evidence that mobile groups in Central Asia spread crop cultivation across much of Asia more than 4,000 years ago ( SN: 4/2/14 ) and pioneered popular clothes-making innovations by 3,000 years ago ( SN: 2/18/22 ). Land routes used by those groups would have connected Central Asian tin ore sources to the Mediterranean, the researchers say.
Evidence of an ancient tin pipeline stretching more than 3,000 kilometers from mining sites in present-day Tajikistan and Uzbekistan to merchant ships carrying processed tin in the eastern Mediterranean is particularly striking, says anthropologist Michael Frachetti of Washington University in St. Louis.
“That complex tin network was an early version of modern-day supply chains for commodities such as gas and oil,” Frachetti says.
Writing on clay tablets from Bronze Age sites in what’s now Turkey and Iraq refers to tin arriving from far to the east as early as around 3,900 years ago. But precise sources for eastern tin have proved elusive.
An ancient shipwreck discovered in 1982 off Turkey’s coast enabled the new study. Known as the Uluburun shipwreck, the vessel dates to around 3,300 years ago and is one of the oldest known shipwrecks. Its cargo included one metric ton of tin. The metal had been cast into portable, distinctively shaped pieces called ingots.
Powell’s group documented chemical fingerprints of 105 tin ingots, nearly all of those found in the Uluburun shipwreck. Ingot IDs were based on distinct combinations of different forms, or isotopes, of tin, lead and trace elements in the ingots. Data on the isotopic profiles of tin ore deposits in different parts of Eurasia have become available over the last few years, allowing the researchers to match the ingots’ tin to deposits, Powell says.
Powell, Frachetti and colleagues traced the origins of about one-third of the Uluburun tin ingots to an ore deposit in Tajikistan and several others nearby in Uzbekistan. Previous excavations indicate that herding groups used stone hammers to mine tin from outcrops at those sites.
Most of the remaining shipwreck ingots were linked to small tin deposits in southeastern Turkey’s Taurus Mountains. Mountain communities controlled by the ancient Hittite kingdom probably collected tin from those deposits, Frachetti says ( SN: 5/1/18 ). Until now, many researchers have assumed that Turkish tin sources were depleted by the Late Bronze Age.
Despite the new evidence, geographic origins of the Uluburun tin ingots remain unclear, says archaeometallurgist Daniel Berger of Curt-Engelhorn-Centre of Archaeometry in Mannheim, Germany. Berger, who studies Bronze Age tin sources with another research group, did not participate in the new study.
Tin ores typically contain low lead levels, but the shipwreck ingots display high levels. Lead was probably added, deliberately or via accidental contamination, to tin somewhere on its way to the Mediterranean, he suggests. If so, that potentially complicates the attempt by Powell’s group to combine tin and lead isotopes to identify tin sources.
Isotopic signatures of tin within the same ore deposits vary greatly, and overlap exists between different deposits, Berger says. So tin isotopes by themselves cannot definitively identify tin sources of the Uluburun ingots.
“Tracing the tin sources of the Bronze Age is and remains one of the most challenging problems in archaeology,” Berger says. Efforts to identify chemical and molecular properties of different Eurasian tin deposits are still in the early stages, he adds.
Bruce Bower has written about the behavioral sciences for Science News since 1984. He writes about psychology, anthropology, archaeology and mental health issues.
Our mission is to provide accurate, engaging news of science to the public. That mission has never been more important than it is today.
As a nonprofit news organization, we cannot do it without you.
Your support enables us to keep our content free and accessible to the next generation of scientists and engineers. Invest in quality science journalism by donating today.
Science News was founded in 1921 as an independent, nonprofit source of accurate information on the latest news of science, medicine and technology. Today, our mission remains the same: to empower people to evaluate the news and the world around them. It is published by the Society for Science, a nonprofit 501(c)(3) membership organization dedicated to public engagement in scientific research and education (EIN 53-0196483).
