More than a thousand studies on coronaviruses summarized by researchers at Eötvös Loránd University

Researchers at Eötvös Loránd University (ELTE) have processed the scientific findings on COVID-19 disease severity, which reveal the risk factors and possible causes of the differential course of the disease.

Peer-Reviewed Publication

EÖTVÖS LORÁND UNIVERSITY (ELTE), FACULTY OF SCIENCE

 

IMAGE: RESEARCHERS AT EÖTVÖS LORÁND UNIVERSITY (ELTE) HAVE PROCESSED THE SCIENTIFIC FINDINGS ON COVID-19 DISEASE SEVERITY, WHICH REVEAL THE RISK FACTORS AND POSSIBLE CAUSES OF THE DIFFERENTIAL COURSE OF THE DISEASE. THEIR STUDY WAS PUBLISHED IN VIRUSES. view more 

CREDIT: PHOTO: MÜLLER VIKTOR, ZSICHLA LEVENTE / EÖTVÖS LORÁND UNIVERSITY

Researchers at Eötvös Loránd University (ELTE) have processed the scientific findings on COVID-19 disease severity, which reveal the risk factors and possible causes of the differential course of the disease. Their study was published in Viruses.

The COVID-19 pandemic has affected the whole world, but the number of cases and deaths is very unevenly distributed between geographical regions and individual risk has been significantly influenced by the infected individual, the infectious virus strain and some characteristics of the environment.

The clinical course and outcome of COVID-19 is highly variable.

Understanding why some people become asymptomatic while others lose their lives is essential both to cure the disease and to control the epidemic.

Levente Zsichla, a student of the Institute of Biology at ELTE and his supervisor, Dr. Viktor Müller, Associate Professor at the Institute of Biology at ELTE, analysed more than a thousand studies to provide a comprehensive picture of how processes influence the severity of COVID-19 at the individual level.

In their study, they examined in detail the role of demographic factors (age and biological sex, and related pregnancy), the interactions of the disease with other infectious and non-communicable comorbidities, and the influence of genetic polymorphisms, lifestyle, microbiota and established immune memory. In addition, the impact of genetic variation in the coronavirus (SARS-CoV-2) and environmental factors such as air pollution and socioeconomic status were reviewed.

For each factor, the evidence, sometimes conflicting, for the association with COVID-19 outcomes was examined and possible mechanisms of action were outlined. They also reviewed the complex interactions between different risk factors and the feedback effects of epidemic closures on these factors. We review some examples from their study.

WHAT IS ALREADY KNOWN - AGE AND UNDERLYING DISEASES

Advanced age is among the strongest risk factors for COVID-19 mortality. This effect was first reported in early 2020 and has since been confirmed by numerous studies. These findings show that

the risk of death in adults doubles approximately every 6-7 years of life,

and (in the case of the first major wave of the pandemic) has already exceeded 1% in the 65-75 age group. Ageing of lung tissue and the immune system, and the age-related increase in sterile systemic inflammation levels may also be responsible for this phenomenon.

Some chronic diseases also increase the risk of severe COVID-19, but there are exceptions and controversial cases. While obesity, diabetes, hypertension, chronic kidney disease and cardiovascular disease are certainly risk factors, the results for several immunological, neurological and mental diseases are still inconclusive. There is also such controversy within lung diseases. While chronic obstructive pulmonary disease seems to have a clear aggravating effect, in the majority of studies allergic asthma has been found to be a neutral or even risk-reducing underlying condition. This may be because, although both conditions are associated with shortness of breath, chest tightness, wheezing and coughing, the causes and mechanisms of the two conditions are largely different.

MEN ARE MORE VULNERABLE, WOMEN HAVE MORE COMPLICATIONS

Data show that men are at about twice the risk of serious COVID-19 infection, not only among older people but also regardless of age. Similar associations have also been shown for other viral respiratory diseases (e.g. influenza) and infectious pneumonia, so the mechanism is probably not unique to COVID-19. The role of several X-linked genes and the differential expression of other genes that play a key role in the immune system may underlie this phenomenon. In addition, men with severe COVID-19 often have immunological problems involving a family of immune molecules produced against viruses, interferons. In a significant proportion of patients, the production of these interferons is disturbed or the body starts to produce antibodies against them, inactivating the otherwise protective proteins.

Women have a lower risk of severe COVID-19 disease, but a higher rate of post-COVID-19 syndrome. Pregnancy is a particular risk factor for the course of the infection, with pregnant infected women more likely to develop gestational hypertension, more often being admitted to intensive care and the consequences for the foetus/infant.

INDIRECT EFFECTS OF THE ENVIRONMENT

Poor socioeconomic status, including poverty, poor housing conditions or belonging to an ethnic minority, has been shown to be a risk factor in many countries. It also affects people's lifestyle, nutrition, exposure to air pollution and infectious respiratory diseases, and the availability and quality of health care. Unsurprisingly, and supported by research evidence, regular physical activity and a healthy diet are beneficial for overall health and COVID-19 outcomes, while excessive alcohol consumption increases the risk of serious disease. Even more surprisingly, the impact of smoking, which significantly impairs respiratory function, on the clinical outcome of SARS-CoV-2 infection remains undetermined. In contrast, a growing body of research links long-term exposure to high concentrations of particulate matter with severe coronavirus disease.

SIGNIFICANCE OF THE REVIEW

There have been several summaries of factors influencing the outcome of COVID-19, but these have either covered a small area or provided only a sketchy summary of a wider range of risk factors. The new study provides the most comprehensive overview of risk factors,

highlighting the dominant role of age, biological sex, certain chronic underlying diseases, previously acquired specific immunity, and the infectious virus strain in the course of the disease.

If you take the time to read it - and we recommend it to our brave and persistent readers - you will see how complex the science is and how often it is difficult to draw clear conclusions. It also reveals the amazing scientific collaboration that has taken place over the past few years as the international scientific community has joined forces to find answers and solutions to the pandemic threatening the world. Fortunately, with the development of effective vaccines and the immunity of those who have been affected, the pandemic has gradually been pushed into the background. Nevertheless, as the virus is expected to be with us for a long time to come, the conclusions of this study will be needed well into the future.

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JOURNAL

Viruses

DOI

10.3390/v15010175 

METHOD OF RESEARCH

Meta-analysis

ARTICLE TITLE

Risk Factors of Severe COVID-19: A Review of Host, Viral and Environmental Factors

New antioxidants found in beef, chicken, and pork!

Establishment of a highly sensitive detection method for imidazole dipeptide oxidation derivatives

Peer-Reviewed Publication

OSAKA METROPOLITAN UNIVERSITY

 

IMAGE: OSAKA METROPOLITAN UNIVERSITY RESEARCHERS DEVELOPED A NEW PROTOCOL FOR SELECTIVE AND HIGHLY SENSITIVE DETECTION, DISCOVERING FIVE TYPES OF 2-OXO-IMIDAZOLE-CONTAINING DIPEPTIDES(2-OXO-IDPS) USING MASS SPECTROMETRY. THE 2-OXO-IDPS, PRESENT IN LIVING ORGANISMS, EXHIBIT VERY HIGH ANTIOXIDANT ACTIVITY, AND WERE FOUND TO BE ABUNDANT IN MEAT INCLUDING, BEEF, PORK, AND CHICKEN. view more 

CREDIT: HIDESHI IHARA, OSAKA METROPOLITAN UNIVERSITY

Osaka, Japan – Imidazole dipeptides (IDPs), which are abundant in meat and fish, are substances produced in the bodies of various animals, including humans, and have been reported to be effective in relieving fatigue and preventing dementia. However, the physiological mechanism by which IDPs exhibit these activities had not been determined previously.

A research team, led by Professor Hideshi Ihara from the Osaka Metropolitan University Graduate School of Science, was the first to discover 2-oxo-imidazole-containing dipeptides (2-oxo-IDPs)—which have one more oxygen atom than normal IDPs—and found that they are the most common variety of IDPs derivatives in the body. The researchers also found that they have remarkably high antioxidant activity.

In their study, the researchers established a method for selective and highly sensitive detection of five types of 2-oxo-IDPs using mass spectrometry, which enables quantitative detection of trace 2-oxo-IDPs in living organisms. Using this method, they revealed for the first time that beef, pork, chicken, and other meats contain antioxidants, not only IDPs but a variety of different 2-oxo-IDPs. Their findings were published in Antioxidants.

“We hope that this research method, which enables advanced analysis of 2-oxo-IDPs, will be applied not only to basic biology but also to medicine, agriculture, and pharmacy, where it will help improve peoples’ health and prevent diseases,” concluded Professor Ihara.

###

About OMU 

Osaka Metropolitan University is a new public university established in April 2022, formed by merger between Osaka City University and Osaka Prefecture University. For more research news visit https://www.omu.ac.jp/en/ or follow @OsakaMetUniv_en and #OMUScience.

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JOURNAL

Antioxidants

DOI

10.3390/antiox11122401 

METHOD OF RESEARCH

Experimental study

SUBJECT OF RESEARCH

Animal tissue samples

ARTICLE TITLE

Quantitative Determination of 2-Oxo-Imidazole-Containing Dipeptides by High-Performance Liquid Chromatography/Tandem Mass Spectrometry

ARTICLE PUBLICATION DATE

Avoiding a global chocolate disaster – how tracing and recalls avoided a worldwide Salmonella outbreak

Largest ever recall of chocolate products in global history, just before Easter, prevented thousands of extra cases; a total of 455 cases of Salmonella Typhimurium found in 17 countries; UK had most cases with 128

Reports and Proceedings

EUROPEAN SOCIETY OF CLINICAL MICROBIOLOGY AND INFECTIOUS DISEASES

Like any other manufactured food product, chocolate can be contaminated if key ingredients or processes break down. In a presentation in a pre-ECCMID day for this year’s European Congress of Clinical Microbiology & Infectious Diseases (ECCMID 2023, Copenhagen, 15-19 April), Dr Johanna Takkinen, Principal Expert for Food- and Waterborne Diseases at the European Centres for Disease Control and Prevention (ECDC), Stockholm, Sweden, will discuss the drama as the story unfolded, and the lessons learned from an outbreak of Salmonella Typhimurium in Kinder Chocolate Eggs traced to a Belgian chocolate factory.

”If not for clear and co-ordinated action across Europe and beyond, there may have been many thousands more children falling ill, and potentially many deaths,” says Dr Takkinen.

Authorities in the UK (the UK Health Security Agency [UKHSA]) first raised the alarm in ECDC-hosted alert platform EpiPulse on 17 February 2022, reporting a cluster of 18 children reported ill with monophasic Salmonella Typhimurium infections since January 2022. Of these, seven were hospitalised and five of the seven had bloody diarrhoea, a serious symptom. “Preliminary interviews of first cases indicated Kinder chocolate products as a possible vehicle of infection. Several countries then began reporting an increasing number of infections with strains the same as the UK outbreak,” explains Dr Takkinen. By 18 February, France had reported its first 2 cases, and by 18 March 59 cases were reported in five countries.

Late in March 2022, ECDC coordinated a teleconference with affected countries when four non-human monophasic S. Typhimurium isolates, genetically close to the human isolates, were identified in a public database. Within a week, these isolates were confirmed originating from one particular Belgian chocolate factory. Prior to this, identifying which factory or factories were involved was difficult since there are four factories within the European Union that produce Kinder chocolate in large quantities. This new microbiological evidence allowed the various agencies to focus their investigations on one factory.

Meanwhile, the Food Standards Agency (FSA) in the UK* and the Food Safety Authority (FSA) in Ireland and the UK FSA decided to recall, on April 2**, certain Kinder Chocolate products (including Kinder Surprise Eggs).  On April 8 authorities, now confident the factory was identified, ordered that chocolate factory (Ferrero) closed, and two days later had issued a global recall of products from the factory. The alert reached 130 countries, and in addition to the 401 cases* identified in the EU and UK combined (the UK had the most cases, with 128), further cases were identified in Switzerland (49) and Canada (4) and the USA (1) – giving a global total of 455 cases in 17 countries.  The ECDC and EFSA also published Rapid Outbreak Assessments to keep the public updated.

 

Children under 10 years old made up most of the reported cases (86%), and around two thirds (61%) were female. A number of adults (27), most aged 21-40 and women (18 of the 27), were also infected. Among these adults were a handful of men and women in the age groups 41-70 years. Of 349 analysed cases, 28% were serious enough to be hospitalised, with many experiencing symptoms such as bloody diarrhoea. Of 179 cases interviewed (mostly via family members), 170 (95%) reported eating types of Kinder chocolate products there that were produced in the implicated Belgian factory.

Testing of multiple products from the factory resulted in 81 Salmonella positive samples, with two different strains, in the Belgian factory between 3 December 2021 and 25 January 2022 (most by PCR). The authorities estimated that the original contamination event happened before December 2021; one final product was positively identified as contaminated with Salmonella on 3 December, and  the first case with symptom progression was on 12 December. Due to the time taken to move from production to retail sites, the majority of early cases began to appear in January 2022. The tank for anhydrous milk fat (known as buttermilk) were identified as hot spots for contamination, with the anhydrous milk fat coming from a factory in Italy which tested negative for Salmonella.  The Ferrero factory went through several rounds of cleaning and disinfection before being reallowed to open on 17 June 2022, for three months with conditions, but having its permanent licence for production reissued on 17 September, 2022.

Dr Takkinen says: “Children were at very high risk in this outbreak, with several chocolate products but mostly chocolate eggs affected leading up to Easter. Only through intensive collaboration with multidisciplinary teams of public health experts (microbiologists, epidemiologists) and regular cross-sectoral communication (public health – food safety) were authorities able to prevent a devastating global outbreak.”

She adds: “Also crucial in preventing the escalation of the outbreak was the effective early detection of cases through Salmonella surveillance in the UK, and the early verification of a rapidly evolving multi-country outbreak thanks to prompt responses by countries.”

Dr Johanna Takkinen, Principal Expert for Food- and Waterborne Diseases at the European Centres for Disease Control and Prevention (ECDC), Stockholm, Sweden. Please e-mail to arrange interview. E) johanna.takkinen@ecdc.europa.eu / press@ecdc.europa.eu

Tony Kirby in the ECCMID Media Centre. T) +44 7834 385827 E) tony@tonykirby.com

For link to Dr Takkinen’s slides, click here

*For the ECDC update showing case numbers from different countries, click here

**For the Food Standards Agency (UK) notice on this, original published April 2, 2022, click here

This press release is based on a session in the Pre-ECCMID days taking place on February 15 and 16, online. The main ECCMID congress in 15-18 April in Copenhagen, Denmark.

How a record-breaking copper catalyst converts CO2 into liquid fuels

Researchers at Berkeley Lab have made real-time movies of copper nanoparticles as they evolve to convert carbon dioxide and water into renewable fuels and chemicals. Their new insights could help advance the next generation of solar fuels

Peer-Reviewed Publication

DOE/LAWRENCE BERKELEY NATIONAL LABORATORY

 

IMAGE: ARTIST’S RENDERING OF A COPPER NANOPARTICLE AS IT EVOLVES DURING CO2 ELECTROLYSIS: COPPER NANOPARTICLES (LEFT) COMBINE INTO LARGER METALLIC COPPER “NANOGRAINS” (RIGHT) WITHIN SECONDS OF THE ELECTROCHEMICAL REACTION, REDUCING CO2 INTO NEW MULTICARBON PRODUCTS. view more 

CREDIT: YAO YANG/BERKELEY LAB

Since the 1970s, scientists have known that copper has a special ability to transform carbon dioxide into valuable chemicals and fuels. But for many years, scientists have struggled to understand how this common metal works as an electrocatalyst, a mechanism that uses energy from electrons to chemically transform molecules into different products. 

Now, a research team led by Lawrence Berkeley National Laboratory (Berkeley Lab) has gained new insight by capturing real-time movies of copper nanoparticles (copper particles engineered at the scale of a billionth of a meter) as they convert CO2 and water into renewable fuels and chemicals: ethylene, ethanol, and propanol, among others. The work was reported in the journal Nature last week. 

“This is very exciting. After decades of work, we’re finally able to show – with undeniable proof – how copper electrocatalysts excel in CO2 reduction,” said Peidong Yang, a senior faculty scientist in Berkeley Lab’s Materials Sciences and Chemical Sciences Divisions who led the study. Yang is also a professor of chemistry and materials science and engineering at UC Berkeley. “Knowing how copper is such an excellent electrocatalyst brings us steps closer to turning CO2 into new, renewable solar fuels through artificial photosynthesis.”

The work was made possible by combining a new imaging technique called operando 4D electrochemical liquid-cell STEM (scanning transmission electron microscopy) with a soft X-ray probe to investigate the same sample environment: copper nanoparticles in liquid. First author Yao Yang, a UC Berkeley Miller postdoctoral fellow, conceived the groundbreaking approach under the guidance of Peidong Yang while working toward his Ph.D. in chemistry at Cornell University. 

Scientists who study artificial photosynthesis materials and reactions have wanted to combine the power of an electron probe with X-rays, but the two techniques typically can’t be performed by the same instrument. 

Electron microscopes (such as STEM or TEM) use beams of electrons and excel at characterizing the atomic structure in parts of a material. In recent years, 4D STEM (or “2D raster of 2D diffraction patterns using scanning transmission electron microscopy”) instruments, such as those at Berkeley Lab’s Molecular Foundry, have pushed the boundaries of electron microscopy even further, enabling scientists to map out atomic or molecular regions in a variety of materials, from hard metallic glass to soft, flexible films. 

On the other hand, soft (or lower-energy) X-rays are useful for identifying and tracking chemical reactions in real time in an operando, or real-world, environment. 

But now, scientists can have the best of both worlds. At the heart of the new technique is an electrochemical “liquid cell” sample holder with remarkable versatility. A thousand times thinner than a human hair, the device is compatible with both STEM and X-ray instruments. 

The electrochemical liquid cell’s ultrathin design allows reliable imaging of delicate samples while protecting them from electron beam damage. A special electrode custom-designed by co-author Cheng Wang, a staff scientist at Berkeley Lab’s Advanced Light Source, enabled the team to conduct X-ray experiments with the electrochemical liquid cell. Combining the two allows researchers to comprehensively characterize electrochemical reactions in real time and at the nanoscale. 

Getting granular

During 4D-STEM experiments, Yao Yang and team used the new electrochemical liquid cell to observe copper nanoparticles (ranging in size from 7 nanometers to 18 nanometers) evolve into active nanograins during CO2 electrolysis – a process that uses electricity to drive a reaction on the surface of an electrocatalyst. 

The experiments revealed a surprise: copper nanoparticles combined into larger metallic copper “nanograins” within seconds of the electrochemical reaction. 

To learn more, the team turned to Wang, who pioneered a technique known as “resonant soft X-ray scattering (RSoXS) for soft materials,” at the Advanced Light Source more than 10 years ago. 

With help from Wang, the research team used the same electrochemical liquid cell, but this time during RSoXS experiments, to determine whether copper nanograins facilitate CO2 reduction. Soft X-rays are ideal for studying how copper electrocatalysts evolve during CO2 reduction, Wang explained. By using RSoXS, researchers can monitor multiple reactions between thousands of nanoparticles in real time, and accurately identify chemical reactants and products. 

The RSoXS experiments at the Advanced Light Source – along with additional evidence gathered at Cornell High Energy Synchrotron Source (CHESS) – proved that metallic copper nanograins serve as active sites for CO2 reduction. (Metallic copper, also known as copper(0), is a form of the element copper.) 

During CO2 electrolysis, the copper nanoparticles change their structure during a process called “electrochemical scrambling.” The copper nanoparticles’ surface layer of oxide degrades, creating open sites on the copper surface for CO2 molecules to attach, explained Peidong Yang. And as CO2 “docks” or binds to the copper nanograin surface, electrons are then transferred to CO2, causing a reaction that simultaneously produces ethylene, ethanol, and propanol along with other multicarbon products. 

“The copper nanograins essentially turn into little chemical manufacturing factories,” Yao Yang said.

Further experiments at the Molecular Foundry, the Advanced Light Source, and CHESS revealed that size matters. All of the 7-nanometer copper nanoparticles participated in CO2 reduction, whereas the larger nanoparticles did not. In addition, the team learned that only metallic copper can efficiently reduce CO2 into multicarbon products. The findings have implications for “rationally designing efficient CO2 electrocatalysts,” Peidong Yang said.

The new study also validated Peidong Yang’s findings from 2017: That the 7-nanometer-sized copper nanoparticles require low inputs of energy to start CO2 reduction. As an electrocatalyst, the 7-nanometer copper nanoparticles required a record-low driving force that is about 300 millivolts less than typical bulk copper electrocatalysts. The best-performing catalysts that produce multicarbon products from CO2 typically operate at high driving force of 1 volt.

The copper nanograins could potentially boost the energy efficiency and productivity of some catalysts designed for artificial photosynthesis, a field of research that aims to produce solar fuels from sunlight, water, and CO2. Currently, researchers within the Department of Energy-funded Liquid Sunlight Alliance (LiSA) plan to use the copper nanograin catalysts in the design of future solar fuel devices. 

“The technique’s ability to record real-time movies of a chemical process opens up exciting opportunities to study many other electrochemical energy conversion processes. It’s a huge breakthrough, and it would not have been possible without Yao and his pioneering work,” Peidong Yang said. 

Researchers from Berkeley Lab, UC Berkeley, and Cornell University contributed to the work. Other authors on the paper include co-first authors Sheena Louisa and Sunmoon Yu, former UC Berkeley Ph.D. students in Peidong Yang’s group, along with Jianbo Jin, Inwhan Roh, Chubai Chen, Maria V. Fonseca Guzman, Julian Feijóo, Peng-Cheng Chen, Hongsen Wang, Christopher Pollock, Xin Huang, Yu-Tsuan Shao, Cheng Wang, David A. Muller, and Héctor D. Abruña.

Parts of the experiments were performed by Yao Yang at Cornell under the supervision of Héctor Abruña, professor of chemistry and chemical biology, and David A. Muller, professor of engineering. 

This work was supported by the DOE Office of Science. 

The Molecular Foundry and Advanced Light Source are user facilities at Berkeley Lab. 

(From left to right): Julian Feijoo, Jianbo Jin, Cheng Wang, Peidong Yang, Yao Yang, Inwhan Roh, and Maria Fonseca Guzman at the Advanced Light Source.

Yao Yang (center) loads a sample into the soft X-ray scattering chamber as Cheng Wang (left) and Peidong Yang (right) observe at the RSoXS Beamline (Beamline 11.0.1.2) at the Advanced Light Source.

CREDIT

Thor Swift/Berkeley Lab

Movie for evolution of Cu NPs. [VIDEO] | EurekAlert! Science News Releases

Video of a 4D-STEM experiment during which Yao Yang and team used the new electrochemical liquid cell to observe copper nanoparticles (ranging in size from 7 nanometers to 18 nanometers) evolve into active nanograins during CO2 electrolysis – a process that uses electricity to drive a reaction on the surface of an electrocatalyst. The new electrochemical liquid cell allows researchers to resolve images of objects smaller than 10 nanometers.

CREDIT

Yao Yang/Berkeley Lab. Courtesy of Nature.

Founded in 1931 on the belief that the biggest scientific challenges are best addressed by teams, Lawrence Berkeley National Laboratory and its scientists have been recognized with 16 Nobel Prizes. Today, Berkeley Lab researchers develop sustainable energy and environmental solutions, create useful new materials, advance the frontiers of computing, and probe the mysteries of life, matter, and the universe. Scientists from around the world rely on the Lab’s facilities for their own discovery science. Berkeley Lab is a multiprogram national laboratory, managed by the University of California for the U.S. Department of Energy’s Office of Science.

DOE’s Office of Science is the single largest supporter of basic research in the physical sciences in the United States, and is working to address some of the most pressing challenges of our time. For more information, please visit energy.gov/science.

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JOURNAL

Nature

DOI

10.1038/s41586-022-05540-0 

METHOD OF RESEARCH

Imaging analysis

SUBJECT OF RESEARCH

Not applicable

ARTICLE TITLE

Operando studies reveal active Cu nanograins for CO2 electroreduction

New superalloy could cut carbon emissions from power plants

Researchers repurpose 3D printing to discover high-performance material

Peer-Reviewed Publication

DOE/SANDIA NATIONAL LABORATORIES

 

IMAGE: SANDIA NATIONAL LABORATORIES TECHNOLOGIST LEVI VAN BASTIAN WORKS TO PRINT MATERIAL ON THE LASER ENGINEERED NET SHAPING MACHINE, WHICH ALLOWS SCIENTISTS TO 3D PRINT NEW SUPERALLOYS. view more 

CREDIT: CRAIG FRITZ, SANDIA NATIONAL LABORATORIES

ALBUQUERQUE, N.M. — As the world looks for ways to cut greenhouse gas emissions, researchers from Sandia National Laboratories have shown that a new 3D-printed superalloy could help power plants generate more electricity while producing less carbon.

Sandia scientists, collaborating with researchers at Ames National Laboratory, Iowa State University and Bruker Corp., used a 3D printer to create a high-performance metal alloy, or superalloy, with an unusual composition that makes it stronger and lighter than state-of-the-art materials currently used in gas turbine machinery. The findings could have broad impacts across the energy sector as well as the aerospace and automotive industries, and hints at a new class of similar alloys waiting to be discovered.

“We’re showing that this material can access previously unobtainable combinations of high strength, low weight and high-temperature resiliency,” Sandia scientist Andrew Kustas said. “We think part of the reason we achieved this is because of the additive manufacturing approach.”

The team published their findings in the journal Applied Materials Today.

Material withstands high heat, essential for power plant turbines

About 80% of electricity in the U.S. comes from fossil fuel or nuclear power plants, according to the U.S. Energy Information Administration. Both types of facilities rely on heat to turn turbines that generate electricity. Power plant efficiency is limited by how hot metal turbine parts can get. If turbines can operate at higher temperatures, “then more energy can be converted to electricity while reducing the amount of waste heat released to the environment,” said Sal Rodriguez, a Sandia nuclear engineer who did not participate in the research.

Sandia’s experiments showed that the new superalloy — 42% aluminum, 25% titanium, 13% niobium, 8% zirconium, 8% molybdenum and 4% tantalum — was stronger at 800 degrees Celsius (1,472 degrees Fahrenheit) than many other high-performance alloys, including those currently used in turbine parts, and still stronger when it was brought back down to room temperature.

“This is therefore a win-win for more economical energy and for the environment,” Rodriguez said.

Energy is not the only industry that could benefit from the findings. Aerospace researchers seek out lightweight materials that stay strong in high heat. Additionally, Ames Lab scientist Nic Argibay said Ames and Sandia are partnering with industry to explore how alloys like this could be used in the automotive industry.

“Electronic structure theory led by Ames Lab was able to provide an understanding of the atomic origins of these useful properties, and we are now in the process of optimizing this new class of alloys to address manufacturing and scalability challenges,” Argibay said.

The Department of Energy and Sandia’s Laboratory Directed Research and Development program funded the research.

Discovery highlights changes in materials science

Additive manufacturing, also called 3D printing, is known as a versatile and energy-efficient manufacturing method. A common printing technique uses a high-power laser to flash-melt a material, usually a plastic or a metal. The printer then deposits that material in layers, building an object as the molten material rapidly cools and solidifies.

But this new research demonstrates how the technology also can be repurposed as a fast, efficient way to craft new materials. Sandia team members used a 3D printer to quickly melt together powdered metals and then immediately print a sample of it.

Sandia’s creation also represents a fundamental shift in alloy development because no single metal makes up more than half the material. By comparison, steel is about 98% iron combined with carbon, among other elements.

“Iron and a pinch of carbon changed the world,” Kustas said. “We have a lot of examples of where we have combined two or three elements to make a useful engineering alloy. Now, we’re starting to go into four or five or beyond within a single material. And that’s when it really starts to get interesting and challenging from materials science and metallurgical perspectives.”

Scalability, cost are challenges to overcome

Moving forward, the team is interested in exploring whether advanced computer modeling techniques could help researchers discover more members of what could be a new class of high-performance, additive manufacturing-forward superalloys.

“These are extremely complex mixtures,” said Sandia scientist Michael Chandross, an expert in atomic-scale computer modeling who was not directly involved in the study. “All these metals interact at the microscopic — even the atomic — level, and it’s those interactions that really determine how strong a metal is, how malleable it is, what its melting point will be and so forth. Our model takes a lot of the guesswork out of metallurgy because it can calculate all that and enable us to predict the performance of a new material before we fabricate it.”

Kustas said there are challenges ahead. For one, it could be difficult to produce the new superalloy in large volumes without microscopic cracks, which is a general challenge in additive manufacturing. He also said the materials that go into the alloy are expensive. So, the alloy might not be appropriate in consumer goods for which keeping cost down is a primary concern.

“With all those caveats, if this is scalable and we can make a bulk part out of this, it’s a game changer,” Kustas said.

Sandia National Laboratories is a multimission laboratory operated by National Technology and Engineering Solutions of Sandia LLC, a wholly owned subsidiary of Honeywell International Inc., for the U.S. Department of Energy’s National Nuclear Security Administration. Sandia Labs has major research and development responsibilities in nuclear deterrence, global security, defense, energy technologies and economic competitiveness, with main facilities in Albuquerque, New Mexico, and Livermore, California.

Sandia National Laboratories technologist Levi Van Bastian fills a hopper with raw material to print on the Laser Engineered Net Shaping machine. What appears to be a liquid is powdered metal.

3D-printing technologies like Laser Engineered Net Shaping, shown here, are helping scientists at Sandia National Laboratories rapidly discover, prototype and test new materials.

CREDIT

Craig Fritz, Sandia National Laboratories

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JOURNAL

Applied Materials Today

DOI

10.1016/j.apmt.2022.101669 

ARTICLE TITLE

Applied Materials Today 29 (2022) 101669 Available online 17 November 2022 2352-9407/© 2022 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).Extreme hardness at high temperature with a lightweight additively manufactured multi-principal element superalloy

High intensity fires do not reverse bush encroachment in an African savanna

Despite an initial short-term effect, high-intensity fires did not result in a meaningful reversal in bush encroachment in the long-term

Peer-Reviewed Publication

STELLENBOSCH UNIVERSITY

 

IMAGE: A TYPICAL FIRE IN SOUTH AFRICA'S KRUGER NATIONAL PARK SHOWING HOW BOTH THE GRASSES AND SHRUBS BURN. view more 

CREDIT: BRIAN VAN WILGEN

A decade-long experiment on the use of high-intensity fire to control bush encroachment in South Africa’s Kruger National Park (KNP) has revealed that, despite an initial short-term effect, these fires did not result in a meaningful reversal in bush encroachment in the long-term.

The results of this long-term and large-scale experiment were published in the Journal of Applied Ecology today (16 February 2023), in an article titled “High-intensity fires may have limited medium-term effectiveness for reversing woody plant encroachment in an African savanna”.

Prof. Brian van Wilgen, emeritus professor in invasion biology at Stellenbosch University (SU) and one of the co-authors, says most papers that advocate the use of high-intensity fires are based on observation over a short time: “I think this is the first study to assess this management practice’s effectiveness over a decade,” he adds.

Decade-long experiment

Bush or woody encroachment, which is a process where the density of smaller trees and shrubs are increasing, is taking place across the world. This is worrying because increased woody cover results in less grass available for animals that eat grass or use it as habitat. Although the causes are complex and not that clear, a decrease in the use of fire, coupled with an increase in CO2, may be to blame in savannas.

In 2010 and again in 2013, adjacent sites in the southern parts of the KNP, covering thousands of hectares, were burned using low, medium and high intensity fires. The objective was to examine whether high-intensity fires can be used to reverse bush encroachment. At the time of the first burn application, KNP officials had to deal with substantial negative publicity after some animals were mortally injured.

A study reporting the effects on woody plant cover one year after the completion of the second set of experimental fires showed that woody plant cover did indeed decline significantly over this short period. The initial study, however, cautioned that the long-term efficacy of these high intensity fires still needed to be confirmed.

In 2020, using a combination of ground surveys and remote sensing data, scientists from South African National Parks (SANParks), Harvard University and the Centre for Invasion Biology at Stellenbosch University compared the 2010 data with their 2020 observations. Despite the initial encouraging results, they found that the reduced woody plant cover was not maintained after ten years. Even though there were large differences between the fire treatment sites one year after the experimental fires, these differences had disappeared after 10 years, strongly suggesting that differences in fire intensity did not have a long-term effect on bush encroachment.

Even more concerning was the trend of tall tree loss in the KNP. Over the past decade, trees taller than ten metres declined by about 65% across all the experimental sites, regardless of the fire treatment.

According to SANParks scientist and first author on the article, Tercia Strydom, this was because of a combination of elephant and fire damage: “Tall trees are normally capable of withstanding frequent savanna fires due to their thick bark. But when elephants debark a tree (because they eat it), that thick protective bark is removed, exposing the inner wood. When this inner wood dries out, it burns and smoulders within the tree until the tree eventually succumbs,” she explains.

Lessons learned

According to Prof. van Wilgen, the paper shows the value of long-term monitoring to establish the real outcome, and not to jump to conclusions: “It also shows how complex things can be, and that there is no easy fix to bush encroachment”.

Dr Izak Smit, senior scientist at SANParks and another co-author, says the park continues to follow a strategic adaptive management approach in which local context is paramount: “Best available knowledge needs to be gathered from the literature, and based on that a careful evaluation must inform what management action you consider appropriate to implement in your area of interest. The outcomes of this action should be carefully monitored to see whether or not you actually obtain the anticipated outcomes”.

“This way, ecology reveals its complexity and nuance in different contexts and allows us to fine-tune the way we manage protected areas – learning as we continue to manage in the face of uncertainty,” he adds.

They warn that, on a global scale, inter-continental and even intra-continental generalisations regarding the most appropriate management actions for bush encroachment remain elusive. According to Strydom, this case study may not even be representative of other parts of southern Africa based on differences in elephant density, soil type and rainfall, amongst a plethora of other factors.

The way forward

KNP has a long history of scientific research and looking forward, Dr Smit says they are now exploring the potential of early wet or early dry season fires to address bush encroachment as an alternative to high-intensity fires.

He explains: “When woody species are dormant during the dry season, they move a lot of their resources to their roots while the top parts are ‘resting’. If a fire consumes the above-ground parts during this period, the plant still has a lot of resources stored below-ground from which it can resprout when conditions become favourable. However, if the plant is in leaf and a fire burns the above-ground parts, it is expected that the damage is more costly to the plant, which is what we want when concerned about bush encroachment. The trick is therefore to try to burn when there is sufficient dry grass to carry fires of reasonable intensity, while at the same time the bush species are in a more vulnerable leaf-on phase. Spring sometimes provides this window of opportunity where grass is still dry enough to burn and the woody species are already in leaf and thus more vulnerable to fire damage”.

In the end, he says, one needs to understand both the local (e.g., fire, grazing) and global drivers of change (such as elevated atmospheric CO2), and their interactions with each other, in order to tease out if and how different management actions (or inactions) may improve the situation, or even make it worse.

Vegetation in the Kruger National Park showing separate layers – scattered tall trees that are declining in number due to the actions of fire and elephants, and an understory of low shrubs that is becoming more dense”.

CREDIT

Brian van Wilgen

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JOURNAL

Journal of Applied Ecology

DOI

10.1111/1365-2664.14362 

METHOD OF RESEARCH

Observational study

SUBJECT OF RESEARCH

Not applicable

ARTICLE TITLE

High-intensity fires may have limited medium-term effectiveness for reversing woody plant encroachment in an African savanna

ARTICLE PUBLICATION DATE

16-Feb-2023

COI STATEMENT

Izak Smit is an Associate Editor of the Journal of Applied Ecology, but took no part in the peer review and decision-making processes for this paper. The authors have no other conflicts of interest to declare.