A new approach allows researchers to catch a photocatalyst in action

A new approach allows researchers to catch a photocatalyst in action

Using SLAC’s X-ray laser, the method revealed atomic motions in a simple catalyst, opening the door to study more complex molecules key to chemical processes in industry and nature.

Catalysts facilitate crucial chemical reactions in nature and industry alike. In a subset of them, catalytic activity is triggered by light. For example, when iron pentacarbonyl – a molecule in which a central iron atom is surrounded by five carbon monoxide groups – is exposed to light, the iron sheds its carbon monoxide groups one after another, creating spots for other molecules to dock on to during a catalytic reaction.  

Although this process has been studied extensively with spectroscopy, a method that shows how energy moves around in molecules, key details of how the catalyst’s atoms change structure after being hit by light remain unknown. 

Now, writing in the journal Nature Communications, a team led by researchers at the Department of Energy’s SLAC National Accelerator Laboratory report how they used ultrafast X-rays from the Linac Coherent Light Source (LCLS), combined with recent theoretical advancements, to reveal those atomic motions on a timescale of femtoseconds, millionths of a billionth of a second. The technique could be used to observe speedy atomic motions in more complex catalysts. 

Understanding how energy flows through molecules and how atoms move in real space and time brings us one step closer to controlling chemical reactions, helping us design materials.Adi NatanSLAC Staff Scientist and Principal Investigator at the Stanford PULSE Institute

“Part of the fun is to make tools that will open new doors,” said Adi Natan, principal investigator and staff scientist at the Stanford PULSE Institute, a joint institute of SLAC and Stanford University. “And being able to see how molecular structures evolve with unprecedented detail will allow us to learn something new about the chemistry of molecules.”

Read more on SLAC website

Researchers find a potential treatment for mitochondrial damage that causes disease

Researchers find a potential treatment for mitochondrial damage that causes disease

Oxidizing chemicals break this cellular power plant into useless bits, leading to Parkinson’s disease, ALS, heart disease, diabetes, cancer and more. A small molecule could block the process.

Mitochondria are the cell’s power plants: They turn the food we eat into the energy our cells can use. But when stress hijacks the process they use to maintain their quality, they get snipped into useless fragments and go into a tailspin that spreads from cell to cell and triggers a wide range of human diseases. As researchers learn more about the health impacts of rogue mitochondria, they’ve been searching for ways to prevent or treat them. 

Now researchers at the Department of Energy’s SLAC National Accelerator Laboratory and Stanford University say they’ve found a way to protect mitochondria from stress induced by exposure to a highly reactive molecule called hydrogen peroxide. This particular type of damage is linked to neurogenerative diseases like Parkinson’s and Amyotrophic Lateral Sclerosis (ALS), heart disease, diabetes, inflammatory bowel disease and cancer, among others.

In experiments with human kidney cells, the research team reported, adding a small molecule called SP11 to the fragmented mitochondria made them hale and whole again. 

The team described their work in a May 6 report in Nature Communications, and Stanford has patented SP11 as a potential candidate for drug development.

“If we can keep mitochondria in pristine shape, we may really help address many chronic human diseases. That’s why we embarked on this project,” said Stanford Professor Daria Mochly-Rosen, a senior author of the report whose research into the chemistry of proteins has yielded both potential and successfully deployed drugs.

When bad mitochondria do this to a healthy cell, they can kill it. When healthy mitochondria do it to a sick cell, they can help it heal.Daria Mochly-RosenStanford University Professor of Chemical and Systems Biology

Not just a power plant 

Although mitochondria are best known for producing energy, that’s not their only role. “They’re so busy! This organelle is so critical,” Mochly-Rosen said. For instance, they’re responsible for constructing some of the cell’s molecular building blocks and for deliberately killing cells whose DNA is damaged. 

For a long time, scientists assumed that mitochondria were confined to their host cells, but they recently discovered this isn’t true. “Now we know they can exit one cell and enter another one,” Mochly-Rosen said. “When bad mitochondria do this to a healthy cell, they can kill it. When healthy mitochondria do it to a sick cell, they can help it heal.”

Seventeen years ago, Mochly-Rosen and her colleagues trained a microscope on cells from a rat with high blood pressure and discovered that the mitochondria were fragmented into small pieces. This set off a quest to find out what was happening and how to prevent or fix it.

Hijacking fission

Mitochondria are often depicted as little jellybeans whose shape never changes, said Suman Pokhrel, who was a PhD student at SLAC and Stanford at the time he led the study. But in real life they form an ever-changing, fibril-like network. Thousands of them surround the nucleus of each cell, and they’re constantly dividing and fusing with each other. Mitochondria need to maintain a balance between division and fusion to stay healthy, increase their numbers and make enough energy.

In healthy mitochondria, a protein called Drp1 attaches to the mitochondrial membrane and initiates division via a go-between protein called Mff. But when mitochondria send out distress signals – for instance, if they’ve been attacked by a reactive oxygen molecule like hydrogen peroxide and can’t repair the damage fast enough – Drp1 attaches to a protein called Fis1 and uses it as a go-between instead. 

Fis1 directs mitochondrial fission in yeast, but in humans it only brings grief. It hijacks the normal process mitochondria use to divide neatly in half and instead squeezes them into uneven pieces that fragment into even smaller ones that don’t produce enough energy. 

Read more on SLAC website

Image: An image shows thousands of mitochondria (purple dots) surrounding nuclei of about 50 human kidney cells. 

Credit: Gwangbeom Heo/Stanford University

Exploring how tiny particles affect our lungs

Exploring how tiny particles affect our lungs

Very small particles — either naturally occurring in the air or engineered for industrial purposes — can penetrate deep into our lungs because they are smaller than 100 nanometers (about 1,000 times thinner than a human hair). These particles can cause serious long-term health problems, such as inflammation, and tissue damage, which can lead to fibrosis or even cancer.

To assess the health risks of these nanoparticles and predict how they might affect us, it is essential to understand exactly how they interact with lung cells at the molecular level — from the moment they come into contact with lung tissue. Such a detailed investigation requires sophisticated imaging techniques that can reveal both the structure and function of these tiny interactions. One powerful method is Correlated Light and Electron Microscopy (CLEM), which combines different types of microscopes to provide a more complete picture. Thanks to recent advances in resolution and sensitivity, CLEM has become an important tool in biological research.

In our study, we developed a new, expanded CLEM approach that combines several advanced imaging techniques to better understand how lung cells respond to a specific type of nanoparticle: titanium dioxide nanotubes (TiO₂ NTs), which are known to cause inflammation and are considered potentially carcinogenic. Our approach integrates a wide range of complementary tools, providing a morpho-functional assessment of the studied interface (Fig. 1):

  • Confocal Laser-Scanning Microscopy (CLSM), together with Fluorescence Lifetime Imaging Microscopy (FLIM) and Hyperspectral Fluorescence Imaging (fHSI) to study live cells at the organelle and nanoscopic scales.
  • Scanning Electron Microscopy (SEM) and Helium Ion Microscopy (HIM) for extremely detailed surface imaging.
  • Synchrotron-based X-ray Fluorescence (SR μXRF) combined with Scanning Trasnmission X-ray Microscopy (STXM) for analyzing the chemical elements in and around the cells at submicrometric length scales.

Among these, SR μXRF has crucial importance, as it provides chemical sensitivity. Together, these methods allowed us to study interactions across many scales — from whole cells down to individual molecules.

Scanning transmission X-ray Microscopy (STXM) combined with low energy micro-X-ray Fluorescence (LE-μXRF) were carried out at the TwinMic beamline of Elettra. These measurements were complemented by Correlative light,electron and ion microscopy, namely fluorescence lifetime imaging microscopy (FLIM), hyperspectral fluorescence imaging (fHSI), scanning electron microscopy (SEM) and ultra-high resolution helium ion microscopy (HIM).

Read more on Elettra website

Self-Generated Magnetic Handles in Modified Mammalian Cells

Self-Generated Magnetic Handles in Modified Mammalian Cells

CIENTIFIC ACHIEVEMENT

Researchers genetically engineered mammalian cells to produce their own magnetic “handles” and revealed their magnetic, physical, and chemical properties, measured in part at the Advanced Light Source (ALS).

SIGNIFICANCE AND IMPACT

The work provides a foundation for future bioengineering efforts aimed at enabling genetically controlled magnetic manipulation of molecular processes in living mammalian cells.

An internal compass for cells

Some bacteria have evolved the remarkable ability to align themselves with Earth’s magnetic field, owing to self-synthesized chains of magnetic nanocrystals that provide them with an internal compass needle. It’s thought that following magnetic field lines helps these single-celled organisms propel themselves toward optimal (for them) environments.

Multicellular organisms—including humans—can also benefit from cellular compasses, or magnetic “handles,” to maneuver cells as needed. Possible future applications include cell sorting, cell tracking (and imaging), and targeted drug delivery. However, the genetic programming that allows bacteria to natively produce magnetic organelles is lacking in mammals, and attempts to introduce magnetic agents into mammalian cells are stymied by cellular defense mechanisms.

To get around this, a large multinational research collaboration based in Germany genetically modified mammalian cells to self-produce protein nanocompartments in which iron oxides can be created and stored. The group then characterized the magnetic, physical, and chemical properties of the nanocompartment cargo and demonstrated the ability to manipulate the resulting live engineered cells using magnetic fields.

Sample synthesis and analysis

The researchers introduced into mammalian cells a set of genetic constructs (engineered DNA) for the overexpression of encapsulin, the protein building block of nanocompartment shells produced by Quasibacillus thermotolerans bacteria. Also included were constructs for a red fluorescent protein for detection purposes and a ferroxidase, an enzyme that promotes the oxidation of reactive Fe2+ to more stable Fe3+ (to facilitate iron oxide accumulation). Cellular uptake of Fe2+ was enhanced by co-expression of a protein that transports iron into cells. Finally, to provide a source of iron, the cell medium was supplemented with ferrous ammonium sulfate.

After 72 hours, the modified cells were sorted using magnetic-activated cell sorting (MACS) columns. Within the cell fraction retained in the MACS columns, the researchers discovered encapsulin shells that contained ultrafine (1–3 nm) quasicrystalline ferric oxide/hydroxide cores that exhibited ferrimagnetism and paramagnetism. However, determining the precise identity of the magnetic particles required the ability to distinguish between different species of iron oxide at the scale of individual particles.

Read more on ALS website

Image: Mammalian cells were genetically modified to synthesize protein nanocompartments in which iron oxide biomineralization takes place. The compartments, naturally produced by the bacterium Quasibacillus thermotolerans (Qt), are constructed of proteins called encapsulins. The shell size and symmetry are indicated by a triangulation number (T = 4 corresponds to a relatively large, ~43 nm shell). Co-expressed with the encapsulin was a ferroxidase (IMEF), which facilitates the accumulation of iron oxide by catalyzing oxidation of Fe2+ to Fe3+.

Stopping infections before they can start

Stopping infections before they can start

As concerns about waning antibiotic effectiveness grow, researchers are using unique tools to search for new ways to keep bacteria from causing infections in both humans and animals.

“We’re really interested in finding out how bacteria make their connection with the host cells they’re going to infect,” says Dr. Peter Davies, professor of biochemistry and former Canada Research Chair in protein engineering at Queen’s University. Davies and his colleagues used the Canadian Light Source (CLS) at the University of Saskatchewan to visualize the structure of long, thin proteins called adhesins, which most bacteria have, and which bind to a sugar molecule on the surface of a cell. Once attached, “the bacteria start to form a colony and then eventually a biofilm. This is how they get started in an infection,” he explains.

The goal of the research, recently published in the journal Molecular and Cellular Biology, is to find a way to interrupt that attachment process — to “put something in there that would fool them (bacteria) and not allow them to bind to the host cells.”

With the help of an artificial-intelligence (AI) program that can create a three-dimensional model of a protein, says Davies, “we’ve learned how to recognize those parts of the protein that stick to the surface of cells” and begin causing infections. The researchers noted one spot on the protein that attaches to a simple sugar called fucose found on human blood cells and other organisms.

Special imaging at the CLS – called crystallography — confirmed the model and revealed a possible way to inhibit bacteria from binding to cells. In this research, Davies and colleagues were studying a bacterium called Aeromonas hydrophila, which can affect people who are immunocompromised.

Adding more fucose in with the bacterium disrupts the binding process “because they’re confused by all of this free fucose floating around,” says Davies. The protein sensors “that are looking out for the sugar on our cells” are unable to bind “because we’re flooding the market with fucose.”

Read more on CLS website

Structure of liquid carbon measured for the first time

Structure of liquid carbon measured for the first time

With the declared aim of measuring matter under extreme pressure, an international research collaboration headed by the University of Rostock and the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) used the high-performance laser DIPOLE 100-X at European XFEL for the first time in 2023. With spectacular results: In this initial experiment they managed to study liquid carbon – an unprecedented achievement, as the researchers report in the journal Nature (DOI: 10.1038/s41586-025-09035-6). 

Liquid carbon can be found, for example, in the interior of planets and plays an important role in future technologies like nuclear fusion. To date, however, only very little was known about carbon in its liquid form because in this state it was practically impossible to study in the lab: Under normal pressure carbon does not melt but immediately changes into a gaseous state. Only under extreme pressure and at temperatures of approximately 4,500 degrees Celsius – the highest melting point of any material – does carbon become liquid. No container would withstand that.

Laser compression, on the other hand, can turn solid carbon into liquid for fractions of a second. And the challenge was to use these fractions of a second to take measurements. In a previously unimaginable way, this has now become reality at the European XFEL, the world’s largest X-ray laser with its ultrashort pulses, in Schenefeld, near Hamburg.

Unique measuring technology in this combination

The unique combination of the European XFEL with the high-performance laser DIPOLE100-X was crucial for the success of the experiment. It was developed by the British Science and Technology Facilities Council and made available to scientists from all over the world by the HIBEF User Consortium (Helmholtz International Beamline for Extreme Fields). A community of leading international research institutions at the HED-HIBEF (High Energy Density) experimental station at European XFEL has now combined powerful laser compression with ultrafast X-ray analysis and large-area X-ray detectors for the first time.

In the experiment, the high-energy pulses of the DIPOLE100-X laser drive compression waves through a solid carbon sample and liquefy the material for nanoseconds, that is, for a billionth of a second. During this nanosecond, the sample is irradiated with the ultrashort X-ray laser flash of the European XFEL. The carbon atoms scatter the X-ray light – similar to the way light is diffracted by a grating. The diffraction pattern allows inferences to be drawn about the current arrangement of the atoms in the liquid carbon.

The whole experiment only lasts a few seconds but is repeated many times: every time with a slightly delayed X-ray pulse or under slightly different pressure and temperature conditions. Many snapshots combine to make a movie. Researchers have thus been able to trace the transition from solid to liquid phase one step at a time.

Read more on European XFEL website

Image: Groundbreaking experiment at European XFEL: Research team measured structure of liquid carbon for the first time

Credit: Martin Kuensting / HZDR

Seventy times faster charging possible for Lithium-ion batteries 

Seventy times faster charging possible for Lithium-ion batteries 

A research team from the Netherlands and the UK have used MAX IV to investigate a material that could make charging of lithium-ion batteries seventy times faster than today. It is a promising development for future electric vehicles and renewable energy.

Batteries have an important role to play in a sustainable society. Lightweight, fast-charging batteries open for further utilisation of electric vehicles and renewable but non-continuous energy sources, which require efficient storage to be competitive. Battery research is focused on two tracks: inventing entirely new battery technologies or further developing the lithium-ion batteries that are the most commonly used type of battery today. In the current project, the research team have used MAX IV to investigate a new electrode material for lithium-ion batteries.

“We remain interested in researching lithium-ion batteries over new technologies due to a number of factors,” says Maarten Jager, PhD candidate at the University of Groningen and one of the study’s authors.” The technology readiness level of lithium-ion batteries is very high. In the rechargeable battery market, lithium-ion batteries account for about 67% of the market share. The chemistry involved in lithium-ion batteries is also quite well-known, so there is a more straightforward path to explore new components, which could easily be implemented into the market. New technologies can often be promising, but still take years to be developed enough.”

One of the components of batteries that can be further optimised is the electrode material. The general material for the anode, the negative electrode, in lithium-ion batteries is graphite. 

“Graphite has a relatively good stability, high conductivity, and low cost. However, it also has a number of major drawbacks, which reduce its performance. It has a chemistry that limits the amount of energy each unit can store and is flammable. However, its most important drawback is the amount of power it can deliver. Graphite cannot release and store energy quickly, as it would break the electrode,” says Jager. “One major threshold consumers have for choosing an electric car is the time it takes to fully charge it at a fuel station, often over 20 minutes. Significantly bringing down this charging time without compromising battery life or storage capacity is impossible with graphite. Our experiments show that by replacing graphite with copper niobate, we can, without compromising, charge the battery 70 times faster than graphite.”

The copper niobate the researchers used in their experiment is a special so-called mixed crystal phase copper niobate containing five different crystal structures. It is the first time this type of copper niobate is investigated as a battery electrode material. Generally, so-called pure phase materials containing only one crystal structure have been thought to be the best alternative for batteries, but the new results challenge this idea.

Read more on MAX IV website

Research confirms antiferromagnetic order in real quasicrystals

Research confirms antiferromagnetic order in real quasicrystals

ANSTO was part of a team led by researchers from Tokyo University of Science and Tohoku University, who have discovered antiferromagnetism in a real icosahedral quasicrystal (iQC), reinvigorating the search for antiferromagnetic quasicrystals.

Quasicrystals (QCs) are fascinating solid materials that exhibit an intriguing atomic arrangement. Unlike regular crystals, in which atomic arrangements have an ordered repeating pattern, QCs display long-range atomic order that is not periodic. Due to this ‘quasiperiodic’ nature, QCs have unconventional symmetries that are absent in conventional crystals. 

Since their discovery in 1984, which was recognized by the Nobel Prize in 2011, quasicrystals have captured considerable attention among condensed matter physics researchers not only for their potential to realize unique quasiperiodic magnetic order but also for their possible applications in spintronics and magnetic refrigeration.

Even though ferromagnetism was recently discovered in the gold-gallium-rare earth (Au-Ga-R) icosahedral QCs, its observation may not be entirely unexpected in the condensed matter physics community, as translational periodicity is not a prerequisite for the emergence of ferromagnetic order. In contrast, antiferromagnetism, the other fundamental type of magnetic order found in nature, is inherently more sensitive to crystal symmetry. 

Although its establishment in certain types of QCs has long been anticipated by theoreticians, it has not been directly observed in real QCs. Experimentally, most magnetic iQCs exhibit spin-glass-like freezing behaviour, with no sign of long-range magnetic order, which has led researchers to question whether antiferromagnetism is even compatible with quasiperiodicity—until now.

The research team was led by Professor Ryuji Tamura from the Department of Materials Science and Technology at Tokyo University of Science (TUS), along with Mr. Takaki Abe, also from TUS, Professor Taku J. Sato from Tohoku University, and Professor Max Avdeev from the Australian Nuclear Science and Technology Organisation and The University of Sydney.

 “As was the case for the first report of antiferromagnetism in a periodic crystal in 1949, we present the first experimental evidence of antiferromagnetism occurring in an iQC,” says Prof. Tamura. Their study was published in the journal Nature Physics.

“This is a very important development, that is attracting considerable scientific interest.  Neutron scattering experiments on the Echidna instrument at the Australian Centre for Neutron Scattering provided definitive evidence of long-range antiferromagnetic ordering in the Au–In–Eu sample”, said Prof Avdeev.

“Neutron diffraction will be equally important in the studies of other magnetic quasicrystals in the follow-up studies.”

Read more on ANSTO website

Image: First direct observation of antiferromagnetism in an icosahedral quasicrystal (iQC)

Credit: Ryuji Tamura from Tokyo University of Science, Japan

Scientists unveil the mechanism of light-sensing proteins that regulate internal clock

Scientists unveil the mechanism of light-sensing proteins that regulate internal clock

Scientists have unveiled the mechanism by which proteins that regulate the circadian rhythm, called cryptochromes, trigger light signaling. They used the TR-icOS instrument at the ESRF for spectroscopic characterization of the crystals. The results are out in Science Advances.

Cryptochromes are light-sensitive proteins found in all living things, including plants and animals. They help living things keep time with day and night by controlling internal clocks and responses to light. They are important for things like sleep cycles, plant growth, and possibly even sensing Earth’s magnetic field.

Until now, scientists knew that cryptochromes function by absorbing blue light, which triggers structural changes in the protein. This activates interactions with other cellular proteins, influencing gene expression and biological rhythms. However, the mechanism by which cryptochromes manifest this light-sensing ability remained unclear.

A team led by Manuel Maestre-Reyna at the National Taiwan University has now filmed a high-resolution, 3D molecular movie of a cryptochrome in action.

To achieve that, the team used time-resolved serial femtosecond crystallography (TR-SFX) at Spring-8 Angstrom Compact X-ray Free Electron Laser in Japan initially. They collected nineteen individual “frames” spanning from 10 nanoseconds to 233 milliseconds after illumination to put together the final movie.

TR-icOS completes the picture

They then used transient absorption spectroscopy (TAS) at the TR-icOS instrument at the ESRF. Maestre-Reyna explains the importance of these experiments at the ESRF: “The role of the ESRF, and in particular of TR-icOS, was crucial. Without in crystallo TAS experiments, that currently can only be performed at TR-icOS, the biological relevance of our results would be highly questionable. Furthermore, TRX can only detect structural changes, and is limited by the data quality in its ability to do so. In other words, chemical transformations that imply only very subtle structural changes, such as electron transfer, cannot be easily tracked by TRX. On the contrary, TAS can very easily detect such electronic reconfigurations, which change protein colour. Only by combining the two was it possible to fully understand the molecular mechanism of electron-transfer based signaling of cryptochromes”.

The experiments resulted in an ultra-slow motion, atomic resolution film that explains how the cryptochrome protein amplifies the subtle photochemical signal, which then snowballs into dramatic structural changes. The process is coordinated by the protein, with three molecular regions acting in unison to accomplish sensing.

Specifically, during the initial photochemical change, flavin adenine dinucleotide (FAD), a special light-gathering moiety within the protein, used the energy of blue light to capture an electron from the cryptochrome itself, inducing a highly unstable radical pair (RP) state. Early on, the protein attempts to stabilize this short-lived species by modulating its immediate environment. These local changes cascade over time, until, by about 100 milliseconds after RP formation, entire regions of the protein unfold like a ribbon, signaling that cryptochrome has sensed light.

Understanding sleep disorders

The results of this study provide a detailed description of the molecular basis of cryptochrome function, which can be relevant in research related to circadian rhythm, such as that focused on sleep disorders.

For example, recent studies have linked mutations in human cryptochrome 2 (CRY2) to Advanced Sleep Phase Disorder (ASPD). This disorder is characterized by disruption of the circadian rhythm, as patients fall asleep by 7 pm, but wake up at ~2 am, and it is not treatable with melatonin nor other effective therapeutics.

“Whilst our research is very fundamental, we hope that by delineating the structural principles of cryptochrome we can maybe lead to new drug design for the modulation of CRY2”, concludes Maestre-Reyna.

Read more on ESRF website

Aggregated/jammed networks of silica nanoparticles in colloids lead to dramatic thickening

Aggregated/jammed networks of silica nanoparticles in colloids lead to dramatic thickening

A colloid is formed by evenly dispersing tiny particles in a liquid. Simple examples include corn starch suspended in water, or microscopic glass beads dispersed in glycol. A simple tabletop demonstration reveals a startling property these two colloids possess: gently push your fingers into the colloid and it flows like liquid but strike it with your fist and it suddenly solidifies. 

This abrupt liquid-to-solid transition is known as discontinuous shear thickening (DST). As the name implies, the dynamic response of the colloid abruptly transitions from a liquid to a solid when the applied shear force exceeds a critical value. The general consensus among materials scientists is that inter-particle friction is responsible for DST. But surprisingly little experimental evidence directly supports this hypothesis. 

To clarify this issue, researchers recently used X-ray photon correlation spectroscopy (XPCS) to observe the dynamics of glassy colloids subjected to varying shear forces. The results showed that when a strong shearing force is applied, it induces a congested network of colloidal particles governed by friction. The work was performed at beamline 8-ID-I of the Advanced Photon Source (APS), a U.S. Department of Energy (DOE) Office of Science user facility at DOE’s Argonne National Laboratory. 

Characterizing the underlying basis of DST should allow scientists to tune the dynamic behavior of many complex fluids, with real-world applications such as reducing the energy cost for mixing materials, as well as improved braking devices and body armor.

Fluids can be categorized as either Newtonian or non-Newtonian. These two categories are distinguished by reaction to shear, which is the force applied to drive fluid motion. The viscosity (ease of flow) of a Newtonian fluid does not change as shear is applied. Water and vegetable oil are both considered Newtonian fluids, since their viscosity remains unchanged when stirred.

Non-Newtonian fluids are quite different. Some non-Newtonian fluids actually become thinner (viscosity decreases) under shear as the fluid’s interior structure breaks down during shearing. In contrast, viscosity that rises slightly or moderately with shear is called continuous shear thickening (CST), while thickening that yields a solid-like state constitutes discontinuous shear thickening, or DST.

Scientists study the dynamic behavior of fluids using a device called a rheometer, which consists of two concentric cylinders as depicted in Fig. 1a. After the gap between the cylinders is filled with a colloid, the inner cylinder spins which applies a shear force. A torque sensor then measures the force/torque. What sets this particular experiment apart from other fluid-shear experiments is that XPCS data was collected simultaneously with the rheology torque measurements.

Three distinct colloids (A, B, and C) were examined, each consisting of uniformly sized silica particles dispersed in polyetheylene glycol. Particles in sample A measured 200 nanometers across and took up 60.5% of the colloid’s volume (called the volume fraction). Sample B possessed particles 360 nanometers across with a 56% volume fraction, and sample C had 360 nm particles with a 60.5% volume fraction.

Each colloid was placed in a cylindrical shear cell and then sufficient stress was applied so that the colloid approached a state nearing either CST or DST. Upon reaching equilibrium, the shear was abruptly stopped, and each colloid was monitored via XPCS for at least an hour, producing a series of speckle patterns as shown in Fig. 1b. These speckle patterns revealed how each colloid’s movements (particle velocities) changed over time.

The most interesting discovery by the team was the observation of a slowly evolving beat pattern (or heterodyne signal) in the XPCS data that occurred with both the CST-type and DST-type fluid behavior. Such a “heterodyne signal” only arises when different particles move at different speeds within the X-ray scattering volume. These particular heterodyne signals indicated the movement of mobile colloid particles against an aggregated, or jammed, network of particles produced by shear thickening.

In summary, the XPCS data showed that both CST and DST arise in highly stressed colloids due to the creation of a stagnated network of particles interacting via friction with nearby mobile particles. Moreover, after each colloid reached equilibrium, its internal stresses plunged quickly, while the internal structure and particle motion dissipated much more slowly. The researchers note that these results may also provide new insights into other systems with slowly evolving dynamics, such as the compaction of granular particles under vibration or the compaction of crumpled sheets under stress. – Philip Koth

Read more on APS website

A Deeper Look into Emergent Magnetism at Interfaces

A Deeper Look into Emergent Magnetism at Interfaces

Recently, a research team led by Alexander Gray from Temple University shed new light on interfacial ferromagnetism in superlattices—i.e., multilayer structures composed of thin antiferromagnetic and paramagnetic layers. Their findings offer detailed insights into the electronic and structural factors influencing atomic-level interactions at magnetic interfaces.

“Nanoscale control of interfacial magnetic phenomena is central to spintronic device innovation,” said Gray. “Experiments using polarized x-rays get us closer to that goal by allowing us to extract depth-resolved magnetic profiles from stacks of alternating magnetic layers.”

At Advanced Light Source (ALS) Beamline 4.0.2, the team probed superlattices of antiferromagnetic CaMnO₃ and paramagnetic CaRuO₃ using x-ray resonant magnetic reflectivity (XRMR) together with x-ray magnetic circular dichroism (XMCD). When these techniques are combined, they can provide sensitivity to magnetization direction, elemental composition, and (by varying the x-ray incidence angle) sample depth.

Graduate student Jay Paudel, who led the measurements and data analysis and is now a postdoctoral scholar at the ALS, along with ALS Beamline Scientist Christoph Klewe, discovered that interfacial ferromagnetism exhibits an asymmetric distribution and may extend beyond the interfacial layer, suggesting more complex interfacial behavior than previously recognized.

“These results challenge previous assumptions by demonstrating that interfacial magnetism can span multiple unit cells and that the alternating interfaces are not magnetically symmetric, as confirmed independently by both depth-resolved and depth-averaged x-ray resonant magnetic measurements,” said Paudel.

Density functional calculations from Nicola Spaldin’s group at ETH Zurich identified the driving force behind this phenomenon as a double-exchange mechanism facilitated by charge transfer from Ru to Mn across the interface. Furthermore, the calculations revealed that oxygen vacancies significantly influence the magnitude of interfacial magnetic moments, offering a potential method to manipulate interfacial ferromagnetism.

“We are seeing more and more that defects such as oxygen vacancies, which we used to think of as a nuisance, can actually be used as a design tool to engineer functionalities such as magnetism at interfaces,” said Spaldin. Samples for these experiments were grown using pulsed laser deposition by Jak Chakhalian’s group at Rutgers University.

The study enhances our understanding of interfacial magnetism, presenting practical strategies for controlling magnetic interfaces and fostering future innovations in magnetic storage and spintronic technologies.

Read more on ALS webite

From Sequence to Structure: A Fast Track for RNA Modeling

From Sequence to Structure: A Fast Track for RNA Modeling

In Biology 101, we learn that RNA is a single, ribbon-like strand of base pairs that is copied from our DNA then read like a recipe to build a protein. But there’s more to the story. Some RNA strands fold into complex shapes that allow them to drive cellular processes like gene regulation and protein synthesis, or catalyze biochemical reactions. We know that these active molecules, called non-coding RNAs, are present in all life forms, yet we’re just starting to understand their many roles – and how they can be harnessed for applications in environmental science, agriculture, and medicine.

To study – and potentially modify – the functions of non-coding RNAs, we need to determine their structure. Scientists from Lawrence Berkeley National Laboratory (Berkeley Lab) and the Hebrew University of Jerusalem have developed a streamlined process that predicts the structure of an RNA molecule down to the atomic level. Members of the research community can come to Berkeley Lab’s Advanced Light Source (ALS) user facility knowing nothing more than the molecule’s nucleotide sequence and get a structure, or they can do it themselves using the team’s open-source software.

“We were looking at the bigger picture with structure prediction, like how we can go from A to Z rather than working on A, B, and D. That’s what we try to do at Berkeley Lab, make it user friendly,” said Michal Hammel, a staff scientist in Berkeley Lab’s Molecular Biophysics and Integrated Bioimaging (MBIB) division. Hammel co-developed the process, called SOlution Conformation PrEdictor for RNA (SCOPER), with MBIB colleague Scott Classen and Hebrew University collaborators Dina Schneidman-Duhovny and Edan Patt.

A paper describing SCOPER was recently published in Biophysical Journal.

Historically, it has ranged between difficult to impossible to accurately determine the three-dimensional atomic blueprint of a folded RNA because they rarely convert into a neat crystalline form to be imaged with X-ray crystallography. And because the twists and folds of the RNA strand move around as the molecule functions, there are actually multiple correct structures.

In recent years, artificial intelligence (AI) tools like AlphaFold have become very accurate at generating protein structure predictions based on amino acid sequence, making life a lot easier for scientists worldwide and greatly accelerating the pace of drug discovery. These algorithms have been expanded to RNA structures, but the accuracy remains middling. Getting a reliable model currently involves combining the outputs of multiple computational tools and imaging data. It’s a long process, and still fraught with uncertainty.

SCOPER has simplified it significantly. Say you want to study a new RNA: First, put the nucleotide sequence into one of the open-source, AI-based structure prediction tools available today. Then, take your sample to a small angle X-ray scattering (SAXS) facility for characterization. Better yet, let Hammel and his colleagues at the ALS’s SAXS beamline get that data for you.

Take the SAXS data and predicted structures, and put them through SCOPER’s pipeline. The first step uses an existing program to generate possible flexible arrangements of the RNA from the predicted static structures. Next, a new machine learning program, developed and trained on existing atomic structures by Patt, refines the structures by adding the placements of magnesium ions. Inside cells, positively charged magnesium ions interact with negatively charged RNAs to keep them folded stably. Their presence also helps elucidate structure when using SAXS.

Next, SCOPER generates simulated SAXS data representing the theoretical structures and compares them with the real-world SAXS data to determine which structure is correct.

Read more on ALS website

Image: These renderings show RNA structures that were used to evaluate the accuracy of the new SCOPER process. The AI-generated initial structure predictions based on sequence (blue) is pictured with the refined predicted structure generated by SCOPER (red), which includes the placement of magnesium ions (violet). 

Credit: Michal Hammel/Berkeley Lab

Aluminium made visible

Aluminium made visible

Zeolites are highly porous substances that facilitate numerous reactions in the chemical industry. In collaboration with the J. Heyrovský Institute of Physical Chemistry in Prague, PSI researchers have succeeded for the first time in precisely determining the position of the aluminium atoms in the zeolite lattice – an important step on the path to tailor-made catalysts. The study has now been published in the journal Science.

In cat litter they absorb unpleasant odours; in detergents they soften the water, protecting washing machines; and in refineries they help in the production of petrol – zeolites are used in many different places. We encounter them in our daily lives, and they are the most frequently used catalysts for promoting chemical reactions in industry. 

Their many useful properties stem from their porous, lattice-like structure. Silicon and aluminium atoms are linked by oxygen atoms to form a crystalline framework with numerous small pores and channels. Zeolites can capture molecules from gases or liquids, hold on to them and help to convert them into other molecules. But it is only now that PSI researchers have managed to draw a more precise picture of a zeolite structure: they have located the position within the lattice of the aluminium atoms that trigger the chemical reactions.

“Zeolites are extremely important materials, but we still don’t fully understand how they work,” says Jeroen van Bokhoven of PSI’s Center for Energy and Environmental Sciences. Previous methods were able to determine the position of the atoms in the lattice but could not distinguish aluminium from silicon. The aluminium atoms play a particularly important role, however: they form the active sites that allow certain reactions to take place. This is why scientists are particularly interested in locating them. 

The exact position of the aluminium atoms determines how effective the zeolite in question is as a catalyst and for which chemical reactions. Different zeolite structures are used for different reactions. The PSI researchers used their method to investigate the zeolite ZSM-5, a particularly important industrial catalyst with an unusually complex structure. “We reckoned that if we could do this with ZSM-5, the other zeolites wouldn’t be a problem,” says Jeroen van Bokhoven.

The SLS as a large microscope

The question of where exactly the aluminium atoms are located in the zeolite structure has long vexed scientists. “The new method we have developed solves a problem that previously seemed unsolvable,” says Przemyslaw Rzepka, first author of the study. Rzepka, who used to work with Jeroen van Bokhoven at PSI as a postdoc, is now a scientist at the J. Heyrovský Institute of Physical Chemistry in Prague. 

Until now, scientists have used ordinary X-rays to look inside zeolites and learn about the structure of their pores and channels. The X-rays are scattered by the atoms and the resulting diffraction pattern allows conclusions to be drawn about the three-dimensional structure of the material. The problem is that the elements silicon and aluminium are right next to each other in the periodic table, and this means that in experiments using ordinary X-rays they look more or less identical. Spectroscopic methods, on the other hand, rely on the way a material absorbs radiation or alters it. Because aluminium and silicon absorb radiation differently, the two types of atoms can be distinguished – however, such methods cannot determine their positions in space, only the number and type of atoms in a material.

The PSI scientists’ solution was to combine the two techniques. They directed soft X-rays, which have comparatively low energies, at the materials at the Swiss Light Source SLS. “The pattern created when the X-rays are scattered by the material tells us the position of the atoms. We then examine these positions using spectroscopic methods to identify the particular type of atom that is sitting there,” explains Przemyslaw Rzepka. 

This clever combination was made possible by the unique X-ray diffractometer for soft X-rays at the SLS Phoenix beamline. The researchers were able to see, for the first time, a difference between silicon and aluminium atoms and determine the exact location of the active sites where the reaction takes place.

Read more on PSI website

Image: Jeroen van Bokhoven (left) and his team at the Paul Scherrer Institute PSI in Villigen are carrying out research into zeolites. His research group has succeeded for the first time in determining the position of the aluminium atoms that are crucial to the catalytic properties of the materials. This was possible thanks to the Swiss Light Source SLS, where scientist Thomas Huthwelker (right) works.

Credit: Paul Scherrer Institute PSI/Markus Fischer

Closing the door on colds and flu

Closing the door on colds and flu

First-of-its-kind structural data about protein family is key for drug discovery

New research by scientists at the University of Toronto and the Structural Genomics Consortium has deepened our understanding of how viruses like the flu, common cold, and COVID-19 get into cells in human airways.

Using the Canadian Light Source at the University of Saskatchewan, the researchers identified for the first time the crystal structures of a human protein (TMPRSS11D) that viruses use as a doorway into our body.

Understanding how viruses use our proteins to gain entry into our cells will help researchers develop better ways to stop infections in their tracks.

“This paper is really the stepping stone for building out more effective antiviral agents,” says lead author Bryan Fraser, a University of Toronto postdoctoral researcher at the Structural Genomics Consortium.

“We’re using the structure-based information that we’ve gained here to guide us in improving molecules that we hope will become drug candidates.”

Knowing the crystal structure of this “doorway” protein, says Fraser, is key to finding helpful drugs to stop coronavirus and influenza viruses, because it is very similar to other important proteins in the human body.

“Many of the important proteins for coagulation that are present in your blood look a lot like the TMPRSS proteins,” Fraser explains.

Successfully drugging subtle features on the TMPRSS proteins that are not present in coagulation proteins can be the difference between stopping infections and interfering with how wounds heal.

“The major challenge in our field is finding really effective compounds or drug candidates that show they’re selective for the target you’re interested in, and don’t block those other essential functions,” says Fraser.

While precise targeting is a challenge, the promise of these proteins as drug targets is immense.

Read more on CLS website

Breakthrough in Ultra-Thin Memory Devices! Taiwan’s First 2D Ferroelectric Material Unveils a New Era

Breakthrough in Ultra-Thin Memory Devices! Taiwan’s First 2D Ferroelectric Material Unveils a New Era

With long-term support of the National Science and Technology Council and the Ministry of Education, a research team composed of members from the National Synchrotron Radiation Research Center (NSRRC), National Cheng Kung University (NCKU), and Tamkang University published a major breakthrough in Advanced Materials on April 16, 2025. The team successfully developed a reliable method for stacking-controlled van der Waals (vdW) heteroepitaxy, demonstrating for the first time the growth of an epitaxial ferroelectric hexagonal boron nitride (h-BN) ultra-thin film on graphene. This material exhibits homogeneous out-of-plane ferroelectricity that can be switched via interlayer sliding, signaling a promising advancement for next-generation high-efficiency, micro-scaled electronic devices and highlighting Taiwan’s leading role in the competitive field of 2D ferroelectric materials.

“Ferroelectricity” refers to a property in which a material exhibits spontaneous electric polarization that can be reversed by an external electric field—essentially functioning like an “electrical switch” to precisely control current flow. This characteristic makes ferroelectric materials ideal for use in memory devices, sensors, and low-power computing components. However, conventional ferroelectric materials are typically too thick, posing challenges for device miniaturization. h-BN, often referred to as “white graphene,” is a highly stable, ultra-thin 2D material with a symmetric hexagonal structure similar to graphene. Due to this symmetry, h-BN does not naturally exhibit ferroelectricity. Recent advances, however, have shown that such properties can be engineered in h-BN by manipulating its stacking arrangement or by integrating it with other 2D materials.

After years of dedicated research, a team led by Prof. Chung-Lin Wu (NCKU) achieved a breakthrough. Using plasma-assisted molecular beam epitaxy (PA-MBE), they first grew high-quality single-crystalline graphene on a silicon carbide (SiC) wafer, then precisely stacked h-BN layers atop it. This process resulted in an asymmetric stacking configuration of h-BN on the naturally formed Moiré-patterned graphene/SiC interface, inducing switchable out-of-plane polarization—a hallmark of ferroelectric behavior. Their technique not only overcomes a long-standing technological bottleneck but also enables wafer-scale precision control over thin-film growth with exceptional uniformity and stability.

Dr. Cheng-Maw Cheng, Head of the Scientific Research Division at NSRRC, emphasized that this achievement was made possible through close interdisciplinary collaboration across multiple universities. Using angle-resolved photoemission spectroscopy (ARPES) at the Taiwan Light Source (TLS), the team confirmed the evolution of band structure and interfacial polarization in the layer-controlled, multilayer h-BN/graphene heterostructure. Meanwhile, the theoretical simulations led by Prof. Hung-Chung Hsueh (Tamkang University) verified the electronic band properties of asymmetrically stacked multilayer h-BN. Subsequently, Prof. Yi-Chun Chen (NCKU) employedscanning probe microscopy (SPM) to confirm that the polarization states in these ultra-thin h-BN films are both stable and reversible—performance characteristics highly desirable for ferroelectric memory applications. The asymmetric stacking configuration and robust ferroelectric behavior of these h-BN films make them a promising platform for future volatile memory devices and AI hardware, particularly in high-speed, low-power matrix–vector operations. Moreover, their excellent structural compatibility with other 2D materials, such as graphene and molybdenum disulfide (MoS₂), enables the design of stacked heterostructure chips—paving the way for new breakthroughs in Taiwan’s semiconductor and optoelectronic industries.

Notably, the first author of this publication, Dr. Sheng-Shawn Wong, was awarded a Ph.D. scholarship sponsored by NSRRC. During his graduate studies, he demonstrated a strong commitment to advanced materials research and made full use of NSRRC’s multidisciplinary facilities to conduct his experiments. This publication represents one of his major research achievements and exemplifies the impact of interdisciplinary collaboration among scientists across different institutes. It also highlights the vital role of young physicists in Taiwan and their growing presence in the global scientific community.

Read more on NSRRC website

Watching superheated silver nanoparticles bubbling

Watching superheated silver nanoparticles bubbling

Matter under extreme conditions, especially at extreme temperatures and pressures, plays an important role in many fields. These range from astrophysics and geology over inertial fusion reactor studies to applied research on material processing by laser ablation. Due to the complex behaviour of matter under such conditions the underlying interactions are not yet fully understood. In recent years isolated nanoparticles, which form well-defined crystalline structures at lower temperatures, have proven to be suitable test objects for the study of such questions.

A team of researchers including DESY scientists around Daniela Rupp (ETH Zurich), Thomas Möller (TU Berlin) and Bernd v. Issendorff (Univ. Freiburg), as well as several groups from Univ. Rostock (Ingo Barke, Karl-Heinz Meiwes-Broer, Thomas Fennel), has applied time-resolved soft X-ray diffraction at the CAMP endstation at FLASH to study the dynamics of superheated silver nanoparticles in a laser pump – FEL probe experiment. They observed that silver nanoparticles, when strongly laser-heated via their plasmon resonance, exhibit a wide range of phenomena, from melting over cavitation-induced bubble-like expansion to explosion, as a function of the excitation strength. “Depending on the heating conditions and the temporal evolution, we could identify different classes of diffraction images, stemming from faceted, round, hollow, fragmenting or sometimes finally exploding nanoparticles”, Alessandro Colombo (ETH Zurich), one of the three first authors, explains.

Read more on DESY website

Image: Diffraction image of a hollow silver nanoparticle (left) measured at FLASH, along with its reconstruction (top right) and a corresponding picture from MD simulations (bottom right).

Credit: T. Reichenbach, Univ. Freiburg