Search Results (3,169)

Unconsolidated sandstone gas reservoirs often suffer from near-wellbore plugging, permeability contrast, and sand production after acid stimulation. This study evaluates a staged chemical process that couples limited cationic polymer sand stabilization with reaction-induced self-diverting acidizing, instead of direct premixing or simultaneous co-injection of acid and sand control fluids. Residual acid viscosity tests, core flooding experiments, dynamic sand production tests, scanning electron microscopy/energy-dispersive spectroscopy, and low-field nuclear magnetic resonance measurements were used to investigate viscosity building, diversion, permeability retention, and pore structure evolution. The 5 wt% EAB self-diverting acid exhibited the strongest reaction-induced viscosity-building behavior, reaching a residual acid viscosity of 134 mPa·s. The selected HCl + HF acid system produced a clear temporary-plugging response during core flooding, and the optimized 0.2 wt% cationic polyacrylamide stabilizer increased the critical sand production flow rate to 1.8 mL·min⁻¹ while maintaining acceptable permeability recovery. Microscopic evidence indicates improved pore connectivity without large-scale skeletal collapse. A comprehensive synergy index showed that medium-permeability cores (300–500 mD) achieved the best balance among acid diversion, sand stabilization, and permeability retention. The proposed process provides a laboratory-scale foundation for coupled stimulation and sand control design. Full article

Background/Objectives: This study examined the effect of three different cultural media—coconut coir, peat moss, and deep-water culture—on the metabolomic profiles of two tomato cultivars, Heinz and Roma. Tomato fruit quality is influenced by intricate interactions between the genotype and root-zone environment; nevertheless, little is known about how substrate-based systems compare metabolically to deep-water hydroponics. Methods: Fruit samples from both cultivars grown under controlled greenhouse conditions were analyzed using proton nuclear magnetic resonance (¹H-NMR) spectroscopy to identify treatment-dependent biochemical changes. Polar metabolites were extracted using a methanol–water solvent solution and examined using a 600 MHz NMR spectrometer. Spectral datasets were processed and analyzed with multivariate statistical tools such as Principal Component Analysis (PCA), Partial Least Squares Discriminant Analysis (PLS-DA), and Orthogonal Partial Least Squares Discriminant Analysis (OPLS-DA). Results: Distinct clustering patterns were observed, indicating both cultivar-specific and cultivation-system-dependent metabolic differentiation. The PCA model displayed excellent explanatory and predictive capacity, while supervised OPLS-DA improved group discrimination, demonstrating that both genotype and growing medium significantly influenced the chemical composition of the fruit. Soluble sugars (glucose, fructose, and sucrose), sugar alcohols, organic acids such as citric and malic acids, and a variety of amino acids involved in nitrogen metabolism and stress reactions were among the key distinguishing factors. Carbohydrate-related spectral areas (3.0–5.5 ppm) were highly associated with treatment separation, indicating that the cultivation system had a significant impact on carbon allocation and energy metabolism. Conclusions: Fruits grown in deep water culture have distinct metabolic fingerprints from those grown on coconut coir and peat moss, implying that root-zone oxygen availability and nutrient dynamics may influence primary and secondary metabolism. Full article

Background/Objectives: Kidney transplantation remains the gold standard treatment of end-stage kidney disease; however, its recipients exhibit mixed clinical trajectories, with variable renal function and proteinuria evolution over time. Currently used methods to screen these changes are associated with possible adverse effects and limitations. Methods: In this single-center cohort study, 174 adult kidney transplant recipients were enrolled between January 2024 and January 2025 and followed for 12 months. Patients underwent serum and urinary metabolomic profiling using nuclear magnetic resonance (NMR) spectroscopy. Furthermore, clinical and biological data were collected, allowing for assessment of changes in renal function and proteinuria, with patient stratification based on outcome trends. Results: Serum metabolomic profiles were linked to renal outcomes. For ΔeGFR, valine differed between patients with positive and negative trajectories, while GlycA, GlycB and Glyc/SPC were associated with ΔeGFR in adjusted models. For Δproteinuria, GlycA, VLDL particles and triglycerides showed correlations, while glucose differed between patients with improving and worsening proteinuria. In adjusted models, isoleucine, alanine, GlycA and Glyc/SPC were associated with Δproteinuria. Urinary metabolomic profiles showed fewer associations. Dimethylamine and urinary creatinine were associated with ΔeGFR in adjusted models, while acetic acid differed between proteinuria groups. No urinary metabolite was associated with Δproteinuria after adjustment. Conclusions: Overall, metabolomic changes were connected with renal outcomes in kidney transplant patients, with distinct but partially overlapping patterns for ΔGFR and Δproteinuria. Serum findings were more consistent, while urinary associations were more limited. Further longitudinal and externally validated studies are required to confirm these observations and explore the potential of this metabolomic approach in the search for novel biomarkers. Full article

Flavones are natural substances widely distributed in fruits and vegetable. Their compounds are characterized by a broad spectrum of activities, including antioxidant activity. Their most interesting biological effect, however, is antihyperglycemic activity, mediated by the inhibition of α-glucosidase. A series of 7-hydroxyflavone derivatives was synthesized and comprehensively characterized using nuclear resonance magnetic spectroscopy. The biological potential of the synthesized derivatives was assessed through antioxidant (DPPH) and α-glucosidase inhibitory assays. The physicochemical and pharmacokinetic properties were analyzed using in silico methods. Finally, molecular docking studies were performed to elucidate the binding mode of compounds within the catalytic site of α-glucosidase. Full article

Ultrasonic-assisted heterogeneous Fenton-like (UHEF) pretreatment is an emerging strategy that overcomes the limitations of traditional homogeneous Fenton systems while enhancing the efficiency of lignocellulosic biomass processing. In this study, we constructed a UHEF system employing iron-loaded zeolite as a heterogeneous catalyst to pretreat eucalyptus sawdust (ES). Process conditions were optimized using response surface methodology (RSM) with a central composite design (CCD), yielding a maximum reducing sugar production of 441.45 mg/g. We systematically investigated the mechanism by which UHEF pretreatment enhances the enzymatic hydrolysis of ES through compositional analysis, Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), cross-polarization magic-angle spinning carbon-13 nuclear magnetic resonance (CP/MAS ¹³C NMR), and scanning electron microscopy (SEM). Additionally, recovery and recycling experiments were conducted to evaluate the reusability of the iron-loaded zeolite. XRD, XPS, and ICP-OES were further used to verify the crystalline structure, surface Fe chemical states, and Fe loading of the catalyst, and Fe leaching was quantified for each reuse cycle. The results demonstrated that UHEF pretreatment effectively removed lignin and hemicellulose from ES, disrupted the cellulose crystalline structure, and generated numerous grooves on the substrate surface. These modifications increased the effective adsorption of cellulase and enhanced reducing sugar production to 4.32 times that of raw eucalyptus sawdust (RES). Although the recycling experiments indicated that the stability of the iron-loaded zeolite requires further improvement, the catalyst retained a certain degree of reusability over four consecutive cycles. These findings demonstrate that UHEF pretreatment is a promising approach with broad application prospects in lignocellulosic biorefinery, consistent with recent advances in advanced oxidation processes for biomass valorization. Full article

4′-Hydroxymethoxychalcones represent structurally diverse chalcone derivatives that are attractive substrates for microbial functionalization; however, the impact of methoxy substitution position on their cascade biotransformation by fungi remains poorly understood. In this study, three regioisomeric 4′-hydroxymethoxychalcones, featuring ortho-, meta-, or para-methoxy groups on ring B, were transformed using eight entomopathogenic fungal strains belonging to the genera Beauveria, Isaria, and Metarhizium. Metabolic profiles were monitored over a 10-day period using ultra-high-performance liquid chromatography coupled with diode-array detection (UHPLC-DAD), and the structures of the major products were elucidated primarily by one- and two-dimensional nuclear magnetic resonance (NMR) spectroscopy and further supported by high-resolution electrospray ionization quadrupole time-of-flight mass spectrometry (HR-ESI-QTOF-MS). The investigated microorganisms catalyzed multistep transformations encompassing the reduction of the α,β-unsaturated carbonyl system, methylglucosylation, O-demethylation, and the formation of secondary polar metabolites. Although ene-reduction constituted the predominant initial reaction for all substrates, the relative distribution of subsequent metabolites varied depending on both the fungal strain and, to a lesser extent, the position of the methoxy group. The ortho-methoxy derivative exhibited the highest propensity for O-demethylation; the meta-substituted substrate generated the most heterogeneous secondary metabolite profiles, whereas the para-methoxy analogue showed the most consistent accumulation of methylglucosylated dihydrochalcones. These findings indicate that methoxy substitution position does not alter the common core biotransformation pathway, but can modulate the relative efficiency of individual steps and the extent of secondary metabolism. Full article

Although European oak honeydew honeys have a similar botanical origin, it is unclear if their chemical composition reflects their geographical origin. Sixty samples from Bulgaria, Germany, Greece, Italy, North Macedonia, Romania, Serbia, and Spain were analyzed using semiquantitative ¹³C nuclear magnetic resonance (NMR) spectroscopy. The protected designation of origin (PDO) Strandzha honey was compared to honey from other regions in Bulgaria. The profiles included 25 identified constituents, 21 saccharides, and 16 reproducible unidentified signals. Statistical analysis differentiated country groups through combinations of variables rather than a single marker. A decision tree based on nigerose, fructose, melezitose, panose, sucrose, and one unidentified signal summarized the main differences among the countries. Strandzha honeys exhibited a unique regional profile characterized by higher glucose levels and lower concentrations of several minor saccharides and unidentified signals. Two coordinated saccharide networks revealed that minor sugars fluctuate in linked groups rather than independently. This pattern has not been previously described in European honey. Conventional honeydew-associated indicators varied across the dataset. However, 1-kestose was present in all samples. Nevertheless, its specificity to oak honeydew origin remains unresolved. While extended ¹³C NMR profiling may support geographical characterization, independent validation is required before it can be used for authentication. Full article

Monomer sequence strongly influences copolymer properties, but direct block formation from a monomer mixture requires a large reactivity contrast. Here, fluorination was used to regulate anhydride reactivity in the cesium pivalate-catalyzed ring-opening alternating copolymerization (ROAC) of tetrafluorophthalic anhydride (FPA), phthalic anhydride (PA), and 3-perfluorohexyl-1,2-epoxypropane (PFE). Time-resolved nuclear magnetic resonance (NMR) spectroscopy showed that FPA reached >99% conversion before detectable PA incorporation. With 1,4-benzenedimethanol as a bidirectional initiator, this sequential consumption generated a central poly(FPA-alt-PFE) segment followed by poly(PA-alt-PFE) growth from both chain ends. Molar mass evolution, end-group analysis, and diffusion-ordered spectroscopy (DOSY) NMR collectively supported covalent block formation. Sequential incorporation was retained across three different FPA:PA feed ratios, and Beckingham–Sanoja–Lynd analysis yielded large and reciprocal effective reactivity-ratio descriptors ($r_{\mathrm{F}\mathrm{P}\mathrm{A}}\approx 8.3–8.6\times {10}^2$ and $r_{\mathrm{P}\mathrm{A}}\approx 1.2\times {10}^{-3}$), consistent with the experimentally observed real-block regime. Matched model reactions further indicated faster FPA ring-opening and higher observed epoxide-opening reactivity in a fluorinated aromatic carboxylate model system. These results demonstrate that H-to-F substitution can provide the kinetic bias required to program block copolyester sequence within a single ROAC platform. Full article

Organic phosphorus (OP) transformation in perennial orchard soils is strongly regulated by planting duration. However, the pathways of soil OP turnover in the orchards with different planting years remain largely unknown. This study was conducted in Penglai District, Shandong Province, China, characterized by a warm-temperate continental monsoon climate and brown sandy loam soil. Soil samples were collected from the 0–20 cm layer of vineyards established for 0.5, 4, 16, and 22 years (Y0.5, Y4, Y16, and Y22, respectively). Soil P pools, OP forms determined by solution ³¹P nuclear magnetic resonance spectroscopy, acid and alkaline phosphomonoesterase (ACP and ALP), phosphodiesterase (PDE) activities, and the diversity and composition of phoC- and phoD-harboring bacterial communities were analyzed. Differences among vineyard ages were assessed using one-way ANOVA, while principal coordinate analysis, canonical correlation analysis, and structural equation modeling were employed to evaluate microbial community variation and the relationships among soil properties, functional bacterial communities, phosphatase activities, and OP forms. We observed that compared with that in Y0.5, total P content in Y4 was significantly lower, whereas available P (AP) content in Y16, and OP content in both Y16 and Y22, were significantly higher. The contents of orthophosphate, myo-inositol hexakisphosphate (myo-IHP), scyllo-IHP, choline phosphate and corrected monoester (cMonoester) in Y16 and Y22 were significantly higher than that in Y0.5. Soil ACP activity in Y16 was significantly higher than that in Y4, but ALP and PDE activities in Y16 were significantly lower than those in other planting years. The phoC- and phoD-harboring community composition in Y16 was significantly altered, with phoC- and phoD-harboring community α-diversity remarkably increased and decreased, respectively. The phoC- and phoD-harboring community composition was driven by soil pH, AP and cMonoester, with phoD-harboring community composition predicted by the soil C:P ratio. Soil OP transformation is mainly regulated by the activity of PDE and ACP, and the diversity and composition of phoC-harboring communities, in orchards with different planting years. Full article

Fucoidans are sulphated polysaccharides from brown macroalgae that have attracted considerable interest due to their diverse biological activities and potential applications in metabolic health. In this study, fucoidan-rich extracts were obtained from three South African brown macroalgal species, Ecklonia maxima, Ecklonia radiata, and Sargassum incisifolium, and comparatively characterised using biochemical and physicochemical analyses. The extracts were evaluated for carbohydrate, sulphate, L-fucose, protein, polyphenol, and uronic acid contents, while molecular weight distribution, Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and proton Nuclear Magnetic Resonance (¹H NMR) spectroscopy were used to investigate structural characteristics. All extracts displayed features characteristic of fucoidans, including sulphated fucose-containing polysaccharides. Notable species-dependent differences were observed, with S. incisifolium exhibiting the highest sulphate (~24%) and polyphenol (~6.76%) contents, stronger sulphate-associated FTIR signals, greater molecular weight heterogeneity, and enhanced thermal stability. The fucoidan-rich extracts exhibited concentration-dependent pancreatic lipase and α-glucosidase inhibitory activities, together with DPPH radical-scavenging activity. At 1.0 mg/mL, S. incisifolium demonstrated approximately 66% DPPH radical scavenging and 49% pancreatic lipase inhibition. S. incisifolium and E. radiata exhibited strong α-glucosidase inhibition, with IC₅₀ values of ~29 and ~46 µg/mL, respectively, compared to ~354 µg/mL for acarbose. The findings highlight South African brown macroalgae as promising sources of fucoidans and contribute to understanding the relationships among fucoidan composition, structure, and bioactivity. Full article

Solid electrolyte interphase (SEI) characterization is needed to interpret the performance, degradation, and lifetime of graphite and Si-containing carbon-based negative electrodes in lithium-ion batteries. However, SEI claims are often difficult to compare because measured signals, inferred assignments, sample history, and electrode architecture are not always clearly separated. This review presents a claim-bounded framework for SEI characterization that distinguishes direct observables from inferred chemical, molecular, structural, morphological, and functional information. Photoelectron spectroscopy methods provide chemical-state and relative-depth-sensitivity constraints; secondary-ion mass spectrometry methods provide fragment and isotope distributions; vibrational spectroscopies support functional-group and local vibrational evidence; nuclear magnetic resonance and molecular mass spectrometry provide molecular or product-level constraints; and microscopy, tomography, and atomic force microscopy provide morphology, architecture, local thickness, topography, and mechanical response. Across these methods, rinsing, drying, sputtering, beam exposure, extraction, and limited sampling can alter the observable and therefore the defensible claim. The review emphasizes the distinction between native electrode-associated SEI features and extracted, soluble, or electrolyte-phase products, and between morphology-only evidence and chemically assigned morphology. It concludes by proposing claim-driven correlative workflows and reporting guidance for reproducible interpretation on graphite, Si/graphite, Si/C, and carbon-coated Si architectures where directly studied or present. Full article

Frozen seafood plays an important role in the global food supply, but maintaining its quality during frozen storage and cold-chain distribution remains a significant challenge. Although freezing effectively slows microbial growth and enzymatic activity, it cannot completely prevent quality deterioration. During frozen storage, seafood undergoes a series of interconnected physicochemical changes, including ice crystal growth, protein denaturation and oxidation, lipid oxidation, water redistribution, and texture deterioration. These changes gradually reduce sensory quality, nutritional value, and overall commercial acceptability. Conventional quality assessment methods, including destructive laboratory analyses and sensory evaluation, are still widely used. However, they are often labor-intensive, time-consuming, and unsuitable for rapid or real-time monitoring in modern cold-chain systems. As a result, increasing attention has been given to non-destructive sensing technologies that can evaluate seafood quality quickly and objectively. This review summarizes the major mechanisms responsible for quality deterioration in frozen seafood, together with recent advances in sensing technologies used to monitor these changes. The sensing approaches discussed include near-infrared (NIR) and Raman spectroscopy, hyperspectral and fluorescence imaging, low-field nuclear magnetic resonance (LF-NMR), electronic nose (E-nose), electronic tongue (E-tongue), colorimetric sensor arrays (CSAs), and biosensors. This review also discusses the growing role of artificial intelligence in frozen seafood quality assessment, including chemometrics, machine learning, deep learning, and multi-sensor data fusion. Particular attention is given to their applications in quality prediction, industrial implementation, and decision support. Finally, current challenges and future research needs are highlighted, with emphasis on the development of interpretable, transferable, and real-time monitoring systems that can support more reliable quality assurance throughout the frozen seafood supply chain. Full article

In contrast to honeybees, the Australian stingless bee Tetragonula carbonaria appears to be robust against microbial pathogens. Streptomyces sp. 127Q, isolated from T. carbonaria, inhibited the growth of Lysinibacillus sphaericus, which is the only microorganism reported to affect T. carbonaria. The antimicrobials were purified from Streptomyces sp. 127Q by bioassay-guided isolation using ethyl acetate extraction and Diaion HP20 chromatography, followed by reverse phase HPLC fractionation. The antimicrobial compounds were identified by high-resolution mass spectrometry, UV-Vis-spectroscopy, nuclear magnetic resonance spectroscopy, and genome mining as new members of the trioxacarcin/gutingimycin family having a 1,2-dihydroxyanthraquinone aromatic core structure. A closely related gutingimycin with a 1,2-dihydroxyanthraquinone moiety was previously observed in a crystallisation experiment of trioxacarcin A with an oligonucleotide. Streptomyces sp. 127Q produces a wide range of trioxacarcins/gutingimycins. At the onset of trioxacarcins production, Streptomyces sp. 127Q appeared to rapidly convert trioxacarcin epoxides with water, guanine, and nicotinic acid. The 1,2-dihydroxyanthraquinone trioxacarcins, trioxacarcin 692 and trioxacarcin 780, inhibited L. sphaericus with minimal inhibitory concentrations (MICs) of 37.5 μM and 75 μM, respectively. The MIC against Escherichia coli and Staphylococcus aureus was 75 μM and 150 μM, respectively. In the photoantimicrobial screening, the MIC for trioxacarcin 692 against E. coli and S. aureus decreased by 8-fold, and for trioxacarcin 780 by 4-fold. Following light pretreatment, trioxacarcin 692 (9.4 μM) inhibited E. coli and S. aureus at concentrations comparable to those of the established antibiotics ciprofloxacin and vancomycin. Neisseria gonorrhoeae was only inhibited at an MIC of ca. 18.8 μM after light preincubation. The 1,2-dihydroxyanthraquinone trioxacarcins constitute powerful antimicrobial compounds belonging to the trioxacarcin/gutingimycin family. Full article

The structural and immunomodulatory properties of arabinogalactan proteins (AGPs) from edible medicinal plants remain largely unexplored. Here, A homogenous AG-II-like arabinogalactan protein (CTSP-W2, 9862 Da) was isolated from Cynanchum thesioides via hot-water extraction, ethanol precipitation, and column chromatography. Its structure was thoroughly characterized by high-performance gel permeation chromatography (HPGPC), Fourier-transform infrared spectroscopy (FT-IR), nuclear magnetic resonance (NMR), Congo-red, scanning electron microscopy (SEM), sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), methylation analysis. The mechanism of immune activity was examined using specific inhibitors, Western blotting, and molecular docking. It comprises galactose, arabinose, glucose, galacturonic acid, xylose, and 18 amino acids (asparagine-rich), with a backbone of →3,6)-Galp-(1→ and →6)-Galp-(1→. CTSP-W2 significantly enhanced macrophage proliferation, phagocytosis, and secretion of Nitric oxide (NO), Tumor necrosis factor-alpha (TNF-α), and Interleukin-6 (IL-6). Inhibitor assays showed that Toll-like receptor 4 (TLR4, TAK-242) and Toll-like receptor 9 (TLR9, E6446) antagonists markedly reduced CTSP-W2-induced TNF-α, IL-6, and NO in a dose-dependent manner, whereas Toll-like receptor 2 (TLR2) inhibition (C29) unexpectedly upregulated these mediators. Western blot revealed that CTSP-W2 upregulated TLR4 and TLR9 protein expression and increased phosphorylation of Inhibitor of nuclear factor kappa-B alpha (IκBα), nuclear factor kappa B (NF-κB p65), and p38, indicating activation of the TLR4/9–NF-κB–p38 mitogen-activated protein kinase (MAPK) signaling axis. Furthermore, Molecular docking analysis further indicated that CTSP-W2 forms extremely strong hydrogen-bonding and hydrophobic interactions with TLR4 through its galactose chains. This study elucidates the immunoregulatory mechanism of CTSP-W2 and establishes a molecular basis for arabinogalactan proteins as potential natural immunomodulators. Full article

Polyhydroxyalkanoates (PHAs) are biodegradable microbial polyesters that may reduce dependence on petroleum-derived plastics, but broader use remains constrained by production costs and tightly controlled cultivation. Thermophilic microorganisms have attracted increasing attention as promising PHA producers because they can be cultivated at elevated temperatures, reducing contamination risks and operational costs. In this study, a thermophilic Geobacillus sp. strain SL28 isolated from a Vietnamese hot spring was evaluated for its PHA-producing capability. Temperature, initial pH, carbon and nitrogen sources, C/N ratio, and cultivation time were examined. Intracellular inclusions were assessed by Sudan Black B and Nile Blue A staining and transmission electron microscopy, whereas the recovered polymer was characterized by FE-SEM, Fourier-transform infrared spectroscopy (FTIR), gas chromatography–mass spectrometry (GC–MS), ¹H- and ¹³C-nuclear magnetic resonance (NMR) spectroscopy, capillary viscometry, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and tensile testing. Under the optimized cultivation conditions identified by one-factor experimentation (50 °C, pH 7.0, sucrose, peptone, C/N 25:1, and 72 h), SL28 reached a dry cell weight of 2.215 ± 0.16 g/L and a PHA concentration of 1.383 ± 0.04 g/L, equivalent to 62.57 ± 2.82% of DCW. Structural characterization confirmed that the recovered polymer was poly(3-hydroxybutyrate) (PHB). The purified PHB also exhibited favorable thermal stability, a relatively high molecular weight, and satisfactory mechanical properties. These results demonstrate the potential of thermophilic Geobacillus sp. SL28 as a promising candidate for PHB production. Full article