Browse Articles

The phenology of the European flat oyster (Ostrea edulis) and its environmental drivers

Abstract The European flat oyster ( Ostrea edulis ) is an ecosystem engineer that structures reef habitats and is a major focus of restoration efforts across Europe, yet its biological rhythms in its habitat remain unknown. These rhythms synchronize physiology with environmental cycles, indicating ecological adaptation. Here, we investigated behavioral, physiological, and molecular rhythms in O. edulis , as well as their environmental drivers. Using high-resolution valvometry, we monitored valve activity and shell growth over 540-days in the German Bight (Helgoland), along with environmental variables such as photoperiod, temperature, underwater sound, and food availability. Monthly gene expression profiling of clock-related genes was also performed. O. edulis displayed coordinated daily, tidal, lunar, semilunar, and annual rhythms, mainly driven by photoperiod and temperature. This integrative chronobiological approach reveals a multiple rhythm system in O. edulis , highlighting both adaptive capacity and vulnerability to anthropogenic pressures, and providing key indicators for the conservation and restoration of oyster reef habitats.

Model-free predictive control for PMSM based on a nonlinear autoregressive exogenous model and an adaptive recursive least squares algorithm

This paper proposes a novel nonlinear autoregressive with exogenous input-based adaptive recursive least squares model-free predictive control (NARX-ARLS-MFPC) strategy for permanent magnet synchronous motor (PMSM) drives. The core challenge addressed is the performance degradation of conventional model predictive control (MPC) under inevitable motor parameter mismatches. The proposed method integrates the NARX model with an ARLS algorithm featuring a variable forgetting factor to dynamically track system changes. Comprehensive simulation studies validate the superior robustness of the strategy. Under significant inductance and flux linkage mismatches, the proposed method reduces current total harmonic distortion (THD) by 28.3% and 12.3% compared to conventional finite-control-set model predictive control (FCS-MPC) and a baseline control method, respectively. It maintains stable performance under moderate sensor noise with appropriate tuning. During load transients combined with resistance and inductance mismatches, it achieves THD reductions of 24.1% and 15.7% versus the two benchmark methods, respectively. Statistical analysis under parameter perturbations confirms its overall superior performance across key dynamic and steady-state metrics. The results demonstrate that the synergistic integration of the nonlinear model and adaptive identification effectively suppresses current harmonics caused by model inaccuracies while enhancing dynamic performance.

Fabrication of fully suspended Hall crosses in GaAs/AlGaAs heterostructures and scaling of submicron AuGeNi ohmic contacts

In this work, we demonstrate the fabrication of a device to investigate electron–phonon coupling in quantum systems on a suspended island, together with a systematic study of submicrometer AuGeNi ohmic contacts required for its implementation. The island is separated from the substrate but electrically connected to the rest of the surrounding structure with four micrometer- or submicrometer-sized ohmic contacts and metal leads. The contacts are characterized on planar test structures and subsequently integrated into suspended devices. Square contacts with areas ranging from 1600 down to 0.0056 μm2 are fabricated in both surface-deposited and recessed geometries contacting a 20 nm GaAs quantum well, 50 nm below the surface, in a 120 nm thick GaAs/AlGaAs heterostructure. Two-point DC current–voltage (I–V) measurements at 77 and 3.8 K show that double annealing the contacts reliably produces ohmic behavior across all footprint sizes. Analysis of the area dependence of resistance reveals a critical area of (0.80 ± 0.01) μm2, corresponding to a transfer length (0.894 ± 0.013) μm and specific contact resistivities in the range of (0.5–2.3) × 10−6 Ω cm2, demonstrating that robust ohmic performance can be maintained at deep submicrometer dimensions. We further examine electrochemical etching effects in GaAs/AlGaAs and develop a fabrication pathway that avoids electrochemical damage, enabling the realization of a fully suspended Hall cross isolated from the phonon bath. This provides a platform for future studies of electron–phonon interactions and many-body-localization effects in semiconductor heterostructures.

Dual-channel graph neural network for dental 3D point cloud model segmentation

Chiral Phosphoric Acid-Catalyzed Asymmetric Hydrogenolysis of C–O Bonds

Experimental emergence of conventions in human dyads

Conventions can be defined as arbitrary and self-sustaining practices that emerge in a population and facilitate solving coordination problems. A recent study traced the formation of simple conventions in captive baboons in a touch-screen-based color-matching ‘game’. We replicated this task with human pairs under different conditions (with/without visual access to the partner’s screen; with/without prior information on the task structure) to assess their effects on the formation and stability of conventions. We found that more information delayed the formation of conventions (arbitrary rankings of colors that determined choices in any given color pairing). Analysis of self-reported strategies did not reveal a clear effect of condition on levels of elicited strategic behavior. Interestingly, pairs maintained their conventions even when given visual access to their partner’s screen, despite the availability of an alternative, potentially simpler, cognitive strategy. In a follow-up variant of the task that paired up experienced subjects with a naïve partner, conventions emerged faster but did not replicate the color hierarchy convention of the experienced player, demonstrating the transmission of “know-how” but not “know-what” information. We discuss the implications of our results for understanding the cognitive mechanisms necessary to support the formation, maintenance, and transmission of conventions.

A topologically engineered honeycomb-like (2-0)-2 piezoceramic composite ultrasonic transducer with superior sensitivity

Piezoelectric ultrasonic transducers (PUTs) are widely utilized across a variety of technological fields; however, further advancement in ultrasonic transducer performance faces fundamental limitations. Herein, we report a brand-new (2-0)-2 piezoelectric ceramic composite (PCC) for enhancing sensitivity, featuring a topologically engineered honeycomb-like piezoceramic plate architecture [termed the (2-0) phase] uniformly embedded within the epoxy resin matrix (2-phase). This unprecedented novel structure effectively decreases the relative permittivity, acoustic impedance, and stiffness of the ceramic composite, while preserving the intrinsic main piezoelectricity and restraining the transverse piezoelectric effect. The resulting PCC shows a hydrostatic figure of merit (HFOM) dhgh of 3784.1 × 10−15 m2/N, representing a 312.3% improvement compared to that of the conventional 2-2 type PCC. Experimental results validate the performance enhancements of the (2-0)-2 PCC-based PUT, including a −6 dB transmitting bandwidth of 130 kHz, a higher transmitting voltage response and receiving voltage sensitivity, and an output voltage that is 46.4% higher than that of the conventional 2-2 composite transducer under identical excitation conditions. This proposed design strategy offers valuable guidance for the development and optimization of next-generation piezocomposite materials and high-sensitivity ultrasonic transducers.

VARUNA: verifiable adaptive resilient unified framework against byzantine attacks in federated learning-based IDS

Abstract The integration of Federated Learning (FL)-based Intrusion Detection Systems (IDS) in Internet of Things (IoT) faces significant challenges due to the statistical heterogeneity of distributed datasets. The IDS datasets are often highly imbalanced and biased toward majority classes, leading to degraded IDS performance. To mitigate this, Generative Adversarial Network (GAN) models are deployed at central server nodes to balance datasets and maintain system heterogeneity. However, the security of FL systems remains vulnerable to adversarial attacks, which can manipulate model updates and compromise system integrity. This research introduces the Multi-Agent GAN Network Exploitation Tactic (MAGNET), leveraging actor-critic-based reinforcement learning to manipulate GAN models. MAGNET distributes these compromised models to selected clients, enabling the simulation of complex adaptive attacks. Additionally, we propose the Coordinated Model Attack Network System (CMANS), which disrupts global model convergence through malicious gradient manipulation techniques such as Gaussian noise injection, gradient scaling, and inversion. These attacks significantly impact the performance of FL environments applied to IDS datasets. We present a robust Verifiable Adaptive Resilient Unified (VARUNA) Framework for trustworthy IDS in resilient FL systems to address these vulnerabilities. This approach employs an adaptive trust score to detect and eliminate Byzantine activities, effectively neutralizing over 99% of malicious clients in scalable FL environments. VARUNA achieves consistent error rate reductions of up to 9.4% across all attack classes, restoring model performance from an average error increase of 0.03 under CMANS and MAGNET attacks back to the pre-attack baseline across all four aggregation methods (FedAvg, Krum, Trimmed Mean, and Median). Our solution ensures a secure, efficient, and trustworthy IDS, outperforming undefended FL baselines by a statistically significant margin on all three evaluated benchmark IDS datasets.

Trimethylammonium-Substituted Amphiphilic Pillar[ <i>n</i> ]arene Channels for Selective Water Permeation

In vivo changes in zebrafish anesthetic sensitivity in response to the loss of kif5Aa are associated with the alteration of mitochondrial motility

Anesthetic and sedative drugs are small compounds known to bind to hundreds of proteins. One intriguing binding partner of propofol is the motor domain of a neuronal mitochondrial transport kinesin, kif5A. Here, we used zebrafish wild type (WT) and kif5Aa knockout (KO) larval behavioral assays to assess anesthetic sensitivity and combined that with zebrafish primary neuronal cell culture to probe for alterations in mitochondrial motility. We found that the loss of kif5Aa increases behavioral sensitivity to propofol and etomidate, with etomidate hypersensitivity greater than propofol. In contrast, kif5Aa KO animals were resistant to the behavioral effects of dexmedetomidine. Finally, WT and kif5Aa KO larvae responded similarly to the behavioral effects of ketamine. Propofol inhibited the anterograde motility of mitochondria in WT zebrafish neurons, while etomidate inhibited mitochondrial motility in both anterograde and retrograde directions; neither drug altered mitochondrial motility in the kif5Aa knockout (KO) neurons. In contrast, dexmedetomidine enhanced retrograde mitochondrial motility in both WT and kif5Aa KO animals. Finally, ketamine had little significant effect on mitochondrial motility in either mutant or WT animals. These data demonstrate that each anesthetic/sedative drug affects the motor protein machinery uniquely and is associated with unique changes in behavior. Understanding how different anesthetic compounds alter neuron motor proteins will be important in defining how anesthetics alter neuronal signaling and energetic dynamics.

Ultra-long-life zinc-iodine batteries enabled by efficient conversion of iodine on high-spin Fe single-atom sites embedded into 3D porous graphene

The practical application of aqueous zinc-iodine batteries as promising low-cost and large-scale energy storage devices is still hindered by the polyiodide shuttle effect and sluggish iodine redox kinetics. Herein, we designed highly dispersed Fe atom coordinated by planar N dopants with axial Cl ligand on three-dimensional porous graphene nanosheets (3DGNFe-Cl) as the cathode host to promote iodine conversion for efficient zinc-iodine batteries, which was developed through a simple impregnation of ammonia-treated 3D porous graphene with FeCl3 followed by calcination. The 3D porous graphene nanosheets provide abundant sites to accommodate iodine and ensure iodine with high conductivity, while the atomically dispersed, high-spin FeN4 moieties induced by the axial Cl ligand serve as efficient catalytic centers. These centers enhance the direct conversion of the I−/I2 redox reaction with less formation of polyiodide via an additional σ-bonding interaction between the Fe 3d and I 5p orbitals, effectively solving the critical issue of the polyiodide shuttle. As a result, the zinc-iodine battery with 3DGNFe-Cl containing I2 loading of 50% as cathode delivers a high specific capacity of 0.47 mAh cm−2 at 1 mA cm−2 and an exceptional long-term cycling stability with retaining 100% of its capacity after 85 000 cycles at 10 mA cm−2, exceeding all previously reported results. Moreover, a corresponding single pouch cell achieves an areal capacity of 3 mAh cm−2. This work demonstrates an effective strategy of developing high-performance zinc-iodine batteries through the modulation of the spin-state of Fe atom sites to improve iodine conversion.

A predictive maintenance model for sustainable urban transit: the Riyadh Metro case study

Directed Evolution of Nonheme Fe Enzymes for Enantioselective and Regiodivergent 1,3- and 1,4-Nitrogen Migration: Biocatalytic Asymmetric Synthesis of Noncanonical α- and β-Amino Acids

Electrochemical hydrogen pumps powered by <i>in situ</i> waste heat recovery and enhanced by 3D MXene-CNT carriers

Electrochemical hydrogen pump (EHP) technology is promising for purifying industrial by-product hydrogen (IBH), but low cost and high efficiency are key for practical use. This study recovers low-temperature waste heat from IBH to power the EHP and constructs a high-surface-area support [3D MXene-carbon nanotube (CNT)] to boost the reaction rate. The wrinkled structure inhibits MXene stacking, increases specific surface area to 213.5 m2 g−1, and CNTs form an efficient conductive network. Applied to both EHP and a thermally regenerative battery (TRB), Pt-3D MXene-CNT exhibits a large electrochemically active area and low overpotential. At 1 V, the EHP achieves a current density of 1.12 A cm−2 (93.1% higher than Pt/C) and low decay over 80 h. In the TRB, 3D MXene-CNT-S delivers a peak power density of 86.6 W m−2 and 89.6% capacity retention after 30 cycles. A coupled TRB-driven EHP system is demonstrated, showing a higher H2 production rate and longer operation time. This work provides theoretical guidance for efficient, low-cost IBH purification.

Integrative characterization of the HER2-TLS maturation axis reveals immune heterogeneity and prognostic subtypes in gastric cancer

Dynamic Coordination-Enabled Metal-Dependent Configurational Switching in a Covalent Organic Framework

A Universal Nucleoside‐to‐Nucleoside‐5′‐Triphosphate Enzyme Cascade Driven by Polyphosphate

ABSTRACT Nucleoside‐5′‐triphosphates (NTPs) are important building blocks for nucleic acids, but the efficiency of their chemical synthesis is limited by the low yield of the final 5′‐triphosphorylation reaction. Here, we present an enzymatic cascade reaction involving just two enzymes that enable nucleosides‐to‐NTPs conversion for all canonical rNTPs and dNTPs. The cascade is used in a single one‐pot operation driven by cost‐efficient sodium polyphosphate (polyP). The broad‐spectrum deoxynucleoside kinase (Dm‐dNK) from Drosophila melanogaster converts nucleosides into nucleoside‐5′‐monophosphates (NMPs) using ATP. The polyphosphate kinase family 2, class III (EbPPK) from an Erysipelotrichaceae bacterium simultaneously recycles ATP required by Dm‐dNK and converts the NMPs to NTPs in a polyP‐dependent reaction. Importantly, only trace amounts of catalytic ATP (0.0001 equivalents or less) are required. In addition to canonical NTPs, the cascade can generate ribose‐ and base‐modified NTP analogues. This is demonstrated through the synthesis of a set of eleven modified nucleotides, including the four 2′‐fluoro‐2′‐dNTPs and nucleotides with 2,6‐diaminopurine as the nucleobase. Production of an essential component for mRNA therapeutics, N 1‐methyl‐ΨTP (m 1 ΨTP), is demonstrated on a milligram scale.

Multijunction photovoltaic fibers with record efficiency for energy-harvesting textiles

Multijunction (MJ) photovoltaics offer the highest demonstrated solar power conversion efficiencies but have not been previously integrated into deformable textile architectures. Here, we demonstrate III–V MJ photovoltaic fibers (PVFs) that combine record PV performance with mechanical compliance and textile compatibility. Chip-scale III–V MJ PV dies are surface-mounted onto flexible fiber substrates using a scalable fabrication process compatible with textile integration. The resulting fibers achieve total-device-area power conversion efficiencies of 19.5% under AM1.5 illumination and 13.0% under AM0, representing the highest efficiencies reported to date for fiber-integrated PV devices. Based on a device coverage fraction along the fiber established by bending-fatigue constraints, a fully populated MJ PVF is projected to achieve a total fiber-area efficiency of 14.7% under AM1.5 illumination. Thermal cycling between −55 and +85 °C produces no measurable changes in PV performance metrics, indicating initial thermo-mechanical stability following integration. Using embroidery-based conductive interconnects, MJ PVFs are integrated into fabrics and shown to directly power light-emitting fibers, demonstrating energy-harvesting electronic textiles. These results establish MJ PVFs as a pathway toward lightweight, conformal PV systems for terrestrial and space applications.

Seasonality of acute kidney injury incidence in Japanese outpatients

Abstract Acute kidney injury (AKI) is a clinically important condition associated with adverse outcomes. While community-acquired AKI is common, its seasonal patterns remain poorly understood, particularly in outpatient settings. This study aimed to examine the seasonality and community-acquired AKI in Japan. Of 4,401,387 individuals with at least 1 month of data in the Japanese health insurance claims database between August 2016 and July 2018, 4,282,805 were included in the analysis as outpatients. The monthly incidence of community-acquired AKI was evaluated using the incidence rate ratio (IRR) calculated by generalized estimating equations. We constructed multivariable models adjusted for sex, age, comorbidities and medications. There were 20,634 new-onset community-acquired AKI cases. The frequency of new-onset community-acquired AKI gradually increased from June to July, with the highest adjusted IRR in July (1.19 [95% confidence intervals: 1.11–1.27]). Subgroup analyses showed that IRRs for community-acquired AKI were consistently higher in July than in February across all categories. Notably, a significant interaction was observed between seasonality and age ( P  = 0.029), with the highest IRR observed in the youngest age group (&lt; 20 years). These results suggest the potential relevance of seasonal and environmental factors in AKI prevention in outpatient settings.

Patchy Membrane-Directed Multiphase Complex Coacervation