Browse Articles

Multi-mechanism synergistic regulation of charge dynamics in epoxy composites via plasma-assisted polydopamine interface engineering

The accumulation and migration of space charges severely limit the application of polymer insulation in high-voltage direct current systems. This study investigates epoxy resin composites modified with polydopamine-functionalized boron nitride nanosheets (PDA@BNNS), where a two-step process involving plasma hydroxylation and subsequent polydopamine coating was employed to enhance the filler-matrix interface. The composites were characterized using pulsed electro-acoustic measurements, direct current (DC) conductivity tests, surface potential decay, and broadband dielectric spectroscopy. Results show that the 3 wt. % PDA@BNNS composite exhibits optimal performance, suppressing space charge accumulation and reducing the stored charge amount by approximately 36% at 20 kV/mm compared to pure epoxy. The effective charge injection barrier at 20 kV/mm increases from 1.12 eV (pure epoxy) to 1.35 eV (3 wt. % composite), and the conduction activation energy rises to 0.70 eV. The introduction of deep traps not only modifies the trap-limited space charge-limited current but also fundamentally alters the bulk conduction mechanism. To further elucidate this, the temperature-dependent conductivity was analyzed. Charge transport transitions to a three-dimensional variable-range hopping mechanism dominated by deep traps. A multi-mechanism synergistic model is proposed, encompassing barrier enhancement, deep trapping, potential quantum confinement, field homogenization, and relaxation optimization. This interface engineering strategy provides an effective approach for developing high-performance DC insulation materials.

GREM1 acts in leptin receptor-expressing skeletal cells to mediate peri-implant fibrosis

A framework for objectively comparing competing invasion percolation models based on highly-resolved image data

Predicting gas migration in water-saturated porous media (a multiphase flow problem) is essential for applications such as carbon dioxide sequestration, hydrogen storage, and groundwater remediation. This process is challenging because gas migration can occur either as continuous or discontinuous flow, depending on the flow rate and the properties of the porous medium. Numerous variations of Invasion-Percolation (IP) models can simulate multiphase flow across different scales (from pore-scale to macroscopic), but the literature suggests that IP models are best suited for the discontinuous gas flow regime; other regimes have not been systematically evaluated. Here, we present a quantitative framework for comparing and ranking macroscopic IP models against high-resolution experimental data from transitional and continuous gas flow regimes. The analysis employs a diffused Jaccard coefficient to measure the similarity between model outputs and time-series two-dimensional images from gas injection experiments in water-saturated sand. To represent pore-scale heterogeneity, we run each model version on several random realizations of the initial invasion threshold field. The Jaccard coefficient was averaged over all realizations per model version to evaluate performance and calibrate model parameters. Depending on the application domain, some macroscopic IP model versions are suitable for these previously unexplored flow regimes. We also find that heterogeneity in the initial invasion threshold field strongly influences model performance. The observed applicability of IP models in these regimes can substantially reduce computational costs compared to continuum-based models for applications such as carbon dioxide storage and groundwater protection, although their ultimate use depends on the specific research question being addressed. The proposed comparison framework is not limited to gas–water systems in porous media but generalizes to any modelling situation accompanied by spatially and temporally resolved data.

Pyro-Phototronic Effect enhanced position-sensitive detection observed in ZnO nanowires/Ag2S quantum dots heterojunction

The development of position-sensitive detectors (PSDs) with high sensitivity and ultrafast response is essential for advanced applications like dynamic tracking and artificial vision. However, limited light absorption and inefficient carrier separation are two major factors constraining the performance of PSDs. Here, we use a pyro-phototronic coupling strategy to address these challenges and develop a high-sensitivity, ultrafast, broadband PSD based on ZnO nanowires/Ag2S quantum dots heterojunction. The pyro-phototronic effect provides an enhanced electric field to facilitate carrier separation and transport, and thus the photoresponse enhancement factor of the heterojunction PSD reached 332.4%. Correspondingly, the heterojunction PSD exhibits a high sensitivity of 230.6 mV/mm, an ultrafast response time of 9.4 μs, and a broad detection range from 405 to 980 nm. We propose a pyroelectric-field-driven carrier diffusion model to elucidate the underlying physical mechanism for the performance enhancement. This work not only provides a useful strategy for developing high-sensitivity, fast-response optoelectronic devices but also holds significant potential for applications in dynamic tracking and real-time sensing technologies.

Single-photon emission from two-dimensional perovskites channeled through low-energy edge states

Abstract Two-dimensional perovskites, an emerging family of van der Waals materials with an innate quantum-well structure, exhibit remarkable optical characteristics and compositional tunability. However, their potential as a source for quantum emitters remains unexplored. Here, we investigate low-energy edge states unique to two-dimensional perovskites using comprehensive photoluminescence imaging and spectroscopy, to further leverage them towards uncovering quantum emitters. In contrast to above-bandgap excitation, spatially localized single-photon emitters are realized through sub-bandgap energy excitation at the edges in exfoliated single crystals. Specifically, the sub-bandgap excitation facilitates efficient access to deeply confined states within the bandgap, as charge carriers can channel through low-energy edge states while inhibiting competing processes. Furthermore, we demonstrate single-photon emitters from artificially created edges via strain as well as from two-dimensional perovskites with different quantum-well thicknesses. Our findings provide promising opportunities in the development of two-dimensional quantum emitters, where two-dimensional perovskites may provide added functionalities with versatility in material design, fabrication, and scalability.

Relationship between household attributes and contact patterns in urban and rural South Africa

Households play a crucial role in the propagation of infectious diseases due to the frequent and prolonged interactions that typically occur between their members. Recent studies have emphasized the need to include socioeconomic variables in epidemic models to account for the heterogeneity induced by human behavior. While sub-Saharan Africa suffers the highest burden of infectious disease diffusion, few studies have investigated the mixing patterns in the countries and their relation with social indicators. This work analyzes household contact matrices measured with wearable proximity sensors in a rural and an urban village in South Africa. Leveraging a rich data collection describing additional individual and household attributes, we investigate how the household contact matrix varies according to the household type (whether it is composed only of a familiar nucleus or by a larger group), the gender of its head (the primary decision-maker), the rural or urban context, and the season in which it was measured. We show the household type and the gender of its head induce differences in the interaction patterns between household members, particularly regarding child caregiving, suggesting they are relevant attributes to include in epidemic modeling.

Orbital current induced angular-dependent magnetoresistance in Mn4N/Ti bilayers

The detection of orbital currents in ferromagnetic/light-metal bilayer systems has remained a challenging task in recent studies. In this work, Mn4N epitaxial thin films and Mn4N/Ti bilayers with perpendicular magnetic anisotropy were deposited on MgO (001) substrates using facing-target magnetron sputtering. When the magnetic field is rotated in the plane perpendicular to the direction of the current, the Mn4N/Ti bilayers exhibit a negative angular-dependent magnetoresistance compared to the Mn4N thin films. Moreover, this phenomenon is suppressed when a Pt interlayer is introduced. We attribute this phenomenon to the orbital current generated via the orbital Hall effect and the orbital Rashba effect at the interface, which interacts with the magnetization orientation to modulate the electrical resistance. These results provide circumstantial evidence that implicates the generation of orbital currents in Ti and their potential role in the interfacial magnetotransport phenomena.

Comparative genome analysis provides a foundation for defining salvinorin A biosynthesis in Salvia divinorum

Abstract The synthesis of salvinorin A by Salvia divinorum is of considerable interest for developing pain relief, anti-opioid addiction and antidepressant medications, but progress has been compromised by limited access to plant material and the complexity of the biosynthetic pathway. Initially using S. splendens , a closely related species, the first steps in the biosynthetic pathway have been elucidated. Here, by preparing a genome sequence for S. divinorum , we are able to undertake comparative genomic analyses with closely related species that do not produce salvinorin A. We establish the genetic basis for additional activities in salvinorin A biosynthesis involving cytochrome P450 and methyl-transferase enzymes. Our genome-based, microevolutionary approach provides insight into how specialized furanoclerodanes of immense pharmacological importance evolved. These results lay a clear path for identification of the remaining steps in the biosynthetic pathway which would allow synthetic production for the development of new therapeutics.

A smoothing and bootstrap-based framework for early outbreak detection

Timely detection of infectious disease outbreaks is critical for effective public health response. The effective reproduction number ( R t ) is a key metric that captures transmission dynamics and signals the potential onset of outbreaks when it rises above 1. However, day-of-the-week and public holiday effects, along with random fluctuations in reported cases, can distort R t estimates and reduce their usefulness for real-time surveillance. In this study, we present an R t -based outbreak detection framework that integrates calendar-aware smoothing with bootstrap inference to quantify the uncertainty of smoothed R t estimates. Using daily COVID-19 case data from Singapore, we evaluate several smoothing approaches—including a working-day moving average (MAH) that adjusts for public holidays—and compare the performance of the proposed method with established outbreak detection algorithms such as Early Aberration Reporting System (EARS), Bayesian-based detection methods (EpiEstim) and logistic regression–based approaches. In our framework, calendar-aware smoothing is not a generic pre-processing choice but a necessary, model-agnostic step that produces R t inputs with reduced calendar artefacts. This makes subsequent inference and testing on R t both more stable and more interpretable. Our results show that smoothing, particularly with MAH, improves the stability of R t estimates and enables more reliable outbreak detection. The proposed method consistently demonstrates superior timeliness across observed and simulated outbreaks, while maintaining desired false positive rates. Simulation studies further confirm its robustness under varying sample sizes and case volumes, highlighting advantages over other methods. In conclusion, the proposed method offers a simple, interpretable, and theoretically grounded framework for early outbreak detection. Its consistent performance across real and simulated data suggests it may be broadly applicable to other infectious diseases with similar transmission dynamics.

Suppressed electron–phonon coupling in Ag-doped CsPbBr3 for high-performance photodetectors

Charge transport in metal halide perovskites is strongly limited by electron–phonon coupling (EPC) and trap-assisted recombination, which together hinder carrier mobility and device efficiency. Therefore, precise control of EPC strength is crucial for realizing high-performance optoelectronic devices, such as photodetectors. Here, we demonstrate a strategy to overcome these limitations by suppressing Fröhlich electron–phonon coupling in CsPbBr3 nanocrystals through strategic Ag-doping. Low temperature photoluminescence data reveal a dramatic suppression of the Fröhlich interaction, with the EPC strength narrowing from 85.1 ± 8.2 to 45.3 ± 6.1 meV, accompanied by a reduced activation energy upon Ag incorporation. This suppression of phonon-mediated dissipation is further validated by ultrafast transient absorption studies, which reveals significantly prolonged ground-state bleach recovery and extended carrier lifetimes. Consequently, Ag-doped photodetectors exhibit a record detectivity of ∼8.4 × 1013 Jones, an on/off ratio of ∼107, and a fourfold enhancement in the responsivity (0.64 A/W). The near-unity photocurrent behavior with intensity (exponent of 0.98), along with emission behavior, confirms Ag-doping passivates defects and improves carrier extraction. These results establish a strong correlation between lattice engineering and macroscopic device physics, offering a scalable route to high-performance, phonon-managed perovskite optoelectronics.

Hydrogen bonding mediated electron donor-acceptor acceptor catalysis in hydrosulfonylation and sulfonyl dehydrogenation of olefins

The Women’s Wellness with Type 2 Diabetes Programme: Feasibility of an online peer support and goal-setting intervention for midlife women

Objective The Women’s Wellness with Type 2 Diabetes Programme (WWDP) is a complex intervention, encouraging positive lifestyle behaviours to enhance wellness outcomes. A previous feasibility study found the original WWDP had a good effect signal and was acceptable to women but had challenges with national scalability. In response, the programme was revised (WWDP+). This study evaluated the feasibility of delivering the WWDP+ and its evaluation procedures and assessed physical and psychosocial outcomes in midlife women to inform the design of a future randomised controlled trial. Methods A single arm, pre- and post-intervention design were conducted. Women living with type 2 diabetes and aged between 45–65 years were recruited via a social media campaign using purposive sampling targeting individuals who had previously expressed interest in type 2 diabetes research. Alongside recruitment and completion rates, clinical and behavioural study outcomes were assessed at baseline, 3 months and 6 months post baseline. Individualised goals were set at week 3 and assessed at 12-week. Analysis comprised descriptive statistics, Wilcoxon’s signed-rank and paired t tests. Results Thirty-four women (mean age = 55.4) from diverse backgrounds participated. Feasibility targets were met: 77% recruitment of eligible women, 88% 12-week completion, and data completeness of 82% at 3 months and 79% at 6 months. Post-intervention diabetes distress decreased by 1.52 points (p < 0.001), self-reported HbA1c decreased by 13 mmol/mol (p < 0.02) and BMI by 0.6 kg/m 2 (p < 0.049). Menopausal symptoms declined by 13 points on the Greene scale (p < 0.001). Improvements were observed in diabetes self-efficacy (+7.4 points, p < 0.001), general health (+27.5 points, p < 0.01), sleep disturbance (–6.2 points, p < 0.002), and confidence in making dietary choices (+1.1 points, p < 0.02). Goal attainment scores indicated that 68% of participants achieved or exceeded their expectations. Conclusions This feasibility study suggests that the WWDP+ is acceptable and feasible for midlife women with type 2 diabetes. The findings will directly inform the design, sample size, and recruitment strategies of a fully powered randomised controlled trial to evaluate WWDP+ effectiveness. Trial registration ISRCTN: ISRCTN93338547. https://doi.org/10.1186/ISRCTN93338547

Impact of substrate resistivity on the high-power and long-lifetime conduction characteristics of intrinsically triggered 4H-SiC PCSS

The conduction efficiency and reliability of photoconductive semiconductor switches (PCSSs) are strongly influenced by the resistivity of semi-insulating 4H-SiC substrates. In this work, PCSSs fabricated on four 4H-SiC substrates with resistivities ranging from 2.59 × 1011 to >1 × 1012 Ω cm were evaluated under intrinsic excitation (355 nm) and high-voltage, high-repetition operation. All devices exhibit similar optical saturation behavior and comparable switching speed, indicating consistent optical absorption and intrinsic response. In contrast, pronounced differences in conduction stability and degradation behavior emerge under high electric fields and high repetition rates. Under saturated excitation, the low-resistivity device achieves a voltage-conversion efficiency of 99.3%. It also delivers a stable 10 MW peak output for 35 min at 500 Hz, corresponding to more than 106 switching cycles. In comparison, devices fabricated on higher-resistivity substrates exhibit accelerated output decay and more severe electrode degradation. Technology Computer Aided Design simulations yield conduction characteristics consistent with the experimental observations. These results highlight the critical role of substrate resistivity of intrinsically triggered 4H-SiC PCSSs and provide guidance for material selection in high-voltage fast-pulse switching applications.

Engineering ligands for theophylline riboswitches expands its regulatory dynamic range in prokaryotic and eukaryotic systems

Numerical simulation of a hot-air cleaning fan for the combine harvester

This study aimed to improve the separation efficiency of damp crops by developing a hot-air cleaning fan. First, the aerodynamic performance of two fans with different inlet structures was compared. The results showed a direct correlation between the static pressure and the outlet air velocity. The modified-inlet fan has an outlet average air velocity very close to the original fan of the combine harvester. Hence, the modified- inlet fan model was chosen for further analysis. Subsequent evaluations were conducted to assess the effects of fan speed, inlet air temperature, and volute temperature on fan performance. Fan speed exhibited a negative correlation with outlet air temperature but a positive correlation with outlet air velocity, at both the upper and lower outlets. Furthermore, both the inlet air temperature and the volute temperature were directly related to the air temperature at these outlets. A Response Surface Methodology (RSM) with three factors at three levels was utilized to optimize fan parameters, identifying fan speed and inlet air temperature as the predominant factors affecting outlet air velocity and temperature, respectively.The optimal set of parameters was determined to be a fan speed of 1445 rpm, an inlet temperature of 85 °C, and a volute temperature of 60 °C. Under these conditions, bench test results indicated the average air velocity and temperature are basically consistent with the theoretical optimal value.

Comparing the phonons and vibrations in carbon allotropes with neutron spectroscopy: Microdiamond, few-layer graphene, and amorphous fibers

Powder-averaged inelastic neutron spectroscopy was performed in order to compare the phonons of microdiamond, few-layer graphene, and amorphous carbon fibers at room temperature. Both acoustic and optical phonons were observed in the crystalline allotropes. We present average group velocities, phonon densities of states, and heat capacities relevant to intrinsic thermal transport. High-temperature measurements were performed to evaluate whether quasiparticle broadening from phonon–phonon scattering could be detected. The glassy carbon form in the fibers exhibits pronounced spectral broadening and an enhanced low-energy density of states beyond the Debye prediction. Methods for estimating thermal conductivity using inelastic neutron data as input to the phonon-gas model are discussed. We highlight opportunities and challenges for employing higher-resolution methods to directly determine phonon lifetimes.

RNA functional modulation by Mitoxantrone via RNA structural ensemble repartitioning

The effect of dumping syndrome severity on health-related quality of life among bariatric surgery patients in Saudi Arabia

Dumping syndrome is a postoperative complication of bariatric surgery; it is classified into early and late dumping syndrome depending on the time of the symptoms. This study aimed to assess the health-related quality of life among adult patients in Saudi Arabia experiencing varied severity of dumping syndrome after a sleeve gastrectomy or a Roux-en-Y gastric bypass procedure. This cross-sectional study was conducted using a validated health-related quality of life questionnaire administered online to adults (≥17 years old), who had undergone bariatric surgery in Saudi Arabia. The study recruited 237 eligible adults; 142 (59.9%) of them had severe dumping syndrome. The mean physical health component summary score was 45.01 (SD = 8.42) and the mean mental health component summary score was 38.89 (SD = 9.74). Individuals with severe dumping syndrome had significantly lower (p = 0.041) physical and mental health component summary scores compared to individuals with moderate severity dumping syndrome. Higher household income was associated with higher physical and mental health summary scores. Participants who underwent gastric bypass surgery had significantly lower physical health summary scores compared to those who underwent sleeve gastrectomy. Dumping syndrome is more prevalent in women than men. The most common symptoms are a desire to lie down (79.3%) and nausea (37.9%). Patients with severe late dumping syndrome were more inclined to seek help from various healthcare providers, highlighting potential gaps in effective management strategies. These findings suggest current management approaches for severe late dumping syndrome may be insufficient, prompting the need for developing standardized treatment protocols and increasing awareness among healthcare providers. Future research should focus on evaluating the effectiveness of different therapeutic interventions and exploring strategies to improve patient outcomes and access to specialized care.

Anomalously low thermal conductivity in a light-element cubic semiconductor: Cubic BeB2

Cubic semiconductors composed of light elements, such as diamond and boron nitride, typically exhibit exceptionally high thermal conductivity. Recently, a cubic phase of BeB2 was predicted to possess superior electronic properties, including high carrier mobility. Here, using the Boltzmann transport equation with force constants derived from first-principles calculations, we reveal that cubic BeB2 displays an anomalously low thermal conductivity, reduced by approximately 98.4% compared with diamond at 300 K. This dramatic suppression originates from its unique structural feature, namely, the Be atom resides at the center of an octahedral cage formed by boron atoms, exhibiting a rattling-like motion. The resulting low-frequency optical phonon modes anti-overlap with acoustic modes, leading to reduced group velocities and enhanced scattering of acoustic phonons. In particular, optical-mode-mediated three-phonon scattering channels, such as TA+TA→O and TA+O→O, dominate the scattering processes, substantially shortening phonon lifetimes. The combination of weakened group velocities and intensified scattering leads to severely suppressed thermal conductivity. These low-frequency optical modes correspond to vibrations of Be atoms within the boron cages, as confirmed by their large mean-squared displacements. Our findings suggest that incorporating weakly bonded interstitial impurities could provide an effective strategy for tuning the thermal conductivity of semiconductors.

Reinforced biotubes as readily available and regenerative vascular grafts