P2X-catalyst needs less Iridium

But new options are already in the pipeline: Within the Kopernikus P2X project, a new efficient iridium-based nanocatalyst was developed by the Heraeus Group, consisting of a thin layer of iridium oxide deposited on a nanostructured titanium dioxide support. The so-called ‘P2X catalyst’ requires only an extremely small amount of iridium, reducing precious metal loading substantially (four times lower than in the current best commercial material).

A team at HZB led by Dr. Raul Garcia-Diez and Prof. Dr.-Ing. Marcus Bär, together with colleagues from the ALBA synchrotron in Barcelona, have studied the P2X catalyst, which shows remarkable stability even in long-term operation, and compared its catalytic and spectroscopic signature with the benchmark commercial crystalline catalyst.

Operando measurements at BESSY II

The HZB team has thoroughly investigated the commercial benchmark catalyst as well as the P2X catalyst at BESSY II during water electrolysis (operando measurements). “We wanted to observe how the two different catalyst materials change structurally and electronically during the electrochemical oxygen evolution reaction using operando Ir L₃-edge X-ray absorption spectroscopy (XAS),” says Marianne van der Merwe, a researcher in Bär’s team. They also developed a new experimental protocol to ensure that the results are measured in both samples under exactly the same oxygen production rate. This made it possible to compare the two catalysts under equivalent conditions.

Different chemical environments explored

“From the measurement data, we were able to conclude that the mechanisms for OER in the two classes of iridium oxide catalysts are different, and this is driven by the different chemical environments of the two materials,” says van der Merwe. The measurement data also show why the P2X catalyst performs even better compared to its more crystalline benchmark: in the P2X sample, the bond lengths between iridium and oxygen decrease significantly more than in the reference catalyst at OER relevant potentials. This reduction in Ir-O bond lengths can be associated to the participation of defective environments that are proposed to be key players in highly active pathways of the oxygen evolution reaction.

“In addition, the electronic state observations also correlate with local geometric information,” van der Merwe points out. “Our work provides valuable key information about the different mechanisms of iridium oxide-based electrocatalysts during the oxygen evolution reaction and deepens our understanding of catalyst performance and stability, while our newly proposed in situ spectroscopic electrochemical protocol approach is generally applicable to all anode materials studied under relevant OER conditions.”

“Tell me why: The missing w in episodic memory’s what, where and when” appears in a special issue of Cognitive, Affective & Behavioral Neuroscience focusing on individual differences in memory modulation. Authors Fernanda Morales-Calva, a graduate student in psychological sciences at Rice, and Stephanie Leal, an adjunct assistant professor of psychological sciences, examined existing research to create a comprehensive analysis of the “three Ws” of memory — what, where and when we remember — to answer the central question of why people remember.

Specifically, the researchers explore how emotional significance, personal relevance and individual differences shape memory retention. Unlike experimental studies, this review gathers and interprets existing findings to advance the understanding of episodic memory.

The review categorizes memory research into three primary domains centered on what, where and when people remember. Morales-Calva and Leal found that memories are often shaped by emotional content, personal significance, repetition and attention. For example, individuals are more likely to remember events with deep emotional resonance or details on which they actively focus.

However, what we remember is also influenced by factors such as where the event happened. What is known as spatial memory is often studied in animals, and the researchers said it is also an important aspect of what we remember that applies to human experiences. New environments command greater attention and therefore foster stronger memories when compared to familiar, routine settings.

Finally, the researchers said when the event occurs makes a difference in what people remember. How individuals sequence events and recognize transitions between them plays a critical role in memories. Specific events are often compartmentalized into distinct episodes and therefore can be easier for individuals to recall.

In addition to the what, where and when of memory, Morales-Calva said individual circumstances, including cultural, personal and cognitive differences, can have a significant impact in shaping how individuals remember.

“Memory is not a one-size-fits-all phenomenon,” Morales-Calva said. “What’s memorable for one person might be entirely forgettable for another depending on their unique background and cognitive priorities.”

The researchers said that examining why we remember certain experiences over others can have significant implications for both clinical and everyday settings. For instance, professional memory assessments often rely on standardized tests developed in specific cultural contexts, which have the potential to overlook critical individual differences, the researchers said. Such tests may yield skewed results when applied in diverse populations, highlighting the need for more tailored approaches.

As the global population ages and memory impairments become increasingly prevalent, understanding the specific factors that shape memory could inform interventions for conditions like dementia and cognitive decline, the researchers said.

“This review highlights the importance of considering subjectivity and context in memory research,” Leal said. “By accounting for these variables, we can develop more accurate diagnostic tools and effective interventions.”

The authors argue that complexity of memory can be better understood when the researchers incorporate individual differences into experimental designs. By doing so, they say they hope to bridge gaps between laboratory findings and real-world applications to foster a deeper understanding of the human experience.

The findings, which have been published in the journal Parasitology, present some of the earliest evidenceof schistosomiasis outside its endemic region of Africa.

“Many of the parasites we see today have been around for centuries. One of our goals in infectious disease studies is to understand where in the world people had these parasites in the past and how their epidemiology has changed through time,” says Marissa Ledger, a post-doctoral fellow at McMaster’s Ancient DNA Centre, who led the research.

Schistosomiasis is caused by Schistosoma mansoni, a water-borne parasitic flatworm that can burrow into the skin, move through the bloodstream and establish itself in the intestines. There it reproduces and releases eggs, which are passed through human waste. Ledger discovered a preserved egg in the contents of a 15^th-century latrine in present-day Belgium, thousands of kilometers away from its endemic region.

The latrine had been uncovered in an excavation in 1996, but its artifacts and organic remains were only recently examined as part of a larger research project at Ghent University focused on the many foreign communities living and trading in medieval Bruges and its former harbor towns.

Researchers say the latrine came from a house known as the Spanish nation house, the administrative seat and meeting place of the Castilian merchant community. The parasite in question is likely associated with one of these Spanish traders who facilitated the import of African commodities like gold dust, ivory and various spices. There’s also evidence they were involved in the early Atlantic slave trade.

The combination of this rich historical record with the archaeological and parasitological data is quite unique and helps us better understand human migration and disease transmission in the past and underscores the historical significance of this Belgian-Canadian collaboration.

“Our findings speak to the complexity of medieval urban life and how interconnected this world was centuries ago. It not only provides novel insight into daily life of people in medieval Bruges but also shows how the city, known as an international hub for people, goods and ideas, inevitably also facilitated the spread of diseases through its strong maritime trade networks,” says Maxime Poulain, archaeologist at Ghent University.

It also demonstrates the importance of analyzing organic remains from these types of archaeological finding, as it can provide information on the health, hygiene and mobility of populations.

Ledger plans to analyze the genetics of the parasite to understand how its makeup compares to that of its modern counterparts.

“Understanding these parasites over a broader time frame provides more information on how they are impacted by factors like migration. Even in the past as people were migrating over these long distances, they were still very effectively moving infectious diseases across long distances. That’s incredibly useful to know.”

The CAST/EiJ mouse, part of a research panel including eight genetically diverse mouse strains, stands out for its severe response to SARS-CoV-2 infection, including beta, omicron, and delta variants. While other strains either recovered or showed mild symptoms, the CAST mice displayed acute illness, highlighting their unique susceptibility to the virus.

“Although most mice strains have negligible symptoms from infection with SARS-CoV-2 variants, CAST mice exhibit a lethal response, making them an invaluable resource for studying the virus’s impact and testing next-generation therapies,” said Nadia Rosenthal, scientific director and professor at JAX, and one of the senior authors of the study.

Originally collected on the island of Castania and brought to JAX in 1971, CAST mice were bred at JAX to maintain a genetically pure line, creating a model as true to the mouse genome as possible. This characteristic makes them an ideal model for investigating severe COVID-19 symptoms on a clean genetic background.

These mice not only carry high viral loads in the lungs but also display severe lung damage, mirroring the kind of hyperinflammatory response seen in human patients with severe COVID-19. This unique strain offers researchers a model that closely parallels the human response to the virus without brain infection — an issue in previous models of COVID-19.

Initial trials using antiviral treatments have shown promising results, boosting survival rates in CAST mice and sparking hope for their role in developing therapies for future coronavirus outbreaks. As new variants continue to emerge, the CAST mouse model stands ready to accelerate a response, providing insights that could ultimately save lives.

Diversity in mouse models offers new perspectives

The study explored eight genetically diverse mouse strains, including A/J, B6J, CAST, 129S1, NSG, NZO, PWK, and WSB, encompassing traits like type 1 and type 2 diabetes susceptibility, obesity, and leanness. These diverse genetic backgrounds enabled the team to uncover differences in virus susceptibility.

Rosenthal and Candice Baker, director of research projects at JAX and first author of the study, started with all eight strains of mice and found the CAST mouse stood out as a highly susceptible mouse for Sars-CoV-2 infection. While the CAST mice didn’t recover, some strains did but displayed lingering symptoms resembling long-COVID.

“The CAST mice gave us insight into the acute symptoms of COVID-19, but now we are going to look at the long-term effects,” said Baker.

In follow-up work, Rosenthal and Baker plan to investigate long-term impacts using this same panel of eight mice.

Overcoming the early challenges of COVID-19 research

When the pandemic began, traditional mouse models were unsuitable for SARS-CoV-2 research, as their cells lack the receptors needed for the virus to bind. In 2023, Rosenthal and her team at JAX and NIH’s Rocky Mountain Laboratories addressed this by using mice engineered with human versions of these receptors, but the resulting infections were overly severe and failed to mimic the spectrum of human responses.

By crossing genetically engineered mice with diverse strains, Rosenthal’s team replicated a range of human-like responses. But these engineered human receptors don’t always give a clinically relevant disease phenotype. The CAST mouse is invaluable, as its genetic background avoids artificial receptor modifications, making it a more natural model for studying severe COVID-19.

“CAST mice stand poised to transform COVID-19 research and prepare us for future challenges,” said Rosenthal. “Equally important, the work reinforces the critical role of genetic diversity in science.”

Current strains of the bovine (cow) H5N1 virus are not known to be transmissible among people; however, infections have occurred in people exposed to infected wild birds, poultry, dairy cows and other mammals. As part of pandemic preparedness efforts, researchers have monitored the H5N1 virus for years to understand viral genetic mutations that occur in nature and what impact they may have on transmissibility.

Influenza viruses attach to cells with a surface viral protein called hemagglutinin (HA). The HA latches on to sugar (glycan) molecule receptors on cells to cause infection. Avian (bird) influenza viruses — like H5N1 — have not infected people often because the human upper respiratory tract lacks the avian-type cell receptors found in birds. Scientists are concerned that viruses could evolve to recognize human-type cell receptors in the upper airways and acquire the ability to infect people and spread between them.

Scientists at Scripps Research used the H5N1 strain isolated from the first U.S. human infection with the bovine strain 2.3.4.4b (A/Texas/37/2024) to test how mutations in the HA gene sequence affected the binding of that protein with avian versus human-type cell receptors. The researchers introduced several mutations into the viral HA protein that had been observed to occur naturally in the past and found that one mutation, called Q226L, improved the ability of the protein to attach to receptors typically found on human cells, especially when an additional mutation was present. Importantly, the researchers introduced the genetic mutations only into the HA surface protein and did not create or conduct experiments with a whole, infectious virus.

The experimental finding with the Q226L mutation alone does not mean HPAI H5N1 is on the verge of causing a widespread pandemic, the authors note. Other genetic mutations would likely be required for the virus to transmit among people. In the setting of a growing number of H5N1 human cases resulting from direct contact with infected animals, the findings stress the importance of continued efforts at outbreak control and continued genomic surveillance to monitor for the emergence of HPAI H5N1 genetic changes and maintain public health preparedness.

The research was funded in part by NIH’s National Institute of Allergy and Infectious Diseases (NIAID), through its Centers of Excellence for Influenza Research and Response program.

Akbulut and his research group have developed an innovative pesticide delivery system called nanopesticides. These tiny technologies, developed through a collaboration between Texas A&M University’s engineering and agricultural colleges, Dr. Luis Cisneros-Zevallo, professor of Horticultural Science and Dr. Younjin Min, professor of Chemical Environ Engineering at University of California, Riverside, could change how we use pesticides.

“The U.S. is a world leader in agricultural production, feeding not just our nation but much of the world. Yet we are using pesticides in a way that is simply not sustainable — with a substantial fraction not reaching its intended target,” said Akbulut. “Our research shows that by optimizing the surface chemistry of pesticide carriers, we can make these essential crop protection tools more efficient.”

The team studied different types of nanopesticide carriers, testing their “stickiness” to pepper leaves, a representative model for many important crops. They discovered that the carrier’s surface chemistry plays an important role in how well the nanopesticide adheres to the plant.

Nanopesticides encapsulate the active pesticide ingredients within microscopic carriers. Think of it like delivering a targeted package directly to the pest, minimizing collateral damage. This research focused on understanding how these nanopesticides interact with plant surfaces, a crucial step in maximizing their effectiveness.

Pesticides are essential for protecting crops from pests and diseases, and without them, we would lose a huge portion of our harvests — up to 70-80% of fruits, 40-50% of vegetables, and 20-30% of cereals.

However, current pesticide application methods are incredibly inefficient. More than 80-90% of sprayed pesticides miss their target entirely, ending up in the environment where they can cause harm. This waste is not only bad for the planet, but it is also economically unsustainable.

This compound, which Akbulut and Yashwanth Arcot, Ph.D candidate discuss in their paper published in Surfaces and Interfaces Journal, is a mixture of Ethyl Lauroyl Arginate (ELA), a food preservative compound, and neem seed extract.

Arcot’s interest in the research focuses on nanopesticide chemistry to ensure a higher targeting ability and the strong correlation between the nanopesticide carrier and its adsorption behavior.

Akbulut believes that by using nanopesticide, he can increase the efficacy by better targeting the plant surface. Akbulut and his team aim to achieve this by taking various pesticides and modifying their interfacial properties using carriers that are best suited to interact with the plant surface characteristics.

Overall, the goal of the research is to find a way for more efficient and environmentally friendly pesticide formulations that are sustainable for agricultural practices and global food security.

“This study addresses a critical challenge in sustainable agriculture by optimizing nanopesticide systems to enhance efficacy, reduce environmental pollution, and minimize impacts on non-target organisms and human health,” Arcot said.

Neem seed is a naturally occurring pesticide that comes from the seeds of the neem tree and is used to control pests and diseases on crops. The extract from a neem seed tree grows mostly in India but is organic pesticide management.

“Organic pesticides use this formulation, and we also use this molecule in the center. Although the carriers are different, the active ingredient inhibits or inactivates the pest.”

According to the paper, among various types of pesticides, nanopesticides have shown to be an advanced crop protection strategy that relies on agricultural technology, nanotechnology, and materials chemistry.

Akbulut said this discovery has profound implications for the future of agriculture. By tailoring the surface chemistry of nanopesticides, scientists can optimize their effectiveness, ensuring that more of the pesticide reaches the target pest and less ends up polluting the environment.

“For farmers or industry who are using the pesticides, they will clearly understand the value of this research,” Akbulut said. “Pesticides, in general, are considered bad for the environment, using neem seed extract ensures crop survival from pests and is non-toxic for consumption.”

The MARCO study — MAgnetic Resonance Imaging in COliac disease — which is published in Clinical Gastroenterology and Hepatology (CGH), was led by experts from the School of Medicine at the University of Nottingham, alongside colleagues at the Quadram Institute.

Coeliac disease is a chronic condition affecting around one person in every 100 in the general population. When people with coeliac disease eat gluten, which is found in pasta and bread, their immune system produces an abnormal reaction that inflames and damages the gut tissue and causes symptoms such as abdominal pain and bloating.

The only treatment is a life- long commitment to a gluten free diet, which helps recovery of the gut tissue but still leaves many patients with gastrointestinal symptoms.

Luca Marciani, Professor of Gastrointestinal Imaging at the University, led the study. He said: “Despite being a common chronic condition, we still don’t precisely know how coeliac disease affects the basic physiological functioning of the gut and how the gluten free diet treatment may further change this.

“We launched the MARCO study to try and address this issue, by using MRI along with gut microbiome analysis to give us new insights into how a gluten-free diet affects people with coeliac disease.”

The team recruited 36 people who had just been diagnosed with coeliac disease and 36 healthy volunteers to participate in the study. Images were taken of their guts with MRI, along with blood and stool samples. The patients then followed a gluten free diet for one year and came back to repeat the study. The healthy participants came back one year later too and repeated the study, but they did not follow any diet treatment.

The study found that the newly diagnosed patients with coeliac disease had more gut symptoms, more fluid in the small bowel and that the transit of food in the bowel was slower than in the healthy controls.

The microbiota (the ‘bugs’ living in the colon) of the patients showed higher levels of ‘bad bugs’ such as E.coli. After one year of a gluten free diet, gut symptoms, bowel water and gut transit improved in the patients, but without returning to normal values. By contrast, the gluten free diet reduced some of the ‘good bugs’ in the microbiota, such as Bifidobacteria associated with reduced intake of starch and wheat nutrients, due to the different diet.

The patient study was conducted by Radiographer Dr Carolyn Costigan, from Nottingham University Hospitals, as part of her PhD studies at the University of Nottingham.

Professor Marciani said: “It was particularly interesting to see how the imaging results on gut function correlated with changes in the ‘bugs’ in the colon microbiota. The findings increase our understanding of gut function and physiology in coeliac disease and open the possibility of developing prebiotic treatments to reverse the negative impact of the gluten free diet on the microbiome.”

Dr Frederick Warren from the Quadram Institute said: “This study is the result of an exciting and innovative research collaboration bringing together medical imaging technology and gut microbiome analysis. We provide important insights which pave the way for future studies which may identify novel approaches to alleviate long-term symptoms in coeliac patients.”

Harte et al’s paper in PNAS, published on December 6, outlines their approach and provides four pared-down examples where it could be applied.

“Over the past 14 years, we have written a series of papers showing that in ecology, this top-down approach is very powerful and reveals patterns in ecosystems,” says Harte. “It accurately predicts ecological patterns such as the species-area relationship (how diversity increases with plot area) and the distribution of abundances and body sizes of species. But six years ago, we discovered that when an ecosystem is heavily disturbed — and as a result, the system-level properties are in flux — then the top-down approach fails miserably.” And so, Harte and his colleagues set out to develop a theory that could describe both the system-level dynamics and the probability distributions that characterize the system components for complex systems in flux.

Disturbances and the two-way feedback they can cause show up in many types of systems. In the case of a pandemic, conventional bottom-up Susceptible-Infected-Recovered (SIR) equations help measure the probability that an individual could get sick through proximity to an infected person. What this approach doesn’t capture, though, is the interplay between the micro and macro scales. As cases of the disease rise at the macro level, individuals might take notice and change their behaviors, causing case levels to fall.

Similarly, in an economy, the decisions individuals make on whether or not to take a job or make a purchase are influenced by system-level properties like GNP growth and inflation rates. Meanwhile, consumer spending is a driving factor in the economy and can impact economic growth or decline.

In 2021, Harte and colleagues first presented their new approach in the journal Ecology Letters with their paper “DynaMETE: a hybrid MaxEnt-plus-mechanism theory of dynamic macroecology.” Testing their theory against data from a heavily disturbed forest in Panama, the team showed that their hybrid model could explain changes in species distribution. Now, the authors generalize their model for possible application in other scenarios.

“This model allows us to calculate things that haven’t been calculable before,” says Harte. “In these bi-level systems, when there’s both top-down and bottom-up influence, how do you calculate, when the system is disturbed, how the system and the individuals will respond over time? There was not an adequate theory before. This theory allows us to predict the trajectory of the system-level variables and the probability distribution of individual parts in that system.”

Harte proposes a test of the theory in a combustion tank — a simple thermodynamic system — and says other tests are needed. “The biggest insight here was realizing the importance of the question. We think this theory is good, but it may not be right. It’s still got to be tested across many types of systems.”

In nonequilibrium thermodynamics such as the proposed combustion tank experiment, predicting the probability distribution of molecular kinetic energies has been a frontier issue. “It has resisted calculation,” says Harte.

The hybrid theory offers a new way to study dynamics, whether in controlled lab settings or in some of the most tantalizing and critical problems facing humanity, from climate change and pandemics to economic volatility.