Browse Articles

Reconstitution of spermatogenesis and continuous generation of functional haploid germ cells in mouse testicular organoids

Direct observation and modeling of the plateau state in sub-nanosecond spin–orbit torque switching

Spin–orbit torque (SOT) has attracted significant interest due to fast magnetization switching in next-generation spintronic devices. However, SOT-driven switching is hindered by a transient equilibrium state—termed a plateau—near the equator of the magnetization vector. Here, we experimentally observed the formation of this plateau using time-resolved magneto-optical Kerr effect measurements. The plateau persists during the current pulse due to the competition between damping-like and precessional torques. The time treach to reach this plateau sets a lower bound of pulse widths for deterministic switching. Micromagnetic simulations revealed a simple rule relating current density and in-plane magnetic field that governs treach. An empirical model based on the Landau–Lifshitz–Gilbert equation accurately reproduces these results, especially for treach below 100 ps. These findings provide practical guidelines for optimizing current pulse width in energy-efficient and high-speed SOT devices.

Alexithymia and clinical communication competence in nursing interns in China with the mediating role of self-efficacy

Expansion of Antarctic surface melt through the 21st century

Impact of bond rupture dynamics at polar and non-polar interfaces on time-dependent dielectric breakdown (TDDB) of GaN FinFETs

This Letter presents a distinct crystallographic anisotropy in the time-dependent dielectric breakdown kinetics of GaN FinFETs, revealing a fundamental divergence in failure physics between polar and non-polar interfaces. By utilizing the three-dimensional Fin architecture to decouple the contributions of the c-plane (top) and m/r/a-plane (sidewall), two competing degradation mechanisms are identified: a field-assisted ionic dissociation dominated by GaGaN–NSiN bond cleavage on polar surfaces (∼1.1 eV), vs a thermally activated covalent bond rupture on non-polar sidewalls characterized by a significantly higher activation energy (∼1.9 eV). Deep-level transient spectroscopy corroborates this mechanistic transition, distinguishing shallow Ga-related electron traps (Ec−0.47 eV) on the polar face from deep vacancy-complex traps (Ec−1.032 eV and Ev+1.2 eV) specific to the non-polar interface. Consequently, GaN FinFETs exhibit an anomalous violation of the conventional area-scaling law, demonstrating superior intrinsic reliability despite their larger active gate area. These findings establish interface crystallography as a deterministic factor in the reliability physics of GaN FinFETs power electronic.

Chaos quasi-opposition arithmetic algorithm-based Robust improved frequency regulation for restructured hybrid power system integrating renewable energy sources

Compartmentalized cytoplasmic tradewinds direct soluble proteins

Enhanced magnetoelectric coupling in vertically aligned nanocomposite thin films via ferroelectric capping layer encapsulation

Vertically aligned nanocomposite (VAN) thin films with strong magnetoelectric (ME) coupling and high magnetic anisotropy are promising for next-generation low-power storage devices. However, conventional self-assembled VANs often exhibit incomplete ME coupling due to exposed ferromagnetic (FM) phases above the ferroelectric (FE) matrix surface, which limits the strain-mediated interactions. Here, we propose a FE capping layer strategy to encapsulate exposed FM phases in VANs. This design not only increases perpendicular magnetic anisotropy from 3.08 × 104 to 9.49 × 104 J m−3 but also significantly improves both direct and converse ME coupling. The direct ME (DME) coefficient rises from 80 to 216 mV cm−1 Oe−1, while the converse ME coefficient increases from 6.32 × 10−10 to 8.17 × 10−10 s m−1, attributed to restored interfacial strain coupling. This work demonstrates that the encapsulation of FM phase by FE capping layer optimizes ME performance in VANs, offering a viable route for high-density magnetoelectronic applications.

Patch type nucleotide sequence identities between genomes from many different species facilitate illegitimate recombination

Abstract Comparative analyses of nucleotide sequences across diverse taxa, including viruses, bacteria, plants, and mammals, consistently reveal patch-type sequence identities of around 45%. These identities consist of short stretches interspersed by mismatches. Similarly, identity patterns emerge in alignments of randomized shuffled or scrambled sequences. These findings suggest patch-type identities reflect intrinsic statistical properties of the four-letter genetic alphabet. Such patterns likely function as recognition signals for illegitimate recombination, a mechanism that promotes sequence insertions, exchanges, and rearrangements without extensive homology. Patch-type identities have been observed at integration sites of foreign DNA and may play a role in evolutionary innovation and rapid diversification (e. g. SARS-CoV-2) . Simulation data support the ideas that the frequency and length distribution of matching segments can be predicted by statistical models based on base composition, yet may also create local environments conducive to recombination. Further, the statistical architecture of the genetic alphabet encodes not only biological information, but also the potential for genome remodeling and adaptation during evolution. By bridging fundamental sequence properties with biological outcomes, this study provides a framework for exploring how randomness at the nucleotide sequence level can give rise to order and complexity across the tree of life.

Synergistic dual anion regulation unlocks giant thermopower and power density in hydrogel

Abstract Harvesting low-grade heat from the environment and converting it into electricity holds the potential to power devices independent of cables or batteries. However, their effectiveness is limited by weak ion selectivity and insufficient concentration gradients. Here, we introduce the use of a calix[4]pyrrole as effective anion traps to selectively capture Fe(CN) 6 4– and Cl − anions, enabling simultaneous modulation of redox ion distribution and suppression of anion mobility under a temperature gradient. This strategy combines desolvation-induced entropy gain with thermodiffusion enhancement arising from the mobility asymmetry between cations and anions. This leads to a synergistic boost in thermopower to an impressive 8.1 mV K −1 , and results in a 20-fold increase in output power compared to the PVA/Fe(CN) 6 3–/4– system. Demonstrated through a proof-of-concept wearable device with 36 unipolar elements, our system generated nearly 3 volts under ambient conditions. This strategy offers a promising route toward thermoelectric materials with enhanced thermopower for efficient harvesting low-grade thermal energy.

Salivary mucins for turbulent drag reduction

The operational efficiency of fire suppression systems, municipal sewage networks, marine vehicles, and various other technologies are constrained by the large viscous frictional drag associated with fluid turbulence. This provides a strong incentive to develop engineering strategies that attenuate turbulence, ultimately mitigating the carbon footprint of large-scale hydrodynamic applications. We demonstrate the effective use of natural salivary mucins as a cost-effective, widely accessible drag-reducing additive. Diluted samples of human saliva are shown to substantially reduce frictional drag (up to 30%), with similar efficacy as synthetic drag-reducing polymers. Saliva contains long glycoproteins that can physically associate to form a supramolecular network with a large extensional viscosity. The non-Newtonian rheology of dilute solutions of glycoproteins makes them well-suited for turbulent drag reduction (DR). Under sustained turbulent flow conditions, the supramolecular associations of the mucin network slow the effects of mechanical degradation, resulting in more persistent DR compared to synthetic hydrocarbon polymers.

Impacts of drought and manure fertilization on soil and radish resistomes

In situ electrochemiluminescence microneedle device for real-time biomarker monitoring in vivo

Ultrafast and broadband all-optical switching in ZnO via Ga-defect modulation

By leveraging the defect properties of Ga doping, the excellent nonlinear optical (NLO) properties of zinc oxide (ZnO) can be extended to a broadband spectral range. A significant increase in the non-degenerate two-photon absorption coefficient was achieved in the visible region by systematically tuning the pump and probe wavelengths in ultrafast transient absorption spectroscopy. Simultaneously, a high modulation depth was achieved in the Ga-doped ZnO, even under excitation by an extremely low pump fluence. The specific energy level positions of Ga defects with different charge states in ZnO were determined by combining the non-degenerate resonance enhancement effect with photoluminescence spectroscopy. The improved Kerr nonlinearity in the near-infrared region resulting from Ga-related defects was also confirmed by Z-scan measurements. The real part of the figure of merit, evaluated based on the Kerr effect, was significantly superior to that of other wide-bandgap semiconductor materials. This work provides an effective strategy for designing resonance-enhanced NLO responses in wide-bandgap semiconductors via doping, as well as an important reference for developing all-optical switching across a broadband range.

Multi-scale adaptive fusion network for retinal layer and fluid segmentation in optical coherence tomography B-scans

A megawatt ultra-wide bandgap semiconductor module for pulsed power electronics

Abstract Ultra-wide bandgap semiconductors exhibit advantageous electronic properties that make them promising for high-voltage, high-power electronics applications. Building on over a decade of progress in material growth and device fabrication, discrete ultra-wide bandgap devices with power-switching capacities up to the kilowatt level have been recently demonstrated. However, a packaged, multi-die ultra-wide bandgap power module – essential for further power scaling toward industrial, biomedical, grid, and aerospace applications – has yet to be realized. Here, we present a flip-chip packaged gallium oxide power module capable of 1000 A, 1000 V pulsed power switching with fast speed and minimal reverse recovery, advancing the power capacity of ultra-wide bandgap electronics by over two orders of magnitude. To address challenges posed by high electric fields and transient power surges, we employ a high-permittivity interface design enabling device-package electrothermal co-optimization. This optimization maximizes the module’s transient thermal performance and enables full exploitation of the high volumetric heat capacity of gallium oxide—a largely untapped advantage in prior device development—alongside its high-temperature stability. The optimized ultra-wide bandgap module achieves over 1.8 MW/cm 2 pulsed power capacity density, outperforming silicon and wide-bandgap semiconductor counterparts and suggesting the promise of ultra-wide bandgap electronics in next-generation high-power systems.

MACOR glass-ceramic-based UHV cell for quantum technology applications

Compact, customizable, non-magnetic vacuum systems are a key requirement for many field applications of quantum technology based on cold atoms. We report on the development and construction of a compact, low-cost ultrahigh vacuum compatible cell using the glass-ceramic MACOR. The cell offers a CF flange connection to commercial vacuum technology, as well as high numerical aperture viewports for precise optical measurements. The presented technology shows stable vacuum pressures of <1×10−10 mbar for more than a year since the implementation into the vacuum system of a quantum gas experiment, further proving suitability for general quantum technology applications.

Multi-scalar risk drivers for a heat vulnerability assessment framework using machine learning algorithms

HR3/RORα-mediated cholesterol sensing regulates TOR signaling

Abstract Cells and organisms adjust their growth based on the availability of cholesterol, which is essential for cellular functions. However, the mechanisms by which cells sense cholesterol levels and translate these into growth signals are not fully understood. We report that cholesterol rapidly activates the master growth-regulatory TOR pathway in Drosophila tissues. We identify the nuclear receptor HR3, an ortholog of mammalian RORα, as an essential factor in cholesterol-induced TOR activation. We demonstrate that HR3 binds cholesterol and promotes TOR-pathway activation through a non-genomic mechanism acting upstream of the Rag GTPases while also restraining longer-term responses through genomic regulation. We also find that RORα is necessary for cholesterol-mediated TOR activation in human cells, suggesting that HR3/RORα-mediated signaling represents a conserved mechanism for cholesterol sensing that couples cholesterol availability to TOR-pathway activity. These findings advance our understanding of how cholesterol influences cell growth, with implications for cholesterol-related diseases and cancer.

Domain wall freezing and magnetic viscosity in helical antiferromagnet

Domain wall dynamics in antiferromagnets is of a paramount importance in designing functional materials for spintronics and data storage applications, and its studying is a challenging experimental task. We present simple and accessible ways to track domain wall fluctuations and freezing in helical antiferromagnets, both considering the existence of intrinsic magnetic moments of Hubert domain walls. Two different techniques—dynamic measurements of reversible inverse magnetostriction and measurements of static magnetic susceptibility—delineated the same temperature range of domain wall freezing in the dysprosium single crystal. The main experimental protocol in dynamic measurements was the relaxation of reversible inverse magnetostriction upon switching off applied magnetic field, like the procedure used in studying magnetic viscosity. These experiments, apart from revealing domain wall freezing, enabled us to clarify the role of domain walls and lattice contributions in the anomaly of magnetoelastic coupling just below the Néel point. Furthermore, beyond the temperature range of domain wall freezing, the kinetics of relaxation of reversible inverse magnetostriction and temperature dependence of magnetic viscosity in antiferromagnetic dysprosium agree with the classical Néel model of the thermal fluctuation magnetic aftereffect.