It’s possible that I shall make an ass of myself. But in that case one can always get out of it with a little dialectic. I have, of course, so worded my proposition as to be right either way (K.Marx, Letter to F.Engels on the Indian Mutiny)
Monday, March 25, 2024
Industrial societies losing healthy gut microbes
Fiber is good for us, but a new study finds that humans are losing the microbes that turn fiber into food for a healthy digestive tract
HEINRICH-HEINE UNIVERSITY DUESSELDORF
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CLOSTRIDIUM CLARIFLAVUM, A FIBER DEGRADING BACTERIUM AT WORK BREAKING DOWN CELLULOSE FIBERS WITH THE HELP OF CELLULOSOMES. PHOTO: ITZHAK MIZRAHI
CREDIT: ITZHAK MIZRAHI, BEN-GURION UNIVERSITY (BGU)
Everyone knows that fiber is healthy and an important part of our daily diet. But what is fiber and why is it healthy? Fiber is cellulose, the stringy stuff that plants are made of. Leaves, stems, roots, stalks and tree-trunks (wood) are made of cellulose. The purest form of cellulose is the long, white fibers of cotton. Dietary fiber comes from vegetables or whole grain products. Why is fiber healthy? Fiber helps to keep our intestinal flora (scientists call it our gut microbiome) happy and balanced. Fiber serves as the starting point of a natural food chain. It begins with bacteria that can digest cellulose, providing the rest of our microbiome with a balanced diet. But our eating habits in industrialized societies are far removed from those of ancient humans. This is impacting our intestinal flora, it seems, as newly discovered cellulose degrading bacteria are being lost from the human gut microbiome, especially in industrial societies, according to a new report in Science. The study comes from the team of Prof. Itzhak Mizrahi at Ben-Gurion University (BGU) of the Negev in Israel, with support from the Weizmann Institute of Science in Rehovot and international collaborators in the US and Europe.
“Throughout human evolution, fiber has always been a mainstay of the human diet,” explains lead investigator Sarah Moraïs from BGU, “It is also a main component in the diet of our primate ancestors. Fiber keeps our intestinal flora healthy.” Moraïs and team identified important new members of the human gut microbiome, cellulose-degrading bacteria named Ruminococcus. These bacteria degrade cellulose by producing large and highly specialized extracellular protein complexes called cellulosomes. “It’s no easy task to degrade cellulose, few bacteria can do it.” explains Ed Bayer, from the Weizmann Institute, a world-leader on cellulosomes and coauthor of the study. “Cellulose is difficult to digest because it is insoluble. Fiber in the gut is like a tree-trunk in a swimming pool, it gets wet but it does not dissolve.”
Cellulosomes are engineered by bacteria to attach to cellulose fibers and peel them apart, like the individual threads in a piece of rope. The cellulosomal enzymes then break down the individual threads of fiber into shorter chains, which become soluble. They can be digested, not only by Ruminococcus, but also by many other members of the gut microbiome. “Bottom line, cellulosomes turn fiber into sugars that feed an entire community, a formidable engineering feat,” says Bayer. The production of cellulosomes puts Ruminococcus at the top of the fiber-degradation cascade that feeds a healthy gut microbiome. But the evolutionary history of Ruminococcus is complicated, and Western culture is taking its toll on our microbiome, as the new study shows.
“These cellulosome-producing bacteria have been around for a long time, their ancestors are important members of the rumen microbiome in cows and sheep,” explains Prof. Mizrahi from BGU, senior author of the study. The rumen is the special stomach organ of cows, sheep and deer, where the grass they eat (fiber) is converted into useful food by cellulose-degrading microbes, including Ruminococcus. “We were surprised to see that the cellulosome-producing bacteria of humans seem to have switched hosts during evolution, because the strains from humans are more closely related to the strains from livestock than to the strains from our own primate ancestors.” That is, it looks like humans have acquired important components of a healthy gut microbiome from livestock that they domesticated early in human evolution. “It’s a real possibility” says Mizrahi, an expert on rumen biology.
But the story does not end there. Sampling of human cohorts revealed that Ruminococcus strains are indeed robust components of the human gut microbiome among human hunter-gatherer societies and among rural human societies, but that they are sparse or missing in human samples from industrialized societies. “Our ancestors in Africa 200,000 years ago did not pick up lunch from a drive-through, or phone in a home-delivery for dinner,” says William Martin at the Heinrich Heine University Düsseldorf in Germany, evolutionary biologist and coauthor of the study. In Western societies this does, however, happen on a fairly large scale. Diet is changing in industrialized societies, far removed from the farms where food is produced. This shift away from a fiber-rich diet is a possible explanation for the loss of important cellulose-degrading microbes in our microbiome, the authors conclude.
How can you counteract this evolutionary decline? It might help doing what doctors and dieticians have been saying for decades: Eat more fiber!
Cryptic diversity of cellulose-degrading gut bacteria in industrialized humans
ARTICLE PUBLICATION DATE
18-Mar-2024
Study finds that for each 10% increase of certain bacteria type in the gut microbiome, the risk of hospitalisation for infections falls by up to a quarter
EUROPEAN SOCIETY OF CLINICAL MICROBIOLOGY AND INFECTIOUS DISEASES
A study of two large European patient cohorts has found that for every 10% increase in butyrate-producing bacteria in a patient’s gut, the risk of hospitalisation for any infection falls by between 14 and 25% across two large national cohorts. The study will be presented at this year’s European Congress of Clinical Microbiology and Infectious Diseases (ECCMID 2024) in Barcelona, Spain (27-30 April) and is by Robert Kullberg, Amsterdam University Medical Center, The Netherlands, and colleagues.
Microbiota alterations are common in patients hospitalised for severe infections and preclinical models have shown that anaerobic butyrate-producing gut bacteria protect against systemic infections. These bacteria were investigated because they are commonly depleted in patients hospitalised for severe infections. Second, butyrate may have protective effects in several intestinal diseases (other than infections).
However, the relationship between microbiota disruptions and increased susceptibility to severe infections in humans remains unclear. In this study, the authors investigated the relationship between baseline gut microbiota and the risk of future infection-related hospitalisation in two large population-based cohorts - from the Netherlands (derivation; HELIUS) and Finland (validation; FINRISK 2002).
Gut microbiota were characterised by sequencing the DNA of bacteria to identify the different types of bacteria present in faecal samples of the participants. The authors measured microbiota composition, diversity, and relative abundance of butyrate-producing bacteria. The primary outcome was hospitalisation or mortality due to any infectious disease during 5–7-year follow-up after faecal sample collection, based on national registry data. The authors then examined associations between microbiota and infection-risk using computer modelling. Further statistical modelling was used to adjust for variables including demographics, lifestyle, antibiotic exposure, and comorbidities.
The researchers profiled gut microbiota from 10699 participants (4248 from The Netherlands and 6451 from Finland. A total of 602 participants (The Netherlands: n=152; Finland: n=450) were hospitalised or died due to infections (mainly community-acquired pneumonia) during follow-up.
Gut microbiota composition of these hospitalised/deceased participants differed from those without hospitalisation for infections. Specifically, each 10% higher abundance of butyrate-producing bacteria was associated with a reduced risk of hospitalisation for infections – 25% lower for participants from the Dutch cohort and 14% lower for the Finnish cohort. All types of infections were assessed together, not any one in particular. These associations remained unchanged following adjustment for demographics, lifestyle, antibiotic exposure, and comorbidities.
The authors say: “Gut microbiome composition, specifically colonisation with butyrate-producing bacteria, is associated with protection against hospitalisation for infectious diseases in the general population across two independent European cohorts. Further studies should investigate whether modulation of the microbiome can reduce the risk of severe infections.”
The authors say further analysis will be needed before trails in patients can begin. One of the challenges is the face are the butyrate-producing bacteria are strictly anaerobic (meaning they respire without using oxygen and cannot tolerate oxygen), which makes it very difficult to transport viable bacteria into the gut. Several research groups are working on addressing these challenges.
This press release is based onabstract CS0502 at the European Congress of Clinical Microbiology and Infectious Diseases (ECCMID). The material has been peer reviewed by the congress selection committee. It is about to be submitted to a medical journal for publication. The full paper is not yet available but the authors are happy to answer your questions.
Deciphering the role of bitter and astringent polyphenols in promoting well-being
Scientists determine how dietary polyphenols influence health through gut sensory receptors
SHIBAURA INSTITUTE OF TECHNOLOGY
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DIETARY UPTAKE OF POLYPHENOLS ALTERS THE GUT MICROFLORA AND STIMULATES THE SECRETION OF SPECIFIC HORMONES THAT INDUCE CROSS-TALK WITH THE BRAIN VIA THE SENSORY NERVES. THE ASTRINGENT AND BITTER PROPERTIES OF POLYPHENOLS ARE RESPONSIBLE FOR THEIR PROTECTIVE EFFECT AGAINST CARDIOVASCULAR, METABOLIC, AND NEURODEGENERATIVE DISORDERS.
Polyphenols are powerful plant metabolites known for their antioxidant properties, offering potential health benefits and protection against various diseases. With over 8,000 identified varieties, these substances are found in plentiful amounts in various fruits, vegetables, tea, and coffee. Besides adding color and flavor to foods, polyphenols play a crucial role in promoting health and overall well-being. Despite their bitter and astringent taste, recent studies indicate that they may hold the key to a range of health benefits, including the prevention of cardiovascular diseases, neurodegenerative conditions, and age-related sensory decline. However, there are significant gaps in understanding how exactly they exert these beneficial effects, particularly in terms of their interactions with the body.
To fill this knowledge gap, Professor Naomi Osakabe along with Dr. Yasuyuki Fujii from Shibaura Institute of Technology, and Professor Vittorio Calabrese from the University of Catania, Italy explored the interaction between polyphenols and human health, and its consequent impact. The findings of their study were published in Volume 14, Issue 2 of Biomolecules on 17th February, 2024.
Sharing the inspiration behind their work Prof. Osakabe remarks, “Although many researchers have conducted polyphenol research for more than 30 years, a major challenge has been to elucidate the mechanisms behind their beneficial health effects.” This review attempts to understand the ways in which polyphenols interact with sensory receptors in the gastrointestinal tract, ultimately influencing metabolic pathways and promoting overall well-being.
Epidemiological evidences have long established the protective effects of polyphenols against various chronic conditions such as cardiovascular diseases, metabolic disorders, neurodegenerative diseases, and age-related degeneration of sensory organs. The major challenge in decoding the underlying mechanism of action is their unavailability in blood and/or organs. Polyphenols are usually broken down in the lower gut by intestinal bacteria and excreted in feces. Recent studies have reported that ingested dietary polyphenols can alter the composition of the gut microflora, altering the composition of secondary metabolites in the colon. It is hypothesized that these altered metabolites may be absorbed and affect the metabolic and cognitive functions. However, the type and amount of polyphenol varies greatly with diet and individuals making it quite difficult to establish a causal correlation.
Sensory receptors are specialized cells located close to nerve endings and are widely distributed in specialized organs such as eyes, ears, and even the gut. In recent years, sensory nutrition, a new field of study examining the cross-talk between ingested food or beverages, the brain, and its impact on human behavior, has garnered significant attention. Some reports have suggested that food signals contribute to homeostasis via gut-based sensory receptors.
Delving deeper to unearth the association between polyphenols and the gut, researchers in this study revealed that polyphenols, which are inherently bitter in taste, interact with the bitter taste receptor, the taste receptor 2 (T2R) receptors. Furthermore, some studies found that until polyphenols are excreted, they stay in contact with I-, K-, and L- cells of the intestine expressing T2Rs, or with gastrointestinal sensory nerves and epithelial cells that express TRP channels for an extended time. Astringency of polyphenols was suggested to be a somatosensory perception (a sensation which can occur anywhere in the body) and was correlated with improved blood pressure and risk factors for heart diseases. Polyphenols caused a marked increase in blood flow-dependent vasorelaxation (FMD) levels at moderate doses, known as the hormetic effect. Researchers have found that astringent polyphenols interact with transient receptor potential (TRP) channels. However, further investigation is needed to clearly understand this interaction. These findings strongly suggested that polyphenols exert their beneficial effects via sensory receptors of the gastrointestinal tract.
The astringent and bitter properties of polyphenols offer various therapeutic properties. An experimental animal study demonstrated that repeated intake of stringent polyphenols reduced FMD response significantly along with blood pressure. Another study reported that consumption of bitter polyphenols increased gastrointestinal hormone secretion, thereby regulating blood glucose levels and glucose tolerance. Astringent polyphenols have been observed to regulate the hypothalamic-pituitary-adrenal (HPA) axis activation, thereby improving mood and memory function. Bitter and astringent perception of polyphenols have also been attributed for their anti-obesity effects.
The integration of polyphenol-rich ingredients in functional beverages and snacks, could therefore revolutionize the way we approach nutrition and disease prevention. Elaborating on the long-term impact of their work, a hopeful Prof. Osakabe explains, “Our study is the first to identify that sensory stimuli in food can promote homeostasis and paves the way for the development of novel food products aimed at promoting human health.”
Overall, by comprehensively looking at the underlying mechanisms responsible for the beneficial effects of polyphenols, this review represents a significant step forward in our understanding of the health effects of polyphenols and could pave the way towards innovative dietary interventions for well-being.
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Reference
Title of original paper: Share Sensory Nutrition and Bitterness and Astringency of Polyphenols
About Shibaura Institute of Technology (SIT), Japan
Shibaura Institute of Technology (SIT) is a private university with campuses in Tokyo and Saitama. Since the establishment of its predecessor, Tokyo Higher School of Industry and Commerce, in 1927, it has maintained “learning through practice” as its philosophy in the education of engineers. SIT was the only private science and engineering university selected for the Top Global University Project sponsored by the Ministry of Education, Culture, Sports, Science and Technology and will receive support from the ministry for 10 years starting from the 2014 academic year. Its motto, “Nurturing engineers who learn from society and contribute to society,” reflects its mission of fostering scientists and engineers who can contribute to the sustainable growth of the world by exposing their over 8,000 students to culturally diverse environments, where they learn to cope, collaborate, and relate with fellow students from around the world.
Dr. Naomi Osakabe is a distinguished academician and a Professor in the Department of Bio-science and Engineering, Shibaura Institute of Technology, Japan. With over 5,600 publications and extensive experience spanning several years, she is a prominent figure in the field of food functionality. Professor Osakabe's expertise lies in the study of polyphenols, particularly their functionality and health benefits. Notably, she is a director of the Japanese Polyphenol Society, a councilor of the Japanese Oxidative Stress Society, and the Japanese Society of Food Immunology and a consultant of the Japanese Society of Nutrition and Food Science. She has contributed significantly to the advancement of knowledge in areas related to oxidative stress, food immunology, and nutrition science.
Funding Information
This work was supported by JSPS KAKENHI Grant Number JP 23H02166.
THE ENTANGLED PHOTON SOURCE, AN INDIUM-BASED QUANTUM DOT EMBEDDED IN A SEMICONDUCTOR NANOWIRE (LEFT), AND A VISUALIZATION OF HOW THE ENTANGLED PHOTONS ARE EFFICIENTLY EXTRACTED FROM THE NANOWIRE.
Researchers at the University of Waterloo's Institute for Quantum Computing (IQC) have brought together two Nobel prize-winning research concepts to advance the field of quantum communication.
Scientists can now efficiently produce nearly perfect entangled photon pairs from quantum dot sources.
Entangled photons are particles of light that remain connected, even across large distances, and the 2022 Nobel Prize in Physics recognized experiments on this topic. Combining entanglement with quantum dots, a technology recognized with the Nobel Prize in Chemistry in 2023, the IQC research team aimed to optimize the process for creating entangled photons, which have a wide variety of applications, including secure communications.
"The combination of a high degree of entanglement and high efficiency is needed for exciting applications such as quantum key distribution or quantum repeaters, which are envisioned to extend the distance of secure quantum communication to a global scale or link remote quantum computers," said Dr. Michael Reimer, professor at IQC and Waterloo's Department of Electrical and Computer Engineering. "Previous experiments only measured either near-perfect entanglement or high efficiency, but we're the first to achieve both requirements with a quantum dot."
By embedding semiconductor quantum dots into a nanowire, the researchers created a source that creates near-perfect entangled photons 65 times more efficiently than previous work. This new source, developed in collaboration with the National Research Council of Canada in Ottawa, can be excited with lasers to generate entangled pairs on command. The researchers then used high-resolution single photon detectors provided by Single Quantum in The Netherlands to boost the degree of entanglement.
"Historically, quantum dot systems were plagued with a problem called fine structure splitting, which causes an entangled state to oscillate over time. This meant that measurements taken with a slow detection system would prevent the entanglement from being measured," said Matteo Pennacchietti, a PhD student at IQC and Waterloo's Department of Electrical and Computer Engineering. "We overcame this by combining our quantum dots with a very fast and precise detection system. We can basically take a timestamp of what the entangled state looks like at each point during the oscillations, and that's where we have the perfect entanglement."
To showcase future communications applications, Reimer and Pennacchietti worked with Dr. Norbert Lütkenhaus and Dr. Thomas Jennewein, both IQC faculty members and professors in Waterloo's Department of Physics and Astronomy, and their teams. Using their new quantum dot entanglement source, the researchers simulated a secure communications method known as quantum key distribution, proving that the quantum dot source holds significant promise in the future of secure quantum communications.
HELMHOLTZ-ZENTRUM BERLIN FÜR MATERIALIEN UND ENERGIE
The travelling salesman problem is considered a prime example of a combinatorial optimisation problem. Now a Berlin team led by theoretical physicist Prof. Dr. Jens Eisert of Freie Universität Berlin and HZB has shown that a certain class of such problems can actually be solved better and much faster with quantum computers than with conventional methods.
Quantum computers use so-called qubits, which are not either zero or one as in conventional logic circuits, but can take on any value in between. These qubits are realised by highly cooled atoms, ions or superconducting circuits, and it is still physically very complex to build a quantum computer with many qubits. However, mathematical methods can already be used to explore what fault-tolerant quantum computers could achieve in the future. "There are a lot of myths about it, and sometimes a certain amount of hot air and hype. But we have approached the issue rigorously, using mathematical methods, and delivered solid results on the subject. Above all, we have clarified in what sense there can be any advantages at all," says Prof. Dr. Jens Eisert, who heads a joint research group at Freie Universität Berlin and Helmholtz-Zentrum Berlin.
The well-known problem of the travelling salesman serves as a prime example: A traveller has to visit a number of cities and then return to his home town. Which is the shortest route? Although this problem is easy to understand, it becomes increasingly complex as the number of cities increases and computation time explodes. The travelling salesman problem stands for a group of optimisation problems that are of enormous economic importance, whether they involve railway networks, logistics or resource optimisation. Good enough solutions can be found using approximation methods.
The team led by Jens Eisert and his colleague Jean-Pierre Seifert has now used purely analytical methods to evaluate how a quantum computer with qubits could solve this class of problems. A classic thought experiment with pen and paper and a lot of expertise. "We simply assume, regardless of the physical realisation, that there are enough qubits and look at the possibilities of performing computing operations with them," explains Vincent Ulitzsch, a PhD student at the Technical University of Berlin. In doing so, they unveiled similarities to a well-known problem in cryptography, i.e. the encryption of data. "We realised that we could use the Shor algorithm to solve a subclass of these optimisation problems," says Ulitzsch. This means that the computing time no longer "explodes" with the number of cities (exponential, 2N), but only increases polynomially, i.e. with Nx, where x is a constant. The solution obtained in this way is also qualitatively much better than the approximate solution using the conventional algorithm.
"We have shown that for a specific but very important and practically relevant class of combinatorial optimisation problems, quantum computers have a fundamental advantage over classical computers for certain instances of the problem," says Eisert.
In a new review published in the KeAi journal Resources Chemicals and Materials, a team of researchers from China examined the potential of biomass-derived carbon materials for high-performance rechargeable battery electrodes.
A key information that stood out was the authors' emphasis on the hydrothermal method as an approach for synthesizing biomass-derived carbon materials. "In our assessment, we posit that the hydrothermal method stands out as the most promising approach for crafting biomass-derived carbon materials. This technique not only offers a high degree of control but also demonstrates remarkable efficacy in tailoring the microstructure of these materials,” says Qiankun Zhou.
This underscores the importance of precise microstructure control in optimizing the performance of these carbon materials, and the hydrothermal method appears to offer a unique advantage in this regard.
Another interesting aspect of the review is a summary of incorporating other elements into the biomass carbon structures to achieve synergistic effects. The authors suggest that this strategic amalgamation can lead to superior performance in ion batteries.
"Achieving optimal performance often necessitates the incorporation of other elements into biomass carbon structures. This strategic amalgamation leads to a synergistic interaction between the various components, culminating in superior performance in ion batteries,” adds Zhou.
Throughout the review, the authors maintain a balanced perspective, acknowledging the challenges faced by biomass carbon materials, such as limited efficiency, modest yields, and complex fabrication processes. However, they firmly believe that these materials align with the trajectory of future development and possess extensive potential for applications beyond energy storage.
Overall, this review offers a comprehensive and insightful exploration of the use of biomass-derived carbon materials in high-performance rechargeable battery electrodes. It highlights the promising avenues for optimization through microstructure control and strategic incorporation of other elements, while recognizing the growing concerns surrounding the environmental impact of traditional metal-based electrode materials and the need for more sustainable alternatives.
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Contact the author: Wei Yang, School of Energy, Materials and Chemical Engineering, Hefei University, 99 Jinxiu Avenue, Hefei, Anhui, 230601, P. R. China. yangwei@hfuu.edu.cn
The publisher KeAi was established by Elsevier and China Science Publishing & Media Ltd to unfold quality research globally. In 2013, our focus shifted to open access publishing. We now proudly publish more than 100 world-class, open access, English language journals, spanning all scientific disciplines. Many of these are titles we publish in partnership with prestigious societies and academic institutions, such as the National Natural Science Foundation of China (NSFC).
Biomass carbon materials for high-performance secondary battery electrodes: A Review
COI STATEMENT
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper
Reservoir evaluation using petrophysics informed machine learning: A case study
Domain knowledge drives data-driven artificial intelligence in well logging
KEAI COMMUNICATIONS CO., LTD.
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PETROPHYSICAL INFORMED RESIDUAL NEURAL NETWORK FOR MULTI-TASK RESERVOIR PARAMETER PREDICTION WITH THE DATA-MECHANISM-DRIVEN LOSS FUNCTION
Data-driven artificial intelligence, such as deep learning and reinforcement learning, possess powerful data analysis capabilities. These techniques enable the statistical and probabilistic analysis of data, facilitating the mapping of relationships between inputs and outputs without reliance on predetermined physical assumptions. Central to the process of training data-driven models is the utilization of a loss function, which computes the disparity between the model's output and the desired target results (labels). The optimizer then adjusts the model's parameters based on the loss function to minimize the difference between the output and labels.
Meanwhile, geophysical logging involves a wealth of domain knowledge, mathematical models, and physical models. The reliance solely on data-driven models may sometimes yield outcomes that contradict established knowledge. Additionally, training data with uneven distribution and subjective labels can also impact the performance of data-driven models.
A recent study published in the KeAi journal Artificial Intelligence in Geoscience reported the implementation of constraints on the training of data-driven machine learning models using logging response functions in well logging reservoir parameter prediction task.
"Our model, called Petrophysics Informed Neural Network (PINN), integrates petrophysics constraints into the loss function to guide training,” shares the study’s first author Rongbo Shao, a PhD candidate from China University of Petroleum-Beijing. “During model training, if the model output differs from petrophysics knowledge, the loss function is penalized by petrophysics constraints. This brings the output closer to the theoretical value and reduces the impact of labeling errors on model training.”
Additionally, this approach helps in discerning the correct relationships from training data, particularly when dealing with small sample sizes.
“We introduce allowable error and petrophysical constraint weights to make the influence of mechanism models in the machine learning model more flexible,” Shao elaborates. "We evaluated the PINN model's ability to predict reservoir parameters using measured data.”
Shao and his colleagues found that the model has improved accuracy and robustness compared to pure data-driven models. Nonetheless, the researchers noted that selecting petrophysical constraint weights and allowable error remains subjective, hence requiring further exploration.
Corresponding author Prof Lizhi Xiao of China University of Petroleum underscores the significance of this research, "Integrating data-driven AI models with knowledge-driven mechanism models is a promising research area. The success of the PINN model in well logging is a significant step forward for geoscience in this direction."
Xiao emphasizes the need for continued refinement, "The selection of petrophysical constraint weights and allowable error, as well as the adaptability of domain knowledge to varying geological strata, present ongoing challenges. Additionally, the quality of datasets is crucial for the application of AI in geophysical logging. Comprehensive, publicly available well logging datasets with high quality and quantity are needed."
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Contact the author: Rongbo Shao, College of Artificial Intelligence, China University of Petroleum-Beijing, Beijing, China, rongbo_shao@cup.edu.cn
The publisher KeAi was established by Elsevier and China Science Publishing & Media Ltd to unfold quality research globally. In 2013, our focus shifted to open access publishing. We now proudly publish more than 100 world-class, open access, English language journals, spanning all scientific disciplines. Many of these are titles we publish in partnership with prestigious societies and academic institutions, such as the National Natural Science Foundation of China (NSFC).
NEW ORLEANS, March 18, 2024 — Buildings and production of the materials used in their construction emit a lot of carbon dioxide (CO2), a potent greenhouse gas that contributes to global warming and climate change. But storing CO2 in building materials could help make them more environmentally friendly. Scientists report that they have designed a composite decking material that stores more CO2 than is required to manufacture it, providing a “carbon-negative” option that meets building codes and is less expensive than standard composite decking.
The researchers will present their results today at the spring meeting of the American Chemical Society (ACS). ACS Spring 2024 is a hybrid meeting being held virtually and in person March 17-21; it features nearly 12,000 presentations on a range of science topics.
Apart from a few types of cement, carbon-negative composites are scarce, according to David Heldebrant, an organic chemist who is one of the project’s principal investigators. The composite decking his team has developed “is one of the first composite materials to be demonstrably CO2 negative over its life cycle,” he says.
The materials and processes that go into constructing buildings account for 11% of all energy-related carbon emissions, according to the World Green Building Council. Significant efforts have gone into developing building supplies that can offset these emissions, such as using recycled or plant-derived products. However, in many cases, these sustainable alternatives are more expensive than traditional materials or can’t match their properties, such as strength or durability.
One type of construction material — decking — is a multibillion-dollar industry. Decking boards made from a wood plastic composite are a popular alternative to lumber boards because they are less prone to damage from ultraviolet radiation and can last longer. Composite decking is typically made from a blend of wood chips or sawdust and plastic, such as high-density polyethylene (HDPE). To make these composites more sustainable, one alternative is to use fillers that are waste products or would otherwise be burned.
That’s an approach Heldebrant’s colleague Keerti Kappagantula was taking: using low-quality brown coal and lignin, a wood-derived product left over from papermaking, as the filler in decking composites. To make the pulverized coal and lignin particles mix with and stick to plastics, the research team needed to add ester functional groups to the particles’ surfaces. Heldebrant, who works at Pacific Northwest National Laboratory (PNNL) and develops specialized liquids to capture CO2, found out about this work while chatting over coffee with Kappagantula.
Satish Nune, another project investigator, and Heldebrant were excited when they heard about this. “Esters are essentially carboxylic acids, which are a captured form of CO2,” Heldebrant explains. So, the team wanted to do the same thing and put CO2 onto the surface of the particles in the composite to make the material even more environmentally friendly while improving the composites’ mechanical performance.
To test the feasibility of this approach, the team turned to a classic chemical reaction to form a new chemical bond between CO2 and a functional group called a phenol, which is abundant in wood products like coal and lignin. After undergoing the reaction, the lignin and coal particles contained 2–5% CO2 by weight.
The team then mixed varying ratios of these particles with HDPE to form brownish-black composites, and they tested the resulting properties. A composite containing 80% filler maximized the amount of CO2 content while demonstrating strength and durability that meet international building codes for decking materials. It was manufactured via friction extrusion using PNNL’s shear assisted processing and extrusion (ShAPETM) machine. The researchers used this material to form 10-foot-long composites that look and feel similar to any standard wood composites found in decking or lawn furniture.
In addition to their favorable physical properties, the new composite boards offer a substantial price and sustainability advantage. They are 18% cheaper than standard decking composite boards. They also store more CO2 than is released during their manufacture and lifetime, Heldebrant says. If the 3.55 billion feet of decking sold in the U.S. every year were replaced with the researchers’ CO2-negative composite decking, he says, 250,000 tons of CO2 could be sequestered annually, which is equivalent to the yearly emissions from 54,000 cars.
Next, the researchers plan to make additional composite formulations and test the properties. They envision that carbon-negative composites could be developed for a range of building materials, such as fencing and siding. In the meantime, the team is working to commercialize its decking boards. This new carbon-negative decking could be available at building supply retailers as soon as next summer.
The research was funded by the United States Department of Energy Office of Fossil Energy and Carbon Management (FWP 78606) and the Southern California Gas Company (SoCalGas).
Visit the ACS Spring 2024 program to learn more about this presentation, “Towards carbon-dioxide negative building composites,” and more scientific presentations.
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Title Towards carbon-dioxide negative building composites
Abstract Carbon capture utilization and storage require new approaches to CO2 sequestration, namely ones that could safely, and profitably sequester hundreds of thousands of tonnes of CO2 per year while finally being able to return the all-elusive profit. We present here, a new CCUS approach that produces CO2-negative composites, comprised of lignin or lignite fillers that have been functionalized with CO2, where they are mixed within a high-density polyethylene (HDPE) matrix. CO2 fixation at the particle’s surface is achieved by base-mediated Kolbe-Schmitt reactions, resulting in a durable C-C bond on polyphenols in lignin and lignite. After acidification, the carboxylation stores approximately 2-5% CO2 by weight on the particles. Manufacturing of the composites was performed using conventional injection molding with 50 wt.% filler, and a new shear-assisted processing and extrusion process with 80 wt.% filler. In each approach, the produced composites have mechanical properties that meet international building codes for decking, which represents a multi-billion-dollar market that could sequester hundreds of thousands of tonnes of CO2 per year. We present a full techno-economic and life cycle assessment of an envisioned process, detailing how composites produced with recycled HDPE and renewable energy provide favorable economics and a negative global warming potential over a twenty-year period. We conclude with a discussion of the remaining scientific and manufacturing efforts needed for commercialization and an assessment of other serviceable markets in which composites could be produced.
Developing bifunctional catalyst performance enhancement technology that will dramatically lower the cost of hydrogen production
Overcoming the durability limits of bifunctional catalysts for simultaneous hydrogen and oxygen production. Presenting large area reactor drive technology for commercialization of electrochemical systems.
Dr. Hyung-Suk Oh and Dr. Woong-Hee Lee of the Clean Energy Research Center at the Korea Institute of Science and Technology (KIST), in collaboration with POSTECH and Yonsei University, have developed a methodology to improve the reversibility and durability of electrodes using bifunctional platinum-nickel alloy catalysts with an octahedral structure that exhibits both oxygen reduction and generation reactions.
Bifunctional catalysts are a new generation of catalysts that simultaneously produce hydrogen and oxygen from water using a single catalyst. Currently, electrochemical systems such as water electrolysis technology and CCU (carbon dioxide capture and utilization) utilize separate catalysts for both electrodes, resulting in a high unit cost of hydrogen production. On the other hand, bifunctional catalysts that can be synthesized in a single production process are attracting attention as a technology that can reduce production costs and increase the economic efficiency of electrochemical energy conversion technologies.
However, the problem with bifunctional catalysts is that after each electrochemical reaction that generates hydrogen and oxygen, the performance of other reactions decreases due to structural changes in the electrode material. Therefore, in order to commercialize bifunctional catalysts, it is important to secure reversibility and durability that can maintain the catalyst structure for a long time after the reaction.
To enhance the reversibility and durability of the bifunctional catalyst, the team synthesized alloy catalysts with different structures by mixing platinum and nickel, which have high performance in oxygen reduction and generation reactions, respectively. The experimental results showed that the nickel-platinum interaction was most active in the octahedral structure, and the alloy catalysts performed more than twice as well as the platinum and nickel monoliths in oxygen reduction and generation reactions.
The researchers identified platinum oxide generated during the repeated generation reaction of the alloy catalyst as the cause of the performance degradation and developed a structure restoration methodology to reduce platinum oxide to platinum. The team confirmed through transmission electron microscopy that the methodology restored the catalyst's shape, and in large-area reactor experiments for commercialization, the team succeeded in restoring the catalyst shape and more than doubled the run time.
The team's bifunctional catalysts and structure recovery methodology are expected to accelerate the commercialization of unitized renewable fuel cells (URFCs) technology by replacing the separate catalysts for oxygen evolution and reduction reactions with bifunctional catalysts. URFCs that can produce both hydrogen and electricity can lower production costs by reducing the input of expensive catalysts while maintaining performance.
"The technology to improve the reversibility and durability of catalysts has provided a new direction for the development of bifunctional catalysts
Structural changes of platinum at each reaction step using X-ray photoelectron spectroscopy and in-situ X-ray absorption spectroscopy, which is an important technology for electrochemical energy conversion systems," said Hyung-suk Oh, lead researcher at KIST. "It will contribute to the commercialization and carbon neutrality of electrochemical systems such as URFCs in the future.“
KIST was established in 1966 as the first government-funded research institute in Korea. KIST now strives to solve national and social challenges and secure growth engines through leading and innovative research. For more information, please visit KIST’s website at https://eng.kist.re.kr/
This research was supported by the Ministry of Science and ICT (Minister Lee Jong-ho) under the 'KIST Institutional Program', 'Carbon to X Project' (2020M3H7A109822921), and 'Creative Convergence Research Project' (CAP21013-100) of the National Research Council of Korea (Chairman Kim Bok-cheol). The results were published in the latest issue of the prestigious international journal Advanced Energy Materials (IF: 27.8, top 2.5% in JCR) and were selected for the back cover image.
