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A world first at the microscopic scale: Metamaterials that can shrink and expand on their own

Leiden physicists Daniela Kraft and Julio Melio have created soft structures that can take on different shapes without any external drive in their lab. They present their research on microscale metamaterials in Nature —a breakthrough that opens the door to smart, reconfigurable materials and microscopic robots.

“Metamaterials have completely changed the way we think about materials,” explains Professor of Experimental Physics Daniela Kraft. “In these systems, movements are no longer set by the material itself, but by the structure—the way particles are connected. We set out to create such functional structures at the microscopic scale. And we succeeded.”

‘Lock-and-key’ chemistry keeps cancer drugs inactive until they reach tumor sites

Many therapeutic molecules used in cancer treatments are highly toxic, often harming healthy tissues and causing significant side effects. This creates a critical need for strategies that localize their toxic activity to tumors. What if cancer drugs could stay dormant until they reach cancer cells? A new study by Syracuse University researchers demonstrates a promising chemistry-based strategy that could do just that.

Xiaoran Hu, assistant professor of chemistry in the College of Arts & Sciences (A&S), and his team introduced a prototyping “lock-and-key” system that holds therapeutic drugs in an inactive, caged form until a separate chemical trigger releases them at a specific site. The study was published in Angewandte Chemie International Edition. It introduces a new platform to control when and where chemical bonds break inside living systems.

“We are developing a broadly applicable tool that has the potential to regulate the activity of different types of therapeutics,” Hu says. “Think of this as a tool, like a hammer, that could be used on different nails.”

A robust new telecom qubit identified in silicon

Quantum technologies are anticipated to transform computing, communication, and sensing by harnessing the unusual behavior of matter at the atomic scale. Translating quantum’s promise into practical devices will require physical systems that have desirable quantum properties and can be easily manufactured. Silicon, the material behind today’s computer chips, is highly attractive as a platform because it plays to the strengths of the trillion-dollar semiconductor industry that has already been built. Identifying quantum building blocks—qubits—in silicon is, therefore, an important frontier research area.

In a new study, researchers in UC Santa Barbara materials professor Chris Van de Walle’s Computational Materials Group identified a robust new qubit in silicon, called the CN center. The work is published in the journal Physical Review B.

Qubits can be based on atomic-scale defects in a crystal. A prototype example is the NV center, which consists of a nitrogen (N) atom sitting next to a vacancy (V, a missing carbon atom) in a diamond crystal. These defects can interact with both electrons and light, allowing them to emit single photons (quanta of light) that can transmit quantum information or be processed in quantum networks.

Ion bombardment triggers a reliable quantum switch in tantalum disulfide crystals

When you toss a coin, you put it into a higher-energy state until it falls back down again. It can then end up in one of two possible states: heads or tails. No matter which state the coin was in before, after the toss both outcomes are equally likely. A team at TU Wien has analyzed a quantum system that also has two equivalent ground states. By supplying energy through ion bombardment, this state can be changed.

Remarkably, however, the system behaves very differently from a coin toss: it switches every single time. After ion impact, it reliably ends up in the opposite state. For the experiment, the ion-beam equipment of TU Wien was transported to DESY in Hamburg. The crystals studied were provided by Kiel University (CAU), which also participated in the experiments at DESY. The research is published in the journal Nano Letters.

The physics of sneaker squeaks: High-speed imaging shows how they arise from supersonic detachment pulses

Basketball shoes on a gym floor, bicycle brakes in need of a tune-up, or the squeal of tires are everyday examples of squeaking sounds. Such sounds have long been attributed to stick-slip friction, or a cycle of intermittent sticking and sliding between surfaces. While this framework explains many rigid-on-rigid systems such as door hinges, it does not fully capture the physics of soft-on-rigid interfaces, like shoes on a floor.

To shed light on this little-understood physical process, researchers at the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS), in collaboration with the University of Nottingham and the French National Center for Scientific Research, have used high-speed imaging to investigate the dynamics of soft solids sliding rapidly on rigid substrates.

In a study published in Nature, the team led by first author Adel Djellouli, a postdoctoral fellow in the lab of Katia Bertoldi, the William and Ami Kuan Danoff Professor of Applied Mechanics at SEAS, reports that squeaking emerges from a previously unseen mechanism.

Malicious NuGet Packages Stole ASP.NET Data; npm Package Dropped Malware

Cybersecurity researchers have discovered four malicious NuGet packages that are designed to target ASP.NET web application developers to steal sensitive data.

The campaign, discovered by Socket, exfiltrates ASP.NET Identity data, including user accounts, role assignments, and permission mappings, as well as manipulates authorization rules to create persistent backdoors in victim applications.

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