Browse Articles

Observation of bandgaps in multilayer silicon nanoribbons

One-dimensional (1D) materials have attracted significant interest due to their unique quantum properties and potential applications in nanoscale devices. Pentagonal silicon nanoribbons (SiNRs), a prototypical 1D material, have been recently reported to host gapless Dirac fermions. However, for practical applications such as logic devices, the realization of a bandgap is highly desirable. In this work, we investigate the electronic structure of multilayer SiNRs grown on Ag(110) using angle-resolved photoemission spectroscopy. Our measurements reveal the emergence of a large bandgap at the Dirac point in these multilayer structures. Tight-binding model analyses suggest that the bandgap arises from the long-range periodicity along the nanoribbon chains. These findings demonstrate that multilayer SiNRs represent a novel phase of elemental silicon and provide a promising platform for engineering bandgaps in 1D materials, with potential applications in quantum and electronic devices.

Evaluation of photobiomodulation therapy for genitourinary syndrome of menopause: A single-center prospective study

Background Genitourinary syndrome of menopause (GSM) is common, and non-hormonal treatment options are needed for women unsuitable for or reluctant to use estrogen therapy. Objective To prospectively evaluate clinical outcomes and clinical improvement rates of photobiomodulation (PBM) for GSM. Methods Twenty-seven postmenopausal women with GSM were enrolled in a prospective study conducted from January 2024 to July 2025. Participants received eight weekly 30-minute sessions of pulsed 660-nm PBM delivered through a stationary silicone vaginal light-guide probe. With the probe attached, target irradiance was 32.38mW/cm² at the probe tip and 13.38mW/cm² at the probe side, corresponding to per-session radiant exposures of 29.14J/cm² at the vaginal fornix and 12.04J/cm² at the vaginal wall. Assessments occurred at baseline (V1), pre-4th session (V2), pre-8th session (V3), and three months post-treatment (V4). The primary outcome was the Vaginal Health Index (VHI). Secondary outcomes included validated questionnaires for lower urinary tract symptoms (LUTS) and sexual function (FSFI). Clinical improvement was defined using established minimal clinically important differences (MCID), minimal detectable change (MDC), and cutoff scores as thresholds. Results The mean age of participants was 62.9 ± 9.7 years. Total VHI scores were significantly higher at all follow-up time points compared to baseline ( p  < 0.05), with all participants reaching the non-atrophic VHI threshold at V4. UDI-6, IIQ-7, OABSS, and several KHQ domains improved significantly ( p  < 0.05) and persisted through the 3-month follow-up. Total FSFI scores improved significantly (p < 0.05), but only 13.3% reached the clinical cutoff (≥26.5) at V4 for functional recovery. No adverse events were observed during the study period. Conclusions Intravaginal 660-nm PBM is a well-tolerated, non-hormonal modality that may improve objective vaginal health and subjective symptoms in GSM. As an integrated therapeutic option, PBM may also improve GSM-related LUTS, suggesting potential relevance for geriatric patients with polypharmacy concerns. Trial registration ClinicalTrials.gov NCT06074120

Inside Back Cover: Differential Adsorption of Functional Groups by Ru/Co Driving Tandem Catalysis: Converting Furanic Molecules into Linear Alcohols (Angew. Chem. Int. Ed. 26/2026)

Microstructural conduction properties of the electrical discharge channels within decay-like degraded FRP rod

Tree-like discharge erosion channels within the fiber-reinforced plastic rod are prominent feature of decay-like degraded composite insulators, and their electrical properties remain insufficiently understood. This study investigates the microstructural electrical conductivity and chemical composition of discharge erosion channels within a decay-like degraded core rod. A cross-sectional sample exposing a discharge channel was prepared using ion beam polishing. The electrical properties were characterized using tunneling atomic force microscopy (TUNA) under different humidity levels, while chemical changes were analyzed via in situ Raman spectroscopy and mapping. The TUNA results revealed a significant current increase within the discharge channel. The estimated channel conductivity is on the order of 3 × 10−8 and 10−4 S/m under low and high humidity, respectively. The porous microstructure within channel likely facilitates capillary condensation of water vapor, creating an ionic conductive path along the fiber direction via the condensed water film. Tree-like microstructure is attributed to partial discharge erosion, while humidity-dependent capillary condensation is proposed to activate ionic conduction, further facilitating discharges. Raman spectroscopy showed a substantial decrease in characteristic peaks of the epoxy resin within the channel, indicating severe polymer decomposition. Critically, the absence of D and G bands suggests that carbonization is unlikely to be the dominant conduction mechanism. Ion chromatography confirmed the presence of nitrate and multiple carboxylic acid anions, and the enhanced conductivity is therefore attributed primarily to dissolved ionic species transporting through capillary-condensed water within the porous channels.

Machine learning-based seasonal SMAP soil moisture retrieval integrating MODIS drought indices: A case study of the Wujiang River Basin

Soil moisture (SM) is a critical regulator of energy and water exchange between the land and atmosphere, yet its accurate retrieval in complex Karst terrains remains challenging due to extreme surface heterogeneity and intricate hydro-thermal coupling. Traditional unified modeling approaches often struggle to capture the seasonally varying, non-linear relationships between remote sensing signals and moisture dynamics in fragmented landscapes. To address these limitations, this study developed a seasonally decoupled machine learning framework, utilizing long-term data from 2019 to 2024, to enhance the spatial representativeness of 9 km SMAP products in the Wujiang River Basin. By integrating 14 MODIS-derived drought indicators with static topographic factors, we constructed differentiated seasonal input sets to account for the “signal decoupling” potentially caused by intense precipitation pulses and phenological shifts. Five algorithms, including RBFNN, SVM, RF, XGBoost, and CatBoost, were systematically evaluated under the Optuna optimization framework. Quantitative results suggest that the CatBoost-based decoupled model achieved an improved balance of accuracy and robustness, with R 2 values reaching 0.537 and 0.572 in spring and autumn, respectively, showing certain advantages over traditional baseline models. Importantly, SHAP-based attribution analysis identifies statistical patterns consistent with a transition in hydrological behaviors, indicating that the model’s decision logic shifts from a ‘topography-driven’ importance in winter to a ‘hydro-thermal-driven’ dominance in summer. This seasonally adaptive approach contributes to mitigating systematic biases in satellite products and provides a potential methodological reference for drought monitoring and water resource management in complex mountainous environments.

Generation of kHz-rate complex-structured liquid targets for relativistic laser–plasma interactions

With the rise of high repetition rate ultra-intense laser systems, there is a need for solid density targets to study relativistic laser–plasma interactions that can operate at the same repetition rate. Flowing liquid targets are attractive because they are self-replenished, debris free, cost effective and easy to use. Liquid targets have been used for high-repetition rate (up to kHz rate) generation of electrons, protons, x rays, and neutrons by our group and elsewhere. In this Letter, we demonstrate a kHz-rate generation of a variety of dynamically shaped complex-structured targets from the interaction of a 1016 W/cm2 focused laser pulse with a submicrometer liquid sheet. The repeatable structured target evolves over microseconds, forming different shapes, such as a hollow channel, a cone, a cone-wire, and a curved surface with a wire. Based on a particle-in-cell simulation, we show that with a cone-wire target, the kHz-rate laser–target interaction could enable the statistical study of warm-dense matter generation that may be useful as a high flux x-ray source. Each stage of the target evolution provides a unique target geometry for ultra-intense laser plasma interaction with numerous potential applications, such as pulsed secondary source generation for high-resolution imaging.

Correction: Exploring scalable assessment methods for terminated trials in ClinicalTrials.gov: A cohort analysis of German and Californian trials

Inside Front Cover: Enhancing Interfacial Charge Transport in Gold Nanoparticle@Polyaniline Hybrids via <i>N</i> ‐Heterocyclic Carbene Linkers (Angew. Chem. Int. Ed. 26/2026)

Accelerated Proton Transfer Channel for Breaking the Bottlenecks of Activity and Stability at Industrial‐Scale Anion Exchange Membrane Water Electrolysis

ABSTRACT Nickel‐iron‐based oxides are promising alkaline oxygen evolution reaction (OER) electrocatalysts, yet their practical implementation in anion exchange membrane (AEM) water electrolysis remains challenging for large‐area membrane‐electrode assembly (MEA) and stability due to complex synthesis and metal leaching issues. Herein, a scalable NiFeV 0.5 O electrocatalyst achieves the single‐batch production of tens of grams and facilitates the fabrication of a 100 cm 2 MEA using the catalyst‐coated membrane (CCM) approach. Using various in situ characterization methods, we track the OER intermediates and identify the dynamic leaching and readsorption of VO x − species. We pioneer an operando rotating ring‐disk electrode (RRDE) methodology with IrO x pH‐sensing probes, which maps the interfacial acidity and demonstrates that these species elevate the local pH by 1.8 units via a hydrogen‐bond‐accelerated proton transfer channel. Experimental and computational analyses reveal that the readsorbed VO x − species are anchored via directional Fe─O─V bonds, suppressing Fe leaching by eight‐fold compared to conventional NiFeO. Notably, when the gram‐scale synthesized NiFeV 0.5 O is applied as an anode catalyst in a practical AEM water electrolyzer, it delivers 3.0 A cm −2 at a cell voltage of 1.88 V and exhibits remarkable stability at 1 A cm −2 over 500 h with a low decay rate of 0.12 mV h −1 .

Stepwise synergistic engineering of phase and domain for excellent energy storage in AgNbO3-based ceramics

AgNbO3-based ceramics are promising lead-free candidates for pulsed-power capacitors, yet their application is hindered by high remanent polarization and large hysteresis. To address this issue, a stepwise synergistic strategy was developed through progressive substitution with Tb3+ and Ta5+ and the addition of MnO2, aiming to tailor phase stability, domain structure, and microstructure. The substitution with Tb3+ (A-site) and Ta5+ (B-site) reduced the tolerance factor and cation polarizability of AgNbO3, stabilizing the antiferroelectric (AFE) phase, suppressing octahedral tilting, and inducing highly dynamic AFE nano-domains. Subsequently, the sintering aid MnO2 was incorporated, which not only reduced defect concentration and refined grain size but also induced pronounced relaxor behavior, facilitating the formation of polar nanoregions, as evidenced by Moiré fringes. This resulted in macroscopically minimized polarization hysteresis and enhanced breakdown strength. Consequently, the 0.10 wt. % MnO2-doped Ag0.97Tb0.01Nb0.8Ta0.2O3 ceramics achieved a high recoverable energy density of 7.02 J/cm3 with an efficiency of 71.59%, demonstrating significant performance merits compared with previous reports. This work demonstrates that stepwise synergy, progressing from independent parameter control to integrated multiscale engineering, provides an effective pathway to simultaneously improve the energy storage density and efficiency in lead-free AFE capacitors.

RGB-based visual encoding of vibration data for gearbox fault diagnosis using U-Net segmentation model

This study presents an innovative approach for diagnosing gearbox gear faults by enabling numerical vibration data analysis using image-based deep learning models. The Gearbox Fault Diagnosis Data set available on Kaggle was used to collect vibration signals from four different sensors (a1, a2, a3, a4). The maximum, minimum, and mean values of these signals were calculated and normalized within the [0–255] range and then mapped to the red, green, and blue (RGB) color channels, respectively. As a result, 500 images of 256 × 256 pixels were generated for each category. Then, these image representations were used to train a pre-trained U-Net deep learning model for segmentation, with only 10 training epochs. The model achieved a classification accuracy of 99.87% and an mean average precision (mAP) score of 99.74%. These high-performance metrics demonstrate that converting non-visual numerical data into RGB images and analyzing them using convolutional neural networks (CNNs) offers significant advantages over commonly used machine learning and text-based deep learning methods.To the best of our knowledge, this is the first study to classify numerical sensor data with such high accuracy by converting it into a visual format. The proposed method not only advances the field of gearbox fault detection and introduces a new paradigm for solving similar signal-based engineering problems in the literature.

Hierarchical Mesoscale Trapping Controls Pathway Selection in Supramolecular Polymerization

ABSTRACT Supramolecular polymerization often proceeds through competing kinetic and thermodynamic pathways, giving rise to pathway complexity that governs the structure and function of supramolecular materials. While pathway selection is typically interpreted in terms of molecular packing, the potential regulatory role of organization beyond the molecular scale remains largely unexplored. Here we demonstrate that hierarchical mesoscale aggregation can control pathway selection during supramolecular polymerization. A donor–acceptor dicyanostilbene derivative forms two primary aggregates that further assemble into mesoscale structures under concentrated conditions. Time‐resolved small‐angle x‐ray scattering combined with spectroscopy reveals that mesoscale clusters transiently trap metastable assemblies, thereby delaying their conversion into thermodynamically favored fibers. Increasing temperature enables escape from this mesoscale trap, directly switching the assembly pathway. These findings identify mesoscale trapping as an emergent kinetic regulatory mechanism in supramolecular polymerization.

Piezoresistive properties of sulfur-doped MDMO-PPV films

The piezoresistive characteristics of a series of sulfur-doped poly[2-methoxy-5-(3′,7′-dimethyloctyloxy)-1,4-phenylenevinylene] (MDMO-PPV) thin films were investigated using indium tin oxide and tungsten as electrodes. The film exhibited optimal piezoresistive performance when the mass ratio of sulfur to the host MDMO-PPV material was 1:10. Within the measurement range of 0–1468 kPa, the calculated piezoresistive coefficient reached approximately 5 Pa−1. This study demonstrates that introducing an appropriate amount of sulfur into MDMO-PPV films can effectively enhance their electrical conductivity, thereby increasing the current density, while preserving the film's elasticity and structural stability. By optimizing the sulfur-to-MDMO-PPV mass ratio to 1:10, the film's performance was significantly improved, achieving an excellent balance between mechanical flexibility and electrical conduction. Consequently, films with this specific doping ratio display excellent overall characteristics compared to their undoped counterparts, indicating promising potential for applications in tactile sensing technologies.

Microstructure—Machinability correlation in heat treated AISI 1040 steel: Comparative analysis of tool life and surface roughness

This study presents an integrated investigation of the machinability of heat treated AISI 1040 steel under annealed, normalized, and oil quenched conditions. The effects of heat treatment parameters, namely austenitizing temperature and soaking time, together with machining parameters including cutting speed, feed rate, and depth of cut, were evaluated in terms of tool life and surface roughness. Experiments were designed using a Taguchi L27 orthogonal array, and the responses were analyzed through analysis of variance (ANOVA), regression modeling, and optimization techniques. The results showed that temperature, cutting speed, and feed rate significantly influenced tool life, whereas feed rate was the most dominant factor affecting surface roughness in all heat treatment conditions. Annealed AISI 1040 steel exhibited the highest tool life and the best overall machinability because of its relatively softer ferrite-pearlite microstructure, while oil quenched specimens showed the lowest tool life due to the formation of hard martensitic phases. Normalized specimens displayed intermediate behavior, indicating a balanced combination of strength and machinability. The developed regression models showed good predictive capability for both tool life and surface roughness within the investigated parameter range. SEM analysis further confirmed that the observed variations in machinability were closely associated with microstructural evolution caused by different heat treatment routes. The study provides useful guidance for selecting suitable heat treatment and machining parameters to improve productivity, tool performance, and surface quality during machining of AISI 1040 steel.

Tuning spectral selectivity in microcavity organic photodetectors via absorption management

Microcavity organic photodetectors (OPDs) utilize optical resonance to achieve wavelength-selective photodetection. Tailoring their spectral response requires understanding the interplay between cavity resonance and intrinsic material absorption. This work systematically controls microcavity resonance through layer thickness modulation and material selection to investigate its influence on spectral response. It demonstrates that employing a thick, strongly absorbing functional layer suppresses wide-angle and multibeam interference effects, thereby inhibiting spectral tunability. Cavity resonance tuning—essential for tailored spectral response—is only achievable by adjusting the cavity length via thickness control of a weakly absorbing functional layer, which facilitates interference between the two reflective electrodes. These results highlight the critical role of absorption management in microcavity OPD design and establish a systematic framework for optimizing spectral response through balanced cavity engineering and absorption control.

Correction: The KrasG12D;Trp53fl/fl murine model of undifferentiated pleomorphic sarcoma is macrophage dense, lymphocyte poor, and resistant to immune checkpoint blockade

Correction to “Electron Transfer Enhanced by a Minimal Energetic Driving Force at the Organic‐Semiconductor Interface”

Defect characterization of amorphous selenium-doped Ga2O3 grown by radio frequency sputtering

Amorphous Ga2O3 thin films doped with selenium (Se) were grown by radio frequency magnetron sputtering to investigate deep-level traps via deep-level transient spectroscopy (DLTS). All samples exhibited good p+–n junction rectification, and DLTS measurements revealed distinct trap states influenced by Se incorporation and sputtering power. The undoped Ga2O3 sample exhibits two hole traps (H1: 0.61 eV, H2: 1.24 eV), while Se doping introduced an electron trap (E1: ∼0.54 eV) associated with oxygen-deficient centers (analogous to VO in β-Ga2O3 crystal lattice) as well as the hole traps (H2: 1.23–1.28 eV; and H3: 1.50 eV) associated with Ga-deficient sites (analogous to VGa in β-Ga2O3 crystal lattice). The resistivity of the samples decreases with Se doping, indicating the formation of donor-like electronic states associated with Se-induced modification of Ga-deficient local environments, analogous to SeGa antisite behavior in β-Ga2O3. These results provide insight into defect control in amorphous Ga2O3 and highlight Se doping as a viable approach for tailoring its electronic properties for oxide electronic and optoelectronic applications.

Case-control study of risk factors for abscess development following hepatitis B vaccination in children in Timor-Leste, 2024

Background Hepatitis B vaccination is essential for preventing chronic hepatitis B infection and its long-term complications. In 2024, a high proportion of reported adverse events following immunization (AEFI) in Timor-Leste involved injection-site abscesses among infants who received the hepatitis B birth dose. This study aimed to explore potential factors associated with abscess formation to inform improvements in immunization practices. Methods We conducted a retrospective matched case-control study in public health facilities across 10 municipalities in Timor-Leste. Cases were infants aged &lt;12 months with a clinically confirmed injection-site abscess occurring within 14 days after receiving the hepatitis B birth dose in 2024. Each case was matched 1:1 with a control by vaccination facility, approximate vaccination date, infant age group, and sex. Data on recipient characteristics, provider practices, vaccine handling, and cold chain management were collected through caregiver interviews, review of clinical and vaccination records, and facility assessments. Matched bivariate associations were evaluated using the exact McNemar test. Results None of the examined variables showed statistically significant associations with injection-site abscess formation; confidence intervals were extremely wide, reflecting the small sample size (12 pairs) and the very small number of discordant pairs (≤4 for all comparisons). Findings should therefore be interpreted as descriptive and hypothesis-generating only. Conclusions This exploratory matched case-control study did not identify any statistically significant risk factors for injection-site abscesses following hepatitis B birth-dose vaccination. Due to the very small sample size, inferential estimates were highly unstable; therefore, the findings should be interpreted as descriptive and hypothesis-generating rather than confirmatory. Despite these limitations, strengthening safe injection practices, appropriate multidose vial management, and adverse events following immunization (AEFI) surveillance systems remains critical. Larger prospective studies are needed to reliably investigate potential determinants of abscess formation.

Dynamic Covalent Radical Recombination for the Assembly of Tuneable Responsive Porous Organic Cages

ABSTRACT The construction of discrete organic cages via radical recombination offers a powerful yet underexplored route toward stimuli ‐responsive, C─C‐linked molecular architectures. Here, we introduce aryldicyanomethyl radical dynamic covalent chemistry as a general strategy for the controlled assembly of porous organic cages. Systematic variation of a single substituent governs both radical and σ‐bond stability as well as the resulting cage geometry, enabling precise, substituent‐dependent control over cage topology and responsiveness. A thiophenoxy‐substituted monomer S selectively affords a discrete Tri 2 dimer in 99% yield, whereas the N ‐methylaniline‐substituted analogue N forms the tetrahedral Tri 4 tetramer in 83% yield. N 4 possesses permanent porosity and pronounced selectivity for CO 2 and H 2 over CH 4 and N 2 , as confirmed by gas sorption experiments, arising from narrow pore apertures and strong host–guest interactions. Both cages display reversible mechano‐ and thermochromic behaviour. Moreover, the combination of a highly dynamic bond formation process with three‐dimensional preorganisation of the cage enables efficient self‐healing, which is markedly accelerated upon exposure to THF vapour. Collectively, these results establish radical recombination as an unexplored dynamic covalent motif for the synthesis of responsive organic cage architectures, enabling substituent‐dependent fine‐tuning of topology, stability, and material function through simple substituent modification.