Shield tunnel launching adjacent to a river is a typical high-risk problem in urban underground engineering. As a novel reinforcement method for launching shafts, TRD (Trench cutting Re-mixing Deep wall) has been widely applied in shield launching projects, while its stability evolution and failure mechanism remain insufficiently understood. To address this issue, a coupled theoretical model based on Mindlin's elastic solution and the rigorous limit equilibrium method is proposed for stability analysis. Considering the high computational complexity and time consumption of conventional coupled analysis methods, the XGBoost machine learning algorithm is further introduced based on the proposed theoretical model to establish a nonlinear mapping relationship between input parameters and the safety factor, thereby enabling rapid intelligent assessment of excavation stability under complex working conditions. Furthermore, the SHAP method is employed to improve the interpretability of the prediction model by identifying the contribution of different parameters to the safety factor and validating the results against theoretical sensitivity analyses. The results indicate that the shear strength reduction coefficient of the TRD-reinforced zone (ke) has the most significant influence on the safety factor, with a contribution ratio of 65%. The horizontal vibration coefficient (kc) contributes approximately 20%, while the influences of shield thrust (P) and advancement distance (L) are relatively minor. During shield advancement, the evolution of the safety factor can be divided into three stages: rapid adjustment, high-impact dominance, and low-impact stabilization. The system gradually reaches a stable state after the shield advances approximately 15m. The proposed method can provide theoretical support for the optimal design of TRD reinforcement, safety control during shield launching, and rapid on-site construction safety management.

Between the occurrence of a disaster and the initiation of formal investigation and assessment, the overall evolution of the disaster often remain unclear, which hinders the timely progress of investigative work. To address this challenge, this study proposes a framework for constructing disaster event chains from limited post-disaster information. The framework first defines event patterns based on disaster system theory, then employs the unified information extraction model to automatically extract event chain nodes and their relationships from news texts. DBSCAN clustering is further applied to achieve semantic normalization and entity standardization, enabling the reconstruction of the disaster event chain. Finally, a fuzzy comprehensive evaluation is conducted to assess the effectiveness of the proposed framework. The results demonstrate that the framework can provide valuable initial analytical insights and auxiliary support for disaster investigation efforts.

The rapid and sustainable construction of highly functionalized fluorophores remains a key challenge in organic synthesis. We detail a concise, metal-free synthetic platform for the preparation of unsymmetrical pyrrolyl-pyridine boron difluoride (BOPP) complexes from simple chalcone precursors. Central to this methodology is the optimization of a thiamine-mediated Stetter reaction under mild sonication, which efficiently generates key 1,4-diketone intermediates. Subsequent Paal-Knorr cyclization and BF3 complexation afford the desired BOPP dyes in good to excellent overall yields. This modular synthetic approach enabled facile expansion of the BOPP library, overcoming the inherent limitations of conventional cross-coupling methods. The synthesized BOPP fluorophores emit brightly in both solution and the solid state, featuring highly tunable emission profiles and large Stokes shifts of up to 88 nm. Supported by density functional theory (DFT) calculations, this study highlights the robustness of the synthetic protocol and establishes the unsymmetrical BOPP scaffold as a versatile platform for the development of next-generation fluorescent probes and functional optical materials.

Prostate-specific membrane antigen (PSMA) is a validated target for prostate cancer imaging and radiotherapy, with most high-affinity ligands incorporating the lysine-urea-glutamate (KuE) pharmacophore. Despite emerging triphosgene-free approaches, current synthetic strategies still largely rely on hypertoxic triphosgene for asymmetric urea formation. Herein, we report a comparative evaluation of triphosgene-free acyl-transfer reagents for on-resin KuE formation under solid-phase peptide synthesis (SPPS) conditions. Among the reagents examined, 1,1'-carbonyldiimidazole (CDI) emerged as the most effective, enabling near-quantitative urea formation under mild, SPPS-compatible conditions. Application of the optimised CDI-mediated protocol on TentaGel® resin bearing an HMPB linker enabled efficient fully solid-phase assembly of PSMA-617 in >80% crude purity and 31% isolated yield. Purified PSMA-617 was radiolabelled with 68Ga in >99% radiochemical purity, confirming chemical integrity. Additionally, the PSMA-I&T backbone and four PSMA-617 analogues were synthesised in high crude purities, demonstrating rapid on-resin ligand construction for structure-activity relationship (SAR) studies.

Aerobic granular sludge (AGS) technology is limited by slow granulation and structural instability. To overcome the shortcomings of existing carrier materials (e.g., activated carbon, sponge) regarding poor biocompatibility, inadequate pore connectivity, and surface chemical inertness, this study proposes a rapid AGS construction strategy based on a novel L-carrier (a renewable polymer material modified by alkali‑ultrasonic treatment to obtain hydrophilic, hierarchical porous, and high surface charge properties). Using sequencing batch reactors, the effects of the L-carrier on granulation progress, structural stability, and pollutant removal performance were systematically evaluated. Results showed that the L-carrier shortened the maturation time of the pre-formed composite granules to 5days (defined as the time required to achieve stable granule morphology, settling velocity > 70mh-1,and TN removal rate increases), representing an 80% reduction compared to conventional self-aggregation. The obtained AGS exhibited a density of 1.062g·(cm3)-1, structural integrity > 0.95, and an average settling velocity of 70.9-74.2mh-1, which are significantly superior to reported activated-carbon-assisted AGS (settling velocity 55-65mh-1) and sponge-carrier systems (integrity ≤ 0.85). COD removal exceeded 90%, and total nitrogen removal reached 70-85%, which is significantly higher than typical values reported for conventional self-aggregated AGS (TN removal 50-70%) and sponge-carrier systems (55-70%), representing a 10-15% point improvement over similar carrier-assisted systems. High-throughput microbial analysis revealed that the L-carrier surface selectively enriched genera such as Thauera, Thermomonas, and Pseudoxanthomonas (total abundance > 25%), and their EPS (extracellular polymeric substances) production (especially polysaccharides in tightly bound EPS) was 2.3 times higher than that of carrier‑free systems. In summary, the L‑carrier not only serves as a physical scaffold but also enhances granule structural integrity and functional performance by modulating the interfacial micro‑ecology, providing a new approach for engineering application of AGS.

Rapid construction and stable operation of partial nitrification-anammox in integrated fixed-film activated sludge system initiated from virgin carriers for high ammonia wastewater treatment.

An efficient copper-catalyzed (4+1) tandem annulation has been established for the rapid construction of 2,3-disubstituted benzofurans. This method converts terminal alkynes and 2-(tosylmethyl)phenols using a dual-base system, proceeding via the in situ formation of ortho-quinone methides and alkynyl-copper(I) species. Combined density functional theory calculations and control experiments elucidate a mechanism proceeding through 1,4-conjugate addition, intramolecular cyclization, and base-promoted aromatization. This transformation not only provides a novel and efficient route to functionalized benzofuran motifs but also enriches the chemistry of alkynes and o-quinone methides in organic synthesis.

Coumarins represent an important class of oxygenated heterocyclic natural products widely distributed in plants, fungi, and microorganisms. Their remarkable structural diversity ranges from simple oxygenated coumarins to complex fused architectures such as pyranocoumarins, benzocoumarins, coumestans, lamellarins, and other annulated frameworks. Because many naturally occurring coumarins are available only in limited quantities from natural sources, chemical synthesis plays a crucial role in structural confirmation, biological evaluation, and the development of functional analogues. Over the past decades, significant advances have been achieved in the synthesis of coumarin-based natural products through the development of modern synthetic methodologies. These include transition-metal-catalyzed cross-coupling reactions, C-H activation strategies, oxidative annulations, multicomponent reactions, biomimetic transformations, and cascade processes that enable the rapid construction of structurally complex coumarin frameworks. This review highlights and critically examines progress in the synthesis of naturally occurring coumarins, focusing on representative total syntheses and key transformations used to assemble diverse coumarin architectures. Particular emphasis is placed on reaction design, synthetic strategy, and methodological innovations that enable efficient access to biologically significant coumarin natural products and their derivatives.

By employing a simple and readily available chiral difluorphos ligand, a highly enantioselective rhodium-catalyzed asymmetric arylation tandem cyclization of heteroatom-containing alkyne-tethered aliphatic ketones with boronic acids was achieved under mild conditions. This protocol offers efficient and practical access to a broad spectrum of chiral heterocyclic tertiary allylic alcohols bearing trisubstituted or tetrasubstituted alkene functionality in good yields (up to 86%) with excellent enantioselectivities (up to 99% ee). Moreover, the synthetic utility of this methodology has been demonstrated via the rapid and concise construction of various structurally intriguing chiral heterocyclic architectures.

Herein, we report an iridium(I)-catalyzed C(sp3)-H bond adjacent to a nitrogen center direct alkylation of amides with terminal alkyne without an external reductant. In the presence of a cationic iridium(I) catalyst with a BiPhePhos-like ligand, this alkylation protocol allows the rapid construction of a series of corresponding alkylated products in moderate to good yields.

The first asymmetric total synthesis of Lycopodium alkaloids bearing a 1,2-amino alcohol motif, including (-)-palhinine B, (-)-palhinine C, and (+)-palhinine B, has been achieved. The synthesis features early stage installation of a chiral C2-OH group from a tyrosine-derived 1,2-amino alcohol, which governs the overall stereochemical outcome at C7, C13, C15, and a quaternary stereogenic center at C12 of the tetracyclic palhinine skeleton. A highly diastereoselective Diels-Alder reaction of a masked ortho-benzoquinone, followed by a thiol-mediated acyl radical cyclization, enables rapid construction of the isotwistane core. DFT-guided analysis revealed the challenge of late-stage C2-OH inversion and led to a successful chemo- and diastereoselective reduction of a caged hemiaminal ketone, providing access to the C2 epimer. This work establishes a unified asymmetric strategy for complex Lycopodium alkaloids and highlights the integration of computation with synthetic design.

A general and efficient strategy for the synthesis of maleimides from readily accessible ynamides and α-ketoesters via in situ generated lithiated ketenimines, engaging in a cascade sequence involving formal anionic (2 + 2) cycloaddition, cycloreversion, and cyclocondensation, is reported. This method enables rapid access to a wide range of densely functionalized maleimides with excellent functional group tolerance, under conditions allowing either retention or removal of the N-protecting group. The resulting scaffolds can be readily diversified, notably through a "nitrogen switch" strategy, to access distinct heterocycles. The power of this approach is demonstrated in the concise syntheses of denigrin A and aqabamycin A, as well as the first unified and divergent synthesis of antrodins A-C, highlighting its potential as a versatile platform for the rapid construction of functional maleimide architectures.

Strain-release difunctionalization of [1.1.1]propellane has emerged as a powerful strategy for the construction of benzene bioisosteres. Herein, we report a copper-catalyzed alkylative alkynylation of [1.1.1]propellanes with terminal alkynes and cyclobutanone oxime esters. This transformation proceeds under mild photocatalyst- and ligand-free conditions, providing a cost-effective and practical alternative to existing photoredox-based systems. The reaction features broad substrate scope and good functional group tolerance and is applicable to the late-stage modification of complex molecules. Importantly, this protocol can be extended to [3.1.1]propellane, providing efficient access to alkynylated bicyclo[3.1.1]heptanes as valuable meta-benzene bioisosteres. Given the versatility of both alkynyl and cyano functionalities, this method offers a practical platform for the rapid construction and diversification of bicycloalkane scaffolds.

Rapid construction of self-supporting 3D network and enhancement of thermal conductivity in OH-BN/RTV system

The reductive dicarbofunctionalization of alkenes represents a powerful platform for the rapid construction of complex motifs from abundant materials by forging two chemical bonds in a single operation. Despite significant progress, the use of excessive reductants remains largely limited to environmentally unfriendly metal reductants or pyrophoric/expensive organic reductants, which may lead to serious environmental pollution, high costs, and low functional group tolerance. By leveraging NaI, rarely employed as a reductant in coupling reactions, we developed a novel reductive aminomethylcyanoalkylation of alkenes accelerated by iron electron-shuttle catalysis, allowing for the synthesis of sterically congested amino nitriles, valuable yet synthetically challenging motifs in organic synthesis. Mechanistic studies further confirmed that sodium iodide serves as the decisive terminal reductant.

Pyranocoumarins are widely distributed in natural products and exhibit intriguing biological activities, making their efficient synthesis highly desirable. Herein, we developed an efficient method for synthesizing two new types dimethylallyl-decorated pyranocoumarins in efficiency through catalytic formal [3 + 3] annulation of 4-hydroxycoumarins with valylene. Under acid catalysis, exclusive 1,3-alkenoxylation afforded natural product-like angular pyranocoumarins, while Rh catalysis switched regioselectivity to 3,1-alkenoxylation. The protocol features high atom-economy, readily available substrates, and excellent regio- and chemo-selectivity. Mechanistic studies indicated the reaction proceeds via regioselective hydroalkoxylation to form diene or allene intermediates, followed by intramolecular cyclization. This work not only represents a good paradigm in addressing selectivity challenges in reactions involving substrates with multireactive-site but also offers a robust platform for rapid construction of skeletal variants beyond naturally occurring structures.

To enable the rapid generation of subject-specific whole-body anatomical models for patient-specific prediction of torso-local specific absorption rate (SAR) in MRI. A 6-s 3D gradient-echo MRI sequence was used to acquire data within the imaging field of view (FOV). Major tissue types were automatically segmented using a deep learning model trained via a semi-supervised strategy combining teacher-student learning and partial-category annotations. A full-body geometry was reconstructed from depth data captured by a 3D camera, thereby extending the model beyond the FOV. The MRI-derived anatomical segmentation and camera-based external geometry were co-registered and fused into a seamless, subject-specific human model. Human models were generated in approximately 20 s per subject, including MRI acquisition and processing. Accurate tissue segmentation and robust body reconstruction were achieved. Validation on the Duke numerical phantom yielded an average peak SAR10g error < 2%. In vivo field comparisons in 20 volunteers showed a normalized root-mean-square error (NRMSE) of 9.50%. The models preserved subject-specific anatomy and were suitable for electromagnetic simulation. A hybrid framework integrating ultrafast MRI, depth data scanning and deep learning enables rapid construction of subject-specific human models, supporting practical, online SAR monitoring in clinical MRI.

We have developed an efficient and concise synthetic strategy for the rapid construction of morpholine-fused bicyclic scaffolds under mild aerobic conditions via Pd(II)-catalyzed oxidative cyclization of 1,3-cyclohexadiene with amino alcohol substrates. This protocol enables direct 1,2-aminooxygenation of cyclic dienes, providing access to a range of fused morpholine derivatives with good regioselectivity and yields.

Bicyclo[1.1.0]butanes (BCBs) are among the smallest and most strained carbocycles and have emerged as powerful synthetic building blocks in modern organic chemistry. Recent years have witnessed a surge of interest in understanding and exploiting their unique reactivity. The high strain energy associated with the central C-C bond enables a variety of transformations, including insertions, additions, cycloadditions, and molecular rearrangements, often proceeding under mild conditions. This inherent strain facilitates the rapid and efficient construction of diverse and complex molecular architectures. Moreover, the incorporation of BCB motifs as bioisosteres of benzene derivatives has drawn significant attention in medicinal chemistry, owing to their high sp3 character and three-dimensionality. In this review, we summarize the important structural features and the recent advances in the reactivity of BCBs, highlighting key developments, mechanistic insights and the associated modes of reactivity explored.

Here, we report a mild and DNA-compatible cyclization strategy for the construction of [1,2,4]triazolo[1,5-a]pyridine scaffolds that is well suited for DNA-encoded library (DEL) construction. This reaction proceeds via cyclocondensation of aldehydes with 1,2-diaminopyridinium salt substrates under mild and simple conditions. This method enables the rapid and efficient construction of a series of DNA-encoded libraries containing compounds with a potentially biologically active [1,2,4]triazolo[1,5-a]pyridine scaffold.