Milk matrix reorganization modulates oral friction and sensory perception in coffee-milk systems

A recent study has investigated how the addition of milk to coffee affects oral friction and sensory perception, revealing that the structural reorganization of the milk matrix plays a crucial role. Researchers observed that milk proteins, when interacting with coffee tannins, form aggregates that modify the lubricity of the mixture in the mouth. This phenomenon directly influences the tactile sensation and the flavor profile perceived by the consumer. This work focused on characterizing the microstructural changes that occur in coffee-milk systems. A combination of rheological and tribological techniques was used to measure friction between surfaces simulating oral tissue, as well as sensory analyses with tasting panels. The results showed that the formation of protein-tannin complexes reduces friction in the mouth, which correlates with a perception of greater smoothness and creaminess in the beverage. This advance not only provides a deeper understanding of the science behind a widely consumed beverage but also opens avenues for optimizing food products. By understanding how composition and microstructure influence tribological and sensory properties, manufacturers could develop new formulations of coffee with milk or other dairy products and beverages, adjusting texture and mouthfeel to enhance the consumer experience. Furthermore, it could have implications for the design of foods for special diets, where texture is a critical factor.

Attosecond Current Control and Timing Achieved with STM

A research team has successfully controlled and timed electric current pulses at an attosecond (10⁻¹⁸ seconds) timescale using a scanning tunneling microscope (STM). This breakthrough marks the first time electric current has been manipulated with such temporal precision in an STM, opening new avenues for studying ultrafast electronic phenomena and developing electronic devices at unprecedented speeds. The technique combines the atomic spatial resolution of the STM with the temporal resolution of ultrafast optics, overcoming the limitations of traditional methods. The experiment relied on exciting the STM tip with ultrashort laser pulses, which generated current transients in the tunneling junction. By controlling the phase of these light pulses, scientists were able to modulate the current with attosecond precision. This control was achieved by manipulating the dynamics of electrons in the STM tip, allowing for synchronized charge injection and extraction with the laser's electric field. The ability to observe and manipulate these ultrafast processes is crucial for understanding the fundamental physics of light-matter interaction at extreme temporal scales. This achievement has profound implications for materials science and nanotechnology. The ability to time and control currents at the attosecond scale could enable the development of new electronic devices operating at petahertz (10¹⁵ Hz) frequencies, far exceeding the current limits of semiconductor-based electronics. Furthermore, this technique offers a unique tool for investigating electron dynamics in materials at the atomic level, potentially leading to the discovery of new quantum phenomena and the improvement of existing technologies such as quantum computing and optoelectronics.

Bioinspired Stretchable Strain Sensors Mimic Human Skin

Researchers have developed a new type of highly sensitive and stretchable strain sensor, inspired by the structure of human skin. This device, which uses a Poisson-actuated gating mechanism, is capable of detecting multidirectional deformations with unprecedented precision. The innovation lies in the sensor's ability to amplify the strain signal by reconfiguring its internal microstructures, making it ideal for applications in soft robotics, wearable devices, and health monitoring. The Poisson effect describes how a material expands or contracts perpendicularly to the direction of an applied force. In this sensor, a network of microchannels filled with conductive liquid has been designed to undergo amplified transverse deformation due to the Poisson effect when stretched. This deformation significantly alters the geometry of the channels, which in turn causes a substantial change in electrical resistance. This biomimetic design allows for much higher sensitivity than conventional strain sensors, which often rely on more subtle changes in conductivity or capacitance. The ability to detect deformations in multiple directions simultaneously is crucial for mimicking human tactile perception and for precise control of soft robots. Prototypes have demonstrated high linearity and repeatability, maintaining their performance even after thousands of stretching cycles. This breakthrough could lead to the development of more realistic electronic skins for prosthetics, more immersive haptic interfaces, and body movement monitoring systems with superior fidelity.

Near-Field Superstrates Restore Gain in Miniaturized Helical Antennas

Researchers have developed a new technique to counteract the inherent gain loss in miniaturized helical antennas. By employing aperture-limited near-field superstrates, they have successfully restored radiation efficiency in these antennas, a crucial advancement for compact wireless devices. This method addresses a fundamental challenge in antenna design, where size reduction often compromises performance due to decreased radiation impedance and increased ohmic losses. Antenna miniaturization is essential for integration into portable electronic devices and advanced communication systems. However, smaller antennas typically exhibit lower gain and efficiency compared to their full-sized counterparts. The proposed approach utilizes superstrates that interact with the antenna's near field, modifying its radiation pattern and improving impedance matching. This allows the antenna to radiate energy more effectively, compensating for the disadvantages of its reduced size. This development has significant implications for a wide range of applications, from mobile communication and IoT (Internet of Things) devices to compact sensors and radar systems. By enabling miniaturized antennas to maintain performance comparable to larger antennas, this technology opens new possibilities for designing smaller, lighter, and more efficient wireless systems. The ability to restore gain without substantially increasing antenna volume represents a step forward in radiofrequency engineering.

Resonances control accuracy of pairwise approximation in multiterminal Josephson junctions

A recent study has investigated the accuracy with which currents in multiterminal Josephson junctions can be described by summing pairwise interactions between their terminals. These junctions, which couple three or more superconductors via a weak link, are of great interest for their potential to host topological Andreev bands, multi-pair supercurrents, and as tunable circuit elements. The research compares exact currents, obtained from a microscopic scattering model for planar junctions, with the best pairwise approximation, which allows for arbitrary nonsinusoidal couplings. The results show that, although pairwise terms capture nearly all of the energy variation in ensembles of disordered three- and four-terminal junctions, the median current error ranges from 8.0% to 21.2%. This error is approximately twice the energy error, because currents more strongly weight the multiterminal harmonics. The study extended to designed devices with up to sixteen terminals. A key mechanism controlling this error has been identified: the presence of a normal-region mode near the Fermi level that couples to three or more terminals produces large nonpairwise currents. Detuning this mode with a gate suppresses these currents. Finite-gap calculations in two clean devices confirm a drop in error from tens of percent near resonance to below one percent. An analytic single-level model provides sufficient detuning for pairwise accuracy, regardless of the terminal count. This suggests that planar junctions inherit the resonant and cotunneling regimes known from quantum dots, and that normal-state properties can identify the mode that distinguishes between them. This finding is crucial for the design and understanding of quantum devices based on multiterminal Josephson junctions, as it allows for the prediction and control of nonpairwise current phenomena. The ability to tune these effects with a gate opens new avenues for engineering supercurrents and exploring complex quantum phenomena in these systems.