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Remote Desaturation of Unprotected Amines and C─H Amination of Alkanes by Polarity‐Matched N‐Radical Cations
ABSTRACT A CuCl‐catalyzed strategy enables practical, selective, and efficient δ desaturation of unprotected amines. These bifunctional molecules allow rapid conversion of simple amines to privileged heterocycles in medicine. The key radical relay mechanism is an interrupted Hofmann–Löffler–Freytag (HLF) reaction, which may now be carried out without protecting groups. Based on ‘radical polarity matching’ analysis, we show here that N‐radical cations are ideal intermediates for facilitating efficient and selective 1,5‐H‐atom transfer (HAT) of unprotected amines. Mechanistic probes illustrate the scope, rate, selectivity, and utility of these distal amino alkenes. Computational studies compare the importance of kinetic (radical polarity) over thermodynamic (bond strength) factors in predicting HAT reactivity. Extension to an intermolecular variant allows the direct, desaturative C─H amination of alkanes in a net triple C─H functionalization.
Real-time HIL validation of a lyapunov-guaranteed optimal FOPID controller for quadrotor UAV trajectory tracking
Abstract This paper presents the real-time Hardware-in-the-Loop (HIL) validation of a robust 6-Degree-of-Freedom (6-DoF) Fractional-Order Proportional-Integral-Derivative (FOPID) control architecture, optimally tuned via the Artificial Gorilla Troops Optimizer (GTOA), for quadrotor Unmanned Aerial Vehicle (UAV) trajectory tracking. First, a comprehensive kinematic and dynamic model is developed, and the control architecture is designed by decoupling the UAV into fully-actuated and under-actuated subsystems through a cascaded inner-outer loop strategy. The global asymptotic stability is mathematically established via Lyapunov theory, and a dynamic Lyapunov penalty mechanism is further integrated into the GTOA objective function to enforce this stability condition across all candidate solutions throughout the optimization process. Subsequently, GTOA is applied to obtain the optimal gains that minimize the Integral of Time-Weighted Absolute Error (ITAE). Real-time HIL experiments are conducted on an industrial OPAL-RT OP4510 real-time target simulator, where the proposed GTOA-FOPID is evaluated against the African Vultures Optimization Algorithm (AVOA)-FOPID, alongside the baseline Particle Swarm Optimization (PSO)-tuned fractional-order and integer-order PID controllers. This comparative study evaluates the proposed architecture from two independent perspectives. First, the fractional-order operators are assessed against a PSO-tuned integer-order PID controller, isolating the contribution of the fractional calculus extension. Second, the GTOA is evaluated against AVOA and PSO, representing a modern metaheuristic and a standard baseline, respectively, across the identical FOPID architecture, isolating the contribution of the optimization strategy. Experimental results demonstrate the superiority of the fractional operators over the traditional integer-order PID controller. Furthermore, the proposed GTOA-FOPID achieves superior transient performance, precise trajectory tracking, and enhanced robustness under realistic hardware constraints and computational delays.
A Highly General Potential‐Gating Strategy for Electrocatalytic Upcycling of Waste Polyester Plastics
ABSTRACT Electrocatalytic upcycling of waste polyester plastics driven by renewable electricity offers a sustainable route for resource utilization, yet its practical implementation is hampered by the poor selectivity control stemming from the inherent complex monomer of polyesters. Herein, we propose a potential‐gating principle for the selectivity‐controllable upcycling of α,ω‐diols and hydroxy acids—the most pivotal monomers of polyester—and design a potential‐gated PVP‐Pd‐Ni(OH) 2 ‐CV/NF catalyst. This catalyst enables precise manipulation of product distribution simply by switching the applied potential without the need for catalyst replacement, while demonstrating broad applicability to seven polyesters. Moreover, the composite catalyst exhibits a sevenfold activity enhancement over the Pd/NF benchmark. Mechanistic investigations reveal that the adsorption behavior of hydroxy acid intermediates is the key selectivity‐determining step. Sequential electrolysis of real post‐consumer polyester hydrolysates over four stages for 198 h retains high target product selectivity (84%–98%), thus showcasing a general and sustainable route for plastic waste recycling.
Experimental analysis of nanofiber embedding and layer thickness on fracture toughness in fiber–epoxy laminates
In Situ Tracking of Radical Evolution in a Conjugated Covalent Organic Framework for Reversible Sodium Storage
ABSTRACT Covalent organic frameworks (COFs) have emerged as promising platforms for sodium‐ion storage owing to their tunable redox‐active sites and ordered porous architectures. However, the role of radical intermediates in their electrochemical processes remains elusive due to the lack of direct experimental evidence. Herein, we report a highly crystalline β‐ketoenamine‐linked COF (BT‐COF‐AA) that delivers exceptional rate capability and ultralong cycling stability over 10 000 cycles at 5 A g − 1 . More importantly, in situ electron paramagnetic resonance (EPR) spectroscopy provides time‐resolved and direct observation of transient radical intermediates, enabling the elucidation of a sequential sodium‐ion storage mechanism. Specifically, Na + ions initially coordinate with nitrogen sites in benzothiadiazole units, triggering localized electron transfer and the formation of stabilized radicals. Subsequent sodiation occurs at carbonyl oxygen sites, generating ketyl radicals accompanied by dynamic electron delocalization across the conjugated framework. This reversible radical evolution establishes a framework‐coupled redox pathway that underpins the outstanding electrochemical performance. Combined experimental and theoretical results reveal a radical‐mediated charge storage mechanism and provide fundamental insights for the rational design of high‐performance organic electrode materials.
Vortex-induced resistive state in Nb-Pb-Nb heterostructure
Abstract We investigate the current-driven resistive state of two-dimensional Pb–Nb core–shell superconductors within the time-dependent Ginzburg–Landau framework, focusing on how proximity induced inhomogeneity and self field effects govern vortex–antivortex (v-av) dynamics and superconducting fragmentation. The system consists of a type-I Pb core surrounded by a type-II Nb shell coupled through a smooth proximity interface, which produces a spatially nonuniform reduced temperature $$T/T_c(\textbf{r})$$ and redistributes both the order parameter and the transport current. By increasing the applied current, we identify a sequence of distinct dynamical regimes. At low currents, dissipation originates from edge-assisted v-av nucleation in the Nb shell, while the Pb core remains a robust superconducting backbone. As the current increases, v-av clusters grow and coalesce inside the Nb layer, progressively suppressing its superconductivity and fragmenting the proximity-coupled network. This process leads to the emergence of isolated Pb superconducting islands that are weakly connected by highly dissipative Nb channels and sustain intermittent phase-slip dynamics. At still higher currents, the Nb shell becomes strongly degraded and transport is governed by edge-driven bursts of v-av activity surrounding the Pb islands, producing a highly nonlinear resistive response. For comparison, we analyze a homogeneous Pb film under the same conditions. Although Pb is a type-I superconductor, the transport self-field induces an intermediate resistive state characterized by a fixed array of superconducting islands embedded in normal regions near the edges. Remarkably, in the high-current limit, the Pb–Nb heterostructure evolves toward a similar island topology, indicating that proximity coupling becomes progressively weaker and self-field effects dominate the spatial organization of superconductivity. Our results establish a mesoscopic framework in which proximity effects, transport self-fields, and vortex dynamics jointly govern dissipative states in hybrid superconducting heterostructures.
Monolithic Porous Polymer Architectures for Visible‐to‐UV Upconversion‐Driven Photochemical Reactions
ABSTRACT Triplet–triplet annihilation‐based photon upconversion (TTA‐UC) expands the accessible spectral window for photochemical transformations by generating high‐energy photons from low‐energy excitation. Although TTA‐UC has been widely demonstrated in solution and in various solid‐state formats, examples of polymer materials capable of efficient visible‐to‐ultraviolet (vis‐to‐UV) upconversion under low excitation intensities remain scarce. Achieving vis‐to‐UV TTA‐UC in a porous solid is particularly challenging because it requires balancing chromophore proximity for TTA with the suppression of aggregation‐induced quenching, while simultaneously preserving substrate accessibility. Here, we introduce porous polymer monoliths that enable solid‐state TTA‐UC specifically designed for heterogeneous photochemistry. By embedding sensitizer‐annihilator dye pairs into polymer matrices with controlled co‐continuous porosity, we create monolithic architectures that display upconverted UV emission from blue light at excitation intensities below a few mW cm − 2 , with the operational wavelength further extended to green light excitation. The porous architecture enhances energy transfer to reaction substrates, providing a versatile platform for heterogeneous photochemical processes. Owing to their robustness and tunability, these monoliths are promising candidates as heterogeneous photoreactors, opening new opportunities for scalable and sustainable photochemistry.
Time-of-flight neutron radiography for differentiating ice and water during phase transitions in natural porous media
Abstract Measurement of coexistent liquid water and ice distributions is useful for many materials and systems such as fuel cells, concrete, snow, and soil. Energy-resolved neutron imaging is a promising technique for these measurements by exploiting differences in neutron cross-section between ice and water at cold neutron energies. Until now, energy-resolved neutron imaging techniques have only been used with relatively thin and non-natural samples. Given the importance of liquid water and ice distributions in many natural porous materials, we investigated the feasibility of using time-of-flight neutron radiography for two natural porous materials. Two exploratory experiments were performed with a model system of glass beads (simple soil analogue) and a natural snow sample with sample thicknesses of 5 mm. The experiments demonstrated that the relative attenuation could be used to distinguish between liquid and solid water phases as well as to dynamically track the phase transition within these porous materials. The results also demonstrated that significant challenges with respect to the scattering in thick samples, inconsistent thicknesses associated with spatial variations of the porosity, and time-variant structures of the porous matrix remain.
Narrowband Hydrocarbon Emitters Enabled by Stereo‐Locked Through‐Space Interactions
ABSTRACT High‐purity emitters with a narrowband emission are a critical requirement for next‐generation displays and lighting, yet it remains a formidable challenge for purely organic materials, particularly in the pure‐violet region. Herein, a general molecular design strategy based on the “stereo‐lock” concept, represented by diarylbenzene derivatives solely from carbon and hydrogen, is presented. This strategy effectively suppresses intramolecular C─C/C─H stretching and attenuates vibronic coupling via intramolecular through‐space interactions between two aryl groups, yielding a record full width at half maximum (FWHM) of merely 6 nm at 80 K from a single molecule. In the solid state, their aggregates with intermolecular positive exciton coupling induce quantum interference that selectively quenches the v 0‐0 transition, resulting in an FWHM of 17 nm at room temperature. Leveraging this synergy, diarylbenzene‐based OLED devices with pure‐violet electroluminescence with an 18 nm FWHM and a CIE coordinate of (0.165, 0.022) are achieved. This stereo‐lock architecture circumvents the fundamental limitation of vibronic coupling in pure hydrocarbons and addresses the absence of high‐color‐purity violet OLEDs, establishing a powerful and versatile design paradigm for narrowband emitters.
Artificial intelligence-based adaptive gain tuning for robust data-driven cardiac rhythm control under uncertainty
Unprotected <i>C</i> ‐Aryl Glycosides From Native Sugars via Glycosyl Sulfonyl Hydrazides: A Thermal Cap‐and‐Glycosylate Strategy
ABSTRACT We report a thermal cap‐and‐glycosylate strategy for the direct, protecting‐group‐free synthesis of unprotected aryl C‐glycosides from native sugars, employing glycosyl sulfonyl hydrazides as glycosyl radical precursors under redox‐neutral nickel catalysis. This two‐step process avoids photoirradiation, chromatography, and external redox agents. 11 Unprotected monosaccharides react with high 1,2‐ trans selectivity, tolerating diverse functional groups and heteroarenes. The utility is showcased by two‐step assembly of gliflozin drugs, their analogues and Neopetrosin C. This platform positions glycosyl sulfonyl hydrazides as a versatile radical source and a scalable alternative to photoinduced C‐glycosylation.
Spatially customized demand estimation for demand responsive transit
Abstract Demand-responsive transit (DRT) has emerged as a flexible mobility solution for addressing service blind spots in areas underserved by conventional public transportation. However, empirical research on DRT demand estimation remains limited, especially in the context of regional heterogeneity and zero-inflated demand. This study proposes a data-driven DRT demand estimation framework using operational records from two contrasting regions in Incheon, South Korea. Yeongjongdo is a tourism- and airport-oriented area with a high floating population and strong temporal variability, while Geomdan New Town is a residential district with relatively stable travel patterns. A grid-based origin–destination (O–D) modeling structure was employed, incorporating spatial variables such as land use, population dynamics, facility distribution, and public transport accessibility. Multiple region-specific machine learning models were developed and evaluated to estimate planning-oriented mean daily demand for each O–D-hour. A comparative analysis of alternative model configurations showed that the appropriate model structure varied according to regional demand conditions. In Yeongjongdo, the proposed two-stage model, which combines demand-occurrence classification and conditional regression, achieved the best overall performance, with a test MAE of 0.0022 and RMSE of 0.0105. These values represented reductions of 37.1% and 42.0%, respectively, relative to the strongest direct regression benchmarks. In contrast, direct regression was more effective in Geomdan New Town, achieving a test MAE of 0.0071 and RMSE of 0.0190. These results indicate that the relative performance of direct regression and two-stage prediction may vary across regional demand contexts.
Allegra Franchino
Design, synthesis, and characterization of glyoxime-functionalized hydroxypropyl methylcellulose/acrylic acid hydrogel for efficient removal of lead (II) ions from aqueous media
Proton‐Switching Regulates Interfacial Iodine Chemistry for Long‐Life Zinc–Iodine Batteries
ABSTRACT Aqueous zinc–iodine (Zn–I 2 ) batteries are promising candidates for safe and cost‐effective energy storage, yet their practical application is limited by uncontrolled iodine speciation at electrified interfaces, driving severe polyiodide shuttling and parasitic reactions that cause rapid capacity fading. Existing strategies predominantly rely on static confinement or adsorption, which cannot adapt to evolving iodine speciation during charge–discharge, causing a trade‐off between shuttle suppression and redox kinetics. In this study, we report a proton‐switching strategy that regulates interfacial iodine chemistry via electrochemically driven protonation–deprotonation within an imine‐linked two‐dimensional polymer framework, thereby dynamically rewiring interfacial electrostatics during cycling. During discharge, protonation of imine generates positively polarized C═NH + sites that stabilize I − through electrostatic interactions, enabling controlled reduction of polyiodides without accumulation. Upon charging, deprotonation restores the neutral framework, favoring polyiodide stabilization and efficient iodine oxidation. As a result, the constructed Zn–I 2 battery delivers 51 000 cycles at 20 A g −1 at 25°C and sustains over 70 000 cycles at −20°C. This durability is retained at a high iodine loading of 35.7 mg cm −2 , delivering an areal capacity of 5 mAh cm −2 over 2000 cycles with negligible decay, placing this system among the most durable Zn–I 2 batteries.
A low-temperature spray-cyclone system for zero-liquid discharge treatment of RO brine using extended two-phase CFD modeling and experimental validation
Chromium‐Catalyzed Stereodivergent Carbonyl Addition Dictated by Non‐Covalent Interactions
ABSTRACT Catalytic stereodivergent synthesis, which accesses the full complement of stereoisomers from a common precursor set, is a paramount objective in drug discovery. However, achieving this control via radical‐involved pathways remains a formidable frontier due to the transient nature of open‐shell intermediates. Here, we report a unified chromium‐catalyzed platform that harnesses a radical–polar crossover mechanism to achieve the fully ligand‐controlled stereodivergent synthesis of chiral β ‐fluoro alcohols. We demonstrate that the stereochemical outcome is not inherent to the substrate but is dictated by the ancillary ligand through distinct non‐covalent interactions: a chiral bisoxazoline ligand enforces a rigid transition state via fluorine‐mediated hydrogen bonding to selectively deliver syn ‐diastereomers, whereas a chemically distinct pyridine–imidazoline ligand exploits electronic desymmetrization via π–π stacking to invert selectivity toward anti ‐isomers. Notably, this protocol enables the programmable assembly of all four stereoisomers of fluorosugar derivatives.
Design of a novel reliable 9-level switched capacitor-based inverter with low voltage stress on the devices for renewable energy applications
Generalizable Strategies for the Synthesis of Cereblon‐Recruiting PROTAC Prodrugs
ABSTRACT Cereblon (CRBN)‐recruiting PROTACs (proteolysis‐targeting chimeras) are among the most clinically advanced degraders but remain challenging to chemically modify for translation to prodrug‐based delivery strategies. Here, we report three orthogonal approaches—triazole quaternization, tertiary‐amine alkylation, and installation of a hydroxyl linker—that enable chemoselective, high‐yielding syntheses of CRBN‐recruiting PROTAC prodrugs. These strategies allow incorporation of self‐immolative linkers whose cleavage kinetics can be predictably tuned to release the parent PROTAC, which is demonstrated in the context of PEGylated macromonomer and bottlebrush prodrug macromolecular scaffolds. In multiple myeloma models, representative PROTAC‐bottlebrush prodrugs (PROTAC‐BPDs) induce cellular potency profiles that follow the designed PROTAC release rates, confirming that the observed protein degradation and cytotoxicity arise from effective prodrug linker cleavage. Collectively, this work establishes generalizable approaches for constructing prodrugs of CRBN‐based PROTACs, expanding the synthetic space for targeted protein degradation and providing new design principles for controlling degrader activation, selectivity, and in vivo delivery.