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In order to determine the influence of different factors on the CO2 huff-and-puff displacement effect, a CO2 huff-and-puff experiment was carried out with Chang 6 tight sandstone samples in Ordos Basin as the research object. Combined with nuclear magnetic resonance technology, the influences of injection pressure, cycle numbers and soaking time on the CO2 huff-and-puff effect were evaluated, and the optimal CO2 huff-and-puff parameters were optimized. The microscopic degree of crude oil production in different scale pores was quantitatively characterized. The results show that the injection pressure and the cycle numbers have a significant influence on the effect of CO2 huff-and-puff. With the increase of injection pressure, huff-and-puff cycle numbers and soaking time, the recovery efficiency increases, but the growth range decreases. When the injection pressure is increased from 6 to 12MPa, the degree of pore mobilization in the oil in macro and medium pores (≥ 10ms) increases by 13.0%-22.63%. The recovery efficiency of a single round gradually decreased with the increase of huff-and-puff rounds. The first cycle of CO2 huff-and-puff was the main contribution of crude oil recovery. However, the production effect of micro and small pores (< 10ms) was significantly improved after multiple cycle numbers of CO2 huff-and-puff. When the soaking time increases from 6 to 24h, the recovery efficiency increases by 11.47%-14.93%. After that, the influence of prolonged soaking time on the porosity production degree of cores with different permeability decreases. It is found that medium pores and macro pores are the main contributors to pore mobilization during multiple cycles of CO2 huff-and-puff. [ABSTRACT FROM AUTHOR]

BACKGROUND: Loquat peel, often as food waste, is a valuable source of bioactive polysaccharides. However, study of such polysaccharides is insufficient, leaving a significant gap in understanding their preparation, structure and bioactivities. RESULTS: In this study, three types of loquat peel polysaccharides (LPWP, LPHP and LPNP) were sequentially extracted using hot water, HCl and NaOH solutions, respectively. Among them, LPWP was the purest, with a yield of 3.4% and molecular weight of 470.6 kDa, and it differed from LPHP and LPNP in structure, as evidenced by Fourier transform infrared spectroscopy, X‐ray diffraction and scanning electron microscopy, which demonstrated that LPWP consisted of more arabinose (Ara) but less galacturonic acid, rhamnose and galactose, with molar percentages of 71.3%, 23.3%, 3.5% and 1.9%, respectively. Besides, LPWP also exhibited superior antioxidant and antihyperglycemic activities in vitro, particularly in inhibiting α‐amylase and α‐glucosidase. Methylation and nuclear magnetic resonance analysis confirmed that LPWP was a methyl‐esterified pectic polysaccharide rich in branched arabinan, as evidenced by the notable proportion of α‐Ara residues, including T‐α‐Araf, 1,5‐α‐Araf and 1,2,3,5‐α‐Araf, with molar percentages of 27.1%, 23.1% and 10.2%, respectively. AFM imaging further revealed its branched‐chain morphology and aggregation behavior. CONCLUSION: This study highlights the potential of loquat peel polysaccharides as a bioactive ingredient with significant antioxidant and antihyperglycemic properties, particularly LPWP, which was found as a methyl‐esterified pectic polysaccharide with abundant‐branched arabinan. Our work provides valuable insights into the application of loquat peel polysaccharides in functional foods. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

This work leverages aperture size-electrostatic potential matching in a robust and scalable MOF to achieve selective and reversible binding of C 3 F 6 through hydrogen bonding while efficiently excluding larger C 3 F 8 molecules. This innovative material overcomes the typical trade-off between low-pressure capacity and selectivity observed in traditional adsorbents. [Display omitted] The sequestration of trace hexafluoropropylene (C 3 F 6) is a critical yet formidable task in the production of high-purity perfluoropropane (C 3 F 8), an important perfluorinated electronic specialty gas (F-gas) in the advanced electronics industry. Traditional adsorbents struggle with uneven, low-pressure uptake and compromises in selectivity. This work utilizes aperture size-electrostatic potential matching within a robust metal–organic framework (Al-PMA) to facilitate selective, reversible binding of C 3 F 6 while excluding larger C 3 F 8 molecules. The presence of bridging hydroxyl groups (μ 2 -OH) in Al-PMA creates positive electrostatic potential traps that securely anchor C 3 F 6 through strong hydrogen bonding, evidenced by in-situ infrared and 19F magic angle spinning nuclear magnetic resonance spectroscopy. Breakthrough experiments demonstrate the efficient removal of trace C 3 F 6 from C 3 F 8 under ambient conditions, achieving C 3 F 8 purity exceeding 99.999%. The scalability of Al-PMA synthesis, remarkable stability, and exceptional performance highlight its potential as a promising adsorbent for industrial C 3 F 6 /C 3 F 8 separations. [ABSTRACT FROM AUTHOR]

Background: Alzheimer's disease (AD) is the most frequent neurodegenerative disorder worldwide. The great variability in disease evolution and the incomplete understanding of the molecular mechanisms underlying AD make it difficult to predict when a patient will convert from prodromal stage to dementia. We hypothesize that metabolic alterations present at the level of the brain could be reflected at a systemic level in blood serum of patients, and that these alterations could be used as prognostic biomarkers. Methods: This pilot study proposes a serum investigation via nuclear magnetic resonance (NMR) spectroscopy in a consecutive series of AD patients including 57 patients affected by Alzheimer's disease at dementia stage (AD-dem) and 45 patients with mild cognitive impairment (MCI) due to AD (MCI-AD). As control group, we considered 31 subjects with mild cognitive impairment in whom AD and other neurodegenerative disorders were excluded (MCI). A panel of 26 metabolites and 112 lipoprotein-related parameters was quantified and the logistic LASSO regression algorithm was employed to identify the optimal combination of metabolites-lipoproteins and their ratios to discriminate the groups of interest. Results: In the training set, our model classified AD-dem and MCI with an accuracy of 81.7%. These results were reproduced in the validation set (accuracy 75.0%). Evolution of MCI-AD patients was evaluated over time. Patients who displayed a decrease in MMSE < 1.5 point per year were considered at lower progression rate: we obtained a division in 18 MCI-AD at lower progression rate (MCI-AD LR) and 27 at higher progression rate (MCI-AD HR). The model calculated using 4 metabolic features identified MCI-AD LR and MCI-AD HR with an accuracy of 73.3%. Conclusions: The identification of potential novel peripheral biomarkers of Alzheimer's disease, as proposed in this study, opens a new prospect for an innovative and minimally invasive method to identify AD in its very early stages. We proposed a novel approach able to sub-stratify MCI-AD patients identifying those associated with a faster rate of clinical progression. [ABSTRACT FROM AUTHOR]

In recent years, metal hydride research has become one of the driving forces of the high-pressure community, as it is believed to hold the key to superconductivity close to ambient temperature. While numerous novel metal hydride compounds have been reported and extensively investigated for their superconducting properties, little attention has been focused on the atomic and electronic states of hydrogen, the main ingredient in these novel compounds. Here, we present combined 1H- and 139La-NMR data on lanthanum superhydrides, LaHx, (x = 10.2 − 11.1), synthesized after laser heating at pressures above 160 GPa. Strikingly, we found hydrogen to be in a highly diffusive state at room temperature, with diffusion coefficients in the order of 10−6cm2s−1. We found that this diffusive state of hydrogen results in a dynamic de-hydrogenation of the sample over the course of several weeks, approaching a composition similar to its precursor materials. Quantitative measurements demonstrate that the synthesized superhydrides continuously decompose over time. Transport measurements underline this conclusion as superconducting critical temperatures were found to decrease significantly over time as well. This observation sheds new light on formerly unanswered questions on the long-term stability of metal superhydrides. The authors present nuclear magnetic resonance data on lanthanum superhydrides (LaHx) under high pressure. They find that the hydrogen is in a highly diffusive state which results in a dynamic de-hydrogenation of the sample on a time scale of weeks. [ABSTRACT FROM AUTHOR]

Background: The analysis of changes in subcellular water distribution during mushroom fruiting is essential for elucidating the movement of water molecules within subcellular compartments. However, prior research on mushrooms has predominantly concentrated on alterations in water status during drying and postharvest processes in the food processing sector. Knowledge regarding subcellular water compartments throughout mushroom growth and fruiting remains limited. In the present study, the dynamics of subcellular water status across various growth stages of Agaricus bisporus were investigated using LF-NMR relaxometry. Results: Three components were resolved from transverse relaxation curves, assigned to cell wall, cytoplasmic and vacuolar water, in both whole mushroom and mushroom tissues (stalk and Pileus). As fruiting body developed, the proton degree of freedom of three water fractions determined by T2 measurement all increased. The T2 values of three water fractions in stalk were higher than those in pileus during the first three stages, whereas they became lower compared to those in pileus from somewhere between the two stages of 2–3 and 3–4. Apparently different patterns of change in three water contents were observed, indicating the variations in water distribution at subcellular level. Furthermore, relative humidities caused obvious changes in water status. In addition, highly significant correlations were observed between T2 and textural parameters, indicating that the dynamics of water status exert a substantial influence on the formation of mushroom quality. Conclusions: A consistent increase in the transverse proton degree of freedom of three distinct water fractions, accompanied by markedly divergent patterns in the variations of the three water contents, was observed across different growth stages of fruiting bodies. Subsequently, highly significant correlations between T2 and textural parameters were established. This study would contribute to reveal macroscopic water transport within mushroom tissues and provide theoretical insights for optimizing high-quality mushroom cultivation. [ABSTRACT FROM AUTHOR]

Introduction: In the rapidly advancing field of 'omics research, there is an increasing demand for sophisticated bioinformatic tools to enable efficient and consistent data analysis. As biological datasets, particularly metabolomics, become larger and more complex, innovative strategies are essential for deciphering the intricate molecular and cellular networks. Methods: We introduce a pioneering analytical approach that combines Principal Component Analysis (PCA) with Graphical Lasso (GLASSO). This method is designed to reduce the dimensionality of large datasets while preserving significant variance. For the first time, we applied the PCA-GLASSO algorithm (i.e., MetaboLINK) to metabolomics data derived from Nuclear Magnetic Resonance (NMR) spectroscopy performed on neural cells at various developmental stages, from human embryonic stem cells to neurons. Results: The MetaboLINK analysis of longitudinal metabolomics data has revealed distinct pathways related to amino acids, lipids, and energy metabolism, uniquely associated with specific cell progenies. These findings suggest that different metabolic pathways play a critical role at different stages of cellular development, each contributing to diverse cellular functions. Discussion: Our study demonstrates the efficacy of the MetaboLINK approach in analyzing NMR-based longitudinal metabolomic datasets, highlighting key metabolic shifts during cellular transitions. We share the methodology and the code to advance general 'omics research, providing a powerful tool for dissecting large datasets in neurobiology and other fields. [ABSTRACT FROM AUTHOR]

Salen ligands (salen = N,N'-ethylenebis(salicylimine)) are well-known for their versatility and widespread utility in chelating metal complexes. However, installation of hydrogen-bonding units on the salen framework, particularly functional groups that require amine-based precursors such as (thio)ureas, is difficult to achieve without the use of protecting group strategies. In this report, we show that the phenylketone analog of salicyladehyde is a stable alternative that enables the facile installation of hydrogen bonding (thio)urea groups on the salen scaffold, thus imparting anion binding abilities to a metal salen complex. Synthesis of symmetric N-phenyl(thio)urea salen ligands functionalized at the 3,3'-position and an unsymmetric salen ligand with N-phenylurea at the 5-position was achieved. Subsequent metalation with nickel (II) acetate afforded the nickel(II) complexes that were investigated for their anion binding properties towards F-, Cl-, Br-, CH3COO-, and H2PO4 -. Solid-state structures of the nickel(II) complexes as well as the Cl- bound dimer of the symmetric urea complex were obtained. The unusual acidity of the (thio)urea groups is reflected in the pKa-dependent anion binding behavior of the nickel(II) complexes, as elucidated by 1H and 19F Nuclear Magnetic Resonance (NMR) spectroscopy and Diffusion Ordered Spectroscopy (DOSY) experiments. [ABSTRACT FROM AUTHOR]

Supramolecular interactions play an important role in molecular recognition. Cyclodextrins (CDs) are excellent hosts that are frequently utilized in the identification of chemical compounds. Proper modifications to CD can give it the ability to accurately recognize specific molecules. In this research, CD was modified with the allylimidazole moiety to generate a synergistic effect. Remarkably, the newly formed cation probe exhibits selective recognition of 1-adamantanecarboxylic acid from six guest molecules, which cannot be achieved by CD or allylimidazole alone. The recognition is evidenced by the retention of hydrogen-deuterium exchange (HDX) properties in the formed complexes and a change in the chemical shift of protons (H-4, H-5) in the allylimidazol backbone. Wavefunction analysis was employed to demonstrate that the mechanism of molecular recognition is the electrostatic interaction between host and guest molecules as well as the hydrogen bond formed by the guest molecule with the imidazole moiety H-2. This work reports an intramolecular synergistic strategy to specifically identify 1-adamantanecarboxylic acid, which could inspire probe design for various analysts. [ABSTRACT FROM AUTHOR]

The utilization of aliphatic diols as a substitute for epoxides in the reaction with CO2 to produce cyclic carbonates offers a cost-effective and less hazardous synthesis route. This approach aligns with green chemistry principles and presents new strategies to combat climate change. This study primarily focuses on the innovative application of an alkaline ionic liquid in conjunction with a Brønsted acid for the catalytic synthesis of cyclic carbonates from CO2 and aliphatic diols. Three alkaline ionic liquid catalysts [DBUH]PHY, [TBDH]PHY, and [DBUH]TBD were successfully synthesized using 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD), and phenol as precursors. Their chemical structures and thermal properties were systematically characterized using Fourier-transform infrared spectroscopy (FT-IR), proton nuclear magnetic resonance (1H-NMR), carbon nuclear magnetic resonance (13C-NMR), and thermogravimetric (TG) analysis. The catalytic performance of the three alkaline ionic liquids combined with various Brønsted acids (including sulfuric acid, phosphoric acid, and acetic acid) for the synthesis of ethylene carbonate (EC) from ethylene glycol (EG) and CO2 was investigated. The results demonstrated that the combination of [DBUH]PHY with sulfuric acid (H2SO4) exhibited the best synergetic catalytic effect. Subsequently, the process parameters were optimized to study the effects of reaction temperature, pressure, time, and catalyst loading on catalytic performance. Under optimized conditions, the catalytic efficiency of [DBUH]PHY and sulfuric acid in the synthesis of cyclic carbonates from different aliphatic diols, including ethylene glycol, propylene glycol (1,2- and 1,3-), and butanediol (1,4-), was explored. This study successfully achieved the activation of aliphatic diols and CO2 through cooperative catalysis of alkaline ionic liquids and Brønsted acids, providing an innovative catalytic system for research in this field. [ABSTRACT FROM AUTHOR]

This study introduces an innovative approach to automatically analyzing 1H nuclear magnetic resonance (NMR) data, integrating a quantum mechanical spectral analysis (QMSA) to enhance efficiency over manual data analysis in NMR. This proposed digital platform features a standardized quantitative NMR (qNMR) procedure, digital Reference Spectra within a spectral library, and a visualized interactive interface for streamlined, automated NMR data analysis. This digital platform significantly reduces the need for manual intervention and shows promise in using spectral fitting to compare the calculated spectrum derived from a digital Reference Spectrum with an experimental spectrum. The digital platform excels in processing data of both single chemical and mixture, delivering accurate results, and positioning it as an essential tool for automatic 1H qNMR analyses. Case studies highlight the digital platform's effectiveness, demonstrating its wide-ranging applicability. This shows that the proposed digital platform, based on a qNMR-based QMSA approach, offers reliable qualitative and quantitative analyses and paves the way for integrating digital reference standards into future compendial tests. [ABSTRACT FROM AUTHOR]

Group A Streptococcus (Strep A) is a human-exclusive bacterial pathogen killing annually more than 500,000 patients, and no current licensed vaccine exists. Strep A bacteria are highly diverse, but all produce an essential, abundant, and conserved surface carbohydrate, the Group A Carbohydrate, which contains a rhamnose polysaccharide (RhaPS) backbone. RhaPS is a validated universal vaccine candidate in a glycoconjugate prepared by chemical conjugation of the native carbohydrate to a carrier protein. We engineered the Group A Carbohydrate biosynthesis pathway to enable recombinant production using the industry standard route to couple RhaPS to selected carrier proteins within Escherichia coli cells. The structural integrity of the produced recombinant glycoconjugate vaccines was confirmed by Nuclear Magnetic Resonance (NMR) spectroscopy and mass spectrometry. Purified RhaPS glycoconjugates elicited carbohydrate-specific antibodies in mice and rabbits and bound to the surface of multiple Strep A strains of diverse M-types, confirming the recombinantly produced RhaPS glycoconjugates as valuable vaccine candidates. [ABSTRACT FROM AUTHOR]

The utilization of aliphatic diols as a substitute for epoxides in the reaction with CO2 to produce cyclic carbonates offers a cost-effective and less hazardous synthesis route. This approach aligns with green chemistry principles and presents new strategies to combat climate change. This study primarily focuses on the innovative application of an alkaline ionic liquid in conjunction with a Brønsted acid for the catalytic synthesis of cyclic carbonates from CO2 and aliphatic diols. Three alkaline ionic liquid catalysts [DBUH]PHY, [TBDH]PHY, and [DBUH]TBD were successfully synthesized using 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD), and phenol as precursors. Their chemical structures and thermal properties were systematically characterized using Fourier-transform infrared spectroscopy (FT-IR), proton nuclear magnetic resonance (1H-NMR), carbon nuclear magnetic resonance (13C-NMR), and thermogravimetric (TG) analysis. The catalytic performance of the three alkaline ionic liquids combined with various Brønsted acids (including sulfuric acid, phosphoric acid, and acetic acid) for the synthesis of ethylene carbonate (EC) from ethylene glycol (EG) and CO2 was investigated. The results demonstrated that the combination of [DBUH]PHY with sulfuric acid (H2SO4) exhibited the best synergetic catalytic effect. Subsequently, the process parameters were optimized to study the effects of reaction temperature, pressure, time, and catalyst loading on catalytic performance. Under optimized conditions, the catalytic efficiency of [DBUH]PHY and sulfuric acid in the synthesis of cyclic carbonates from different aliphatic diols, including ethylene glycol, propylene glycol (1,2- and 1,3-), and butanediol (1,4-), was explored. This study successfully achieved the activation of aliphatic diols and CO2 through cooperative catalysis of alkaline ionic liquids and Brønsted acids, providing an innovative catalytic system for research in this field. [ABSTRACT FROM AUTHOR]

The high sensitivity, high selectivity, real-time monitoring capability, non-destructiveness, and versatility of small molecule fluorescent probes make them indispensable and powerful tools in bioscience research. Self-assembling fluorescent probes are a novel type of material that spontaneously assemble fluorescent dyes with specific molecules into nanoscale structures. Compared with ordinary small molecule fluorescent probes, self-assembled fluorescent probes have higher stability, selectivity, sensitivity, and temporal stability in detection. In recent years, the incidence and mortality of cancer have increased year by year, which has brought great challenges to the safety of human life, and traditional diagnostic methods such as nuclear magnetic resonance, ultrasound diagnosis, and X-ray tomography are time-consuming and have low resolution. The boundary between normal tissue and cancer tissue cannot be accurately distinguished during surgical resection, resulting in the possibility of recurrence after surgery. Fluorescent probes can quickly and efficiently diagnose and label cancerous tumor cells, which is of great significance for cancer discovery and treatment. In this paper, we review the classification of self-assembled fluorescent probes (molecular self-assembled fluorescent probes, nanomaterial self-assembled fluorescent probes and biological macromolecule self-assembled fluorescent probes) that are used in identifying and imaging cancerous tumor tissues. Furthermore, we discuss the current problems faced by self-assembled fluorescent probes through the specific identification and monitoring of enzymes with abnormal contents, active substances and low pH in the tumor microenvironment, hoping to give readers more inspiration. [ABSTRACT FROM AUTHOR]

Background: Plant cell walls are made of a complex network of interacting polymers that play a critical role in plant development and responses to environmental changes. Thus, improving plant biomass and fitness requires the elucidation of the structural organization of plant cell walls in their native environment. The 13C-based multi-dimensional solid-state nuclear magnetic resonance (ssNMR) has been instrumental in revealing the structural information of plant cell walls through 2D and 3D correlation spectral analyses. However, the requirement of enriching plants with 13C limits the applicability of this method. To our knowledge, there is only a very limited set of methods currently available that achieve high levels of 13C-labeling of plant materials using 13CO2, and most of them require large amounts of 13CO2 in larger growth chambers. Results: In this study, a simplified protocol for 13C-labeling of plant materials is introduced that allows ca 60% labeling of the cell walls, as quantified by comparison with commercially labeled samples. This level of 13C-enrichment is sufficient for all conventional 2D and 3D correlation ssNMR experiments for detailed analysis of plant cell wall structure. The protocol is based on a convenient and easy setup to supply both 13C-labeled glucose and 13CO2 using a vacuum-desiccator. The protocol does not require large amounts of 13CO2. Conclusion: This study shows that our 13C-labeling of plant materials can make the accessibility to ssNMR technique easy and affordable. The derived high-resolution 2D and 3D correlation spectra are used to extract structural information of plant cell walls. This helps to better understand the influence of polysaccharide-polysaccharide interaction on plant performance and allows for a more precise parametrization of plant cell wall models. [ABSTRACT FROM AUTHOR]

Background: Xanthones are dubbed as putative lead-like molecules for cancer drug design and discovery. This study was aimed at the synthesis, characterization, and in silico target fishing of novel xanthone derivatives. Methods: The products of reactions of xanthydrol with urea, thiourea, and thiosemicarbazide reacted with α-haloketones to prepare the thiazolone compounds. Xanthydrol reacted sequentially with ethyl chloroacetate, hydrazine, carbon disulfide, and α-haloketones to prepare the dithiolane. The xanthydrol reacted with propargyl bromide and it submitted to click reaction with azide to prepare triazole ring. Results: Finally, four novel xanthones derivatives including (E)-2-(2-(9 H -xanthen-9-yl)hydrazono)-1,3-dithiolan-4-one (L3), 2-(2-(9 H -xanthen-9-yl)hydrazinyl)thiazol-5(4 H)-one (L5), 2-(9 H -xanthen-9-ylamino)thiazol-5(4H)-one (L7), and 4-((9 H -xanthen-9-yloxy)methyl)-1-(4-nitrophenyl)-1 H -1,2,3-triazole (L9) were synthesized and characterized using thin layer chromatography, Fourier-transform infrared spectroscopy, and nuclear magnetic resonance (1H and 13C). ADMET, Pfizer filter, adverse drug reaction, toxicity, antitarget interaction profiles, target fishing, kinase target screening, molecular docking validation, and protein and gene network analysis were computed for derivatives. Ligands obeyed Pfizer filter for drug-likeness, while all ligands were categorized as toxic chemicals. Major targets of all ligands were predicted to be kinases including Haspin, WEE2, and PIM3. Mitogen-activated protein kinase 1 was the hub gene of target kinase network of all derivatives. All the ligands were predicted to show hepatotoxic potentials, while L7 presented cardiac toxicity. Conclusion: Acute leukemic T-cells were one of the top predicted tumor cell lines for these ligands. The possible antileukemic effects of synthesized xanthone derivatives are potentially very interesting and warrant further studies. [ABSTRACT FROM AUTHOR]

The use of biomass feedstocks for producing high-value-added chemicals is gaining significant attention in the academic community. In this study, near-infrared carbon dots (NIR-CDs) with antimicrobial and bioimaging functions were prepared from Epigynum auritum branches and leaves using a novel green synthesis approach. The spectral properties of the synthesized NIR-CDs were characterized by ultraviolet–visible (UV-Vis) absorption and fluorescence spectroscopy. The crystal structures of the NIR-CDs were further characterized by high-resolution transmission electron microscopy (HR-TEM), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FT-IR), nuclear magnetic resonance (NMR), and X-ray diffraction (XRD). The NIR-CDs exhibited minimal toxicity, excellent biocompatibility, and high penetrability in both in vivo and in vitro environments, making them ideal luminescent probes for bioimaging applications. Moreover, the antimicrobial activity of NIR-CDs was tested against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli), showing significant bacterial growth inhibition. The antimicrobial effect is likely attributed to the NIR-CDs disrupting the cell membrane integrity, leading to the leakage of the intracellular contents. Therefore, NIR-CDs hold promise as fluorescent bioimaging probes and antimicrobial agents. [ABSTRACT FROM AUTHOR]

Non-ionic surfactants are an important solvent in the field of green chemistry with tremendous application potential. Understanding their phase properties in bulk or in confined environments is of high commercial value. In recent years, the combination of molecular dynamics (MD) simulations with multinuclear solid-state NMR spectroscopy and calorimetric techniques has evolved into the most powerful tool for their investigation. Showing recent examples from our groups, the present review demonstrates the power and versatility of this approach, which can handle both small model-surfactants like octanol and large technical surfactants like technical polyethylene glycol (PEG) mixtures and reveals otherwise unobtainable knowledge about their phase behavior and the underlying molecular arrangements. [ABSTRACT FROM AUTHOR]

Transitions seen in the electric properties of water-absorbable poly(2,5-benzimidazole) (ABPBI) films were confirmed by electric conductivity, dielectric constant, and time-domain nuclear magnetic resonance (NMR) measurements. The electric resistance of the films was measured at room temperature using a high-resistance meter, and the dielectric constant at room temperature was measured using an LCR meter in the frequency range of 90 Hz to 8 MHz. The water absorption ratio at equilibrium absorption for the films was 37%, which corresponded to a volume fraction of water of 0.33. The electric conductivity of the films without water absorption was ~1014 S·cm−1, and it increased to ~1010 S·cm−1 with increasing volume fraction, showing a percolation threshold at a volume fraction of 0.025, and remarkable transitions at volume fractions of 0.075 and 0.135. The dielectric constant of the films without water absorption was 3.4, and it increased to 8.1 with increasing volume fraction, showing a transition only at a volume fraction of 0.135. Above a volume fraction of 0.075, where a transition in conductivity was observed, there were two relaxation times at 18–31 μs and 20–93 μs, as determined from the time-domain NMR, and these relaxation times increased with increasing volume fraction. The longer relaxation time increased significantly at a volume fraction of 0.072, which was close to the volume fraction of the transition seen in conductivity. The relationship between the chain mobility of ABPBI and the deterioration in electric insulating properties is discussed. [ABSTRACT FROM AUTHOR]

BACKGROUND: The relationship between phosphorus (P) related enzymatic activity and organic P turnover remains unclear, particularly in the context of biochar application. Field experiments were conducted on Phaeozem and Luvisol soil types to investigate the effects of biochar application rates – 0 t ha−1 (CK), 22.5 t ha−1 (D1), 67.5 t ha−1 (D2), and 112.5 t ha−1 (D3) – on soil organic fractions using 31P nuclear magnetic resonance (NMR) spectroscopy and relevant phosphatase activity. RESULTS: The application of biochar increased the soil organic carbon (SOC), pyrophosphate (pyro), and orthophosphate (ortho) content, as well as the acid phosphomonoesterase (AcP), alkaline phosphomonoesterase (AlP), inorganic pyrophosphatase (IPP), and phosphodiesterase (PD) activities. Biochar application also increased soil organic P (OPa), the sum of inorganic P forms (IP), ortho, monoesters, and myo‐IHP contents, the pH value, AlP and PD activities in Phaeozem, but it significantly reduced diesters, polyphosphate (poly) contents, and IPP and AcP activities compared to those in Luvisol. Acid phosphomonoesterase and PD activities also showed an opposite trend in Luvisol. The structural equation model showed that the potential mechanism of organic P turnover in response to biochar application differed depending on the soil types, potentially influenced by P availability. CONCLUSION: Overall, the findings of this study enhance the comprehension of the variation of P fractions and their availability in the context of biochar application for agricultural production in northeastern China. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Background: In this study, hard candies were produced by using sucrose, glucose syrup and water. They were cooked at different temperatures, changing from 135 to 145 °C with an interval of 2.5 °C. They were stored at different storage temperatures, which were 25, 4, −18 and −80 °C. Hard candies placed at room temperature were stored for 2 months. In order to understand the crystallization characteristics of the hard candies, time domain (TD) proton nuclear magnetic resonance (1H‐NMR) parameters of longitudinal relaxation time (T1) and second moment (M2) measurements were conducted. Moisture contents of the hard candies were determined by Karl–Fischer titration. X‐ray diffraction experiments were also conducted as the complementary analysis. Results: Increasing cooking temperature increased the crystallinity and decreased the moisture content of the hard candies significantly (P ≤0.05). Furthermore, storage temperature and storage time had significant effects on the crystallinity of the hard candies (P ≤0.05). The results of T1 and M2 correlated with each other (r > 0.8, P ≤ 0.5) and both produced the highest value at the cooking temperature of 145 °C and storage temperature of 4 °C (P ≤ 0.05). The values of T1 and M2 were obtained as 245.9 ms and 13.0 × 10−8 Hz2, respectively, for the cooking temperature of 145 °C and storage temperature of 4 °C. Conclusion: This study demonstrated that the crystallinity of hard candies can be observed and examined by TD‐NMR relaxometry, as an alternative to commonly used methods. © 2024 The Author(s). Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Iisatin hybrids have emerged as effective weapons against diseases. In this context, chalcone tethered isatin-coumarin hybrid 3 was synthesized and used as a building block for the preparation of a new series of isatin-pyrazole, isatin-bridged dibenzo-diazonin and isatin-coumarin hybrids 4–10 by reaction with ammonium acetate or primary aromatic amines. The hybrids 4–10 were linked with bioactive linkers named ethene, furan, pyrrole or its derivatives. Through another reaction route, the polyfused pyrano-indoles 11–13 were synthesized by one pot reaction of isatin - coumarin hybrid 3 with some primary amines having electron donating substituents. The chemical structures of the synthesized compounds were evaluated by infrared, nuclear magnetic resonance, MS and elemental analyses. The synthesized compounds were screened for their antioxidant, anti-inflammatory and antimicrobial effects. The results revealed that all the compounds have high antioxidant activity and some of these compounds provide anti-inflammatory effects close to that of indomethacin. While the antimicrobial effects were studied against both Gram - positive and Gram-negative bacteria, greater activity for compounds 3 and 6 was observed against Gram-positive bacteria (B. Subtilis). While compounds 3, 4, 6, 9 and 10 were active against Gram-negative bacteria (E. coli). [ABSTRACT FROM AUTHOR]

[Display omitted] • Effective resource utilization of vinegar residue (VR). • Coproducing amino acid-rich xylooligosaccharides (XOS) and humic-like acid from VR. • Optimizing the reaction conditions for maximum XOS yield of 19.88 %. In order to address the issue of low amino acid retention in the production of xylooligosaccharides (XOS) through hydrothermal pretreatment at high temperatures, a novel approach combining low temperature acid hydrolysis and enzymatic hydrolysis was employed. This innovative method not only allows for the production of amino acid-rich XOS, but also yields a valuable byproduct known as humic-like acid (HLA) from vinegar residue (VR). Under the optimal pretreatment conditions (89 °C, 6 h, 1.2 % sulfuric acid), the yield of XOS was 19.88 %. Furthermore, the hydrolyzate extracted from the acid pretreated VR had a content of 2.65 g/L amino acids (corresponding to the retention rate of 82.0 %), and the HLA yield of the sample was 10.51 %. Comprehensive analyses, such as Fourier transform infrared spectroscopy, elemental analysis, total acidic functional group, and nuclear magnetic resonance were employed to examine the structure and composition of the produced HLA, indicating that it was similar to that of natural commercial humic acid (CHA) extracted from minerals. Through this innovative approach, the production of amino acid-rich XOS and HLA from VR offers a sustainable solution that not only addresses the issue of low amino acid retention but also maximizes the potential of VR as a valuable resource. [ABSTRACT FROM AUTHOR]

The modification of proteins and other biomolecules with the small protein ubiquitin has enthralled scientists from many disciplines for decades, creating a broad research field. Ubiquitin research is particularly rich in molecular and mechanistic understanding due to a plethora of (poly)ubiquitin structures alone and in complex with ubiquitin machineries. Furthermore, due to its favorable properties, ubiquitin serves as a model system for many biophysical and computational techniques. Here, we review the current knowledge of ubiquitin signals through a ubiquitin-centric, structural biology lens. We amalgamate the information from 240 structures in the Protein Data Bank (PDB), combined with single-molecule, molecular dynamics, and nuclear magnetic resonance (NMR) studies, to provide a comprehensive picture of ubiquitin and polyubiquitin structures and dynamics. We close with a discussion of the latest frontiers in ubiquitin research, namely the modification of ubiquitin by other post-translational modifications (PTMs) and the notion that ubiquitin is attached to biomolecules beyond proteins. Ubiquitin is a cellular modification that comes in many forms. In this review, Agrata and Komander analyze the 240 available PDB structures of ubiquitin and polyubiquitin, alongside ensemble and molecular dynamics models, to provide a detailed molecular picture of cellular ubiquitin modifications. [ABSTRACT FROM AUTHOR]

Background: Existing cardiovascular risk prediction models still have room for improvement in patients with type 2 diabetes who represent a high-risk population. This study evaluated whether adding metabolomic biomarkers could enhance the 10-year prediction of major adverse cardiovascular events (MACE) in these patients. Methods: Data from 10,257 to 1,039 patients with type 2 diabetes from the UK Biobank (UKB) and the German ESTHER cohort, respectively, were used for model derivation, internal and external validation. A total of 249 metabolites were measured with nuclear magnetic resonance (NMR) spectroscopy. Sex-specific LASSO regression with bootstrapping identified significant metabolites. The enhanced model's predictive performance was evaluated using Harrell's C-index. Results: Seven metabolomic biomarkers were selected by LASSO regression for enhanced MACE risk prediction (three for both sexes, three male- and one female-specific metabolite(s)). Especially albumin and the omega-3-fatty-acids-to-total-fatty-acids-percentage among males and lactate among females improved the C-index. In internal validation with 30% of the UKB, adding the selected metabolites to the SCORE2-Diabetes model increased the C-index statistically significantly (P = 0.037) from 0.660 to 0.678 in the total sample. In external validation with ESTHER, the C-index increase was higher (+ 0.043) and remained statistically significant (P = 0.011). Conclusions: Incorporating seven metabolomic biomarkers in the SCORE2-Diabetes model enhanced its ability to predict MACE in patients with type 2 diabetes. Given the latest cost reduction and standardization efforts, NMR metabolomics has the potential for translation into the clinical routine. [ABSTRACT FROM AUTHOR]

Previous studies in quantum information have recognized that specific types of noise can encode information in certain applications. However, the role of noise in quantum hypothesis testing, traditionally assumed to undermine performance, has not been thoroughly explored. Our study provides sufficient conditions for general noisy dynamics to surpass noiseless (unitary) dynamics within certain time interval. We then design and experimentally implement a noise-assisted quantum hypothesis testing protocol on ultralow-field nuclear magnetic resonance systems, which demonstrates that the success probability under certain noisy dynamics can indeed surpass the ceiling set by unitary evolution. Moreover, we show that in cases where noise initially hampers performance, strategic application of coherent controls on the system can transform those previously detrimental noises into advantageous ones. Our results, both theoretical and experimental, demonstrates the potential to leveraging noise in quantum hypothesis testing, which pushes the boundaries of quantum hypothesis testing and general quantum information processing. In quantum science, quantum hypothesis testing (QHT) is used to determine the model of a given quantum system, but normally the presence of inherent quantum noise hampers perfect hypothesis testing. The authors theoretically and experimentally explore the potential of leveraging noise in quantum hypothesis testing (QHT) to surpass the success probabilities achievable under noiseless dynamics. [ABSTRACT FROM AUTHOR]

A new and sustainable liquid organic hydrogen carrier, Lignin Jet Fuel-based Liquid Organic Hydrogen Carrier (LJF-HyC), has been discovered. This innovative LOHC is created from Lignin Jet Fuel (LJF) through dehydrogenation reactions. The process was carried out in situ using platinum nanoparticles supported on zeolite, resulting in a significant increase in aromatic carbon content. This increase indicates the successful formation of aromatic rings via C–H dissociation. In-situ Nuclear Magnetic Resonance (NMR) and gas chromatographic analyses revealed the formation of unsaturated and partially unsaturated compounds, including alkylbenzenes, tetralins, naphthalenes with double bond equivalence of 4–8, from six apparent reaction pathways, four of which can be major. The original LJF, consisting primarily of mono-, di-, and tricyclohexylalkanes (96 wt%), was converted to dehydrogenated products, constituting approximately 18.5 wt% of the LJF composition. These findings pave the way for developing sustainable hydrogen carriers derived from sustainable aviation fuels. [Display omitted] • A Lignin Jet Fuel-Based Liquid Organic Hydrogen Carrier (LJF-HyC) was developed. • In-situ dehydrogenation with Pt/zeolite increased aromatic carbon formation. • LJF-HyC contents unsaturated species such as alkylbenzenes, tetralins, naphthalenes. • LJF-HyC constituted approximately 18.5 wt% of the dehydrogenated LJF composition. [ABSTRACT FROM AUTHOR]

Despite the advancements in hemostatic agents, global mortality rate due to bleeding remains a significant concern. In this study, to mitigate the drawbacks associated with traditional hemostatic agents, we harnessed a combination of gelatin (G), oxidized regenerated cellulose, and sodium tripolyphosphate (NaTPP). Leveraging nanotechnology further enhanced the hemostatic efficacy. To exploit synergies and optimize surface modification, four composites were formulated: G-NaORC, G-NaORC-NaTPP, aminated gelatin (AG)-NaORC, and AG-NaORC-NaTPP. Nuclear magnetic resonance spectra (1H- and 13C-NMR) and Fourier transform infrared spectrometer analyzes were employed to confirm the accuracy of gelatin amination and to establish chemical and physical cross-linking groups. Then, using electrospinning, nanofibers were prepared from each group to ensure the beneficial effects of synergy and surface modification. The resultant sponges and nanofibrous mats were then characterized morphologically using SEM. Degradation, hydrophilicity, swelling ratio, and hemolytic properties of the hemostatic constructs were assessed. The hemostatic rate and cytocompatibility of the samples were evaluated using PT/PTT tests and MTT assays, respectively. Our results showed that the AG-NaORC-NaTPP nanofiber mat endowed the best hemostatic capabilities by reducing the coagulation time by about 30%. The resulting formulation addresses critical aspects in pursuing effective hemostatic solutions. [ABSTRACT FROM AUTHOR]

A comprehensive framework for designing a micro-nuclear magnetic resonance (NMR) front-end is presented. Key radio frequency (RF) engineering principles are established to enable efficient excitation and detection of NMR signals. This foundation aims to guide the optimal design of novel handheld NMR devices operating with magnetic fields ( B 0 ) below 0.5 Tesla and RF frequencies under 30 MHz. To address the complexities of signal-to-noise ratio optimization in this regime, a specialized metric called the coil performance factor (CPF) is introduced, emphasizing the role of coil design. Through systematic optimization under realistic constraints, an optimal coil configuration maximizing the CPF is identified. This design, with three turns, a coil width of 0.22 mm, and a coil spacing of 0.15 mm, achieves an optimal balance between magnetic field strength, homogeneity, and noise. This work serves as a valuable resource for engineers developing optimized coil designs and RF solutions for handheld NMR devices, providing clear explanations of essential concepts and a practical design methodology. [ABSTRACT FROM AUTHOR]

Nuclear magnetic resonance (NMR) and high-pressure mercury injection (HPMI) have been widely used as common characterization methods of pore-throat. It is generally believed that there is a power function relationship between transverse relaxation time (T2) and pore-throat radius (r), but the segmentation process of the pore-throat interval is subjective, which affects the conversion accuracy. In this paper, ordered clustering is used to improve the existing segmentation method of the pore-throat interval, eliminate the subjectivity in the segmentation process, and obtain a more accurate distribution curve of the pore-throat. For the three kinds of cores with ordinary-low permeability (K > 1 mD), ultra-low permeability (0.1 mD < K < 1 mD), and super-low permeability (K < 0.1 mD), the pore-throat distribution curves of the cores were obtained by using the improved T2 conversion method. Then, the oil and gas two-phase displacement experiment was carried out to investigate the degree of recovery and cumulative gas–oil ratio changes during the displacement process. Finally, the converted T2 spectrum was used to quantify the utilization of different pore sizes. The improved T2 conversion method not only has better accuracy but also is not limited by the pore-throat distribution types (such as unimodal, bimodal, and multi-modal, etc.) and is suitable for any core with measured HPMI pore-throat distribution and an NMR T2 spectrum. Combined with the results of core displacement and the degree of pore-throat utilization, it is found that the potential of miscible flooding to improve the recovery degree is in the order of ordinary-low permeability core (18–22%), ultra-low permeability core (25–29%), and super-low permeability core (8–12%). The utilization degree of immiscible flooding to the <10 nm pore-throat is low (up to 35%), while miscible flooding can effectively use the <3.7 nm pore-throat (up to 73%). The development effect of supercritical CO2 flooding on K < 0.1 mD reservoirs is not good, the seepage resistance of CO2 is large, the miscible flooding makes it difficult to improve the recovery degree, and the utilization effect of pore-throat is poor. [ABSTRACT FROM AUTHOR]

In deep brine oil and gas injection–production operations, the combined long-term effects of brine and carbon dioxide on rock mechanical properties are not clear. In order to solve this problem, the influence of long-term salt–CO2 environment on the mechanical properties of sandstone is discussed. The mechanism of interaction evolution and fracture propagation was studied in detail by NMR, the triaxial compression test and a CT scan. The results show that the triaxial compressive strength and mass of sandstone decrease first and then increase with the prolonging of soaking time. The proportion of micropores first decreased and then increased, while the proportion of medium and large pores first increased and then decreased. The pores obtained by Avizo's segmentation of the threshold value of CT sections first increased and then decreased, and the fractal dimensions obtained first increased and then decreased. In particular, the calcium ions in the immersion solution increased first and then decreased. The reaction rate was obtained and verified according to the changes in calcium carbonate mass and calcium ion mineralization at different times. The failure mode of the sample gradually changed from /-shaped failure to V-shaped composite failure, then to local /-shaped failure, and finally to X-shaped composite failure. On this basis, the process of sandstone was divided into the dissolution stage, precipitation stage and secondary dissolution stage, and the rock microstructure change model under a salt–CO2 environment was established. The mechanics, temperature, chemical interaction mechanism and fracture propagation mechanism of sandstone under a salt–CO2 environment are discussed. [ABSTRACT FROM AUTHOR]

The present investigation was carried out to characterise bioactive components from G. senegalensis by using Fourier-transform infra-red (FT-IR) spectroscopy, 1H-nuclear magnetic resonance spectroscopy, and gas chromatography-mass spectrometry (GC-MS). The FTIR analysis confirmed the presence of > CH2, -CH3, C = C-C, C-H, C-F, C = C, -C = N-, C-C = N-, and -OH functional groups. The 1H-NMR spectrum revealed the presence of structures of four bioactive compounds i.e. tetratetracontana derivative, β-carotene, amyrin, and terpineol. GC-MS revealed the presence of different types of high and low molecular weight chemical entities with varying quantities including volatile and essential oil, monoterpenoid, tetraterpenoid, carotenoid, terpenoid, triterpenes, and nortriterpenes. From the results, it could be concluded that G. senegalensis contains various bioactive compounds of biological and pharmacological importance. Overall, this study will provide insight into the characterisation and development of drugs from medicinal plants. [ABSTRACT FROM AUTHOR]

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Polymeric materials are highlighted in the global market due to their low cost, excellent properties, and diversity of applications, such as food packaging, which in addition to protecting packaged foods also promotes control and conservation against contaminants. Thus, the objective of this research is to investigate the effects of adding silica nanoparticles and cellulose nanofibers, alone and together, on the properties of poly(butylene adipate‐co‐terephthalate), aiming for application in food packaging. For this purpose, PBAT and the nanofillers were initially mixed in a rheometer to produce masterbatches, and, then, to be processed by a single screw extruder to generate the nanocomposites. The nanocomposites are analyzed by scanning electron microscopy, x‐ray diffraction, thermogravimetric analysis, differential scanning calorimetry, nuclear magnetic resonance, tensile testing, water contact angle, and microbial permeability. In low concentrations, it is observed that the system tends to be less heterogeneous. Nanoparticles do not interfere with thermal stability and present a barrier to microorganisms. Interestingly, in the two conditions studied, polymers with cellulose nanofibers or silica nanoparticles have filtering capacity, being effective as physical barriers to the growth of microorganisms within 60 days. However, the effect on mechanical properties is small, being more pronounced with the use of cellulose nanofibers. [ABSTRACT FROM AUTHOR]

During the course of our ongoing study of the diversity of Thai fungi and their secondary metabolites, numerous specimens within the Hypoxylaceae have been characterised by traditional morphology, chemotaxonomy using ultra-high-performance liquid chromatography coupled to diode array detection and ion mobility tandem mass spectrometry (UHPLC-DAD-IM-MS/MS), and molecular phylogenetic analyses. MS/MS-based analysis of the major stromatal metabolites of a newly identified taxon, Hypoxylon luteogranulatum, indicated the production of distinct compounds compared to the azaphilone and binaphthalene pigments commonly found in the Hypoxylaceae, aside from the presence of the chemotaxonomic marker binaphthalene tetrol (BNT). Further analysis suggested that one of the major metabolites had the molecular formula C13H13NO3, identical to hypoxyvermelhotin A, a yellow pigment so far exclusively found in Hypoxylon lechatii. Its identity was confirmed after purification by preparative high-performance liquid chromatography with nuclear magnetic resonance (NMR) data, and genome analysis of H. lechatii revealed the presence of different hybrid polyketide synthases-non-ribosomal peptide synthetases (PKS-NRPS) hybrid clusters. Despite chemotaxonomic similarities with H. lechatii, we propose a new species, which is morphologically distinct from H. lechatii. Our molecular phylogenetic study provides substantial evidence distinguishing H. luteogranulatum clearly from H. lechatii and allied members within the Hypoxylaceae. Additionally, future studies are needed to better understand the ecological behaviour of H. luteogranulatum and identify the ecological role of the vermelhotin-like molecules within this putative interaction. [ABSTRACT FROM AUTHOR]

Incorporating inorganic particles is a common approach to preparing polymeric materials with desirable physical properties and processability. However, this often results in increased brittleness, necessitating methods to improve melt strength and toughness. In this study, in situ polymerization was employed to functionalize silica nanoparticles with the silane coupling agent (3‐aminopropyl) triethoxysilane (APTES) as a core. A flexible chain segment, poly(butylene itaconate) (PBI), was then introduced as a "rubbery" intermediate layer, resulting in a core‐shell structure of poly(L‐lactic‐co‐butanediol itaconate) nano‐silica copolymer films (PLBISiO2) with both branched and "rubbery" structures. Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (NMR) confirmed the formation of macromolecular chains, with the molecular weight (Mn) of PLBI increasing from 59,638 to 74,306 g/mol. This significant increase supports the "rubbery" core‐shell structure. When 0.5% SiO2 was added, the T5% of the film increased by 40°C, significantly improving thermal stability. Additionally, the elongation at break increased to 265.7%, while retaining the original tensile strength. Dynamic rheology experiments further confirmed the generation of branched or "rubbery" core‐shell structures, and a doubling of gas barrier properties was observed with increased silica nanoparticles, suggesting potential applications in food packaging or biopharmaceuticals. Highlights: Nanocomposites with core‐shell structure and improved mechanical properties.Dynamic rheology experiments confirmed the formation of the core‐shell structure.Significantly improved gas barrier properties due to core‐shell structure. [ABSTRACT FROM AUTHOR]

Background: This study employed melanin synthesized by Aspergillus flavus and Aspergillus carbonarius to inhibit the production of mycotoxins and bioremediation of heavy metals (HMs). Methods: First, twenty fungal isolates were obtained from soil samples, and were evaluated to produce melanin. The melanin of the most potent producers has undergone several confirmatory experiments, including, Dihydroxyphenylalanine (DOPA)-inhibitor-kojic acid pathway detection, High-performance liquid chromatography (HPLC), Fourier-transform infrared (FTIR) and Nuclear magnetic resonance (NMR). Additionally, the melanin production culture conditions were optimized. The antioxidant activity of melanin was detected with 1,1-Diphenyl-2-picrylhydrazyl (DPPH). HPLC was used to measure the mycotoxins produced in culture media supplemented with melanin. Molecular docking study investigated molecular interactions between melanin and mycotoxins through in silico approaches. FTIR and Energy-dispersive X-ray spectroscopy (EDX) were utilized to determine the percentage of melanin-chelated HMs, and an atomic absorption spectrophotometer (AAS) was used to detect HMs removal efficiency. Results: The melanin-enriched medium (0.3% and 0.4%) exhibited complete inhibition of aflatoxin B1 (AF-B1) by A. flavus and ochratoxin A (OTA) by A. carbonarius, respectively. Furthermore, melanin showed effective HM removal efficiency, increasing with melanin concentration. The removal efficiency of Cd+2 and Cr+6 by 1 mg/mL melanin was 49% and 63%, respectively. When the concentration of melanin was increased to 15 mg/mL, the removal efficiency of Cd+2 and Cr+2 increased to 60% and 77%, respectively. Conclusion: The study exhibited a natural approach for melanin production, using melanin as a heavy metal-chelating agent and capability to inhibit the production of aflatoxin B1 and ochratoxin A. Further, the study provides significant evidence regarding the bioremediation pipeline, for melanin production through biotechnological processes by filamentous fungi. [ABSTRACT FROM AUTHOR]

Metallic strontium titanate (SrTiO3) is known to have both normal-state and superconducting properties that strongly vary over a wide range of charge carrier densities, but the complex interplay between lattice and electronic degrees of freedom has hindered the development of a clear qualitative description of the observed behavior. A major challenge is to understand how the charge carriers themselves evolve with doping and temperature, with possible polaronic effects and evidence of an effective mass that strongly increases with temperature. Here we use 47,49Ti nuclear magnetic resonance (NMR) to perform a comprehensive study of the electronic spin susceptibility in the metallic state of strontium titanate across the doping-temperature phase diagram. We find a temperature-dependent Knight shift that can be quantitatively understood within a nondegenerate Fermi gas model that fully takes into account the complex band structure of SrTiO3. Our data are consistent with a temperature-independent effective mass, and we show that the behavior of the spin susceptibility is universal in a wide range of temperatures and carrier concentrations. These results provide a microscopic foundation for the understanding of the properties of the unconventional low-density metallic state in strontium titanate and related materials. [ABSTRACT FROM AUTHOR]

In this paper, we report various polyurethane nanocomposites of single‐walled carbon nanotubes using blocking–deblocking reactions. Thus, the synthesis was carried out using blocked isocyanates where, at deblocking temperature, isocyanates regenerated and reacted with polyol (PEG‐400) and single‐walled carbon nanotubes (SWCNTs) to form polyurethane nanocomposites. For example, at 185°C, regenerated (deblocked) hexamethylene diisocyanates was reacted with polyethylene glycol‐400 and SWCNT to form polyurethane nanocomposites. Similarly, at 238°C, regenerated (deblocked) toluene diisocyanates was reacted with polyethylene glycol‐400 and SWCNT to form polyurethane nanocomposites. The characterization of synthesized polyurethane nanocomposites has been done by Fourier transform infrared spectroscopy, nuclear magnetic resonance, thermogravimetric analysis, differential scanning calorimetry, field emission scanning electron microscopy, High resolution transmission electron microscopy and contact angle measurement. [ABSTRACT FROM AUTHOR]

Bio‐based plastics have received much attraction because they are an alternative to petroleum‐based plastics in recent years. Among them, aliphatic polyesters have garnered the most attention due to their excellent properties. Polyester is primarily synthesized through ring opening polymerization of monomer, and the catalysts used are mostly synthesized through "click" reaction in the laboratory, which exhibits inferior activity and little commercial value. Herein, a facile approach was developed for the synthesis of high molecular‐weight cyclic aliphatic polyesters, specifically poly(valerolactone‐co‐caprolactone) with varying compositions. This involved the ring‐opening copolymerization of ε‐caprolactone (ε‐CL) and δ‐valerolactone (δ‐VL) in the absence of an initiator with commercial hydrogen bond donor triclorocarban and an organic base. The structure and properties of the prepared cyclic polyester were investigated using GPC, 13C NMR, 1H NMR, MALDI‐TOF mass spectrometry, TOF‐SIMS mass spectrometry, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and X‐ray diffraction (XRD) techniques. The results show that the molecular weight of cyclic polyester can rapidly exceed 40 kDa, with a PDI of approximately 1.10. In comparison to linear polyester, it has a higher melting point and superior thermodynamic properties, thus presenting greater application potential. Finally, based on nuclear magnetic resonance titration, the potential catalytic processes and mechanisms of bimolecular systems on monomers in different environments were discussed. This study not only offers new insights into the structure and properties of cyclic polyesters, but also presents novel bimolecular catalytic systems using commercial urea hydrogen bond donors for the synthesis of cyclic polymer polyesters. [ABSTRACT FROM AUTHOR]

Four new triphenylphosphine-derived cage ligands were modularly synthesized via dynamic imine chemistry (DIC), and their absolute structures were characterized by single crystal X-ray diffraction (SXRD), nuclear magnetic resonance (NMR) and high resolution mass spectroscopy (HRMS). In contrast to smallmolecule analogues, cage ligands demonstrate superior activity and selectivity. The Rh/Cage-L2 catalyst exhibits remarkable performance with an aldehyde selectivity of 89%, accompanied by a TOF value of 2665 h−1 and an l/b ratio of 2.60, thereby showcasing leading activity, chemical selectivity, and regioselectivity in the realm of homogeneous catalysts that rely on triphenylphosphine ligands. The reason for the formation of a higher l/b ratio, with a 3.84 kJ mol−1 difference in the energy of the rate-determining step, has been explained through density functional theory (DFT) calculations. In addition, a Janus-type PPh3-Au complex has been discovered during the study of the coordination of cage ligands, offering partial corroboration for the single coordination mechanism of these cage ligands. The large steric hindrance effect of cage ligands is believed to play a pivotal role in the hydroformylation reaction. This work highlights the potential application of cage ligands and inspires future efforts in the search of highly selective and efficient organometallic catalysts. [ABSTRACT FROM AUTHOR]

Gem‐diols are defined as organic molecules carrying two hydroxyl groups at the same carbon atom, which is the result of the nucleophilic addition of water to a carbonyl group. In this work, the generation of the hydrated or hemiacetal forms using pyridine‐ and imidazole‐carboxaldehyde isomers in different chemical environments was studied by Nuclear Magnetic Resonance (NMR) recorded in different media and combined with theoretical calculations. The change in the position of aldehyde group in either the pyridine or the imidazole ring had a clear effect in the course of the hydration/hemiacetal generation reaction, which was favored in protic solvents mainly in the presence of methanol. For pyridinecarboxaldehydes, the acidity/basicity degree of the reaction medium influenced not only the generation of the gem‐diol or hemiacetal forms but also the oxidation to the corresponding carboxylic acid. However, imidazolecarboxaldehyde was found to be less reactive to the nucleophilic addition of water and methanol than the other compounds in all the environments evaluated. Furthermore, both the gem‐diol/hemiacetal generation and the Cannizzaro reaction products were studied in alkaline medium. [ABSTRACT FROM AUTHOR]

The glass optical basicity (Λ) is an adequate way of representing a glass composition that has been successfully applied for glasses made under ambient pressure conditions. However, we do not know if the proposed calculation based on the glass structure and the proposed measurement involving the determination of glass refractive index can apply to glasses made under high‐pressure conditions. We studied several aluminoborosilicate glass compositions synthesized under high‐pressure conditions up to 3 GPa and 1250°C. Recovered glasses were characterized to determine the refractive index (nD) and the density (ρ). The glass structure was determined using 11B and 27Al nuclear magnetic resonance. Increasing pressure up to 3 GPa increases nD and ρ for the studied glasses. Change in the glass structure is consistent with previous studies showing an increase in Al coordination, especially for Ca‐bearing glass composition; and an increase in the proportion of BO4 species. The glass optical basicity decreases with increasing pressure. From the structural changes, Λ decreases by ∼2% from ambient to 1 GPa in pressure for the investigated glass compositions. [ABSTRACT FROM AUTHOR]

In this study, we prepared diltiazem (DTZ)‐imprinted biomaterials for TDDS using chitosan, PVA, plasticizers, and sulfosuccinic acid. DTZ and the prepared biomaterials were characterized using field emission scanning electron microscopy, Fourier transform infrared, and 1H nuclear magnetic resonance. DTZ recognition properties were confirmed by the binding isotherm, Scatchard plot analysis, the adsorption of materials with structures similar to DTZ, selectivity factor (α), and the imprinting‐induced promotion of binding (IPB). Results revealed that adsorbed amount (Q) of DTZ‐imprinted biomaterials was 1.63–2.53 times higher than that of non‐imprinted biomaterials. In addition, it could be verified that DTZ‐imprinted biomaterials have a binding site for DTZ according to Scatchard plot analysis. Furthermore, the results of α and IPB indicated that the recognition capacity of the prepared DTZ‐imprinted biomaterials is superior to that non‐imprinted biomaterials. DTZ release properties were evaluated under various pH buffers and artificial skin. Results indicated that the DTZ release in buffers at low pH was faster than that in buffers at high pH. The DTZ release using artificial skin was continuous over 20 days. Furthermore, the DTZ release profile in the buffer followed the pseudo‐Fickian diffusion mechanism, whereas the profile in the artificial skin test followed a non‐Fickian diffusion mechanism. [ABSTRACT FROM AUTHOR]

Hydrazide-substituted phthalonitrile resin (1e) has been synthesized via nucleophilic substitution reaction of hydrazide-substituted bisphenol (1d) with 4-nitrophthalonitrile to introduce a flexible linking group between rings for low-melting material. The resin was molecularly designed with two flexible hinges of hydrazide functionality with an arm and a low melting point resin system. The resin monomer in Differential scanning calorimetry (DSC) analysis, instead of showing a low melting point, showed a relatively high melting peak (Tm) at 266 °C, due to the formation of a more stable enol form on account of an extended conjugation, which was confirmed by Nuclear Magnetic Resonance (NMR), Fourier Transform Infrared (FTIR), and Ultraviolet (UV) spectra. The monomer was assessed for its thermal, rheological, and curing characteristics. The DSC analysis of uncured 1e showed the onset of curing (Tons) at 269 °C along with curing window of 69 °C. The processing window was found to be ~40 °C by rheological tests. The enthalpy of curing for 1e was found to be 151.5 Jg−1. Thermogravimetric analysis (TGA) of the fully cured polymer (1f) revealed the onset of thermal degradation (Tdo) of 450 °C along with a char yield of 66 wt.% at 800 °C in N2 atmosphere. In air atmosphere multistep degradation was obtained and nil ash yield was found at 600 °C. The limiting oxygen index (LOI) value of the cured polymer (1f) was found to be ̴ 43.9 (estimated by Krevelen's equation). [ABSTRACT FROM AUTHOR]

Methane adsorption/desorption and permeability measurements are critical for evaluating reserves and production potential in coalbed methane (CBM) extraction. The varying temperature and stress in CBM wells have an impact on these characteristics. To understand these effects, take the Wenjiaba mining area and the Qinglong mining area in Guizhou, China, as the research objects, which are called WJB and QL for short. Characterizing the coal's surface area and pore structure using low-field nuclear magnetic resonance and low-temperature nitrogen adsorption is essential for methane flow and storage. The coal's adsorptive capacity under in situ conditions was revealed by isothermal methane adsorption tests conducted at pressures ranging from 0 to 18 MPa at different temperatures. Triaxial stress-controlled adsorption experiments simulated the impact of effective stress on methane adsorption. Stress-permeability tests evaluated the stress sensitivity and its effect on the coal's methane transmission ability, a key factor in CBM well producibility. The results showed that increased temperature reduced adsorption capacity for WJB and QL coals by 14.2% and 16.3%, respectively, while desorption rates and diffusion coefficients increased, suggesting that higher temperatures enhance desorption and diffusion. However, higher coal ranks can hinder desorption. Effective stress application led to over a 90% decrease in both adsorption capacity and permeability, emphasizing the need for stress management in CBM extraction. These insights provide a theoretical framework for the interplay between coal's pore structure, adsorption/desorption properties, and permeability under different stress and temperature conditions, guiding the optimization of CBM extraction strategies for efficient and sustainable methane recovery. [ABSTRACT FROM AUTHOR]

China possesses widely distributed low-permeability coal seams of various ranks, where differences in coal rank determine fracture mode selection and optimization of fracturing effects. This study investigates the response of low-rank lignite and high-rank anthracite to liquid nitrogen freeze–thaw. Using nuclear magnetic resonance technology, we examined T2 relaxation curves, porosity, and pore throat changes during freeze–thaw processes, focusing on unfrozen water from a microscopic perspective. Experimental results indicate that lignite exhibits significantly higher T2 relaxation amplitudes compared to anthracite, with a predominance of adsorption pores. Lignite shows a more pronounced response to freeze–thaw cycles, resulting in increases of 0.9% in cumulative porosity and 0.9% in pore throat count for lignite, while anthracite shows increases of 0.1% and 0.13%, respectively. The average aperture of flow pores increased by 45.2% and 49.4%. Upon returning to room temperature, lignite shows a two-stage increase in porosity loss rate after initial fluctuations, while anthracite exhibits a slightly fluctuating trend. Both lignite and anthracite demonstrate a lag effect in unfrozen water during freeze–thaw processes, with maximum lag percentages at −5 °C and 5 °C recorded as 51.07% and 67.75%, respectively. The primary factors contributing to the unfrozen water lag effect are the supercooling effect during freezing and changes in pore ice melting points due to water-ice phase transitions. The rapid temperature differential from low-temperature liquid nitrogen triggers uneven thermal stress within the coal body and freeze expansion, optimizing coal pore structure and enhancing connectivity and permeability. [ABSTRACT FROM AUTHOR]

Six new triterpenoids, heritieras C–H (1–6), along with thirteen known triterpenoids (7–19), were isolated from the leaves of Heritiera littoralis. Their structures were identified by spectroscopic analysis, including 1D and 2D nuclear magnetic resonance (NMR), high-resolution electrospray ionization mass spectrometry (HRESIMS), and by comparison with the literature. Anti-inflammatory activity of the isolates was evaluated using the lipopolysaccharide (LPS) stimulated RAW 264.7 cell model. Among the isolated triterpenoid, compounds 1, 12, 16, 17, and 18 demonstrated inhibitory activity against nitric oxide (NO) release, in which compound 18 exhibited the best activity with an IC50 value of 18.13 μM. The potential anti-inflammatory mechanism was investigated using molecular docking. The triterpenoids from H. littoralis could be served as potential candidates for the development of new anti-inflammatory agents. [ABSTRACT FROM AUTHOR]

Coronary heart disease (CHD) is the leading cause of morbidity and mortality worldwide despite significant improvements in diagnostic modalities. Emerging evidence suggests that erythrocytes, or red blood cells (RBCs), are one of the most important contributors to the events implicated in atherosclerosis, although the molecular mechanisms behind it are under investigation. We used NMR-based lipidomic technology to investigate the RBC lipidome in patients with CHD compared to those with normal coronary arteries (NCAs), all angiographically documented, and its correlation with coronary artery stenosis. Targeted and untargeted lipidomic analysis revealed that CHD patients presented significant lipid alterations in the RBC membrane, characterized by higher cholesterol, sphingolipids, saturated and monounsaturated fatty acids, lower phospholipids (glycerophospholipids and ether glycerolipids), and unsaturated and polyunsaturated fatty acids. These aberrations gradually distinguish the three subgroups of patients with mild, moderate, and severe coronary stenosis, potentially indicating their non-negligible involvement in the onset and progression of atherosclerosis. The comprehensive analysis of RBC-membrane-derived lipids with omics approaches could unravel specific lipid abnormalities taking place at the silent subclinical stage of atherosclerosis and could have the potential to identify patients with subtle, but still proatherogenic, abnormalities that may confer a higher risk for the development of CHD. [ABSTRACT FROM AUTHOR]

This study introduces a novel water-insoluble dispersant for coal water slurry (CWS), namely, a poly(sodium styrene sulfonate)-grafted SiO2 nanoparticle (SiO2-g-PSSNa). SiO2-g-PSSNa was synthesized by combining the surface acylation reaction with surface-initiated atom transfer radical polymerization (SI-ATRP). Fourier transform infrared spectrometry (FTIR), X-ray photoelectron spectroscopy (XPS), energy dispersive spectrometer (EDS), nuclear magnetic resonance spectroscopy (NMR) and thermogravimetric analysis (TGA) verified that SiO2-g-PSSNa with the desired structure was successfully obtained. Afterwards, the performance of SiO2-g-PSSNa as a dispersant in CWS preparation was evaluated. The results indicated that the optimal dosage of SiO2-g-PSSNa was 0.3%. Compared to the famous commercial products, PSSNa and lignosulfonate (LS), SiO2-g-PSSNa exhibits improved viscosity reduction performance. When SiO2-g-PSSNa was used as the dispersant, the maximum coal loading of CWS was 64.2%, which was higher than LS (63.4%) and PSSNa (63.9%). All CWSs obtained in this study were pseudoplastic fluids and more consistent with the Herschel–Bulkley rheological model. The turbiscan stability index (TSI) of CWS prepared with SiO2-g-PSSNa was 0.05, which was significantly lower than CWSs obtained from PSSNa (0.30) and LS (0.36). Therefore, SiO2-g-PSSNa also exhibits excellent stability performance. This result was confirmed by rod penetration tests. The underlying mechanism was also clarified by various measurements, such as contact angle, zeta potential, EDS and low-field nuclear magnetic resonance spectra (low-field NMR). The results reveal that SiO2-g-PSSNa can adsorbed onto the coal surface. SiO2-g-PSSNa possesses a special branched structure, which bears a higher charge density as compared to linear ones with approximate chemical composition. As a result, coal particles adsorbed with SiO2-g-PSSNa exhibit more electronegativity. With the enhancement of the electrostatic repulsive between coal particles, the apparent viscosity was lowered and the static stability was improved. This study demonstrated that solubility in water is not an essential factor in engineering the dispersant. Densely charged groups are probably more important. [ABSTRACT FROM AUTHOR]