As part of an effort to overcome the long-term energy-storage challenge, University of Wisconsin-Madison engineers have invented a water-soluble chemical additive that improves the performance of a type of electrochemical storage called a bromide aqueous flow battery.

“Bromide-based aqueous flow batteries are a promising solution, but there are many messy electrochemical problems with them. That’s why there’s no real successful bromide-based products today,” says Patrick Sullivan who graduated from UW-Madison with a PhD in chemistry in 2023. “Yet, our one additive can solve so many different problems.”

Sullivan, PhD student Gyohun Choi, and Dawei Feng, an assistant professor of materials science and engineering at UW-Madison, developed the additive. The research was published on October 23, 2024, by the journal Nature.

Currently, giant tractor-trailer-sized lithium-ion battery packs store energy for the grid — but with technical limitations. Lithium batteries have safety concerns due to the potential for fires and explosions and a complicated international supply chain.

Aqueous flow batteries, however, could make grid-scale storage safer and cheaper. In these batteries, positive and negative liquid electrolytes circulate over electrodes that are separated by a membrane. Since the batteries use ions dissolved in a liquid — water — they can be scalable, sustainable and safe.

The most commercially mature flow batteries are based on vanadium ions, which, like lithium, are expensive and hard to source. However, another version of these flow batteries relies on bromide, a cheap, widely available ion that performs similar to vanadium — at least on paper.

In practice, however, tiny bromide ions cause all sorts of problems in flow batteries. They can pass through the membrane that separates the electrodes, and that reduces the battery’s efficiency. Sometimes the ions precipitate out of the electrolyte and form a messy oil that “sinks” to the bottom of the solution. Occasionally, the ions also form toxic bromine gas. These issues hinder practical performance and reliability.

An additive called a complexing agent could help. Choi set out to find an additive that enhances bromide aqueous flow battery performance. The researchers used molecular design to engineer over 500 candidate organic molecules they call “soft-hard zwitterionic trappers.” They synthesized and tested 13 of these representative molecules as potential additives for the bromide batteries.

The resulting multi-functional additives solve the flow battery’s main problems. It encapsulates the bromide ions while allowing them to remain water-soluble, and since the resulting complex is now larger, they can’t pass through the membrane. The ions are also “phase-stable,” which means they don’t separate out of the water electrolyte or create toxic bromine gas.

Importantly, the additives dramatically improve the flow battery’s performance, increasing the efficiency and longevity of the chemical system. “Our devices with the additive functioned without decay for almost two months compared to ones without it, which typically fail within a day,” says Feng. “This is important because for green energy storage, you want to use it for 10 or 20 years.”

The team plans to continue refining the work. Choi will study the fundamental science behind additives for bromide and iodide flow batteries, while Sullivan, who is CEO of Flux XII — a renewable energy spinoff company he co-founded with Feng — will explore the commercial viability of the additive, which has already been successfully produced in industrial ton-scale reactions.

Dawei Feng is the Y. Austin Chang Assistant Professor in materials science and engineering. Other UW-Madison authors include Xiu-Liang Lv, Wenjie Li, Kwanpyung Lee, Haoyu Kong, Sam Gessler, and JR Schmidt.

The study analysed a 4.45 billion-year-old zircon grain from the famous Martian meteorite NWA7034, also known as Black Beauty, and found geochemical ‘fingerprints’ of water-rich fluids.

Study co-author Dr Aaron Cavosie from Curtin’s School of Earth and Planetary Sciences said the discovery opened up new avenues for understanding ancient Martian hydrothermal systems associated with magmatism, as well as the planet’s past habitability.

“We used nano-scale geochemistry to detect elemental evidence of hot water on Mars 4.45 billion years ago,” Dr Cavosie said.

“Hydrothermal systems were essential for the development of life on Earth and our findings suggest Mars also had water, a key ingredient for habitable environments, during the earliest history of crust formation.”

“Through nano-scale imaging and spectroscopy, the team identified element patterns in this unique zircon, including iron, aluminium, yttrium and sodium. These elements were added as the zircon formed 4.45 billion years ago, suggesting water was present during early Martian magmatic activity.”

Dr Cavosie said the research showed that even though Mars’ crust endured massive meteorite impacts that caused major surface upheaval, water was present during the early Pre-Noachian period, prior to about 4.1 billion years ago.

“A 2022 Curtin study of the same zircon grain found it had been ‘shocked’ by a meteorite impact, marking it as the first and only known shocked zircon from Mars,” Dr Cavosie said.

“This new study takes us a step further in understanding early Mars, by way of identifying tell-tale signs of water-rich fluids from when the grain formed, providing geochemical markers of water in the oldest known Martian crust.”

Lead author Dr Jack Gillespie from the University of Lausanne was a Postdoctoral Research Associate at Curtin’s School of Earth and Planetary Sciences at the time of the study, which was co-authored by researchers from Curtin’s Space Science and Technology Centre, the John de Laeter Centre and the University of Adelaide, with funding from the Australian Research Council, Curtin University, University of Adelaide and the Swiss National Science Foundation.

The full study, titled ‘Zircon evidence for early hydrothermal activity on Mars’, will be published in Science Advances.

“The network of canals was designed to channel annual flood waters into source ponds for fish trapping and would have yielded enough fish to feed as many as 15,000 people year-round, conservatively,” said Eleanor Harrison-Buck, professor of anthropology and director of the Belize River East Archaeology (BREA) project. “The dates indicate that the fisheries were initially constructed by Late Archaic hunter-gatherer-fishers and continued to be used by their Formative Maya descendants (approximately 2000 BCE to 200 CE). For Mesoamerica in general, we tend to regard agricultural production as the engine of civilization, but this study tells us that it wasn’t just agriculture — it was also potential mass harvesting of aquatic species.”

Published in the journal Science Advances, the research used 26 radiocarbon dates from test excavation sites in the CTWS, which indicate that such landscape-scale wetland enhancements may have been an adaptive response to long-term climate disturbance recorded in Mesoamerica between 2200 and 1900 BCE.

“The early dates for the canals surprised us initially because we all assumed these massive constructions were built by the ancient Maya living in the nearby city centers,” said Harrison-Buck. “However, after running numerous radiocarbon dates, it became clear they were built much earlier.”

Sediment samples were collected along the walls of the excavation units and sequenced for specific elements, such as nitrogen and carbon, to look for environmental changes over time. The sediment showed a strong tropical forest dominance during that period and no evidence of crop cultivation, specifically maize. Along with a lack of any pollen from domesticated crops, there were not any signs of ditched and drained agricultural fields in the immediate area dating to that time. The multiproxy data gathered suggests the distinctive long linear zigzag channels served primarily as large-scale fish-trapping facilities.

“It seems likely that the canals allowed for annual fish harvests and social gatherings, which would have encouraged people to return to this area year after year and congregate for longer periods of time,” said Marieka Brouwer Burg, professor of anthropology at the University of Vermont and BREA co-director. “Such intensive investments in the landscape may have led ultimately to the development of the complex society characteristic of the pre-Columbian Maya civilization, which subsequently occurred in this area by around 1200 BCE.”

“Wetlands have always been a critical ecosystem for humans across the globe,” said Samantha Krause, professor of geography and environmental studies at Texas State University. “Knowing how to manage wetland resources responsibly is essential for the continued resilience of these ecosystems both in the past and today. The Archaic hunter-gatherer-fishers knew how to protect their resources and use them in a way that could sustain these habitats, not exhaust them, which explains their long-lasting occupation in this area.”

With the support of the local community, the team plans to return to Crooked Tree to investigate a larger sample of these landscape-scale modifications that they have identified across a broad area of northern Belize, hoping to more fully understand the complexity of human-wetland interactions in the past.

Other co-authors include Mark Willis, department of archaeology, Flinders University, Adelaide, South Australia; Angelina Perrotti, Palynology & Environmental Archaeology Research Lab; Monona, Wisconsin; and Katie Bailey, department of anthropology, University of Vermont.

This research was funded by a grant from the Alphawood Foundation Chicago. Additional support was provided by a collaborative research grant from the National Science Foundation. The Belize Institute of Archaeology provided an archaeological permit, granting permission to excavate in the Crooked Tree Wildlife Sanctuary. The Crooked Tree Village Council welcomed the research team and permitted them to map and excavate in the wetlands around their community.

The research, which was published in the journal Proceedings of the National Academy of Sciences (PNAS), offers a promising target for future therapies.

Hidradenitis suppurativa (HS) is an immune disease that affects up to 4% of the global population and causes painful, recurring skin lesions and inflammation, primarily in the folds of the skin. It commonly affects women of African American descent.

Shahid Mukhtar and his team — Bharat Mishra, Nilesh Kumar and graduate student YiFei Gou — used single-cell sequencing techniques to pinpoint CD2 as a key immune receptor with elevated expression on T cells and innate lymphoid cells (ILCs), including natural killer cells, in HS-affected skin tissue.

In collaboration with researchers at the University of Alabama at Birmingham, Mukhtar’s team demonstrated through organotypic skin culture experiments from HS patients that blocking CD2 led to a significant reduction in cytokine and chemokine production, along with suppression of key pathogenic gene signatures.

This finding suggests that blocking CD2 may effectively reduce the inflammatory response in HS, providing a potential new therapeutic avenue for managing symptoms and improving patient quality of life.

Gou, who has a keen interest in deep learning, a type of artificial intelligence (AI), hopes to further integrate single-cell transcriptomics with global protein-protein interactions using contextual AI. This approach aims to enhance understanding of cellular networks and disease mechanisms, pushing forward the frontiers of precision medicine for immune-related diseases like HS.

“Our integrative approach, combining single-cell data with molecular insights, shows the transformative potential of multiomics in discovering novel therapeutic targets,” Mukhtar said. “These findings deepen our understanding of HS and open new pathways for developing targeted therapies in HS and other immune-related conditions.”

This discovery has far-reaching implications for our understanding of past climate variability and future climate change. However, lead author and junior professor Dr Sebastian Sippel from Leipzig University stresses that the new findings do not affect the quantification of the global warming relative to 1850-1900 and the human contribution to that warming: the land and ocean temperatures of the 19th century (1850-1900), before the onset of the cold period, provide a physically very consistent picture of temperature changes up to the present day. Nevertheless, correcting this cold period could increase confidence in the amount of observed warming, changing what we know about historical climate variability and improve the quality of future climate models.

Understanding global temperature trends is crucial for climate research. Dr Sebastian Sippel, Junior Professor for Climate Attribution at Leipzig University, worked with international scientists to reconstruct the global mean temperature from historical climate data like a jigsaw puzzle — including historical land and ocean measurements and palaeoclimatic analyses. When comparing land and ocean, Sippel noticed a systematic deviation: at the beginning of the 20th century, ocean temperatures were lower than in previous decades, while over land air temperatures remained relatively constant. This outcome is not consistent with physical theory and climate models.

New explanations for past phenomena

Using many different lines of evidence, the new study shows that reconstructions of the global mean temperature from ocean surface data for this period are too cold: on average about 0.26 degrees Celsius colder than seen in land-based reconstructions. This discrepancy is greater than what would be possible under natural climate variability. “Our latest findings do not change the long-term warming since 1850. However, we can now better understand historical climate change and climate variability,” says junior professor Dr Sebastian Sippel. For example, the reasons for the early 20th century warming period between 1900 and 1950 have never been fully understood. If the ocean temperatures are corrected, the warming trend of the early 20th century is weaker. “The discrepancies between the climate models and the observed temperature trend at the beginning of the 20th century are mainly due to an incomplete understanding of the observations, rather than incomplete climate models or natural climate variability. There are well-established approaches to account for the effects of changing measurement methods on ocean surface temperature measurements. The new research shows that in the early 20th century these methods don’t properly account for very rapidly changing differences in the way the observations were made. Our new understanding confirms the climate models and shows even more clearly the human impact since pre-industrial times,” says co-author Professor Reto Knutti, Professor for Climate Physics at ETH Zurich.

A multidimensional approach

The study itself offers indications that the cause of the ocean cold anomaly could lie in insufficiently documented information about the measurement techniques used at that time. Before the Second World War, ocean temperatures were mainly measured with buckets on ships, but the method of measurement and the composition of ship fleets changed from decade to decade, making it much more difficult to correct for systematic measurement errors. The authors of the study therefore recommend a variety of approaches to data processing and analysis: “Our methodological approach emphasises the need to continuously rescue and digitise historical climate data and compare it with independent data. At the same time, very different assumptions regarding systematic adjustments of early climate data should be tested, as the observational data are of central importance as a basis for climate understanding and modelling,” says Sippel.

The ability of the human heart to renew itself by regenerating its muscle cells, myocytes, is very limited. But what happens to this capability when the heart is damaged by severe heart failure has been unknown.

Researchers at Karolinska Institutet have now discovered that after an injury, the rate of cell renewal is even lower than in a healthy heart. Standard-of-care for patients with advanced heart failure is a surgically implanted pump that helps propel blood, a so-called left ventricular assist device (LVAD).

Kick-start the repair mechanism

Surprisingly, the researchers found that patients with such a heart pump, who have shown significant improvement in their heart function, can regenerate heart muscle cells at a rate more than six times higher than in healthy hearts.

“The results suggest that there might be a hidden key to kick-start the heart’s own repair mechanism,” says Olaf Bergmann, senior researcher at the Department of Cell and Molecular Biology at Karolinska Institutet and last author of the paper.

The mechanism behind the effect is still unknown and there is not yet any hypothesis to explain it.

“It is difficult to say. In the existing data we cannot find an explanation for the effect, but we will now continue to study this process at a cellular and molecular level,” says Olaf Bergmann.

The findings open the possibility of developing new therapies for patients with serious heart conditions that stimulate the heart’s ability to repair itself after damage. This way, patients wouldn’t have torely only on heart transplants or other kinds of long-term mechanical support.

“This offers some hope that the recovery after a heart incident can somehow be boosted,” says Olaf Bergmann.

Determine the age of cells

It is generally difficult to determine the age of cells in the human body and to decide which cells are new and which are old. However, by using a method earlier devised by Jonas Frisén, professor of stem cell research at Karolinska Institutet, the group has been able to count the rate of renewal of myocytes in the heart. The method is based upon the fact that the percentage of radioactive carbon in the atmosphere, and subsequently in our cells, has steadily decreased since the nuclear test ban in 1963. For every following year, there is a little less radioactivity in newly formed cells, which means that they can be ‘dated’.

The study was done in close collaboration with Stavros Drakos at the University of Utah, USA, and was mainly financed by the Swedish Research Council, LeDucq Foundation and the Ragnar Söderberg Foundation. There are no reported conflicts of interest.