Search Results (2,357)

Isoegomaketone [(E)-1-(furan-3-yl)-4-methylpent-2-en-1-one; 1] is abundant in the essential oil of Perilla species and exhibits various biological activities, such as anticancer and anti-inflammatory effects. In order to discover compounds with reduced toxicity or enhanced biological activity through structural modification of natural product-derived components, isoegomaketone was irradiated with an electron beam at five different doses, and (±)-8-methoxy-perilla ketone (2) was obtained with the highest yield of 3.8% (w/w) at 80 kGy. Its structure was identified by one-dimensional and two-dimensional nuclear magnetic resonance spectroscopy and high-resolution chemical ionization mass spectrometry. Compound 2 inhibited nitric oxide production and inducible nitric oxide synthase mRNA expression in a dose-dependent manner in lipopolysaccharide-stimulated RAW 264.7 cells. It also dose-dependently suppressed the mRNA expression of pro-inflammatory mediators such as IL-1β, IFN-β, and MCP-1, while having no significant effect on IL-6 mRNA levels. Furthermore, ELISA analysis demonstrated that 2 reduced MCP-1 protein expression but did not affect the protein level of TNF-α or IL-6. This study provides a reference for the structural analysis of compounds related to 2 by presenting NMR data acquired with chloroform-d, and is the first to report the anti-inflammatory properties of 2. Full article

Thiosemicarbazones and thiocarbohydrazones are key sulfur-containing organic compounds known for their diverse biological, pharmaceutical, and industrial applications. Beyond their well-established therapeutic potential, their strong chelating ability allows them to form stable complexes with transition metals, enabling uses in catalysis, corrosion inhibition, and dyeing processes. Their structural characteristics and dynamic conformations critically influence both biological activity and industrial performance, making nuclear magnetic resonance (NMR) spectroscopy an indispensable tool for their analysis. This review provides a comprehensive overview of the conformational and functional properties of bioactive thiosemicarbazones and thiocarbohydrazones, with a focus on how experimental NMR techniques are used to investigate their conformational behavior. In addition to experimental findings, available computational data are discussed, offering complementary insights into their structural dynamics. The integration of experimental and theoretical approaches offers a robust framework for predicting the behavior and interactions of these compounds, thereby informing the rational design of novel derivatives with improved functionality. By highlighting key structural features and application contexts, this work addresses a critical gap in the current understanding of these promising agents across both biomedical and industrial domains. Full article

Tokamak technology, as the cornerstone of nuclear fusion energy, holds immense potential in achieving efficient plasma confinement and high energy densities. To comprehensively map the rapidly evolving landscape of this field, this study employs bibliometric analysis to systematically examine the research and development trends of tokamak technology from 2014 to 2024. The data are drawn from 7702 academic publications in the Scopus database, representing a global research effort. Additionally, the study incorporates 2299 tokamak-related patents from Google Patents over the same period, analyzing their technological trends to highlight the growing significance of tokamak devices. Using the R language and the Bibliometric package, the analysis explores research hotspots, institutional influences, and keyword evolution. The results reveal a multifaceted global landscape: China leads in publication output, and the United States maintains a leading role in citation impacts and technological innovation, with other notable contributions from Germany, Japan, South Korea, and various European countries. Patent trend analysis further reveals the rapid expansion of tokamak applications, particularly with significant innovations in high-temperature superconducting magnets and plasma control technologies. Nevertheless, the study identifies major challenges in the commercialization process, including plasma stability control, material durability, and the sustainability of long-term operations. To address these, the study proposes concrete future directions, emphasizing international collaboration and interdisciplinary integration. These efforts are crucial in accelerating tokamak commercialization, thereby providing a strategic roadmap for researchers, policymakers, and industry stakeholders to advance the global deployment of clean energy solutions. Full article

To address the issues of poor thermal stability, inadequate salt tolerance, and environmental risks in conventional gel systems for the development of high-temperature, high-salinity heterogeneous reservoirs, a triple-synergy gel system comprising anionic polyacrylamide (APAM), polyethyleneimine (PEI), and phenolic resin (SMP) was developed in this study. The optimal synthesis parameters—APAM of 180 mg/L, PEI:SMP = 3:1, salinity of 150,000 ppm, and temperature of 110 °C—were determined via response surface methodology, and a time–viscosity model was established. Compared with existing binary systems, the proposed gel exhibited a mass retention rate of 93.48% at 110 °C, a uniform porous structure (pore size of 2–8 μm), and structural stability under high salinity (150,000 ppm). Nuclear magnetic resonance displacement tests showed that the utilization efficiency of crude oil in 0.1–1 μm micropores increased to 21.32%. Parallel dual-core flooding experiments further confirmed the selective plugging capability in heterogeneous systems with a permeability contrast of 10:1: The high-permeability layer (500 mD) achieved a plugging rate of 98.7%, while the recovery factor of the low-permeability layer increased by 13.6%. This gel system provides a green and efficient profile control solution for deep, high-temperature, high-salinity reservoirs. Full article

The consumption of animal- and plant-based protein food is increasing as the world population grows. Alternative protein sources that are nutritious, safe and sustainable are needed. There is a growing research interest in integrating wheat-based staple foods, such as pasta, with new ingredients that could also provide nutritional and health benefits. Despite their unquestionable nutritional value, new pasta formulations need to be evaluated in terms of technological/sensory quality. In this study, we assessed the quality and flavour of traditional egg pasta fortified with two alternative protein sources: hazelnut flour and cricket powder. It is known that a quality pasta tends to lose fewer solids during cooking. In parallel with classical evaluation of cooking and sensory characteristics, proton nuclear magnetic resonance (¹H NMR) spectroscopy of the metabolites released during the cooking process and volatile fingerprint analysis with quartz microbalance (QMB) electronic nose (E-nose) were performed. These approaches showed results complementary to those obtained from classical quality and sensory analyses, thus demonstrating the potential of ¹H NMR and E-nose in pasta quality assessment. Overall, the pasta fortification with cricket powder and hazelnut flour affected the matrix mobility by modulating the release of chemical components into the water during cooking and overcooking processes; moreover, it significantly altered the pasta sensory profile in terms of aroma and texture. This finding highlights the complexity of balancing technological improvement with sensory appeal in food product development. Full article

Because allopregnanolone and derivatives represent biologically active molecules, in this letter, we present the synthesis of a new bioconjugate steroid pyridinium salt derived from allopregnanolone in three steps. The key steps involve the formation of the hydrazone intermediate, followed by condensation with bromoacetyl bromide and subsequent coupling with pyridine to generate the pyridinium bromide salt. The new bioconjugate steroid pyridinium salt, 4, was fully characterized by proton and carbon nuclear magnetic resonance (¹H and ¹³C NMR) spectroscopy, mass spectrometry (MS), and Fourier transform infrared spectroscopy (FTIR). ¹H-NMR analysis revealed the presence of a dynamic rotameric mixture in a 7:3 ratio of Z/E amide conformers, which were identified by a 2D NOESY experiment. Full article

Background: Metabolomics is a powerful tool used for the evaluation of sugarcane components which are key factors influencing its response to biotic and abiotic stresses. However, little is known about the compositional variability and diversity of the sugarcane juice metabolome under practical field conditions in temperate climates. Methods: In this study, we characterized metabolomic differences and variability in sugarcane juice components during the maturation stage of nine cultivars grown in a temperate climate in Japan using a nuclear magnetic resonance-based metabolomics approach, aiming to provide insights into genotype-dependent adaptability to environmental and climate changes. Results: Principal component analysis revealed distinct metabolic profiles based on cultivar and maturation level. Notably, sucrose levels increased from September to December accompanied by decreased glucose and fructose levels across all cultivars. Early-maturing cultivars had high sucrose content even with shorter growing periods, suggesting particular advantages for sugar production in temperate climates. Additionally, 4-aminobutyric acid accumulated in all cultivars as maturation progressed. On the other hand, trans-aconitic acid, choline, and branched-chain amino acids showed cultivar-dependent trends. In one example, choline concentrations increased significantly in specific cultivars during maturation. Conclusions: These findings support a deeper understanding of metabolic adaptation and may aid in identifying cultivars better suited to environmental fluctuations. Full article

Phytopathogenic fungi secrete numerous effector proteins to disrupt plant defenses. At present, their sequence–structure–function relationships remain poorly understood owing to their diversity. Comprehensive understanding of conserved effectors is necessary to elucidate the molecular relationship between fungi and plants. To fill this research gap, we investigated the Colletotrichum higginsianum effector candidate (ChEC)-88 specifically expressed during infection. Notably, similar to the biotrophy-associated secreted protein 3 (BAS3) from Pyricularia oryzae, ChEC88 inhibited plant cell death caused by necrosis- and ethylene-inducing peptide 1-like protein (NLP1). Nuclear magnetic resonance analysis results revealed that ChEC88 adopted a novel pseudo two-fold symmetrical three-dimensional structure. Homology modeling suggested that BAS3 exhibited a ChEC88-like conformation despite sharing less than 50% sequence identity. Through PSI-BLAST searches, we found that ChEC88 homologs were conserved in various hemibiotrophic phytopathogenic fungi, including Colletotrichum, P. oryzae, and Fusarium species. Functional assays demonstrated that all of the representative homologs suppressed NLP1-induced plant cell death. Mutation experiments identified the residues critical for ChEC88 function. Overall, our findings suggest that hemibiotrophic phytopathogenic fungi share a conserved immune-suppression strategy mediated by ChEC88-like proteins and that such effectors possibly originated from a common ancestral lineage of phytopathogenic fungi. Full article

In this study, we aimed to determine the chemical constituents of M. seguinii, which led to the isolation and identification of 26 compounds. Three new prenylated dihydrobenzofurans [myrsinoic acids I (1), J (2), and K (3)] and a new flavonoid glycoside, mearnsetin 3-O-α-L-arabinopyranoside (4), were discovered, and the absolute configuration of the known compound, myrsinoic acid B (5), was re-established. To ensure the structural accuracy of these compounds, comprehensive spectroscopic analyses were performed, including one- and two-dimensional nuclear magnetic resonance spectroscopy, mass spectrometry, and circular dichroism spectroscopy. In addition, computational analysis methods such as density functional theory (DFT)-based Electronic Circular Dichroism (ECD) simulations and Gauge-Including Atomic Orbitals (GIAOs) ¹H and ¹³C NMR chemical shift calculations with DP4+ probability analysis were utilised to further support the structural assignments. Full article

This study focuses on the complex pore structure and pronounced heterogeneity of tight sandstone reservoirs in the Linxing area of the Ordos Basin and develops a multi-scale quantitative characterization approach to investigate the coupling mechanism between pore structure and reservoir properties. Six core samples were selected from the Shiqianfeng Formation (depth interval: 1326–1421 m) for detailed analysis. Cast thin sections and scanning electron microscopy (SEM) experiments were employed to characterize pore types and structural features. Nuclear magnetic resonance (NMR) experiments were conducted to obtain T₂ spectra, which were used to classify bound and movable pores, and their corresponding fractal dimensions were calculated separately. In addition, NMR logging data from the corresponding well intervals were integrated to assess the applicability and consistency of the fractal characteristics at the logging scale. The results reveal that the fractal dimension of bound pores shows a positive correlation with porosity, whereas that of movable pores is negatively correlated with permeability, indicating that different scales of pore structural complexity exert distinct influences on reservoir performance. Mineral composition affects the evolution of pore structures through mechanisms such as framework support, dissolution, and pore-filling, thereby further enhancing reservoir heterogeneity. The consistency between logging responses and experimental observations verifies the regional applicability of fractal analysis. Bound pores dominate within the studied interval, and the vertical variation of the PMF/BVI ratio aligns closely with both the NMR T₂ spectra and fractal results. This study demonstrates that fractal dimension is an effective descriptor of structural characteristics across different pore types and provides a theoretical foundation and methodological support for the evaluation of pore complexity and heterogeneity in tight sandstone reservoirs. Full article

Metabolomics, a promising field in the realm of omics, focuses on the investigation of alterations and patterns in the composition and abundance of metabolites generated by organisms under perturbation, directly linking measurable chemical reactions with biological events. Its research philosophy aligns harmoniously with the holistic perspective and syndrome differentiation and treatment principles of traditional Chinese medicine (TCM). Consequently, metabolomics has garnered unparalleled attention and has been widely applied in various fields of TCM research such as disease diagnosis, effective constituents and mechanism related with efficacy. In recent years, nuclear magnetic resonance (NMR)-based metabolomics, a non-destructive testing technique, has played a crucial role in metabolomics research, owing to its exceptional repeatability, stability, and advantages in qualitative and quantitative aspects. Through reviewing relevant literature in recent years, this article provides a comprehensive analysis of the fundamental principles of NMR metabolomics technology and its utilization in TCM. Additionally, it examines the challenges encountered in this field and explores potential future development trends, aiming to offer substantial support for further investigations in the realm of TCM metabolomics. Full article

Alzheimer’s disease is the most widespread neurodegenerative disease in the world. Galantamine hydrobromide (GH) is one of the drugs used to treat mild to moderate dementia of the Alzheimer type. Due to the fact that the specificity of the disease requires maximally facilitated intake, orodispersible films present such an opportunity. In the present study orodispersible films based on poly(2-ethyl-2-oxazoline) as well as partially hydrolyzed poly(2-ethyl-2-oxazoline) were prepared and studied as delivery systems for GH. Two samples of partially hydrolyzed PEtOx were synthesized—one of relatively low degree of hydrolysis and another one of relatively high degree of hydrolysis, and studied by Nuclear Magnetic Resonance (NMR). Cytotoxicity assay was performed that validated the low hydrolyzed derivative as biocompatible polymer that maintained desirable physicochemical characteristics without compromising the safety, thereby it was selected for further research. The films were prepared by the solution casting method and characterized by different methods. FTIR was used to determine the potential interactions between the galantamine molecule and the film components. Based on the Thermogravimetric Analysis (TGA) conducted, it was concluded that all films were sufficiently thermally stable, as the component decomposition stage (after initial solvent removal) began above 180 °C. The polymer films were further characterized with the determination of Shore hardness and the results showed that the films containing glycerol as a plasticizer exhibited higher hardness compared to those with PEG as a plasticizer. The disintegration time of the films was determined visually using Petri dishes and it was found that the films disintegrated within the range of 0.52 to 1.58 min, fully meeting the pharmacopoeial requirements. GH release profiles in PBS at 37 °C were obtained, and it was found that by the second minute, 80–90% of the drug were released from the different films, and the release followed an anomalous diffusion mechanism (Case II). Full article

Produced water, a byproduct of oil and gas extraction, poses significant environmental challenges due to its complex composition and high salinity. Conventional treatment technologies often struggle to achieve efficient contaminant removal while maintaining long-term operational stability. Membrane-based separation processes, particularly forward osmosis (FO), offer a promising alternative due to their low hydraulic pressure requirements, high selectivity, and ability to mitigate fouling and scaling effects. This study fabricated and evaluated a novel dual-layer zwitterion-modified electrospun nanofibrous membrane for enhanced produced water (PW) treatment. The dual-layer design consists of a highly porous electrospun nanofibrous support layer for improved permeability and mechanical strength, coupled with a zwitterionic-modified selective layer to enhance antifouling properties and selective contaminant rejection. The zwitterionic surface modification imparts superior hydration capacity, reducing organic and biological fouling while improving water transport efficiency. The membranes are characterized using scanning electron microscopy (SEM), thermogravimetric analysis (TGA), Fourier Transform Infrared (FTIR) spectroscopy, X-ray diffraction (XRD), contact angle and tensile strength measurements, and nuclear magnetic resonance (NMR) spectroscopy to assess their morphological, structural, and chemical properties. The performance evaluations demonstrated significantly higher water flux (up to 16.05 L m⁻² h⁻¹ for SPW (synthetic produced water) and 6.00 L m⁻² h⁻¹ for PW using NaBr) and excellent solid rejection (up to 96.02% for SPW and 88.90% for PW), reduced concentration polarization, and superior antifouling performance compared to conventional FO membranes. Experimental results from bench-scale trials demonstrate that this advanced membrane technology offers enhanced water recovery and contaminant removal efficiency, making it a viable solution for industrial-scale PW treatment and reuse. The findings underscore the potential of next-generation dual-layer FO membranes in promoting sustainable water resource management within the oil and gas sector while minimizing environmental impact. Full article

Functional hydrogels have significant potential for applications in the pharmaceutical, agricultural, and environmental sectors. This study focuses on the synthesis of polyampholytic hydrogels through free radical polymerization using functionalized chitosans. The chitosan was modified with mono and disulfonic groups at different temperatures (25 °C and 60 °C) and reaction times (1, 8, 24 h), followed by further modification with glycidyl methacrylate to introduce vinyl groups into the polymers structure. The modified polymers were analyzed using proton nuclear magnetic resonance, Fourier transform infrared, scanning electron spectroscopy, thermogravimetric analysis, and solubility tests. Specifically, 0.74 mmol/g and 1.58 mmol/g of the primary amine groups available in the chitosan chain (out of a total of 4.93 mmol/g) were substituted with mono- and disulfonic groups, respectively. Following treatment with glycidyl methacrylate, 3.39 mmol/g and 2.21 mmol/g of the remaining primary amine groups in the mono- and disulfonic polymers, respectively, were substituted. The hydrogels obtained by the modified polymers at optimal conditions of 1 h and 25 °C, were characterized by the techniques already mentioned in addition to rheological tests, and water absorption studies across different pHs. The hydrogels demonstrated potential for environmental remediation, particularly in adsorptions of ciprofloxacin (CPX) and copper (Cu²⁺) from aqueous solutions at pH 7, achieving adsorption efficiencies of 24–25% for CPX and 83% for Cu²⁺. The results suggest that the synthesized hydrogels could provide an eco-friendly and efficient solution to challenges in wastewater treatment. Full article

The development of molecules that interact with G-quadruplex (G4) sequences requires effective evaluation methods. Several techniques are currently available, including nuclear magnetic resonance (NMR) spectroscopy and X-ray crystallography, surface plasmon resonance (SPR), isothermal titration calorimetry (ITC) and mass spectrometry (MS), fluorescence using FRET-melting, G4-fluorescent intercalator displacement assay (G4-FID) and affinity chromatography. Among these, CD spectroscopy is gaining prominence due to its lower material requirements, faster experimentation and quicker data processing. However, conventional CD methods have limitations, such as higher sample volume required and the inability to handle high-throughput analysis efficiently. The use of synchrotron radiation in high-throughput analysis methods (HT-SRCD) has further advanced the investigation of small-molecule interactions with DNA G4 structures in the presence of various monovalent cations. HT-SRCD offers the capability to analyze multiple samples simultaneously, overcoming the limitations of conventional CD methods. To validate this approach, three biologically relevant G4 sequences—HTelo1, G3T3 and T95-2T—were investigated. Their interactions with a library of small tetrazole-based molecules, synthesized via a four-component Ugi reaction, and with a peptide sequence deriving from RHAU helicases (Rhau25), were evaluated. The results demonstrate that this method not only effectively discriminates between different ligands but also provides valuable insights into the selectivity and the modes of interaction of these ligands with the G4 sequences. Full article