Cytotoxic T lymphocytes serve as the immune system’s specialized “killer” cells, targeting and eliminating infected or cancerous cells with remarkable accuracy. Their effectiveness depends on a tightly controlled contact point known as the “immune synapse,” where they release toxic molecules that destroy the target while leaving nearby healthy cells unharmed. Until recently, scientists could not clearly observe how these structures are organized.

Researchers at the University of Geneva (UNIGE) and the Lausanne University Hospital (CHUV) have now visualized these processes in three dimensions while preserving conditions close to their natural state. Their findings, published in Cell Reports, show how the internal organization of cytotoxic T cells supports their function and point to new possibilities in immuno-oncology.

How Killer T Cells Precisely Eliminate Threats
When the body encounters infection or cancer, cytotoxic T lymphocytes attach to the affected cell and form the immune synapse. Through this interface, they release toxic compounds that trigger the death of the target cell. This highly controlled process allows the immune system to remove harmful cells without damaging surrounding tissue.

Although the overall mechanism is well known, studying its fine structure at the nanometer scale inside intact human cells has been difficult. One major challenge comes from sample preparation, which can distort delicate cellular features. Traditional imaging methods often require compromises between resolution, the size of the area observed, and the preservation of natural structures.

Cornell University scientists have made significant progress toward what many consider the holy grail of male birth control: a safe, long-acting, fully effective, and nonhormonal contraceptive that can be reversed.

Stopping Sperm Production by Targeting Meiosis
In a proof-of-principle study conducted in mice over six years, researchers showed that interrupting a natural checkpoint in meiosis, the process responsible for producing sex cells, can temporarily halt sperm production. Importantly, this approach worked without causing permanent damage.

To achieve this, the team used JQ1, a small molecule inhibitor originally developed as a research tool for studying cancer and inflammatory diseases. Although JQ1 is not suitable as a treatment due to neurological side effects, it is known to interfere with a specific stage of meiosis called prophase 1. This allowed the researchers to demonstrate for the first time that sperm production can be safely and reversibly stopped by targeting meiosis and sperm production at this stage.

“We’re practically the only group that’s pushing the idea that contraception targets in the testis are a feasible way to stop sperm production,” said Paula Cohen, professor of genetics and director of the Cornell Reproductive Sciences Center.

“Our study shows that mostly we recover normal meiosis and complete sperm function, and more importantly, that the offspring are completely normal,” Cohen said.

Seasonal models are predicting an El Niño climate pattern that could be the strongest on record, bringing with it more extreme weather.

"I think we're going to see weather events that we've never seen in modern history before," WFLA-TV Chief Meteorologist and Climate Specialist Jeff Berardelli, in Tampa, Florida, said Friday.

An El Niño event is expected to develop from the middle of this year, impacting global temperature and rainfall patterns, according to the World Meteorological Organization. While the models indicate that this may be a strong event, the WMO cautioned that the models also have a harder time making accurate forecasts in the spring.

What El Niño is
El Niño is a cyclical and natural warming of patches of the equatorial Pacific that then alters the world's weather patterns. Its counterpart, La Niña, is marked by waters that are cooler than average.

Berardelli said an El Niño event essentially redistributes heat on Earth. Currently, the subsurface heat in the Pacific is moving east across the ocean and ascending to the surface from the deep waters, the initial stages of El Niño.

The WMO's Global Seasonal Climate Update showed that sea-surface temperatures are rising rapidly. There is high confidence in the onset of El Niño, followed by further intensification in the months to follow, according to Wilfran Moufouma Okia, chief of climate prediction at WMO.

El Niño typically occurs every two to seven years and lasts around nine to 12 months, WMO said.

🕷️ Scientists are rethinking what venomous really means and the results are surprising. 🤔

Find out how expanding the scientific definition of venom is dramatically increasing the number of species we consider as venomous.

For the first time, scientists have measured the instantaneous mind-blowing power of jets blasting from a black hole.

The jet power from this relatively close black hole-star system is equivalent to 10,000 suns, an international research team reported Thursday. They also tracked the jet speed: roughly 355 million mph (540 million kph)—half the speed of light.

Located 7,200 light-years away, Cygnus X-1 features not only a black hole—the first one ever identified more than a half-century ago—but a blue supergiant star, its constant companion. A light-year is nearly 6 trillion miles (9.7 trillion kilometers).

The University of Oxford's Steve Prabu and his team based their findings on 18 years of high-resolution radio imaging obtained by a global telescope network. He conducted the research while still at Australia's Curtin University, which led the study published in Nature Astronomy.

Prabu and his colleagues were able to measure the swift power of these "dancing jets" as he calls them, as they were pushed in opposite directions by the star's wind. The group based its calculations on how much the jets were bent by the stellar wind as well as computer modeling.

The human brain is constantly managing streams of information that move at very different speeds. Some signals require immediate responses to sudden changes in the environment, while others involve slower forms of thinking, such as interpreting meaning, context, or complex situations.

A new study from Rutgers Health, published in Nature Communications, examined how the brain combines these fast and slow forms of processing through its network of white matter connections. Researchers say this coordination is essential for cognition, behavior, and the ability to respond effectively to the world around us.

Different parts of the brain are tuned to process information over specific time ranges. Scientists refer to these patterns as intrinsic neural timescales, or INTs.

“To affect our environment through action, our brains must combine information processed over different timescales,” said Linden Parkes, assistant professor of Psychiatry at Rutgers Health and the senior author of the study. “The brain achieves this by leveraging its white matter connectivity to share information across regions, and this integration is crucial for human behavior.”

Mapping the Brain’s Communication Networks
To explore how this system works, Parkes and his colleagues analyzed multimodal brain imaging data from 960 people. The team created detailed maps of each participant’s brain connections, known as connectomes, and used mathematical models designed to track how complex systems evolve over time. This allowed the researchers to study how information travels through the brain’s communication pathways.

“Our work probes the mechanisms underlying this process in humans by directly modeling regions’ INTs from their connectivity,” said Parkes, a core member of the Rutgers Brain Health Institute and the Center for Advanced Human Brain Imaging Research. “This draws a direct link between how brain regions process information locally and how that processing is shared across the brain to produce behavior.”

Back when dinosaurs stomped the Earth, dinky mammals scurried about in their shadows. The little furballs, hiding out in underground burrows, provided a fresh niche for a novel reptile: the snake. Skinny snakes could squeeze into the homes of mammals and gobble them up.

At least, that's how the dawn of snakes is imagined by Marc Tollis, an evolutionary biologist at Northern Arizona University in Flagstaff. No one knows for sure. Like the creatures themselves, the snake fossil record is long and thin, leaving gaps in snaky history. Major questions, such as where they got their start and who their closest relatives are, remain unanswered.

Today, new fossils and modern techniques are updating the story of snakes. Starting about 125 million years ago, snakes used their flexible body plans to diversify like crazy, conquering regions that now make up six continents, plus the Indian and Pacific Oceans — and Tollis would not be surprised to find snake fossils in once-balmy Antarctica, either.

Microplastics are absorbing heat in the atmosphere and contributing to global warming, a new study reveals.

Microplastics are infamous for being everywhere, contaminating ecosystems and accumulating inside our bodies. Scientists have known for a while that plastics are also blown high into the atmosphere, where they are now pervasive, but it was unclear what impact they might be having up there.

Now, the new study, published Monday (May 4) in the journal Nature Climate Change, has found that overall, plastic particles create a warming effect. This is because, while very-light-colored plastics scatter sunlight back into space, darker-colored plastics absorb sunlight and radiation.

Study co-author Drew Shindell, a distinguished professor of Earth science at Duke University, told Live Science that the climate change impact of plastic particles is fairly small  —  comparable to the emissions of a small country. In numbers, this is the equivalent of around a couple of percent of the contribution from carbon dioxide (CO2) — the main driver of climate change — or a couple hundredths of a degree of warming. However, the researchers' modeling was based on a limited understanding of the amount of plastic in the atmosphere, so the extent of the warming effect is uncertain.

"The key finding is really that the warming strongly outweighs the cooling," Shindell said. "I think we have a lot of confidence in that because we did all of these measurements in the laboratory of how [microplastics and nanoplastics] interact with sunlight. What we don't have so much confidence in and what's still a big uncertainty is exactly how many of these are in the atmosphere."

The growing popularity of electronic devices—from fitness trackers and laptops to smartphones—is driving demand for more energy-efficient computing chips. Now, researchers have found a way to change the electronic properties of a common semiconductor material, potentially laying the foundation for faster, lower-power data storage and processing.

Transforming a common chip material
In a study published in Science, a UC Berkeley-led team of researchers discovered they can transform titanium dioxide (TiO₂) into a ferroelectric material by reducing its thickness to less than 3 nanometers (nm), roughly the diameter of a single strand of human DNA. These findings, according to the researchers, could open a pathway toward ultra-scaled, energy-efficient electronic devices.

Ferroelectric materials, with their ability to switch electric polarizations, have a long history in the semiconductor industry. Today, many researchers believe that they may hold the key to enabling next-generation, energy-efficient nanoelectronics, including non-volatile memory, logic devices and emerging computing technologies.

Antimicrobial resistance is creating growing challenges for both healthcare and food production, increasing the need for affordable new materials that can fight dangerous pathogens.

A multidisciplinary team led by Flinders University, working with researchers from the UK, has developed a new material designed for safe and effective antimicrobial and antifungal use.

The World Health Organization has identified antimicrobial resistance as one of the century’s most serious global health threats. The problem involves dangerous pathogens, including Staphylococcus aureus, Klebsiella pneumoniae, non-typhoidal Salmonella, and Mycobacterium tuberculosis.

Novel Sulfur-Based Polymer Shows Promise
“Importantly, the antimicrobial does not harm human or plant cells, so it has potential in medicine and agriculture,” says Professor Justin Chalker, whose research group recently created an innovative photochemical reaction used in the new study published in Chemical Science.

“The new antimicrobial is a sulfur-rich polymer material which overcome previous limitations in sulfur-based preparations and shows impressive potency against a variety of fungal and bacterial pathogens.”

Sulfur and sulfur-based compounds have been used as antimicrobials for many years, but they are often malodorous (strong smelling) and difficult to formulate because of their limited solubility.

Inside a fusion reactor, matter is heated to temperatures hotter than the Sun and confined by powerful magnetic fields. But keeping this superheated plasma stable long enough to produce usable energy remains one of the field’s toughest challenges.

One major problem is that the plasma edge can unleash violent bursts of energy capable of damaging reactor walls, while the exhaust system must also withstand enormous heat loads comparable to those on a spacecraft during reentry.

Now, researchers in China may have found a way to tackle both issues at once.

A team led by Professor Guosheng Xu at the Institute of Plasma Physics, part of the Hefei Institutes of Physical Science under the Chinese Academy of Sciences, has demonstrated a new plasma operating regime on the EAST fusion device that simultaneously reduces heat striking reactor components, suppresses damaging instabilities, and maintains strong energy confinement. The achievement, sustained for roughly a minute in a metal-wall environment, was recently published in Physical Review Letters.

Fusion Challenges: Heat Loads, ELMs, and Stability
Fusion reactors work by confining plasma — an extremely hot, electrically charged gas — inside magnetic fields. For fusion power plants to operate continuously, they must maintain high temperatures and strong confinement while safely removing excess heat and particles from the plasma edge.

One of the most vulnerable regions is the divertor, a specialized exhaust system that handles escaping heat and particles. Under normal conditions, the divertor can experience immense heat fluxes that threaten to erode reactor materials. Scientists often inject small amounts of impurity gases to cool this region through a process called detachment, where the plasma partially separates from the divertor surface. However, excessive cooling can also reduce the plasma’s performance.

Another major issue involves edge-localized modes, or ELMs, sudden eruptions of heat and particles from the plasma edge that behave somewhat like solar flares. These bursts are common in high-confinement, or H-mode, plasmas, which are otherwise desirable because they trap energy efficiently. Eliminating ELMs without sacrificing confinement has long been considered a key hurdle for future fusion reactors.

In the new study, the researchers precisely controlled the injection of light impurity gases inside the EAST tokamak to create what they call the Detached divertor and Turbulence-dominated Pedestal (DTP) regime.

At the Alcor facility in Arizona, more than 150 disembodied heads reportedly lie in cryogenic chambers, preserved in hopes that future medical advances can bring these brains back to life in new bodies. Given that scientists still cannot revive a cryogenically preserved brain, why do patients bother with cryonics at all? Why couldn't these heads just be stitched onto new bodies in the present day, when they're still fresh? In other words, why isn't a brain transplant possible?

Dr. Max Krucoff, an assistant professor of neurosurgery at the Medical College of Wisconsin, would rather describe such a procedure as a body transplant. Unlike a patient who receives a donor heart or liver, transplanting a brain into a patient's body would make them "a completely new human being," he told Live Science. "Your agency, your identity, is contained within your brain".

Semantics aside, Krucoff said this transplant is currently impossible because surgeons cannot yet forge signaling connections between nerves in the central nervous system, which includes the brain and spinal cord. Transplanted peripheral nerves, or the nerves that branch off throughout the body beyond the brain and spinal cord, can eventually communicate with their new neighbors, since these nerve cells can regenerate. There is less evidence that the adult human central nervous system can generate fresh neurons, and if it does, it's to a limited degree. Neurons can form new connections throughout a person's lifetime, which is how learning is encoded, but scientists do not understand this pathway well enough to exploit it for a transplant.

Even a partial brain transplant, such as a cerebellum swap, is out of the question for now. In the case of the cerebellum, the structure is home to millions of specialized neurons called Purkinje cells, each of which receives signals from thousands of other neurons. "The number of connections is exponential," Krucoff said. "That's way beyond our capacity."

Our solar system is currently passing through the Local Interstellar Cloud, a region of highly diluted gas and dust between the stars. On its path, Earth continuously accumulates iron-60, a rare radioactive isotope of iron produced in stellar explosions. This has now been confirmed by an international research team led by the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) through the analysis of Antarctic ice tens of thousands of years old. From the steady but time-varying influx, the researchers conclude that the radioactive isotope has been stored within the cloud since a long-past stellar explosion. The results have been published in the journal Physical Review Letters.

Iron-60 is formed in the interiors of massive stars and is ejected into space when they explode. Geological archives show that our solar system was hit twice by iron-60 from supernovae millions of years ago. In more recent times, however, there have been no nearby stellar explosions—and thus no direct supply of iron-60. When scientists discovered iron-60 in Antarctic surface snow less than twenty years old a few years ago, the question of its origin arose.

"Our idea was that the Local Interstellar Cloud contains iron-60 and can store it over long time periods. As the solar system moves through the cloud, Earth could collect this material. However, we couldn't prove this at the time," explains Dr. Dominik Koll from the Institute of Ion Beam Physics and Materials Research at HZDR.

In recent years, the team led by Koll and Prof. Anton Wallner analyzed additional samples, including deep-sea sediments up to 30,000 years old. Iron-60 was also found there, but competing theories remained. The new Antarctic ice samples date back 40,000 to 80,000 years. Their analysis now makes it clear: the Local Interstellar Cloud is the likely source.

"This means that the clouds surrounding the solar system are linked to a stellar explosion. And for the first time, this gives us the opportunity to investigate the origin of these clouds," says Koll.

Our solar system entered the Local Interstellar Cloud several tens of thousands of years ago and will leave it again in a few thousand years. At present, we are located near its edge.

A massive Atlantic Ocean circulation system that plays a central role in regulating Earth’s climate has been weakening for nearly 20 years, according to a new study. Scientists say the slowdown spans a large portion of the Atlantic and could eventually alter weather patterns in many parts of the world.

The research, led by scientists at the University of Miami Rosenstiel School of Marine, Atmospheric and Earth Science, provides some of the strongest direct observational evidence so far that the Atlantic Meridional Overturning Circulation (AMOC) is losing strength. Researchers say the findings could improve climate forecasts and help scientists better understand how global warming may affect future weather and ocean conditions.

“A weaker AMOC can shift weather patterns, potentially leading to more extreme storms, changes in rainfall, or colder winters in some regions,” said Shane Elipot, a senior author of the study and physical oceanographer at the Rosenstiel School. “It can also influence sea-level rise along coastlines, affecting communities and infrastructure.”

Why the AMOC Matters for Global Climate
The AMOC is one of the most important systems controlling climate in the Atlantic region. It helps distribute heat through the ocean, influencing temperatures, weather patterns, and sea levels, especially around the North Atlantic.

Scientists say a slowdown in the circulation could affect European winters, hurricane activity, rainfall patterns, and other climate conditions around the globe.

Researchers also believe measurements taken along the western boundary of the Atlantic may act as an early warning signal for future climate changes. They compared the monitoring approach to a canary in a coal mine because it may provide an efficient way to track long-term changes in this crucial climate-regulating system.

“This research helps scientists better predict how the climate may change in the coming decades—information that governments, businesses, and communities use to prepare for future environmental conditions,” said Elipot.

A stem cell treatment helped mice recover from strokes by rebuilding damaged brain connections, restoring blood vessels, and improving movement, according to new research from the University of Zurich and the University of Southern California. The findings raise hopes that future therapies could one day repair stroke damage that is currently considered permanent.

Stroke remains one of the world’s leading causes of long-term disability. When blood flow to part of the brain is cut off, oxygen-starved cells die within minutes. Unlike skin or bone, the brain has only a limited ability to replace lost tissue, leaving many survivors with lifelong paralysis, speech problems, or memory loss.

Scientists have spent years searching for ways to help the brain rebuild itself. In the new study, researchers used neural progenitor cells, early-stage cells capable of developing into different types of brain tissue. The cells were created from induced pluripotent stem cells, which are adult human cells reprogrammed into a stem cell-like state.

The team transplanted these cells into the brains of mice one week after a stroke. That timing turned out to be critical. Earlier transplants survived poorly because the injured brain was still overwhelmed by inflammation and toxic chemical signals. Waiting several days allowed conditions to stabilize enough for the transplanted cells to take hold.

What happened next surprised the researchers.

New Neurons and Rebuilt Connections
Over five weeks, the transplanted cells survived, spread through nearby brain tissue, and matured mostly into functioning neurons. Many became GABAergic neurons, specialized inhibitory brain cells that help regulate neural activity and are heavily depleted after stroke. These cells are essential for balancing brain signaling, preventing excessive excitation, and coordinating movement.

The grafted neurons did not simply exist alongside the damaged brain tissue. Evidence suggested they actively communicated with surrounding cells through molecular signaling systems linked to neural growth, synapse formation, and tissue repair. The researchers identified several major pathways involved in this cross-talk, including neurexin, neuregulin, NCAM, and SLIT signaling, all of which are associated with rebuilding neural networks and guiding axons to reconnect.

The stem cell treatment also appeared to trigger a broader healing response across the injured brain.

Mice receiving the transplants developed significantly more blood vessels near the stroke site, improving circulation in damaged tissue. The treatment also reduced inflammatory activity and strengthened the blood-brain barrier, the protective lining that normally prevents harmful substances in the bloodstream from leaking into the brain. Damage to this barrier is a major contributor to swelling and further injury after stroke.

Researchers additionally observed increased growth of nerve fibers around the damaged region. Some transplanted neurons extended long projections into areas linked to movement and sensory control, suggesting the new cells may have started integrating into existing brain circuits.

New research led by the University of Oxford and University College London (UCL) has revealed that pollution from coal-fired power plants is significantly reducing the energy output of solar photovoltaic (solar PV) installations, particularly where these are expanding side by side. The findings have been published in Nature Sustainability.

Global scale of solar power losses
The new study mapped and assessed more than 140,000 solar PV installations worldwide using satellite data. By combining this with atmospheric data on air pollution, the researchers calculated how much sunlight is lost and how this reduces electricity generation.

They found that aerosols—tiny particles suspended in the air—reduced global solar electricity output by 5.8% in 2023. This is equivalent to 111 terawatt-hours (TWh) of lost energy—the amount generated by 18 medium-sized coal-fired power plants.

Crucially, these losses represent a significant and often overlooked constraint on the clean energy transition. Between 2017 and 2023, new PV installations added an average of 246.6 TWh of electricity each year, while aerosol-related losses from existing systems reached 74.0 TWh annually—equivalent to nearly one-third of the gains from new capacity.

This highlights a previously unrecognized interaction between fossil fuel use and renewable energy, where emissions from one system directly reduce the performance of the other.

Cast your mind back to 1969, if you’re old enough. Before Neil Armstrong set foot on the lunar surface in July, NASA flew Apollo 9, a mission that never left Earth orbit. It docked the Command Module with the Lunar Module, tested the systems, proved the hardware worked together, and gave engineers the confidence to risk sending astronauts to the Moon. Without Apollo 9, Apollo 11 doesn't happen. NASA is about to do the same thing again.

The Artemis programme was formally established in 2017 with a clear ambition to return humans to the Moon for the first time since Apollo 17 in 1972, and this time stay. Artemis I, launched in November 2022 and sent an uncrewed Orion spacecraft around the Moon to test the rocket and capsule. Artemis II, just six weeks ago, did the same with a crew of four, the first humans to travel beyond low Earth orbit in over fifty years. The next step was expected to be the landing but it isn’t at least not yet.

Artemis III, now targeted for late 2027 has been redesigned as a crewed Earth orbit test flight, similar to Apollo 9. The Moon landing has moved to Artemis IV, scheduled for 2028. The reasons are practical though, delays in the development of both SpaceX's Starship lunar lander and Blue Origin's Blue Moon spacecraft made the original timeline untenable. So NASA has done what it does when the stakes are high enough, it’s added a rehearsal.

It’s more complex than usual though since, for the first time in history, NASA will coordinate a single launch campaign involving three separate spacecraft from multiple providers. The SLS rocket will carry a four person crew in Orion to low Earth orbit. Already waiting there will be SpaceX's Starship human landing system pathfinder and Blue Origin's Blue Moon Mark 2 pathfinder which will be launched separately by their commercial providers. Orion will then rendezvous and dock with them. For the first time, Orion's docking system will be demonstrated with crew aboard. The astronauts could even enter at least one of the landers once docked, rehearsing procedures that their successors will rely on for the actual lunar landing.

One technical detail worth noting, instead of the usual upper stage rocket to boost Orion after launch, Artemis III will use what NASA calls a “spacer", a non propulsive structure with the same mass and dimensions as the real upper stage. The Orion service module, built by the European Space Agency, will instead handle the propulsion to circularise the orbit. This approach is deliberate, low Earth orbit gives NASA more launch windows for each element of the mission, improving the chances of getting everything into place successfully.

Isotope analysis of gas from geothermal springs in Zambia could show that a new continental rift is forming, scientists say. Unexpectedly high helium isotope ratios indicate that a weakness in Earth's crust has broken through to reach the mantle beneath. This rift could eventually become a new tectonic plate boundary. In the meantime, opportunities for geothermal energy could boost local economies.

"The hot springs along the Kafue rift of Zambia have helium isotope signatures which indicate that the springs have a direct connection with Earth's mantle, which lies between 40 and 160km below Earth's surface," said Prof Mike Daly of the University of Oxford, an author of the article in Frontiers in Earth Science.

"This fluid connection is evidence that the fault boundary of the Kafue Rift is active and therefore the Southwest African Rift Zone is too—and may be an early indication of the break-up of sub-Saharan Africa."

What if the next generation of high-performance materials did not come from a factory filled with petroleum-based plastics, but from living bacteria?

Scientists at Rice University and the University of Houston have developed a new way to turn bacterial cellulose into an ultra-strong, multifunctional material that could eventually replace plastics in products ranging from packaging to electronics. Their findings, published in Nature Communications, describe a scalable manufacturing process that guides bacteria to build highly organized cellulose structures with remarkable strength and thermal performance.

Plastic waste remains a major environmental problem because synthetic plastics gradually break down into microplastics that can release harmful substances such as bisphenol A (BPA), phthalates, and carcinogens. To explore a more sustainable alternative, the team led by Muhammad Maksud Rahman, assistant professor of mechanical and aerospace engineering at the University of Houston and adjunct assistant professor of materials science and nanoengineering at Rice University, focused on bacterial cellulose, one of the purest and most abundant natural biopolymers on Earth.

“Our approach involved developing a rotational bioreactor that directs the movement of cellulose-producing bacteria, aligning their motion during growth,” said M.A.S.R. Saadi, the study’s first author and a doctoral student in material science and nanoengineering at Rice. “This alignment significantly enhances the mechanical properties of microbial cellulose, creating a material as strong as some metals and glasses yet flexible, foldable, transparent, and environment friendly.”