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Advanced sensors peer inside the ‘black box’ of metal 3D printing

With the ability to print metal structures with complex shapes and unique mechanical properties, metal additive manufacturing (AM) could be revolutionary. However, without a better understanding of how metal AM structures behave as they are 3D printed, the technology remains too unreliable for widespread adoption in manufacturing and part quality remains a challenge.

Researchers in Lawrence Livermore National Laboratory (LLNL)’s nondestructive evaluation (NDE) group are tackling this challenge by developing first-of-their-kind approaches to look at how materials and structures evolve inside a AM structure during printing. These NDE techniques can become enabling technologies for metal AM, giving manufacturers the data they need to develop better simulations, processing parameters and predictive controls to ensure part quality and consistency.

“If you want people to use metal AM components out in the world, you need NDE,” said David Stobbe, group leader for NDE ultrasonics and sensors in the Materials Engineering Division (MED). “If we can prove that AM-produced parts behave as designed, it will allow them to proliferate, be used in safety-critical components in aerospace, energy and other sectors and hopefully open a new paradigm in manufacturing.”

Beyond BMI: Analysis links fat distribution to distinct brain aging patterns

Research led by The Hong Kong Polytechnic University finds that regional fat distribution exerts distinct effects on brain structure, connectivity and cognition, revealing patterns not explained by body mass index (BMI).

Obesity has been associated with structural and functional changes in the brain, including reductions in , disruptions in white matter and impaired connectivity, which have been associated with cognitive decline.

Previous studies frequently used BMI as the central measure of obesity, a highly generalized metric that cannot capture the biological differences in fat depots. Adipose tissue in different body regions is known to affect metabolic and inflammatory pathways differently, and earlier work has suggested that visceral (around organs in the ) and leg fat contribute unequally to disease risk.

Drinking any amount of alcohol likely increases dementia risk

Drinking any amount of alcohol likely increases the risk of dementia, suggests the largest combined observational and genetic study to date, published in BMJ Evidence-Based Medicine.

Even light drinking—generally thought to be protective, based on observational studies—is unlikely to lower the risk, which rises in tandem with the quantity of alcohol consumed, the research indicates.

Current thinking suggests that there might be an “optimal dose” of alcohol for brain health, but most of these studies have focused on and/or didn’t differentiate between former and lifelong non-drinkers, complicating efforts to infer causality, note the researchers.

Through multiplexed theta waves, brain’s place cells navigate using both external and internal cues

Place cells are specialized neurons in a brain region known as the hippocampus, which have been found to fire when animals are in specific locations. These cells don’t fire randomly, but their activity is known to be organized by theta oscillations, which in rats means that they fire in sync with rhythmic brain waves between 7–9 Hz.

While many past studies have explored the role and firing patterns of place cells, the extent to which their activity is influenced by different types of spatial cues has not yet been fully elucidated. Spatial cues are essentially pieces of information that help animals and humans to determine where they are and where they should head toward to reach a desired location.

Researchers at Johns Hopkins University gathered new experimental evidence suggesting that the multiplexed theta phase coding of place cells, or, in other words, their ability to tackle different tasks in the same “wave” of theta rhythm activity, is controlled by external (i.e., allothetic) and self-motion-related (i.e., idiothetic) spatial cues.

People’s neural responses while watching videos predict whether they will become friends in the future, study finds

Throughout the course of their lives, people typically encounter numerous other individuals with different interests, values and backgrounds. However, not all these individuals will become their good friends, life partners, or meaningful people in their lives.

Many past psychology and behavioral science studies investigated the relationships between different people and what contributes to their perceived affinity to others. While some of these studies linked friendship to physical proximity, interpersonal similarities and other factors, the associated with between people have not yet been fully elucidated.

Researchers at University of California Los Angeles (UCLA) and Dartmouth College recently carried out a study exploring the possibility that people who end up becoming friends exhibit similar neural activity patterns. Their findings, published in Nature Human Behavior, suggest that people are in fact drawn to others who exhibit similar emotional and mental responses to their surroundings.

Engineers develop a magnetic transistor for more energy-efficient electronics

Transistors, the building blocks of modern electronics, are typically made of silicon. Because it’s a semiconductor, this material can control the flow of electricity in a circuit. But silicon has fundamental physical limits that restrict how compact and energy-efficient a transistor can be.

MIT researchers have now replaced silicon with a magnetic semiconductor, creating a magnetic transistor that could enable smaller, faster, and more energy-efficient circuits. The material’s magnetism strongly influences its electronic behavior, leading to more efficient control of the flow of electricity.

The team used a novel magnetic material and an optimization process that reduces the material’s defects, which boosts the transistor’s performance.

Device-independent method certifies genuinely entangled subspaces in photonic and superconducting systems

In a study published in Reports on Progress in Physics, researchers have achieved device-independent characterization of genuinely entangled subspaces (GESs) in both optical and superconducting quantum systems, completing the self-checking of the five-qubit error correction code space.

In quantum information, genuinely multipartite entangled states require the existence of entanglement correlations between any two subsystems within the system. The GES constituted by the states has application value especially in designing quantum error-correcting codes. By encoding in the subspace, it can prevent error propagation caused by local decoherence.

Scientists have constructed a new Bell inequality based on the stabilizer framework constructed, and the entangled subspace can be universally characterized by using it. Any quantum state (including mixed states) within this subspace could maximally violate this inequality, providing a theoretical basis for the self-testing of genuine entangled subspaces.

Ultrafast magnetization switching: Moving boundary challenges previous all-optical switching models

The field of ultrafast magnetism explores how flashes of light can manipulate a material’s magnetization in trillionths of a second. In the process called all-optical switching (AOS), a single laser pulse of several femtoseconds (≈10-15 seconds) duration flips tiny magnetic regions without the need for an externally applied magnetic field.

Enabling such an ultrafast control over magnetization, orders of magnitude faster than what can be achieved using a conventional magnet-based read/write head as in a magnetic hard drive, AOS is a promising candidate for novel spintronics devices that use magnetic spins with their associated as information carriers. Such devices typically consist of a stack of nanometer-thin materials, with the actual magnetic material being one of them.

Until now, the switching process was thought to happen uniformly in the magnetic material wherever the laser pulse deposits a sufficient amount of energy. In a study recently published in Nature Communications, researchers from the Max Born Institute together with collaborators from Berlin and Nancy revealed that this is not the case. Instead, there is an ultrafast propagation of a magnetization boundary into the depth of the material.

Self-locked microcomb on a chip tames Raman scattering to achieve broad spectrum and stable output

A research team has successfully developed a self-locked Raman-electro-optic (REO) microcomb on a single lithium niobate chip. By synergistically harnessing the electro-optic (EO), Kerr, and Raman effects within one microresonator, the microcomb has a spectral width exceeding 300 nm and a repetition rate of 26.03 GHz, without the need for external electronic feedback.

The research was published in the Nature Communications. The team was led by Prof. Dong Chunhua from the University of Science and Technology of China (USTC), in collaboration with Prof. Bo Fang’s group from Nankai University.

Optical frequency combs, light sources composed of equally spaced frequency lines, are essential tools in modern optical communications, , and fundamental physics research. While traditional are typically based on bulky mode-locked lasers, recent advances in integrated photonics have enabled chip-scale Kerr and EO combs.

Not Spiral. Not Elliptical. So What Exactly Is This Galaxy?

The Hubble Space Telescope has released a new Picture of the Week, and this time the spotlight is on a galaxy that refuses to fit neatly into any category. The subject, known as NGC 2,775, is located about 67 million light-years away in the constellation Cancer (The Crab). At its center lies a smooth, gas-free core that looks strikingly similar to an elliptical galaxy. Surrounding it, however, is a dusty ring sprinkled with uneven clusters of young stars, giving it the appearance of a spiral galaxy. So what is it exactly: spiral, elliptical — or something in between?

Because astronomers can only observe NGC 2,775 from a single perspective, its true nature remains uncertain. Some scientists argue that it should be considered a spiral galaxy due to its delicate ring of dust and stars. Others, however, classify it as a lenticular galaxy, a transitional type that shares characteristics of both spirals and ellipticals.

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