“Looking at recent, natural climate anomalies helps to understand the processes and mechanisms that human-induced global warming may trigger,” says Dr Anastasia Zhuravleva, lead author of the study. She was a PhD student at GEOMAR and received the Annette Barthelt Prize for her dissertation in 2019. She then worked as a post-doctoral researcher at GEOMAR and Dalhousie University, where the study was completed.

“Researchers often consider an increase in sea ice extent and desalination in the subpolar North Atlantic as possible triggers for past cold periods, but processes in the tropical Atlantic appear to be equally important,” says Dr Zhuravleva. “In fact, in contrast to the northern and mid-latitudes, there is little information on these recent climate events from the subtropical-tropical Atlantic and their impact on regions in the Northern Hemisphere,” adds Dr Henning Bauch, paleoclimatologist at AWI and GEOMAR, co-initiator and co-author of the study. “This is where our research comes in.”

So, what happened in the tropical Atlantic during historical climate anomalies, and how might potential changes there have affected ocean circulation and climate much further north? To answer these questions, the team worked on a sediment profile from the southern Caribbean and reconstructed the salinity and temperature of the surface water over the last 1700 years. Among other things, the researchers determined the isotopic and elemental composition of the calcareous shells of plankton.

The results show a cooling of about 1°C during the Little Ice Age. “It is a significant temperature change for this region,” says Dr Mahyar Mohtadi, co-author of the study and head of the Low Latitude Climate Variability group at MARUM. “Particularly noteworthy is the occurrence of another pronounced cooling for the 8th-9th centuries. Colder temperatures in the otherwise warm tropical ocean led to lower regional rainfall, which coincided with severe droughts in the Yucatan Peninsula and the decline of the Classic Maya culture.”

In addition, the researchers found that the cold climate anomalies in the subpolar North Atlantic and Europe were accompanied by weaker ocean circulation and increased salinity in the Caribbean. “Advection, or the movement of tropical salt to high northern latitudes, is essential for maintaining high surface densities in the subpolar North Atlantic. This is a prerequisite for the overall stability of the large-scale ocean circulation, including the transfer of warm Gulf Stream water, which is responsible for our mild temperatures in Europe,” says Dr Bauch.

The data on the historical past thus allow a reconstruction of the connection across the North Atlantic. Initial cooling can be caused by volcanic eruptions, low solar activity and feedbacks between sea ice and the ocean in the north. The new study provides evidence that a decrease in salt movement to high northern latitudes will amplify and prolong these climate events. Conversely, the slow movement of positive salinity anomalies from the tropics will eventually increase the density at the surface of the subpolar North Atlantic. This may favour the northward transport of heat by ocean currents, resulting in milder temperatures over Europe and North America.

“Such a salinity feedback is known from models and has been assumed for the Little Ice Age. However, in the absence of tropical ocean data, these assumptions have been based on less direct precipitation records,” says Dr Zhuravleva.

There is evidence that the Gulf Stream is weakening and that human-induced warming is a likely cause. What is certain is that the consequences of this change will be global. The extent to which the different climate mechanisms interact has been an open question. This study now confirms that the south-north transport of salt is a key factor in the processes involved.

Now, a new Harvard Medical School study published Nov. 3 in Science Immunology may offer a molecular explanation behind this century-old observation.

The study, done in mice, suggests that the beneficial effects of exercise may be driven, at least partly, by the immune system. It shows that muscle inflammation caused by exertion mobilizes inflammation-countering T cells, or Tregs, which enhance the muscles’ ability to use energy as fuel and improve overall exercise endurance.

Long known for their role in countering the aberrant inflammation linked to autoimmune diseases, Tregs now also emerge as key players in the body’s immune responses during exercise, the research team said.

“The immune system, and the T cell arm in particular, has a broad impact on tissue health that goes beyond protection against pathogens and controlling cancer. Our study demonstrates that the immune system exerts powerful effects inside the muscle during exercise,” said study senior investigator Diane Mathis, Morton Grove-Rasmussen Professor of Immunology in the Blavatnik Institute at HMS.

Mice are not people, and the findings remain to be replicated in further studies, the researchers cautioned. However, the study is an important step toward detailing the cellular and molecular changes that occur during exercise and confer health benefits.

Understanding the molecular underpinnings of exercise

Protecting from cardiovascular disease, reducing the risk of diabetes, shielding against dementia. The salutary effects of exercise are well established. But exactly how does exercise make us healthy? The question has intrigued researchers for a long time.

The new findings come amid intensifying efforts to understand the molecular underpinnings of exercises. Untangling the immune system’s involvement in this process is but one aspect of these research efforts.

“We’ve known for a long time that physical exertion causes inflammation, but we don’t fully understand the immune processes involved,” said study first author Kent Langston, a postdoctoral researcher in the Mathis lab. “Our study shows, at very high resolution, what T cells do at the site where exercise occurs, in the muscle.”

Most previous research on exercise physiology has focused on the role of various hormones released during exercise and their effects on different organs such as the heart and the lungs. The new study unravels the immunological cascade that unfolds inside the actual site of exertion — the muscle.

T cell heroes and inflammation-fueling villains

Exercise is known to cause temporary damage to the muscles, unleashing a cascade of inflammatory responses. It boosts the expression of genes that regulate muscle structure, metabolism, and the activity of mitochondria, the tiny powerhouses that fuel cell function. Mitochondria play a key role in exercise adaptation by helping cells meet the greater energy demand of exercise.

In the new study, the team analyzed what happens in cells taken from the hind-leg muscles of mice that ran on a treadmill once and animals that ran regularly. Then, the researchers compared them with muscle cells obtained from sedentary mice.

The muscle cells of the mice that ran on treadmills, whether once or regularly, showed classic signs of inflammation — greater activity in genes that regulate various metabolic processes and higher levels of chemicals that promote inflammation, including interferon.

Both groups had elevated levels of Treg cells in their muscles. Further analyses showed that in both groups, Tregs lowered exercise-induced inflammation. None of those changes were seen in the muscle cells of sedentary mice.

However, the metabolic and performance benefits of exercise were apparent only in the regular exercisers — the mice that had repeated bouts of running. In that group, Tregs not only subdued exertion-induced inflammation and muscle damage, but also altered muscle metabolism and muscle performance, the experiments showed. This finding aligns with well-established observations in humans that a single bout of exercise does not lead to significant improvements in performance and that regular activity over time is needed to yield benefits.

Further analyses confirmed that Tregs were, indeed, responsible for the broader benefits seen in regular exercisers. Animals that lacked Tregs had unrestrained muscle inflammation, marked by the rapid accumulation of inflammation-promoting cells in their hindleg muscles. Their muscle cells also had strikingly swollen mitochondria, a sign of metabolic abnormality.

More importantly, animals lacking Tregs did not adapt to increasing demands of exercise over time the way mice with intact Tregs did. They did not derive the same whole-body benefits from exercise and had diminished aerobic fitness.

These animals’ muscles also had excessive amounts of interferon, a known driver of inflammation. Further analyses revealed that interferon acts directly on muscle fibers to alter mitochondrial function and limit energy production. Blocking interferon prevented metabolic abnormalities and improved aerobic fitness in mice lacking Tregs.

“The villain here is interferon,” Langston said. “In the absence of guardian Tregs to counter it, interferon went on to cause uncontrolled damage.”

Interferon is known to promote chronic inflammation, a process that underlies many chronic diseases and age-related conditions and has become a tantalizing target for therapies aimed at reducing inflammation. Tregs have also captured the attention of scientists and industry as treatments for a range of immunologic conditions marked by abnormal inflammation.

The study findings provide a glimpse into the cellular innerworkings behind exercise’s anti-inflammatory effects and underscore its importance in harnessing the body’s own immune defenses, the researchers said.

There are efforts afoot to design interventions targeting Tregs in the context of specific immune-mediated diseases. And while immunologic conditions driven by aberrant inflammation require carefully calibrated therapies, exercise is yet another way to counter inflammation, the researchers said.

“Our research suggests that with exercise, we have a natural way to boost the body’s immune responses to reduce inflammation,” Mathis said. “We’ve only looked in the muscle, but it’s possible that exercise is boosting Treg activity elsewhere in the body as well.”

Inspired by the enhanced visual system of the Papilio xuthus butterfly, a team of researchers have developed an imaging sensor capable of “seeing” into the UV range inaccessible to human eyes. The design of the sensor uses stacked photodiodes and perovskite nanocrystals (PNCs) capable of imaging different wavelengths in the UV range. Using the spectral signatures of biomedical markers, such as amino acids, this new imaging technology is even capable of differentiating between cancer cells and normal cells with 99% confidence.

This new research, led by University of Illinois Urbana-Champaign electrical and computer engineering professor Viktor Gruev and bioengineering professor Shuming Nie, was recently published in the journal Science Advances.

Small Variations

“We’ve taken inspiration from the visual system of butterflies, who are able to perceive multiple regions in the UV spectrum, and designed a camera that replicates that functionality,” Gruev says. “We did this by using novel perovskite nanocrystals, combined with silicon imaging technology, and this new camera technology can detect multiple UV regions.”

UV light is electromagnetic radiation with wavelengths shorter than that of visible light (but longer than x-rays). We are most familiar with UV radiation from the sun and the dangers it poses to human health. UV light is categorized into three different regions — UVA, UVB and UVC — based on different wavelength ranges. Because humans cannot see UV light, it is challenging to capture UV information, especially discerning the small differences between each region.

Butterflies, however, can see these small variations in the UV spectrum, like humans can see shades of blue and green. Gruev notes, “It is intriguing to me how they are able to see those small variations. UV light is incredibly difficult to capture, it just gets absorbed by everything, and butterflies have managed to do it extremely well.”

The Imitation Game

Humans have trichromatic vision with three photoreceptors, where every color perceived can be made from a combination of red, green and blue. Butterflies, however, have compound eyes, with six (or more) photoreceptor classes with distinct spectral sensitivities. In particular, the Papilio xuthus, a yellow, Asian swallowtail butterfly, has not only blue, green and red, but also violet, ultraviolet and broadband receptors. Further, butterflies have fluorescent pigments that allow them to convert UV light into visible light which can then be easily sensed by their photoreceptors. This allows them to perceive a broader range of colors and details in their environment.

Beyond the increased number of photoreceptors, butterflies also exhibit a unique tiered structure in their photoreceptors. To replicate the UV sensing mechanism of the Papilio xuthus butterfly, the UIUC team has emulated the process by combining a thin layer of PNCs with a tiered array of silicon photodiodes.

PNCs are a class of semiconductor nanocrystals that display unique properties similar to that of quantum dots — changing the size and composition of the particle changes the absorption and emission properties of the material. In the last few years, PNCs have emerged as an interesting material for different sensing applications, such as solar cells and LEDs. PNCs are extremely good at detecting UV (and even lower) wavelengths that traditional silicon detectors are not. In the new imaging sensor, the PNC layer is able to absorb UV photons and re-emit light in the visible (green) spectrum which is then detected by the tiered silicon photodiodes. Processing of these signals allows for mapping and identification of UV signatures.

Healthcare and Beyond

There are various biomedical markers present in cancerous tissues at higher concentrations than in healthy tissues — amino acids (building blocks of proteins), proteins, and enzymes. When excited with UV light, these markers light up and fluoresce in the UV and part of the visible spectrum, in a process called autofluorescence. “Imaging in the UV region has been limited and I would say that has been the biggest roadblock for making scientific progress,” explains Nie. “Now we have come up with this technology where we can image UV light with high sensitivity and can also distinguish small wavelength differences.”

Because cancer and healthy cells have different concentrations of markers and therefore different spectral signatures, the two classes of cells can be differentiated based on their fluorescence in the UV spectrum. The team evaluated their imaging device on its ability to discriminate cancer-related markers and found that is capable of differentiating between cancer and healthy cells with 99% confidence.

Gruev, Nie and their collaborative research team envision being able to use this sensor during surgery. One of the biggest challenges is knowing how much tissue to remove to ensure clear margins and such a sensor can help facilitate the decision-making process when a surgeon is removing a cancerous tumor.

“This new imaging technology is enabling us to differentiate cancerous versus healthy cells and is opening up new and exciting applications beyond just health,” Nie says. There are many other species besides butterflies capable of seeing in the UV, and having a way to detect that light will provide interesting opportunities for biologists to learn more about these species, such as their hunting and mating habits. Bringing the sensor underwater can help bring a greater understanding of that environment as well. While a lot of UV is absorbed by water, there is still enough that makes it through to have an impact and there are many animals underwater that also see and use UV light.

Networked intelligent devices and sensors can improve the energy efficiency of consumer products and buildings by monitoring their consumption in real time. Miniature devices like these being developed under the concept of the Internet of Things require energy sources that are as compact as possible in order to function autonomously. Monolithically integrated batteries that simultaneously generate, convert, and store energy in a single system could be used for this purpose.

A team of scientists at the University of Freiburg’s Cluster of Excellence Living, Adaptive, and Energy-Autonomous Materials Systems (livMatS) has developed a monolithically integrated photo battery consisting of an organic polymer-based battery and a multi-junction organic solar cell. The battery, presented by Rodrigo Delgado Andrés andDr. Uli Würfel, University Freiburg, and Robin Wessling and Prof. Dr. Birgit Esser, University of Ulm, is the first monolithically integrated photo battery made of organic materials to achieve a discharge potential of 3.6 volts. It is thus among the first systems of this kind capable of powering miniature devices. The team published their results in the journal Energy & Environmental Science.

Combination of a multi-junction solar cell and a dual-ion battery

The researchers developed a scalable method for the photo battery which allows them to manufacture organic solar cells out of five active layers. “The system achieves relatively high voltages of 4.2 volts with this solar cell,” explains Wessling. The team combined this multi-junction solar cell with a so-called dual-ion battery, which is capable of being charged at high currents, unlike the cathodes of conventional lithium batteries. With careful control of illumination intensity and discharge rates, a photo battery constructed in this way is capable of rapid charging in less than 15 minutes at discharge capacities of up to 22 milliampere hours per gram (mAh g^-1). In combination with the averaged discharge potential of 3.6 volts, the devices can provide an energy density of 69 milliwatt hours per gram (mWh g^-1) and a power density of 95 milliwatts per gram (mW g^-1). “Our system thus lays the foundation for more in-depth research and further developments in the area of organic photo batteries,” says Wessling.

A recent theme in material physics research has been the use of intense laser light to modify the properties of magnetic materials. By carefully engineering the laser light’s properties, researchers have been able to drastically modify the electrical conductivity and optical properties of different materials. However, this requires continuous stimulation by high-intensity lasers and is associated with some practical problems, mainly that it is difficult to stop the material from heating up. Researchers are therefore looking for ways to gain similar control over materials using light, but without employing intense lasers.

Now theoreticians at the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) in Hamburg, Germany, Stanford University and the University of Pennsylvania (both in the USA) have come up with a fundamentally different approach to change a real material’s magnetic properties in a cavity — without the use of any laser light. Their collaboration shows that the cavity alone is enough to turn the zigzag antiferromagnet α-RuCl₃ into a ferromagnet.

Crucially, the team demonstrates that even in an apparently dark cavity, α-RuCl₃ senses modifications of the electromagnetic environment and changes its magnetic state accordingly. This is a purely quantum mechanical effect, arising from the fact that within quantum theory the empty cavity (technically called the vacuum state) is never really empty. Instead, the light field fluctuates so that light particles pop in and out of existence which, in turn, affects the properties of the material.

“The optical cavity confines the electromagnetic field to a very small volume, thereby enhancing the effective coupling between the light and the material,” explains lead author Emil Viñas Boström, a postdoctoral researcher in the MPSD Theory Group. “Our results show that carefully engineering the vacuum fluctuations of the cavity electric field can lead to drastic changes in a material’s magnetic properties.” As no light excitation is needed, the approach in principle circumvents the problems associated with continuous laser driving.

This is the first work demonstrating such cavity control over magnetism in a real material, and follows previous investigations into cavity control of ferroelectric and superconducting materials. The researchers hope that designing specific cavities will help them realize new and elusive phases of matter, and to better understand the delicate interplay between light and matter.

These preparative mass spectrometers can be used to produce chemical compounds in a new way. The researchers recently synthesised a new compound from a charged molecular fragment and nitrogen from the air, which has a wide range of potential applications in building new molecular structures. They have published their new findings in the journal Angewandte Chemie. The journal cover visualizes the concept of “harvesting” molecules that were composed from fragments in a seed box-like approach in the gas phase of a mass spectrometer directly into a chemical flask that would typically be employed for conventional synthesis.

Developing new ways to break and reform chemical bonds is one of the main tasks of basic chemical research. “When a bond in a charged molecule is broken, the result is often a chemically ‘aggressive’ fragment, which we call a reactive fragment. These fragments are difficult to control using established methods of chemical synthesis. You can think of them as untamed beasts that attack anything in their path. In a mass spectrometer, there are many ways to break certain bonds and generate fragments,” says Dr Warneke, describing the processes in mass spectrometers. According to him, the “beasts” are kept under special conditions because there is a vacuum inside the mass spectrometer. This means that there is nothing for them to attack, thus preventing uncontrolled chemical reactions. “If we then offer a certain molecule, for example nitrogen, which is normally unreactive and doesn’t bind, the beast is satisfied with it because it has no other choice,” he says. In this way, molecules that are very difficult to bind, such as nitrogen, can be easily incorporated into a new substance,” Warneke continues.

In the past, the research team has used this approach to bring reactive fragments into very unusual reactions, for example, with noble gases, which are the most difficult of all chemical elements to bind. “The basic strategy of controlling chemical beasts in mass spectrometers is not new,” says Warneke. It has been used for decades to analyse the properties of reactive fragments. However, the new compounds found in this way could not be further used. Mass spectrometers show what is happening inside them, but the new substances are only produced in tiny quantities and cannot usually be extracted. They are often simply destroyed when the signal used for analyses is generated.

This is why researchers usually come away from experiments with mass spectrometers with “great knowledge” but “empty hands.” “They have the beast under control. Exactly what they were hoping for happens, they observe the new molecule with potentially fascinating properties, and then it’s gone,” says Warneke, describing chemical experiments in conventional mass spectrometers. The new publication could fundamentally change this view of chemical reactions in mass spectrometers. The research team produced a new substance from an aggressive fragment and unreactive nitrogen and collected it with preparative mass spectrometers in sufficient quantities so that it could be seen with the naked eye, handled and further experimented with.

The amount of substance produced by this method will remain limited to thin film technology applications for some time to come. However, preparative mass spectrometry could soon open up completely new possibilities for these applications, for example, in the production of microchips, solar cells or biologically active coatings. The junior research group has now reached an important milestone in its project, which has been funded by the Volkswagen Foundation’s Freigeist Fellowship since 2020.

The scientists from The Ohio State University have reported in the Journal of Medical Entomology on the state’s first known established population of Asian longhorned ticks, and are now conducting research focused on monitoring and managing these pests.

So far, these ticks are not deemed to be a threat to human health. They tend to favor large livestock and wildlife, such as cattle and deer. Just a handful of the hundred ticks from the farm screened for infectious agents tested positive for pathogens, including one, Anaplasma phagocytophilium, that can cause disease in animals and humans. Elsewhere this tick carries another pathogen, Theileria orientalis, that affects cattle, and cases of bovine theileriosis have been reported in Ohio.

Researchers say the tiny brown ticks — the size of a sesame seed in some life stages and pea-sized when engorged — are persistent, however: Surveillance showed they returned the following summer to the farm despite the application of pesticides in 2021.

“They are going to spread to pretty much every part of Ohio and they are going to be a long-term management problem. There is no getting rid of them,” said Risa Pesapane, senior author of the paper and an assistant professor of veterinary preventive medicine at Ohio State.

“The good news about the ticks, though, is that most tick control agents that we currently have seem to kill them. Still, managing them is not easy because of how numerous they are and how easily they can come back.”

Asian longhorned ticks originate from East Asia and were first detected in the United States in New Jersey in 2017. When Pesapane joined Ohio State in 2019 as a tick-borne disease ecologist, the ticks were reported in West Virginia — meaning it was only a matter of time before they crossed the river into Ohio, she said.

She found the first of these ticks in Ohio, on a stray dog in Gallia County in 2020, and another was collected from a cow in Jackson County in June 2021. And then a farmer from Monroe County called Ohio State later that summer to report three of his 18 cattle, heavily infested with ticks, had died.

“One of those was a healthy male bull, about 5 years old. Enormous. To have been taken down by exsanguination by ticks, you can imagine that was tens of thousands of ticks on one animal,” said Pesapane, who also has a faculty appointment in Ohio State’s School of Environment and Natural Resources.

Pesapane and colleagues collected almost 10,000 ticks within about 90 minutes on the farm, leading her to speculate that there were more than 1 million of them in the roughly 25-acre pasture.

Asian longhorned ticks’ secret colonization weapon is the ability to reproduce asexually, with each female laying up to 2,000 eggs at a time — and all 2,000 of those female offspring able to do the same.

“There are no other ticks in North America that do that. So they can just march on, with exponential growth, without any limitation of having to find a mate,” Pesapane said. “Where the habitat is ideal, and anecdotally it seems that unmowed pastures are an ideal location, there’s little stopping them from generating these huge numbers.”

Because of their ability to hide in vegetation, Asian longhorned ticks also can escape pesticides that kill only when coming into direct contact with a pest.

“It would be wisest to target them early in the season when adults become active, before they lay eggs, because then you would limit how many will hatch and reproduce in subsequent years. But for a variety of reasons, I tell people you cannot spray your way out of an Asian longhorned tick infestation — it will require an integrated approach,” Pesapane said.

She and colleagues are working as rapidly as they can at filling in knowledge gaps about these invaders and developing training materials and policy recommendations for affected industries. As one example, Pesapane said, tick inspections of livestock could provide a window for application of an antiparasitic agent to eliminate the risk of transporting the exotic arachnids across multiple state lines.

Ohioans are encouraged to help with research efforts: People who think they’ve spotted an Asian longhorned tick can email ticks@osu.edu for instructions on how to collect the specimen and send it to Ohio State scientists as part of ongoing surveillance. To date, the lab has received Asian longhorned ticks from residents of 11 Ohio counties.

More information about spotting Asian longhorned ticks and preventing tick exposure is available on Ohio State’s Bite Site.

This work was supported by the U.S. Department of Agriculture. Co-authors on the study were Andreas Eleftheriou, Julia Beckett and Ningzhu Bai, all of Ohio State.

Maintaining species-rich and resilient ecosystems is key to preserving biodiversity and mitigating climate change. Here, megafauna — the part of the animal population in an area that is made up of the largest animals — plays an important role. In a new study published in the scientific journal One Earth, an international research team, of which Lund University is a part, has investigated the intricate interplay between the number of voracious herbivores and the diversity of trees in the world’s protected areas.

“Our findings reveal a fascinating and complex story of how large herbivorous animals shape the world’s natural landscapes. The tree cover in these areas is sparser, but the diversity of the tree cover is much higher than in areas without large herbivores,” says Lanhui Wang, a researcher in physical geography and ecosystem science at Lund University.

“In our global analysis, we find a substantial association between the biomass of large herbivores and varied tree cover in protected areas, notably for browsers and mixed-feeders such as elephants, bison and moose and in non-extreme climates,” explains the study’s senior author, Jens-Christian Svenning, professor at Aarhus University.

Hereby, the study supports that large wild herbivores promote a diverse vegetation structure, creating a rich habitat for many other species. This is due to the animals’ consumption of vegetation as well as physical disturbances.

According to Lanhui Wang, these new research findings highlight the need to integrate large herbivores into restoration and conservation strategies. Not only for the sake of the animals themselves but also for the vital role they play in shaping landscapes and influencing biodiversity. The researchers argue that this aspect is not sufficiently considered within the framework of sustainable land management and ecosystem restoration.

“At a time when global initiatives are intensely focused on combating climate change and biodiversity loss, our findings highlight the need for a broader and more nuanced discussion about ecosystem management and conservation measures. It is of utmost importance to integrate understanding of the ecological impact of megafauna into this,” says Lanhui Wang.

The UN has declared the 2020s as the decade of ecosystem restoration. In total, 115 countries have agreed to restore up to 100,000 square kilometres of nature in total. To achieve this, more wild-living large herbivores are needed worldwide, says Lanhui Wang.

“I believe that we will need to protect and conserve large herbivores to achieve the UN goals. Megafauna are crucial for tree cover, which in turn promotes carbon sequestration and a diversity of habitats,” says Lanhui Wang.