Browse Articles

Soft tissue and dentoskeletal changes associated with mandibular molar distalization using clear aligner therapy: a retrospective cross-sectional CBCT study

Molecular Descriptor‐Directed Microstructural Regulation of Asphalt‐Derived Hard Carbons for Advanced Sodium‐Ion Batteries

ABSTRACT Asphalt is a promising precursor for hard carbon anode in sodium‐ion batteries, owing to its low cost and high carbon yield. However, its complex molecular composition leads to uncontrolled carbonization and unpredictable electrochemical performance. Here, we introduce two quantitative molecular descriptors: the aromatic substitution index ( f a s ) and short‐chain substitution index ( R ) that enable precise correlation between precursor molecular topology and hard carbon microstructure. Through systematic solvent fractionation and multi‐scale characterization, we discover that short‐chain pendant alkyl groups with high R values enhance oxidative crosslinking to suppress graphitization, while high‐degree aromatic substitution with high f a s values promotes the formation of uniform closed pores and optimizes structural disorder. The optimized hard carbon achieves superior sodium storage performance (326 mAh g −1 , 93% capacity retention after 500 cycles, 204 mAh g −1 at 5 A g −1 ) with exceptional rate capability. This descriptor‐based approach provides both fundamental insights into microstructure formation and a practical strategy for precursor selection, paving the way for rationally designed high‐performance hard carbon anodes.

ZIF-67-preloaded bacterial cellulose aerogel with strong Lewis acid–base interactions fabricating homogeneous solid composite electrolyte for lithium metal batteries

Low ionic conductivity of solid electrolyte and unstable Li/solid electrolyte interface greatly restrict the development of solid-state lithium metal batteries (LMBs). In this study, a novel design strategy of solid composite electrolyte (SCE) was proposed by utilizing a ZIF-67-preloaded bacterial cellulose aerogel as a rigid scaffold. The as-prepared bacterial cellulose aerogel via freeze-drying route is highly porous with large quantities of accessible polar sites, which is beneficial to not only uniform growth of ZIF-67 nanoparticles on it owing to strong and adequate Lewis acid–base interaction between them, but also full accommodation of polymer matrix deriving from in situ polymerization of 1,3-dioxolane at the assistance of ZIF-67 “molecule bridge.” The well-distributed ZIF-67 with ordered channels further promotes Li+ migration and uniforms Li+ flux. These merits endow the SCE with continuous, rapid Li+ transport pathway as well as rigid-flexible coupled framework, thereby achieving highly reversible Li plating/stripping process and superior cycle capability of the LMBs.

Effects of analgesia on the response to a noxious stimulus in Norway lobsters (Nephrops norvegicus)

Abstract There is evidence that decapod crustaceans have the capacity to experience aversive states associated with nociception, highlighting the need for humane treatment. Behavioural and physiological responses to nociceptive stimuli may be reduced with analgesic drugs, yet little is known for decapods about effective options. In this study, the impact of electric shock on behaviour and physiology was investigated in Norway lobsters. Behaviour was monitored from before the shock to two hours after, with and without drugs with analgesic properties. Haemolymph and nervous tissues were analysed for stress indicators, including lactate, glucose, and gene expression. Electric shock induced tail flipping responses, absent in sham groups, however this was significantly reduced in animals treated with a local anaesthetic and an analgesic; suggesting these responses were mediated by nociception. Aspirin and lidocaine were effective at reducing this shock-related behaviour, however aspirin injection increased grooming immediately after administration, with elevated haemolymph lactate and downregulated gene expression in ganglionic tissues. Overall, the acute shock stimulus did not produce long lasting effects, but both drugs reduced tail flipping during shock. These results underscore the potential of these drugs for laboratory use during invasive procedures, but also the broader ethical responsibility to incorporate welfare strategies in crustacean handling and stunning protocols.

Multifunctional Janus TiSBr monolayer: Strain-tuned synergy of ferrovalley, quantum anomalous Hall, and anomalous Nernst effects

Two-dimensional ferrovalley materials that simultaneously exhibit large valley polarization and high Curie temperature (Tc) are essential for advancing valleytronic devices. In this work, we propose a stable Janus TiSBr monolayer as a ferromagnetic valley system with a Tc of 355 K. First-principles calculations show that out-of-plane magnetization induces a pronounced valley polarization of 68.94 meV, which together with valley-contrasting Berry curvature leads to the anomalous valley Hall effect (AVHE). Furthermore, biaxial strain provides effective control over its magnetic, valley, and topological properties. Remarkably, under a narrow compressive strain window between −3.89% and −4.0%, the system undergoes a transition from the AVHE to both the quantum anomalous Hall effect and the anomalous Nernst effect, revealing its multifunctional nature. These results establish the Janus TiSBr monolayer as a promising platform for integrated valleytronic, spintronic, and topological applications.

Atomically Dispersed Cobalt on Ionic Carbon Nitrides for Selective and Efficient Nitrate Electroreduction to Ammonia

ABSTRACT Direct electrochemical conversion of nitrate to ammonia (NH 3 ) represents a sustainable route for NH 3 production while simultaneously mitigating nitrate pollution. Carbon nitrides (CNs) have emerged as promising supports for transition‐metal single‐atom catalysts due to their high nitrogen content and abundant coordination sites. However, conventional CNs generally suffer from poor electrical conductivity and difficulty in stabilizing high densities of atomically dispersed metal centers, which limits catalytic efficiency and selectivity in the nitrate reduction reaction. Herein, we overcome these limitations by constructing cobalt poly(heptazine imides) ( Co PHI), an ionic carbon nitride in which Co 2+ species are coordinated to negatively charged imide‐bridging nitrogen atoms. This coordination environment enables a high density of isolated Co active sites (1.092 wt.%) while enhancing charge transport through the PHI framework. As a result, Co PHI achieves a Faradaic efficiency of 93.5% and an NH 3 yield rate of 46.1 mg·h −1 ·mg cat. −1 at −0.8 V versus RHE, outperforming conventional Co─N─C and Co ─C 3 N 4 systems. Combined experimental and theoretical studies show that Co PHI promotes strong nitrate adsorption, facilitates water dissociation to supply protons, and stabilizes key intermediates, collectively enabling efficient and selective nitrate‐to‐ammonia conversion.

Twist-controlled phonons and symmetry breaking in asymmetric moiré van der Waals heterostructures

Twistronics in van der Waals heterostructures enables programmable electronic, vibrational, and nonlinear optical responses through moiré superlattices, but most platforms are assembled from high-symmetry layers, restricting the accessible symmetry landscape. Here, we introduce an intrinsically asymmetric moiré system by fabricating a van der Waals heterobilayer of monolayer WSe2 (D3h group, C3 rotational symmetry) and monolayer Mo0.4W0.6Se2 alloy (P1 group, C1 rotational symmetry) with intrinsically broken rotational symmetry. Using polarization-resolved Raman spectroscopy in combination with second-harmonic generation (SHG) microscopy over the twist-angle range (0°–60°), we track how interlayer coupling, lattice reconstruction, and global symmetry evolve with twist angle, showing that interlayer phonons act as sensitive probes of the moiré length scale and reveal a continuous crossover from strong coupling near 0°/60° to weak coupling approaching ∼30°. Circularly polarized Raman measurements resolve nearly degenerate phonons and uncover a twist-tunable splitting of the in-plane E2g mode of WSe2. Polarization-resolved SHG visualizes twist-driven modulation of the effective point-group symmetry, with polar patterns evolving from sixfold, C3-like to twofold, C1-like lobes, quantitatively captured by a bond angular momentum model. Our results establish the combination of native symmetry breaking and twist engineering as a generic strategy for programming phonon and symmetry landscapes in van der Waals materials, opening a route to designer moiré crystals in which interfacial coupling, nonlinear optics, and correlated quantum degrees of freedom can be co-engineered within a single, twist-tunable architecture.

Regiodivergent C3 and C4 Amination of Quinolines via Radical and Ionic Pathways

ABSTRACT Controlling the site of amination on N‐heteroarenes is pivotal for rapid exploration of structure–activity relationships, yet a single‐precursor platform that toggles between C3 and C4 amination of quinolines has remained elusive. Here we report a regiodivergent method that channels quinoline amination to C3 or C4 through orthogonal radical and ionic manifolds. Under visible‐light, donor‐assisted electron‐donor–acceptor (EDA) conditions, homolytic N─N cleavage of N‐aminoquinolinium salts generates N‐centered radicals that selectively install amino groups at C3 via capture by an enamine intermediate (radical pathway) formed through traceless nucleophile‐induced dearomatization. In the absence of light and donor, the same quinolinium salt undergoes a two‐electron ionic process: S N Ar‐type addition of amines at C4, followed by base‐promoted rearomatization to furnish C4‐aminated products. The method proceeds under mild conditions, accommodates a broad range of quinolines and amine partners, and enables late‐stage diversification. Mechanistic experiments support an EDA‐initiated origin for the C3 manifold and an ionic mechanism for C4, establishing condition‐gated control over quinoline C─N bond formation.

Epitaxial growth of topological insulator <b> <i>β</i> </b> -Ag2Te thin films

We report epitaxial growth of β-Ag2Te thin films by molecular beam epitaxy. β-Ag2Te, recently identified as a topological insulator, was grown by depositing Ag on an InP substrate at room temperature, followed by Te supply at an elevated temperature. X-ray diffraction measurements and transmission electron microscopy analyses confirmed the (002) crystal orientation and the epitaxial atomic arrangement of β-Ag2Te thin films. Electrical transport measurements revealed that the β-Ag2Te thin film exhibits two-dimensional metallic conduction while the bulk remains insulating. The epitaxial β-Ag2Te thin films obtained here provide a viable platform for investigating emergent phenomena arising from surface Dirac states and for designing heterojunction-based device structures.

Conductivity conversion of N-doped diamond by additional B ion implantation

We report the first successful formation of inversion doping in diamond achieved by ion implantation, realizing conductivity conversion from n-type to p-type. Type Ib diamond containing nitrogen donors (∼3.3 × 1019 cm−3) was implanted with boron ions at multiple energies (5–200 keV) to achieve a uniform depth profile up to ∼400 nm. The implantation was performed with boron concentrations ranging from 2 × 1019 to 3.5 × 1020 cm−3, followed by high-temperature annealing. Electrical characterization revealed a transition from n-type to p-type conduction as the boron concentration exceeded the nitrogen donor level in the substrate. The heavily implanted sample (3.5 × 1020 cm−3) exhibited p-type behavior with a sheet resistance of 4 × 104Ω/□ at room temperature and an activation energy of 0.06 eV. This achievement represents the first demonstration of the conduction-type inversion in diamond by ion implantation, establishing a viable approach to locally form p-n junctions in the n-well region. The ability to locally form p-type regions within a nitrogen-rich diamond provides a decisive step toward complementary diamond transistor devices, proving that ion implantation doping is a practical and controllable method for realizing various diamond devices.

Hyperpolarization of Molecular Deuterium

ABSTRACT Hyperpolarized deuterium provides a promising alternative to hyperpolarized hydrogen for molecular sensing in NMR, particularly in hydrogen‐rich environments where proton detection is hindered by strong background resonances. Using a homogeneous iridium catalyst (IrIMes) and nicotinamide as substrate, we demonstrate the generation and detection of hyperpolarized molecular deuterium. The resulting resonance exhibits a pronounced partially negative line (PNL), strongly enhanced compared to thermal deuterium signal, and reproducible by simulation. A transient PNL is further observed during the initial phase of catalyst activation, highlighting sensitivity to transient intermediates. Notably, the enhanced PNL only arises in the presence of nicotinamide, confirming sensitivity to the presence of the substrate. These findings establish hyperpolarized orthodeuterium as a viable molecular sensor capable of providing valuable spectroscopic information of catalytic hydrogen‐bound complexes. Together with recent observations of PNLs in aqueous media, our results underscore the potential of hyperpolarized molecular deuterium to probe catalytic and enzymatic cycles under biologically relevant conditions.

Correlation between giant surface potential and enthalpy relaxation in vacuum-deposited organic films

It is well known that vacuum deposition of organic molecules possessing electric dipoles leads to spontaneous molecular orientation, resulting in the formation of a giant surface potential (GSP). The GSP is expected to be useful for energy-harvesting devices, and improving carrier injection in organic light-emitting diodes; therefore, maximizing the GSP is crucial for device performance. Here, we systematically investigate the factors governing GSP formation by examining the roles of glass transition temperature (Tg), substrate temperature (Tsub), and deposition rate using a series of organic materials, including adamantane derivatives, diarylethenes, and spiropyrans. The molecular orientation parameter ⟨cosθ⟩ exhibits a clear dependence on Tg, indicating that surface molecular dynamics during deposition play a dominant role. We demonstrate that the GSP slope is maximized when Tsub is maintained at approximately 0.8–0.85 Tg. This condition coincides with the maximum enthalpy relaxation of vapor-deposited organic glasses. Based on these results, we propose a three-regime model describing GSP generation as a function of surface molecular mobility (Tsub/Tg scaling), providing practical guidelines for maximizing GSP in vapor-deposited organic thin films.

Dual‐Redox Conjugated Bipolar Covalent Organic Framework Enables High‐Voltage Symmetric Proton Batteries

ABSTRACT Symmetric all‐organic proton batteries (SAOPBs) attract increasing attention for large‐scale energy storage due to their safe and superior rate performance, which is severely limited by the lack of suitable bipolar electrode materials that integrate reversible dual‐redox activity and high operating voltage within a single structure. Herein, we report a bipolar covalent organic framework (TAPT‐HAT‐COF) as both cathode and anode in symmetric proton battery. In this COF, the electron‐deficient pyrazine/carbonyl units and electron‐rich phenylimine groups establish two independent and reversible redox couples, achieving a high operating voltage of up to 0.83 V. Combined with in situ FTIR spectroscopy and theoretical calculations, TAPT‐HAT‐COF shows bipolar charge storage mechanism with the C═N and C═O groups served as reversible redox centers. Benefiting from the fully conjugated structure and abundant active sites, the assembled SAOPB exhibits high specific capacity of 108.5 mAh g −1 under 5 A g −1 with stable cycling over 3000 cycles. Moreover, when applied in a practical pouch cell, which delivers a specific capacity of 145.8 mAh g −1 at 0.5 A g −1 , confirming the material's potential for practical applications. The work can provide viable design strategy and model of bipolar COF materials for symmetric energy storage systems.

Elasticity assessment of intestinal tissues using endoscopic optical coherence elastography

Strain-based optical coherence elastography (OCE) is a functional imaging modality derived from optical coherence tomography (OCT), which evaluates biomechanical properties by measuring tissue strain. However, conventional Doppler phase-based strain estimation is highly susceptible to phase wrapping, particularly under conditions of unstable scanning speed, which is often exacerbated by non-uniform rotational distortion (NURD) in proximally driven endoscopic probes. To overcome these limitations, we propose a distal rotary scanning endoscopic OCE system integrated with a balloon catheter. By combining balloon inflation-induced excitation with circumferential scanning, the system enables stable and uniform elastography imaging of intestinal tissue while mitigating NURD-related artifacts. Displacement fields are estimated by calculating inter-frame phase differences of OCT images, based on which radial strain maps are reconstructed, thereby simplifying the phase-unwrapping process. Experiments conducted on tissue-mimicking phantoms and ex vivo porcine intestines confirm the feasibility of the proposed method. The results indicate that the system can simultaneously capture high-resolution structural images and radial strain information from localized intestinal tissues, demonstrating significant potential for clinical applications in the early diagnosis and therapeutic monitoring of intestinal diseases.

Skeleton Editing of Indenes With Metal Carbenes to Access 1,2‐Dihydronaphthalenes

ABSTRACT Single‐atom insertion reactions in cyclic scaffolds have garnered unprecedented attention in recent years. Despite significant advances, the direct skeleton editing of planar indene to yield three‐dimensional 1,2‐dihydronaphthalene via carbon atom insertion remains unknown. Herein, we report a silver‐catalyzed skeletal editing strategy that enables the direct insertion of a functionalized carbon atom into indenes, accessing the corresponding 1,2‐dihydronaphthalenes by trapping of an α‐trifluoromethyl arylcarbene generated from triftosylhydrazone. This transformation is operationally simple, conducted on a preparative scale, and affords products that are amenable to further derivatization. In addition, the first asymmetric single‐atom skeleton editing of indenes was accomplished by using a chiral dirhodium catalyst. Comprehensive experimental and computational studies were performed to provide detailed insights into the mechanistic pathway and the origin of enantioselectivity.

Metal-modulated phonon transport in porphyrin-based MOFs

Metal centers in porphyrin-based frameworks induce distinct thermal transport behaviors, yet their atomistic origins remain unclear. Here, first-principles calculations combined with machine-learned interatomic potentials are used to reveal lattice thermal conductivity (κ) modulation by metal incorporation in a novel 2D porphyrin framework. The results show that Zn increases κ by ∼37% and Ni reduces it by ∼35%. The mechanism is that metal incorporation changes bond uniformity and strength, which alters structural anharmonicity. The phonon relaxation time (τ) is then regulated, which ultimately tunes κ. Additionally, metal embedding enhances structural stability, which induces a blueshift of low-frequency phonons (&amp;lt;10 THz). This effect offsets the redshift induced by heavy atoms, leading to negligible group velocity changes. Specifically, Zn embedding improves bond uniformity, which prolongs τ to boost low-frequency optical mode transport. In contrast, Ni embedding causes lattice contraction and severe bond weakening, which enhances phonon anharmonicity, lowers τ, and ultimately reduces κ. This work verifies that metal selection is a key strategy for phonon engineering in low-dimensional metal-organic materials.

Main‐Group Magnesium Single‐Atom Lewis Acid Sites: A CO‐Tolerance Booster for Alkaline Hydrogen Oxidation Reaction

ABSTRACT CO poisoning is notoriously intolerable for precious metal‐based hydrogen oxidation reaction (HOR) electrocatalysts, which are significant technical barriers for anion exchange membrane fuel cells (AEMFCs). Herein, we separately constructed Lewis acid sites for CO oxidation, which can independently catalyze the oxidation of CO, maximizing the number of Ru active sites for HOR. Moreover, owing to the stable anchoring effect of Mg single atoms on the carbon substrate, ultra‐small Ru nanoparticles exhibit no agglomeration or structural changes even after cycling, maintaining excellent material structural stability. Consequently, the Ru/Mg s /C catalyst maintains high CO tolerance and excellent HOR performance. Excellent CO tolerance and recoverable performance (90% of initial activity) were demonstrated in fuel cell tests. In situ infrared spectroscopy and theoretical calculations collectively suggest that Mg single atoms, which function as Lewis acid sites, can favorably interact with Lewis base molecules such as CO and OH − via Lewis acid–base interactions, boosting the electro‐oxidation of CO and resulting in significantly enhanced HOR activity and resistance to CO‐poisoning. When assembled in AEMFCs, its specific power density is as high as 4.11 W mg −1 metal with only 0.38 mg cm −2 total platinum group metal (PGM) utilization. It also demonstrates competitive performance with ultralow precious metal loading (0.125 mg cm −2 ).

Evolution of boron nitride structures from hexagonal to cubic and wurtzite phases: A machine-learning potential approach

Boron nitride (BN) is one of the most structurally stable and widely used boron compounds. However, studies on the microscopic mechanism of three-dimensional BN synthesis have so far relied solely on static analyses, lacking direct dynamic evidence. Because the synthesis is carried out under high pressure–temperature (P–T) in a sealed environment, real-time observation is feasible but often technically challenging and costly in practice. Here, we propose the use of machine-learning potential (MLP) to overcome experimental limitations and to provide unambiguous insight into material behaviors under complex and dynamic environments. In this study, we construct a first-principles-based training dataset for BN and develop an MLP within the neuroevolution potential (NEP) framework. Comprehensive stability and reliability tests confirm that the trained NEP achieves accuracy comparable to both first-principles calculations and experimental results. Using the NEP, we perform molecular-dynamics simulations starting from different stacking configurations of two-dimensional hexagonal-BN (h-BN). The results demonstrate that, under elevated P–T conditions, h-BN precursors with any stacking motif must first undergo interlayer sliding into a specific stacking sequence before compression can yield either wurtzite-BN or cubic-BN. By systematically varying simulation conditions, we construct a critical-condition diagram for BN synthesis that closely matches experimental parameters, thereby providing valuable guidance for laboratory experiments. Our work not only offers reliable theoretical insight into BN growth but also presents an effective and generalizable approach for investigating the microscopic mechanisms of chemical processes in other materials.

Steering the Reaction Pathway of Tandem Catalytic Oxidation of HCHO Under Ambient Condition via Methanol Intermediate

ABSTRACT Tandem catalytic systems for HCHO oxidation are generally regarded as a relay process comprising intermediate (e.g., Methyl formate, MF) generation on zeolites and subsequent intermediates‐to‐CO 2 conversion on supported metal catalysts. Here, a new cascade pathway mediated by the secondary intermediate methanol (CH 3 OH) over ZSM‐5/Pt‐γ‐Al 2 O 3 tandem catalyst is proposed, which is composed of physically mixed ZSM‐5 and Pt‐γ‐Al 2 O 3 with an overall Pt content of only 0.3 wt%. In this system, the CH 3 OH is generated directly via MF decomposition on acidic ZSM‐5 and subsequently serves as the primary active intermediate on Pt‐γ‐Al 2 O 3 catalyst, enabling efficient HCHO‐to‐CO 2 complete conversion under ambient conditions. The deep studies with Pd‐ and Ag‐based tandem systems further reveal that the reaction pathway is steered by the intrinsic reactivity of intermediates on supported metal catalysts: CH 3 OH‐mediated cascade routes dominate in Pt‐ and Pd‐containing systems, whereas MF remains the sole reactive intermediate over Ag‐based tandem catalysts. Additionally, we demonstrate that the molecular diffusion of key intermediate within ZSM‐5 plays a decisive role in proximity‐dependent catalytic behavior. Specifically, the strong adsorption affinity and interfacial accumulation of CH 3 OH on ZSM‐5 necessitate close spatial proximity between the zeolite and Pt catalyst, in contrast to the weaker adsorption affinity of MF.

Retention improvement in vertical NAND flash memory using block soft erase scheme

We propose a block soft erase method to enhance the retention characteristics of vertical NAND (V-NAND) flash memory while significantly reducing soft erase time. Unlike prior incremental-step-pulse-erasing-based approaches that adjust each cell individually, the proposed method applies a single soft erase pulse to all cells simultaneously. Experimental results using commercial triple-level-cell V-NAND flash memory show that the block soft erase method enables Vth tuning across multiple program-verify levels (PVs), even under cell-to-cell variation due to word-line position and string differences. Retention characteristics measured at 85 °C demonstrated a 21.6% improvement at PV7 after 104 s.