Browse Articles

A Synergistic Triphase Electrolyte Design Enables 4.6 V LiCoO ₂ Quasi‐Solid‐State Batteries with Ultra‐Long Cycling

ABSTRACT Pushing LiCoO 2 to ≥4.5 V causes coupled degradation: electrolyte oxidation and cathode structural collapse, especially at high rates. Here, we propose a triphase synergistic gel‐electrolyte to tackle both failure modes. The system, constructed by in situ thermal polymerization, integrates an ether‐rich crosslinked polymer network, surface‐activated AlN fillers with Lewis acid–base sites, and a fluorinated electrolyte. This design regulates Li + transport, confines free solvent molecules, and reconstructs the solvation sheath. More importantly, it induces a uniform, inorganic‐rich cathode–electrolyte interphase at an early stage. Consequently, LiCoO 2 ‐based quasi‐solid‐state cells deliver exceptional stability: over 1000 cycles at 4.6 V and 5 C with an average decay of only ∼0.03% per cycle, and 85.98% capacity retention after 500 cycles in practical Si–C||LiCoO 2 pouch cells. Operando EIS‐DRT analysis reveals that the triphase electrolyte substantially suppresses the growth and fluctuation of interphase‐related polarization at high voltage, making the remaining impedance evolution more governed by transport/contact processes. This work demonstrates that decoupling interfacial and structural degradation through a synergistic electrolyte design is key to realizing high‐voltage, high‐power, long‐life quasi‐solid‐state batteries.

Spin Engineering of Ni‐Based High‐Entropy Oxide Cocatalyst: Synchronously Optimizing Intermediate Adsorption and Charge Carrier Separation for Photocatalytic Hydrogen Evolution

ABSTRACT High‐entropy materials (HEMs), as an emerging multicomponent system, exhibit significant potential in green solar energy conversion owing to their continuously tunable electronic structures. Nevertheless, the complex local chemical environments in HEMs induce significant differences in intermediate adsorption/desorption at metal active sites and complicate photoexcited electron transfer. Herein, we propose a strategy of incorporating heterogeneous transition metal Zn into a high‐entropy oxide (HEO) lattice to precisely tune the spin state of Ni 2+ . Since the spin‐state transition of Ni 2+ does not involve electron transfer from t 2g to e g orbitals, but rather only involves electron redistribution within e g manifold, its electronic structure is particularly sensitive to lattice distortion‐induced variations in crystal‐field strength, thereby enabling selective regulation of Ni 2+ from low‐spin to high‐spin. Field‐dependent magnetization measurements and x‐ray absorption spectroscopy confirm that Zn incorporation effectively modulates the spin state of Ni 2+ . Density functional theory calculations and femtosecond transient absorption spectroscopy reveal that high‐spin Ni 2+ exhibits an upshifted d ‐band center and pronounced spin polarization, which synergistically optimize both *H adsorption and photogenerated charge carrier separation efficiency. Consequently, 0.75%FeCoNi 0.3 MnZn–HEO/Cd 3 (C 3 N 3 S 3 ) 2 (0.75%Ni 0.3 Zn–HEO/CdTMT) exhibits a prominent PHE rate of 47.53 mmol g −1 h −1 . This work opens new paradigms for the rational design of spin‐directed multi‐component HEMs.

Interfacial Structure Modulation Triggering Dual Sites Synergy for Industrial‐Grade Water Electrolysis

ABSTRACT Anion exchange membrane water electrolysis (AEMWE) is recognized as a promising technology for green hydrogen production. The development of high‐performance non‐noble‐metal‐based (NNM) electrocatalysts is crucial for its industrial‐scale deployment. However, in alkaline media, they typically face a critical challenge in simultaneously activating water molecular and optimizing hydrogen species adsorption, resulting in sluggish water dissociation kinetics. Herein, we engineer a NiS/Ni 3 S 2 heterojunction with strong interfacial interaction via a facile cathodic polarization method. Theoretical and experimental analyses reveal a synergistic dual‐site mechanism of hydrogen evolution reaction: Ni sites promote H 2 O adsorption through upshifted d‐band center, serving as the primary water dissociation centers; concurrently, S sites optimize the hydrogen binding energy by accepting interfacial charges, facilitating H* adsorption/desorption. This dual‐site mechanism significantly lowers the energy barrier of the Volmer step. Impressively, in AEMWE tests the resultant NiS/Ni 3 S 2 @W requiring only 1.73 and 1.68 V to reach a current density of 1 A cm −2 at 60°C and 80°C, respectively. Furthermore, it can maintain stable operation for over 1 000 h at 1.5 A cm −2 and exhibits robust tolerance under dynamic fluctuating conditions. This work provides a reliable interface engineering strategy for designing efficient electrocatalysts for industrial‐grade water electrolysis.

Engineering Metal‐Pocket Cooperativity in Single‐Atom COF Nanozymes for Selective Cascade Catalysis

ABSTRACT Nanozymes have emerged as robust and scalable alternatives to natural enzymes, offering high catalytic activity and structural stability. However, reproducing the exquisite selectivity of enzymatic catalysis, particularly their ability to operate with high precision in complex reaction systems, remains a central challenge. Herein, inspired by the heme–pocket architecture and cooperative regulation in cytochrome P450, we report a nanozyme multilevel programming strategy based on a single‐atom covalent organic framework (COF) platform constructed from heme‐like metal–porphyrin nodes and linkers bearing chiral amino‐acid residues, enabling selective editing of metal catalytic centers and enzyme‐mimetic pockets to control catalytic activity, chemoselectivity, and stereochemical outcomes. As a proof of concept, we employ a biomimetic chiral cascade that couples methanol dehydrogenase‐like alcohol oxidation with a chymopapain‑inspired asymmetric aldol reaction to probe and optimize metal–pocket cooperativity within the nanozyme. The programmed MnPor‐Pro‐based nanozyme delivers high product yields, excellent chemo‐ and stereoselectivity, and outstanding recyclability in the cascade reactions, indicating the effectiveness of this strategy. This work provides a rational design insight for engineering highly selective nanozymes capable of addressing complex, multistep transformations, significantly bridging the gap between artificial and natural enzymatic systems.

Local Atom Clusters Drive Supercritical Relaxor State in Lead‐Free Dielectrics for Giant Energy Storage

ABSTRACT Perovskite relaxor ferroelectrics have emerged as the leading capacitive energy‐storage materials in pulsed‐power electronics and integrated energy systems. However, conventional relaxor design strategies encounter a fundamental trade‐off, wherein increasing compositional complexity to suppress hysteresis typically weakens local polar strength, thereby hindering the simultaneous realization of ultrahigh recoverable energy density ( W rec ) and efficiency ( η ). Herein, we demonstrate that sublattice‐hierarchical local atom clustering provides an effective approach to overcoming this limitation. By combining strong A ‐site disorder with Mg/Hf‐rich nanoregions on B ‐site sublattices, we embed atomic clusters within a relaxor ferroelectric matrix to stabilize a supercritical relaxor state. Through neutron total scattering techniques and atomic‐resolution electron microscopy, we reveal that local atom clusters not only enhance lattice distortion to form ultrafine polar nanodomains but, more importantly, strengthen the local random field to enable strong and highly reversible polarization. As a result, the designed lead‐free ceramic achieves an ultrahigh W rec of 17.03 J cm −3 and an excellent η of 93.5%, resulting in a superior figure of merit up to 262. The fast‐discharging capability and robust stability against temperature, frequency, and cycling further evidence its strong application potential. These findings identify local atom clustering as a general and powerful approach for designing high‐performance dielectric ceramic capacitors.

Conformal Thermoreversible Gelatin‐Based Gel for High‐Fidelity Electrophysiological Recording and Acute Peripheral Nerve Interfacing

ABSTRACT Conformal and tissue‐adaptive bioelectronic interfacing remains a challenge for electrophysiological recording and nerve stimulation, particularly on irregular or hair‐covered surfaces where conventional electrodes fail to maintain intimate, low‐impedance contact. Here, we report a thermoreversible gelatin‐based gel that transitions from a flowable precursor to a conformal conductive interface layer upon cooling, enabling both in situ formation on skin and use as a preformed compliant interlayer between metal electrodes and neural tissue. The gel integrates a uniformly dispersed carbon nanotube network with mobile ions from sodium chloride to support coexisting ionic and electronic transport pathways, while the gelatin‐based matrix provides moisture retention and mechanical compliance. It achieves low interface impedance on hairless and hairy skin, outperforming commercial electrocardiogram gels, and electroencephalogram pastes. The gel's versatility is demonstrated across multiple modalities and species, including electrocardiography and acute peripheral nerve stimulation in rats, compound muscle action potential and sensory nerve action potential recordings in rhesus monkeys, and electroencephalography in humans. Beyond these cross‐sectional assessments, repeated short‐term recordings using the gel enable longitudinal evaluation of peripheral nerve functional recovery in nerve injury models. Together, this work establishes a tissue‐adaptive and reconfigurable strategy for achieving stable, low‐impedance bioelectronic interfacing across complex biological environments.

Innovative and Multidisciplinary Research of Materials Science at Fudan University

Extreme Bond Ionicity in Mg─Te Chalcogenides for Ultrathin Low Voltage Selector‐Only Memory beyond the Leakage Scaling Limit

ABSTRACT Conventional ovonic threshold switching (OTS) chalcogenides face a fundamental scaling limit for selector‐only memory (SOM), because aggressive thickness scaling increases leakage current and hinders reliable low voltage operation. Here, this trade‐off can be overcome by exploiting the unique materials characteristics of the Mg─Te chalcogenide system. Guided by the bonding ionicity map and supported by density functional theory calculations, Mg─Te is identified as an optimal telluride material whose highly ionic bonding is associated with deeper trap levels, a large memory window of 1.75 V, and suppressed leakage in 20 nm devices. Structural analyses and multiscale simulations suggest that the spontaneous phase separation in Mg 1 Te 3 forms MgTe‐like ordered nanodomains and Te‐rich amorphous regions, providing structural partitioning that may constrain the effective amorphous switching network and reduce stochastic switching variability. With a thin Hf interlayer, the 5 nm Mg 1 Te 3 device achieves narrow SET/RESET switching uniformity of σ  = 15/28 mV at ± 2.5 V operating voltage, representative 10 ns programming speed, and write endurance exceeding 10 10 cycles in the best‐performing device. These results highlight Mg─Te as a promising basis for highly scaled ultralow voltage SOM through the combined roles of ionic bonding, structural partitioning, and interfacial engineering.

Single‐Cell Metabolic Activity Monitoring With Microcavity Laser Emitting Cytometry

ABSTRACT Single‐cell metabolism analysis is essential for understanding cellular heterogeneity. However, the ability to track it in real time, with high precision and under physiological conditions, remains a formidable challenge. Here, we introduce a microcavity laser‐emitting cytometry for single‐cell metabolism analysis. Single cells and the biocompatible gain medium resazurin were co‐encapsulated into droplets via a microfluidic device. These droplets then flowed into the Fabry‐Pérot (F‐P) cavity, resulting in a 15‐fold reduction in the laser pump energy, effectively alleviating phototoxicity. Capitalizing on cavity‐enhanced light‐matter interactions and ultra‐narrow laser linewidths, subtle changes in resazurin concentration resulting from metabolic activity induced redox reactions within cells were transduced into quantifiable, ultra‐sensitive shifts in the lasing wavelength. This approach achieved a sensitivity of 0.382 nM per 10 pm shift. Hence, our single‐cell laser emitter enabled the quantitative characterization of metabolic kinetics at the single‐cell level, facilitating applications in cytometry for metabolic heterogeneity analysis, cell‐type discrimination, and drug efficacy quantification. This platform enables single‐cell laser emission for cell screening and pharmacological evaluation, advancing research in areas like cancer treatment and drug discovery.

Geometric Complementarity and Electrostatic Fluctuation Control in Dual‐Asymmetric Acceptors for Efficient Organic Solar Cells

ABSTRACT Asymmetric molecular design has emerged as an effective strategy for developing high‐performance acceptors for organic solar cells (OSCs). Here, we introduce a dual‐asymmetric topology strategy, in which the stereochemical configurations of both the central core and terminal groups are co‐engineered. Using this approach, we synthesized an isomeric pair, Th2Cl‐a‐2Cl and Th2Cl‐b‐2Cl and benchmarked them against the singly asymmetric a‐CH‐Th2Cl and Th2Cl‐4Cl. We find that the distinctive steric conformation of Th2Cl‐a‐2Cl promotes a geometrically complementary, interlocked packing motif within the crystal lattice. This not only reinforces the three‐dimensional network connectivity but, more importantly, gives rise to a more uniform local electrostatic environment at the molecular‐skeleton scale. As a result, Th2Cl‐a‐2Cl exhibits weaker and more balanced environment‐induced electrostatic fluctuations along the backbone, which helps reduce local electrostatic perturbations during charge transport. Consequently, PM6:Th2Cl‐a‐2Cl devices deliver a champion PCE of 20.18% with a high fill factor (FF) of 80.88%, while significantly suppressing the non‐radiative recombination loss (Δ E 3 ) to 0.190 eV. These results establish geometric complementarity and electrostatic homogeneity, achieved through topological engineering, as an effective route to improve the efficiency of OSCs.

Pathways to High‐Efficiency Perovskite‐Organic Tandem Solar Cells

ABSTRACT Perovskite‐organic tandem solar cells (POTSCs) have emerged as a promising strategy to transcend the thermodynamic Shockley–Queisser limit of single‐junction devices. This architecture uniquely combines the exceptional tunability of wide‐bandgap (WBG) perovskite front cells with narrow‐bandgap (NBG) organic rear cells. In this review, we systematically examine the critical challenges and advancements in POTSCs. For the WBG perovskite subcells, we focus on composition engineering for precise bandgap tuning, the underlying thermodynamic and kinetic mechanisms of phase segregation, energy loss pathways resulting from non‐radiative recombination, and interface regulation strategies. Regarding the organic subcells, we highlight the necessity of exact bandgap matching and summarize molecular design strategies aimed at developing highly efficient NBG materials. Finally, we discuss the tandem architecture potential for achieving high power conversion efficiencies and synergistic stability. In this synergistic configuration, the WBG perovskite layer acts as a natural UV filter to protect the organic materials from high‐energy photons, while the moisture‐insensitive organic layer provides a barrier to shield the perovskite from water and oxygen erosion. By dissecting these key aspects, this review aims to provide a comprehensive roadmap for propelling POTSC efficiencies beyond the 30% milestone.

Cilia‐Structured Lipiodol Droplets Enable Long‐Term Transarterial Embolization Therapy by Nano‐Interlocking Adhesion

ABSTRACT Transarterial embolization (TAE) offers an effective and minimally invasive therapy for unresectable hepatocellular carcinoma (HCC), one of the most lethal malignancies globally, but being limited by short‐term embolization failure for example recanalization due to weak interfacial adhesion. Herein, we report cilia‐structured lipiodol (CS‐lipiodol) droplets by self‐assembling dual‐asymmetric microparticles with hydrophilic cilia‐structured hemispheres and hydrophobic plain hemispheres at the lipiodol–water interface, enabling long‐term TAE therapy by the cilia‐mediated nano‐interlocking effect. CS‐lipiodol droplets exhibit strong interfacial adhesion and viscoelastic deformability through the nano‐interlocking effect and the Pickering‐like architecture, allowing tight and efficient occlusion across multiple in vitro embolization models. The enhanced interfacial adhesion to vascular cells and adjacent droplets confers long‐term vascular occlusion and approximately three‐fold higher in vivo embolization rates than commercial embolic agents. In the orthotopic rabbit HCC model, purely physical occlusion with CS‐lipiodol droplets induced superior tumor volume reduction. Our study provides a healthcare material platform for long‐term and vascular‐adaptive TAE therapy.

Pressure‐Resilient Electron‐Ion Networks via Multifunctional Carbon Conductive Agents for High‐Rate Solid‐State Batteries

ABSTRACT Silicon‐based all‐solid‐state batteries (ASSBs) promise high safety and energy density, yet their rate capability remains fundamentally constrained by the disruption of continuous electron‐ion transport networks induced by large volume variations. Herein, we introduce a pressure‐resilient electron‐ion network enabled by a molten‐salt‐mediated multifunctional carbon conductive agent featuring a graphene‐like stacked framework with uniformly distributed nanopores. This architecture enables synergistic electron‐ion transport (with electronic and ionic conductivities of 133.26 S cm −1 and 1.89 mS cm −1 ), accommodates large deformation (up to 91.3% strain) without structural failure and retains high elasticity under a compressive strain of 80.6%. Operando expansion and kinetic analysis reveal that the elastic network dynamically adapts to silicon volume changes, preserving interfacial integrity and continuous transport pathways. As a result, the composite silicon anode delivers high capacity of 1672.2 mA h g −1 at 3C with 76.5% retention over 300 cycles, and notably sustains 1030.0 mA h g −1 at 3C even under 20 MPa. In full cells, it achieves 76.8 mA h g −1 at 3C under 20 MPa, 2.7 times higher than those based on pristine silicon anodes. Beyond silicon, this strategy can extend to other alloy‐type anodes (e.g., Sn), offering a general paradigm for constructing pressure‐resilient electron‐ion networks toward high‐rate ASSBs.

Superelastic Subcrystalline Rare‐Earth Ceramic Nanofiber Aerogels Enable 1300°C‐Stable Upconversion Luminescence

ABSTRACT Real‐time noncontact temperature detection is critical for the reliable operation of specialized robots in extreme thermodynamic environments. Upconversion (UC) luminescent materials, owing to their temperature‐sensitive emission, offer a promising solution. However, traditional UC crystals are fundamentally limited by both severe thermal quenching above 250°C and intrinsic brittleness. Here, we break these barriers by developing a subcrystalline upconversion ceramic nanofiber aerogel through an interfacial phonon engineering strategy. Our approach embeds active rare‐earth nanocrystals within an amorphous alumina matrix, creating a tensile‐strained heterointerface that softens local phonon modes and efficiently scatters high‐frequency vibrations. This unique “phonon cage” architecture suppresses nonradiative decay pathways, enabling stable UC emission at the unprecedented temperature of 1300°C. Furthermore, the subcrystalline structure induces a higher‐order sinusoidal buckling behavior, endowing the aerogel with thermomechanical superelasticity. The aerogel fully recovers from 95% compressive strain and survives over 1000 fatigue cycles, retaining >80% of its elasticity after 100 rigorous compression cycles under 1300°C thermal load. This work paves the way for noncontact thermal sensing in extreme environments.

Multiresonant Membrane Metasurfaces for Multifunctional Molecular Absorption Sensing and Real Time Biochemical Tracking

ABSTRACT Label‐free identification and real time tracking of biochemical substances became critical for molecular diagnostics and chemical analysis, yet conventional resonant terahertz (THz) metasurface sensing relies on a single resonance, limiting spectral selectivity and dynamic capability. Here, we suggest multiresonant membrane metasurfaces and employ them for simultaneous static characteristic absorption detection and dynamic reaction monitoring within a single pixel. We consider a membrane metasurface supporting multiple quasi‐bound states in the continuum designed at target frequencies and enabling the tailoring of the field enhancement and frequency‐selective interaction with target analytes. As a proof‐of‐concept, we achieve label‐free detection of the characteristic absorption features of pefloxacin at 0.78 and 0.99 THz, and real time tracking of vitamin C oxidation and denaturation under ambient conditions. The kinetic profiles extracted from the THz amplitude evolution show excellent agreement with nonlinear reaction models (R 2 > 0.92), demonstrating quantitative biochemical tracking capabilities. Our results establish a versatile and scalable THz photonic platform that unifies static molecule identification and dynamic reaction monitoring, paving the way toward integrated on‐chip biochemical analytics and multifunctional metasurface sensors.

Targeting Nonclassical Monocytes via Artificial Cell‐Microneedles for Precision Psoriasis Therapy

ABSTRACT Current therapies for inflammatory skin diseases predominantly rely on broad systemic immunosuppression and lack precision toward defined immune‐cell subsets. Here, we identify CX3CR1 + nonclassical monocytes (NCMs) as an inflammatory monocyte subset that contributes to the amplification of psoriasiform inflammation, as supported by integrated analyses of human single‐cell transcriptomics, genetic depletion, and adoptive‐transfer models. To preferentially engage these disease‐associated NCMs, we engineer an artificial cell–microneedle platform, termed CX3@GUV‐DMF, comprising CX3CL1‐functionalized, drug‐loaded giant unilamellar vesicles (GUVs) embedded within a dissolvable hyaluronic acid (HA) microneedle array. Following intradermal insertion, surface‐presented CX3CL1 actively navigates GUVs to pathogenic CX3CR1 + NCMs, facilitating the targeted, sustained release of the loaded drug. In vivo evaluations and transcriptomic profiling demonstrate that this localized immunomodulatory strategy attenuates inflammatory myeloid activation, neutrophil infiltration, and Th17‐associated responses while promoting restoration of epidermal barrier‐associated programs. These findings establish a materials‐enabled strategy for subset‐oriented immune modulation and local inflammatory‐niche remodeling, advancing inflammatory skin therapy beyond nonspecific immunosuppression.

Programming of Complex Magnetic Profiles Enforced by 4D Printed Magnetic LCE Actuators

ABSTRACT Magnetic soft actuators enable untethered, contact‐free actuation yet they are fundamentally limited by the difficulty of programming complex, three‐dimensional (3D), spatially non‐uniform magnetic profiles. Here, we introduce a four‐dimensional (4D) printing‐enabled magnetic programming strategy that overcomes this challenge by magnetizing magnetically active liquid crystal elastomers (MLCEs) in thermally actuated target states. Digitally prescribed director architectures define deterministic 3D deformations at elevated temperature, which serve as intrinsic programming templates during magnetization under a spatially uniform magnetic field. Upon cooling, relaxation of the thermomechanical deformation transforms the initially uniform magnetization into a complex, spatially varying magnetic profile that encodes the target shape as a magnetically favoured configuration. This approach enables the recovery of thermally defined shapes at room temperature under low magnetic fields and allows bidirectional and multistate actuation via simple reversal of field direction. By integrating spatial magnetic programming with controlled geometric asymmetry, we demonstrate frequency‐tunable linear locomotion and chirality‐encoded clockwise or anticlockwise rotational motion in multimaterial soft robotic architectures. This strategy decouples magnetic profile complexity from magnetization hardware, providing a scalable, template‐free route to fully 3D magnetic programming for soft robotics and untethered actuators operating under low‐field conditions.

Prostate-Specific Membrane Antigen Positron Emission Tomography and Radiometabolic Therapies in Metastatic Castration-Resistant Prostate Cancer

Allogeneic CD70-Targeted Chimeric Antigen Receptor T-Cell Therapy for Advanced Renal Cell Carcinoma: Results From the Phase I TRAVERSE Trial

PURPOSE Treatment options for clear cell renal cell carcinoma (ccRCC) refractory to immune checkpoint inhibitors (ICIs) and targeted therapy are needed. ALLO-316 is an allogeneic chimeric antigen receptor (CAR) T-cell product that targets CD70-expressing ccRCC and resists immune rejection by targeting and eliminating patients' CD70 + alloreactive T cells. METHODS In the phase Ia/b TRAVERSE trial (ClinicalTrials.gov identifier: NCT04696731 ), patients with advanced ccRCC resistant to ICIs and vascular endothelial growth factor receptor–targeted therapy received lymphodepletion and ALLO-316 following a modified 3 + 3 design. Phase Ia evaluated ALLO-316 dose and fludarabine/cyclophosphamide (FC)–based lymphodepletion with/without the anti-CD52 antibody, ALLO-647. Additional patients were enrolled in phase Ib to confirm the expansion regimen identified in phase Ia. Primary end points were dose-limiting toxicities (DLTs) and adverse events (AEs). RESULTS Fifty-one patients were enrolled (phase Ib, n = 23). Patients received a median of four prior lines of therapy. The median follow-up was 28.8 months. DLTs occurred in two patients who received ALLO-647 (grade 3 autoimmune hepatitis; grade 5 cardiogenic shock). Grade ≥3 cytokine release syndrome, immune effector cell–associated neurotoxicity syndrome, and immune effector cell–associated hemophagocytic lymphohistiocytosis-like syndrome occurred in 2.0%, 0%, and 6.0% of patients, respectively. Most grade ≥3 AEs were hematologic (neutropenia 62.0%; white blood cell count decreased 54.0%; anemia 36.0%). In phase Ib, patients received FC and 80 × 10 6 CAR T cells. The objective response rate was 17.4% overall, 25.0% in phase Ib patients and 31.3% in phase Ib patients with CD70 tumor proportion score ≥50%. CONCLUSION ALLO-316 had manageable safety and encouraging antitumor activity in CD70-positive ccRCC. The TRAVERSE trial demonstrates proof of concept for the role of allogeneic CAR T-cell therapy in solid tumors.

Adjuvant Carboplatin for Early-Stage, Triple-Negative Breast Cancer: Taxane and Patient Selection