Browse Articles

Unveiling Transition Dipole Moment Anisotropy and Symmetry Breaking Mechanism in Wurtzite Nitride Toward Polarization‐Sensitive Ultraviolet Detection

ABSTRACT Polarization detection in shortwave spectrum using wurtzite wide‐bandgap semiconductors remains challenging due to the isotropic limitations of conventional polar crystal planes. Nonpolar planes offer a promising route, yet the underlying physical mechanism is unclear. Here, we establish a direct correlation between crystallographic polarity and anisotropic photoresponse on nonpolar a‐plane GaN, demonstrating an intrinsic polarization‐sensitive photodetection scheme. Crystal‐field‐induced valence band splitting yields distinct transition dipole moments from heavy‐hole and crystal field split‐off bands to the conduction band minimum, enabling selective absorption for light polarized perpendicular or parallel to the c‐axis. Using the nonpolar plane of GaN, electron transition probability between the heavy‐hole band and conduction band minimum for polarization perpendicular to the c‐axis is selectively enhanced, governing polarization‐angle‐dependent absorption. Our device achieves a high dichroic ratio of 3.79 (318% higher than c‐plane) and an ultrafast response speed of 1.7 µs at 10 V, surpassing conventional polar‐plane architectures and prior polarization‐sensitive detectors. Furthermore, by introducing an oxygen injection layer to strategically break lattice symmetry, anisotropic charge density distribution around oxygen atoms further enhances the dichroic ratio. Exceptional polarization discrimination is validated in single‐pixel polarized imaging and intensity/polarization binary‐channel optical communication encryption. This work establishes a material‐intrinsic paradigm for high‐sensitivity polarization detection, offering new perspectives for multidimensional optoelectronics.

Modeling real life data through an extension of the power Ailamujia distribution and its AR(1) process

Mapping drivers of life expectancy change in Asia from 1990 to 2023

Twist Engineering of Photonic Crystal Cavities for Ultralow‐Threshold Continuous‐Wave WS ₂ Nanolasers at Room Temperature

ABSTRACT Owing to their dangling‐bond‐free surfaces and strong excitonic effects, monolayer transition‐metal dichalcogenides (TMDs) hold promise for ultra‐low‐threshold heterogeneously integrated nanolasers. However, despite extensive demonstrations of TMD‐based nanolasers, further reduction of the lasing threshold is hindered by the challenge of simultaneously achieving an ultra‐small mode volume and an ultra‐high quality (Q) factor in conventional optical cavities. Moreover, the dielectric interfaces of these cavities induce strong dielectric screening and defect‐assisted nonradiative exciton recombination, both of which severely suppress exciton emission in monolayer TMDs. Here, we overcome these fundamental limitations by employing the air modes in a twisted lattice nanocavity. By twisting two finite‐sized hexagonal photonic crystal structures in a single layer of SiN x thin film, we introduce a radial, quasi‐continuous gradient in the air‐filling fraction, thereby forming a radially graded bandgap. This graded bandgap acts as concentric mirrors that tightly confine Bloch modes at the K ‐point, yielding air modes with extreme field confinement in the air and ultra‐high Q factors. By integrating a monolayer WS 2 with the twisted lattice SiN x nanocavity, we experimentally achieve a record‐low lasing threshold of 0.03 W/cm 2 at room temperature. Our work establishes a versatile platform for advanced two‐dimensional (2D) semiconductor light sources.

Decoding the Neural Stages from Action and Object Recognition to Mentalizing

Higher-level action interpretation, such as inferring underlying intentions and predicting future actions, requires the integration of conceptual action information (e.g., “opening”) with semantic knowledge about persons and objects (e.g., “my friend Anna,” “pizza box”). However, how the neural systems for action and object recognition and memory interact with each other to form the basis for inferring higher-level mental states remains unclear. Here we use fMRI-based crossmodal multiple regression representational similarity analysis in human female and male participants to elucidate the processing stages from basic action and object recognition to mentalizing. We show that inferring intentions from observed actions or written sentences involves a modality-general network of lateral and medial frontoparietal and temporal brain regions associated with conceptual action and object representation and mentalizing. The representational profiles in these regions are explained by models capturing different types of conceptual information, revealing distinct but partially overlapping networks for action, object, and mental state representation. There was no strict separation of networks for action, object, and mental state representations, arguing against a sequential bottom–up hierarchy from action and object understanding pathways to the mentalizing network. Rather, left-hemispheric regions, specifically ventrolateral prefrontal, inferior parietal, and anterior lateral occipitotemporal cortex, showed strong representational overlap, pointing toward a core network for making meaning of action–object structures at a conceptual level. We argue that this core network represents a distributional semantic hub between classic networks for action and object understanding and the mentalizing network.

Embryonic exposure to 3,3’,5-triiodo-L-thyronine affects oligodendroglial lineage during neurodevelopment in zebrafish

Rare contagious cancer discovered in wild catfish

Thermally Independent Interfacial Reconstruction for Phase‐Pure <i>n</i> = 1 2D Perovskites With Mixed‐Orientation Surface Architecture

ABSTRACT Two‐dimensional (2D) perovskites are widely employed to enhance the efficiency and stability of perovskite solar cells (PSCs); however, their formation typically relies on thermal annealing, which can degrade the underlying three‐dimensional (3D) perovskite and lead to poorly defined phases. In addition, their intrinsically low out‐of‐plane conductivity imposes a trade‐off between improved stability and efficient charge transport. Here, a thermally independent interfacial reconstruction strategy is reported to enable the phase‐selective formation of phase‐pure n = 1 2D perovskites without thermal activation. This approach suppresses thermally induced degradation and prevents the formation of higher‐n or mixed‐phase intermediates. The resulting 2D perovskite exhibits a mixed‐orientation architecture, comprising domains parallel and tilted relative to the underlying 3D lattice. This structural configuration simultaneously enables effective surface passivation and ion‐blocking while maintaining efficient vertical charge transport, thereby overcoming the stability‐transport trade‐off. As a result, the optimized PSCs achieve a champion efficiency of 26.61% and retain over 98% of their initial performance after 2000 h of continuous maximum power point tracking. In contrast, the control devices exhibit inferior efficiency and accelerated degradation under identical conditions. This work establishes a nonthermal pathway to reconcile stability and charge transport in perovskite optoelectronics.

Integrated assessment of irrigation canal lining and covering impacts on groundwater dynamics in the central Nile Delta, Egypt

Abstract The rehabilitation of irrigation canals may reduce conveyance losses but also diminish recharge to shallow aquifers. One significant source of irrigation canal water loss is seepage. Determining the possible advantages of employing seepage reduction technology and materials requires quantifying the seepage losses in irrigation canals and pinpointing the locations where the seepage loss is most noticeable. However, in numerous regions of the world, seepage from unlined irrigation canals is a major source of groundwater recharge for the shallow aquifers, especially in dry and semi-arid locations like Egypt. The main aim is to assess the effects of canal lining and covering on groundwater recharge and water budget; a secondary aim is to compare numerical seepage estimates with empirical and analytical formulas. In this study, groundwater modeling was implemented utilizing MODFLOW, empirical formulas, and analytical equations were applied. The simulated groundwater level has been compared with the observed groundwater level in observation wells for model calibration. The relationships between Egypt’s central Nile Delta groundwater aquifer system and the irrigation canals in the Gharbia Governorate, considering six operating scenarios: (i) three scenarios of concrete lining of irrigation canals, (ii) three scenarios of covering open canals, (iii) estimate amount of seepage losses from the canals by empirical formulas, analytical equations to verify it with Groundwater Modeling System (GMS) software. The model’s findings demonstrated that the water budget was entirely dependent on the seepage from return flows from irrigated areas, which is the main source of groundwater recharge and supplies roughly 58.4% of the total inflow to the Quaternary aquifer. The seepage from irrigated canals was only a small part of the overall water budget. The leaking from the canal provides around 19.96% of the groundwater replenishment. The percentage of seepage to the canals discharge in the base case (no lining or covering) equaled 2.66%. The concrete lining of irrigation canals (Gharbia and Zefta Directorates canals lining scenario) resulted in a decrease in the aquifer recharge (from 602081 to 23921 m 3 /day). The percentage of seepage to the canals discharge in this scenario reduced from 2.66% to 0.105 %. The water budget analyses associated with converting the open irrigation canals to covering (Gharbia and Zefta directorates canals covering scenario) showed that the aquifer system’s canal leakage accounted for 0.06 m 3 /day. The percentage of seepage to the canals discharge in this scenario reduced from 2.66% to 0.0 %. Also, the results showed that the empirical formula, Molesworth &amp; Yennidunia (0.24 x 10 9 ) m 3 /year along with GMS software (0.22 x 10 9 ) m 3 /year, had good agreement with the results. The outcomes demonstrate that improvements in irrigation conveyance efficiency are accompanied by reductions in groundwater aquifer replenishment. Therefore, canal rehabilitation strategies should be evaluated not only in terms of surface-water conservation but also with respect to their impact on groundwater resources. The outcomes of this research could be helped the decision makers and the stakeholders for achievement of proper water resources management and sustainable development goals (Egypt view 2030) in the central Nile Delta, Ghariba Governorate, Egypt.

The heart has a ‘little brain’ — and it protects against stress

Highly Entangled Bottlebrush Polymer Networks

ABSTRACT Entanglements are topological constraints that govern the dynamic mechanical behavior of polymer networks. Linear polymers inevitably entangle at relatively low molecular weights, whereas bottlebrush polymers—consisting of a long backbone densely grafted with many relatively short side chains—suppress entanglements, enabling solvent‐free networks with tissue‐like softness. Yet, the same steric crowding pre‐strains the backbone and renders such networks brittle. Here, we report highly entangled bottlebrush elastomers that combine extreme softness and toughness. Using short polyethylene glycol side chains, we synthesize high molecular weight bottlebrush polymers (&gt;3 × 10 6 g/mol) that remain amorphous at room temperature. We identify an entanglement threshold of 2.4 × 10 6 g/mol with an entanglement modulus of ∼1.3 kPa, nearly 1000 times lower than that of linear counterparts. While unentangled bottlebrush networks exhibit strain‐stiffening, entangled bottlebrush networks display pronounced strain‐softening followed by delayed stiffening due to entanglement slippage. Despite their low modulus (∼1 kPa), these elastomers stretch up to ∼1800% and show a fatigue threshold of ∼63 J/m 2 , comparable to natural rubber. Their intrinsic fatigue strength—fatigue threshold normalized by modulus—surpasses that of highly entangled linear polymer networks by &gt;40‐fold. These results establish a new class of soft yet tough polymer networks and provide a model system for understanding nonlinear mechanics in architecturally complex polymers.

A novel physics-embedded hybrid learning framework for reliable state-of-charge estimation in Lithium-Ion batteries

Brown bullhead catfish melanoma represents a novel transmissible cancer

Engineered Reverse Growth of Metastable Electron‐Rich Pd Clusters for Enhanced Catalytic/Sonodynamic/Immune Therapy

ABSTRACT Stabilizing metastable electron‐rich metals with atomic dispersion is critical for boosting tumor microenvironment (TME)‐responsive catalysis and sonodynamic therapy (SDT), yet remains challenging. Herein, a “reverse growth” strategy is employed to kinetically trap Pd atoms from bulk Pd nanoparticles (NPs) via sub‐nano CoSe x O y ‐POM assemblies, forming atomically dispersed metastable electron‐rich Pd clusters (Ternary‐Pd). Electron delocalization at the sub‐nanoscale induces electron rearrangement in the entire sub‐nanostructure, thus enabling the acquisition of a novel electronic structure. Interestingly, the Pd clusters exhibit a more negative valence relative to 0‐valent Pd. Specifically, such low‐valent Pd clusters in an atomically dispersed state potently augment TME‐responsive catalytic reactions, exhibiting a 15‐fold enhancement in hydroxyl radical (•OH) generation for catalytic therapy, alongside enhanced hydrogen peroxide (H 2 O 2 )‐responsive oxygen (O 2 ) evolution that mitigates tumor hypoxia. Furthermore, their uniquely enriched electron density at the Pd active sites facilitates electron–hole separation, thereby potentiating SDT efficacy and resulting in a sixfold increase in singlet oxygen ( 1 O 2 ) yield. Abundant and different reactive oxygen species (ROS) induce mitochondrial oxidative stress, activating the caspase‐1/GSDMD‐mediated pyroptosis pathway. Besides, the introduced selenium (Se) doping promotes robust systemic immune responses to inhibit the growth of tumor metastases after oxidative stress.

Ecological and human health risk assessment of heavy metal accumulation in soil and vegetables under 60 years of sewage water irrigation

CRISPR–Cas regulates expression of embedded anti-phage defence systems

Controlled Synthesis and Interfacial Bonding of Hexagonal Diamond/Wurtzite Boron Nitride Covalent Heterostructures

ABSTRACT Heterostructures, mediated by either weak van der Waals (vdW) coupling or chemical bonding at the heterointerface, can compensate for the inherent shortcomings of individual components and achieve exotic properties through their effective integration. The isoelectronic diamond and boron nitride (BN) can present both cubic and wurtzite polymorphs and hence prospectively form diverse heterostructures. However, synthesizing the metastable hexagonal diamond/wurtzite BN (HD/wBN) covalent heterostructures and clarifying the interfacial chemical bonds remain great challenges, despite considerable effort. In this study, we have demonstrated the direct synthesis of high‐quality HD/wBN covalent heterostructures via structural transformation of graphite/hBN vdW heterostructures under high pressure and high temperature. Raman and structural characterizations evidently confirmed the sharp HD/wBN heterointerface with both C─B and C─N bonds, attributed to inversion domain boundaries within the wBN phase. The mapped pressure‐temperature diagram exhibited the confined window required for HD/wBN heterostructures. Our work provides a viable pathway to prepare various covalent heterostructures through synergistic phase transitions and opens new opportunities for exploring their pronounced properties.

Nano-graphitic biochar from pyrolyzed lemon peel as an efficient adsorbent for cationic dye removal from aqueous solutions

Structural basis of the RNA-editing cascade in trypanosome mitochondria

Direction‐Dependent Plasmonic Chiroptical Response With High Asymmetry and Dynamic Tunability

ABSTRACT A direction‐dependent chiroptical response breaks forward‐backward symmetry, introducing an additional degree of freedom beyond conventional circular dichroism (CD) modulation in wavelength, intensity, and handedness. However, most direction‐asymmetric chiroptical materials rely on isotropic films incorporating chiral molecules, showing a relatively weak signal. Here, a plasmonic‐based chiroptical film with a direction‐dependent CD signal is achieved via linear assembly of gold nanospheres (AuNSs) on an elastomeric polymer substrate. This film demonstrates reversal of CD handedness upon changing the light propagation direction from the forward to the backward configuration, accompanied by a significantly enhanced CD intensity from −0.8 to 10.8 deg. This behavior originates from wrinkle‐induced geometrical chirality in the AuNSs assemblies under mechanical stretching, as well as the interplay between the linear dichroism of the AuNSs chains and the strain‐induced linear birefringence of the polymer film. Furthermore, the direction‐dependent response is programmable by varying the mechanical stretching ratio, applied angle, and x ‐/ y ‐orientation, enabling dynamical tuning of signal on/off, magnitude of ellipticity, and reversible handedness. This plasmonic chiroptical film not only provides a strong direction‐dependent CD response, exceeding the performance of most reported systems by 2–3 orders of magnitude, but also possesses multiple degrees of freedom for dynamical chiroptical modulation, presenting a promising platform for circularly‐polarized light‐based information encryption.