After some polar sleuthing, which involved scrutiny of hair collected from six polar bears in the wild, the scientists homed in on the hair “sebum” (or grease) as the all-important protectant. This sebum, which is made up of cholesterol, diacylglycerols, and fatty acids, makes it very hard for ice to attach to their fur.

While this finding sheds fascinating new light on our understanding of polar bear — and even Inuit — ecology, it may also have a suite of unrelated applications, with a similar concoction of artificially made sebum promising to be useful as an anti-ice surface coating, or in next-gen ski skins used by skiers and snowboarders.

Julian Carolan, PhD Candidate from Trinity College Dublin’s School of Chemistry and the AMBER Research Ireland Centre, is the first author of the journal article, which has been published today as the cover story in leading international journal Science Advances.

He said: “We measured ice adhesion strength, which is a useful measure of how well ice sticks to fur; hydrophobicity, which dictates whether water can be shed before it freezes; and freezing delay time, which simply shows how long it takes for a drop of water to freeze at certain temperatures on a given surface. We then compared the performance of the polar bear hair with that of human hair and two types of specialist human-made ‘ski skins’.

“The sebum quickly jumped out as being the key component giving this anti-icing effect as we discovered the adhesion strength was greatly impacted when the hair was washed. Unwashed, greasy hair made it much harder for ice to stick. In contrast when the polar bear hair was washed and the grease largely removed it performed similarly to human hair, to which ice sticks easily whether it is washed or greasy.”

That finding led the team to perform a detailed chemical analysis of polar bear sebum. As well as identifying the key components (cholesterol, diacylglycerols, and fatty acids), they were surprised to find “squalene” was absent. This fatty metabolite is present in human hair, and in the hair of other aquatic animals, like sea otters, which suggests its absence in polar bear hair is very important from an anti-icing perspective.

Dr Richard Hobbs, Assistant Professor and Royal Society-Science Foundation Ireland University Research Fellow in Trinity’s School of Chemistry and the AMBER Research Ireland Centre, is a senior author of the journal article. He added: “Animals living in polar habitats have emerged as a source of inspiration for the development of new anti-icing materials.

“For example, Anne Kietzig’s group at McGill recently found that the hierarchical structure of Gentoo penguin feathers afforded them anti-icing properties that relied on the feather structure rather than the preen oil coating. Our work shows that polar bear fur provides an alternative strategy to produce an anti-icing surface based on the characteristic blend of lipids present in their fur sebum or hair grease.

“This work not only represents the first study of the composition of polar bear fur sebum, but it also resolves the question of why polar bears don’t suffer from ice accumulation. Despite having thick layers of insulating blubber and fur, and spending extensive periods in water at sub-zero temperatures, it seems that the fur grease provides a natural route for polar bears to easily shed ice when it forms due to the low ice adhesion on their fur.

“We expect that these natural lipid coatings produced by the bear will help us to develop new more sustainable anti-icing coatings that may replace problematic ‘forever chemicals’ like PFAS that have been used as anti-icing coatings.”

In addition to the structural explanations, these interesting discoveries also help us better understand hunting behaviours — both of polar bears and of native Inuit populations.

Prof. Bodil Holst, University of Bergen, is a senior author of the journal article. She added: “One of the polar bears’ main hunting strategies is ‘still hunting’, where they lay motionless beside a breathing hole on sea ice waiting for seals to surface. Still hunting frequently develops into an ‘aquatic stalk’ with the polar bear using its hind paws to slide into the water to pursue its prey, and the lower the ice adhesion, the less noise generated and the faster and quieter the slide.

“Our findings also help us understand the subtlety of the steps taken by Inuit people to optimise hunting strategies to mimic the polar bear method of still hunting. Inuit hunting stools are sometimes shod with polar bear fur on the feet to avoid noise when moving on the ice, while people also sometimes wear ‘polar bear trousers’, ensuring the entire contact area with the ice is covered in low ice-adhesion polar bear fur for optimal noise reduction.”

Notably, the traditional Inuit preparation method protects the sebum on the fur by ensuring the hair-covered side of the skin is not washed. This is unlike, for example, a fox skin, which would traditionally be cleaned by rubbing the hair side with soapstone or dry clay.

A team of researchers led by Celia Romero, a graduate student in clinical psychology, along with associate professor Lynn Perry, professor Michael Alessandri, and former University professor Lucina Uddin, explored the role of bilingualism in 112 children, including typically developing children and children with autism, between the ages of 7 to 12 years old. Overall, they found that children who spoke two or more languages often had stronger executive functioning skills. This means they are able to control impulses and to switch between different tasks more easily than children who only spoke one language.

“We discovered that multilingualism is associated with improvements in executive function, which in turn is associated with improvements in autism symptoms,” Perry said. “There were hints of this in the literature before, but it was exciting to see how far reaching those differences were in this research.”

Published in the journal Autism Research, the results are significant because executive functioning skills are a key challenge for children on the spectrum but are important for all kids to thrive in school and later in the workplace. Yet, the team found the benefits of speaking more than one language were not limited to children with autism.

Key features of autism include social communication difficulties and restrictive and repetitive behaviors, as well as difficulty with executive function skills. These are mental processes that help us plan, focus, remember instructions, and manage multiple tasks effectively. While executive function skills develop and improve across the lifespan, individuals with autism often struggle with executive functioning, impacting their ability to manage daily tasks and adapt to new situations.

The study also looked at the impact of multilingualism on core symptoms of autism, including perspective taking, restricted and repetitive behaviors, and social communication.

“We also found that multilingual children have enhanced perspective taking skills, or the ability to understand someone else’s thoughts or point of view,” Romero added.

An idea called joint activation from the field of neuroscience can help explain the results. Prior research suggests that the bilingual brain has two languages constantly active and competing. As a result, the daily experience of shifting between these languages is associated with enhanced executive control. This concept is also known as the “bilingual advantage” and is a topic of much debate.

“If you have to juggle two languages, you have to suppress one in order to use the other. That’s the idea, that inhibition — or the ability to stop yourself from doing something — might be bolstered by knowing two languages,” said Uddin, now a professor at the University of California, Los Angeles, and director of the Brain Connectivity and Cognition Laboratory.

Romero realized she wanted to explore this topic while working in Uddin’s neuroscience lab on campus that was doing brain imaging research on children with autism. She noticed that some bilingual families did not speak to their child in their native language because they thought it may be too challenging and harmful for their child to learn more than one language.

“I started investigating this to let families know there’s no detriment for their child to learn another language, whether or not they have a neurodevelopmental disorder,” she said. “We know this through research, but often it takes time to translate that to families, so I hope this study helps address that.”

In his work as executive director of the University’s Center for Autism and Related Disabilities, Alessandri said this question often comes up with parents.

“It is wonderful to have sound research supporting our general recommendation to not restrict language exposures to children in multilingual homes,” Alessandri said. “This will surely bring a sense of relief to many of our families living with loved ones with autism.”

Romero and Perry are now doing further research with preschool children to see if bilingualism also has an impact on kids’ peer interactions, which are crucial for children’s social and cognitive development. And at UCLA, Uddin is currently conducting a large follow-up study to further investigate the impact of multilingualism on brain and cognitive development in children with autism.

Now, new research led by Joshua Kim and Mathew Madhavacheril at the University of Pennsylvania and their collaborators at Lawrence Berkeley National Laboratory suggests our universe has become “messier and more complicated” over the roughly 13.8 billion years it’s been around, or rather, the distribution of matter over the years is less “clumpy” than expected.

“Our work cross-correlated two types of datasets from complementary, but very distinct, surveys,” says Madhavacheril, “and what we found was that for the most part, the story of structure formation is remarkably consistent with the predictions from Einstein’s gravity. We did see a hint for a small discrepancy in the amount of expected clumpiness in recent epochs, around four billion years ago, which could be interesting to pursue.”

The data, published in the Journal of Cosmology and Astroparticle Physics and the preprint server arXiv, comes from the Atacama Cosmology Telescope’s (ACT) final data release (DR6) and the Dark Energy Spectroscopic Instrument’s (DESI) Year 1. Madhavacheril says that pairing this data allowed the team to layer cosmic time in a way that resembles stacking transparencies of ancient cosmic photographs over recent ones, giving a multidimensional perspective of the cosmos.

“ACT, covering approximately 23% of the sky, paints a picture of the universe’s infancy by using a distant, faint light that’s been travelling since the Big Bang,” says first author of the paper Joshua Kim, a graduate researcher in the Madhavacheril Group. “Formally, this light is called the Cosmic Microwave Background (CMB), but we sometimes just call it the universe’s baby picture because it’s a snapshot of when it was around 380,000 years old.”

The path of this ancient light throughout evolutionary time, or as the universe has aged, has not been a straight one, Kim explains. Gravitational forces from large, dense, heavy structures like galaxy clusters in the cosmos have been warping the CMB, sort of like how an image is distorted as it travels through a pair of spectacles. This “gravitational lensing effect,” which was first predicted by Einstein more than 100 years ago, is how cosmologists make inferences about its properties like matter distribution and age.

DESI’s data, on the other hand, provides a more recent record of the cosmos. Based in the Kitt Peak National Observatory in Arizona and operated by the Lawrence Berkeley National Laboratory, DESI is mapping the universe’s three-dimensional structure by studying the distribution of millions of galaxies, particularly luminous red galaxies (LRGs). These galaxies act as cosmic landmarks, making it possible for scientists to trace how matter has spread out over billions of years.

“The LRGs from DESI are like a more recent picture of the universe, showing us how galaxies are distributed at varying distances,” Kim says, likening the data to the universe’s high school yearbook photo. “It’s a powerful way to see how structures have evolved from the CMB map to where galaxies stand today.

By combining the lensing maps from ACT’s CMB data with DESI’s LRGs, the team created an unprecedented overlap between ancient and recent cosmic history, enabling them to compare early- and late-universe measurements directly. “This process is like a cosmic CT scan,” says Madhavacheril, “where we can look through different slices of cosmic history and track how matter clumped together at different epochs. It gives us a direct look into how the gravitational influence of matter changed over billions of years.”

In doing so they noticed a small discrepancy: the clumpiness, or density fluctuations, expected at later epochs didn’t quite match predictions. Sigma 8 (σ8), a metric that measures the amplitude of matter density fluctuations, is a key factor, Kim says, and lower values of σ8 indicate less clumping than expected, which could mean that cosmic structures haven’t evolved according to the predictions from early-universe models and suggest that the universe’s structural growth may have slowed in ways current models don’t fully explain.

This slight disagreement with expectations, he explains, “isn’t strong enough to suggest new physics conclusively — it’s still possible that this deviation is purely by chance.”

If indeed the deviation is not by chance, some unaccounted-for physics could be at play, moderating how structures form and evolve over cosmic time. One hypothesis is that dark energy — the mysterious force thought to drive the universe’s accelerating expansion — could be influencing cosmic structure formation more than previously understood.

Moving forward, the team will work with more powerful telescopes, like the upcoming Simons Observatory, which will refine these measurements with higher precision, enabling a clearer view of cosmic structures.

Researchers from the University of California San Diego may help bring science fiction to reality by providing a divining rod to guide future space missions, including NASA’s Artemis campaign, which seeks to explore and, eventually, inhabit the moon. Their work appears in a special issue of Proceedings of the National Academy of Sciences (PNAS) called “Water on the Moon and Mars,” which features Artemis I on its cover.

The researchers included the father-son team of Mark Thiemens, UC San Diego Distinguished Professor of Chemistry and Biochemistry, and Maxwell Thiemens, a research fellow at the Vrije Universiteit Brussel, who is also an alumnus of Scripps Institution of Oceanography.

In 1967, Nobel laureate Harold Urey and James Arnold — both faculty members in UC San Diego’s Department of Chemistry — were among the first to receive Apollo 11 lunar samples. Urey was one of the first scientists to theorize that there was water on the moon, particularly in the permanently shadowed regions of the moon’s poles. Today, scientists believe that water on the moon originated from one of three sources:

• indigenous to the moon,
• created by solar winds (where hydrogen from the sun reacts with oxygen at high energy on the moon and likely Mars to create water)
• deposition (from icy comets that have crashed onto the lunar surface).

On Earth, human civilizations often bubble up near bodies of water and it would be no different in space. On the moon, it’s important to know the origin of the water sources because it will give astronauts guidance on where it would be most prudent to set up bases and habitats.

To learn about the origin of water on the moon, Morgan Nunn Martinez (who was a UC San Diego graduate student at the time) extracted very small amounts from lunar rocks collected from the 1969 Apollo 9 mission. It may sound implausible to get water from a rock, but it is possible through “thermal release,” a process where lunar samples were heated to 50, 150 and 1,000 degrees Celsius (122, 302, and 1,832 degrees Fahrenheit respectively). As it turns out, these rocks were surprisingly “wet.”

The lowest temperatures released lightly bound water molecules — those molecules that are attached to other molecules (in this case, lunar rock) through a weak attraction. At 1,000 degrees Celsius, tightly bound water molecules, which are more deeply embedded in the rock, were released.

Through this process, gas water molecules are collected, then purified so that only the oxygen remains. The team then measured the composition of three different oxygen isotopes.

Isotopes are atoms of the same element that have varying numbers of neutrons, which changes their mass — the more neutrons, the heavier the atom. These measurements are particularly useful in determining a substance’s origin and age.

Think of it like space forensics. In the way humans have unique fingerprints, astronomical objects, like comets and the sun, have unique signatures. Scientists are able to look at the oxygen isotope measurements and determine the origin of the water.

Their data revealed that most of the lunar water likely originated from the moon itself or from comet impacts. Contrary to popular belief, solar winds did not significantly contribute to the moon’s water stores.

“What’s nice about this research is that we’re using the most advanced scientific measurements and it supports common sense ideas about lunar water — much of it has been there since the beginning and more was added by these icy comet impacts,” stated Maxwell Thiemens. “The more complicated method of solar wind-derived water doesn’t appear to have been that productive.”

Although not a main thrust of the paper, the researchers also measured samples from Mars. If NASA’s Artemis program is able to successfully colonize humans on the moon, it would bode well for the ultimate mission of inhabiting Mars.

“This kind of work hasn’t been done before and we think it can provide NASA with some valuable clues about where water is located on the moon,” stated Mark Thiemens. “The real goal of Artemis is to get to Mars. Our research shows that likely there is at least as much water on Mars as on the moon, if not more.”

Of course, locating the water is only the first step. Being able to extract it from lunar rocks and soil in quantities large enough to sustain life will require further technological advancements and discovery.

Full list of authors: Maxwell Thiemens (Vrije Universiteit Brussel), Morgan Nunn Martinez and Mark Thiemens (UC San Diego).

This research was supported, in part, by a NASA Earth and Space Science Fellowship, a Zonta International Amelia Earhart Fellowship and the Achievement Rewards for College Scientists Fellowship.

“We could target individual cells and explore how this affected their ability to stay healthy and functional,” says Chiara Musumeci, researcher at the Laboratory of Organic Electronics, LOE, at Linköping University.

The brain is controlled by electrical signals that are converted into chemical substances in the communication between the brain cells. It has long been known that different parts of the brain can be stimulated with the help of electricity. But methods are often imprecise and affect large parts of the brain. Sometimes, metal electrodes are needed to hit the right part of the brain, which entails a risk that the hard electrode instead damages the brain tissue, causing inflammation or scarring.

A solution for treating specific parts of the brain could involve conductive plastics, also known as polymers.

“The goal is to combine biological systems with electrodes, specifically using organic conductive polymers. As polymers are soft and conformable and can transport both electricity and ions, they are preferable to conventional electrodes,” says Chiara Musumeci.

Together with researchers at Karolinska Institutet, the research team at Campus Norrköping has succeeded in anchoring the conductive plastic to individual living cell membranes. This opens up for future precise treatments of neurological diseases.

“At the moment, our results are rather general, which is a good thing, as our future research can explore what types of diseases this important tool would be suitable for. But more research is needed before we can say anything with any certainty,” says Alex Bersellini Farinotti, researcher at Karolinska Institutet.

Previous attempts to anchor organic electronics at the cell surface have been made, but with genetically modified cells that make the membranes more receptive. In their present study, the researchers have not used genetically modified cells and yet managed to achieve a tight coupling without affecting the cell’s other functions. This is the first time this has been done.

To succeed, the researchers used a two-step process where an anchor molecule is first used to create an attachment point in the cell membrane. At the other end of the molecule is a structure where the polymer electrode itself can attach.

The next step in the research is to get a more evenly distributed and stable anchoring over the membrane and to see how the polymer coupling behaves over time. Hanne Biesmans is a doctoral student at LOE and believes that there is great potential but also many challenges left to solve.

“We have taken a big step forward now. But we can’t say with any certainty that it will work in living tissue. This is basic research, where we are now trying to figure out the way forward.”

Ocean temperatures were rising at about 0.06 degrees Celsius per decade in the late 1980s, but are now increasing at 0.27 degrees Celsius per decade.

Published today (Tuesday, 28 January 2025) in Environmental Research Letters, the study helps explain why 2023 and early 2024 saw unprecedented ocean temperatures.

Professor Chris Merchant, lead author at the University of Reading, said: “If the oceans were a bathtub of water, then in the 1980s, the hot tap was running slowly, warming up the water by just a fraction of a degree each decade. But now the hot tap is running much faster, and the warming has picked up speed. The way to slow down that warming is to start closing off the hot tap, by cutting global carbon emissions and moving towards net-zero.”

Energy imbalance

This accelerating ocean warming is driven by the Earth’s growing energy imbalance — whereby more energy from the Sun is being absorbed in the Earth system than is escaping back to space. This imbalance has roughly doubled since 2010, in part due to increasing greenhouse gas concentrations, and because the Earth is now reflecting less sunlight to space than before.

Global ocean temperatures hit record highs for 450 days straight in 2023 and early 2024. Some of this warmth came from El Niño, a natural warming event in the Pacific. When scientists compared it to a similar El Niño in 2015-16, they found that the rest of the record warmth is explained by the sea surface warming up faster in the past 10 years than in earlier decades. 44% of the record warmth was attributable to the oceans absorbing heat at an accelerating rate.

Expect more warming

The findings show that the overall rate of global ocean warming observed over recent decades is not an accurate guide to what happens next: it is plausible that the ocean temperature increase seen over the past 40 years will be exceeded in just the next 20 years. Because the surface oceans set the pace for global warming, this matters for the climate as a whole. This accelerating warming underscores the urgency of reducing fossil fuel burning to prevent even more rapid temperature increases in the future and to begin to stabilise the climate.

Research into ageing is producing an overwhelming amount of data, making it difficult to determine which interventions — such as new medicines, dietary changes, or exercise routines — are safe and effective. This study investigated how AI can analyse data more efficiently and accurately, by proposing a comprehensive set of standards for AI systems to ensure they deliver accurate, reliable, and understandable evaluations through their ability to analyse complex biological data.

The researchers identified eight critical requirements for effective AI-based evaluations:

1. Correctness of the evaluation results. Data quality will be assessed for accuracy.
2. Usefulness and comprehensiveness.
3. Interpretability and explainability of the evaluation results. Clarity and conciseness of the results and the given explanations.
4. Specific consideration of causal mechanisms affected by the intervention.
5. Consideration of data in a holistic context:
   1. Efficacy and toxicity, and evidence for the existence of a large therapeutic window;
   2. Analyses in an “interdisciplinary” setting.
6. Enabling reproducibility, standardisation, and harmonisation of the analyses (and of the reporting).
7. Specific emphasis on diverse longitudinal large-scale data.
8. Specific emphasis on results that relate to known mechanisms of ageing.

Telling LLMs about these requirements as part of the prompting improved the quality of the recommendations they produced.

Professor Brian Kennedy from the Department of Biochemistry & Physiology, and Healthy Longevity Translational Research Programme at NUS Medicine, who co-led the study, said, “We tested AI methods using real-world examples such as medicines and dietary supplements. We found that by following specific guidelines, AI can provide more accurate and detailed insights. For instance, when analysing rapamycin, a drug often studied for its potential to promote healthy ageing, the AI not only evaluated its efficacy but also provided context-specific explanations and caveats, such as possible side effects.”

“The study’s findings could have far-reaching effects,” added Professor Georg Fuellen, Director, Institute for Biostatistics and Informatics in Medicine and Ageing Research, Rostock University Medical Center, who co-led the study, “For healthcare, telling the AI about the critical requirements of a good response can enable it to find more effective treatments and make them safer to use. Generally, AI tools could design better clinical trials and help tailor health recommendations to each person. This research is a major step toward using AI to improve health outcomes for everyone, especially as they age.”

Moving forward, the team is now focusing on a large-scale study of how to best prompt AI models for longevity-related intervention advice, to evaluate their accuracy and reliability for a wide array of carefully designed benchmarks, that is, curated, high-quality data. The validation of such AI systems is specifically important because the longevity interventions may then be implemented by a large number of healthy people. Prospective studies will need to demonstrate that AI-based evaluations can accurately predict successful outcomes in human trials, paving the way for safer and more effective health interventions.

The team hopes to use their findings to make health and longevity interventions more precise and accessible, and ultimately improve the quality and duration of life. Collaboration between researchers, clinicians, and policymakers will be essential to establish robust regulatory frameworks, ensuring the safe and effective use of AI-driven evaluations.