Want a ‘Shrinky Dinks’ approach to nano-sized devices? Try hydrogels

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.
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.”

Too much of this bacteria in the nose may worsen 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.
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.”

Chicken DNA is replacing the genetics of their ancestral jungle fowl

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.

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.”

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.

A bird with a T. rex head may help reveal how dinosaurs became birds

A 120-million-year-old fossil bird found in China could offer some new clues about how landbound dinosaurs evolved into today’s flying birds. The dove-sized Cratonavis zhui sported a dinosaur-like head atop a body similar to those of today’s birds, researchers report in the January Nature Ecology & Evolution.

The flattened specimen came from the Jiufotang Formation, an ancient body of rock in northeastern China that is a hotbed for preserved feathered dinosaurs and archaic birds. CT scans revealed that Cratonavis had a skull that was nearly identical (albeit smaller) as those of theropod dinosaurs like Tyrannosaurus rex, paleontologist Li Zhiheng of the Chinese Academy of Sciences in Beijing and colleagues report. This means that Cratonavis still hadn’t evolved the mobile upper jaw found in modern birds (SN: 5/2/18).
It’s among just a handful of specimens that belong to a recently identified group of intermediate birds known as the jinguofortisids, says Luis Chiappe, a paleontologist at the Natural History Museum of Los Angeles County who was not involved in the study. Its dino-bird mishmash “is not unexpected.” Most birds discovered from the Age of Dinosaurs exhibited more primitive, toothed heads than today’s birds, he says. But the new find “builds on our understanding of this primitive group of birds that are at the base of the tree of birds.”

Cratonavis also had an unusually elongated scapula and hallux, or backward-facing toe. Rarely seen in Cretaceous birds, enlarged shoulder blades might have compensated for the bird’s otherwise underwhelming flight mechanics, the researchers say. And that hefty big toe? It bucks the trend of shrinking metatarsals seen as birds continued to evolve. Cratonavis might have used this impressive digit to hunt like today’s birds of prey, Li’s team says.

Filling those shoes may have been too big of a job for Cratonavis, though. Given its size, Chiappe says, the dino-headed bird would have most likely been a petite hunter, taking down the likes of beetles, grasshoppers and the occasional lizard rather than terrorizing the skies.

Lots of Tatooine-like planets around binary stars may be habitable

SEATTLE — Luke Skywalker’s home planet in Star Wars is the stuff of science fiction. But Tatooine-like planets in orbit around pairs of stars might be our best bet in the search for habitable planets beyond our solar system.

Many stars in the universe come in pairs. And lots of those should have planets orbiting them (SN: 10/25/21). That means there could be many more planets orbiting around binaries than around solitary stars like ours. But until now, no one had a clear idea about whether those planets’ environments could be conducive to life. New computer simulations suggest that, in many cases, life could imitate art.
Earthlike planets orbiting some configurations of binary stars can stay in stable orbits for at least a billion years, researchers reported January 11 at the American Astronomical Society meeting. That sort of stability, the researchers propose, would be enough to potentially allow life to develop, provided the planets aren’t too hot or cold.

Of the planets that stuck around, about 15 percent stayed in their habitable zone — a temperate region around their stars where water could stay liquid — most or even all of the time.

The researchers ran simulations of 4,000 configurations of binary stars, each with an Earthlike planet in orbit around them. The team varied things like the relative masses of the stars, the sizes and shapes of the stars’ orbits around each other, and the size of the planet’s orbit around the binary pair.

The scientists then tracked the motion of the planets for up to a billion years of simulated time to see if the planets would stay in orbit over the sorts of timescales that might allow life to emerge.

A planet orbiting binary stars can get kicked out of the star system due to complicated interactions between the planet and stars. In the new study, the researchers found that, for planets with large orbits around star pairs, only about 1 out of 8 were kicked out of the system. The rest were stable enough to continue to orbit for the full billion years. About 1 in 10 settled in their habitable zones and stayed there.

Of the 4,000 planets that the team simulated, roughly 500 maintained stable orbits that kept them in their habitable zones at least 80 percent of the time.

“The habitable zone . . . as I’ve characterized it so far, spans from freezing to boiling,” said Michael Pedowitz, an undergraduate student at the College of New Jersey in Ewing who presented the research. Their definition is overly strict, he said, because they chose to model Earthlike planets without atmospheres or oceans. That’s simpler to simulate, but it also allows temperatures to fluctuate wildly on a planet as it orbits.
“An atmosphere and oceans would smooth over temperature variations fairly well,” says study coauthor Mariah MacDonald, an astrobiologist also at the College of New Jersey. An abundance of air and water would potentially allow a planet to maintain habitable conditions, even if it spent more of its time outside of the nominal habitable zone around a binary star system.

The number of potentially habitable planets “will increase once we add atmospheres,” MacDonald says, “but I can’t yet say by how much.”

She and Pedowitz hope to build more sophisticated models in the coming months, as well as extend their simulations beyond a billion years and include changes in the stars that can affect conditions in a solar system as it ages.

The possibility of stable and habitable planets in binary star systems is a timely issue says Penn State astrophysicist Jason Wright, who was not involved in the study.

“At the time Star Wars came out,” he says, “we didn’t know of any planets outside the solar system, and wouldn’t for 15 years. Now we know that there are many and that they orbit these binary stars.”

These simulations of planets orbiting binaries could serve as a guide for future experiments, Wright says. “This is an under-explored population of planets. There’s no reason we can’t go after them, and studies like this are presumably showing us that it’s worthwhile to try.”

Procrastination may harm your health. Here’s what you can do

The worst procrastinators probably won’t be able to read this story. It’ll remind them of what they’re trying to avoid, psychologist Piers Steel says.

Maybe they’re dragging their feet going to the gym. Maybe they haven’t gotten around to their New Year’s resolutions. Maybe they’re waiting just one more day to study for that test.

Procrastination is “putting off to later what you know you should be doing now,” even if you’ll be worse off, says Steel, of the University of Calgary in Canada. But all those tasks pushed to tomorrow seem to wedge themselves into the mind — and it may be harming people’s health.
In a study of thousands of university students, scientists linked procrastination to a panoply of poor outcomes, including depression, anxiety and even disabling arm pain. “I was surprised when I saw that one,” says Fred Johansson, a clinical psychologist at Sophiahemmet University in Stockholm. His team reported the results January 4 in JAMA Network Open.

The study is one of the largest yet to tackle procrastination’s ties to health. Its results echo findings from earlier studies that have gone largely ignored, says Fuschia Sirois, a behavioral scientist at Durham University in England, who was not involved with the new research.

For years, scientists didn’t seem to view procrastination as something serious, she says. The new study could change that. “It’s that kind of big splash that’s … going to get attention,” Sirois says. “I’m hoping that it will raise awareness of the physical health consequences of procrastination.”

Procrastinating may be bad for the mind and body
Whether procrastination harms health can seem like a chicken-and-egg situation.

It can be hard to tell if certain health problems make people more likely to procrastinate — or the other way around, Johansson says. (It may be a bit of both.) And controlled experiments on procrastination aren’t easy to do: You can’t just tell a study participant to become a procrastinator and wait and see if their health changes, he says.
Many previous studies have relied on self-reported surveys taken at a single time point. But a snapshot of someone makes it tricky to untangle cause and effect. Instead, in the new study, about 3,500 students were followed over nine months, so researchers could track whether procrastinating students later developed health issues.

On average, these students tended to fare worse over time than their prompter peers. They were slightly more stressed, anxious, depressed and sleep-deprived, among other issues, Johansson and colleagues found. “People who score higher on procrastination to begin with … are at greater risk of developing both physical and psychological problems later on,” says study coauthor Alexander Rozental, a clinical psychologist at Uppsala University in Sweden. “There is a relationship between procrastination at one time point and having these negative outcomes at the later point.”

The study was observational, so the team can’t say for sure that procrastination causes poor health. But results from other researchers also seem to point in this direction. A 2021 study tied procrastinating at bedtime to depression. And a 2015 study from Sirois’ lab linked procrastinating to poor heart health.

Stress may be to blame for procrastination’s ill effects, data from Sirois’ lab and other studies suggest. She thinks that the effects of chronic procrastinating could build up over time. And though procrastination alone may not cause disease, Sirois says, it could be “one extra factor that can tip the scales.”

No, procrastinators are not lazy
Some 20 percent of adults are estimated to be chronic procrastinators. Everyone might put off a task or two, but chronic procrastinators make it their lifestyle, says Joseph Ferrari, a psychologist at DePaul University in Chicago, who has been studying procrastination for decades. “They do it at home, at school, at work and in their relationships.” These are the people, he says, who “you know are going to RSVP late.”

Though procrastinators may think they perform better under pressure, Ferrari has reported the opposite. They actually worked more slowly and made more errors than non-procrastinators, his experiments have shown. And when deadlines are slippery, procrastinators tend to let their work slide, Steel’s team reported last year in Frontiers in Psychology.

For years, researchers have focused on the personalities of people who procrastinate. Findings vary, but some scientists suggest procrastinators may be impulsive, worriers and have trouble regulating their emotions. One thing procrastinators are not, Ferrari emphasizes, is lazy. They’re actually “very busy doing other things than what they’re supposed to be doing,” he says.

In fact, Rozental adds, most research today suggests procrastination is a behavioral pattern.

And if procrastination is a behavior, he says, that means it’s something you can change, regardless of whether you’re impulsive.

Why procrastinators should be kind to themselves
When people put off a tough task, they feel good — in the moment.
Procrastinating is a way to sidestep the negative emotions linked to the task, Sirois says. “We’re sort of hardwired to avoid anything painful or difficult,” she says. “When you procrastinate, you get immediate relief.” A backdrop of stressful circumstances — say, a worldwide pandemic — can strain people’s ability to cope, making procrastinating even easier. But the relief it provides is only temporary, and many seek out ways to stop dawdling.

Researchers have experimented with procrastination treatments that run the gamut from the logistical to the psychological. What works best is still under investigation. Some scientists have reported success with time-management interventions. But the evidence for that “is all over the map,” Sirois says. That’s because “poor time management is a symptom not a cause of procrastination,” she adds.

For some procrastinators, seemingly obvious tips can work. In his clinical practice, Rozental advises students to simply put down their smartphones. Silencing notifications or studying in the library rather than at home can quash distractions and keep people on task. But that won’t be enough for many people, he says.

Hard-core procrastinators may benefit from cognitive behavioral therapy. In a 2018 review of procrastination treatments, Rozental found that this type of therapy, which involves managing thoughts and emotions and trying to change behavior, seemed to be the most helpful. Still, not many studies have examined treatments, and there’s room for improvement, he says.

Sirois also favors an emotion-centered approach. Procrastinators can fall into a shame spiral where they feel uneasy about a task, put the task off, feel ashamed for putting it off and then feel even worse than when they started. People need to short-circuit that loop, she says. Self-forgiveness may help, scientists suggested in one 2020 study. So could mindfulness training.

In a small trial of university students, eight weekly mindfulness sessions reduced procrastination, Sirois and colleagues reported in the January Learning and Individual Differences. Students practiced focusing on the body, meditating during unpleasant activities and discussed the best way to take care of themselves. A little self-compassion may snap people out of their spiral, Sirois says.

“You made a mistake and procrastinated. It’s not the end of the world,” she says. “What can you do to move forward?”