Browse Articles

Vibrational properties of Cu2Zn1−xCdxGeS4 solid solutions: Raman analysis and effect of thermal annealing

In this study, the Raman spectra of Cu2Zn1−xCdxGeS4 solid solutions were measured and investigated. The spectra of non-annealed samples showed the presence of three dominant bands located at around 351–359, 258, and 493 cm−1. In the case of annealed samples, Raman analysis revealed a wurtz-stannite type structure for the Cu2ZnGeS4 sample, having the most intense peak located at around 360 cm−1. For the Cu2CdGeS4 sample, the analysis allowed detection of the main peak near 358 cm−1. Additionally, a linear model to relate the change of Cd/(Zn + Cd) ratio to the Raman shift of the second intense peak was proposed.

Minute-scale control of ubiquitin-mediated degradation reveals dynamics of bacterial secreted effector-functions

Abstract Precise temporal control of protein abundance is essential for dissecting dynamic cellular processes. While degron-based systems enable rapid protein depletion in eukaryotic cells, comparable tools are lacking for bacterial effectors delivered into host cells during infection. Here, we establish AIDE (Auxin-Inducible Degradation of Effectors), a host-directed degradation platform that harnesses the ubiquitin-proteasome system to selectively eliminate secreted bacterial proteins, including membrane-integrated effectors. By integrating a minimal auxin-inducible degron (AID) tag into effector genes, AIDE enables rapid, reversible, and spatially confined degradation while preserving native expression and secretion. We apply AIDE to Chlamydia trachomatis and show, that the membrane-integrated deubiquitinase Cdu1 suppresses autophagy early and later promotes developmental transitions, whereas the integral membrane fusogen IncA remains continuously required to maintain homotypic inclusion fusion. This AIDE platform provides minute-scale, spatiotemporal control over bacterial effector activity and offers a broadly applicable framework for dissecting virulence mechanisms and host-pathogen interactions across diverse secretion-dependent pathogens.

Inside Front Cover: Oxidative Damage Fine‐Tunes G‐Quadruplex Structures in Human Gene Promoters (Angew. Chem. Int. Ed. 21/2026)

Single-transistor spectrometer via Burstein–Moss absorption edge modulation in compound semiconductors

As on-chip photonic systems evolve toward miniaturization and integration, achieving high-performance spectral analysis within a minimalist architecture remains a critical challenge, typically constrained by the trade-off between spatial resolution and spectral channels. Here, we propose a universal design strategy for a single-transistor computational spectrometer based on the gate-controlled Burstein–Moss effect, which enables the dynamic electrical modulation of the optical absorption cutoff, thereby allowing the incident spectrum to be reconstructed solely from a single current–voltage (I–V) curve. Through self-consistent simulations, systematic selection criteria for the active layer are established, prioritizing a small electron effective mass (me*) and a high band edge extinction coefficient (κ). Simultaneously, the gate dielectric design is optimized based on the trade-off between electrostatic control capability and tunneling leakage suppression. As a proof-of-concept, a miniaturized single-transistor spectrometer model integrating a GaAs-on-insulator active layer with HfO2 is numerically demonstrated. Coupled with an adaptive regularization algorithm, the spectrometer exhibits exceptional spectral reconstruction capabilities, achieving a narrowband spectral resolution of ∼4.2 nm and an ultra-high wavelength positioning accuracy of ∼0.04 nm, along with the high-fidelity recovery of dense doublets (∼6 nm separation) and broadband continuous spectra. Furthermore, it demonstrates powerful spatial-spectral decoupling capabilities in array-level imaging and exceptional algorithmic resilience against physical degradation. This work provides a versatile device design blueprint for developing low-cost, high-performance, and process-compatible on-chip integrated spectral analysis systems.

Photothermal catalytic synthesis of cyclohexanones from lignin-derived phenolic bio-oils enabling transparent and elastic polyamides

Wafer scale characterization of bulk AlN substrates and homoepitaxial growth

Aluminum nitride (AlN) is well suited to address evolving needs of future power systems for increased density, efficiency, and voltage handling. Eventual commercialization of power devices requires maturation of substrate technology to ensure fabrication of consistent devices impacted by the spatial distribution of defects and substrate inhomogeneities. Commercial 50 mm AlN substrates grown by physical vapor transport were characterized as received and after 1 μm of homoepitaxial growth by metalorganic chemical vapor deposition. Optical profilometry determined macro-roughness to be sub-nm while atomic force microscopy reveals consistent step edges and 0.1 nm micro-roughness, despite observation of sporadic 100–400 nm wide, ∼1 nm deep depressions. Sub-bandgap photoluminescence reveals broad spectroscopic signals, which slowly vary spatially across the wafer, corresponding with faint visible coloration. Raman spectroscopy indicates uniform, high crystal quality but shows increased background scattering associated with micrometer-scale features visible in optical microscopy. High-resolution x-ray diffraction validates the crystal quality with median (0002) full-width at half maximum of 17.6 arc sec and x-ray topography identified varying regions with dislocation density from ∼102 cm−2 to ∼mid-105 cm−2. Electron microscopy revealed nano-pipes that may be the origin of the nanoscale depressions and that at least some bright optical features are aluminum platelets with coherent atomic boundaries. After epitaxial growth, surface morphology retained smooth macro- and micro-roughness with clear step edges, demonstrating viability of device-relevant epitaxial layer thicknesses for power devices. Three wafers from one boule were characterized, indicating consistent wafer-to-wafer characteristics, critical for future device commercialization.

DNA-PK-mediated CRTC2 phosphorylation promotes NHEJ and suppresses antitumor immunity via relocation to repair complexes

Long-period wurtzite/zinc-blende GaN polytypes as one-dimensional alloys: Impacts of stacking disorder on electronic structure and optical transitions

The electronic structure of wurtzite/zinc-blende GaN polytypes is investigated by treating the stacking sequences of hexagonal and cubic bilayers as one-dimensional pseudo-binary alloys. Using an advanced atomistic empirical tight-binding scheme that is polytype-transferable, we analyze the impact of stacking disorder, namely short-range order, and internal electric polarization on the bandgap, the carrier localization, and the optical transitions. It is pointed out that simple Ising-type models fail to capture the electronic structure of long-period polytypes due to their inability to account for quantum confinement and polarization-induced Stark effects. We also reveal that clustering of cubic or hexagonal bilayers significantly reduces the bandgap, enhances carrier localization, and decreases the optical transitions, an effect dramatically amplified by the internal polarization fields in the insulating regime. These results suggest that stacking disorder in GaN polytypes is not merely a defect but can be viewed as a potentially tunable degree of freedom, behaving analogously to compositional fluctuations in conventional chemical alloys.

Author Correction: Regulatory T cells in the mouse hypothalamus control immune activation and ameliorate metabolic impairments in high-calorie environments

Creation of depth-confined, shallow nitrogen-vacancy centers in diamond with tunable density

Engineering shallow nitrogen-vacancy (NV) centers in diamond holds the key to unlocking new advances in nanoscale quantum sensing. We find that the creation of near-surface NVs through delta doping during diamond growth allows for tunable control over both NV depth confinement (with a twofold improvement relative to low-energy ion implantation) and NV density, ultimately resulting in highly sensitive single defects and ensembles with coherence limited by NV–NV interactions. Additionally, we demonstrate the utility of our shallow delta-doped NVs by imaging magnetism in few-layer CrSBr, a two-dimensional magnet. We anticipate that the control afforded by near-surface delta doping will enable new developments in NV quantum sensing from nanoscale nuclear magnetic resonance to entanglement-enhanced metrology.

Frontier-orbital modulation of rhodium single-atom catalysts for enhanced hydrogen evolution

Abstract Single-atom catalysts (SACs) are promising for hydrogen evolution due to their maximal atomic utilization and discrete energy levels. Modulating metal-support interactions is key to tailoring their activity and stability, yet achieving precise control and mechanistic insight remains challenging and controversial. Here, we construct a rhodium single-atom catalyst model system, with Rh atoms anchored on a series of MoS x Se 2-x supports (Rh SA -MoS x Se 2-x , 0 ≤ x ≤ 2), enabling gradient modulation of metal-support frontier orbital interactions through systematic tuning the anion composition. The elevated lowest unoccupied molecular orbital (LUMO) of MoS x Se 2-x support narrows the energy gap with the highest occupied molecular orbital (HOMO) of Rh atoms, strengthening metal-support orbital hybridization to enhance stability and further amending the LUMO of Rh atoms to optimize both the hydroxide and hydrogen adsorption for high activity. The apex Rh SA -MoSSe catalyst, with optimal HOMO-LUMO hybridization, achieves favorable hydrogen evolution reaction activity and stability simultaneously. This work offers fundamental insights into the metal-support frontier orbital interaction in SACs and establishes a rational design framework for high activity and stability electrocatalysis.

Sign reversal of twofold angle-dependent magnetoresistance in Pt/Mn4N bilayers

Ferrimagnetic Mn4N thin films with perpendicular magnetic anisotropy show great potential for spintronic applications. In this study, we systematically investigated the angle-dependent magnetoresistance (ADMR) of epitaxial Mn4N thin films and Pt/Mn4N bilayers. In the Pt/Mn4N bilayer, interfacial spin Hall magnetoresistance (SMR) dominates the room-temperature twofold ADMR. With decreasing temperature, the Pt/Mn4N bilayer exhibits a sign reversal of the twofold ADMR due to competition between the anisotropic field-induced magnetoresistance (FIMR) of the Mn4N layer and the interfacial SMR, indicating a transition from interface- to bulk-dominated magnetotransport properties. ADMR measurements on Mn4N films confirm that the anisotropic FIMR contributes a non-negligible twofold component to the ADMR. This work enhances our understanding of the competing magnetotransport mechanisms in Pt/Mn4N bilayers, thereby providing a foundation for spintronics based on antiperovskite nitrides.

Structural basis of metalloid transport by the arsenite efflux pump ArsB

Abstract Bacteria resist toxic arsenite (As III ) in their environments by actively pumping the metalloid out of the cell via efflux pumps such as ArsB. However, the mechanism of extrusion remains poorly understood, which hinders the development of engineered bioremediation strategies. We report high-resolution cryo-EM structures of ArsB from the arsenic-tolerant bacterium Leptospirillum ferriphilum . ArsB adopts an inverted two-fold repeat architecture resembling that of other ion transporter (IT) superfamily proteins. Structures determined in the presence of arsenite and antimonite reveal that the metalloid substrates interact with polar residues at the core of the transmembrane domain primarily via hydrogen bonding. Mutagenesis and in vivo functional assays support these interactions. Our ArsB structures represent an ‘inward-facing’ conformation, where the metalloid-binding site is exposed to the cytoplasm, suitable for metalloid capture. Furthermore, we demonstrate that arsenite resistance conferred by ArsB varies with external pH, supporting that ArsB is a proton (H + )-coupled secondary transporter. Mutagenesis, in vivo functional assays, and pK a estimation imply that conserved aspartate residues near the metalloid-binding site likely mediate the H + -coupling mechanism. Our findings provide structural insights into metalloid recognition and H + /metalloid antiport in ArsB, laying a foundation for further elucidation of the molecular basis of toxic metalloid detoxification in bacteria.

Elastic anisotropy and lattice anharmonicity in hexagonal boron nitride revealed by birefringence-resolved Brillouin light scattering

Hexagonal boron nitride (h-BN) is a foundational van der Waals crystal whose exceptional mechanical anisotropy is pivotal for next-generation electronics and quantum technologies. However, a comprehensive understanding of its full elastic tensor and its temperature evolution, crucial for predictive device design, has remained incomplete. Here, we employ birefringence-resolved Brillouin light scattering to determine the elastic tensor and its temperature evolution in a single c-axis-oriented crystal h-BN. Using a circular polarization configuration, we simultaneously resolve the ordinary and extraordinary beams, which enables unambiguous disentanglement of birefringence-induced acoustic mode splitting. This sample-efficient approach yields three independent elastic constants at room temperature: C33 = 24.5 ± 0.1 GPa, C44 = 13.2 ± 0.9 GPa, and C13 = −3.1 ± 5.7 GPa, revealing the extreme mechanical anisotropy of this layered material. From these constants, the lattice thermal conductivity is estimated to be 21 W m−1 K−1 along the c-axis and 347 W m−1 K−1 within the basal plane, quantitatively reflecting the giant anisotropy in heat transport. Furthermore, temperature-dependent measurements across 65–460 K reveal a linear thermal softening of the out-of-plane elastic constant C33, characterized by a relative coefficient dC33/C33dT ≈ −3 × 10–4 K−1, alongside a concurrent linear increase in phonon linewidth governed by three-phonon scattering. These results provide essential quantitative data on the thermo-elastic properties of h-BN, crucial for the predictive modeling and reliable design of h-BN-based devices under thermal stress.

Enhanced B–N coordinated dynamic boronate chemistry for recyclable thermosets with elevated stability

Assessing and tackling the barocaloric fatigue for applicable solid-state refrigeration

Barocaloric materials with pressure-driven first-order transitions are promising for solid-state refrigeration but often suffer from severe cycling fatigue. Here, we select NH4I as a model material, which exhibits a giant barocaloric effect and is ultrasensitive to pressure. Its barocaloric response is directly assessed under loading-unloading cycles with stress up to 100 MPa, with the adiabatic temperature change (ΔTad) decaying from 15 K to approximately 0.8 K after 100 cycles. In situ x-ray diffraction, Raman spectroscopy, and neutron diffraction concertedly reveal the existence of the residual high-pressure phase even after the first unloading, whose fraction is rapidly increased to 90% at the 100th cycle. A phenomenological model is developed to elucidate this fatigue behavior, and an excellent agreement with experimental data has been achieved. To relieve the intergranular stress and enhance the mobility of grains, we encapsulate the composite of NH4I particles and silicone oil into a 3D-printed polymer shell. Such an architectural tailoring has markedly improved the cyclic stability of the barocaloric effect with ΔTad rising to ∼4.6 K after 100 cycles. Our results establish a fundamental understanding of the barocaloric fatigue behavior and pave a feasible route to applicable barocaloric cooling technology.

Mechanism study of hollow-structured MOFs improving catalytic performance

Metasurface tape for efficient millimeter-wave power transfer via surface-wave propagation

Millimeter-wave technologies are essential for future high-speed wireless communications. However, a fundamental challenge remains in the form of severe free-space path loss, where the power density decreases inversely with the square of the distance r (i.e., ∝r−2) as a spherical dependence. To overcome this limitation, we propose a flexible metasurface (MS) tape that is designed to guide electromagnetic energy as surface waves. Unlike conventional free-space propagation, this engineered MS confines the field to a subwavelength interface, thereby altering the power decay law to a circular dependence (i.e., ∝r−1). We numerically and experimentally, for the first time, demonstrate this concept using a periodic grounded patch array fabricated on a flexible substrate and operated at approximately 100 GHz. The measurement results show that the MS tape significantly increases the transmitted power, yielding an average rate of improvement of approximately 40 per meter in received power relative to the free-space baseline in our measurement geometry (e.g., a 29-dB increase at 2 m). This increase is realized over a broad bandwidth from 95 to 105 GHz (i.e., approximately 10%), accommodating wideband modulation schemes required for high-data-rate applications. The flexible, lightweight nature of the tape allows it to be easily installed on diverse surfaces. Our demonstration indicates that the MS tape is a promising platform for extending the effective range of millimeter-wave systems, thus offering a robust solution to the path-loss bottleneck in next-generation wireless networks.

A copper-dependent redox-based hydrogen peroxide perception in plants

Low-loss material for infrared protection of cryogenic quantum applications

The fragile quantum states of low-temperature quantum applications require protection from infrared radiation caused by higher-temperature stages or other sources. In particular, signal lines have to be manufactured to prevent infrared photons entering through dielectric openings while maintaining low microwave loss. We propose a material system that can efficiently block radiation up to the optical range while transmitting photons at low gigahertz frequencies. It is based on the effect that incident photons are strongly scattered when their wavelength is comparable to the size of particles embedded in a weakly absorbing medium (Mie scattering). The goal of this work is to tailor the absorption and transmission spectrum of an non-magnetic epoxy resin containing sapphire spheres by simulating its dependence on the size distribution. Additionally, we fabricate several material compositions, characterize them, as well as other materials, at optical, infrared, and gigahertz frequencies. In the infrared region (stop band), the attenuation of the Mie scattering optimized material is high and comparable to that of other commonly used filter materials. At gigahertz frequencies (passband), the prototype filter exhibits a high transmission at millikelvin temperatures, with an insertion loss of less than 0.4 dB below 10 GHz.