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When less is more: Scaling law explains why ultrathin materials get stronger as they get thinner

One of the most fascinating aspects of physics is that nature often behaves in ways that seem completely counterintuitive. A good example comes from ultrathin materials. If I take a sheet of material and make it thinner and thinner, most people would expect it to become weaker. After all, there is less material left to bear a load.

Yet over the last decade, experiments and simulations have repeatedly shown something surprising: when certain materials become extremely thin—only a few nanometers or even a few atomic layers thick—they can become dramatically more resistant under extreme mechanical loading.

This phenomenon has been observed in systems as different as graphene, graphene oxide, and ultrathin polymer films. The effect was clear, but the reason behind it remained unclear. Why should materials with completely different chemistry and structure all exhibit a similar trend?

Nanoparticles from tattoos circulate inside the body, study finds

The elements that make up the ink in tattoos travel inside the body in micro and nanoparticle forms and reach the lymph nodes, according to a study published in Scientific Reports on 12 September by scientists from Germany and the ESRF, the European Synchrotron, Grenoble (France). It is the first time researchers have found analytical evidence of the transport of organic and inorganic pigments and toxic element impurities as well as in depth characterization of the pigments ex vivo in tattooed tissues. Two ESRF beamlines were crucial in this breakthrough.

“When someone wants to get a tattoo, they are often very careful in choosing a parlour where they use sterile needles that haven’t been used previously. No one checks the chemical composition of the colours, but our study shows that maybe they should,” explains Hiram Castillo, one of the authors of the study and scientist at the ESRF.

The reality is that little is known about the potential impurities in the colour mixture applied to the skin. Most tattoo inks contain organic pigments, but also include preservatives and contaminants like nickel, chromium, manganese or cobalt. Besides carbon black, the second most common ingredient used in tattoo inks is (TiO2), a white usually applied to create certain shades when mixed with colorants. TiO2 is also commonly used in food additives, sunscreens and paints. Delayed healing, along with skin elevation and itching, are often associated with white tattoos, and by consequence with the use of TiO2.

Is extracting oxygen from lunar soil the future of space exploration?

A new race to the moon is emerging between the United States and China. Unlike fifty years ago, the goal is no longer just about landing and leaving, but establishing a base that allows for a sustainable presence and extended stays on the surface of our natural satellite. The objective is now to use the moon as a testing ground for technologies that will enable us to travel further, particularly to Mars.

One of these key technologies is in-situ resource utilization (ISRU), which involves using available resources on-site to produce the consumables necessary for human activities: oxygen, water, rocket fuels, or construction materials. By producing these essentials directly on the moon, it will be possible to significantly reduce the mass of cargo sent from Earth, thereby reducing the logistical and financial costs of space exploration. Instead of importing these resources from Earth, the goal is to learn how to live on the moon.

Breaking down lunar dust to extract oxygen At the dawn of humanity’s sustainable return to the moon, ISRU is emerging as a strategic pivot. One of the major challenges is producing oxygen from regolith, the layer of soil covering the moon, primarily composed of small rock fragments and dust. The composition of regolith is complex, mainly consisting of several minerals (plagioclase, pyroxene, olivine) themselves made up of a mixture of metal oxides—chemical compounds that combine oxygen with another element such as silicon, iron, or calcium.

AI-guided catalyst turns CO₂ and waste into fertilizer at industrially relevant rates

Researchers from the National University of Singapore (NUS) have developed a computation-guided strategy to produce urea more efficiently from carbon dioxide and nitrate. By combining large language models, density functional theory calculations and experiments, the approach identified a cadmium-modified iron oxide catalyst that maintains high urea selectivity at practical current densities.

Urea is one of the world’s most widely used fertilizers, but its conventional production comes at a heavy environmental cost. The industrial process accounts for more than two percent of global energy consumption and releases over 200 million tons of carbon dioxide each year.

A cleaner alternative is to produce urea electrochemically, using low-carbon electricity to convert carbon dioxide and nitrate into a useful product. However, this approach has been difficult to scale up. At the high current densities needed for practical production, the catalysts often favor competing side reactions, such as hydrogen gas formation or carbon dioxide reduction to other products.

Faster biological aging consistently linked to poverty and discrimination

The study, published in Nature Human Behaviour, demonstrates that social inequality, such as poverty and racism, is related to biological aging measured in the epigenome, also known as “epigenetic clocks.” Epigenetic clocks analyze patterns of chemical marks on DNA to estimate a person’s biological age or the rate at which their body is aging. These tools are increasingly used by scientists to study how environmental exposures, lifestyle and social conditions affect health across the life course.

Previous individual studies have shown that epigenetic clocks are sensitive to socioeconomic and racial or ethnic disparities. However, because multiple types of epigenetic clocks exist, it has remained unclear which measures best capture the effects of social determinants of health, at which stages of life socioeconomic exposures most affect epigenetic aging, and whether associations differ by sex or by technical factors such as the tissue in which epigenetic data are collected. This study integrates findings across many independent studies, offering a comprehensive test of whether these associations are consistent and robust.

Transparent OLED advance could improve AR displays and smart windows

Seoul National University College of Engineering announced that a research team led by Prof. Yongtaek Hong from the Department of Electrical and Computer Engineering has developed a high-performance transparent organic light-emitting diode (OLED) incorporating highly conductive transparent metal mesh top electrodes fabricated using a selective metal deposition technique. The research was published in the journal Materials Horizons and was selected as the outside front cover image for the issue.

Transparent OLEDs have attracted significant attention for next-generation applications, including advanced displays, augmented reality (AR), automotive displays and smart windows, because of their capability for bidirectional light emission. However, despite achieving high optical transparency and excellent electrical performance, conventional transparent electrodes often face limitations when directly integrated into OLED devices because their fabrication processes can chemically or physically damage the underlying organic layers.

To address this challenge, the research team developed a metal-patterning technology based on a high-resolution transfer-printing process using a metal-vapor-desorption layer (MVDL). This approach enables the fabrication of highly conductive transparent metal mesh patterns with micrometer-scale resolution without requiring chemical washing or lift-off processes. As a result, high-quality vapor-deposited metal patterns can be directly formed on organic stacks while minimizing damage to the underlying organic device layers.

Popular joint pain supplement might increase Alzheimer’s risk, study says

A popular over-the-counter supplement taken for joint pain might increase people’s risk for Alzheimer’s disease, a new study says.

Glucosamine use is associated with a 25% higher odds that a person will progress from mild cognitive impairment to dementia and Alzheimer’s disease, researchers report in the journal Nature Metabolism.

“While it’s an association and not proof of causality, it does raise an important clinical question that now deserves much more attention,” researcher Matt Gentry said in a news release. He’s chair of biochemistry and molecular biology at the University of Florida.

One photon, two reactions—new catalyst converts CO₂ and biowaste simultaneously

Researchers have developed a solar-driven catalyst material that harnesses the energy of a single photon to reduce carbon dioxide and oxidize organic waste at the same time, producing valuable chemicals in both reactions.

Scientists at the University of Nottingham have created two catalyst materials that, when coupled together within the same reactor, can simultaneously convert carbon dioxide (CO₂) into a valuable chemical and biomass-derived feedstock into building blocks for sustainable plastics, driven solely by solar light. The research has been published in Communications Materials.

A bias-free photoelectrochemical (PEC) reactor consists of two connected compartments, each containing the newly developed catalysts. When sunlight shines on one compartment, each photon drives the oxidation of a biowaste molecule. The electron released during this process is then transferred to the second compartment, where it reduces CO₂ to formate.

Electron matter waves gain ultrafast torque that flips handedness in femtoseconds

Many natural processes, ranging from magnetism to chemical reactions, entail the movement and rotation of particles at very small scales. In quantum mechanics, particles exhibit both particle-like and wave-like behaviors, and their states can be described mathematically using representations known as wavefunctions.

The reliable manipulation of wave-like properties of particles as small as atoms or single electrons could open new possibilities both for studying matter and for engineering materials with desirable characteristics. Notably, controlling the angular momentum, which is the quantum property related to rotational motion, of ultrasmall particles at ultrafast timescales has so far proved very challenging when only using conventional, laser-based approaches.

Researchers at Universität Konstanz recently devised a new approach to create electron beams with an ultrafast internal torque (i.e., twisting motion). Their proposed strategy, outlined in a paper published in Nature Physics, could be a promising tool for exploring material dynamics and quantum phenomena at atomic and subatomic scales.

CO₂ injection reveals hidden cement chemistry behind 13% stronger early strength

One September day, it started to snow inside MIT’s Pierce Laboratory. Researchers depressurized a tank of liquid carbon dioxide (CO2), instantly freezing it and releasing solid flakes. These were blended into cement paste and pressed into disks roughly the size of a dime, each sealed with a thin layer of vegetable oil to keep water in and air out. The team trained lasers on each one, observing for the first time the transient chemical reaction that might explain why CO2-injected cement paste gains strength faster.

Injecting CO2 into cement products like concrete is one way to store it and keep it out of the atmosphere. The process has attracted commercial interest, with a growing number of companies offering CO2-injected concrete mixes. But until now, the underlying cement chemistry hadn’t been directly visualized.

A new paper in the Journal of the American Ceramic Society —led by associate professor Admir Masic and first-authored by graduate student Marcin Hajduczek, both of the MIT Concrete Sustainability Hub and MIT Department of Civil and Environmental Engineering—describes the chemical sequence that unfolds after CO2 meets fresh cement paste. Co-authors include MIT colleagues Santiago El Awad and Franz-Josef Ulm, alongside researchers from IIT Jodhpur and CarbonCure Technologies.

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