Plexcitonic assemblies are hybrid materials composed of a plasmonic nanoparticle and molecular or semiconducting emitters whose electronic transitions are strongly coupled to the plasmonic mode. This coupling hybridizes the system modes into upper and lower polariton branches. The interaction strength depends on the number of emitters and on their orientation and spatial arrangement relative to the metallic surface. These structural factors have profound consequences for the ensuing photoexcited dynamics. Despite the extensive spectroscopic work on plexcitonic systems, direct understanding of the molecular geometry at the metal interface remains limited. We present a comprehensive structural characterization of a model plexciton formed by the cyanine dye 5,5',6,6'-tetrachloro-1,1'-diethyl-3,3'-di(4-sulfobutyl)-benzimidazolocarbocyanine (TDBC) and silver nanodisks using NMR, THz-Raman spectroscopy, and density functional theory calculations. By comparing the signals from the monomeric and aggregated forms of TDBC with those of the plexciton, we identify shared spectral fingerprints that reveal how molecular packing is modified when the aggregate adsorbs on the silver surface. We observe Raman modes specific to plexciton systems and identify NOESY cross-peaks in the aliphatic region that, along with several Raman modes, are sensitive indicators of aggregation geometry and adsorption. We find that TDBC monomers adopt an asymmetric conformation in which both sulfobutyl chains lie on the same side of the chromophore, while J-aggregates adopt a symmetric up-down alternation of the chains from molecule to molecule, which becomes distorted and loses long range periodicity when adsorbed on Ag nanodisks. This work constrains the molecular geometry and interfacial arrangement of a prototypical TDBC-silver plexciton, providing a structural benchmark for understanding geometry-dependent photophysics in exciton-plasmon systems.

Although continuous symmetry theory has attracted increasing attention in modern chemistry, local symmetry remains under-investigated. As a consequence, the relationship between symmetry and chemical behavior is often obscured, limiting the practical use of fuzzy symmetry measures. In this study, we introduce a novel framework for evaluating local symmetry based on electron density localization and present continuous symmetry representations for several representative molecules. Our approach not only quantitatively captures global symmetry but also reveals distinctive features of symmetry in a local chemical environment. The related concept, local chirality or chirotopicity, is also discussed. Overall, the proposed local symmetry and chirality measures provide valuable insights into molecular structure and structure-property relationships.

Single-particle techniques have the potential to measure the heterogeneous dynamics at the nanoscale within reaction mixtures. However, new tools are needed to gain insight into the molecular structure of evolving chemical systems at the single-particle level. Here, a single-particle method for measuring the density and mass of freely diffusing polymer nanoparticles is introduced and applied to the ring-opening metathesis polymerization of norbornene. Using 3D single-molecule active real-time tracking, growing polymer nanoparticles are tracked in situ, enabling simultaneous real-time measurement of both particle size and particle density. Particle density is extracted from the descent velocity of growing nanoparticles, giving insight into particle composition at the single-particle level. Using this technique, it is found that polynorbornene nanoparticles have a density of 850 ± 30 kg/m3, validated through control measurements on polystyrene beads. Density and size analysis indicate each nanoparticle contains ∼3.5 × 109 densely packed monomers, rather than loosely packed polymer chains. Simulations show that the accuracy of this method depends on particle size, the distance traveled before contact with the coverslip, solvent properties, and the number of trajectories. Overall, this paper presents a technique that enables in situ characterization of the density and mass of individual growing polymer nanoparticles.

T cells are central to adaptive immunity, and continuously sense, generate, and respond to mechanical forces. Advances in mechanoimmunology show that T-cell behavior is tightly shaped by the physical properties of their environment, including stiffness, viscoelasticity, ligand arrangement, and tissue topography. T-cell activation depends not only on biochemical signals but also on forces transmitted through the T-cell receptor, coreceptors, and mechanosensitive ion channels, which converge on the cytoskeleton to regulate signaling and effector function. When these mechanical interactions are disrupted, as in cancer, autoimmune diseases, or aging, T-cell function is impaired. Despite recent progress, T-cell mechanobiology remains partially understood, limited by challenges in measuring forces at relevant spatial and temporal scales. Incorporating biophysical principles into the design of immunotherapies may enhance treatment efficacy, specificity, and safety. This review summarizes emerging concepts in T-cell mechanobiology and outlines key challenges and future directions toward integrating mechanical and biochemical regulation of adaptive immunity.

Seven new crystal structures of 3,6-bis(pyridin-2-yl)-1,2,4,5-tetrazine (2-bptz) and 3,6-bis(pyridin-4-yl)-1,2,4,5-tetrazine (4-bptz) were determined with inorganic halogen donors (I2 or I3-), organic halogen donors [1,4-diiodotetrafluroobenzene (p-F4DIB) or 1,3,5-trifluoro-2,4,6-triiodobenzene (1,3,5-TFTIB)], and the hydrogen-bond donor hydroquinone to investigate how pyridyl orientation and donor type influence supramolecular assembly. Structures formed with molecular iodine, namely, 2,2'-(1,2,4,5-tetrazine-3,6-diyl)dipyridinium bis(triiodide)-3,6-bis(pyridin-2-yl)-1,2,4,5-tetrazine-diiodine (1/1/1), C12H10N62+·2I3-·C12H8N6·I2 (1), and 4-[6-(pyridin-4-yl)-1,2,4,5-tetrazin-3-yl]pyridinium pentaiodide, C12H9N6+·I5- (2), are dominated by N-H...N hydrogen bonding, with pyridine protonation yielding distinct packing arrangements: 2-bptz forms stacked triads along the a axis, whereas 4-bptz assembles into chains of [H(4-bptz)]+ cations alternating with pentaiodide layers. Replacement of iodine with organoiodines in 3,6-bis(pyridin-2-yl)-1,2,4,5-tetrazine-1,4-diiodotetrafluorobenzene (1/1), C6F4I2·C12H8N6 (3), 3,6-bis(pyridin-4-yl)-1,2,4,5-tetrazine-1,4-diiodotetrafluorobenzene (1/1), C6F4I2·C12H8N6 (4), and 3,6-bis(pyridin-2-yl)-1,2,4,5-tetrazine-1,3,5-trifluoro-2,4,6-triiodobenzene (1/2), C6H4N3·C6F3I3 (5), shifts the primary interactions to C-I...N halogen bonding, producing one-dimensional staggered chains in 2-bptz and linear motifs in 4-bptz, with bifurcated C-I...N interactions in 5 involving both pyridine and tetrazine N atoms. Halogen-halogen and halogen-fluorine interactions further modulate packing and stacking orientations. Reactions with hydroquinone in 3,6-bis(pyridin-2-yl)-1,2,4,5-tetrazine-hydroquinine (2/1), 2C12H8N6·C6H6O2 (6), and 3,6-bis(pyridin-4-yl)-1,2,4,5-tetrazine-hydroquinine (1/1), C12H8N6·C6H6O2 (7), reveal the role of hydrogen bonding in long-range organization: 2-bptz forms discrete triads, whereas 4-bptz generates extended chains propagating through pyridine-phenol interactions. Pyridine-to-tetrazine plane-to-plane angles vary across structures, reflecting the influence of substitution pattern and donor type on molecular geometry. These results demonstrate that subtle changes in pyridyl orientation and the nature of halogen- or hydrogen-bond donors can direct the formation of distinct supramolecular architectures, providing a foundation for the rational design of tetrazine-based crystalline materials with tunable packing and noncovalent interactions.

With the increasing demand for sustainable agriculture and efficient nitrogen fertilizer utilization, fertilizer synergists, including urease inhibitors, nitrification inhibitors, and biostimulants, have received a growing amount of attention. However, their mechanisms of action are often examined in isolation, and a unified structure-activity relationship (SAR) framework linking molecular structure to efficacy is still lacking. This review provides a mechanistic overview of fertilizer synergists from a molecular perspective, integrating SARs across these three classes. For urease and nitrification inhibitors, molecular features governing enzyme recognition and binding predominantly determine the inhibitory efficacy. By contrast, biostimulants exhibit more complex and multilayered SARs, in which molecular structure not only enhances nutrient utilization but also modulates plant signaling pathways, thereby promoting stress tolerance and plant growth. Finally, this review provides structure-guided insights and design strategies to support the development of novel fertilizer synergists with improved efficiency, multifunctionality, and environmental compatibility.

From hapten design to in situ detection: development of highly specific visual immunochromatographic sensor strips for sulfaguanidine antibiotics in animal sourced foods.

One-step microwave-assisted synthesis of nitrogen-doped carbon quantum dots for highly sensitive and selective fluorescence detection of mercury (II) ion in food.

Effective mucolytic therapy can greatly improve the efficacy of cytoreductive surgery + hyperthermic intraperitoneal chemotherapy, alleviate symptoms and improve prognosis for pseudomyxoma peritonei (PMP) patients. The main components of PMP mucus are highly O-glycosylated proteins called mucins. Represented by mucin2 (MUC2), mucins are the source of mucus viscoelasticity. This review investigated detailed processes of mucin O-glycosylation and mucolytic therapies in PMP. We introduced molecular pathological mechanism of PMP, types of mucus and mucins in PMP, molecular structure and biological functions of mucins. We focus on the synthesis process and physiological functions of MUC2 O-glycosylation. Furthermore, we summarize the potential therapeutic approaches to inhibiting mucin secretion and mucolysis. Detailed process of mucin O-glycosylation in endoplasmic reticulum and Golgi apparatus was discussed. We discussed promising approaches to targeting the substrates and enzymes in O-glycosylation, including uridine diphosphate and GalNAc analogs/derivatives, ppGalNAc-T/GALNT inhibitors, disulfide bond reducing agents or PDI inhibitors, O-glycosidases, and glucoproteinases. We provide a reference for the development of PMP mucolytic therapy, and some potential therapeutic targets aiming at mucin O-glycosylation.

Isosakuranetin is a natural flavonoid containing a 4'-O-methyl group on the molecular structure and has a broad range of pharmacological activities. In this study, a sensitive and robust UPLC-ESI-MS/MS method was developed and fully validated for quantitative determination of isosakuranetin in rat plasma, enabling a comprehensive evaluation of the pharmacokinetics and oral bioavailability of isosakuranetin. Isoscoparin was the internal standard (IS). The plasma samples were prepared by protein precipitation with acetonitrile. Chromatographic separation was conducted with a BEH C18 column and a gradient mobile phase consisting of acetonitrile and 0.1% formic acid aqueous solution. The detection was accomplished in negative electrospray ionization (ESI) by multiple reaction monitoring (MRM) mode. The assay had excellent linearity (r > 0.995) in a linear concentration range of 0.5-800 ng/mL. Precision (intra- day and inter-day) was less than 13%, and extraction recovery was above 89%. Accuracy was between 91% and 113%, and the matrix effects were 93%-104%. Overall, this method was rapid, specific, reproducible, and sufficiently sensitive for invivo pharmacokinetic studies in rats. After oral administration, the absolute bioavailability of isosakuranetin was calculated to be 64.6%.

Ginsenoside Rb1 attenuates hyperoxia-induced lung injury in neonatal rats by inhibiting ferroptosis via the system Xc- pathway.

Polycyclic aromatic hydrocarbons (PAHs) are widespread air pollutants in the Earth's atmosphere. Understanding their structure is relevant for the study of their interactions with other atmospheric molecules and their participation in aerosol formation. Here we present the investigation of the structures of the most abundant nitrated PAHs in the atmosphere, 1-nitronaphthalene (1NN) and 2-nitronaphthalene (2NN), using high-resolution chirped pulse Fourier transform microwave spectroscopy and quantum-chemical calculations. The rotational constants, centrifugal distortion constants and 14N nuclear quadrupole coupling constants for both 1NN and 2NN were determined. The observation of the heavy atom isotopologues in natural abundance led to the determination of experimental structures using substitution, effective, and mass-weighted methods. Moreover, semi-experimental equilibrium structures for 1NN and 2NN were determined by using a reduced-cost protocol based on the Pisa Composite Schemes, which combines the experimental heavy-atom isotopologue data with hydrogen atom positions and vibrational corrections obtained from affordable quantum chemical calculations. The resulting semi-experimental equilibrium structures achieve spectroscopic accuracy, demonstrating the robustness and transferability of this strategy for nitroaromatic systems. Comparison of the bond lengths and angles of 1NN and 2NN with those of related substituted naphthalenes enabled identification of common structural trends.

Enhancing PgUGT activity and thermostability via mutation site screening aided by molecular docking structure and computer-aided design for efficient industrial synthesis of rebaudioside D.

Tuberculosis (TB) is a major global health issue worsened by drug-resistant isolates. This study presents a detailed in silico investigation of isoscopoletin by combining quantum-chemical calculations, pharmacokinetic profiling, molecular docking, and molecular dynamics simulations against the Mycobacterium tuberculosis target protein thymidylate kinase. Structural stability was established by geometry optimization using density functional theory (DFT) at the APFD/6-311+G(2d,p) level of theory. The optimized molecular geometry was used to obtain HOMO-LUMO energies, chemical reactivity descriptors and molecular electrostatic potential (MEP). Frontier molecular orbital analysis showed a small HOMO-LUMO energy gap of 4.3 eV, indicating high reactivity, while molecular electrostatic potential (MEP) mapping highlighted reactive nucleophilic and electrophilic regions. Topology analyses, such as ELF, LOL, RDG, NCI, frontier orbital analysis, and molecular electrostatic potential mapping, were all insightful for charge distribution and non-covalent interactions. Pharmacokinetic and ADMET profiling demonstrated favorable drug-likeness, with a TPSA of 59.67 Å2 and a bioavailability score of 0.55. Molecular docking suggested strong binding affinity, which was further validated by 200 ns molecular dynamics simulations. The protein-ligand complex exhibited stable RMSD values ranging from 1.0 to 2.6 Å (average ≈ 1.8 Å) compared to the free protein (1.8-3.0 Å; average ≈ 2.4 Å), indicating enhanced stability upon ligand binding. RMSF analysis showed minimal residue fluctuations (0.05-0.20 nm), while the radius of gyration remained stable between 1.60 and 1.72 nm. Principal component analysis revealed that the first three components (PC1: 26.16%, PC2: 14.45%, PC3: 9.14%) accounted for 49.8% of the total motion, indicating coordinated and stable dynamics. These computational findings demonstrate that isoscopoletin exhibits favorable electronic properties, stable protein-ligand interactions, and good pharmacokinetic characteristics, supporting its application as an anti-tubercular drug.

Structural studies of N, O donor (imino)/(amino)pyridine mononuclear zinc(II) complexes as catalysts in the ring-opening polymerization reactions of rac-lactide

A general tyrosinase-responsive prodrug strategy: design and synthesis of melanoma-selective anticancer agents.

Eggs are natural and multifunctional bioresources, and their components are widely applied in the food, biomedical, functional, and environmental fields. Most studies have focused on the chemical properties or functional characteristics of individual components, and a systematic understanding that connects molecular structure, material performance, and cross-disciplinary applications is lacking. This review comprehensively synthesized existing studies, covering inorganic constituents (e.g., eggshell minerals), natural fibers (e.g., eggshell membrane), and protein and lipid structural features, determining their roles in functional regulation, interfacial activity, network formation, and material properties. Advancements in egg-based composite systems, including protein-polysaccharide networks, egg yolk lipid-based nanocarriers, eggshell-eggshell membrane composites, and protein-keratin crosslinked systems, are highlighted. The effects of the conditions of preparation, composite strategies, and interfacial modulation on the microstructure, rheology, film-forming ability, and stability were critically discussed. Future perspectives were proposed, emphasizing multicomponent synergistic design, cross-phase interface engineering, and the development of egg-based smart materials. This framework provides a systematic reference for using eggs in high-performance food systems, biomedical applications, and functional composite materials.

Effect of polycarboxylate superplasticizer on the hydration of cubic C3A: Interaction with sulfate ions and correlation to molecular structure

Diffusion mechanism analysis of rejuvenator-aged asphalt system from multi-scale perspective

Quantum chemical, spectroscopic, molecular docking, molecular dynamics analyses and ADMET properties: Nifedipine.