Browse Articles

A Mechanochemical Kolbe–Schmitt Reaction: Catechol Carboxylation Provides Building Blocks for Renewable Plasticizers

ABSTRACT Catechol, an important aromatic platform molecule which can be derived from biomass, was carboxylated by mechanochemical Kolbe–Schmitt reaction of disodium catecholate with CO 2 , providing a mixture of mono‐ and dicarboxylated catechol derivatives. While classical protocols require harsh reaction conditions, involving a high temperature and/or CO 2 pressure, a mild ball milling method was developed. This represents the first mechanochemical Kolbe–Schmitt reaction featuring a low CO 2 pressure and reactivity at room temperature. From the individual catechol‐based mono‐ and dicarboxylic acid reaction products, a library of novel renewable plasticizers was synthesized through esterification of the carboxylic acid functionalities and O ‐acylation of the phenolic hydroxy groups. The resulting esters were evaluated in poly(vinylchloride) (PVC) and poly(lactic acid) (PLA), revealing plasticizing efficiencies competitive to benchmark commercial plasticizers. These efficiencies were maintained when the best performing ester substitution pattern was installed on the ball mill‐derived mixture of mono‐ and dicarboxylated catechols, making resource intensive separation (e.g. chromatographic separation) of these ortho ‐dihydroxybenzene(di)carboxylic acids redundant.

Bilayer oxide memristor based on IGZO/IAZO structure for artificial tactile perception system

Rapid advances in neuromorphic computing and intelligent perception demand electronic devices that faithfully replicate human nociception, which is crucial for achieving human–computer interaction. In this study, a self-limiting and volatile transparent ITO/IGZO/IAZO/ITO memristor with a bilayer structure is designed and prepared. Compared with the traditional single-layer structure (ITO/IAZO/ITO and ITO/IGZO/ITO) devices, the bilayer device exhibits better I–V cycling stability, more focused current response, and narrower distribution of volatile voltage in terms of electrical performance, reflecting improved device consistency and reliability (μ increased by ∼43% and σ increased by ∼57%). The ITO/IGZO/IAZO/ITO memristors are able to effectively mimic the core characteristics of biological nociceptors, including “threshold,” “no adaption,” “relaxation,” and “sensitization of allodynia/hyperalgesia.” By integrating the IGZO/IAZO memristor with a piezoresistive force sensor, a biomimetic nociceptive sensing system is further constructed for responding to external noxious stimuli, which demonstrates the potential of self-protective neuromorphic electronics.

Multifaceted Molecular Design Enables Comprehensive Luminescence Modulation in Metalloligand‐Stabilized Gold Nanoclusters

ABSTRACT Photoluminescent metal nanoclusters hold promise for optoelectronics, photonics, and chemosensing, yet systematic modulation of their emission within a single system remains challenging. Here, we report two isostructural clusters, Au 13 @Au 3 ‐Cl and Au 9 Cu 4 @Au 3 ‐Cl , stabilized by a tridentate phosphine (NP 3 ) metalloligand. Both adopt an unprecedented “Au 9 M 4 (Au/Cu) icosahedron + Au 3 crown” configuration and exhibit high solid‐state PLQYs of 44.5% and 38.9%, respectively. In contrast, replacing NP 3 with a monophosphine ligand (BPP) affords Au 9 Cu 4 ‐Cl lacking the Au 3 crown, with a dramatically reduced PLQY of 0.6%, highlighting the crucial roles of NP 3 and the Au 3 crown in boosting luminescence. Distinct photophysical behaviors are observed: Au 13 @Au 3 ‐Cl shows phosphorescence, while Au 9 Cu 4 @Au 3 ‐Cl exhibits thermally activated delayed fluorescence (TADF), confirmed by femtosecond transient absorption spectroscopy. The role of Cu doping is further supported by the TADF activity of Au 9 Cu 4 ‐Cl . Coordinating anion substitution also modulates emission, with iodide promoting TADF in Au 13 @Au 3 ‐I . Moreover, the NP 3 ligand confers reversible protonation‐induced luminescence switching, enabling chemosensing potential. Collectively, these findings demonstrate a comprehensive investigation of TADF behavior and luminescence modulation in atomically precise metal nanoclusters, systematically engineered through heteroatom doping of the inner core, ligand design and anion exchange at the coordination surface, and outer‐sphere complexation and protonation.

Effects of interlayer electrons and high-order anharmonicity on phonon thermal transport of electride Sc2C

Electrides have attracted considerable research interest over the past four decades owing to their rich physical properties. However, their phonon thermal transport behavior, which is critical for thermal management applications, remains relatively unexplored. In this work, we systematically investigate the influence of high-order anharmonicity and interlayer electrons on the lattice thermal conductivity (κL) of Sc2C using density functional theory calculations combined with the phonon Boltzmann transport equation. Our results reveal that four-phonon scattering processes substantially suppress the κL of Sc2C, leading to remarkable reductions of 61.5% in the in-plane and 58.6% in the out-of-plane directions at 300 K due to the strong quartic anharmonicity. Furthermore, the removal of interlayer electrons markedly reduces the in-plane κL, while its effect on the out-of-plane component remains minimal. This anisotropic behavior is attributed to a competition between two opposing effects: an increase in phonon group velocity due to lattice contraction, and enhanced phonon scattering rates resulting from increased anharmonicity upon the removal of interlayer electrons. This work deepens our understanding of the phonon thermal transport property of Sc2C and provides a theoretical guidance for regulating the κL of electride materials.

Influence of Positional Isomerism in Weakly Solvating Ethers on Lithium Metal Deposition

ABSTRACT Lithium metal is a promising anode for next‐generation high‐energy batteries but faces issues like internal short circuits and low Coulombic efficiency (CE), limiting its performance. Although factors like solid‐electrolyte interphase (SEI) composition, charge transfer resistance, solvation structure, and solvent symmetry influence Li metal deposition, a unified descriptor remains absent. Here, we systematically investigate three positional isomers of weakly solvating ether solvents—dipropyl ether (DPE), butyl ethyl ether (BEE), and pentyl methyl ether (PME), selected to maintain the same C/O (carbon/oxygen) ratio of 6, allowing isolation of minor structural variations on Li metal deposition. By correlating charge transfer kinetics, solvation structure, SEI composition, and lithium microstructure with electrochemical performance, we identify key factors influencing deposition. The symmetric ether, DPE, with sluggish charge transfer kinetics and the most pronounced ion pairing, achieved the highest CE of 99.26%, followed by BEE (99.24%) and PME (98.89%). Increased ion pairing and enhanced LiF content in the SEI were found to have the strongest linear correlation with interfacial stability as reflected in CE. These findings challenge previous studies that faster charge transfer kinetics led to improved CE and enhance the understanding of designing weakly solvating ethers with optimized oxygen placement for future Li metal batteries.

Flatband-enabled catalysis of alkaline hydrogen evolution on kagome CoSn

Flatband materials offer a unique platform for catalysis due to their intrinsically localized electronic states and high density of states near the Fermi level. Here, we investigate the kagome intermetallic compound CoSn as a representative flatband catalyst for the hydrogen evolution reaction (HER) under alkaline conditions. First-principles calculations reveal that the CoSn(001) surface retains flatband features originating from Co dyz and dxz orbitals, which enhance hydrogen adsorption and facilitate water dissociation. Compared to elemental Co, CoSn exhibits significantly improved intrinsic activity, as confirmed by both theoretical analysis and experimental measurements. To further optimize catalytic performance, surface doping with 3d transition metals (X@CoSn, X = Ti, V, Cr, Mn, Fe, Ni) was employed. Among the dopants tested, Cr achieves the most favorable balance of HER energetics, exhibiting reduced water dissociation barriers and suitable adsorption strengths. A strong correlation between the dopant-modulated flatband center and OH* binding energy is established, demonstrating that flatband tuning directly governs surface reactivity. These findings highlight flatband engineering as an effective strategy for designing high-performance electrocatalysts.

A Modular Approach to <i>N</i> ‐Fluoroalkyl Amides via Nitrene Insertion Into Fluoroalkylcopper(I)

ABSTRACT We report herein the first copper‐mediated three‐component modular synthesis of N ‐fluoroalkyl amides from fluoroalkylcopper species ([Cu I ─CF 3 ], [Cu I ─CF 2 CO 2 Et], and [Cu I ─C 2 F 5 ]), a nitrene precursor (dioxazolone), and an electrophile, featuring broad substrate scope and the unprecedented construction of acyclic N ‐C 2 F 5 and N ‐CF 2 CO 2 Et structures. The reaction proceeds via reaction of the dioxazolone with the fluoroalkylcopper complex to generate a nitrene/Cu intermediate, followed by nitrene migratory insertion into the [Cu I ─C Rf ] bond as the pivotal step that directly forges the N– fluoroalkyl bond. Such a key step was supported by isolation and single‐crystal x‐ray characterization of intermediates [( L1 )Cu I N(CF 3 )(COAr)] 5c and [Cu I (N(CF 3 )(COAr)) 2 ] − 5d . Leveraging the versatile reactivity of copper, these intermediates react with various electrophiles to access a wide range of N ‐fluoroalkyl‐ N ‐alkyl(aryl)amides, and the derivatization of several drug molecules further demonstrates the synthetic utility of this approach.

<i>In situ</i> XRD study of strain evolution in AlGaN/GaN HEMT at high temperatures up to 1000 °C

The thermal stability and structural evolution of a GaN high-electron mobility transistor (HEMT) heterostructure grown on a Si (111) substrate were investigated using in situ high-temperature x-ray diffraction, reciprocal space mapping (RSM), Raman spectroscopy, and rocking-curve (RC) analysis at varying temperatures. The heterostructure, consisting of a p-GaN cap, an AlGaN barrier, and a GaN channel supported by two AlGaN/AlGaN superlattice buffer layers, maintained clear and periodic satellite peaks up to a temperature of 1000 °C, confirming structural integrity. Symmetric and asymmetric RSM results reveal that both the Si and GaN diffraction peaks shift with increasing temperature, consistent with thermal expansion, and show no significant broadening or relaxation throughout the heating process. The c-lattice constant follows the theoretical expansion predicted by the multi-frequency Einstein model, whereas the a-lattice expansion is slower due to in-plane strain constraints imposed by the underlying Si substrate and buffer layers. Irreversible strain relaxation and thermal mismatch-induced stress redistribution induce a residual compressive strain of roughly 0.3% in the GaN channel after cooling, which has been further confirmed in Raman spectra through a blue shift (∼1 cm−1) of the GaN E2 (high) phonon mode, corresponding to an in-plane strain of −0.15% ± 0.16%. RC analysis revealed an increase in both screw and edge dislocation densities of 28% and 12%, respectively. These results collectively demonstrate that the GaN HEMT heterostructure exhibits robust crystalline stability up to 1000 °C without cracking due to strain relaxation, with only minor strain redistribution and limited dislocation activity, providing experimental evidence for GaN devices' applications under high-temperature conditions.

Electrooxidative C‐C Fragmentation of Aromatic Radical Cations for Cascade Benzylic Multifunctionalization

ABSTRACT Oxygen, nitrogen, and halogen‐containing functional groups are ubiquitous in complex small molecules. The installation of multiple carbon‐heteroatom bonds by the simultaneous functionalization of contiguous C–H/C–C bonds in a selective fashion is highly desirable in polymers degradation, skeletal editing, and petroleum cracking. However, achieving simultaneous, multi‐site functionalization of relatively inert C–C/C–H bonds with precise control over site‐, regio‐, and oxidation‐state selectivity remains challenging, particularly due to competing overoxidation and decomposition. Here we report the electrooxidative selective C‐C fragmentation of aromatic radical cations for cascade benzylic di‐ and trifunctionalization in simple alkylarenes by iterative dehydrogenation and oxygenation. Central to our approach is the controlled formation of olefin intermediates in situ at a rate carefully balanced to prevent polymerization and overoxidation. This strategy provides efficient access to diverse, high‐value di‐ or trifunctionalized products, including di‐ and triacetates, 2‐oxazolines, 1,2‐dibromoethanes, 1,3‐dibromo‐2‐ols, and 2‐(bromomethyl)oxiranes via controlled 4‐electron, 6‐electron, or 10‐electron oxidation events. Notably, the selective synthesis of di‐ versus trifunctionalization products is readily controlled through judicious choice of acids and nucleophiles.

Nonlinear refractive index compensation enables accurate spectral shifting in varactor-driven plasmonic waveguides

Precise control of spectral shifting in time-varying media is essential for reconfigurable microwave-photonic systems. However, varactor-based waveguides inherently exhibit strong capacitance–voltage nonlinearity, which is directly imprinted onto the refractive-index modulation and leads to severe distortion of the expected sinusoidal frequency trajectories. Here, we experimentally establish the complete nonlinear response chain, from applied voltage to refractive index to output spectrum in a varactor-loaded spoof surface plasmon polariton waveguide. By combining full wave simulations of the varactor-loaded waveguide with time-delay measurements, we obtain an accurate refractive-index–voltage mapping that reveals highly asymmetric refractive-index modulation under sinusoidal driving. This distortion explains the experimentally observed frequency-shift asymmetry and the deviation of 0.51 MHz from the ideal sinusoidal trajectory. Inspired by predistortion, we design an inverse-function-based compensation voltage waveform using the experimentally calibrated n–V mapping. This compensated waveform restores a nearly ideal sinusoidal refractive-index profile inside the waveguide. The symmetric frequency shift exhibited by the compensated device agrees excellently with analytical theory and COMSOL simulations. These results provide a broadly applicable workflow for calibration and control, mitigating intrinsic varactor nonlinearity in reconfigurable waveguides and enabling accurate dynamic spectral control.

Tailoring high-quality germanium crystal via high magnetic field

High-quality germanium single crystals are vital for infrared and semiconductor applications but are plagued by melt convection during growth. This study demonstrates that applying a 10 T high magnetic field during directional solidification stabilizes the solid–liquid interface and reduces dislocation density by over 35%. The resulting crystals exhibit significantly higher electrical resistivity and an 89% improvement in infrared transmittance. This method provides a practical ground-based route to achieving microgravity-like growth conditions for superior germanium crystals.

Enhanced performance of a hybrid PV/T V-shaped solar still using a graphene–silver–silica composite

Dynamic changes of monocytes-related immune activation in people with HIV switching to long-acting injectable cabotegravir plus rilpivirine

Abstract The aim of this study was to examine the dynamic changes in monocyte/macrophage- and dendritic cell (DC)-related immune activation in people with HIV (PWH) before switching to long-acting (LA) injectable cabotegravir (CAB) plus rilpivirine (RPV) (T0), after six (T6m) and twelve months (T12m). A total of 30 aviremic PWH switching to LA CAB plus RPV, and 32 healthy donors (HDs) were enrolled. At each time point, in comparison to HDs, PWH exhibited higher classical and intermediate monocyte counts and lower slanDC and pDC counts. Compared to HDs, in PWH non-classical monocyte counts were higher only at T0. PWH exhibited elevated sCD163 and sCD14 plasmatic levels at each time point, in comparison to HDs. No virological failure was observed. At T12m, no differences in the total cell-associated HIV-1 DNA levels compared to T0 were found. The longitudinal evaluation showed a significant reduction in non-classical and intermediate monocyte counts at T12m compared to T0 and an increase in classical monocyte and pDC counts. Furthermore, a reduction in sCD14 plasma levels was observed. The constant drug concentrations provided by CAB plus RPV injections appear to be effective for a sustained and deep virological suppression that may reduce monocyte/macrophage activation in PWH.

Engineering bright directional emission from 2D semiconductor in double resonance metal-dielectric metasurface cavity

A novel complex Fermatean fuzzy formalism with improved score function and aggregation operators

Exploring the gravito-optic effect for gravity sensing applications

Optimization of Falcon concentrator for iron recovery from blast furnace sludge using Box–Behnken design

Neuroergonomic evaluation of risk-warning eHMI penetration rates in vehicle platoons: effects on pedestrians’ mental workload, situation awareness, and gap acceptance

Antifungal susceptibility and in vitro virulence characteristics of clinical Magnusiomyces/Saprochaete isolates: a multicenter study from Türkiye

Abstract Invasive infections due to Magnusiomyces / Saprochaete species are an emerging problem in immunocompromised patients and are often underrecognized because of misidentification and intrinsic resistance to some antifungals. This multicenter study investigated the species distribution, antifungal susceptibility patterns, and key virulence traits of clinical isolates from Türkiye. A total of 133 clinical isolates collected between 2010 and 2024 from 18 hospitals in 10 cities were identified by MALDI-TOF MS and ITS/LSU sequencing. MICs of amphotericin B, fluconazole, voriconazole, itraconazole, posaconazole, and flucytosine were determined using the EUCAST broth microdilution method. Biofilm formation and esterase, caseinase, secreted aspartyl proteinase, phospholipase, and hemolysin activities were assessed phenotypically. Sequencing identified 107 isolates (80.4%) as Magnusiomyces capitatus and 26 (19.6%) as Magnusiomyces clavatus , MALDI-TOF MS identified 106 (79.7%) as M. capitatus and 27 isolates (20.3%) as M. clavatus . There was 99.2% agreement between MALDI-TOF MS and sequencing results. Voriconazole, amphotericin B, and posaconazole showed the lowest MICs, whereas fluconazole displayed wide MIC ranges and limited activity. Overall, 97.7% of isolates were strong biofilm producers, with significantly higher biofilm production in M. capitatus . In contrast, M. clavatus showed higher caseinase and esterase activity. This study provides the most extensive multicenter dataset on Magnusiomyces / Saprochaete in Türkiye and underscores their considerable pathogenic potential through strong biofilm formation and tissue-degrading enzyme activities. Accurate species-level identification using MALDI-TOF MS supported by molecular methods is essential, and limited fluconazole activity suggests that voriconazole and amphotericin B should be prioritized in species-guided treatment strategies.

The role of review structure in perceived helpfulness

Abstract Online product reviews are a pervasive form of public feedback, yet research on their perceived helpfulness has focused almost exclusively on overall sentiment. Drawing on feedback literature, we propose that review structure—the sequencing of positive and negative content across the evaluative message—shapes helpfulness above and beyond aggregate valence. We conducted an exploratory study by analyzing 195,675 Amazon reviews using growth curve modeling to capture each review’s opening tone and valence trajectory. Results show that the most effective structures depend on product ratings. For highly rated products, reviews that grow increasingly positive are most helpful, while those that turn negative are least. For average-rated products, progressively negative trajectories enhance helpfulness, whereas reviews that start negative and grow positive are least effective. For low-rated products, reviews are judged most helpful when they open constructively before introducing criticism. These findings advance theories of online reviews and feedback by showing that how evaluative information is organized matters as much as what is said.