Despite feeling like a stationary mass, most solid ground is undergoing a process of deformation, sinking and rising in response to many environmental factors. In Antarctica, melting glacial ice means less weight on the bedrock below, allowing it to rise. How the rising earth interacts with the overlying ice sheet to affect sea level rise is not well-studied, said Terry Wilson, co-author of the study and a senior research scientist at the Byrd Polar and Climate Research Center at The Ohio State University.

In the new study, Wilson’s colleagues at McGill University developed a model to predict how these interactions could impact global sea level, finding that if humans can lower greenhouse gas emissions and global warming is slowed, upward shifts in the solid earth could reduce Antarctica’s contribution to sea level rise by about 40%, significantly bolstering the best case scenarios for global sea level rise. In this low-emissions scenario, land uplift slows the flow of ice from land to ocean, allowing for more of the ice sheet to be preserved.

Conversely, if humans are unable to lower carbon emissions in time, ice retreat will outpace uplift, pushing ocean water away from Antarctica and amplifying sea level rise. These events could significantly worsen the most dire models of projected sea level rise along populated coastlines, said Wilson.

“Our measurements show that the solid earth that forms the base of the Antarctic ice sheet is changing shape surprisingly quickly,” said Wilson. “The land uplift from reduced ice on the surface is happening in decades, rather than over thousands of years.”

The study was published today in Science Advances.

To arrive at these conclusions, the team developed a 3D model of the Earth’s interior using geophysical field measurements from the Antarctic Network (ANET) of the Polar Earth Observing Network (POLENET) project. The mission is focused on studying the changing polar regions by collecting GPS and seismic data from an array of autonomous systems across Antarctica.

Researchers then performed a number of simulations to capture many possible evolutions of Antarctica’s ice sheet and the extent of global sea level rise Earth may experience until the year 2500, according to those parameters.

“We can project what difference it actually will make if we all contribute to a low-emission scenario now, versus what’s come to be called ‘business as usual’ emissions,” said Wilson, who is also the lead investigator of the ANET-POLENET project.

She attributes the model’s unprecedented level of detail to how deftly it incorporates data from Antarctica. GPS stations monitor how the land is moving and seismometers measure how fast seismic waves from earthquakes travel through the earth, yielding important insight into where the land uplift will be fast or slow.

Surprisingly, according to some of the team’s GPS observations processed by researchers at Ohio State, Wilson said, the Antarctic Ice Sheet is currently experiencing a solid earth uplift of about 5 centimeters per year, about 5 times the rate that North America experiences.

Another significant aspect of the study is how the changes in Antarctica under different carbon emissions scenarios will impact coastlines around the world. Because sea level change will not be uniform, the study notes that nearly 700 million people around the world living in coastal regions will be most impacted by rising seas due to Antarctic ice loss.

Since some regions, such as small island nations, will be more vulnerable than others, mitigating environmental conditions like atmospheric and ocean warming is a vital issue for society, said Wilson.

“Many people are now more aware they’re experiencing the effects of climate change,” she said. “This work reinforces that our actions as individuals, nations and globally can make a difference in what kind of Earth our offspring will experience in their lifetimes.”

The study results highlight how complex the relationship between the solid earth and the processes that happen atop it is, as well as the importance of continuing to gather enough data to make prompt and accurate predictions about what the next few centuries of our planet will look like.

“There’s a lot of uncertainty in every model and every prediction that you make,” said Wilson. “But to document how fast our world is changing, it’s very important to continue advancing our ability to make predictions that are more certain, which is the only path that will allow us to tend to our future in a meaningful way.”

Wilson completed the study with colleagues from McGill University, Pennsylvania State University, the University of Massachusetts Amherst, Columbia University, Washington University, Colorado State University and the Union of Concerned Scientists. This study was supported by the U.S National Science Foundation and the Natural Sciences and Engineering Research Council of Canada.

“The improvements we saw on both printability and mechanical measures suggest that incorporating cellulose nanofibrils in commercial printable materials could lead to more resilient and eco-friendly construction practices sooner rather than later,” said Osman E. Ozbulut, a professor in the Department of Civil and Environmental Engineering.

His team’s findings will be published in the September 2024 issue of Cement and Concrete Composites.

Buildings made of 3D-printed concrete are an exciting trend in housing, and they offer a slew of benefits: Quick, precise construction, possibly from recycled materials, reduced labor costs and less waste, all while enabling intricate designs that traditional builders would struggle to deliver.

The process uses a specialized printer that dispenses a cement-like mixture in layers to build the structure using computer-aided design software. But so far, printable material options are limited and questions about their sustainability and durability remain.

“We’re dealing with contradictory objectives,” Ozbulut said. “The mixture has to flow well for smooth fabrication, but harden into a stable material with critical properties, such as good mechanical strength, interlayer bonding and low thermal conductivity.”

Cellulose nanofibrils are made from wood pulp, creating a material that’s renewable and low impact. Like other plant-fiber derivatives, CNF, as the material is known in industry, shows strong potential as an additive to improve the rheology — the scientific term for flow properties — and mechanical strength of these composites.

However, until the UVA-led team’s meticulous study in Ozbulut’s Resilient and Advanced Infrastructure Lab, the influence of CNF on conventional 3D-printed composites wasn’t clear, Ozbulut said.

“Today, a lot of trial and error goes into designing mixtures,” he said. “We’re addressing the need for more good science to better understand the effects of different additives to improve the performance of 3D-printed structures.”

Experimenting with varying amounts of CNF additive, the team, led by Ozbulut and Ugur Kilic, now a Ph.D. alumnus of UVA, found that adding at least 0.3% CNF significantly improved flow performance. Microscopic analysis of the hardened samples revealed better material bonding and structural integrity.

In further testing in Ozbulut’s lab, CNF-enhanced 3D-printed components also stood up to pulling, bending and compression.

The finding is significant because the Antarctic Ice Sheet is the largest ice mass on Earth, and the biggest uncertainty in predicting future sea levels is how this ice will respond to climate change.

“With nearly 700 million people living in coastal areas and the potential cost of sea-level rise reaching trillions of dollars by the end of the century, understanding the domino effect of Antarctic ice melt is crucial,” said lead author Natalya Gomez, an Associate Professor in McGill’s Department of Earth and Planetary Sciences and Canada Research Chair in Ice sheet — Sea level interactions.

The study focuses on how the ice sheet interacts with the earth beneath, and how that dynamic is influenced by carbon-emission levels. This relationship has not been thoroughly explored in previous studies, the researchers said.

“Our findings show that while some sea level rise is inevitable, swift and substantive action to lower emissions could prevent some of the most destructive impacts of climate change, particularly for coastal communities,” Gomez said.

Rising seas and nature’s double-edged sword

As ice melts, its weight decreases, causing the land beneath it to rise like an expanding sponge. The researchers say this process, called post-glacial uplift, can be a double-edged sword.

If emissions drop quickly, limiting global warming, post-glacial uplift can act as a natural brake on ice-mass loss. It lifts the ice up, slowing the flow of ice from land to ocean. The study found this dynamic can reduce Antarctica’s contribution to sea- level rise by up to 40 per cent.

However, if carbon outputs keep pace and the planet heats up quickly, the rebounding land will not be enough to slow the rapidly melting ice, and instead pushes more ocean water away from Antarctica, accelerating sea-level rise along populated coastlines.

To reach their findings, Gomez and collaborating scholars from Canada and the United States developed a 3-D model of Earth’s interior. Their model used geophysical field measurements from the U.S. ANET-POLENET project, which had pioneered large-scale deployments of sensitive instruments to record the bedrock uplift and seismic signals across large expanses of Antarctica. These extensive field measurements were essential for characterizing the three-dimensional variations of the Antarctic mantle incorporated in the study.

“Our 3-D model peels back Earth’s layers like an onion, revealing dramatic variations in thickness and consistency of the mantle below. This knowledge helps us better predict how different areas will respond to melting,” said co-author Maryam Yousefi, a geodesist at Natural Resources Canada and previously a Postdoctoral Fellow at McGill and Penn State universities.

It’s the first model to capture the relationship between Antarctica’s ice and underlying earth in such detail, she added.

Notes Rob DeConto, a co-author and glaciologist at the University of Massachusetts, “This study marks a breakthrough in our ability to better predict the impacts of climate change on rising seas and to inform effective environmental policy.”

Global impacts

The findings, published in Science Advances, highlight the inequalities of climate change, the scholars noted. Island nations, which contribute the least to global emissions, are likely to bear the brunt of their consequences, they said.

The study is a collaboration between researchers at McGill, Pennsylvania State, Cambridge, Columbia, Colorado State, Ohio State, the University of Massachusetts Amherst, the University of Washington and the Union of Concerned Scientists. It was funded by the Canadian Natural Sciences and Engineering Research Council, the U.S. National Science Foundation and the Canada Research Chairs program.

Cats have a more acute sense of smell than humans, and the aroma of their food plays a big role in whether they’ll eat or snub what their owner serves for dinner. Feline palates are also more sensitive to umami (savory) flavors than humans, and they can’t taste sweetness. While meat-flavored food attractant sprays can help improve the scent and tastiness of dry kibble, the exact correlation between volatile flavor compounds and palatability is not well understood. Additionally, previous studies in this area lack input from a very important focus group: actual cats! So, Shiqing Song and colleagues relied on the expertise of a panel of 10 hungry adult cats to evaluate a series of food sprays containing different volatile flavor compounds.

To prepare their fragrant sprays, the researchers homogenized and heat-treated chicken livers. Then, they broke down proteins in the liver paste to various degrees using enzymes to produce four different food attractants. Song’s team identified over 50 different flavor compounds across the sprays, ranging from tropical and floral to sweaty and rubbery. For the taste test, the researchers coated commercially available cat food with chicken fat and then sprayed it with one of the four chicken liver attractants. The samples were presented to the cats alongside a control food treated with a different, commercially available attractant. The team observed which bowl the cats chose first and how much food they ate throughout the day.

The researchers found that most cats preferred and ate more of the foods sprayed with their attractants, particularly the sprays with proteins that were further broken-down by the enzymes and contained more free amino acids. These compounds are important flavor precursors that can undergo the Maillard reaction, which likely produced many different aroma-enhancing compounds during the heat treatment step. The favored foods contained more mushroom and fatty flavors as well, while the less-enjoyed foods featured acidic- and sweet-tasting compounds, possibly because fewer Maillard reactions occurred. This work could help inform future cat food formulations and increase your chances of choosing a kibble your finicky feline might enjoy.

The authors acknowledge funding from the Natural Science Foundation of Shanghai and thank their feline volunteers for their participation.

Respiratory viruses, typically causing mild illness, can have more serious consequences, as shown during the Covid-19 pandemic, including severe cases requiring hospitalization and the chronic sequelae of “long Covid.” These conditions often result in the destruction of large areas of the lungs, particularly the alveoli responsible for gas exchanges. Ineffective repair of these structures can lead to ARDS or a permanent reduction in the lungs’ ability to oxygenate blood, causing chronic fatigue and exercise intolerance.

While the role of macrophages during the acute phase of respiratory viral infections is well known, their function in the post-inflammatory period has been largely unexplored. A study by the GIGA Institute at the University of Liège reveals that atypical macrophages, characterized by specific markers and transiently recruited during the early recovery phase, play a beneficial role in regenerating pulmonary alveoli.

Led by Dr. Coraline Radermecker and Prof. Thomas Marichal from the Immunophysiology Laboratory, the study was conducted by Dr. Cecilia Ruscitti and benefited from the ULiège’s advanced technological platforms, including flow cytometry, fluorescence microscopy, and single-cell RNA sequencing. “Our findings provide a novel and crucial mechanism for alveolar repair by these atypical macrophages,” explains Coraline Radermecker. “We have detailed their characteristics, origin, location in the damaged lung, the signals they require to function, and their role in tissue regeneration, specifically acting on type 2 alveolar epithelial cells, the progenitors of alveolar cells.” The scientific community had overlooked these macrophages because they express a marker previously thought to be specific for another immune cell population, the neutrophils, and because they appear only briefly during the repair phase before disappearing.

“Our study highlights the reparative role of these macrophages, countering the prevailing idea that macrophages following respiratory viral infections are pathogenic,” adds Thomas Marichal. “By targeting the amplification of these macrophages or stimulating their repair functions, we could develop therapies to improve alveolar regeneration and reduce complications from serious respiratory infections and ARDS.”

To illustrate, consider the lungs as a garden damaged by a storm (viral infection). These newly discovered macrophages act like specialized gardeners who clear debris and plant new seeds, enabling the garden to regrow and regain its vitality.

This scientific breakthrough underscores the importance of research at the University of Liège and opens new avenues for treating respiratory diseases.

Now, scientists at MIT and the University of Chicago say they have identified the main process that formed the moon’s atmosphere and continues to sustain it today. In a study appearing in Science Advances, the team reports that the lunar atmosphere is primarily a product of “impact vaporization.”

In their study, the researchers analyzed samples of lunar soil collected by astronauts during NASA’s Apollo missions. Their analysis suggests that over the moon’s 4.5-billion-year history its surface has been continuously bombarded, first by massive meteorites, then more recently, by smaller, dust-sized “micrometeoroids.” These constant impacts have kicked up the lunar soil, vaporizing certain atoms on contact and lofting the particles into the air. Some atoms are ejected into space, while others remain suspended over the moon, forming a tenuous atmosphere that is constantly replenished as meteorites continue to pelt the surface.

The researchers found that impact vaporization is the main process by which the moon has generated and sustained its extremely thin atmosphere over billions of years.

“We give a definitive answer that meteorite impact vaporization is the dominant process that creates the lunar atmosphere,” says the study’s lead author, Nicole Nie, an assistant professor in MIT’s Department of Earth, Atmospheric, and Planetary Sciences. “The moon is close to 4.5 billion years old, and through that time the surface has been continuously bombarded by meteorites. We show that eventually, a thin atmosphere reaches a steady state because it’s being continuously replenished by small impacts all over the moon.”

Nie’s co-authors are Nicolas Dauphas, Zhe Zhang, and Timo Hopp at the University of Chicago, and Menelaos Sarantos at NASA Goddard Space Flight Center.

Weathering’s roles

In 2013, NASA sent an orbiter around the moon to do some detailed atmospheric reconnaissance. The Lunar Atmosphere and Dust Environment Explorer (LADEE, pronounced “laddie”) was tasked with remotely gathering information about the moon’s thin atmosphere, surface conditions, and any environmental influences on the lunar dust.

LADEE’s mission was designed to determine the origins of the moon’s atmosphere. Scientists hoped that the probe’s remote measurements of soil and atmospheric composition might correlate with certain space weathering processes that could then explain how the moon’s atmosphere came to be.

Researchers suspect that two space weathering processes play a role in shaping the lunar atmosphere: impact vaporization and “ion sputtering” — a phenomenon involving solar wind, which carries energetic charged particles from the sun through space. When these particles hit the moon’s surface, they can transfer their energy to the atoms in the soil and send those atoms sputtering and flying into the air.

“Based on LADEE’s data, it seemed both processes are playing a role,” Nie says. “For instance, it showed that during meteorite showers, you see more atoms in the atmosphere, meaning impacts have an effect. But it also showed that when the moon is shielded from the sun, such as during an eclipse, there are also changes in the atmosphere’s atoms, meaning the sun also has an impact. So, the results were not clear or quantitative.”

Answers in the soil

To more precisely pin down the lunar atmosphere’s origins, Nie looked to samples of lunar soil collected by astronauts throughout NASA’s Apollo missions. She and her colleagues at the University of Chicago acquired 10 samples of lunar soil, each measuring about 100 milligrams — a tiny amount that she estimates would fit into a single raindrop.

Nie sought to first isolate two elements from each sample: potassium and rubidium. Both elements are “volatile,” meaning that they are easily vaporized by impacts and ion sputtering. Each element exists in the form of several isotopes. An isotope is a variation of the same element, that consists of the same number of protons but a slightly different number of neutrons. For instance, potassium can exist as one of three isotopes, each one having one more neutron, and there being slightly heavier than the last. Similarly, there are two isotopes of rubidium.

The team reasoned that if the moon’s atmosphere consists of atoms that have been vaporized and suspended in the air, lighter isotopes of those atoms should be more easily lofted, while heavier isotopes would be more likely to settle back in the soil. Furthermore, scientists predict that impact vaporization, and ion sputtering, should result in very different isotopic proportions in the soil. The specific ratio of light to heavy isotopes that remain in the soil, for both potassium and rubidium, should then reveal the main process contributing to the lunar atmosphere’s origins.

With all that in mind, Nie analyzed the Apollo samples by first crushing the soils into a fine powder, then dissolving the powders in acids to purify and isolate solutions containing potassium and rubidium. She then passed these solutions through a mass spectrometer to measure the various isotopes of both potassium and rubidium in each sample.

In the end, the team found that the soils contained mostly heavy isotopes of both potassium and rubidium. The researchers were able to quantify the ratio of heavy to light isotopes of both potassium and rubidium, and by comparing both elements, they found that impact vaporization was most likely the dominant process by which atoms are vaporized and lofted to form the moon’s atmosphere.

“With impact vaporization, most of the atoms would stay in the lunar atmosphere, whereas with ion sputtering, a lot of atoms would be ejected into space,” Nie says. “From our study, we now can quantify the role of both processes, to say that the relative contribution of impact vaporization versus ion sputtering is about 70:30 or larger.” In other words, 70 percent or more of the moon’s atmosphere is a product of meteorite impacts, whereas the remaining 30 percent is a consequence of the solar wind.

“The discovery of such a subtle effect is remarkable, thanks to the innovative idea of combining potassium and rubidium isotope measurements along with careful, quantitative modeling,” says Justin Hu, a postdoc who studies lunar soils at Cambridge University, who was not involved in the study. “This discovery goes beyond understanding the moon’s history, as such processes could occur and might be more significant on other moons and asteroids, which are the focus of many planned return missions.”

“Without these Apollo samples, we would not be able to get precise data and measure quantitatively to understand things in more detail,” Nie says. “It’s important for us to bring samples back from the moon and other planetary bodies, so we can draw clearer pictures of the solar system’s formation and evolution.”

This work was supported, in part, by NASA and the National Science Foundation.

The research is published Aug. 2 in Science Advances.

The compound targets gram-positive bacteria, which can cause drug-resistant staph infections, toxic shock syndrome and other illnesses that can turn deadly. It was developed through a collaboration between the labs of Scott Hultgren, PhD, the Helen L. Stoever Professor of Molecular Microbiology, and Michael Caparon, PhD, a professor of molecular microbiology, and Fredrik Almqvist, a professor of chemistry at the University of Umeå in Sweden.

A new type of antimicrobial would be good news for clinicians seeking effective treatments against pathogens that are becoming more resistant to currently available drugs, and thus much more dangerous.

“All of the gram-positive bacteria that we’ve tested have been susceptible to that compound. That includes enterococci, staphylococci, streptococci, C. difficile, which are the major pathogenic bacteria types,” said Caparon, the co-senior author. “The compounds have broad-spectrum activity against numerous bacteria.”

It’s based on a type of molecule called ring-fused 2-pyridone. Initially, Caparon and Hultgren had asked Almqvist to develop a compound that might prevent bacterial films from attaching to the surface of urethral catheters, a common cause of hospital-associated urinary tract infections. Discovering that the resulting compound had infection-fighting properties against multiple types of bacteria was a happy accident.

The team named their new family of compounds GmPcides (for gram-positive-icide). In past work, the authors showed that GmPcides can wipe out bacteria strains in petri dish experiments. In this latest study, they decided to test it on necrotizing soft-tissue infections, which are fast-spreading infections usually involving multiple types of gram-positive bacteria, for which Caparon already had a working mouse model. The best known of these, necrotizing fasciitis or “flesh-eating disease,” can quickly damage tissue severely enough to require limb amputation to control its spread. About 20% of patients with flesh-eating disease die.

This study focused on one pathogen, Streptococcus pyogenes, which is responsible for 500,000 deaths every year globally, including flesh-eating disease. Mice infected with S. pyogenes and treated with a GmPcide fared better than did untreated animals in almost every metric. They had less weight loss, the ulcers characteristic of the infection were smaller, and they fought off the infection faster.

The compound appeared to reduce the virulence of the bacteria and, remarkably, speed up post-infection healing of the damaged areas of the skin.

It is not clear how GmPcides accomplish all of this, but microscopic examination revealed that the treatment appears to have a significant effect on bacterial cell membranes, which are the outer wrapping of the microbes.

“One of the jobs of a membrane is to exclude material from the outside,” Caparon said. “We know that within five to ten minutes of treatment with GmPcide, the membranes start to become permeable and allow things that normally should be excluded to enter into the bacteria, which suggests that those membranes have been damaged.”

This can disrupt the bacteria’s own functions, including those that cause damage to their host, and make the bacteria less effective at combating the host’s immune response to infections.

In addition to their antibacterial effectiveness, GmPcides appear to be less likely to lead to drug-resistant strains. Experiments designed to create resistant bacteria found very few cells able to withstand treatment and thus pass on their advantages to the next generation of bacteria.

Caparon explained that there is a long way to go before GmPcides are likely to find their way into local pharmacies. Caparon, Hultgren and Almqvist have patented the compound used in the study and licensed it to a company, QureTech Bio, in which they have an ownership stake, with the expectation that they will be able to collaborate with a company that has the capacity to manage the pharmaceutical development and clinical trials to potentially bring GmPcides to market.

Hultgren said that the kind of collaborative science that created GmPcides is what is needed to treat intractable problems like antimicrobial resistance.

“Bacterial infections of every type are an important health problem, and they are increasingly becoming multi-drug resistant and thus harder to treat,” he said. “Interdisciplinary science facilitates the integration of different fields of study that can lead to synergistic new ideas that have the potential to help patients.”