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X-ray snapshots reveal how viral shells change shape as they dry out

When viruses travel through the air in tiny droplets, they can quickly start to dry out. Yet many viruses remain infectious after rehydration—something that is still not fully understood. Now, an international team of researchers has directly observed at the European XFEL how the protein shells of viruses can change shape during dehydration, offering new clues to viral resilience and opening new possibilities for virology research. The results, published in Light: Science & Applications, lay the groundwork for potential applications in virology and public health and can, for instance, help develop antiviral strategies.

At the SPB/SFX instrument of the European XFEL, Abhishek Mall from the Max Planck Institute for the Structure and Dynamics of Matter in Hamburg (MPSD) and his colleagues explored the structural dynamics of the protein shells—called capsids—that enclose the genetic material of viruses. Specifically, they examined the behavior of capsids of the bacteriophage MS2 under conditions of dehydration. MS2 is an icosahedral, i.e., shaped by 20 triangular surfaces that form a sphere, single-stranded RNA virus that infects the bacterium Escherichia coli and is widely used as a model system in virology.

The capsid’s design is critical for protecting the viral genome and helping the virus interact with host cells. However, viruses are often confronted with environments that challenge their structural integrity, for example through dehydration. Theoretical studies have long suggested that capsids may undergo low-energy “buckling transitions”—sudden changes in shape—to adapt to such stresses, but direct experimental evidence has been lacking.

A magnetic field that kills superconductivity can also bring it back

Magnetic fields are generally known to destroy superconductivity in a material. However, in exceptional cases, they can lead to what is known as “re-entrant superconductivity”—where superconductivity disappears as expected, but then unexpectedly returns when the magnetic field is increased further.

This behavior is sometimes seen in bulk, three-dimensional materials, but now, in a study published in Science Advances, a team led by the RIKEN Center for Emergent Matter Science (CEMS) in Japan has seen the phenomenon in a very thin conducting layer at the boundary between two insulating oxide materials. Because oxide interfaces can be precisely engineered and controlled, the discovery provides a new platform for investigating unconventional forms of superconductivity and the quantum mechanisms that allow it to survive under unusual conditions.

Quantum squeezing sidesteps the limits on mechanical transducers

From detecting the ripples of colliding black holes to imaging individual chemical bonds, mechanical transducers have repeatedly transformed our understanding of the universe. So far, however, the sensitivity of these devices has been intrinsically limited by the laws of quantum mechanics itself.

Through new research published in Physical Review Letters, researchers led by Lukas Novotny at ETH Zurich have found a way to push past that ceiling using a quantum trick called squeezing, opening a new chapter in precision measurement.

Room-temperature laser hits record stability with 68-cm optical cavity

Scientists at NPL have demonstrated the best-reported laser frequency stability achieved with an optical reference cavity operating at room temperature, marking a major advance in ultrastable laser technology. The team’s results have been published in Optica.

Ultrastable lasers produce light of exceptional spectral purity and are a critical enabling technology for optical atomic clocks. These are the next generation of atomic clocks based on atomic transitions in the optical domain. These clocks underpin the most precise timekeeping ever achieved and are central to future technologies ranging from advanced navigation to fundamental physics.

The NPL team measured a fractional frequency instability of 4 × 10⁻¹⁷, achieved for the first time using a room-temperature optical reference cavity. Until now, comparable performance had only been realized internationally using complex cryogenic systems.

Out of darkness, blind Mexican cavefish illuminate brain evolution

Deep within the dark caves of northeastern Mexico lives a fish that has spent hundreds of thousands of years adapting to a world without light. The blind Mexican cavefish (Astyanax mexicanus) has evolved in perpetual darkness, losing its eyes and pigmentation while developing remarkable adaptations that help it survive in nutrient-poor environments.

Now, scientists are using this extraordinary species to uncover how evolution rewires the brain and shapes behavior. Because Astyanax exists both as sighted surface fish and as more than 30 independently evolved cave populations, researchers can directly compare how life in darkness alters sensory systems, neural circuits and behavior.

With new genetic tools and advanced imaging technologies that allow scientists to watch brain activity in real time, this unique fish is providing unprecedented insights into how animals adapt to extreme environments—and how evolution transforms the brain itself.

Synthetic DNA toolkit expands scientists’ ability to recognize genetic targets

A new method for recognizing and targeting DNA that dramatically expands the range of genetic sequences scientists can identify has been developed by experts at the University of Portsmouth. Published this week in Nature Communications, the research opens new possibilities for gene-targeting technologies, molecular diagnostics and DNA nanotechnology.

Dr. David Rusling, associate professor in bioengineering from the University of Portsmouth’s School of Medicine, Pharmacy and Biomedical Sciences, said, Our lab develops synthetic molecules that can recognize and bind to unique gene sequences. By introducing synthetic DNA bases into these molecules, we’ve been able to significantly improve how they recognize their targets.

I’ve worked in this area for around 20 years, and this is the first time we’ve had a system that combines strong recognition under physiological conditions with building blocks that are commercially available to other researchers.

Ultrafast X-rays allow researchers to ‘watch’ how molecules rearrange during a chemical reaction controlled by light

Since the 1980s, researchers have sought to use laser light to control chemical reactions relevant to photochemistry, catalysis and light-responsive materials. But this technique, known as coherent control, has a blind spot: There has been no way to directly see the molecules in these reactions as their structures rearrange.

Now, researchers at the Department of Energy’s SLAC National Accelerator Laboratory have imaged a coherently controlled chemical reaction for the first time. Their work, published in Physical Review A, uses ultrafast X-rays from the Linac Coherent Light Source (LCLS) to show in real time how atoms move in a molecule that was excited and manipulated with laser light.

“There are many challenges with controlling chemical reactions, but seeing is believing,” said study lead author Tom Hopper, assistant professor at the University of Central Florida who was a postdoctoral researcher at SLAC at the time of the study. “If you can see something directly, it opens up a new level of control.”

Artificial DNA tiles could deliver drugs and monitor neurons non-disruptively

Living cells constantly exchange ions (i.e., charged particles) via the thin barrier that surrounds their interior, known as the outer membrane. Neuroscientists and medical researchers have long been trying to devise effective methods to measure this exchange of ions, which is known to be associated with communication between neurons and various other crucial physiological processes.

While techniques developed so far work relatively well, they rely on inserting tiny pipettes or electrodes into cells. These tools inevitably pierce the cells’ outer membranes, damaging cells and disrupting the intracellular milieu and machinery.

Researchers at Purdue University and University of Illinois Urbana-Champaign recently nanoengineered new biohybrid devices based on artificial DNA that could be used to track electrical signals sent or received by cells without breaking through the membrane and disrupting their functions.

‘Collapsible scissored surfaces’ complete trilogy of metamaterial design principles

Over the past decade, Professor L. Mahadevan’s Soft Math Lab at the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) has helped establish how the ancient Japanese paper arts of folding or cutting can be used to inversely design structures that transform dramatically in shape and function. Now, the researchers have created a new class of shape-changing matter, based not on folds or cuts, but linkages—networks of interconnected scissor mechanisms that collapse into lines and deploy into curved surfaces.

The study published in the Proceedings of the National Academy of Sciences, led by physics graduate student Noah Toyonaga, establishes a mathematical and physical framework for what the authors call collapsible scissored surfaces—deployable lattices of two-bar linkages that can transform from a one-dimensional collapsed state into two-dimensional structures with prescribed geometry.

“Origami showed how folds can encode shape,” said senior author Mahadevan, the Lola England de Valpine Professor of Applied Mathematics, of Organismic and Evolutionary Biology, and of Physics. “Kirigami showed how cuts can unlock motion and functionality. This work asks a complementary question: What can be achieved when the basic building block is not a fold or a cut, but a linkage?”

Scientists catch classical space-time crystals moving like Majorana quasiparticles

A research team from Hiroshima University, the University of Colorado, and other collaborators have demonstrated that space-time crystals—exotic structures that, under external drive, loop endlessly through both space and time—can be created using everyday liquid-crystal materials.

For the past decade, physicists have been fascinated by time crystals. Unlike normal crystals (such as salt or diamonds), which have repeating molecular patterns in space, time crystals have patterns that repeat at regular intervals in time. Previously, scientists believed these bizarre structures could exist only in highly complex, fragile quantum systems at near-absolute-zero temperatures, such as trapped ions or quantum simulators. However, in a collaborative study published in Nature Communications, researchers successfully created them in a classical, room-temperature liquid-crystal system.

To achieve this, the team took a liquid-crystal material—similar to the fluid used in smartphones and television screens—and doped it with ionic substances. They then applied a rhythmic, repeating electrical signal to the fluid. Using advanced computer models and optical microscopes, the researchers observed a surprising phenomenon known as period-doubling. Even though the electrical drive pumped energy into the fluid at a set internal rhythm, the liquid crystals spontaneously locked into a pattern that repeated only every two cycles of the electricity.

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