Search Results (9,060)

Waste cooking oil (WCO) was investigated as a waste-derived reactive precursor for a cured organic binder in highly mineral-filled composites containing turmeric. Ten formulations selected from a broader experimental screening were prepared from WCO, sulfuric acid, quartz sand, and turmeric added at 1–7% relative to the dry mass of quartz sand. Formulation-specific thermal curing was conducted at 190–210 °C for 12–20 h. Because the binder content, acid-to-binder ratio, turmeric content, curing temperature, and curing time varied simultaneously, the study was designed as an exploratory multifactorial screening rather than as a controlled assessment of individual processing variables. FTIR, ¹H NMR analysis of acetone-soluble constituents, TGA, and SEM-EDS were combined with mechanical screening, water-absorption, contact-angle, and microbiological measurements. Bending and splitting tensile strengths ranged from 1.15 to 2.42 MPa and from 0.30 to 0.52 MPa, respectively. Water absorption ranged from approximately 4.8% to 9.0%, while water contact angles exceeded 90° for all investigated formulations. Selected formulations reduced the surviving fraction by more than 90% for Staphylococcus epidermidis and by approximately 70% for Pseudomonas aeruginosa under the applied suspension-assay conditions. The estimated C₅₀ values of 60.6–83.3 mg mL⁻¹ indicated measurable concentration-dependent responses at relatively high nominal composite concentrations. The available results support curing-associated transformation and consolidation of the WCO-derived binder phase but do not quantify crosslink density or retained organic content. Because no matched turmeric-free composite or surface/eluate pH measurements were available, the biological effects are attributed to the complete composite formulations rather than specifically to turmeric or intact curcumin. The results provide an exploratory basis for the further development of waste-derived, non-load-bearing polymer–mineral composites with functional surface and biological properties. Full article

Retinal degeneration is characterized by progressive photoreceptor loss driven by oxidative stress and chronic inflammation, yet effective mutation-independent therapeutic strategies remain limited. Lycium barbarum polysaccharides (LBPs) possess antioxidant and anti-inflammatory activities; however, the structural features responsible for their retinal protective effects remain poorly defined. In this study, crude LBP was fractionated by DEAE-cellulose ion-exchange chromatography, and the most bioactive fraction, LBPF2, was identified using H₂O₂-injured 661W cone photoreceptor-like cells. LBPF2 was subsequently characterized by high-performance anion-exchange chromatography, SEC-MALLS-RI, GC–MS methylation analysis, and one- and two-dimensional NMR spectroscopy, and its protective effects were evaluated in H₂O₂-treated 661W cells and rd10 mice. LBPF2 was identified as a homogeneous glucose-rich polysaccharide with an average molecular weight of approximately 41 kDa and a backbone mainly composed of →4)-α-D-Glcp-(1→ and →4,6)-α-D-Glcp-(1→ residues. LBPF2 reduced oxidative stress, inflammation, and apoptosis in H₂O₂-treated 661W cells, preserved retinal morphology, improved electroretinographic responses and partial retention of rhodopsin immunoreactivity relative to untreated rd10 mice, and restored redox homeostasis in rd10 mice. Pharmacological inhibition of Nrf2 using ML385 attenuated these protective effects, supporting the involvement of Nrf2/HO-1 signaling. Collectively, these findings identify LBPF2 as a structurally characterized neuroprotective polysaccharide that mitigates retinal degeneration through coordinated regulation of oxidative stress and inflammation and highlight its therapeutic potential for retinal degenerative diseases. Full article

To investigate the electron-donating substitution effect on spin crossover (SCO) and electrochemical behaviors for homoleptic trivalent metal complexes with 2,2′-azobisphenolate (azp) ligands, the known 2,2′-azobisphenol with 5,5′-dimethyoxy substituents (H₂L^OMe) was synthesized and characterized by NMR spectroscopy and single-crystal X-ray diffraction (SCXRD). The homoleptic Fe^III and Al^III complexes 1-OMe and 2-OMe were prepared along with the homoleptic Fe^III complex with 5,5′-dimethyl-substituted azp ligands 1-Me. The temperature dependence of magnetic susceptibility and SCXRD revealed that 1-OMe exhibits incomplete gradual SCO with the rotational motion of the ligands. Cyclic voltammograms and their simulations revealed that both the Fe^III complex 1-OMe and the Al^III complex 2-OMe exhibit reversible one-electron oxidation waves, indicating that the introduction of the methoxy group enhances the stability of the oxidized species of the complexes. DFT calculations revealed that the oxidation waves for both the Fe^III and Al^III complexes are ligand-centered, while the reduction wave for the Fe^III complexes 1-OMe and 1-Me is metal-centered. In addition, the stability of the oxidized complex species arises from the resonance effect of the methoxy group. Full article

As interface control technology has become crucial for preventing pattern collapse caused by the miniaturization of display and semiconductor devices, surfactants are essential in core manufacturing processes, including electroluminescence. Therefore, high-performance surfactants capable of achieving efficient liquid penetration and wettability control in high-aspect-ratio architectures are urgently needed. To address this need, this study suggested two glyceryl ether derivatives, 3-(hexyloxy)propane-1,2-diol (Hex-PD) and 3-((2-ethylhexyl)oxy)propane-1,2-diol (Oct-PD), alongside a monoalcohol ether derivative, 1-methoxy-3-(pentyloxy)propan-2-ol (Pen-PMO), and systematically investigated the effects of structural variation on optical transmittance, molecular polarity, and interfacial behavior. The target compounds were successfully obtained, as confirmed by ¹H NMR and FT-IR analyses. At 0.01 wt%, all three compounds showed relatively high transmittance at 248 nm. Surface tension measurements at 0.1 wt% revealed values of 38, 35, and 31 mN/m for Hex-PD, Oct-PD, and Pen-PMO, respectively, and their corresponding water contact angles were 45.5°, 44.3°, and 47.8°. Overall, Pen-PMO exhibited favorable transmittance and wettability, as well as the lowest surface tension, indicating the highest interfacial activity among the three compounds. These results demonstrate that optical properties, molecular polarity, and interfacial properties can be controlled by tuning hydrophobic tail topology and hydroxy functionality across glyceryl and monoalcohol ether architectures. Full article

Introduction: PKMYT1 is a WEE-family G2/M cell cycle checkpoint kinase commonly overexpressed in a broad spectrum of human malignancies. WEE1 exclusively phosphorylates CDK1 at Tyr15, whereas PKMYT1 targets both Thr14 and Tyr15. Unlike WEE1 inhibition, PKMYT1 suppression triggers synthetic lethality with CCNE1. Nearly all disclosed PKMYT1 inhibitors so far fall into structural analogs originating from RP-6306, making the discovery of PKMYT1 inhibitors with chemotypes distinct from RP-6306 crucial. Methods: The compounds were structurally optimized using CADD, synthesized, and characterized by ¹H NMR, ¹³C NMR, HRMS, and HPLC. They were then assessed for kinase binding affinity via the LanthaScreen^TM Eu kinase binding assay, for cellular activity using the CCK-8 assay, and for cell-cycle distribution by flow cytometry, along with investigations into related mechanisms. Results: This study yielded 24 compounds of 2-aminopyrimidine through substituent derivatization of the pyrimidine scaffold. Among these derivatives, MS13 exhibited potent kinase binding affinity against PKMYT1 (IC₅₀ = 0.86 nM) and demonstrated strong anti-proliferative activity against CCNE1 high-amplification OVCAR3 cells and HCC1569 cells (IC_50-OVCAR3 = 1.52 μM, IC_50-HCC1569 = 0.66 μM). Additionally, it showed some selectivity towards A549 and HEK293T cells, with SI values of 4.31 (A549/OVCAR3), 9.92 (A549/HCC1569), 2.04 (HEK293T/OVCAR3), and 4.70 (HEK293T/HCC1569). Compound MS13 dose-dependently suppressed clonogenicity and triggered S-phase cell cycle blockade. Pharmacokinetic studies showed moderate hepatic microsomal stability (t_1/2 = 32.2 min). Molecular dynamics simulations indicated a favorable binding mode between compound MS13 and PKMYT1 (docking score: −9.322 kcal/mol). Conclusions: MS13 is a promising highly potent tool compound that provides a clear direction for the future optimization of PKMYT1 inhibitors. Full article

Carbohydrates are among the most highly oxygenated biomolecules in nature, possessing dense arrays of hydroxyl, ether, carbonyl, carboxylate, phosphate, and sulfate functionalities that govern hydration, hydrogen bonding, molecular recognition, and supramolecular organization. Their stereochemically organized oxygen-donor groups provide numerous appropriately oriented diol motifs capable of selective and reversible coordination with boric acid and borate ions. This review examines the structural and physicochemical principles underlying carbohydrate–borate interactions, with particular emphasis on oxygen-rich biological interfaces. Pentoses, hexoses, oligosaccharides, polysaccharides, glycolipids, and membrane-associated glycoconjugates are considered to illustrate how hydroxyl-group orientation, molecular conformation, pH, hydration, and local environment determine borate recognition, complex stability, and dynamic assembly. Evidence from NMR and other spectroscopic methods, crystallography, mass spectrometry, calorimetry, and molecular simulations demonstrates that borate coordination follows common stereochemical and thermodynamic principles despite the remarkable structural diversity of carbohydrates. Biological examples include borate-mediated crosslinking in plant cell walls and interactions involving microbial carbohydrates, marine polysaccharides and glycoconjugates, photosynthetic membrane lipids, and cyanobacterial heterocyst glycolipids. Particular attention is given to distinguishing experimentally established borate complexes from membrane-associated interactions that remain proposed and require further characterization. Reversible borate crosslinking of oxygen-rich carbohydrate networks also provides the chemical basis for emerging applications in responsive hydrogels, biosensors, supramolecular assemblies, drug-delivery systems, and functional biomaterials. Collectively, the available evidence indicates that the spatial organization of oxygen donor atoms within carbohydrates provides the molecular basis for selective borate recognition, whereas boron can convert this functionality into reversible higher-order organization. This oxygen-centered perspective integrates coordination chemistry, glycobiology, membrane biology, and materials science into a unified framework for understanding carbohydrate–borate interactions in natural and engineered systems. Full article

The accumulation of plastic waste has become a significant environmental challenge, stimulating the development of efficient recycling technologies capable of converting polymers into valuable products. In this study, polypropylene wastes were thermocatalytically converted into liquid hydrocarbons using three naturally occurring types of clay as catalysts, namely, kaolin, illite, and bentonite. The obtained liquid products were investigated using one- and two-dimensional NMR spectroscopy, including 1H, 13C, and COSY techniques. Quantitative evaluation of hydrocarbon group composition was performed using established NMR correlations to determine the content of paraffins, olefins and aromatic compounds as well as fuel-related parameters. The results demonstrated that paraffins were the predominant constituents in all pyrolysis oils, accounting for more than 70 vol.%, while olefins and aromatics were present in smaller amounts. Although all catalysts promoted the formation of liquid mixtures of hydrocarbon, noticeable differences in product composition were observed. Oil obtained over illite exhibited increased aromaticity and lower olefin content, whereas kaolin produced a product characterized by the highest isoparaffin index and estimated research octane number. The findings indicate that variations in catalysts influence the characteristics of polypropylene-derived oils and may be used to tailor products’ properties for their utilization as fuel additives or petrochemical feedstocks. Full article

In this study, we developed two complementary synthetic routes to novel piperidine- and azetidine-containing 2,3-disubstituted propanoic acid derivatives as heterocyclic amino acid building blocks. The strategy employs ketone- and carboxylic acid-derived Meldrum’s acid intermediates, which are converted into common α,β-unsaturated methyl esters through methanolysis; they are subsequently diversified via DBU-promoted aza-Michael addition with saturated cyclic amines and aromatic NH-heterocycles. The ketone-derived approach provided piperidine-containing derivatives in 35–89% yield and the corresponding azetidine analogues in 61–92% yield, whereas the complementary acid-derived route afforded regioisomeric products in 59–85% and 61–89% yield, respectively. Both synthetic sequences tolerated a broad range of nitrogen nucleophiles, and no alternative regioisomeric aza-Michael products were detected for heterocycles containing multiple nitrogen atoms. The structures of the synthesized compounds were established via ¹H, ¹³C, ¹⁵N, and ¹⁹F NMR spectroscopy together with HRMS, including detailed multidimensional NMR analysis of representative products. The developed methodology provides efficient access to structurally diverse heterocyclic propanoic acid derivatives and expands the repertoire of amino acid building blocks available for peptide chemistry, medicinal chemistry, and DNA-encoded library synthesis. Full article

Gonadotropin-Releasing Hormone receptors (GnRHRs) are overexpressed in several hormone-dependent malignancies, making them attractive molecular targets for selective anticancer drug delivery. Peptide–drug conjugates (PDCs) are a promising therapy for cancer and autoimmune diseases with high specificity and reduced toxicity. In this study, the three-dimensional structures of two previously synthesized mitoxantrone–GnRH conjugates, con3 and con7, were elucidated using high-resolution NMR spectroscopy in combination with molecular dynamics (MD) simulations. Complete ¹H and ¹³C resonance assignments were achieved in DMSO-d₆ through two-dimensional NMR experiments. NOESY-derived distance restraints were subsequently used to refine the conformational ensembles obtained from MD simulations performed in water and DMSO. Both conjugates exhibited compact bent conformations with a U-shaped peptide backbone. The mitoxantrone moiety is positioned close to the peptide backbone in water simulations and NMR-refined structures, while it is positioned farther away in DMSO, without affecting the orientation of key residues involved in GnRH receptor binding. Importantly, His², Trp³, and Arg⁸ remain solvent-exposed, whereas the disulfide bond is easily accessible to the solvent, consistent with the proposed drug release mechanism by the thioredoxin system. NMR-restrained molecular modeling confirmed the dominant conformational features predicted by the unconstrained theoretical simulations. Overall, these findings provide better structural understanding of the molecular organization of mitoxantrone–GnRH conjugates, highlighting key receptor-recognition residues and supporting both the proposed thioredoxin-mediated drug release mechanism and their previously reported biological properties. These insights may facilitate the rational design and optimization of improved GnRH peptide–drug conjugates for targeted therapy. Full article

Cellulose acetate (CA) is a promising bio-derived membrane material for water treatment; however, its limited availability of active functional sites can restrict its affinity toward dissolved pollutants. In this study, a cellulose acetate membrane was fabricated by phase inversion and subsequently functionalized through novel direct graft copolymerization with bio-based itaconic acid (IA) using potassium persulfate (KPS) as an initiator in an aqueous medium. The grafting approach introduced carboxylic functional groups into the CA matrix, providing additional active sites for pollutant removal. The successful grafting was confirmed by UV–Vis and 1H NMR spectroscopy, while XRD indicated changes in the structural organization of the polymer matrix. SEM/EDS characterization further revealed morphological changes associated with grafting, and cross-sectional SEM showed the development of finger-like, continuous pore channels within the modified membrane. The effects of reaction time, IA concentration, and KPS concentration on the grafting percentage were systematically evaluated, with grafting increasing up to an optimum range before declining at excessive monomer or initiator concentrations. Thermal analysis demonstrated improved stability after grafting, with the 6.6% grafted CA-g-IA membrane exhibiting an initial decomposition temperature of 351 °C and a reduced weight loss of 85% at 500 °C, compared with 344 °C and 91%, respectively, for pristine CA. The 6.6% CA-g-IA membrane was subsequently evaluated for the removal of Cu(II) and methylene blue (MB) from aqueous solutions. Cu(II) uptake was strongly influenced by contact time, solution pH, initial concentration, and grafting percentage, with the highest performance observed around pH 6 and 240 min contact time. The membrane also maintained its Cu(II)-binding performance over four regeneration cycles following HNO₃ treatment. Overall, direct IA grafting provides a simple bio-based functionalization strategy for enhancing the pollutant-binding functionality of cellulose acetate membranes, demonstrating potential for the removal of metal ions and cationic dyes from contaminated water. Full article

Reaction of 2-(3,5-dichloro-4H-1,2,6-thiadiazin-4-ylidene)malononitrile with sodium 2-aminophenolate (1.5 equiv.) in anhydrous THF at ca. 0–20 °C afforded the known 4-chlorobenzo[5,6][1,4]oxazino[2,3-c][1,2,6]thiadiazine in 76% yield. In contrast, treatment of the same substrate with 2-aminophenol (3 equiv.) in acetonitrile at ca. 20 °C gave 5-cyano-7-(2-hydroxyphenyl)-4-[(2-hydroxyphenyl)amino]pyrrolo[2,3-c][1,2,6]thiadiazin-6(7H)-iminium chloride hydrate in 93% yield. This compound was characterized by ¹H and ¹³C NMR, IR and UV-vis and mass spectrometry, together with melting point and elemental analysis, and its structure was supported by single-crystal X-ray crystallography. Full article

Xishuangbanna (XIS) cucumber (Cucumis sativus) originated from low-altitude southwest China and shows extreme cold sensitivity. Nano-hydroxyapatite (nHAP), known for its high bioavailability and surface reactivity relative to bulk HAP, was applied to enhance the cold tolerance of XIS seedlings. We optimized fertilization timing and fertilizer concentration. By determining physiological parameters alongside gene expression profiling and transcriptomic analysis, we preliminarily dissected the physiological and molecular mechanisms underlying nHAP-enhanced chilling tolerance. nHAP application preserved free and bound water even at 24 h into the cold-stress treatment, as detected by nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI). Exposure to cold stress caused a chilling injury index (CII) of 73.33%, while foliar spraying of nHAP at gradient concentration reduced CII values by 9.09–54.55%. At the same time, electrolyte leakage and malondialdehyde content were decreased by 6.68–61.41% and 12.92–67.16% respectively; chlorophyll content increased by 0.01–73.42%; SOD, POD, and soluble protein content increased by 10.54–161.53%, 16.50–154.33%, and 2.03–63.26%, respectively. Soil application of nHAP showed a similar but weaker effect than foliar spraying on alleviating chilling injury, and the optimal concentration was 1000 mg/L. Quantitative Real-Time PCR (qRT-PCR) revealed that foliar spraying of nHAP upregulated the gene expression of Superoxide dismutase genes (CsCu/ZnSOD and CsMnSOD) and major facility superfamily genes (CsSPX-MFS1 and CsSPX-MFS2) in the cold treatment. We then profiled the transcriptome changes in seedling leaves during the cold treatment after foliar spraying of nHAP. Without nHAP application, cold stress resulted in a total of 6795 differentially expressed genes (DEGs), which were functionally enriched in plant–pathogen interaction and plant hormone signal transduction pathways. Under nHAP application, cold stress only caused 776 DEGs, which were functionally enriched in plant hormone signal transduction and galactose metabolism. These findings suggest that nHAP could improve the cold tolerance of cucumber seedlings through boosting antioxidant activity and plant hormone signaling pathways. Full article

This work presents the synthesis and structural characterization of a previously unknown palladium(II) complex with (2E)-2-[1-(4-aminophenyl)ethylidene]hydrazine-1-carbothioamide, which in the solid state forms a highly symmetric tetrametallic metallamacrocycle. The structure of the synthesized (2E)-2-[1-(4-aminophenyl)ethylidene]hydrazine-1-carbothioamide and corresponding palladium(II) complex was established by ¹H, ¹³C–{¹H}, ¹H–¹³C HMQC, and ¹H–¹³C HMBC NMR spectroscopy; IR and UV spectroscopy; mass spectrometry; TGA/DSC analyses; and single-crystal X-ray diffraction. Full article

1-[(4S)-4-benzyl-1,3-oxazolidin-2-one-3-yl]propyltriphenylphosphonium tetrafluoroborate was synthesized in a two-step procedure starting from (4S)-4-benzyl-3-propionyl-1,3-oxazolidin-2-one. In the first step, (4S)-4-benzyl-3-propionyl-1,3-oxazolidin-2-one was treated with DIBAL-H at −78 °C in DCM and then converted to (4S)-4-benzyl-3-(1-trimethylsilyloxy)propyl-1,3-oxazolidin-2-one with TMSOTf at −78 °C in DCM in the presence of pyridine. Next, the silylated intermediate was transformed to the expected 1-[(4S)-4-benzyl-1,3-oxazolidin-2-one-3-yl]propyltriphenylphosphonium tetrafluoroborate by reaction with Ph₃P·HBF₄ at −40 °C in DCM. The structures of the compounds obtained were confirmed by spectroscopic methods (¹H-, ¹³C{¹H}-, ³¹P{¹H}-NMR, IR) and HRMS analysis. Full article

This work describes the synthesis of 4-methyl-N-(2-methylbenzyl)-N′-(2-methylbenzylidene)benzenesulfonohydrazide. Full characterization of the target compound is achieved through melting point measurement, ¹H NMR, ¹³C NMR spectroscopy and mass spectrometry, with unambiguous structural confirmation provided by single-crystal X-ray diffraction. Aggregated analytical data from multiple characterization techniques confirms successful preparation of the newly synthesized molecule and validates its structural integrity. Full article