Agricultural intensification accelerates soil erosion and eutrophication, yet its role in regulating toxic metal accumulation and chemical speciation in lake sediments remains poorly understood. This study deciphers the linkages between the spatiotemporal trajectories of As, Cd, Cr, Cu, Ni, Pb and Zn in Qilu Lake, a eutrophic plateau lake in southwest China, by analyzing six sediment cores and fourteen surface sediments. Results indicate a clear metal regime shift since the 1980s, characterized by decreasing total metal concentrations. This trend was attributed to sediment coarsening, primarily resulting from lake drainage for cropland expansion. However, enrichment factor analysis identified enhanced As, Cd, Pb and Zn contamination since the 1980s, peaking in the 2000s with Cd and Pb reaching heavy contamination levels primarily tied to agricultural non-point sources. Spatially, the western lake areas adjacent to intensive agricultural watersheds exhibited amplified contamination. Critically, chemical speciation analysis revealed that 81% of Cd in surface sediments occurred in bioavailable forms, followed by Zn (58%) and Cu (45%). The percentages of all metals in oxidizable form were markedly elevated compared to background levels, indicating enhanced metal-organic matter associations under eutrophic conditions. Integrating sediment quality guidelines, potential ecological risk index and chemical speciation strengthened the rigor of the risk assessment, identifying Cd as the sole high-risk metal. Other metals, while currently low-risk, may pose elevated mobilization risks under physical disturbances. This work advances the understanding of agricultural intensification as a dual geochemical engine reshaping both the abundance and biogeochemical behavior of metals in addition to driving eutrophication.
Euphorbia milii Des Moul is a plant with a long history of use in traditional medicinal and is widely distributed across tropical and subtropical regions. Traditionally, its sap has been used in folk medicine to treat various conditions such as skin inflammations, pain, and boils. To date, it remains a commonly used herbal medicine in clinical practice. This paper systematically reviews the phytochemistry, pharmacology and toxicology of E. milii to assess its therapeutic potential and guide future studies. A comprehensive literature search was performed based on multiple s databases, including Web of Science, ScienceDirect, PubMed, Elsevier, CNKI, VIP, and Wanfang. Additionally, taxonomic databases such as Flora of China and Plants of the World Online (POWO) were consulted to verify the plant's nomenclature and distribution. To date, 85 compounds have been identified from E. milii, comprising 74 diterpenoids, 6 triterpenoids, 2 steroids, 2 flavonoids, and 1 macrocyclic lactone. These phytochemicals exhibit a broad spectrum of pharmacological activities, including analgesic, anti-inflammatory, antioxidant, antimicrobial, anticancer, anti-gout, molluscicide, and anti-parasitic effects. Given its long history of traditional use, rich phytochemical composition, and diverse pharmacological activities, E. milii can be considered an important botanical resource for applications not only in traditional medicine but also in modern ecological and potential pharmacological contexts. However, in vivo and clinical studies remain limited. Future research should emphasize pharmacokinetic profiling to strengthen the basis for clinical applications and new drug development.
In this study, a novel strategy integrating aptamer-gated cell-free synthetic biology with electrochemical analysis has been developed for thrombin detection (using thrombin as a model target). A DNA template embedded with a target-specific aptamer is designed as a "molecular switch". Target binding induces a conformational change in the aptamer, creating steric hindrance for T7 RNA polymerase and thereby inhibiting transcription of the RNA reporter strand. The transcribed RNA can hybridize with methylene blue (MB)-labeled DNA probes immobilized on the electrode surface, causing electroactive species to move away from the electrode surface and resulting in a relatively low electrochemical signal. Conversely, a reduced amount of transcribed RNA leads to an increased electrochemical signal. Under optimized conditions, the biosensor exhibits a linear range of 0.06 nM - 6 μM and a limit of detection (LOD) of 0.032 nM (S/N = 3). The sensor demonstrates excellent specificity against interfering proteins. Spike-recovery tests in 20-fold diluted human serum yield recoveries of 95.35% - 105.20% with RSD values of 2.32% - 4.90%, confirming its anti-interference ability in complex biological matrices. This methodological innovation realizes sensitive and specific detection of thrombin and provides a generalizable strategy for cell-free electrochemical analysis of protein targets. By replacing the aptamer sequence, the platform can be extended to diverse proteins, opening new avenues for the application of cell-free synthetic biology in biosensing and clinical diagnostics.
Alkene 1,1-difunctionalization holds significant importance in organic synthesis due to its ability to effectively enhance the complexity and functionality of molecular frameworks. Herein, we report an electrochemical strategy for 1,1-difunctionalization of halogenated aromatics with unactivated alkenes using synergistic Fe/Ni catalysis. This system integrates redox activity of nickel with Lewis acid functionality of iron: the nickel catalyst governs aryl halide oxidative addition and alkene migration, while iron species activates catalytic sites, stabilizes radical acceptors, and precisely regulates electrochemical reduction sequences/selectivities. The reaction system is applicable to a wide range of substrates, including electron-rich and electron-deficient aryl halides, polycyclic compounds, and bioactive natural products (100 examples). Gram-scale synthesis maintains 63% yield, supporting industrial viability. Mechanistic studies elucidate the unique cooperativity of this iron-nickel bimetallic system, providing a theoretical framework for the design of diverse difunctionalization reactions.
Phenolic compounds are highly susceptible to degradation during processing and storage, which limits their application in food systems. However, the role of extraction-derived composition in governing encapsulation performance and stability remains poorly understood. This study investigated how phenolic composition obtained through percolation influences the structural, physicochemical, and thermal properties of maltodextrin-based microcapsules produced by spray drying. High encapsulation efficiency (87%) was achieved; however, compound-dependent losses were observed, including reductions of 43.73% for chlorogenic acid and 52.09% for quercetin under specific storage conditions. Encapsulation improved the retention of volatile compounds and enhanced thermal stability, shifting degradation events to higher temperatures. FTIR analysis revealed intermolecular interactions between phenolic compounds and the carbohydrate matrix, while SEM confirmed the formation of spherical particles typical of spray-dried systems. XRD and thermal analyses indicated predominantly amorphous structures associated with reduced molecular mobility. These results demonstrate that compound retention is governed by molecular structure and matrix interactions rather than apparent antioxidant activity. Overall, this study provides mechanistic insights into structure-mobility-stability relationships and supports the rational design of carbohydrate-based delivery systems for improved bioactive stability.
Monolayer molybdenum disulfide (MoS2) is one of the most studied two-dimensional materials. While the thermodynamically stable and well-investigated state of monolayer MoS2 is the semiconducting 1H phase, it can also exist in the 1T' phase, which exhibits semimetallic characteristics and topologically protected properties. However, scalable postsynthetic methods to achieve and stabilize the 1T' phase remain elusive, as monolayer MoS2 selectively reverts to the 1H phase under thermal equilibrium. In this study, we present a strategy to induce, stabilize, and spatially define the 1T' phase in monolayer MoS2 synthesized via chemical vapor deposition (CVD). By employing a sequential oxidation process followed by polymer enwrapment, we successfully converted CVD-grown monolayer MoS2 from the 1H phase to the 1T' phase. Transport measurements reveal a weak gate dependence, consistent with the semimetallic nature of the 1T' phase. Our results further demonstrate that interfacial interactions with the polymer play a critical role in both facilitating the conversion and stabilization of the 1T' monolayer MoS2. The phase conversion from 1H to 1T' induces significant structural rearrangements, leading to the formation of nanoscale wrinkles in the monolayer flake. The lateral size of the 1T' domains is estimated to be approximately 100-200 nm, suggesting that an in-plane strain of approximately 1% is introduced during the oxidation process. This strain is effectively stabilized by the polymer interface. The entire treatment is carried out under ambient conditions at room temperature, providing a simple and scalable approach to phase engineering in two-dimensional materials.
Macromolecular crowding plays a pivotal role in shaping protein stability and bridges insights from in vitro studies to the cellular environment. We investigated the stability of CRABP I through urea melt studies in the presence of PEG 2000 and PEG 4000, monitoring fluorescence wavelength shifts as sensitive indicators of structural transitions. In the absence of crowding agents, CRABP I unfolded with Cm at 4.39 M urea, whereas both PEG variants shifted the unfolding transition to higher concentrations, indicating an enhanced stability. This stabilization reflects crowding-induced reshaping of the free energy landscape, where excluded-volume effects entropically favor the native compact state. PEG 4000, with its larger size, imposed stronger steric constraints and augmented preferential hydration, thereby reinforcing intramolecular interactions and restricting the access of urea to the hydrophobic core. Complementary molecular dynamics simulations corroborated these mechanisms, highlighting how macromolecular crowding governs protein folding pathways and stability under physiologically relevant conditions.
This work reports the development of epoxy-based biocomposites via the valorization of coconut fiber, with tailored thermal and mechanical properties obtained by varying the reinforcement and curing system. An organosolv process was used to extract lignin from natural coconut fiber (NCF) using a 90% v/v aqueous acetic acid solution combined with 2% v/v HCl at 110 °C for 1 h, yielding organosolv coconut fiber lignin (OCFL) and modified coconut fiber (MCF). The polymeric matrix was composed of diglycidyl ether of bisphenol A containing 0 or 50 wt% OCFL, while NCF and MCF were used as reinforcements. The biocomposites were prepared with a matrix-to-reinforcement mass ratio of 80:20 and cured with either a protic or an aprotic ionic liquid, specifically 10 wt% [HMIM][HSO4] at 180 °C or 10 wt% [BMIM][PF6] at 220 °C for 1 h. The biocomposites were characterized by thermogravimetry, constant-pressure calorimetry, gel content, water absorption, chemical resistance, scanning electron microscopy and dynamic mechanical analysis. The results show that the thermal, thermos-oxidative, chemical, and mechanical properties of the biocomposites can be modulated by controlling the type of reinforcement, the lignin content in the matrix, and the curing ionic liquid. The valorization of coconut solid residues through a sustainable organosolv-based route thus enables the design of thermosetting materials with high glass transition temperatures, high gel content, and self-extinguishing behavior suitable for high-performance applications, with potential to partially replace petroleum-derived materials in selected sectors of the chemical industry.
The corrosion inhibition behavior of carbon steel (CS) in 1.0 M HCl in the presence of 4-(2-(4-oxo-3-phenyl-3,4-dihydroquinazolin-2-yl) vinyl) phenyl benzenesulfonate (4-OPB) and4-(2-(3-(4-hydroxyphenyl)-4-oxo-3,4-dihydroquinazolin-2-yl)vinyl)phenyl benzenesulfonate (4-HPB) was investigated through chemical evaluation via weight loss (WL) measurements, as well as electrochemical techniques, including AC impedance (EIS), and potentiodynamic polarization (PDP). The inhibition efficiency (IE) increased progressively with higher concentrations of the tested compounds and with temperature elevation, reaching a maximum of 93.2% and 90.1% at 21 × 10⁻3 M of 4-HPB and 4-OPB, respectively from WL tests at 25C. In the other hand, it reached 96.5%, 95.9% for 4-HPB and 4-OPB at 45oCand the same concentration, respectively. The findings indicated that these compounds adhere on the CS surface and create a protective film whose formation conforms to the Langmuir adsorption isotherm, consistent with chemisorption, as supported by the relatively high adsorption energy values (ΔG°ads < - 46 kJ mol⁻1), rise in % inhibition by raising the temperature and the lowering in activation energy (E*) in presence of inhibitors than in its absence. These chemical compounds function as mixed-type inhibitors, according to PDP studies. Surface characterization of the inhibited CS using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and Fourier transform infrared spectroscopy (FTIR) demonstrated significant improvement in surface morphology. The collective results from all employed techniques exhibited strong agreement, validating the inhibitory performance of the studied compounds.
In this work, PANI/CNT/CC composite is developed as a positive electrode for flexible zinc-ion battery (ZIB) with the high specific capacity. Assembled flexible batteries are subjected to electrochemical testing. A double grid structure constructed by CNT modification of polyaniline nanofiber network on carbon cloth and CNF modification of PAM gel further improved its flexibility and bending ability. The optimized battery exhibits a high specific capacity of 210 mA hg⁻¹ at a current density of 0.5 A g⁻¹, i.e., a marked improvement in rate performance and bending stability. Following 800 charge and discharge cycles at a current density of 2 A g⁻¹, the battery demonstrates an impressive capacity retention rate of approximately 90.6% along with a notable average coulombic efficiency of 98.7%, underscoring its remarkable strength and stability. The PANI/CNT/CC|CNF/PAM|Zn battery can power the device when it is bent or even folded. Such enhanced electrochemical performance of optimized ZIB is originated from synergistic coupling between the 3D cathode and CNF/PAM dual-network hydrogel electrolyte, which simultaneously facilitates electron transport, Zn2+ ion diffusion, and interfacial stability.
Density functional theory (DFT) is widely used for modeling molecular energetics, yet the accuracy of density functionals strongly depends on the chemical environment, making reliable functional selection across diverse applications. To facilitate the rational selection of functionals, we systematically assess the performance of 26 density functionals across six representative classes of molecular energetics, including reaction barriers, polar σ-bond dissociation, ionization energies, metal-ligand dissociation, catalytic barrier heights, and strongly correlated 3d transition-metal complexes. By jointly analyzing datasets spanning both main-group and transition-metal chemistry, this work provides a cross-domain assessment of functional performance across chemically distinct regimes. Our results indicate that functional transferability between these two domains tends to be constrained, with relatively few hybrid meta-NGAs and hybrid meta-GGAs (e.g., CF22D, PW6B95-D3(BJ)) demonstrating comparatively balanced accuracy across diverse datasets, while multi-reference cases remain challenging for all functionals considered. The dataset-specific analysis provides practical insights for functional selection: HSE06-D3(BJ), PBE-D3(BJ), and M06-2X-D3(0) functionals perform well for main-group reaction barriers, while CF22D, M06-D3(0), M06 and MN15 functionals are more reliable for polar bond dissociation. For transition-metal energetics, CF22D, PW6B95-D3(BJ), and HSE06-D3(BJ) functionals offer robust performance. Overall, this study delineates the strengths and limitations of modern density-functional approximations and offers data-driven guidance for functional selection in heterogeneous molecular problems.
Microbial melanins are exceptionally recalcitrant biopolymers that facilitate fungal virulence and biodeterioration. This review synthesizes physical, chemical, and biological degradation strategies for major microbial melanin categories, aligning technical mechanisms with their translational potential. While physical methods such as ultrasound-assisted (UAE) and microwave-assisted extraction (MAE) function as matrix-disrupting pretreatments rather than standalone degradation strategies, chemical approaches remain the analytical standard for structural fingerprinting via specific markers like pyrrole-2,3,5-tricarboxylic acid (PTCA), pyrrole-2,3-dicarboxylic acid (PDCA) and 4-amino-3-hydroxyphenylalanine (AHP). Conversely, biological approaches, primarily utilizing ligninolytic enzymes such as laccases and peroxidases that catalyze the oxidative breakdown of complex melanin structures, offer the most sustainable route for applied degradation. We critically evaluate emerging biotechnological solutions, including immobilized nanobiocatalysts like LiP@MFO-GO (LiP immobilized onto graphene oxide coated magnetic nanoparticles), engineered synergistic laccase-peroxidase complexes for in situ H2O2 recycling, and the use of glutathione peroxidase (GPX) from lysosome-related extracts, highlighting their stability and reusability under industrial conditions. Finally, we outline a strategic framework to overcome mediator toxicity and ensure the generation of biocompatible fragments, providing a roadmap for innovative applications in cosmetics, food preservation, and environmental remediation.
Monolithic zirconia has become increasingly popular in clinical dentistry as an indirect restorative material fabricated using computer-aided design/computer-aided manufacturing (CAD/CAM) technology. It is widely used due to its favorable combination of mechanical strength, aesthetic potential, and biocompatibility. Its monolithic design reduces the risk of veneer chipping, thereby improving restoration longevity. To narratively review the mechanical and adhesive properties of monolithic zirconia and discuss their clinical implications. This narrative review was based on a comprehensive, non-systematic literature search conducted using PubMed/MEDLINE, Scopus, and Web of Science. English-language publications addressing monolithic zirconia, mechanical behavior, surface treatments, adhesive strategies, and clinical performance were considered. Additional studies were identified through manual screening of reference lists. Study selection was guided by relevance to the review topic rather than predefined inclusion or exclusion criteria. Monolithic zirconia demonstrates high flexural strength and fracture toughness, supporting its use in posterior load-bearing restorations. However, direct exposure to the oral environment may promote low-temperature degradation (LTD), potentially affecting long-term mechanical stability. Despite improvements in translucency, aesthetic performance remains a consideration. Adhesive durability depends largely on appropriate surface conditioning and the use of functional primers, particularly those containing 10-methacryloyloxydecyl dihydrogen phosphate (MDP), which enhance chemical bonding to zirconia. Monolithic zirconia offers a reliable balance between strength and clinical durability. Nevertheless, its long-term performance is influenced by environmental exposure and adhesive protocols. Further research is needed to optimize the resin-zirconia interface while maintaining both mechanical reliability and aesthetic outcomes.
Living tissues strengthen under repeated mechanical loading, yet replicating such adaptive growth in synthetic materials remains a formidable challenge. Here, we report a protein-based hydrogel that undergoes mechanochemically induced self-growth, autonomously reinforcing its baseline mechanical properties under applied stress. This strategy harnesses the copper-storage protein Csp1, whose force-regulated unfolding releases Cu(I) that catalyzes in situ azide-alkyne cycloaddition, generating secondary crosslinks under mechanical load. Upon unloading, Csp1 refolds and re-sequesters Cu(I), halting catalysis and restoring growth capacity. This mechano-catalytic feedback loop enables stress- and time-dependent self-reinforcement within a closed system, without external monomer supply. The hydrogel exhibits programmable mechanical memory via leveraging Cu(I) homeostasis in cyclic growth-pause-growth transitions. By coupling force-dependent protein conformational dynamics with catalytic activity, this strategy establishes a generalizable mechanochemical framework for designing self-adapting biomaterials whose structure and function evolve under mechanical stimulation.
This study examines the gas-phase elimination of ethylene from a series of quinoline and azulene derivatives namely, 2-ethoxyquinoline (2-EQ), 8-ethoxyquinoline (8-EQ), 2-ethoxyazulene (2-EA), and 8-ethoxyazulene (8-EA) using computational methods over the temperature range of 298-1200 K. Density functional theory (DFT) calculations were performed with the M06-2X and ωB97XD functionals and complemented by the composite G3MP2 method. Thermochemical and electronic properties, including enthalpies of formation, frontier molecular orbitals, chemical hardness, and molecular electrostatic potential, were analyzed. The reliability of the computational approach was evaluated through comparisons of calculated enthalpies of formation with available experimental and theoretical literature data, as well as by assessing correlations between G3MP2 and DFT results. Kinetic parameters for all proposed reaction pathways were determined at the G3MP2 level. The results reveal that formation of the keto tautomer of 1H-cyclohepta [b]pyrrol-8-one (P7) is the most kinetically favorable pathway, proceeding via a seven-membered-ring transition state (TS7) with an activation barrier of 35.11 kcal/mol.
Modern biochemistry is producing vast amounts of chemical knowledge. Ontologies, such as the Chemical Entities of Biological Interest (ChEBI) ontology, can help organising this knowledge. With manual classification alone however, ontologies cannot keep up with the growth of their domain. In this work, we propose a novel taxonomy of 67 classes related to peptides, a large branch in ChEBI with nearly 15,000 compounds. The existing natural language definitions in ChEBI have been expanded and specified more precisely. These natural language definitions are accompanied by a logical axiomatisation in monadic second-order logic (MSOL). To use the axiomatisation for automated classification, a methodology has been developed that translates monadic second-order definitions first into partial first-order definitions and finally into an algorithmic classification. This connects three aspects important to ontological definitions: They reflect the opinions of experts, they are unambiguous, and they can be checked automatically. In our evaluation, we compare the results of our classification to the current taxonomy of ChEBI . This reveals potential inconsistencies in ChEBI as well as areas that might benefit from automated extensions. We also evaluate our natural-language definitions in an expert survey.Scientific contribution: This work provides precise natural-language definitions of 14 current ChEBI classes as well as 53 new peptide-related classes. These definitions are formalised in MSOL and come with an efficient implementation that allows for large-scale molecule classification, including a full classification of ChEBI and PubChem.
Photolabile protecting groups (PPGs) enable spatiotemporal control of chemical and biological processes, yet multistimuli-regulated systems remain rare. Here we report a triple-stimuli platform integrating light, base, and acid to control PPG release. Photoirradiation of diarylethenes (DAEs) under basic conditions generates stable 9,10-dihydrophenanthrene (9,10-DHP) intermediates that activate hemiaminal ethers and undergo acid-promoted aromatization to release the alcohol group. Distinct fluorescence changes allow real-time monitoring in both organic and aqueous media.
Mitochondria are well established as key supporters of synaptic plasticity, yet the nanoscale spatial distribution of specific mitochondrial membrane proteins during this process remains poorly understood. Using 3D MINFLUX nanoscopy, we investigated their polarized distribution within synapses of cortical neurons undergoing chemical long-term potentiation (cLTP). Upon cLTP induction in DIV17 neurons, we observed an increased mitochondrial occupancy in stimulated synapses. Respiratory complexes of the inner mitochondrial membrane (IMM)-such as COX-IV and SDHA-showed a polarized accumulation near presynaptic sites, as validated by cluster analysis and 3D mapping. By contrast, outer mitochondrial membrane (OMM) proteins, including TOMM20 and VDAC, exhibited no significant polarized distribution. Together, these results demonstrate that cLTP selectively remodels the inner mitochondrial membrane to address localized energy requirements, highlighting the power of 3D MINFLUX for resolving protein organization with subcellular precision.
Geminal difunctionalization of carbonyl-derived building blocks represents a versatile strategy for the rapid generation of sp3-rich molecular architectures. In this context, diazo compounds provide a powerful platform for installing two distinct functional groups, yet the reaction space for carbonyl-derived donor-donor diazo systems remains underdeveloped. Here, we report a metal-free migratory insertion of diazo compounds into C─S bonds of sulfonyl cyanides, enabling the simultaneous installation of sulfone and nitrile functionalities at a single carbon center. Key to this transformation is the in situ generation of highly reactive diazo intermediates via photochemical decomposition of bench-stable oxadiazolines derived from ketones. This substantially expands the accessible coupling partner space, previously limited to aldehydes or boronic acids. The reaction exhibits broad functional group, water, and air tolerance, delivers high yields, and provides excellent diastereoselectivity in constrained cyclic systems. Compatibility with both batch and continuous-flow processing, as well as its application to a realistic medicinal chemistry combinatorial library synthesis, highlights the practical utility of the method.
The sustainable production of silver nanoparticles (AgNPs) from renewable biowaste would reduce environmental burden and expand green nanotechnology applications. This study reports a hydrothermal extraction route that avoids external chemical reductants, thereby enabling duck-feather keratin to function intrinsically as both a reducing and capping agent in the synthesis of stable, bioactive AgNPs. Extraction was verified using the Lowry assay and SDS-PAGE, confirming preservation of protein content needed for metal coordination. One-factor-at-a-time optimization identified pH 11, 70 °C, 30 mL extract per 1 mM Ag⁺ reaction, and a 24 h duration as optimal conditions, producing uniform spherical nanoparticles having an average (11 nm) with excellent dispersion and long-term optical stability. Characterization by UV-Vis, FTIR, XRD, and SEM-EDX confirmed Ag⁺ reduction, keratin capping, and crystalline face-centered cubic Ag formation. TGA-DTA showed improved thermal stability, while BET surface area increased from 1.55 to 6.32 m2·g⁻1 after nanoparticle incorporation, indicating enhanced mesoporosity. The synthesized duck-feather keratin silver nanoparticles (DFKSN) demonstrated strong antioxidant activity and potent antibacterial performance, with DDT, MIC, and MBC assays confirming both bacteriostatic and bactericidal effects against Gram-positive and Gram-negative bacteria. The nanoparticles also promoted cytocompatibility in human skin fibroblasts cell (HSF1184) at a dose of 3.0 mg.mL-1. These findings highlight hydrothermally processed keratin as a scalable, waste-valorizing route for sustainable and eco-friendly nanomaterial production.