Salinization of freshwater and soils adversely affects 500 million people around the world, especially in low-lying river deltas.

A new study led by researchers at the University of Portsmouth, in partnership with Dhaka University and Curtin University, sheds light on how rising oceans are pushing saltwater into freshwater rivers and underground water sources in the world’s largest river mouth — the Bengal Delta in Bangladesh.

Drawing on nearly two decades of data from over 50 monitoring stations in coastal Bangladesh, the team tracked a consistent rise in salt levels in rivers and estuaries, particularly since the mid-2000s.

The western parts of the delta, already more prone to tidal influence, showed the fastest increases in salinity. The data suggests that the combination of sea-level rise, reduced freshwater flow, and increasingly frequent storm surges are all contributing to the inland movement and retention of saltwater.

Since around 2007, many parts of the delta have experienced stepwise increases in salinity, often linked to powerful storms like Cyclone Sidr. These changes can devastate crops, erode food security, and force communities to move. While the analysis focused primarily on environmental data, it underscores how salinity intrusion is increasingly a threat to livelihoods, public health, and regional stability.

The study, published in Ecological Indicators, uses one of the most detailed and long-running salinity datasets in any delta system worldwide. It applied advanced statistical methods to distinguish long-term trends from short-term weather or seasonal changes.

The researchers introduced a new conceptual model called the Offshore Controlled Estuarine and Aquifer Nexus (OCEAN) framework, that highlights how offshore features like steep underwater slopes and restricted tidal flows can trap salt in low-lying coastal zones.

Dr Mohammad Hoque from the University of Portsmouth’s School of the Environment and Life Sciences: said: “What we’re seeing in the Bengal Delta is not just a local crisis, it’s a signal of what’s coming for low-lying coastal areas around the world.

“Salinity is rising faster and reaching farther inland than many people realise, and it’s happening quietly with major consequences for water security, agriculture, and livelihoods. This study helps us understand the mechanics behind it, and underscores the urgency for coordinated, global action.”

The findings also show the limits of relying only on land-based solutions. Human interventions like embankments, riverbed alterations, and upstream dams have often made things worse by restricting freshwater flows.

Meanwhile, offshore dynamics — such as sediment build-up and ocean current shifts — play a larger role than previously appreciated. Addressing the problem, therefore, requires integrated approaches that connect rivers, oceans, and climate systems.

Coastal regions in California, including Los Angeles County and the Sacramento-San Joaquin Delta, are combating saltwater intrusion through innovative measures. In LA, freshwater is injected into aquifers to create hydraulic barriers against seawater. However, population growth and groundwater extraction continue to challenge these efforts.

“While the focus is on Bangladesh, the study’s implications are global,” said Dr Sean Feist, former PhD researcher at the University of Portsmouth and now Scientific Officer at Test Valley Borough Council. “Coastal regions from the Mekong Delta in Vietnam to Louisiana’s wetlands in the United States face similar pressures. As sea levels continue to rise, the risk of agricultural land turning salty, drinking water becoming undrinkable, and shallow groundwater becoming permanently brackish grows ever more serious.”

The paper recommends that similar long-term investigations into changing salinity levels be conducted in other vulnerable coastal regions around the world, particularly in low-lying deltas facing rising seas, reduced river flows, and increasing storm activity. Short-term datasets can often misrepresent the scale or pace of salinisation, while extended records offer a clearer picture of how saltwater intrusion evolves over time.

Dr Ashraf Dewan from Curtin University said: “Ultimately, this study highlights that the creeping salinisation of deltas is a slow-moving but deeply disruptive force. Without urgent investment in salt-tolerant agriculture, better water storage, and strategic planning across entire river basins, the disruptive impacts of salinity are likely to intensify. The Bengal Delta is on the frontline of climate change, but it is not alone. The patterns observed here are emerging in many of the world’s great coastal regions. What happens next depends on how quickly we respond.”

“This moves the blues into the domain of green lifetimes,” said Stephen Forrest, the Peter A. Franken Distinguished University Professor of Electrical Engineering and corresponding author of the study in Nature Photonics.

“I can’t say the problem is completely solved — of course it’s not solved until it enters your display — but I think we’ve shown the path to a real solution that has been evading the community for two decades.”

OLED screens are standard in flagship smartphones and high-end televisions, providing high contrast and energy efficiency as variations in brightness are achieved by the light emitters rather than a liquid crystal layer over the top. However, not all OLEDs are equally energy efficient.

In current displays, red and green OLEDs produce light through the highly efficient phosphorescent route, whereas blue OLEDs still use fluorescence. This means while red and green OLEDs have a theoretical maximum of one photon for every electron running through the device, blue OLEDs cap out at a far lower efficiency.

The trouble is that blue light is the highest energy that an RGB device must produce: The molecules in blue phosphorescent OLEDs (PHOLEDs) need to handle higher energies than their red and green counterparts. Most of the energy leaves in the form of blue light, but when it is trapped, it can instead break down the color-producing molecules.

Previously, Forrest’s team discovered that there was a way to get that trapped energy out faster by including a coating on the negative electrode that helps the energy convert into blue light. Haonan Zhao, a recent Ph.D. graduate in physics, said it was like creating a fast lane.

“On a road that doesn’t have enough lanes, impatient drivers can crash into one another, cutting off all traffic — just like two excitons bumping into one another create a lot of hot energy that destroys the molecule,” said Zhao, first author of that study as well as the new one. “The plasmon exciton polariton is our optical design for an exciton fast lane.”

The details are based in quantum mechanics. When an electron comes in through the negative electrode, it creates what’s called an excited state in one of the molecules that produces blue light. That state is a negatively charged electron that jumps into a higher energy level and a positively charged “hole” that the electron leaves behind — together, they make an exciton.

Ideally, the electron would quickly jump back to its original state and fire off a blue photon, but excitons that use the phosphorescent route tend to hang around. Simply relaxing into their original state would violate a law of quantum mechanics. However, excitons very near the electrode produce photons faster because the shiny surface supports another quantum quasiparticle — surface plasmons. These are like ripples in the pond of electrons on the surface of the metal.

If the exciton in the light-emitting material is close enough to the electrode, it gets a little help with the conversion to blue light because it can dump its energy into a surface plasmon — a phenomenon known as the Purcell effect. It does this because the exciton oscillates a little like a broadcast antenna, which creates waves in the electrons in the electrode. This isn’t automatically helpful, though, as not all surface plasmons produce photons. To get the photon, the exciton must attach itself to the surface plasmon, producing a plasmon exciton polariton.

Forrest’s team encouraged this route by adding a thin layer of a carbon-based semiconductor onto the shiny electrode that encourages the exciton to transfer its energy and resonate in the right way. It also extends the effect deeper into the light-emitting material, so excitons further from the electrode can benefit.

The team reported on this last year, and they have since been putting this effect together with other approaches to finally produce a blue PHOLED that can last as long and burn as bright as a green one. These are the highlights of the design:

• Two light-emitting layers (a tandem OLED): This cuts the light-emitting burden of each layer in half, reducing the odds that two excitons merge.

• Adding a layer that helps the excitons resonate with surface plasmons near both electrodes, so that both emitting layers have access to the fast lane

• The whole structure is an optical cavity, in which blue light resonates between the two mirror-like electrodes. This pushes the color of the photons deeper into the blue range.

This study was supported in part by the Department of Energy and Universal Display Corporation.

Claire Arneson, a Ph.D. student in physics at U-M, also contributed to this study.

The device was built in the Lurie Nanofabrication Facility and studied at the Michigan Center for Materials Characterization.

The team has patented the technology with the assistance of U-M Innovation Partnerships and has licensed it to Universal Display Corp. Forrest and the University of Michigan have a financial interest in Universal Display Corp.

Forrest is also the Paul G. Goebel Professor of Engineering and a professor of electrical computer engineering, materials science and engineering, physics and applied physics.

An international team of researchers led by Max Delbrück Center Scientific Director Professor Maike Sander has for the first time developed an organoid model of human pluripotent stem cell-derived pancreatic islets (SC-islets) with integrated vasculature. Islets are cell clusters in the pancreas that house several different types of hormone-secreting cells, including insulin-producing beta cells. Researchers in the Sander lab at the University of California, San Diego, found that SC-islet organoids with blood vessels contained greater numbers of mature beta cells and secreted more insulin than their non-vascularized counterparts. The vascularized organoids more closely mimicked islet cells found in the body. The study was published in “Developmental Cell.”

“Our results highlight the importance of a vascular network in supporting pancreatic islet cell function,” says Sander. “This model brings us closer to replicating the natural environment of the pancreas, which is essential for studying diabetes and developing new treatments.”

Engineering vascularized stem cell islets

SC-islet cell organoids — mini-organs that mirror the insulin producing cell clusters outside the body — are widely used to study diabetes and other pancreatic endocrine diseases. But beta cells in these organoids are typically immature, making them suboptimal models for the in-vivo environment, says Sander. Although several approaches have been developed to promote beta cell maturation, their effects have been modest, she adds.

To better mimic the in-vivo environment, the researchers added human endothelial cells, which line blood vessels, and fibroblasts, cells that help form connective tissue, to islet organoids grown from stem cells. The team experimented with different cell culture media until they found a cocktail that worked. The cells not only survived, but matured and grew a network of tube-like blood vessels that engulfed and penetrated the SC-islets.

“Our breakthrough was devising the recipe,” Sander says. “It took five years of experimenting with various conditions, involving a dedicated team of stem cell biologists and bioengineers.”

Vascularized stem cell islet organoids are more mature

When the researchers compared vascularized organoids to non-vascularized organoids, they found the former secreted more insulin when exposed to high levels of glucose. “Immature beta cells don’t respond well to glucose. This told us that the vascularized model contained more mature cells,” says Sander.

The researchers next wanted to explore how specifically vasculature helps organoids to mature. They found two key mechanisms: Endothelial cells and fibroblasts help build the extracellular matrix — a web of proteins and carbohydrates at cell surfaces. The formation of the matrix itself is a cue that signals cells to mature. Secondly, endothelial cells secrete Bone Morphogenetic Protein (BMP), which in turn stimulates beta cells to mature.

Recognizing that mechanical forces also stimulate insulin secretion, the team then integrated the organoids into microfluidic devices, allowing nutrient medium to be pumped directly through their vascular networks. They found that the proportion of mature beta cells increased even further.

“We found a gradient,” says Sander. “Non-vascularized organoids had the most immature cells, a greater proportion matured with vascularization, and even more matured by adding nutrient flow through blood vessels. A human cell model of pancreatic islets that closely replicates in-vivo physiology opens up novel avenues for investigating the underlying mechanisms of diabetes,” she adds.

In a final step, the researchers showed that vascularized SC-islets also secrete more insulin in-vivo. Diabetic mice grafted with non-vascularized SC-islets fared poorly compared to those grafted with vascularized SC-islet cells, with some mice showing no signs of the disease at 19-weeks post-transplant. The research supports other studies that have shown that pre-vascularization improves the function of transplanted SC-islets.

A better model to study Type 1 diabetes

Sander now plans to use vascularized SC-islet organoid models to study Type-1 diabetes, which is caused by immune cells attacking and destroying beta cells in the pancreas — in contrast to Type-2 in which the pancreas produces less insulin over time and the body’s cells become resistant to the effects of insulin.

She and her team at the Max Delbrück Center are growing vascularized organoids from the cells of patients with Type-1 diabetes. They are transferring the organoids onto microfluidic chips and adding patients’ immune cells. “We want to understand how the immune cells destroy beta cells,” Sander explains. “Our approach provides a more realistic model of islet cell function and could help develop better treatments in the future.”

But new research, led by the University of Bristol and published today in the journal Nature Electronics, could make all this and more a step closer to reality thanks to a radical breakthrough in semiconductor technology.

The futuristic concepts rely on the ability to communicate and transfer vast volumes of data much faster than existing networks. So physicists have developed an innovative way to accelerate this process between scores of users, potentially across the globe.

Co-lead author Martin Kuball, Professor of Physics at the University of Bristol, said: “Within the next decade, previously almost unimaginable technologies to transform a wide range of human experiences could be widely available. The possible benefits are also far-reaching, including advances in healthcare with remote diagnostics and surgery, virtual classrooms and even virtual holiday tourism.

“In addition, there is considerable potential for advanced driver assistance systems to improve road safety and industrial automation for greater efficiency. The list of possible 6G applications is endless, with the limit just being human imagination. So our innovative semiconductor discoveries are hugely exciting and will help drive forward these developments at speed and scale.”

It is widely acknowledged that the shift from 5G to 6G will demand a radical upgrade of semiconductor technology, circuits, systems, and associated algorithms. For instance, the main semiconductor components involved, in other words the radio frequency amplifiers made from a wonder conductor called Gallium Nitride (GaN), need to be much quicker, emit greater power, and be more reliable.

The team of international scientists and engineers has tested a new architecture, catapulting these special GaN amplifiers to unprecedented heights. This was achieved by discovering a latch-effect in GaN, which unlocked a much greater radio frequency device performance. These next generation devices use parallel channels which then require the use of sub-100nm side fins — a type of transistor which controls the flow of current passing through the devices.

Co-lead author Dr Akhil Shaji, Honorary Research Associate at the University of Bristol, explained: “We have piloted a device technology, working with collaborators, called superlattice castellated field effect transistors (SLCFETs), in which more than 1000 fins with sub-100 nm width help drive the current. Although SLCFETs have demonstrated the highest performance in the W-band frequency range, equating to 75 gigahertz -110 GHz, the physics behind it was unknown.

“We recognised it was a latch-effect in GaN, which enables the high radio frequency performance.”

The researchers then needed to pinpoint exactly where this effect occurred, by simultaneously using ultra precision electrical measurements and optical microscopy, so it could be further studied and understood. After analysing more than 1,000 fins findings located this effect to the widest fin.

Prof Kuball, who is also Royal Academy of Engineering Chair in Emerging Technologies, added: “We also developed a 3D model using a simulator to further verify our observations. The next challenge was to study the reliability aspects of latch effect for practical applications. The rigorous testing of the device over a long duration of time showed it has no detrimental effect on device reliability or performance.

“We found a key aspect driving this reliability was a thin layer of dielectric coating around each of the fins. But the main takeaway was clear — the latch effect can be exploited for countless practical applications, which could help transform people’s lives in many different ways in years to come.”

Next steps for the work include further increasing the power density the devices can deliver, so they can offer even higher performance and serve wider audiences. Industry partners will also be bringing such next generation devices to a commercial market.

Researchers at the University of Bristol are at the forefront of improving electrical performance and efficiency in a wide range of different applications and settings.

Professor Kuball leads the Centre for Device Thermography and Reliability (CDTR), which is developing next generation semiconductor electronic devices for net zero, and for communications and radar technology. It also works on improving device thermal management, electrical performance and reliability, using wide and ultra-wide bandgap semiconductors.

An international team led by researchers from the University of Adelaide and the University of Copenhagen reconstructed an 11,700-year ecological baseline for bowhead whales, which are a threatened Arctic native species.

Using computer models, fossils, and whaling records, the team mapped the location and size of suitable summer foraging habitat for bowhead whales over the entire Holocene, finding that until recently it remained constant despite significant climatic fluctuations.

However, they predict that future climate change will erode somewhere between 65-75 per cent of this foraging habitat by the end of the 21st century. In the Sea of Okhotsk, which is home to one of only four populations of bowhead whales, viable summer habitat is likely to vanish entirely by 2060.

The reason for the decline is the collapse of a tight association between bowhead whales and summer sea ice cover.

“Bowhead whales have preferred to forage amongst sea ice for many millennia,” said lead author Mr Nicholas Freymueller, from the University of Adelaide’s Environment Institute and the University of Copenhagen’s Globe Institute.

“However, Arctic sea ice has declined significantly in recent decades, and this is set to accelerate in coming decades, causing habitats where bowhead whales currently congregate in large numbers to be lost.”

The team also found that the few patches of suitable bowhead habitat predicted to remain in the year 2100 will exist outside their current distribution, directly impacting conservation policies.

“By identifying the extent and location of bowhead whale habitat that is likely to be lost in coming decades, our projections provide vital information to guide future management efforts of this emblematic species,” said Professor Eline Lorenzen, from the University of Copenhagen’s Globe Institute.

Bowhead whales are still recovering from four centuries of commercial whaling. They are considered emblematic because the ongoing threats they face are reflective of those which all Arctic marine mammal species face due to climate change.

“By using ecological models and paleo-archives to reconstruct pre-whaling distributions of bowhead whales, we were able to develop a much stronger understanding of the habitat preferences of this species that was nearly hunted to extinction,” said senior author Associate Professor Damien Fordham, from the University of Adelaide’s Environment Institute.

“This gives us improved confidence in our projections of habitat loss.”

The study, published in Ecology and Evolution, shows how past perspectives can strengthen predictions of species’ future vulnerability to rapid ocean warming.

Some spiral galaxies, including the Milky Way, exhibit a straight bar inside the spiral pattern. This bar structure helps channel gas towards the center of the galaxy where it can be used to form new stars. But why bars form in only about half of spiral galaxies, and how they influence the evolution of the galaxy are unanswered questions.

To study the evolution of spiral galaxies in the early Universe, researchers led by Shuo Huang, a project researcher at the National Astronomical Observatory of Japan and Nagoya University, used the Atacama Large Millimeter/submillimeter Array (ALMA) radio telescope to observe a massive barred spiral galaxy known as J0107a that existed 11.1 billion years ago. Located in the constellation Cetus, J0107a is a “monster” galaxy, meaning a galaxy growing rapidly in the early Universe by forming many new stars. Because they are located far away, it has been difficult to see the detailed structure of monster galaxies and determine what is driving this vigorous star formation. Recently the improved resolution provided by the James Webb Space Telescope has revealed spirals and even bars in some of the monster galaxies. J0107a is the earliest and most massive barred spiral galaxy known to date, so it is the best target for studying the evolution of barred spiral galaxies in the early Universe.

The team found that in J0107a the distribution and motion of gas in the bar is similar to modern galaxies. But compared to modern galaxies, the concentrations of gas are several times higher and the speed of the gas flow is faster, reaching several hundred kilometers per second. Astronomers believe that this massive influx of gas to the center will fuel signification additional star formation, helping to drive the evolution of this monster galaxy. This is the first time these features have been observed, and they were not predicted by theoretical or simulation models.

Huang comments, “We expect that the detailed information about the distribution and movement of gas gained through these observations will provide important clues for exploring not only the origins of the diversity of galaxies, but also the formation and evolution of more normal barred spiral galaxies.”