Browse Articles

Realization of the quantum anomalous Hall effect in germanene/NiXY (X, Y = Br, I, and X ≠ Y) heterostructure through proximity coupling

Proximity-induced exchange interactions present a novel avenue for manipulating physical properties in spintronic materials. The germanene (Ge) monolayer exhibits metallic behavior, and the NiXY (X, Y = Br, I, and X ≠ Y) monolayer displays semiconducting behavior. Here, utilizing first-principles calculations, we investigate the magnetic characteristics and topological properties in Ge/NiXY heterostructures induced by proximity coupling. Phonon dispersion and ab initio molecular dynamics simulations confirm their dynamical and thermal stability. Both heterostructures demonstrate in-plane magnetic anisotropy. The critical transition temperatures for Ge/NiBrI and Ge/NiIBr reach up to 108 and 85 K, respectively. With spin–orbit coupling, the Ge/NiBrI heterostructure exhibits half-metallicity, whereas the Ge/NiIBr heterostructure possesses a bandgap of 20.3 meV. Their electronic properties are robust against variations in the Hubbard U values. Remarkably, the Ge/NiIBr heterostructure hosts the quantum anomalous Hall effect with Chern number C = −1, and the easy magnetization axis transitions from in-plane to out-of-plane upon modulation of the interlayer distance. These results establish a versatile platform for proximity coupling engineering and enable practical quantum anomalous Hall devices.

Synergistic action of different molecular mechanisms causes striking levels of insecticide resistance in the malaria vector <i>Anopheles gambiae</i>

Intensifying insecticide resistance in the malaria vector Anopheles gambiae poses a serious threat to the progress achieved the last decades in reducing malaria deaths in Africa. The genetic basis of insecticide resistance is often complex, involving multiple genes and mutations. However, we still lack a clear understanding of how each mechanism contributes to overall resistance and how highly resistant phenotypes arise. In this study, we generated a suite of transgenic An. gambiae strains carrying either individual mechanisms or combinations that frequently co-occur in nature. We show that co-overexpression of different detoxification enzymes (CYP6P3, CYP6M2, CYP9K1, ABCH2, GSTE2, and COEAE6G), as well as the overexpression of detoxification enzymes in the presence of target site resistance mutations, can lead to substantially greater levels of resistance. Our findings suggest that increased resistance strength is a primary driver for selection of multimechanism resistance and are transformative for the scientific insight required to design robust molecular diagnostics for timely and reliable resistance detection in the field. We further show that P450 based resistance can constitute an Achilles heel for highly resistant mosquitoes, making them more vulnerable to proinsecticides; compounds that typically require P450 activation. Our results advance our understanding of the mechanistic basis of insecticide resistance and have important implications for the design and implementation of effective and evidence-based resistance management strategies.

Study on the effect of shear strain on the critical temperature of MgB2 superconductors

Enhancing the superconducting transition temperature (Tc) is crucial for expanding the practical applications of superconductors. As a binary superconductor with strong application potential, MgB2 has been widely studied under hydrostatic, uniaxial, and biaxial strain, whereas the effects of shear strain remain largely unexplored. In this work, we systematically investigate how shear strain regulates the superconducting properties of MgB2 using first-principles density functional theory and the McMillan–Allen–Dynes formula. We calculate the stress–strain response of MgB2 under shear along the (001)[110] and (001)[11¯0] directions, together with the corresponding changes in Tc, electronic structure, phonon dispersion, and electron–phonon coupling. The calculated Tc of unstrained MgB2 is 38 K, in good agreement with the experimental value of 39 K. Under shear in the (001)[110] direction, Tc first decreases at a strain of 0.02, then increases monotonically, reaching 42 K at a strain of 0.16. Under shear in the (001)[11¯0] direction, Tc also decreases first and then increases, with a minimum of 36 K at a strain of 0.08 and a maximum of 42 K at a strain of 0.20. The Tc enhancement mainly arises from the combined effect of significant softening of strain-induced low-frequency phonons, especially the E1u and acoustic branches, and electronic-structure renormalization, including changes in the density of states near the Fermi level, which together strengthen electron–phonon coupling. This work provides guidance for understanding shear-strain effects in layered superconductors such as MgB2 and suggests new theoretical routes for optimizing Tc in layered superconducting materials.

Shape instabilities of active epithelial domes under hydraulic stress: Growth, collapse, and oscillation

Fluid-filled epithelial cavities arise in a wide range of biological contexts, from developmental lumens and embryonic cavities to epithelial domes formed by monolayer delamination. Yet how hydraulic pressure and adhesive rupture coordinate their dynamic shape changes remains poorly understood. Here, using Madin-Darby Canine Kidney (MDCK) epithelial domes as a model system, we combine live imaging with a minimal theoretical model to elucidate the mechanisms governing liquid dome shape dynamics. Our model integrates active ion transport, strain-stiffening tissue mechanics, and cell–cell adhesion rupture-healing kinetics. We identify five distinct dynamic phases: collapse, stable growth, growth-collapse, oscillation, and unbounded growth. These phases emerge from the competition between ion-pumping-induced hydraulic pressure and fracture of cell-substrate and cell–cell adhesions. Crucially, the hydraulic feedback between osmotic influx and rupture-mediated leakage produces self-sustained oscillations akin to stick–slip instabilities in fracture mechanics. Pharmacological experiments further validate the model’s predictions that active ion pumping and adhesion strength control both the observed phase transitions and the characteristics of oscillatory phase. Consistent with the model predictions, measuring the hydrostatic pressure via 3D traction force microscopy reveals that pressure increases with enhanced ion transport and cell-substrate adhesion, but decreases with reduced cell–cell adhesion. These findings establish hydraulic fracture as a central regulator of epithelial dome morphodynamics and suggest a physical mechanism that may contribute to lumen formation and stability in developing tissues.

Merging bound states in the continuum to enhance the Purcell effect in nanostructures

High-refractive-index dielectric subwavelength resonators enable the enhancement of spontaneous emission at the nanoscale. Merging bound states in the continuum (M-BICs) can suppress radiation losses and achieve an ultrahigh quality factor (Q-factor), offering an important platform for tailoring spontaneous emission. Herein, we investigate the Purcell effect in finite-size structures based on M-BICs. The proposed nanostructure consists of a metagrating composed of the phase-change material antimony selenide (Sb2Se3). By merging two accidental BICs, each with a topological charge of +1, M-BICs at the Γ point are constructed. This M-BICs exhibits high robustness and enable an enhanced Q-factor in finite-size nanostructures, thereby boosting the Purcell effect. A finite structure with four unit cells retains a high Q-factor of approximately 7.6 × 103 with a Purcell factor approaching 1.3 × 103. Moreover, the Purcell effect can be actively tuned by changing the crystallinity of Sb2Se3. This work provides a viable scheme for tunable light–matter interactions in finite-size structures, with potential applications in low-threshold micro/nanolasers, high-performance quantum light sources, and so on.

Correction for Patel, The simplicity of the Hodge bundle

Impact of mechanical scratches on the structural, thermal, and electronic properties of monocrystalline silicon

The influence of intrinsic and extrinsic defects on the electronic, thermal, and structural properties of monocrystalline silicon was investigated using photothermal radiometry (PTR), photoacoustic (PA) methods, x-ray diffraction (XRD), and electrical characterization. A p-type silicon wafer (ρ = 0.005 Ω cm) was analyzed as a complete wafer, and a 1 cm2 sample was cut from the wafer center. The 1 cm2 silicon sample was examined before and after introducing one and two orthogonal central scratches. Mechanical defects were characterized by atomic force microscopy (AFM) to determine scratch width and depth. AFM measurements identify localized surface buckling and topographic deformation. In damaged regions, PTR and PA mapping revealed a decrease in thermal diffusivity from 0.97 to 0.15 cm2s−1. XRD analysis showed a slight shift of the (400) diffraction peak from 69.124° to 69.146° and an increase in full width at half maximum from 0.049° to 0.060°, indicating lattice distortion. Structure refinement of diffraction patterns showed that the lattice strain increased from 0.103% before scratching to 0.295% after scratching. Electrical resistivity measurements using the van der Pauw method indicated increased disorder, reducing measurement reliability in cut samples due to structural non-homogeneity and disruption of the electron mean free path. The results establish a correlation between extrinsically induced mechanical lattice disorder and intrinsic defects due to carrier distribution, which causes the degradation of thermal and electronic transport, and highlight the sensitivity of PTR and PA techniques for the non-destructive detection of surface damage in silicon wafers.

Correction for Sabzehei et al., Exploring PrP ^C unfolding as a critical step preceding its refolding in the context of PrP ^Sc propagation

Low-index and thin-film material characterization in the terahertz range via dielectric waveguide evanescent-field interaction

Terahertz (THz) and millimeter-wave (mmW) spectroscopy provide non-ionizing, label-free access to the electromagnetic response of a wide range of materials, enabling applications in quality control, biomedical diagnostics, and non-destructive evaluation. Conventional free-space THz spectroscopy, however, often suffers from limited interaction length and reduced sensitivity when the sample is thin, spatially localized, available only in small volume, or incompatible with beam-based fixtures. In this work, we present an integrated, non-contact approach for broadband material-property extraction based on the evanescent field of a low-loss high-resistivity silicon dielectric waveguide. The material under test (MUT) is placed in the cladding region, where it perturbs the guided-mode propagation constant and attenuation. By measuring the complex transmission through a reference waveguide and a waveguide loaded with the MUT and by combining these data with mode simulations and a perturbation-based inversion, we extract the complex permittivity over a continuous frequency band. The approach leverages an evanescent-field-based non-destructive method, a compact measurement setup, and feasibility to rescale toward higher frequencies for broadband material screening in the mmW to THz range.

Assessing the feasibility of collective licensing of in-copyright works as training data for generative AI systems

Copyright owners have sued several developers of large-scale generative AI systems for copyright infringement because of their uses of massive quantities of in-copyright works as training data for building AI models. Fair use will be the main defense against these charges. If fair use defenses succeed, developers will be free to continue to commercially exploit models already built on copyrighted data as well as to use these data to train new models or fine-tune existing ones. If copyright owners prevail, developers may be liable for billions of dollars of damages. Developers could also be enjoined from further model development on in-copyright works and even ordered to destroy models trained on infringing works. Numerous commentators have proposed collective licensing as a compromise solution to the copyright-training-data dilemma. Other commentators have questioned the feasibility of such a compromise. This article discusses several proposals for collective licensing to enable development of generative AI systems while providing some compensation to copyright owners. It assesses the complex normative, economic, and practical problems that must be addressed if such a regime is to become feasible. It discusses the implications of a licensing mandate not only for the large firms whose models are widely used today, but also for start-ups, research centers, and higher education developers of generative AI systems, as well as the general public.

Micro-photoluminescence mapping of photonic heterogeneity in cellulose nanocrystal films

Cellulose nanocrystals self-assemble into cholesteric liquid-crystalline structures that exhibit photonic bandgaps in the visible range. While the morphology of cellulose nanocrystal films has been widely studied, the relationship between microscale domain structure and local photoluminescence modulation by photonic bandgap effects remains insufficiently understood. Here, Rhodamine 6G is incorporated into cellulose nanocrystal films and spatially resolved micro-photoluminescence mapping is used to probe this relationship. Films cast under controlled humidity form relatively larger domains with fewer boundaries and exhibit lower spontaneous photoluminescence intensity due to a redshift of the photonic bandgap away from the dye emission and increased scope for dye aggregation during slow drying. In contrast, films cast at room temperature under ambient conditions exhibit smaller domains with a higher density of boundaries and enhanced emission at low dye concentration (0.05 wt. %), where spectral matching between emission and reflection is strongest. Increasing the dye concentration up to 0.5 wt. % does not enhance emission, but instead contributes to spectral detuning and, together with concentration-dependent quenching, reduces photoluminescence. Quantitative spectral-overlap analysis confirms that emission intensity is governed primarily by reflection–emission proximity rather than dye concentration alone. This work establishes micro-photoluminescence mapping as a sensitive approach for linking microscale structural heterogeneity to local optical response in cellulose nanocrystal-based photonic materials.

Shifting cultivation as a self-organizing social–ecological system

Electrical discharge radiation source for the wavelength region below 10 nm

The results of the experiments with potentially “clean” electrical discharge source of extreme ultraviolet (EUV) radiation with wavelength below 10 nm are presented. The operation of the source is based upon the use of the early stage of vacuum discharge with external triggering. The main feature of the stage under consideration is the presence of the voltage across the discharge gap. The phenomenon involves the acceleration of the electrons, emitted by trigger plasma under the action of the applied electrical field, evaporation, and finally, ionization of the anode material driven by the accelerated electrons. No plasma pinching and electrode melting take place. The operation of such a discharge as an EUV source was demonstrated in the spectral range 10–20 nm for 10 kV. A more advanced discharge circuit proposed in the present work made it possible to increase the working voltage from 10 to 34 kV. This step has allowed to operate at shorter wavelength regions. The use of rare earth metals (Nd, Sm, Tb) as anode materials allowed us to get radiation with spectral maxima at 8.3, 7.5, and 6.8 nm, respectively.

A transition toward flightlessness in Mallards, Indian Runner Ducks, and their hybrid offspring

Many studies have explored wing function in volant birds, and how flight is gained over ontogeny and evolution. However, flight is often secondarily reduced or lost, and how birds transition from wing- to leg-dependence is unknown. Most losses occurred long ago, so stages of wing reduction have never been functionally evaluated or even observed. Here, we assess the anatomical changes and locomotor consequences of a transition toward flightlessness in a unique group: flying Mallards ( Anas platyrhynchos ), flightless Indian Runner Ducks (Mallard-derivative), and their experimentally produced hybrid offspring. Based on wild birds, we hypothesized that shifts in development would lead to wing reductions in Hybrids and especially Runners, with compensatory increases in leg size and performance. Our results show that Runners indeed share many features with wild flightless birds, and that Hybrids are intermediate. However, the assembly of these features is surprising. Wings become relatively smaller due to increases in body size rather than reductions in wing area or muscle, which are conserved. Legs, in contrast, are labile: Runners invest proportionally less in their leg muscles as juveniles but more as adults than Mallards. This contrast between wing conservation and body and leg peramorphosis suggests that for at least some flight losses, bodies and legs change before wings, which get proportionally smaller before being reduced. Given that juveniles with incipient flight and adults with reduced flight both engaged their wings and legs cooperatively, wing-leg coordination may facilitate shifts along a flightless-to-flying spectrum, exemplifying how specialized structures can be gained or lost.

Non-linear in-plane spin current in spin–orbit coupled 2D hole gases

The non-linear transport of charge and spin due to the emergence of band geometric effects has garnered much interest in recent years. In this work, we show that a linear in-plane spin current vanishes, whereas a non-linear (second-order) in-plane spin current exists for a generic two-dimensional system having time-reversal symmetry. The intrinsic second-order spin current originates from the spin Berry curvature polarizability. The formulation when applied to 2D hole gases with the k3 Rashba spin–orbit coupling reveals the existence of both transverse and longitudinal second-order spin currents normal to the spin orientation. Interestingly, anisotropic spin–orbit couplings can generate collinearly polarized spin current (spins polarized in the direction of spin current) in the second-order. The effects of anisotropy are explored by introducing an additional Dresselhaus spin–orbit coupling and electromagnetic radiation over the isotropic Rashba system. The generation and control over the multiple in-plane spin currents may have important applications in spintronic devices.

Context matters: Interpreting antiphage phenotypes and synergies of a DNA-intercalating agent

Defect concentration analysis: Combining Laplace deep-level transient spectroscopy with constrained curve fitting

Deep-level transient spectroscopy is the standard technique for characterizing electrically active defects in semiconductors. The conventional double-boxcar evaluation fails when multiple defect emissions overlap, causing peak broadening or merging. Two established routes overcome this resolution limitation: The numerical inverse Laplace transform resolves closely spaced emission rates but inherits regularization-dependent peak shapes that bias the recovered amplitudes, particularly for imbalanced peaks, while direct multi-exponential time-domain fitting avoids regularization yet is sensitive to noise and prone to overfitting when rates and amplitudes are determined simultaneously as free parameters. This work presents a two-step evaluation routine that combines Laplace transform analysis with constrained multi-exponential curve fitting of the capacitance transient. The inverse Laplace transform first identifies the emission rates, which are then held fixed in a constrained least-squares fit that recovers the individual amplitudes from the time-domain transient, thereby combining the rate resolution of Laplace DLTS with a noise-robust, regularization-free amplitude determination. The method requires no material-specific assumptions and is applicable wherever Laplace DLTS can resolve multiple defect emission rates, providing a practical tool for quantitative defect concentration analysis in semiconductor development. Validation with synthetic data demonstrates accurate recovery of defect concentrations. Application to n-type GaAs, where the well-known EL2 defect overlaps with the ELO level, reveals ELO at a concentration 20 times lower than that of EL2. Despite this difference, the order-of-magnitude higher capture cross section of ELO renders both defects comparably important for carrier recombination, highlighting the importance of accurate concentration determination via the presented method.

The dual face of miR-146a in ALS

Poling-field modulation of electric polarization in multiferroic phases of MnWO4

Type-II multiferroics host spin-driven ferroelectricity with strong magnetoelectric coupling. Here, we report the first successful growth of high-quality MnWO4 single crystals using chemical vapor transport, unlike previous flux or optical floating-zone methods. We systematically characterized their magnetic and ferroelectric properties. In the incommensurate helical AF2 phase, which lies between approximately 8 and 13 K, we observed the expected spin-driven electric polarization. This polarization can be effectively tuned by an external poling electric field Ep, demonstrating controllable domain wall depinning. To interpret these results, we performed phenomenological Landau–Ginzburg simulations incorporating a distribution of pinning potentials. Our findings provide a clear experimental basis for manipulating macroscopic magnetoelectric responses in type-II multiferroics.

Public responses to atrocities depend on partisanship and context, not legal labels

Legal labels such as genocide and crimes against humanity carry substantial legal and diplomatic weight in elite and institutional arenas, where classification shapes treaty obligations, ICC jurisdiction, and the perceived stakes of inaction. A common assumption in advocacy and policy discourse is that these labels also shape mass public judgment. Direct evidence is limited and ambiguous. We test this assumption in a preregistered, nationally representative survey experiment ( N = 2 , 000 ) comparing four legally salient atrocity terms—genocide, war crimes, crimes against humanity, and ethnic cleansing—against a nonlegal control across five real-world conflict contexts, measuring support for punitive and humanitarian policies as well as moral attributions of responsibility. Across outcomes, estimated label effects are small and rarely distinguishable from zero. Critically, even within a given partisan and country context, swapping legal labels produces smaller shifts than the baseline gaps across partisan and geopolitical contexts—indicating that where you stand and who you are matter far more than what word is used. Any departures from zero are narrow and do not accumulate into a consistent pattern across outcomes or conflicts. These results suggest that the political significance of atrocity labeling lies primarily in elite and institutional arenas; for mass publics, legal terminology is a weak lever compared to country context and partisan commitments.