Browse Articles

Minimal ATP‐Independent N ₂ ‐Reducing Systems Defined by L‐Cluster‐Bound Nitrogenase Assembly Platforms

ABSTRACT The Mo‐nitrogenase, which consists of a reductase component (NifH) and a catalytic component (NifDK), catalyzes ATP‐dependent reduction of N 2 to NH 3 at its active‐site M‐cluster ([( R ‐homocitrate)MoFe 7 S 9 C]). A complex metallocofactor, the M‐cluster is assembled through NifB‐mediated formation of the intermediate L‐cluster ([Fe 8 S 9 C]), followed by L‐to‐M cluster maturation on NifEN. Here, we show that the L‐cluster intrinsically endows the assembly proteins NifB and NifEN with N 2 ‐reducing activity. Such a function is strictly dependent on the L‐cluster, as NifB acquires N 2 ‐reducing capability only after conversion of the precursor K‐cluster (2x[Fe 4 S 4 ]) to an L‐cluster. Both L‐cluster‐bound NifB (NifB L ) and NifEN (NifEN L ) catalyze ATP‐independent N 2 reduction in vitro when supplied with a chemical reductant or photoexcited quantum dots. Moreover, these L‐cluster‐containing proteins support in vivo N 2 ‐fixation in NifH‐deficient E. coli strains, where the low‐potential ferredoxin YfhL serves as an essential physiological electron donor. The intrinsic reactivity of the L‐cluster toward N 2 supports an evolutionary model in which primordial nitrogenase was a simpler, one‐component, NifEN L ‐like enzyme that preceded the modern, high‐efficiency two‐component system; whereas the shared L‐cluster topology found in ancient nondiazotrophic enzymes like methyl‐CoM reductase and methylthio‐alkane reductase further implies that the L‐cluster may represent an evolutionary link among nitrogen, carbon, and sulfur biogeochemical cycles.

Cultural landscape clustering and zoning of traditional rural settlements

Single-cell whole-genome sequencing reveals convergent evolution in Burkitt lymphoma

Dual Polyamide Thin‐Film Composite Membrane With Multiscale Hetero‐Channels and Mosaic Charge Architecture for Boosting Ion Transport and Osmotic Energy Conversion

ABSTRACT Asymmetric ion‐selective membranes show promise for efficient osmotic energy harvesting. Most current asymmetric membranes adopt a bipolar structure to mitigate concentration polarization. However, this approach usually increases transport resistance and compromises ion selectivity. To address these, we rationally designed a dual polyamide thin‐film composite (dPA TFC) membrane via sequential interfacial polymerization (IP). The membrane is composed of two distinct polyamide (PA) layers in situ formed on a macroporous substrate. Through a surfactant‐assisted IP process, an ultrathin inner PA layer with a uniform and negatively charged 3D pore structure was obtained, delivering both high ion selectivity and permeability. Subsequently, a loose outer PA layer featuring a mosaic charge architecture was constructed using protonated porphyrin as a building block. This layer promotes significant unidirectional ion transport and effectively suppresses concentration polarization, while maintaining a high cation selectivity of 0.962. Additionally, the membrane exhibits photo‐responsive behavior, enabling photo‐enhanced osmotic energy conversion and antibacterial activity. As a result, the dPA TFC membrane achieves a high osmotic power density of 13.2 W m −2 under light irradiation. This work provides a design paradigm that overcomes the conventional permeability‐selectivity trade‐off while simultaneously balancing ion concentration polarization suppression with high selectivity, thereby advancing the development of osmotic energy conversion systems.

Resource management for blockchain enhanced federated learning in wireless edge networks

Breaking the activity-selectivity trade-off in Fenton-like catalysis by d-orbital modulation of single-atom sites within a nano-island-like structure

Abstract Direct electron transfer (ETP) during peroxymonosulfate (PMS) activation enables selective, matrix-resistant organic contaminants oxidation, yet its precise control over competing radical pathways remains elusive. Here we report a nano-island-like single-atom catalyst- carbon nitride islands immobilize cobalt single atoms on reduced graphene oxide (CoN 3 C/rGO)- that leverages an island-sea architecture to direct PMS activation toward ETP. Experimental and density functional theory (DFT) analyses show an rGO induced elevation of the Co d -band center and a sharpened d z2 orbital near the Fermi level, promoting directional hybridization with PMS p orbitals and suppressing antibonding occupation. Consequently, CoN 3 C/rGO/PMS degrade bisphenol A (BPA) completely within 5 min, with ~94% contribution from ETP. Furthermore, catalytic membrane coatings enable stable 100 h continuous operation in diverse real water matrices with minimal Co leaching. Our results demonstrate a design principle-orbital-level modulation via island-sea architectures to reconcile activity and selectivity in Fenton-like systems and advance translating practical water treatment technologies based on single-atom electronic control.

Engineering Plasmon‐Semiconductor Coupling in Spatially Ordered Supraparticles for Boosted Photocatalytic Hydrogen Evolution

ABSTRACT Organizing distinct nanocomponents into spatially ordered architectures offers a powerful strategy to regulate light‐matter interactions and enhance photocatalytic efficiency, yet remains largely underexplored. Herein, we report the bottom‐up construction of colloidal supraparticles (SPs) comprising photocatalytic CdS‐based and plasmonic Au nanoparticles (NPs), forming spatially ordered hybrid superstructures with tunable Au NP size and compositional ratios. The optimized CdSe@CdS‐Au SPs achieve a hydrogen evolution rate of 160 mmol h −1 g −1 under visible light, representing a significant enhancement over the mixture of the same components and outperforming previously reported similar NP‐based systems. Ultrafast spectroscopic analyses combined with finite element simulations reveal that spatial confinement facilitates plasmon‐mediated interactions between Au and CdSe@CdS NPs, leading to enhanced plasmonic local electric fields and efficient plasmon‐induced resonance energy transfer from Au to the semiconductor domains. These photophysical advantages collectively account for the markedly improved photocatalytic activity. This study demonstrates nanoscale spatial engineering as a versatile strategy for tailoring hybrid architectures toward high‐efficiency solar‐to‐chemical energy conversion.

Tamm plasmonic-based elliptical anisotropic photonic crystals with multifunctional optical features

Divergent regional responses of soil moisture-air temperature coupling under future climate scenarios

Abstract Climate models project that hotspot regions where soil moisture (SM) influences air temperature (T) will shift and strengthen, affecting droughts and heatwaves, yet the mechanisms driving these changes remain uncertain. Here, we use Coupled Model Intercomparison Project Phase 6 output and find divergent regional responses in SM–T coupling to different future emission scenarios during boreal summer. Under the low-end SSP1-2.6 scenario, SM–T coupling expands across all historical hotspots, while under the high-end SSP5-8.5 scenario, warming produces a latitudinal contrast, where SM–T coupling weakens and contracts at low-to-mid latitudes of the Northern Hemisphere but strengthens at higher latitudes. Coupling also strengthens in the humid tropics south of the equator, where disproportionate evaporation increases offset precipitation gains and depletes soil moisture. These shifts are driven by dynamic and thermodynamic changes modulating the atmospheric and land segments of SM–T coupling. Additionally, the influence of the poleward expansion of the Hadley cells, more pronounced under SSP5-8.5, further pushes SM control on surface energy partitioning northward. Together, these divergent responses reveal a nuanced, scenario-dependent future for SM–T coupling.

Rational Design of a {InCu ₆ } Heterometallic Oxo Cluster for Superior Proton Conduction: Mechanistic Insights and Humidity Gradient‐Based Power Generation

ABSTRACT This study employs a template‐directed assembly strategy to synthesize the first In 3+ /Cu 2+ heterometallic oxo cluster, {InCu 6 } . {InCu 6 } costabilized by l ‐(+)‐tartaric and acetic acids, features a central InO 6 octahedron surrounded by six Cu 2+ ions. Benchmarked against structurally analogous heterometallic oxo clusters, {InCu 6 } demonstrates superior proton conductivity of 7.95 × 10 −2 S cm −1 at 30°C and 90% relative humidity (RH). DFT calculations indicate that the introduction of In 3+ significantly reduces the energy barrier for proton detachment from the oxygen atoms in {InCu 6 } , thus elucidating the kinetic mechanism by which In 3+ /Cu 2+ synergy enhances the conduction efficiency. To translate this molecular performance into a functional device for humidity gradient‐based power generators (HGPGs), a novel cationic polymer ( PVA‐CTPP + Br − ) was designed and synthesized as the matrix to form a uniform PVA‐CTPP + ‐{InCu 6 } composite film. The resulting planar generator demonstrated stable performance, delivering an output of 0.63 V and 14.3 µA cm −2 at 92% RH and room temperature.

Enhanced optimization of photovoltaic units EVCSs and BESS integration in radial distribution networks using a hybrid sine–cosine gorilla search algorithm

Layer-number-parity-dependent abnormal magnetic ordering in few-layer CrI3 on N-face AlN substrate

Effect of 3D-printed co-culture design of mesenchymal stem cells and human umbilical vein endothelial cells on tubular formation

Abstract Functional vascularization remains a major challenge in engineered tissues. Multi-material 3D bioprinting enables precise spatial patterning of different cell types, offering new opportunities to design engineered microenvironments that support vascular self-assembly. Here, we compared three bioprinted co-culture configurations of human umbilical vein endothelial cells (HUVEC) and bone marrow–derived mesenchymal stem cells (BMSC) using a fibrin-gelatin bioink: (i) co-printed within the same filament, (ii) printed in adjacent but distinct filaments, and (iii) cultured in paracrine mode without direct contact. Viability, metabolic activity, and endothelial network formation were evaluated over 14 days. While all designs maintained high viability and metabolic activity, only configurations incorporating BMSC supported extensive and stable CD31-positive endothelial networks. Quantitative 3D surface analysis revealed significantly greater tubular surface area in both co-printed and adjacent filament constructs versus paracrine-only conditions. Notably, HUVEC network formation in adjacent filament constructs was comparable to that achieved by co-printing, indicating that initial physical co-localization within the same filament is not required, provided cells are within migratory distance. These findings establish a practical design principle for bioprinted vascularized constructs: physical proximity, rather than filament co-localization, is sufficient to promote endothelial self-organization, thereby expanding design flexibility for multi-material bioprinting strategies.

Genomic and ecological drivers of parallel arid adaptation in tree grapes (Vitaceae)

Unexpected Spontaneous Photochemical Formation of Hydrogen Peroxide in Water Microdroplets on Silicate Mineral Surfaces

ABSTRACT Hydrogen peroxide (H 2 O 2 ) is a vital reactive oxygen species with significant roles in atmospheric and environmental chemistry. While its spontaneous generation in water microdroplets has gained attention, the abiotic pathways for its formation are still not fully understood. In this study, we demonstrate the rapid and spontaneous photochemical generation of H 2 O 2 in pure water microdroplets on quartz surfaces under anoxic conditions. We show that H 2 O 2 is efficiently formed through multiple pathways, including direct water photooxidation at the solid–water interface and, more significantly, reactions between water and quartz surface‐bound peroxy radicals (≡Si–O–O·). The observed H 2 O 2 production rate reached 2.5 × 10 11 molecules cm − 2 s − 1 in microdroplets on quartz, exceeding that of bulk water photolysis by five orders of magnitude. This process occurs across various natural silicate minerals, suggesting that photochemical reactions in water microdroplets on silicate surfaces may represent a significant yet previously overlooked source of H 2 O 2 in Earth's environment. Additionally, the solid–liquid interface reactions demonstrated in this study may offer a novel approach for the industrial‐scale synthesis of H 2 O 2 , providing an efficient and sustainable alternative to traditional methods.

A novel thermal image based cold object detection and classification using machine learning algorithms

Intermolecular interactions optimization in weakly solvating ether solvents for wide-temperature Na metal batteries

Mechanically Activated Luminescence in Polyurethanes Incorporating Calixarene Mechanophores

ABSTRACT The conformational properties of cone calix[4]arenes are exploited to develop the first example of a calixarene‐based mechanoluminophore. By functionalizing the distal positions at the upper rim of a calix[4]arene with pyrene moieties, we produce a macrocycle incorporating two 1,6‐bis(phenylethynyl)pyrene fluorophores. The flexibility of the calix[4]arene scaffold facilitates the formation of intramolecular ground‐state excimers involving the pyrene units, as evidenced by 1 H NMR and fluorescence spectroscopy. Incorporating the calixarene mechanoluminophore into linear polyurethanes yields uniform films that exhibit the characteristic pyrene excimer emission. When these films are stretched, either manually or using a universal tensile tester, a fluorescence shift from green–yellow to blue is observed under irradiation with UV light. Such fluorescence change is reversible and repeatable over numerous stress and release cycles. We attribute this behavior to conformational changes in the calix[4]arene triggered by mechanical force, and in particular to the temporary dissociation of the intramolecular pyrene excimers into pyrene monomers. Thus, the flexible calix[4]arene scaffold enables the reversible separation of the two fluorophores while preserving their spatial proximity. We propose that this design concept can provide general guidelines for creating supramolecular mechanophores free of intermolecular aggregation effects.

Field strength and frequency-dependent effects of pulsed electric fields on soilborne nematodes, pathogens, and weeds

Abstract Pulsed electric field (PEF) technology is a non-chemical approach with potential to control soilborne agricultural pests. PEF disrupts cellular membranes through short, high-energy electrical pulses. Treatment efficacy depends on electric field strength, pulse frequency, and applicator design. Field strength reflects the intensity of the electric field driving electroporation, whereas energy density represents the cumulative dose delivered to the system, and pulse frequency determines how that dose is distributed over time. In this study, two soil-applied PEF applicators, vertical pins (VP) and parallel plates (PP), were evaluated for suppression of weeds, plant-parasitic nematodes, and soilborne pathogens. Numerical simulations showed that the PP configuration generated a more uniform electric field distribution than the VP design. Consistent with these predictions, the PP applicator provided greater biological suppression across target organisms. Cyperus esculentus biomass declined progressively with increasing energy density and was significantly reduced at ≥100 J cm −3 . The PP applicator also reduced Meloidogyne chitwoodi second-stage juveniles by up to 100% at 25 J cm −3 and pulse frequencies above 60 Hz. Densities of Pratylenchus neglectus and M. chitwoodi were reduced by more than 98% at 400 V mm −1 . Weed responses were species dependent: biomass of C. esculentus and Digitaria sanguinalis declined at 100–200 J cm −3 , whereas Echinochloa crus-galli required higher energy inputs for control. Soilborne pathogens also differed in susceptibility, with Phytophthora cinnamomi and P. plurivora reduced by 94% at moderate field strengths (100–200 V mm −1 ), while Verticillium dahliae was suppressed by up to 97% at 200–400 V mm −1 and 80 Hz. Overall, nematodes and soilborne pathogens were suppressed at substantially lower energy densities (~25 J cm −3 ) than weed propagules, which generally required ≥100–200 J cm −3 for effective biomass suppression. These results demonstrate that PEF can effectively suppress multiple soilborne pests. Additionally, the results highlight the importance of applicator design and electrical parameters in determining treatment efficacy, supporting the potential of PEF as a scalable and sustainable soil disinfestation technology.

5′ leader defects drive persistent HIV-1 viremia on long-term ART

Abstract Traces of HIV-1 RNA can persist in plasma despite long-term suppressive antiretroviral therapy (ART). Some individuals develop nonsuppressible viremia (NSV), characterized by detectable HIV-1 RNA that raises concerns for virological failure, pathogenesis, and transmission. The sources of NSV remain poorly defined, in part due to limited tools to characterize plasma HIV-1 RNA. Both infectious and defective proviruses, including those with defects in the 5′ Leader (5′L), can contribute to NSV, but their relative contributions have not been quantified. Here we show that in over 50 participants, plasma viremia is markedly driven by highly clonal HIV-1 RNA populations carrying defects in the 5′L. Across individuals, dominant clones with 5′L defects clustered around the major splice donor (MSD) accounted for the vast majority of circulating HIV-1 RNA. To enable rapid, scalable profiling, we developed CLAWS (Capturing 5′ Leader Anomalies Without Sequencing), a digital PCR assay that distinguishes intact from defective 5′L RNA. CLAWS recapitulated sequencing-based estimates and detected low-abundance defective RNA early after ART initiation, revealing that defective genomes emerge early and become predominant during long-term therapy. These findings identify 5′L-defective genomes as the predominant driver of NSV and establish CLAWS as a practical tool for monitoring viremia in clinical and cure-related settings.