Catalysis research with the X-ray microscope at BESSY II

Catalysis research with the X-ray microscope at BESSY II

Contrary to what we learned at school, some catalysts do change during the reaction: for example, certain electrocatalysts can change their structure and composition during the reaction when an electric field is applied. The X-ray microscope TXM at BESSY II in Berlin is a unique tool for studying such changes in detail. The results help to develop innovative catalysts for a wide range of applications. One example was recently published in Nature Materials. It involved the synthesis of ammonia from waste nitrates.

Ammonia (NH3) is a basic component of fertilisers and is critical to agricultural productivity around the world. Until now, ammonia has been synthesised industrially using the Haber-Bosch process, which is energy intensive and produces significant amounts of greenhouse gases that drive climate change. With the development of alternative methods, ammonia could be produced with significantly lower greenhouse gas emissions.

Better catalysts reduce emissions for Ammonia production

There are some promising approaches. For example, a team at the Fritz Haber Institute has been investigating a catalyst based on nanocrystalline copper oxide. During the catalytic reaction, an increasing proportion of these nanocrystals transformed into metallic particles of pure copper. The morphological changes were documented under the transmission electron microscope (TEM), but to gain insights into the chemical processes during the reaction, the FHI team collaborated with the group of Prof. Gerd Schneider at HZB.

Read more on HZB website

Creating circuit diagrams of the brain

Creating circuit diagrams of the brain

Adrian Wanner aims to map the brain’s architecture. Doing this will allow us to better understand neurodegenerative diseases like Alzheimer’s.

Do you know this situation? You are standing in the kitchen and suddenly don’t remember why you went in there in the first place. Working memory is at fault here. It is supposed to keep information available for us for a period of several minutes. “If it isn’t working properly, it can lead to situations just like this one, where you forget whatever it was you wanted to do,” explains Adrian Wanner, a neurobiologist at the Laboratory of Nanoscale Biology at the PSI Center for Life Sciences (CLS).

In everyday life, situations like this might be unpleasant, but tend to be ultimately harmless. For some people, however, they may indicate a more serious underlying issue, as Adrian Wanner explains: “In the case of Alzheimer’s, working memory is often the first thing to be affected. Long before pathological changes like protein deposits in the brain become clearly visible, patients experience this type of forgetfulness.” Understanding working memory and its structure in detail could thus contribute to better comprehension of the terminal illness Alzheimer’s.

Activity maps and circuit diagrams

In order to reconstruct what exactly happens when the working memory keeps information available, Wanner uses two methods. “First, we create activity maps of brain cells,” the neurobiologist explains. “In these diagrams, the neurons that are activated by a particular action light up in colour.” 

The researchers then try to find out how the individual neurons in this area are linked. “It’s like a circuit diagram for a computer,” says Wanner – but with biological synapses instead of electrical connections. Most brain regions and functions have not yet been mapped by way of such a circuit diagram that describes how information is processed: “Does information go directly from point A to point B to point C or are there cross connections or feedback loops in between that move it a step back?” 

There are various, often conflicting theories on which paths the brain activates when it processes and then stores information. Adrian Wanner wants to use empirical data to determine which model best reflects reality. He wants to observe which neurons are active during tasks for which working memory is important. He then maps the way in which these neurons are interlinked to create a detailed circuit diagram. “This way, we can track exactly what is happening in the brain at this point in time.”

The working memory at work

For his research, Adrian Wanner works with mice. “In terms of structure and function, their brains are similar to those of humans’,” he explains. “This is why they can also develop forms of dementia and we can analyse how healthy animals differ from sick ones.”

In order to analyse a mouse’s working memory, the neurobiologist sets it a task where the mouse has to remember information for a few seconds. First, the mouse learns how to move around in a virtual environment, similar to a computer game. To do this, the animal watches a screen and runs along a virtual corridor. At the beginning of the corridor, the mouse is shown a specific pattern, for example a checkerboard pattern. It must then remember this pattern. 

After a few metres, the corridor forks into a left-hand and a right-hand path. Once the mouse arrives at this point, a pattern is displayed at each path, a line pattern on the right and a checkerboard pattern on the left, for instance. Now, the mouse has to recall: “Aha! There was also a checkerboard pattern at the beginning of the corridor.” If it turns left at the virtual fork, it receives a real reward in the form of food. “It is precisely during this period, when the mouse is no longer looking at the pattern and is running along the corridor, that it must keep the information available – its working memory is active.”

While the mouse is playing this memory game, Wanner and his team are imaging the activity in its brain. By comparing these images to circuit diagrams of the brain, they can determine the rules according to which the neurons are linked in order to keep this piece of information in working memory. “In fact, brain activity differs depending on the pattern that we show the mouse. A checkerboard pattern causes different cells to activate in a different sequence than a line pattern.”

Read more on PSI website

Image: Tiny section of a mouse brain: a few dozen nerve cells with their synapses are shown, and thus only a fraction of the 100 000 cells that cavort in a cubic millimetre of brain.

Credit: MICrONs Consortium et al.

Advanced materials research in microgravity earns NASA recognition

Advanced materials research in microgravity earns NASA recognition

Key Points

  • Collaborative research has advanced an understanding of how colloidal clusters form and behave in microgravity
  • The microgravity environment aboard the ISS minimised sedimentation and convection, providing a unique opportunity to observe the pure self-assembly of particles with unique optical properties
  • Structural analyses were later conducted using neutron scattering instruments at the Australian Centre for Neutron Scattering

A pioneering study led by Professor Junpei Yamanaka of Nagoya City University and an international team that included ANSTO has delivered transformative insights into the behaviour of colloidal particles under microgravity. 

Conducted aboard the International Space Station (ISS), this research has not only been prominently featured in NASA’s 2024 Annual Highlights of Results from the International Space Station Science but also promises to reshape future material technologies—including revolutionary optical devices and even the elusive cloaking devices reminiscent of science fiction.

Colloidal clusters—aggregates of nano- and micrometre-sized particles suspended in a fluid—play a pivotal role in various industrial and scientific applications. 

“On Earth, gravity-induced effects, such as sedimentation and convection, can obscure the intrinsic properties of these clusters, hindering our ability to study their natural assembly,” explained Principal Instrument Scientist Assoc Professor Jitendra Mata at ANSTO’s Australian Centre for Neutron Scattering. 

“However, the microgravity environment aboard the ISS minimises these disturbances, providing a unique opportunity to observe the pure self-assembly of particles.”

In a specialised experimental setup, the research team mixed oppositely charged colloidal particles in an aqueous solution, allowing them to cluster in of the absence of gravity, providing opportunity to understand fundamental science of association. 

Once these structures were formed, they were immobilised in a gel using ultraviolet (UV) light curing—a process that preserved the delicate architecture of the clusters for subsequent analysis back on Earth. 

Optical microscopy revealed that even minimal gravitational effects post-return can significantly influence the formation of colloidal structures, underscoring the value of space-based research.

This landmark research exemplifies robust international collaboration. The groundwork for the experiments began in Japan in 2018, with critical contributions from Nagoya City University, Japan Space Forum, Advance Engineering Services, and the Japan Aerospace Exploration Agency (JAXA). 

Structural analyses were later conducted in partnership with A/Prof Mata using the Small-angle neutron scattering instrument Quokka and Ultra-small neutron scattering instrument Kookaburra.

“This collaboration has been instrumental in advancing our understanding of how colloidal clusters form and behave in microgravity,” he said.

The significance of these experiments extends well beyond fundamental science. Colloidal clusters have been shown to scatter light in the visible to near-infrared spectrum, making them highly promising for applications in photonics, optical communications, and laser technologies. 

Their unique light-manipulating properties hint at future breakthroughs, including the potential development of advanced optical materials and even cloaking devices—innovations that capture the imagination much like the futuristic technologies portrayed in Star Trek.

Moreover, the ability to study these clusters in a space-based environment opens up new avenues for designing better materials. “

Read more on ANSTO website

BESSY II: Magnetic ‘microflowers’ enhance local magnetic fields

BESSY II: Magnetic ‘microflowers’ enhance local magnetic fields

A flower-shaped structure only a few micrometres in size made of a nickel-iron alloy can concentrate and locally enhance magnetic fields. The size of the effect can be controlled by varying the geometry and number of ‘petals’. This magnetic metamaterial developed by Dr Anna Palau’s group at the Institut de Ciencia de Materials de Barcelona (ICMAB) in collaboration with her partners of the CHIST-ERA MetaMagIC project, has now been studied at BESSY II in collaboration with Dr Sergio Valencia. Such a device can be used to increase the sensitivity of magnetic sensors, to reduce the energy required for creating local magnetic fields, but also, at the PEEM experimental station, to study samples under much higher magnetic fields than currently possible.

Dr Anna Palau from the Institut de Ciencia de Materials de Barcelona (ICMAB) has developed a special metamaterial that looks like tiny flowers under the scanning electron microscope. The ‘petals’ consist of strips of a ferromagnetic nickel-iron alloy. The microflowers can be produced in various geometries, not only with different inner and outer radii, but also with variable numbers and widths of petals. This flower-shaped geometry causes the field lines of an external magnetic field to concentrate in the centre of the device, resulting on a greatly intensified magnetic field.

Magnetic metamaterials

‘Metamaterials are artificially produced materials with microstructures whose dimensions are smaller than the electromagnetic or thermal waves they are designed to manipulate,’ explains Anna Palau. The physicist is working on magnetic microstructures that can be used in data storage, information processing, biomedicine, catalysis and magnetic sensor technology. By using these metamaterials, the sensitivity of magnetic sensors could be highly increased, as the magnetic field to be detected would be amplified at the center of these systems.

Read more on HZB website

Image: The magnetic microstructure of the nickel-iron alloy leads to a compression of the field lines in the centre.

Credit: A. Palau/ICMAB

A new 100 picosecond time-resolved technique images surface acoustic wave devices

A new 100 picosecond time-resolved technique images surface acoustic wave devices

Beamline ID01 can now study Surface Acoustic Waves (SAW) devices at operando conditions thanks to a new technique called stroboscopic full-field diffraction X-ray microscopy at the ESRF. Their results open the doors to more experiments with these systems and on electronic circuits and devices in general. They are published in Nature Communications.

A Surface Acoustic Wave (SAW) device is an electronic device that uses sound waves traveling along the surface of a material (usually a piezoelectric crystal) to process, filter or transmit signals. Their applications are wide, and include mobile phones, Wi-Fi, GPS, and 5G networks to filter and separate different frequency bands, touchscreens, sensors in the automotive and aviation industry, biosensors. They are also promising devices in nanoscale applications, such as quantum communication.

Because they are highly sensitive, durable, compact and cheap, there is a lot of ongoing research into understanding how to optimise their structure. This needs a deep understanding of energy conversion and loss mechanisms taking place in the device.

In SAW devices, electrical energy is converted into sound waves using interdigital transducers. These are tiny comb-shaped metal electrodes placed on a piezoelectric crystal. One set of electrodes is grounded, while the other receives an alternating voltage, causing the crystal’s surface to strain or deform. This vibration creates an acoustic wave that travels at several kilometers per second. These waves have extremely high frequencies (hundreds of MHz to GHz), far too fast for even the best high-speed cameras to capture.

However, now a team led by ESRF scientists has developed a technique called stroboscopic full-field diffraction x-ray microscopy on beamline ID01, which allows them to study the dynamic strain in SAW devices. “Today the spatial resolution at the ESRF’s ID01 is about 100nm and we have a time resolution in the storage ring of 100 picoseconds: this is practically the speed of sound . This means that we can image sound unblurred”, explains Tobias Schulli, scientist in charge of ID01 and co-corresponding author of the publication.

The experiments showed that there was an unexpected acoustic loss in a resonator device tested. It proved that propagating modes leak elastic energy away from the resonator. The high sensitivity of X-ray diffraction for changes in atomic distances by 1/100 000 together with the high time and spatial resolution available on ID01 represent the only available technique to detect and quantify such phenomena.

Read more on ESRF website

High-speed snapshots reveal hidden details of catalysis

High-speed snapshots reveal hidden details of catalysis

Developments in time-resolved catalysis research opens a long-awaited opportunity to revisit catalytic reactions that have been subject to scientific debate. In this recent publication, the newly developed method has been used to settle the mechanism for carbon monoxide transformation to carbon dioxide over a platinum catalyst. The result is an important step towards optimisation of catalysts.

The conversion of carbon monoxide to carbon dioxide with the help of a platinum catalyst is one of the most famous catalytic reactions and one that’s been studied for decades. It happens every day in every car catalytic converter to prevent the emission of highly toxic carbon monoxide. The mechanism for the reaction has, however, been subject to a lot of debate. 

It was a big success when, a few decades ago, carbon monoxide oxidation on platinum could be studied with a suite of surface science methods under idealistic conditions: ultrahigh vacuum and low temperatures. The studies suggested that oxygen bound to metallic platinum is the active species in the reaction. However, at the beginning of the 2000s, new tools and experimental methods that could probe the same reaction under realistic conditions, so-called operando, at elevated pressures and temperatures, started to appear. The results suggested a new candidate for the active species, platinum oxide, and the big debate started.

“The main challenge with such a materials system, however, is that although the oxide formation is indeed favourable under operando conditions, its presence does not imply reactivity. With studies done under equilibrium conditions, there is actually no way of telling,” says Andrey Shavorskiy, beamline scientist at the HIPPIE beamline and one of the authors of the study.

Dynamic and time-resolved surface studies have, with faster detectors and brighter synchrotrons, become a hot research topic. Ambient-Pressure X-ray Photoelectron Spectroscopy (AP-XPS) is a method that, through clever engineering, lets researchers do spectroscopic surface measurements under pressure conditions that otherwise would not be compatible with this type of study. It is especially important for catalysts where the function is closely connected to the operating pressure. Combining the two, time resolution with AP-XPS, at the HIPPIE beamline, shows promise for a new era of surface science studies.

“The main difference between all past studies and what we have done at HIPPIE was that we decided to follow the reaction as it happens in real-time. In collaboration with the Synchrotron Radiation Research Division of the Lund University Physics Department, we have developed a suite of time-resolved tools that allow us to look at chemical reactions on surfaces under operando conditions with high enough time resolution to detect the formation of intermediate species. The key parts of the development are the ability to initiate the reaction on the whole sample at the same time with a very fast valve that was developed at MAX IV and the ability to follow the response of the system under such a perturbation with a very high time resolution. We have pushed the AP-XPS experiment to its extreme and can obtain high-quality data with 20–40 µs time resolution. This has never been achieved before with chemical perturbations in an AP-XPS setup,” says Shavorskiy.

The researchers were able to follow the reaction closely and found the actual reaction mechanism, which, with a less exact method, could have been easily missed in overlapping signatures. They foresee that the method will be very attractive to their colleagues in the catalysis and surface science communities in the future.

“When we analyzed the collected spectra, we were able to identify a small region in time when the formation of oxygen bonded to metallic platinum was delayed with respect to the formation of platinum oxide. The reason for this, we reckon, is its very high activity. It never lives long enough on the surface to be detected as it is immediately consumed in the reaction. On the other hand, the platinum oxide is much less reactive, so it can stay on the surface unreacted, and we can detect it. 

Read more on MAX IV website

New material moves seawater batteries step closer to primetime

New material moves seawater batteries step closer to primetime

As the world makes more use of renewable energy sources, new battery technology is needed to store electricity for the times when the sun isn’t shining, and the wind isn’t blowing.

“Current lithium batteries have reached their limitations in terms of energy storage capability, life cycle, and safety,” says Xiaolei Wang, a professor of chemical engineering at the University of Alberta in Edmonton. “They’re good for applications like electric vehicles and portable electronics, but they’re not suitable for large-scale grid-level energy storage.”

With the help of the Canadian Light Source at the University of Saskatchewan, Wang and his team are developing new technologies to help make grid-level aqueous batteries that can use seawater as an electrolyte. Aqueous batteries can be safer, cheaper, and more environmentally friendly to make and dispose of than lithium-ion batteries, but their development has so far been limited by a lack of a good material to make a decent anode (the part of the battery where electricity flows out).

Wang’s team developed a material made of polymer nanosheets and carbon nanotubes that is suitable for storing a variety of different types of ions, including those found naturally in seawater. These anodes are thicker than previous ones, so have a high capacity for storing energy, and are extremely durable so they can last a long time – up to 380,000 charging cycles in some cases – and they can operate under extreme conditions such as fast charging and discharging, or at low temperatures, says Wang.

The ultrabright synchrotron light at the CLS was vital in understanding the microstructure of the anode material and its electrochemical behaviour. “The success of our project could not have been realised without CLS,” says Wang.

Read more on CLS website

Shaping the future of antibiotic design

Shaping the future of antibiotic design

Bacteria and fungi have been engaged in molecular warfare for millions of years. This means they have perfected ways to get past the defenses of other organisms and have also devised ways to keep them out. This arms race was revealed in 1928 when Alexander Fleming returned from his holidays to discover a petri dish of bacteria in which a fungus had started to grow and was killing the bacteria around it. He immediately realized the potential value of these antibiotic molecules to humans for curing disease. 

Now, however, our widespread use of natural antibiotics has led to the emergence of drug-resistant bacteria and an urgent need to develop some new molecular weapons of our own. With that in mind, a research group from the University of Michigan conducted a substrate-trapping study of bacterial enzymes that make an important class of antibiotics. The research provides important new information that will facilitate the design of new enzymes to make novel antibiotics that can overcome antibiotic resistance.

The group used the resources of the National Institute of General Medical Sciences and National Cancer Institute Structural Biology Facility (GM/CA) at beamlines 23-ID-B and 23-ID-D at the Advanced Photon Source, a U.S. Department of Energy (DOE) Office of Science user facility at DOE’s Argonne National Laboratory.

The research focused on bacterial thioesterase (TE) enzymes that perform a critical step in a synthetic pathway to make macrolide antibiotics such as erythromycin and pikromycin. These TE enzymes temporarily attach antibiotic precursors to a nucleophilic amino acid in the TE, check the structural integrity of the precursor substrates, and then convert them to either a) a cyclic lactone molecule via nucleophilic attack by an oxygen atom in the substrate, or to b) a linear final product via attack by a water molecule. Although the structures of five TE enzymes that generate various products have been solved, the process by which a product is cyclized or hydrolyzed is poorly understood. 

To get a clearer picture of the final step in the antibiotic synthesis process that might help researchers to understand the parameters needed to make new antibiotics, the team decided to use a technique called substrate trapping to visualize the moment of decision between cyclization and hydrolysis in different TE enzymes. They used a new substrate trapping technique that incorporates a non-natural amino acid into the active site in place of the natural serine or cysteine nucleophile. The bond attaching a substrate to serine or cysteine is unstable, but the non-natural amino acid traps the reaction intermediate as a stable amide group (see Figure). 

After testing five bacterial TE enzymes to see if they could successfully incorporate the substrate trap, two of substrate trapping proteins could be purified in sufficient amounts for further testing, one that makes erythromycin and one that makes pikromycin, both cyclic antibiotics. 

Read more on APS website

Image: Model of the thioesterase enzyme active site with the cyclic substrate (purple) snugly fitted into the catalytic site of the TE (yellow). The substrate trap is represented by the blue nitrogen atom that forms a stable bond between the enzyme and substrate, preventing the substrate from leaving the site so the reaction intermediate can be studied at the molecular level. The substrate nucleophilic oxygen atom (red) is at the left end of the substrate.

Credit: Rajani Arora and Vishakha Choudhary of the University of Michigan.

Explosive Prevention for 1,000km Next-Gen Battery!

Explosive Prevention for 1,000km Next-Gen Battery!

A solution to the gas-filling problem of the next-generation long-distance battery1) has emerged.
A team led by Professor Lee Hyun-wook of UNIST’s Department of Energy and Chemical Engineering has identified the cause of Oxygen generation in olig Lithium of a new anode material for batteries and presented material design principles to solve this problem.

Overlithium materials can theoretically store 30% to 70% more energy in batteries than before through high-pressure charging of 4.5V or higher. In terms of electric vehicle mileage, you can go up to 1,000 kilometers on a single charge. However, this material has a problem of increasing the risk of explosion as Oxygen (O-2) held inside the material is oxidized and released as gas (O2) during the actual high-pressure charging process.

The research team analyzed that Oxygen is oxidized near 4.25V, causing partial structural deformation and releasing Oxygen gas. They proposed an electrode material design method that fundamentally prevents the oxidation of Oxygen. This strategy involves replacing some of the transition metals2) of Lithium materials with transition metal elements with lower electronegativity.

The difference in electronegativity between the two metal elements causes the number of available electrons in the transition metal to increase, and Oxygen does not oxidize when electrons are concentrated around the highly electronegativity element. On the other hand, when the number of available electrons in the transition metal is insufficient, Oxygen gives electrons instead. It is oxidized to be discharged in the form of a gas.

The first author, Kim Min-ho (Currently a postdoctoral researcher at UCLA), explained “the difference between existing research that has focused on stabilizing Oxygen and preventing it from being discharged in the form of gas, whereas present research has focused on preventing the oxidizing process itself.”

In addition, this change in electron density increases the charging voltage through an Inductive Effect3), thereby increasing the high energy density attainable. Since the energy density is proportional to the number of available electrons and the charging voltage, it is possible to store more energy per unit weight of the battery to replace the transition metal. This phenomenon is similar to the principle that if there’s more water in the dam and the drop is more significant, more energy is stored.

The researchers experimentally confirmed the transition metal substitution strategy’s inhibitory effect on Oxygen oxidation. Accelerator-based X-ray analysis showed that the generation of Oxygen gas was significantly reduced when a part of Ruthenium was replaced with Nickel. Furthermore, they theoretically demonstrated that charge rearrangement occurs through density functional calculation (DFT).

This study was conducted by Professor Seo Dong-hwa of KAIST, Chung-Ang University, Pohang Accelerator Laboratory, Professor Yu Zhang Li of UCLA, UC Berkeley, and Lawrence Berkeley Research Institute. The accelerator-based X-ray analysis was conducted by Professor Jang Hae-sung of Chung-Ang University (Co-first author), and the DFT theoretical calculation was led by Dr. Lee Eun-ryul (Co-first author) of the Lawrence Berkeley Institute in the United States.

Professor Lee Hyun-wook said, “We presented the direction of material development to cathode material researchers by librarying technology through various experiments and theoretical analysis,” adding, “It will help to develop long-distance driving battery materials without explosions with increased energy density.”

The study was carried out with the support of the National Research Foundation of Korea (NRF)’s international cooperation and development project on source technology. The results were published online on Feb. 19 in ‘Science Advances’, a sister paper of the world-renowned journal ‘Science’ published by the American Science Association (AAAS).

Read more on PAL website

Breakthrough in next-generation polio vaccines

Breakthrough in next-generation polio vaccines

A more affordable, lower-risk vaccine could soon be possible following research conducted at Diamond’s electron Bio-Imaging Centre (eBIC).

Scientists have made significant progress in developing a more cost-effective and safer polio vaccine, something which is essential for the global effort to eliminate the disease. Polioviruses mainly affect children under five years of age, with some infections leading to irreversible paralysis and sometimes death.  

For the last three decades, the World Health Organization, which funded the study, has been focused on the worldwide eradication of polio. Since 1988, poliovirus cases have decreased by 99% and the possibility of eliminating this disease is on the horizon. The prospect of a new type of vaccine could play a significant part in this endeavour.

The research project looked at using virus-like particles (VLPs). These particles imitate the outer protein structure of the poliovirus but are hollow inside and do not contain any viral genetic material. This eliminates the risk of infection while still triggering an immune response. 

Researchers from the University of Leeds have been exploring how different types of cells – yeast, mammalian and plant cells – can be used to produce VLPs. Their findings, recently published in Nature, indicate that VLPs generated in yeast and insect cells can perform equally or better than the currently used inactivated polio vaccine (IPV).  

Peijun Zhang, director of eBIC, said:

Cryo-EM at eBIC enables scientists to determine the detailed 3D structure of VLPs, revealing how they resemble real viruses in shape and protein arrangement. This helps researchers optimise the design of VLP-based vaccines to ensure they trigger a strong immune response while remaining non-infectious.

The current polio vaccine (IPV) is relatively expensive to use as it requires a high level of biocontainment to minimise the risk of leaks of the live polio virus, which could lead to outbreaks. In contrast, the VLP simulated particles are non-infectious, therefore removing the need for bio-safety protocols.   

Professor Nicola Stonehouse, of the University of Leeds School of Molecular and Cellular Biology and one of the senior authors on the paper, said: “Any vaccine is only as effective as the number of children that it reaches. The key is to make vaccines universally accessible, as all children have a right to be protected from diseases such as polio, no matter where they live. VLPs would significantly contribute to vaccine equity.”

The plan to eradicate polio

The oral polio vaccine (OPV) contains a weakened vaccine-virus and its continued use could hinder the complete eradication of the disease. Once all strains of wild poliovirus strains are eradicated, the use of OPV will be phased out. This is because the weakened form of the virus in the OPV can sometimes mutate and cause variant forms. When the use of the OPV stops, the IPV will be the only available vaccine. However, its expensive manufacturing procedure make it unaffordable for lower-income countries, possibly leading to a reduction in vaccination rates.  

The virus-like particle (VLP) vaccines are the promising alternative, as with no viral genetic material, they are non-infectious and safer than traditional vaccines. They can also be engineered to be more stable, which maintains their effectiveness during storage or transportation. 

This could eventually lead to a more equitable access to vaccination, ensuring that countries that do not have suitable infrastructure can safely store and distribute the vaccine.  

VLP vaccines have already been successfully used for other diseases, like hepatitis B and human papillomavirus (HPV), and researchers have been working for over a decade to successfully apply this technology to help eradicate polio.  

The international research collaboration includes researchers from the University of Oxford, the Medicines and Healthcare products Regulatory Agency (MHRA), the John Innes Centre, the Pirbright Institute, the University of Florida and the University of Reading. All of the cryo-EM data was collected at eBIC.  

Read more on Diamond website

Manipulating polarons in thin-film tellurene shows promise for advanced electronics

Manipulating polarons in thin-film tellurene shows promise for advanced electronics

Polarons are quantum entities that arise in crystalline solids due to interactions between electrons and quantized lattice vibrations (phonons). Characterizing polaron behavior is important to scientists because they can play an important role in solid-state phenomena such as thermoelectricity, ferroelectricity, magnetoresistance, and high-temperature superconductivity. While polarons have been extensively investigated in bulk (3D) lattices, few investigations have probed polarons in one- and two-dimensional crystalline structures.

In this research, scientists probed flakes of tellurene with thicknesses of less than 20 nanometers, using a technique called extended X-ray absorption fine structure (EXAFS) spectroscopy. This work was carried out at beamline 20-BM of the Advanced Photon Source, a U.S. Department of Energy (DOE) Office of Science user facility at DOE’s Argonne National Laboratory.

The EXAFS measurements characterized the structural changes in tellurene as flake thickness decreased, suggesting a transition from large-to-small polarons at a thickness of 10 nanometers. The experimental results gleaned from EXAFS, along with Raman spectroscopy data, were buttressed by theoretical insights and quantitative modeling that together provide a highly developed picture of polaron behavior as tellurene thickness varies.

These new findings will aid in developing the significant potential of tellurene for various technological applications, such as use in advanced transistors and sensing devices, and as a superconducting material. More broadly, these findings will also contribute to a deeper understanding of polaron behavior in other thin-film materials.

Tellurene is a thin-film semiconductor composed of helical chains of tellurium (Te) atoms. Because these helical chains interact through weak forces, it is sometimes referred to as a “quasi-one-dimensional” material. Tellurene is appealing for use in a variety of electronic applications due to its P-type semiconductor properties, which make it suitable for creating PN junctions when paired with N-type materials.

Tellurene samples were synthesized using a hydrothermal method that immerses the source materials in a closed bath of water-based solution subjected to high heat and pressure. Tellurium atoms subsequently precipitate out of the aqueous solution onto a substrate, forming tellurene flakes of varying thicknesses. Figure 1A shows a typical flake about 10 micrometers across and 9 nanometers thick. Fig. 1B is an electron microscope image of tellurene.

Phonons can exist in thin films as well as bulk 3D crystals. Just as a photon of light is a discrete unit (quantum) of electromagnetic energy, a phonon is the quantum of vibrational energy of a crystalline lattice. In tellurene, phonons can be polarized, meaning they vibrate along a particular direction, due to tellurene’s crystalline structure (Fig. 1C).

When a phonon strongly interacts with an electron in a crystalline lattice, a quasiparticle called a polaron is formed. A quasiparticle is not an actual particle, like an atom or electron, but rather a collective excitation. However, since the interaction between an electron and phonon is quite complex, treating polarons as quasiparticles makes them easier to describe both mathematically and conceptually.

Read more on APS website

Image: Optical image (A) of a tellurene flake. Superimposed lines indicate lattice structure, while inset indicates the depth profile. A scanning transmission electron microscopy (STEM) image of tellurene (B), with lavender lines highlighting lattice structure. Red arrows in panel (C) indicate lattice vibrations of individual tellurium atoms (purple spheres). These unbalanced vibrations produce polarized phonons. Plot of polaron size versus flake thickness in (D) shows that smaller polarons (with higher vibration frequency) arise in thinner flakes. Gray squares represent experimental data, while blue and red spheres are calculated from theory. Panel (E) illustrates small and large polarons. Arrows in magnified inset depict attractive (red) and repulsive (blue) electrical forces.

Molecule’s “fingerprint” may help explain formation of life on earth

Molecule’s “fingerprint” may help explain formation of life on earth

The chemical element sulphur is essential for all life forms and is a building block of proteins and amino acids. By studying sulphur-based molecules in space, scientists are working to understand the chemical processes that might have led to the formation of life on Earth.

German researchers from the Max Planck Institute for Extraterrestrial Physics recently discovered a special type of molecule called singly deuterated methyl mercaptan (CH2DSH). They found it near a young star, similar to our Sun.

Using the Canadian Light Source (CLS) at the University of Saskatchewan (USask), Dr. Hayley Bunn and colleagues were able to create a “fingerprint” of the molecule by analyzing how it shakes and rotates in response to ultrabright synchrotron light. Now, other researchers on the international team are using this fingerprint or signature to look for more of the same molecules in distant space. This could enable them to piece together how the molecules for life formed on Earth, billions of years ago.

“We are really trying to understand how far we can go, chemically, toward larger biological molecules and what environments are needed to form them,” says Bunn. “Ultimately it would be nice to answer one day, how is this then inherited into planets and hopefully life?”

The CLS synchrotron was pivotal to the success of Bunn’s research, since the vibrational signals of this basic molecule are extremely hard to detect. Synchrotron light is vastly brighter than conventional sources, making it possible to identify even the faintest signals.

Read more on CLS website

Researchers proved reversible alloy metallic nanocatalysts: a step forward to clean energies

Researchers proved reversible alloy metallic nanocatalysts: a step forward to clean energies

A team of researchers from several institutions in Spain, Germany, and Argentina, led by the ITQ-UPV-CSIC, has conducted a comprehensive exploration of the exsolution process in double perovskite oxides. The study, published in Journal of Materials Chemistry A, reveals important insights into how temperature controls nanoparticle composition, how these particles change during chemical cycling, and provides the first measurement of the reversibility of ternary alloyed nanoparticles.

Advanced X-ray techniques at the ALBA Synchrotron provided detailed views of both structural and surface changes during the exsolution process. This study is of great interest for the development of reversible electrochemical cells that can work in fuel cell and electrolyzer modes for renewable energy storage and production of green fuels.

Perovskite oxides are versatile materials prized for their tunable properties and diverse chemical characteristics, making them exceptional platforms for catalyst design in multiple clean energy technologies, including fuel cells and the conversion of CO₂ and water into CO and hydrogen. Their unique ability to release and—potentially—reabsorb metal nanoparticles makes these materials particularly valuable for creating stable, high-performance catalysts. Exsolution has emerged as a promising nanocatalyst fabrication route in the last decade. Through exsolution, perovskite oxides can produce well-anchored metal nanoparticles under controlled conditions. If this process can also work in reverse, it could enable catalyst regeneration.

However, little is known about how this release-reabsorb process works. For this reason, researchers at Instituto de Tecnología Química (ITQ-UPV-CSIC), the Helmholtz-Zentrum Berlin für Materialien und Energie GmbH (HZB) from Germany, the ALBA Synchrotron, and other research institutions in Spain and Argentina, used advanced X-ray techniques to observe the process in real-time in a quest to understand the dynamics of ternary alloyed nanoparticles. This study specifically examines how three metals—iron, cobalt, and nickel—combine to form nanoparticles within a complex oxide structure, aiming to understand what controls their formation and reversibility.

The researchers investigated the exsolution of ternary alloyed nanoparticles in a specially designed oxide material using a combination of in situ and ex situ techniques. They discovered that the exsolution temperature significantly influences the composition of the resulting nanoparticles. At lower temperatures, nickel-rich nanoparticles preferentially form due to the faster diffusion of nickel. Increasing the temperature promotes the exsolution of cobalt and iron, leading to a more homogeneous composition. This finding highlights the potential for tuning nanoparticle composition by controlling the exsolution temperature.

The study also explored the reversibility of the exsolution process, demonstrating that some nanoparticles can be reintegrated into the perovskite lattice upon oxidation, while others remain on the surface in an altered state. This reversibility has important implications for catalyst regeneration and stability.

Read more on ALBA website

Image: Schematic representation and field emission scanning electron microscopy micrographs of the ex situ redox processes affecting exsolution, oxidation and re-exolution.

Cutting-edge experiments reveal ‘hidden’ details in transforming material

Cutting-edge experiments reveal ‘hidden’ details in transforming material

Using SLAC’s LCLS for one of the first studies of its kind, researchers discover surprising behaviors of a complex material that could have important implications for designing faster microelectronic devices.

Phase changes are central to the world around us. Probably the most familiar example is when ice melts into water or water boils into steam, but phase changes also underlie heating systems and even digital memory, such as that used in smartphones. 

Triggered by pulses of light or electricity, some materials can switch between two different phases that represent binary code 0s and 1s to store information. Understanding how a material transforms from one state or phase to another is key to tailoring materials with specific properties that could, for instance, increase switching speed or operate at lower energy costs.

Read more on SLAC website

Image: In X-ray photon correlation spectroscopy, X-rays interact with a sample and produce interference patterns, called speckle patterns, that encode information about the structure of the material at the atomic and nanoscale. As a material transforms from one phase to another, the speckle pattern will change. The research team used these patterns to follow the changes in real time as a material transformed from one crystalline phase to another, triggered by a single pulse of light. 

 Credit: Aaron Lindenberg/SLAC National Accelerator Laboratory

Quantum heat dynamics toggled by magnetic fields

Quantum heat dynamics toggled by magnetic fields

Scientists discover unknown mechanism of heat conduction in quantum material

The ability to conduct heat is one of the most fundamental properties of matter, crucial for engineering applications. Scientists know well how conventional materials, such as metals and insulators, conduct heat. However, things are not as straightforward under extreme conditions such as temperatures close to absolute zero combined with strong magnetic fields, where strange quantum effects begin to dominate. This is particularly true in the realm of quantum materials. Researchers from the Helmholtz-Zentrum Dresden-Rossendorf (HZDR), University of Bonn, and Centre national de la recherche scientifique (CNRS) now exposed the semimetal zirconium pentatelluride (ZrTe5) to high magnetic fields and very low temperatures. They found dramatically enhanced heat oscillations caused by a novel mechanism. This finding challenges the widely held belief that magnetic quantum oscillations should not be detectable in the heat transport of semimetals, as the scientists report in the journal PNAS.

The quantum material ZrTe5 belongs to the class of so-called topological semimetals. In physics, the term “topological” describes special materials that, due to their unique electronic structure, have extremely robust (“topologically protected”) conduction properties. In such materials, quantum effects can lead to unconventional and often bizarre phenomena that could play a crucial role in advancing future quantum technologies. Notably, both research and industry are currently investing considerable effort into developing quantum computers, with topological materials emerging as a promising avenue for their realization. Like ZrTe₅: it combines a rare set of non-trivial electronic properties, making it potentially relevant for high-precision electronics applications and magnetic-field sensor technologies.

“When a normal metal such as silver or copper is placed in strong magnetic fields at temperatures close to absolute zero, that is −273.15 °C, its heat conduction is expected to oscillate − a striking example of quantum mechanical dynamics of electrons in metals. This effect arises due to the existence of the so-called Fermi surface, a boundary between occupied and unoccupied energy states of electrons in a metal”, Dr. Stanisław Gałeski, currently assistant professor at Radboud University and visiting scientist at the Dresden High Magnetic Field (HLD) laboratory at HZDR, explains. “On the other hand, in semimetals, there are very few electrons available to transport heat, and as such, heat conduction is widely believed to be dominated by phonons − emergent particles that represent crystal lattice vibrations. As such, quantum oscillations should not be detectable in the transport of heat”, Gałeski sums up more traditional expectations. However, several recent experiments have found giant quantum oscillations in the heat conduction of semimetals, questioning the mechanism of heat transport.

Read more on HZDR website

Image: Artistic visualization of a crystalline rod made of the semimetal ZrTe5. There is a heat gradient from one end to the other. In its center, giant oscillations in its heat conduction are toggled by the magnetic field, which is generated by the electromagnet below.

Credit: B. Schröder/HZDR

Volcano’s explosive eruptions defy predictions

Volcano’s explosive eruptions defy predictions

3D X-ray images can help scientists understand and mitigate hazards of strong volcanic eruptions

More than 800 million people live near an active volcano. Some of these volcanoes still defy existing models, making the exact prediction of their eruptions impossible. This is the case for Colli Albani in Italy which has produced major explosions in the past despite its magma being normally associated with mild effusive eruptions. An international team led by the University of Geneva (UNIGE) and including researchers from DESY and Helmholtz-Zentrum Hereon is shedding light on this mystery using an innovative approach: analysing crystals that retain traces of the last eruption using PETRA III. Published in the Journal of Petrology, this study paves the way for new analytical methods in volcanology and strengthens hazard mitigation.

Monitoring volcanoes to anticipate their potentially devastating effects requires a detailed understanding of the signals that precede an eruption. However, this task becomes challenging when a volcano defies predictive models—such as Colli Albani, located just 20 kilometres from Rome. In theory, its magmatic composition should result in low-intensity eruptions. Yet, its past eruptions tell a different story.

Magma contains volatiles (mainly water and carbon dioxide), like opening the cap of a bottle of soda, when the magma rises toward the surface, it releases the volatiles, and the more viscous the magma, the more difficult it is for the gas to escape. The retention of gas results in a progressive increase of pressure which eventually leads to violent explosive eruptions. In theory, Colli Albani should not pose this risk as its magma is not very viscous. Yet, it has produced several violent and large volume explosive eruptions, the most recent occurring 355,000 years ago, when it spewed up to 30 km³ of scorching ash and molten rock into the atmosphere.

To learn more, the research team analysed ‘‘melt inclusions’’ from the magma of the last eruption with the help of synchrotron radiation. These tiny droplets of magma, measuring just one-hundredth of a millimetre, were sealed inside crystals before the explosion, preserving valuable clues about the magma’s chemistry, its water and carbon dioxide content—key factors in its explosiveness—as well as its temperature and pressure. In total, the researchers studied 35 crystals containing 2,000 inclusions.

An Innovative Approach to Probing Magma

Scientists from UNIGE collaborated with several institutions, including DESY, the University of Rome Tre, the University of Bristol and the Helmholtz-Zentrum Hereon. Using PETRA III, the team was able to obtain high-resolution 3D X-ray images of magma inclusions.

“This approach is innovative in volcanology, particularly in the study of melt inclusions. It opens up new perspectives in the field,” explains Corin Jorgenson, first author of the study and a doctoral student at the Department of Earth Sciences of the UNIGE Faculty of Science at the time of the research, now a postdoctoral researcher at the University of Strathclyde in Scotland.

Read more on DESY website

Image: Photomicrograph of a clinopyroxene crystal. This mineral formed in a magma chamber. Melt Inclusions (in black) are present in these crystals.

Credit: Corin Jorgenson, University of Strathclyde