PETRA III (DESY) – Lightsources.org

Examining written artefacts with x-rays

2023/04/272023/05/26

DESY and the Cluster of Excellence ‘Understanding Written Artefacts’ are jointly breaking new ground in the material analysis of historical written artefacts

Within a new cooperation between the Cluster of Excellence ‘Understanding Written Artefacts’ (UWA) at Universität Hamburg and the German Electron Synchrotron DESY, scientists from Hamburg are now investigating historical written artefacts at the X-ray radiation source PETRA III. The prominent advantage of X-ray investigations is that the artefacts can be examined without any destruction. As far as the examination method allows, no special sample preparation is required – the precious and unique objects thus remain intact.

Currently, there are two pilot studies underway. The first study deals with Mesopotamian cuneiform tablets. These millennia-old artefacts are an essential source for understanding this ancient, advanced civilization. However, many tablets that cannot be dated and originated are of limited value for research. DESY and UWA are investigating 36 objects from the Museum für Kunst und Gewerbe (MKG) and the Hamburg State and University Library (SUB) collections to understand the context of the origin of a tablet by analyzing the nature of the clay. The powder diffraction method was chosen for the non-destructive and basic material characterization of this investigation. In this method, all mineral grains are detected by the X-ray beam in a local area, and these thus contribute to a characteristic diffraction pattern for a specific part of the clay tablet. The diffraction pattern consists of individual diffraction reflections for each contained mineral and gives atomic-level information about the crystalline structure. With suitable software, the mineral components can be analyzed, and thus an insight into the atomic structure – as well as the quantitative composition – of these minerals can be obtained.

Image: A tsakali during the experiment

Credit: DESY, Marta mayer

Engineered wall paint could kill corona viruses

2023/03/082023/03/17

Investigation of aerosols on titanium dioxide shows promising routes to surface and air disinfection

Common wall paint could potentially be modified to kill the Corona virus and many other pathogens. This is an important finding of a study from a research team including DESY scientists on the virus-killing effect of titanium dioxide (TiO₂), a ubiquitous white pigment that is found in paints, plastic products and sunscreens. TiO₂ also has many other important applications relevant to environmental sustainability and renewable energy. The international team led by Heshmat Noei from the DESY NanoLab reports its results in the journal Applied Materials & Interfaces published by the American Chemical Society (ACS).

“Titanium dioxide is widely used as a pigment to whiten a wide range of products,” explains Noei. “But it is also a powerful catalyst in many applications such as air and water purification and self-cleaning materials. Therefore, we saw it as a promising candidate for a virus inactivating coating.” Teaming up with the group of virologist Ulrike Protzer and Greg Ebert from the research centre Helmholtz Munich and the Technische Universität München, the scientists tested titanium dioxide´s power against the corona virus. “We were the first to apply corona viruses on a titanium dioxide surface and investigate what happens,” says Noei.

Hard X-ray photoelectron spectroscopy at the PETRA III beamline P22 at DESY provides the necessary high chemical and elemental sensitivity to resolve subtle chemical changes. The research team investigated the contact process on the surface and was able to clarify that the amino acids of the corona virus spike protein attach to the titanium dioxide surface, trapping the virus and preventing it from binding to human cells. “We found that the virus adsorbs to the titanium dioxide surface and cannot detach again and will eventually be inactivated by dehydration and be denatured,” explains the paper´s main author Mona Kohantorabi from the DESY NanoLab. “Moreover, the titanium dioxide catalyses the inactivation of the virus by light. For our study we used ultraviolet light, which triggered the inactivation of the virus within 30 minutes, but we believe the catalyst can be further optimised to accelerate the inactivation and, more importantly, work under standard indoor lighting. We believe it could then be used as an antiviral coating for walls, windows and other surfaces for instance in hospitals, schools, airports, elderly homes and kindergardens.”

Image: An image taken with an atomic force microscope from the investigation: The SARS-CoV-2 particles (light) adsorb on the titanium dioxide surface. There, structural proteins are inactivated by denaturation and oxidation by light irradiation.

Credit: DESY Nanolab, Mona Kohantorabi

Asteroid impact in slow motion

2023/02/072023/02/09

High-pressure study solves 60-year-old mystery

For the first time, researchers have recorded live and in atomic detail what happens to the material in an asteroid impact. The team of Falko Langenhorst from the University of Jena and Hanns-Peter Liermann from DESY simulated an asteroid impact with the mineral quartz in the lab and pursued it in slow motion in a diamond anvil cell, while monitoring it with DESY’s X-ray source PETRA III. The observation reveals an intermediate state in quartz that solves a decades-old mystery about the formation of characteristic lamellae in quartz hit by an asteroid. Quartz is ubiquitous on the Earth’s surface, and is, for example, the major constituent of sand. The analysis helps to better understand traces of past impacts, and may also have significance for entirely different materials. The researchers present their findings in the journal Nature Communications.

Large asteroid impacts can melt significant amounts of material from Earth’s crust (artist’s impression). Credit: NASA, Don Davis

Asteroid impacts are catastrophic events that create huge craters and sometimes melt parts of Earth’s bedrock.“ Nevertheless, craters are often difficult to detect on Earth, because erosion, weathering and plate tectonics cause them to disappear over millions of years,” Langenhorst explains. Therefore, minerals that undergo characteristic changes due to the force of the impact often serve as evidence of an impact. For example, quartz sand (which chemically is silicon dioxide, SiO₂) is gradually transformed into glass by such an impact, with the quartz grains then being crisscrossed by microscopic lamellae. This structure can only be explored in detail under an electron microscope. It can be seen in material from the relatively recent and prominent Barringer crater in Arizona, USA, for example.

Image: Large asteroid impacts can melt significant amounts of material from Earth’s crust (artist’s impression)

Credit: NASA, Don Davis

Unusual compound found in Rembrandt’s The Night Watch

2023/01/172023/01/18

An international team of scientists from the Rijksmuseum, the CNRS, the ESRF the European Synchrotron, the University of Amsterdam and the University of Antwerp, have discovered a rare lead compound (named lead formate) in Rembrandt’s masterpiece The Night Watch. This discovery, which is a first in the history of the scientific study of paintings, provides new insight into 17th-century painting technique and the conservation history of the masterpiece. The study is published in Angewandte Chemie – International edition.

The Night Watch, painted in 1642 and displayed today in the Rijksmuseum Amsterdam (The Netherlands), is one of Rembrandt’s most important masterpieces and largest work of art. In the framework of the 2019 Operation Night Watch, the largest research and conservation project ever undertaken for Rembrandt’s masterpiece, an international research team joined forces to study how the painting materials react chemically and with time.

The team of scientists combined multi-scale imaging methods in order to chemically study the materials used by Rembrandt in The Night Watch. A X-ray scanning instrument developed at the University of Antwerp (Belgium) was applied directly to the painting, while tiny fragments taken from the painting were studied with synchrotron micro X-ray probes, at the ESRF, the European Synchrotron (France), and PETRA-III facility (Germany). These two types of analyses revealed the presence of an unexpected organo-metallic compound: lead formates. This compound had never been detected before in historic paintings: “In paintings, lead formates have only been reported once in 2020, but in model paintings (mock-up, fresh paints). And there lies the surprise: not only do we discover lead formates, but we identify them in areas where there is no lead pigment, white, yellow. We think that probably they disappear fast, this is why they were not detected in old master paintings until now”, explains Victor Gonzalez, CNRS researcher at the Supramolecular and Macromolecular Photophysics and Photochemistry (PPSM) laboratory (CNRS/ENS Paris-Saclay) and first author of the paper.

Image: The Night Watch, Rembrandt van Rijn, 1642

Credit: Rijskmuseum Amsterdam

Cellulose-based actuators can be programmed and repair themselves

2022/11/212022/11/22

Smart gifts will soon unwrap themselves

With the help of the high-brilliance X-ray source PETRA III, a German-Swedish research group has developed a new cellulose polymer material that can be specifically animated to move by moisture, making it an ideal base material for programmable actuators. In addition, the composite material is also very resistant to stretching and able to repair itself, as the group reports in the scientific journal “Advanced Functional Materials”. The mechanism of this self-healing in particular was investigated at PETRA III.

n nature, fascinating functions and mechanisms have prevailed over millions of years of evolution. In bionics research, scientists try to copy and reproduce these efficient methods from nature. For example, in sensors or bionic actuators, active elements that – controlled by a signal – can switch or move something. Modern actuators should be programmably stimulable, very robust and able to cope with a wide range of working conditions.

The research team with members from the Royal Institute of Technology Stockholm (KTH), DESY and the Helmholtz Centre for Heavy Ion Research has now produced a thin film of cellulose nanofibres with two types of polymers, following the example of biological tissue. To do this, they mixed polyvinyl alcohol (PVA) and polystyrene sulfonate (PSS) with the cellulose fibrils and poured the solution onto a glass plate. When it dried out, a circular film was formed in which a tight network of chemical and physical bonds formed. “It is the polystyrene sulphonate in particular that makes the film extremely stretchable and tough,” says DESY scientist Qing Chen, first author of the study. “This ingredient of the solution can be broadened by mixing food colouring agents, thus making it more colourful and diverse.”

Pieces up to several centimetres in size can be cut out of this film, which bend when exposed to moisture. “In principle, we can make an active wrapping paper out of the material,” says Stephan Roth (DESY and KTH), head of the PETRA III beamline P03 and co-author of the study, “you just have to spray some moisture on it, and it unwraps itself.”

Image: The cellulose polymer actuators can be used for a variety of purposes.

Credit: DESY, Qing Chen

New ant genus named after DESY

2022/09/012022/09/08

Researchers spot previously unknown extinct ant in 20 million-years-old amber

An international team of scientists led by Friedrich Schiller University Jena has identified a previously unknown extinct ant in a unique piece of African amber about 20 million years old. The team used DESY’s X-ray light source PETRA III to examine the critical fossil remains from 13 individual animals at a specialised measuring station operated by Helmholtz-Zentrum Hereon and realised that these could not be attributed to any known species. The new species even establishes a completely new genus of primordial ants, as the scientists from the Universities of Jena, Rennes (France) and Gdansk (Poland) as well as from Hereon report in the scientific journal Insects. The new genus was named after DESY, the new species after Hereon: With the scientific name †Desyopone hereon gen. et sp. nov., the discoverers honour the two research institutions, which had contributed significantly to this discovery with modern imaging methods.

“It is a great honour that DESY is the namesake of the new primordial ant genus,“ emphasises Christian Schroer, Leading Scientist of PETRA III at DESY. “And we are delighted that we can provide the brilliant X-ray light for such top-class research with our facility.” PETRA III is a particle accelerator that sends fast electrons on slalom paths, where they emit highly focused X-ray light that can be used to study the finest details of a wide variety of samples.

Natural substances show promise against coronavirus

2022/08/182022/08/18

X-ray screening identifies compounds blocking a major corona enzyme

Three natural compounds present in foods like green tea, olive oil and red wine are promising candidates for the development of drugs against the coronavirus. In a comprehensive screening of a large library of natural substances at DESY’s X-ray source PETRA III the compounds bound to a central enzyme vital for the replication of the coronavirus. All three compounds are already used as active substances in existing drugs, as the team headed by Christian Betzel from the University of Hamburg and Alke Meents from DESY reports in the journal Communications Biology. However, if and when a corona drug can be developed on the basis of these compounds remains to be investigated.

“We tested 500 substances from the Karachi Library of Natural Compounds if they bind to the papain-like protease of the novel coronavirus, which is one of the main targets for an antiviral drug,” explains the study’s main author Vasundara Srinivasan from the University of Hamburg. “A compound that binds to the enzyme at the right place can stop it from working.”

The papain-like protease (PL^pro) is a vital enzyme for virus replication: When a cell is hijacked by the coronavirus, it is forced to produce building blocks for new virus particles. These proteins are manufactured as a long string. PL^pro then acts like a molecular pair of scissors, cutting the proteins from the string. If this process is blocked, the proteins cannot assemble new virus particles.

Image: The paper’s main author Vasundara Srinivasan at an X-ray set-up to test protein crystals in the lab.

Credit: University of Hamburg, Susanna Gevorgyan

Aleksei Kotlov’s #My1stLight

2022/07/292022/07/29

Aleksei was responsible for setting up the new P66 beamline at PETRA III at DESY

Setting up the P66 beamline was a challenging time. The years of discussions, iterations, doubts, calculations, ordering of parts, and construction end at some point with commissioning of the beamline. Only then could you see the final result of your work and see that all decisions were right. To me personally it was like the birth of a baby. Suddenly you realize, that small beam spot on the sample is a big event for you and whole beamline community and to make it happen you have invested a significant part of your life.

Image: Aleksei on the P66 beamline at PETRA III

Efficient production technique for a novel ‘green’ fertiliser

2022/05/112022/05/11

Advanced milling technique produces slow-release soil nutrient crystals

A purely mechanical method can produce a novel, more sustainable fertiliser in a less polluting way. That is the result of a method optimised at DESY’s light source PETRA III. An international team used PETRA III to optimise the production method that is an adaptation of an ancient technique: by milling two common ingredients, urea and gypsum, the scientists produce a new solid compound that slowly releases two chemical elements critical to soil fertilisation, nitrogen, and calcium. The milling method is rapid, efficient, and clean—as is the fertiliser product, which has the potential to reduce the nitrogen pollution that fouls water systems and contributes to climate change. The scientists also found that their process is scalable; therefore, it could be potentially implemented industrially. The results by scientists from DESY; the Ruđer Bošković Institute (IRB) in Zagreb, Croatia; and Lehigh University in the USA have been published in the journal Green Chemistry. The new fertiliser still needs to be tested in the field.

For several years, scientists from DESY and IRB, have been collaborating to explore the fundamentals of mechanical methods for initiating chemical reactions. This method of processing, called mechanochemistry, uses various mechanical inputs, such as compressing, vibrating, or, in this case, milling, to achieve the chemical transformation. “Mechanochemistry is quite an old technique,” says Martin Etter, beamline scientist at the P02.1 beamline at PETRA III. “For thousands of years, we’ve been milling things, for example, grain for bread. It’s only now that we’re starting to look at these mechanochemical processes more intensively using X-rays and seeing how we can use those processes to initiate chemical reactions.”

Etter’s beamline is one of the few in the world where mechanochemistry can be routinely performed and analysed using X-rays from a synchrotron. Etter has spent years developing the beamline and working with users to fine-tune methods for analysing and optimising mechanochemical reactions. The result has been a globally renowned experiment setup that has been used in studying many types of reactions important to materials science, industrial catalysis, and green chemistry.

Image: The co-crystals of the novel fertiliser (symbolised here with gypsum) release their nutrients much more slowly

Credit: DESY, Gesine Born

Brilliant people support light source experiments

2022/02/212022/02/21

Academic and industrial researchers have access to world class experimental techniques at light sources around the world. Experimental time on the beamlines is extremely precious and in order to get the most out of this ‘beamtime’ scientists need expert advice and support. Today’s #LightSourceSelfie Monday Montage is a tribute to the brilliant scientists, engineers, computer scientists and other support staff who work at light sources and provide external researchers with the assistance they need to ensure their experiments are successful and they come away with useful data that will advance their scientific studies.

Monday Montage – Brilliant people support light source experiments

Light sources have demonstrated huge adaptability during the pandemic

2022/01/132022/01/13

Johanna Hakanpää is the beamline scientist for P11, one of the macromolecular crystallography beamlines at PETRAIII at DESY in Hamburg. Originally from Finland, she studied chemistry and then did her masters and PhD work in protein crystallography. Johanna was drawn to the field because she wanted to understand how life really works. Supporting health related research is important to her and Johanna is especially inspired by her son who is a patient of celiac disease. Together they hope that one day, with the help of science, he will be able to eat normally without having to think about what is contained in his food. Johanna started her light source journey as a user and was really impressed by the staff scientists who supported her during her experiments. This led her to apply for a beamline scientist position and she successfully made the transition, learning the technical aspects of the beamlines on the job.

In her #LightSourceSelfie, Johanna highlights the adaptability of light sources during the pandemic as a key strength. Being part of a team that was able to keep the lights on for users via remote experiments is a reflection of the commitment that Johanna and her colleagues have when it comes to facilitating science. Thousands of staff at light sources all around the world have shown the same commitment, ensuring scientific advances can continue. This is particularly true for vital research on the SARS-CoV-2 virus itself. Learn more about this research here: https://lightsources.org/lightsource-research-and-sars-cov-2/

Quantum Physics in Proteins

2021/11/042021/11/16

Artificial intelligence affords unprecedented insights into how biomolecules work

A new analytical technique is able to provide hitherto unattainable insights into the extremely rapid dynamics of biomolecules. The team of developers, led by Abbas Ourmazd from the University of Wisconsin–Milwaukee and Robin Santra from DESY, is presenting its clever combination of quantum physics and molecular biology in the scientific journal Nature. The scientists used the technique to track the way in which the photoactive yellow protein (PYP) undergoes changes in its structure in less than a trillionth of a second after being excited by light.

“In order to precisely understand biochemical processes in nature, such as photosynthesis in certain bacteria, it is important to know the detailed sequence of events,” Santra explains their underlying motivation. “When light strikes photoactive proteins, their spatial structure is altered, and this structural change determines what role a protein takes on in nature.” Until now, however, it has been almost impossible to track the exact sequence in which structural changes occur. Only the initial and final states of a molecule before and after a reaction can be determined and interpreted in theoretical terms. “But we don’t know exactly how the energy and shape changes in between the two,” says Santra. “It’s like seeing that someone has folded their hands, but you can’t see them interlacing their fingers to do so.”

X-ray insights may enable better plastics production

2021/09/172021/09/22

Analysis helps to understand fragmentation of catalyst particles in ethylene polymerisation

An X-ray study at DESY is pointing the way towards a better understanding of plastics production. A team led by Utrecht University investigated so-called Ziegler-type catalysts, the workhorses in the world’s polyethylene and polypropylene production, at DESY’s X-ray source PETRA III. As the scientists report in the journal JACS Au, the catalyst microparticles fragment into an astonishing variety of smaller particles during polymer production. The results allow for a better finetuning of desired polymer properties and may even help to further increase polymer yield.

Polyolefins, such as polyethylene (PE) and polypropylene (PP), play an important role in everyday life. Applications range from food packaging to increase the lifetime of the product to the sterile packing of medical equipment to the insulation of electrical cables. To prepare tailored polyolefins on demand, a versatile class of catalyst materials, such as the Ziegler-type catalysts, are used that consist of very small particles containing various metals such as titanium.

The catalyst particles have typical sizes of only a few tens of micrometres (thousandths of a millimetre), that is, less than the thickness of a human hair. Thanks to these catalysts, polyethylene can be produced at ambient pressure and temperature and with enhanced material characteristics. “Polyolefin research today focusses on specifically tailoring polymer properties to the demands of customers, and this is where insights about the polymerisation process such as the ones obtained in this study are crucial,” explains Koen Bossers from Utrecht University, first author of the study.

Image: 434 particles were imaged simultaneously with a resolution of 74 nm and identified and characterised individually with respect to their geometrical properties and fragmentation behaviour. The displayed rendering shows a virtual cut through the tomographic data set where each identified particle is color-coded for better visualisation. Most particles are about 5-6 microns in diameter. The data has further been segmented into regions of similar electron density to separate polymer from catalyst fragments within each particle; these regions are displayed in blue, green, orange, and red and visualised via the virtual cut though the 3-D representation of the catalyst particles. This segmentation allowed for a detailed analysis of the fragmentation behaviour of each particle

Credit: Utrecht University, Roozbeh Valadian

Astonishing diversity: Semiconductor nanoparticles form numerous structures

2021/08/052021/08/19

X-ray study reveals how lead sulphide particles self-organise in real time

The structure adopted by lead sulphide nanoparticles changes surprisingly often as they assemble to form ordered superlattices. This is revealed by an experimental study at PETRA III. A team led by the DESY scientists Irina Lokteva and Felix Lehmkühler, from the Coherent X-ray Scattering group headed by Gerhard Grübel, has observed the self-organisation of these semiconductor nanoparticles in real time. The results have been published in the journal Chemistry of Materials. The study helps to better understand the self-assembly of nanoparticles, which can lead to significantly different structures.

Among other things, lead sulphide nanoparticles are used in photovoltaic cells, light-emitting diodes and other electronic devices. In the study, the team investigated the way in which the particles self-organise to form a highly ordered film. They did so by placing a drop of liquid (25 millionths of a litre) containing the nanoparticles inside a small cell and allowing the solvent to evaporate slowly over the course of two hours. The scientists then used an X-ray beam at the P10 beamline to observe in real time what structure the particles formed during the assembly.

To their surprise, the structure adopted by the particles changed several times during the process. “First we see the nanoparticles forming a hexagonal symmetry, which leads to a nanoparticle solid having a hexagonal lattice structure,” Lokteva reports. “But then the superlattice suddenly changes, and displays a cubic symmetry. As it continues to dry, the structure makes two more transitions, becoming a superlattice with tetragonal symmetry and finally one with a different cubic symmetry.” This sequence has been never revealed before in such detail.

Image: The lead sulphide nanoparticles, which are about eight nanometres (millionths of a millimetre) in size, initially arrange themselves into a layer with hexagonal symmetry

Credit: (Credit: University of Hamburg, Stefan Werner)

X-ray unveils the creation process of materials on several length scales

2021/07/212021/07/28

Nanostructuring often makes materials very powerful in many applications. Some nanomaterials take on the desired complex structures independently during their creation process. Scientists from the University of Hamburg, DESY, ESRF and the Ludwig Maximilians University in Munich have studied the formation of cobalt oxide crystals just a few nanometers in size and how they assemble, while they are still being formed. The results are published in Nature Communications.

Nanomaterials have special properties that make them more effective than conventional materials in various applications. In sensors and catalysts (in green energy production, such as water splitting into energy-rich hydrogen and oxygen) the important chemical processes happen at the surface. Nanostructured materials, even in small amounts, provide a very large surface and are therefore suitable for this kind of applications.

Further potential arises due to the variety of shapes and material combinations that are conceivable on the nanoscale. However, establishing the exact shape of these nanostructures can be a tedious process. Researchers focus on nanocrystals that independently form complex structures without any external influence, for example by sticking together (assembling). This increases their effectiveness in important technological applications, such as green energy generation or sensor technology.

“Often nanoparticles arrange themselves independently, as if following a blueprint, and take on new shapes,” explains Lukas Grote, one of the main authors of the study and scientist at DESY and the University of Hamburg. “Now, however, we want to understand why they are doing this and what steps they go through on the way to their final form. That is why we follow the formation of nanomaterials in real time using high-intensity X-rays. ” For some of the experiments, the researchers used the European Synchrotron Radiation Facility (ESRF) and DESY’s synchrotron radiation source PETRA III.

Image: X-rays from a synchrotron radiation source are both attenuated (absorbed) and deflected (scattered) by matter. Depending on which of these interactions is measured with a certain X-ray technology, conclusions can be drawn about different stages of the development process of a nanomaterial. If you combine both X-ray absorption and X-ray scattering, you can decipher all the steps from the starting material (left) to the fully assembled nanostructures (right).

Credit: Nature Communications

Promising candidates identified for COVID drugs

2021/04/022021/04/06

A team of researchers has identified several candidates for drugs against the coronavirus SARS-CoV-2 at DESY´s high-brilliance X-ray lightsource PETRA III. They bind to an important protein of the virus and could thus be the basis for a drug against Covid-19.

In a so-called X-ray screening, the researchers, under the leadership of DESY, tested almost 6000 known active substances that already exist for the treatment of other diseases in a short amount of time. After measuring about 7000 samples, the team was able to identify a total of 37 substances that bind to the main protease (M^pro) of the SARS-CoV-2 virus, as the scientists report online today in the journal Science. Seven of these substances inhibit the activity of the protein and thus slow down the multiplication of the virus. Two of them do this so promisingly that they are currently under further investigation in preclinical studies. This drug screening – probably the largest of its kind – also revealed a new binding site on the main protease of the virus to which drugs can couple.

Image: In the control hutch of the PETRA III beamline P11, DESY researcher Wiebke Ewert shows on a so-called electron density map where a drug candidate (green) binds to the main protease of the corona virus (blue).

Credit: DESY, Christian Schmid