Synthesis of Dienamides via Palladium-catalyzed Oxidative N-α,ß-Dehydrogenation of Amides.

Enamides and their derivatives are prominent bioactive pharmacophores found in various bioactive molecules. Herein we report a palladium-catalyzed oxidative N-α,ß-dehydrogenation of amides to produce a range of enamides with high yields and excellent tolerance toward different functional groups. Mechanistic studies indicate that the reaction involves allylic C(sp3)-H activation followed by ß-H elimination. The effectiveness of this approach is demonstrated through late-stage functionalization of bioactive molecules and the synthesis of valuable compounds through product elaboration.

Tetris-inspired detector with neural network for radiation mapping.

Radiation mapping has attracted widespread research attention and increased public concerns on environmental monitoring. Regarding materials and their configurations, radiation detectors have been developed to identify the position and strength of the radioactive sources. However, due to the complex mechanisms of radiation-matter interaction and data limitation, high-performance and low-cost radiation mapping is still challenging. Here, we present a radiation mapping framework using Tetris-inspired detector pixels. Applying inter-pixel padding for enhancing contrast between pixels and neural networks trained with Monte Carlo (MC) simulation data, a detector with as few as four pixels can achieve high-resolution directional prediction. A moving detector with Maximum a Posteriori (MAP) further achieved radiation position localization. Field testing with a simple detector has verified the capability of the MAP method for source localization. Our framework offers an avenue for high-quality radiation mapping with simple detector configurations and is anticipated to be deployed for real-world radiation detection.

Numerical simulation of rock blasting under different in-situ stresses and joint conditions.

High primary rock stress can limit the generation of rock cracks caused by blasting, and blasting usually shows different rock breaking states under different primary rock stress conditions. There are a large number of naturally formed joints in rock mass, due to the limitations of laboratory tests, a numerical model of jointed rock mass was established using LS-DYNA software to investigate the evolution of blasting damage under various in-situ stresses and open joints. In this simulation, using the Lagrange-Euler (ALE) procedure and the equation of state (JWL) that defines explosive materials, the study considered different joint thicknesses (2cm, 4cm, and 6cm), joint angles (0°, 30°, 60°, and 90°), and in-situ stress conditions (lateral stress coefficients of 0.5, 1, and 2, with vertical in-situ stresses of 10MPa and 20MPa), through stress analysis and damage area comparison, the relationship between damage crack propagation and horizontal and vertical stress difference is explored. The research aimed to understand the mechanisms underlying crack initiation and propagation. The results show that: (1) The presence of joints exerts a barrier effect on the expansion and penetration of cracks. When explosion stress waves reach the joint surface, their propagation is impeded, leading to the diffusion of wing cracks at the joint ends. When the lateral stress coefficient and joint angle are the same, an increase in initial in-situ stress results in a reduction in the area of the blasting damage zone. (2) Under the same initial in-situ stress conditions, the area of the blasting damage zone initially increases and then decreases with an increasing joint angle. However, it remains larger than that without a joint, and there exists an optimal angle that maximizes the damage area. In the simulated conditions, the area of damage cracks is greatest when the joint angle is 60° dip angle. (3) The presence of initial in-situ stress has a certain impact on the initiation and expansion of blasting cracks. The degree and nature of this influence are not solely related to the lateral stress coefficient but also depend on the joint's angle and thickness. When in-situ stress is present, the initial in-situ stress field's pressure is not conducive to the initiation and propagation of blasting cracks. However, the existence of a joint has a noticeable guiding and promoting effect on crack propagation, and the pattern of crack propagation is influenced by both joint and in-situ stress conditions.

Field-free deterministic switching of all-van der Waals spin-orbit torque system above room temperature.

Two-dimensional van der Waals (vdW) magnetic materials hold promise for the development of high-density, energy-efficient spintronic devices for memory and computation. Recent breakthroughs in material discoveries and spin-orbit torque control of vdW ferromagnets have opened a path for integration of vdW magnets in commercial spintronic devices. However, a solution for field-free electric control of perpendicular magnetic anisotropy (PMA) vdW magnets at room temperatures, essential for building compact and thermally stable spintronic devices, is still missing. Here, we report a solution for the field-free, deterministic, and nonvolatile switching of a PMA vdW ferromagnet, Fe3GaTe2, above room temperature (up to 320 K). We use the unconventional out-of-plane anti-damping torque from an adjacent WTe2 layer to enable such switching with a low current density of 2.23 × 106 A cm-2. This study exemplifies the efficacy of low-symmetry vdW materials for spin-orbit torque control of vdW ferromagnets and provides an all-vdW solution for the next generation of scalable and energy-efficient spintronic devices.

Current-induced switching of a van der Waals ferromagnet at room temperature.

Recent discovery of emergent magnetism in van der Waals magnetic materials (vdWMM) has broadened the material space for developing spintronic devices for energy-efficient computation. While there has been appreciable progress in vdWMM discovery, a solution for non-volatile, deterministic switching of vdWMMs at room temperature has been missing, limiting the prospects of their adoption into commercial spintronic devices. Here, we report the first demonstration of current-controlled non-volatile, deterministic magnetization switching in a vdW magnetic material at room temperature. We have achieved spin-orbit torque (SOT) switching of the PMA vdW ferromagnet Fe3GaTe2 using a Pt spin-Hall layer up to 320 K, with a threshold switching current density as low as [Formula: see text]1.69 [Formula: see text] 106 A cm-2 at room temperature. We have also quantitatively estimated the anti-damping-like SOT efficiency of our Fe3GaTe2/Pt bilayer system to be [Formula: see text], using the second harmonic Hall voltage measurement technique. These results mark a crucial step in making vdW magnetic materials a viable choice for the development of scalable, energy-efficient spintronic devices.

Preparation of high-performance monoazo disperse dyes bearing ester groups based on benzisothiazole and their dyeing performance on polyester fabrics.

To obtain high-performance disperse dyes, a series of azo disperse dyes containing different kinds of ester groups based on benzisothiazole were synthesized by the coupling reaction of diazotization of 3-amino-5-nitro [2,1] benzisothiazole with N-substituted aniline compounds bearing different ester moieties. The structures of the synthesized dyes were evaluated using Fourier transform infrared spectroscopy (FT-IR), nuclear magnetic resonance techniques (1H-NMR), and MS analysis. UV-Vis spectrophotometry methods were applied to study absorption maxima, molar extinction coefficients, and solvatochromic behaviors of the dyes, and time-dependent density functional theory (TD-DFT) simulations were applied to reveal the nature of the absorption spectrum properties. Polyester fabrics were colored using a high-temperature dyeing method under pressure, and the dyed fabrics exhibited deep and bright intense blue hues. In addition, excellent fastness properties, including washing fastness, sublimation fastness, rubbing fastness, and light fastness, were achieved.

Integrating network pharmacology and experimental verification to explore the mucosal protective effect of Chimonanthus nitens Oliv. Leaf Granule on ulcerative colitis.

ETHNOPHARMACOLOGICAL RELEVANCE: Chimonanthus nitens Oliv. Leaf Granule (COG) is a commonly used clinical preparation of traditional Chinese medicine for the treatment of cold, but there are folk reports that it can treat diarrhea and other gastrointestinal diseases. Therefore, the mechanism of COG in the treatment of ulcerative colitis with diarrhea as the main symptom needs to be studied. AIM OF THE STUDY: Combined network pharmacology and experimental validation to explore the mechanism of COG in the treatment of ulcerative colitis. MATERIALS AND METHODS: First, the main components of COG were characterized by liquid chromatography-mass spectrometry (LC-MS); subsequently, a network pharmacology approach was used to screen the effective chemical components and action targets of COG to construct a target network of COG for the treatment of ulcerative colitis (UC). The protein-protein interaction network (PPI) and literature reports were combined to identify the potential targets of COG for the treatment of UC. Finally, the predicted results of network pharmacology were validated by animal and cellular experiments. RESULTS: 19 components of COG were characterized by LC-MS, among which 10 bioactive components could act on 377 potential targets of UC. Key therapeutic targets were collected, including SRC, HSP90AA1, PIK3RI, MAPK1 and ESR1. KEGG results are enriched in pathways related to oxidative stress. Molecular docking analysis showed good binding activity of main components and target genes. Animal experiments showed that COG significantly relieved the colitis symptoms in mice, regulated the Treg/Th17 balance, and promoted the secretion of IL-10 and IL-4, along with the inhibition of IL-1ß and TNF-α. Additionally, COG reduced the apoptosis of colon epithelial cells, and significantly improved the levels of SOD, MAO, GSH-px, and inhibited MDA, iNOS, eNOS in colon. Also, it increased the expression of tight junction proteins such as ZO-1, Claudin1, Occludin and E-cadherin. In vitro experiments, COG inhibited the oxidative stress and inflammatory injury of HCT116 cells induced by LPS. CONCLUSIONS: Combining network pharmacology and in vitro and in vivo experiments, COG was verified to have a good protective effect in UC, which may be related to enhancing antioxidation in colon tissues.

Three-dimensional flat bands in pyrochlore metal CaNi2.

Electronic flat-band materials host quantum states characterized by a quenched kinetic energy. These flat bands are often conducive to enhanced electron correlation effects and emergent quantum phases of matter1. Long studied in theoretical models2-4, these systems have received renewed interest after their experimental realization in van der Waals heterostructures5,6 and quasi-two-dimensional (2D) crystalline materials7,8. An outstanding experimental question is if such flat bands can be realized in three-dimensional (3D) networks, potentially enabling new materials platforms9,10 and phenomena11-13. Here we investigate the C15 Laves phase metal CaNi2, which contains a nickel pyrochlore lattice predicted at a model network level to host a doubly-degenerate, topological flat band arising from 3D destructive interference of electronic hopping14,15. Using angle-resolved photoemission spectroscopy, we observe a band with vanishing dispersion across the full 3D Brillouin zone that we identify with the pyrochlore flat band as well as two additional flat bands that we show arise from multi-orbital interference of Ni d-electrons. Furthermore, we demonstrate chemical tuning of the flat-band manifold to the Fermi level that coincides with enhanced electronic correlations and the appearance of superconductivity. Extending the notion of intrinsic band flatness from 2D to 3D, this provides a potential pathway to correlated behaviour predicted for higher-dimensional flat-band systems ranging from tunable topological15 to fractionalized phases16.

A multi-dimensional fusion strategy similarity measure method for patent application technology disclosure document.

Patent application technology disclosure document is one of the important bases for judging patent novelty and uniqueness. Automated evaluation can effectively solve the problems of long time and strong subjectivity of human evaluation. The text similarity evaluation algorithm based on corpus and deep learning technology has problems such as insufficient amount of cross-library learning data and insufficient core content tendency in the similarity judgment of patent application technology disclosure document, which limits their performance and practical application. In this paper, we propose a similarity evaluation method of patent application technology disclosure document based on multi-dimensional fusion strategy to realize the similarity measurement of patents. Firstly, in the text preprocessing section, word segmentation reconstruction and similarity evaluation optimization strategies based on word frequency and part-of-speech score weighted fusion are proposed. Then, a similarity calculation method of patent application technology disclosure document based on two new mapping spaces of dot matrix and image is proposed to achieve a more diversified comprehensive evaluation. The algorithm was evaluated by using four published text similarity matching datasets (containing 0-5 or 0/1 labels) and a set of patent application technology disclosure documents. Experimental results show that on the published text similarity matching datasets, the similarity evaluation method under the multi-dimensional fusion strategy proposed in this paper has a discrimination accuracy improvement of about 10% compared to traditional vector semantic model, and can match the discriminative ability of lightweight deep learning models without the need for training. At the same time, the discrimination accuracy of the proposed method on the sample dataset of patent application technology disclosure document is superior to traditional vector semantic model (20%) and various deep learning models (1%-8%), and the precision and recall rate are relatively balanced. The visual analysis results on the dataset of the patent application technology disclosure documents also prove the effectiveness and reliability of the similarity calculation method proposed in the dot matrix and image space, which provide a new idea and method for the similarity evaluation between patent application technology disclosure document.

Topology stabilized fluctuations in a magnetic nodal semimetal.

The interplay between magnetism and electronic band topology enriches topological phases and has promising applications. However, the role of topology in magnetic fluctuations has been elusive. Here, we report evidence for topology stabilized magnetism above the magnetic transition temperature in magnetic Weyl semimetal candidate CeAlGe. Electrical transport, thermal transport, resonant elastic X-ray scattering, and dilatometry consistently indicate the presence of locally correlated magnetism within a narrow temperature window well above the thermodynamic magnetic transition temperature. The wavevector of this short-range order is consistent with the nesting condition of topological Weyl nodes, suggesting that it arises from the interaction between magnetic fluctuations and the emergent Weyl fermions. Effective field theory shows that this topology stabilized order is wavevector dependent and can be stabilized when the interband Weyl fermion scattering is dominant. Our work highlights the role of electronic band topology in stabilizing magnetic order even in the classically disordered regime.

Spherulitic Crystallization of CsCu2I3 for High Performance Ultraviolet Photodetectors.

Ternary copper halides have become promising materials for UV photodetection due to their stability and eco-friendliness. However, the uncontrollable crystallization induces high-concentration defects in these films, inherently limiting further improvement in device performance. Herein, we reveal the antisolvent-assisted crystallization kinetics mechanism of CsCu2I3 during the film-forming process. The nucleation rate is manipulated by adjusting precursor supersaturation using different antisolvents, resulting in decreased density and preferential orientation of the nuclei within the wet film. Subsequent annealing leads to a homogeneous and low-defect CsCu2I3 film with 40-µm-scale spherulites. A resulting visible-blind ultraviolet photodetector exhibits a responsivity of 8.73 A W-1, a specific detectivity of 5.28 × 1012 jones, and a response speed of 1.12 ms. The unencapsulated photodetector shows negligible degradation of responsivity in ambient air (∼70% humidity) for one month. Moreover, the flexible device with a responsivity of 420.2 mA W-1 and a detectivity of 1.18 × 1012 jones also shows excellent bending stability.

Topological Superconductors from a Materials Perspective.

Topological superconductors (TSCs) have garnered significant research and industry attention in the past two decades. By hosting Majorana bound states which can be used as qubits that are robust against local perturbations, TSCs offer a promising platform toward (nonuniversal) topological quantum computation. However, there has been a scarcity of TSC candidates, and the experimental signatures that identify a TSC are often elusive. In this Perspective, after a short review of the TSC basics and theories, we provide an overview of the TSC materials candidates, including natural compounds and synthetic material systems. We further introduce various experimental techniques to probe TSCs, focusing on how a system is identified as a TSC candidate and why a conclusive answer is often challenging to draw. We conclude by calling for new experimental signatures and stronger computational support to accelerate the search for new TSC candidates.

Witnessing light-driven entanglement using time-resolved resonant inelastic X-ray scattering.

Characterizing and controlling entanglement in quantum materials is crucial for the development of next-generation quantum technologies. However, defining a quantifiable figure of merit for entanglement in macroscopic solids is theoretically and experimentally challenging. At equilibrium the presence of entanglement can be diagnosed by extracting entanglement witnesses from spectroscopic observables and a nonequilibrium extension of this method could lead to the discovery of novel dynamical phenomena. Here, we propose a systematic approach to quantify the time-dependent quantum Fisher information and entanglement depth of transient states of quantum materials with time-resolved resonant inelastic x-ray scattering. Using a quarter-filled extended Hubbard model as an example, we benchmark the efficiency of this approach and predict a light-enhanced many-body entanglement due to the proximity to a phase boundary. Our work sets the stage for experimentally witnessing and controlling entanglement in light-driven quantum materials via ultrafast spectroscopic measurements.

Biosynthesis of 1,3-Propanediol via a New Pathway from Glucose in Escherichia coli.

1,3-Propanediol (1,3-PDO), an important dihydric alcohol, is widely used in textiles, resins, and pharmaceuticals. More importantly, it can be used as a monomer in the synthesis of polytrimethylene terephthalate (PTT). In this study, a new biosynthetic pathway is proposed to produce 1,3-PDO using glucose as a substrate and l-aspartate as a precursor without the addition of expensive vitamin B12. We introduced a 3-HP synthesis module derived from l-aspartate and a 1,3-PDO synthesis module to achieve the de novo biosynthesis. The following strategies were then pursued that included screening key enzymes, optimizing the transcription and translation levels, enhancing the precursor supply of l-aspartate and oxaloacetate, weakening the tricarboxylic acid (TCA) cycle, and blocking competitive pathways. We also used transcriptomic methods to analyze the different gene expression levels. Finally, an engineered Escherichia coli strain produced 6.41 g/L 1,3-PDO with a yield of 0.51 mol/mol glucose in a shake flask and 11.21 g/L in fed-batch fermentation. This study provides a new pathway for production of 1,3-PDO.

Palladium-Catalyzed Oxidative Amination of Unactivated Olefins with Primary Aliphatic Amines.

Direct coupling of unactivated olefins with primary alkylamines is considered to be an efficient but unknown method for the construction of complex amines. Herein we report a catalytic intermolecular oxidative amination of unactivated olefins with primary aliphatic amines based on the combination of a palladium catalyst, a bidentate phosphine ligand, and duroquinone. A range of secondary allylic amines were obtained in good yields with excellent regio- and stereoselectivity. Mechanistic control experiments revealed that the reaction proceeds by allylic C(sp3)-H activation and nucleophilic amination. The utility of the protocol is further demonstrated with the late-stage modification and streamlined synthesis of drug molecules.

The Effect of Embedded Nanoparticles on the Phonon Spectrum of Ice: An Inelastic X-ray Scattering Study.

As a contribution to the ongoing effort toward high-frequency sound manipulation in composite materials, we use Inelastic X-ray Scattering to probe the phonon spectrum of ice, either in a pure form or with a sparse amount of nanoparticles embedded in it. The study aims at elucidating the ability of nanocolloids to condition the collective atomic vibrations of the surrounding environment. We observe that a nanoparticle concentration of about 1 % in volume is sufficient to visibly affect the phonon spectrum of the icy substrate, mainly canceling its optical modes and adding nanoparticle phonon excitations to it. We highlight this phenomenon thanks to the lineshape modeling based on a Bayesian inference, which enables us to capture the finest detail of the scattering signal. The results of this study can empower new routes toward the shaping of sound propagation in materials through the control of their structural heterogeneity.

One dimensional wormhole corrosion in metals.

Corrosion is a ubiquitous failure mode of materials. Often, the progression of localized corrosion is accompanied by the evolution of porosity in materials previously reported to be either three-dimensional or two-dimensional. However, using new tools and analysis techniques, we have realized that a more localized form of corrosion, which we call 1D wormhole corrosion, has previously been miscategorized in some situations. Using electron tomography, we show multiple examples of this 1D and percolating morphology. To understand the origin of this mechanism in a Ni-Cr alloy corroded by molten salt, we combined energy-filtered four-dimensional scanning transmission electron microscopy and ab initio density functional theory calculations to develop a vacancy mapping method with nanometer-resolution, identifying a remarkably high vacancy concentration in the diffusion-induced grain boundary migration zone, up to 100 times the equilibrium value at the melting point. Deciphering the origins of 1D corrosion is an important step towards designing structural materials with enhanced corrosion resistance.

Panoramic Mapping of Phonon Transport from Ultrafast Electron Diffraction and Scientific Machine Learning.

One central challenge in understanding phonon thermal transport is a lack of experimental tools to investigate frequency-resolved phonon transport. Although recent advances in computation lead to frequency-resolved information, it is hindered by unknown defects in bulk regions and at interfaces. Here, a framework that can uncover microscopic phonon transport information in heterostructures is presented, integrating state-of-the-art ultrafast electron diffraction (UED) with advanced scientific machine learning (SciML). Taking advantage of the dual temporal and reciprocal-space resolution in UED, and the ability of SciML to solve inverse problems involving O ( 10 3 ) $\mathcal{O}({10^3})$ coupled Boltzmann transport equations, the frequency-dependent interfacial transmittance and frequency-dependent relaxation times of the heterostructure from the diffraction patterns are reliably recovered. The framework is applied to experimental Au/Si UED data, and a transport pattern beyond the diffuse mismatch model is revealed, which further enables a direct reconstruction of real-space, real-time, frequency-resolved phonon dynamics across the interface. The work provides a new pathway to probe interfacial phonon transport mechanisms with unprecedented details.

M-STAR: Magnetism second target advanced reflectometer at the Spallation Neutron Source.

M-STAR is a next generation polarized neutron reflectometer with advanced capabilities. A new focusing guide concept is optimized for samples with dimensions down to a millimeter range. A proposed hybrid pulse-skipping chopper will enable experiments at constant geometry at one incident angle in a broad range of wavevector transfer Q up to 0.3 A-1 for specular, off-specular, and GISANS measurements. M-STAR will empower nanoscience and spintronics studies routinely on small samples (∼2 × 2 mm2) and of atomic-scale thickness using versatile experimental conditions of magnetic and/or electric fields, light, and temperature applied in situ to novel complex device-like nanosystems with multiple buried interfaces. M-STAR will enable improved grazing incidence diffraction measurements, as a surface-sensitive depth-resolved probe of, e.g., the out-of-plane component of atomic magnetic moments in ferromagnetic, antiferromagnetic, and more complex structures as well as in-plane atomic-scale structures inaccessible with contemporary diffractometry and reflectometry. New horizons will be opened by the development of an option to probe near-surface dynamics with inelastic grazing incidence scattering in the time-of-flight mode. These novel options in combination with ideally matched parameters of the second target station will place M-STAR in the world's leading position for high resolution polarized reflectometry.

Machine-Learning Spectral Indicators of Topology.

Topological materials discovery has emerged as an important frontier in condensed matter physics. While theoretical classification frameworks have been used to identify thousands of candidate topological materials, experimental determination of materials' topology often poses significant technical challenges. X-ray absorption spectroscopy (XAS) is a widely used materials characterization technique sensitive to atoms' local symmetry and chemical bonding, which are intimately linked to band topology by the theory of topological quantum chemistry (TQC). Moreover, as a local structural probe, XAS is known to have high quantitative agreement between experiment and calculation, suggesting that insights from computational spectra can effectively inform experiments. In this work, computed X-ray absorption near-edge structure (XANES) spectra of more than 10 000 inorganic materials to train a neural network (NN) classifier that predicts topological class directly from XANES signatures, achieving F1 scores of 89% and 93% for topological and trivial classes, respectively is leveraged. Given the simplicity of the XAS setup and its compatibility with multimodal sample environments, the proposed machine-learning-augmented XAS topological indicator has the potential to discover broader categories of topological materials, such as non-cleavable compounds and amorphous materials, and may further inform field-driven phenomena in situ, such as magnetic field-driven topological phase transitions.