Search

Thiolate containing mercury(II) complexes of the general formula [Hg(SR) n] 2−n have been of great interest since the toxicity of mercury was recognized. 199Hg nuclear magnetic resonance spectroscopy (NMR) is a powerful tool for characterization of mercury complexes. In this work, the Hg shielding constants in a series of [Hg(SR) n] 2−n complexes are therefore investigated computationally with particular emphasis on their geometry dependence. Geometry optimizations and NMR chemical shift calculations are performed at the density functional theory (DFT) level with both the zeroth‐order regular approximation (ZORA) and four‐component relativistic methods. The four exchange‐correlation (XC) functionals PBE0, PBE, B3LYP, and BLYP are used in combination with either Dyall's Gaussian‐type (GTO) or Slater‐type orbitals (STOs) basis sets. Comparing ZORA and four‐component calculations, one observes that the calculated shielding constants for a given molecular geometry have a constant difference of ∼1070 ppm. This confirms that ZORA is an acceptable relativistic method to compute NMR chemical shifts. The combinations of four‐component/PBE0/v3z and ZORA/PBE0/QZ4P are applied to explore the geometry dependence of the isotropic shielding. For a given coordination number, the distance between mercury and sulfur is the key factor affecting the shielding constant, while changes in bond and dihedral angles and even different side groups have relatively little impact. [ABSTRACT FROM AUTHOR]

Both experimental and clinical liver fibrosis leave a metabolic footprint that can be uncovered and defined using metabolomic approaches. Metabolomics combines pattern recognition algorithms with analytical chemistry, in particular, 1H and 13C nuclear magnetic resonance spectroscopy (NMR), gas chromatography–mass spectrometry (GC–MS) and various liquid chromatography–mass spectrometry (LC–MS) platforms. The analysis of liver fibrosis by each of these methodologies is reviewed separately. Surprisingly, there was little general agreement between studies within each of these three groups and also between groups. The metabolomic footprint determined by NMR (two or more hits between studies) comprised elevated lactate, acetate, choline, 3-hydroxybutyrate, glucose, histidine, methionine, glutamine, phenylalanine, tyrosine and citrate. For GC–MS, succinate, fumarate, malate, ascorbate, glutamate, glycine, serine and, in agreement with NMR, glutamine, phenylalanine, tyrosine and citrate were delineated. For LC–MS, only β-muricholic acid, tryptophan, acylcarnitine, p-cresol, valine and, in agreement with NMR, phosphocholine were identified. The metabolomic footprint of liver fibrosis was upregulated as regards glutamine, phenylalanine, tyrosine, citrate and phosphocholine. Several investigators employed traditional Chinese medicine (TCM) treatments to reverse experimental liver fibrosis, and a commentary is given on the chemical constituents that may possess fibrolytic activity. It is proposed that molecular docking procedures using these TCM constituents may lead to novel therapies for liver fibrosis affecting at least one-in-twenty persons globally, for which there is currently no pharmaceutical cure. This in-depth review summarizes the relevant literature on metabolomics and its implications in addressing the clinical problem of liver fibrosis, cirrhosis and its sequelae. [ABSTRACT FROM AUTHOR]

Metabolomics is one of the "omics" sciences that can reveal the metabolic phenotype of organisms. This capability makes it a valuable tool for plant investigation, as plants present a vast chemical diversity. From the analytical point of view, two main techniques are frequently used in metabolomics and are often complementary: Mass spectrometry (MS) and Nuclear Magnetic Resonance (NMR) spectroscopy. Here, we describe NMR and its applications in plant metabolomics. We start by contextualizing the research field to then explore study design, sample collection, sample preparation, NMR data acquisition, and data analysis, showing the key features for achieving quality and relevant results. Within these topics, the most common databases used for plant metabolites identification and assignments are listed, as these help to shorten the laborious task of metabolomics investigation of natural products. Concerning NMR parameters, we discuss the key pulse sequences, recommend acquisition parameters, and examine the data each sequence can provide. Similarly, we delve into data analysis, highlighting the most commonly used chemometric methods and how to achieve high-quality results. Therefore, this review aims to provide a comprehensive guide for NMR-based metabolomics analysis of plants. [ABSTRACT FROM AUTHOR]

In this contribution, we report the study of nuclear resonance magnetic spectroscopy techniques (1H-NMR, 13C-NMR, and 2D-NMR) efficiency in the characterisation of the functional composition of water-soluble organic compounds (WSOC) from atmospheric aerosols. The chosen site was our scientific and technical center of research (CRAPC) situated in Algerian Bou-Ismail city. where the concentrations of PM10 were found to be between 15.66 and 142.19 µg.m−3. As results, 1H-NMR analysis showed the coexistence of biological material and emissions from urban and biomass burning. The dominant source was identified by quantitative integration of each 1H NMR spectral region. By using the HSQC technique, many peaks are revealed in biogenic samples including biomass burning. On the other hand, the identification of the source of various organic compounds and their functional composition is possible through specific NMR spectra, which can also be used to adjust the surrounding organic aerosol sources. [ABSTRACT FROM AUTHOR]

Sesquiterpene lactones (SL) represent a class of secondary metabolites found in the Asteraceae family, notable for their unique structures. The SL α‐santonin (1) and its derivatives are worthy of mention due to their diverse biological properties. Additionally, 4H‐chromenes and 4H‐chromones are appealing frameworks holding the capability to be used as structural motifs for new drugs. Furthermore, unambiguous structural elucidation is crucial for developing novel compounds for diverse applications. In this context, it is common to find in the literature molecules erroneously assigned. Therefore, the use of quantum mechanical calculations to simulate NMR chemical shifts has emerged as a valuable strategy. In this work, we conceived the synthesis of two halogenated 4H‐chromenediones derived from photosantonic acid (2), a photoproduct arising from irradiation of α‐santonin (1) in the ultraviolet region. The structure of the chlorinated and brominated products was determined by NMR analysis, with the aid of quantum mechanical calculations at the B3LYP/6‐311 + G(2d,p)//M062x/6‐31 + G(d,p) level of theory. All analyses were in agreement and led to the assignment of the brominated 4H‐chromene‐2,7‐dione as (3S,3aS,5aR,9bS)‐5a‐(2‐bromopropan‐2‐yl)‐3‐methyl‐3,3a,5,5a,8,9b‐hexahydro‐4H‐furo[2,3‐f]chromene‐2,7‐dione (11b) and of the chlorinated 4H‐chromene‐2,7‐dione as (3S,3aS,5aR,9bS)‐5a‐(2‐chloropropan‐2‐yl)‐3‐methyl‐3,3a,5,5a,8,9b‐hexahydro‐4H‐furo[2,3‐f]chromene‐2,7‐dione (12b). The diastereoselectivities of the reactions were explained based on products and intermediates formation energy calculated using B3LYP/6‐31 + G(d,p) as the level of theory. Structures 11b and 12b were identified as the thermodynamic and kinetic products of the reaction among all candidates. Consequently, the strategy utilized in this study is robust and successfully illustrates the use of quantum mechanical calculations in the structural elucidation of new compounds with potential applications as novel drugs or products. [ABSTRACT FROM AUTHOR]

Summary: The impact of three food pasteurisation technologies, namely thermal, high‐pressure and ultra‐shear processing, on the metabolites of beetroot juice was evaluated using a processomics approach with nuclear mass resonance (NMR) as an analytical technique. Two batches of beetroots acquired from different local grocery stores were used for this study. Beetroot juice obtained from these batches was subjected to high‐pressure processing (HPP) at 600 MPa and 25 °C for 5 min, ultra‐shear technology processing (UST) at 400 MPa and 30 °C and thermal processing (TP) at 96 °C for 12 min. Principal component analysis (PCA) for the two batches indicated that both extrinsic factors such as processing parameters (temperature, pressure, shear and holding time) and intrinsic factors such as the origin of the beetroot influenced the PCA plot. When the influence of intrinsic parameters was minimised by studying a single batch processed by TP, HPP and UST, distinct clusters for different processing methods were formed, indicating that processing influenced the metabolites. While processing is not the main factor determining the final composition, as indicated by PCA with different batches, supervised techniques like orthogonal partial least‐squares discriminant analysis (OPLS‐DA) and random forest (RF) demonstrated that processing does impact the beetroot juice metabolome. Seven metabolites (leucine, alanine, valine, glutamine, gamma‐aminobutyric acid, fructose and glucose) were identified as potential process‐induced biomarkers. [ABSTRACT FROM AUTHOR]

Helicobacter pylori, a leading human pathogen associated with duodenal ulcer and gastric cancer, presents a significant threat to human health due to increasing antibiotic resistance rates. This study investigates G‐quadruplexes (G4s), which are non‐canonical secondary structures form in G‐rich regions within the H. pylori genome. Extensive research on G4s in eukaryotes has revealed their role in epigenetically regulating cellular processes like gene transcription, DNA replication, and oncogene expression. However, understanding of G4‐mediated gene regulation in other organisms, especially bacterial pathogens, remains limited. Although G4 motifs have been extensively studied in a few bacterial species such as Mycobacterium, Streptococci, and Helicobacter, research on G4 motifs in other bacterial species is still sparse. Like in other organisms such as archaea, mammals, and viruses, G4s in H. pylori display a non‐random distribution primarily situated within open reading frames of various protein‐coding genes. The occurrence of G4s in functional regions of the genome and their conservation across different species indicates that their placement is not random, suggesting an evolutionary pressure to maintain these sequences at specific genomic sites. Moreover, G‐quadruplexes show enrichment in specific gene classes, suggesting their potential involvement in regulating the expression of genes related to cell wall/membrane/envelope biogenesis, amino acid transport, and metabolism. This indicates a probable regulatory role for G4s in controlling the expression of genes essential for H. pylori survival and virulence. Biophysical techniques such as Circular Dichroism spectroscopy and Nuclear Magnetic Resonance were used to characterize G4 motifs within selected H. pylori genes. The study revealed that G‐quadruplex ligand inhibited the growth of H. pylori, with minimal inhibitory concentrations in the low micromolar range. This suggests that targeting G4 structures could offer a promising approach for developing novel anti‐H. pylori drugs. [ABSTRACT FROM AUTHOR]

The characteristics and heterogeneity of coal pores are crucial for understanding the production mechanism of coalbed methane (CBM). In this study, coal samples with varying degrees of metamorphism (0.58% ≤ RO, max ≤ 3.44%) were collected. The characteristics of pore development and the heterogeneous properties of pores were revealed through low-temperature nitrogen adsorption (LTNA) and low-field nuclear magnetic resonance (NMR) experiments. The results indicate that pores with varying diameters exhibit favorable development in low-rank coals, along with favorable pores connectivity. The micropores composition of middle-rank coals was found to be 73.56%, however, the connectivity among transitional, meso, and macropores was observed to be poor. In high-rank coals, the proportion of micropores was 92.74%, with numerous micropores being closed or semi-closed. This resulted in inferior connectivity between micropores and transitional pores. As coal metamorphism progressed, the DL1 (characterizing the roughness of adsorption pores (AP) surface, ranging from 2.13 to 2.45) and DL2 (characterizing the complexity of AP structure, ranging from 2.56 to 2.77) initially decreased and then increased, whereas the DN (characterizing the heterogeneity of seepage pores (SP), ranging from 2.92 to 2.95) consistently improved. Furthermore, the roughness of pore surface and the complexity of pore structure in AP increased as the specific surface area and volume of pores increased. On the contrary, as the SP content increased, the uniformity of the pore structure improved. When the volume of SP remained constant, the complexity of the pore structure decreased due to increased pore connectivity. [ABSTRACT FROM AUTHOR]

Although beryllium and its compounds show outstanding properties, owing to its toxic potential and extreme reaction conditions the chemistry of Be under high‐pressure conditions has only been investigated sparsely. Herein, we report on the highly condensed wurtzite‐type Be2PN3, which was synthesized from Be3N2 and P3N5 in a high‐pressure high‐temperature approach at 9 GPa and 1500 °C. It is the missing member in the row of formula type M2PN3 (M = Mg, Zn). The structure was elucidated by powder X‐ray diffraction (PXRD), revealing that Be2PN3 is a double nitride, rather than a nitridophosphate. The structural model was further corroborated by 9Be and 31P solid‐state nuclear magnetic resonance (NMR) spectroscopy. We present 9Be NMR data for tetrahedral nitride coordination for the first time. Infrared and energy‐dispersive X‐ray spectroscopy (FTIR and EDX), as well as temperature dependent PXRD complement the analytical characterization. Density functional theory (DFT) calculations reveal super‐incompressible behavior and the remarkable hardness of this low‐density material. The formation of Be2PN3 through a high‐pressure high‐temperature approach expands the synthetic access to Be‐containing compounds and may open access to various multinary beryllium nitrides. [ABSTRACT FROM AUTHOR]

Although beryllium and its compounds show outstanding properties, owing to its toxic potential and extreme reaction conditions the chemistry of Be under high‐pressure conditions has only been investigated sparsely. Herein, we report on the highly condensed wurtzite‐type Be2PN3, which was synthesized from Be3N2 and P3N5 in a high‐pressure high‐temperature approach at 9 GPa and 1500 °C. It is the missing member in the row of formula type M2PN3 (M = Mg, Zn). The structure was elucidated by powder X‐ray diffraction (PXRD), revealing that Be2PN3 is a double nitride, rather than a nitridophosphate. The structural model was further corroborated by 9Be and 31P solid‐state nuclear magnetic resonance (NMR) spectroscopy. We present 9Be NMR data for tetrahedral nitride coordination for the first time. Infrared and energy‐dispersive X‐ray spectroscopy (FTIR and EDX), as well as temperature dependent PXRD complement the analytical characterization. Density functional theory (DFT) calculations reveal super‐incompressible behavior and the remarkable hardness of this low‐density material. The formation of Be2PN3 through a high‐pressure high‐temperature approach expands the synthetic access to Be‐containing compounds and may open access to various multinary beryllium nitrides. [ABSTRACT FROM AUTHOR]

This study focuses on the synthesis and structural characterization of new compounds that integrate thiazolidine-2,4-dione, acridine moiety, and an acetamide linker, aiming to leverage the synergistic effects of these pharmacophores for enhanced therapeutic potential. The newly designed molecules were efficiently synthesized through a multi-step process and subsequently transformed into their hydrochloride salts. Comprehensive spectroscopic techniques, including nuclear magnetic resonance (NMR), high-resolution mass spectrometry (HRMS), infrared (IR) spectroscopy, and elemental analysis, were employed to determine the molecular structures of the synthesized compounds. Biological evaluations were conducted to assess the therapeutic potential of the new compounds. The influence of these derivatives on the metabolic activity of various cancer cell lines was assessed, with IC50 values determined via MTT assays. An in-depth analysis of the structure–activity relationship (SAR) revealed intriguing insights into their cytotoxic profiles. Compounds with electron-withdrawing groups generally exhibited lower IC50 values, indicating higher potency. The presence of the methoxy group at the linking phenyl ring modulated both the potency and selectivity of the compounds. The variation in the acridine core at the nitrogen atom of the thiazolidine-2,4-dione core significantly affects the activity against cancer cell lines, with the acridin-9-yl substituent enhancing the compounds' antiproliferative activity. Furthermore, compounds in their hydrochloride salt forms demonstrated better activity against cancer cell lines compared to their free base forms. Compounds 12c·2HCl (IC50 = 5.4 ± 2.4 μM), 13d (IC50 = 4.9 ± 2.9 μM), and 12f·2HCl (IC50 = 4.98 ± 2.9 μM) demonstrated excellent activity against the HCT116 cancer cell line, and compound 7d·2HCl (IC50 = 4.55 ± 0.35 μM) demonstrated excellent activity against the HeLa cancer cell line. Notably, only a few tested compounds, including 7e·2HCl (IC50 = 11.00 ± 2.2 μM), 7f (IC50 = 11.54 ± 2.06 μM), and 7f·2HCl (IC50 = 9.82 ± 1.92 μM), showed activity against pancreatic PATU cells. This type of cancer has a very high mortality due to asymptomatic early stages, the occurrence of metastases, and frequent resistance to chemotherapy. Four derivatives, namely, 7e·2HCl, 12d·2HCl, 13c·HCl, and 13d, were tested for their interaction properties with BSA using fluorescence spectroscopic studies. The values for the quenching constant (Ksv) ranged from 9.59 × 104 to 10.74 × 104 M−1, indicating a good affinity to the BSA protein. [ABSTRACT FROM AUTHOR]

Although beryllium and its compounds show outstanding properties, owing to its toxic potential and extreme reaction conditions the chemistry of Be under high‐pressure conditions has only been investigated sparsely. Herein, we report on the highly condensed wurtzite‐type Be2PN3, which was synthesized from Be3N2 and P3N5 in a high‐pressure high‐temperature approach at 9 GPa and 1500 °C. It is the missing member in the row of formula type M2PN3 (M = Mg, Zn). The structure was elucidated by powder X‐ray diffraction (PXRD), revealing that Be2PN3 is a double nitride, rather than a nitridophosphate. The structural model was further corroborated by 9Be and 31P solid‐state nuclear magnetic resonance (NMR) spectroscopy. We present 9Be NMR data for tetrahedral nitride coordination for the first time. Infrared and energy‐dispersive X‐ray spectroscopy (FTIR and EDX), as well as temperature dependent PXRD complement the analytical characterization. Density functional theory (DFT) calculations reveal super‐incompressible behavior and the remarkable hardness of this low‐density material. The formation of Be2PN3 through a high‐pressure high‐temperature approach expands the synthetic access to Be‐containing compounds and may open access to various multinary beryllium nitrides. [ABSTRACT FROM AUTHOR]

Although beryllium and its compounds show outstanding properties, owing to its toxic potential and extreme reaction conditions the chemistry of Be under high‐pressure conditions has only been investigated sparsely. Herein, we report on the highly condensed wurtzite‐type Be2PN3, which was synthesized from Be3N2 and P3N5 in a high‐pressure high‐temperature approach at 9 GPa and 1500 °C. It is the missing member in the row of formula type M2PN3 (M = Mg, Zn). The structure was elucidated by powder X‐ray diffraction (PXRD), revealing that Be2PN3 is a double nitride, rather than a nitridophosphate. The structural model was further corroborated by 9Be and 31P solid‐state nuclear magnetic resonance (NMR) spectroscopy. We present 9Be NMR data for tetrahedral nitride coordination for the first time. Infrared and energy‐dispersive X‐ray spectroscopy (FTIR and EDX), as well as temperature dependent PXRD complement the analytical characterization. Density functional theory (DFT) calculations reveal super‐incompressible behavior and the remarkable hardness of this low‐density material. The formation of Be2PN3 through a high‐pressure high‐temperature approach expands the synthetic access to Be‐containing compounds and may open access to various multinary beryllium nitrides. [ABSTRACT FROM AUTHOR]

Octreotide acetate, the active pharmaceutical ingredient in the long‐acting release (LAR) drug product Sandostatin®, is a cyclic octapeptide that mimics the naturally occurring somatostatin peptide hormone. Modern NMR can be a robust analytical method to identify and quantify octreotide molecules. Previous 1H chemical shift assignments were mostly performed in organic solvents, and no assignments for heteronuclear 13C, 15N, and aromatic 1H nuclei are available. Here, using state‐of‐the‐art 1D and 2D homo‐ and heteronuclear NMR experiments, octreotide was fully assigned, including water exchangeable amide protons, in aqueous buffer except for 13CO and 15NH of F1, 15NH of C2, and 15NζHζ of K5 that were not observed because of water exchange or conformational exchange. The solution NMR spectra were then directly compared with 1D 1H/13C/15N solid‐state NMR (SSNMR) spectra showing the potential applicability of 13C/15N SSNMR for octreotide drug product characterization. [ABSTRACT FROM AUTHOR]

Metabolomic age models have been proposed for the study of biological aging, however, they have not been widely validated. We aimed to assess the performance of newly developed and existing nuclear magnetic resonance spectroscopy (NMR) metabolomic age models for prediction of chronological age (CA), mortality, and age‐related disease. Ninety‐eight metabolic variables were measured in blood from nine UK and Finnish cohort studies (N ≈31,000 individuals, age range 24–86 years). We used nonlinear and penalized regression to model CA and time to all‐cause mortality. We examined associations of four new and two previously published metabolomic age models, with aging risk factors and phenotypes. Within the UK Biobank (N ≈102,000), we tested prediction of CA, incident disease (cardiovascular disease (CVD), type‐2 diabetes mellitus, cancer, dementia, and chronic obstructive pulmonary disease), and all‐cause mortality. Seven‐fold cross‐validated Pearson's r between metabolomic age models and CA ranged between 0.47 and 0.65 in the training cohort set (mean absolute error: 8–9 years). Metabolomic age models, adjusted for CA, were associated with C‐reactive protein, and inversely associated with glomerular filtration rate. Positively associated risk factors included obesity, diabetes, smoking, and physical inactivity. In UK Biobank, correlations of metabolomic age with CA were modest (r = 0.29–0.33), yet all metabolomic model scores predicted mortality (hazard ratios of 1.01 to 1.06/metabolomic age year) and CVD, after adjustment for CA. While metabolomic age models were only moderately associated with CA in an independent population, they provided additional prediction of morbidity and mortality over CA itself, suggesting their wider applicability. [ABSTRACT FROM AUTHOR]

[Display omitted] Hypothesis: Limited research has been conducted on the influence of chelating agents on the self-assembly process in surfactant solutions. The traditional approach assumes the chelating agent only interferes as a salting-out ion, therefore promoting surfactant separation. However, the opposite behavior has been observed for iminodipropionate based surfactants, in which the presence of chelating agents of the aminopolycarboxylate type increases solubility of nonionic ethoxylated surfactants in mixed micellar systems. Specific interaction between chelating agents-surfactants can be an important parameter in the self-assembly processes. Experiments: Physicochemical properties of solutions containing amphoteric surfactant and tetrasodium glutamatediacetate have been investigated. Macroscopic properties, such as viscosity and cloud point, were evaluated in the presence of a non-water-soluble alkyl ethoxylated surfactant. Interactions between amphoteric surfactant and chelating agent were monitored by NMR spectroscopy, including 13C chemical shift and lineshape analysis as well as 1H diffusometry. Findings: The study reveals that there is an interaction between the head group of the surfactant and the chelating agent forming oligomeric surfactant analogues with larger hydrophilic moieties, which results in smaller, more spherical micelles. The combined interactions provide possibilities for tuning the aggregation behavior of systems containing surfactants and chelating agents, and with that, the macroscopic properties of the system. [ABSTRACT FROM AUTHOR]

Multi‐exponential decay is prevalent in magnetic resonance spectroscopy, relaxation, and imaging. This paper describes simple MATLAB and Python functions and scripts for regularized multi‐exponential analysis methods for 1D and 2D data and example test problems and experiments. Regularized least‐squares solutions provide production‐quality outputs with robust stopping rules in ~5 and ~20 lines of code for 1D and 2D inversions, respectively. The software provides an open‐architecture simple solution for transforming exponential decay data to the distribution of their decay lifetimes. Examples from magnetic resonance relaxation of a complex fluid, a Danish North Sea crude oil, and fluid mixtures in porous materials—brine/crude oil mixture in North Sea reservoir chalk—are presented. Developed codes may be incorporated in other software or directly used by other researchers, in magnetic resonance relaxation, diffusion, and imaging or other physical phenomena that require multi‐exponential analysis. [ABSTRACT FROM AUTHOR]

Pathogenic huntingtin exon‐1 protein (httex1), characterized by an expanded polyglutamine tract located between the N‐terminal amphiphilic region and a C‐terminal polyproline‐rich domain, forms fibrils that accumulate in neuronal inclusion bodies, and is associated with a fatal, autosomal dominant neurodegenerative condition known as Huntington's disease. Here a complete kinetic model is described for aggregation/fibril formation of a httex1 construct with a 35‐residue polyglutamine repeat, httex1Q35. Using exchange NMR spectroscopy, it is previously shown that the reversible formation of a sparsely‐populated tetramer of the N‐terminal amphiphilic domain of httex1Q35, comprising a D2 symmetric four‐helix bundle, occurs on the microsecond time‐scale and is a prerequisite for subsequent nucleation and fibril formation on a time scale that is many orders of magnitude slower (hours). Here a unified kinetic model of httex1Q35 aggregation is developed in which fast, reversible tetramerization is directly linked to slow irreversible fibril formation via conversion of pre‐equilibrated tetrameric species to "active", chain elongation‐capable nuclei by conformational re‐arrangement with a finite, monomer‐independent rate. The unified model permits global quantitative analysis of reversible tetramerization and irreversible fibril formation from a time series of 1H‐15N correlation spectra recorded during the course of httex1Q35 aggregation. [ABSTRACT FROM AUTHOR]

Featured Application: Machine learning in forensic science and the use of MATLAB for identification and classification of petrol source. Petrol is considered the most common fire accelerant. However, the identification and classification of petrol sources through the years has proven to be a challenging field in the investigation of fire debris analysis. This research explored the possibility of identifying petrol sources by high-field NMR methods accompanied by ML (machine learning). The automated identification and classification of petrol brands were achieved for first time based on the ML classification model developed in this research. A hierarchical classification model was constructed using local classifiers to categorize neat or weathered petrol into its sources. [ABSTRACT FROM AUTHOR]

Chemical activation of the nuclear singlet state of dihydrogen, para‐hydrogen, can dramatically increase the sensitivity of magnetic resonance spectroscopy and imaging. Here, we show that the highly reversible activation of para‐hydrogen by an iridium pyridylpyrrolide complex is capable of producing this hyperpolarisation effect. Bound alkene ligands exhibit signal enhancement without reduction to alkanes, which is in contrast to the most widely used hyperpolarisation catalysts. The complex is recoverable due to the highly reversible binding and release of H2, and result in enhanced hydride signals in a wide range of coordinating and non‐coordinating deuterated solvents. Synthetic modification of the ligand substituents and the addition of co‐ligands show a strong dependence of chemical structure on reactivity, which reveals an untapped potential to exploit pyridylpyrrolides as ligands in the development of tunable para‐hydrogen induced hyperpolarisation catalysts or molecular probes. [ABSTRACT FROM AUTHOR]

Polaritonic chemistry is emerging as a powerful approach to modifying the properties and reactivity of molecules and materials. However, probing how the electronics and dynamics of molecular systems change under strong coupling has been challenging due to the narrow range of spectroscopic techniques that can be applied in situ. Here we develop microfluidic optical cavities for vibrational strong coupling (VSC) that are compatible with nuclear magnetic resonance (NMR) spectroscopy using standard liquid NMR tubes. VSC is shown to influence the equilibrium between two conformations of a molecular balance sensitive to London dispersion forces, revealing an apparent change in the equilibrium constant under VSC. In all compounds studied, VSC does not induce detectable changes in chemical shifts, J‐couplings, or spin‐lattice relaxation times. This unexpected finding indicates that VSC does not substantially affect molecular electron density distributions, and in turn has profound implications for the possible mechanisms at play in polaritonic chemistry under VSC and suggests that the emergence of collective behavior is critical. [ABSTRACT FROM AUTHOR]

Quasi-equilibrium states that can be prepared in solids through Nuclear Magnetic Resonance (NMR) techniques are out-of-equilibrium states that slowly relax towards thermodynamic equilibrium with the lattice. In this work, we use the quantum discord dynamics as a witness of the quantum correlation in this kind of state. The studied system is a set of dipole interacting spin pairs whose initial state is prepared with the NMR Jeener–Broekaert pulse sequence, starting from equilibrium at high temperature and high external magnetic field. It then evolves as an open quantum system within two consecutive dynamic scenarios: adiabatic decoherence driven by the coupling of the pairs to a common phonon field, described within a non-Markovian approach, and spin–lattice relaxation represented by the high-temperature limit of the Born–Markov master equation, and driven by thermal fluctuations. In this way, the studied model is endowed with the dynamics of a realistic solid sample. The quantum discord rapidly increases during the preparation of the initial state, escalating several orders of magnitude compared with thermal equilibrium at room temperature. During decoherence—despite the decay of coherences—the quantum discord oscillates upon this high value, holding the same value as the initial state. Finally, the quantum discord dissipates within a time scale shorter than but comparable to spin–lattice relaxation. [ABSTRACT FROM AUTHOR]

Simple Summary: Cervical cancer is the fourth most prominent cancer in women worldwide. Early cancer detection, timely treatment, and prognostic marker identification are vital to ensure that patients have improved outcomes. Magnetic resonance spectroscopy (MRS) is a powerful tool for detecting metabolites in vivo. This review article covers the role of MRS for cervical cancer for diagnosis, treatment response evaluation, and future applications of this technology. This review article investigates the utilization of MRS in the setting of cervical cancer. A variety of different techniques have been used in this space including single-voxel techniques such as point-resolved spectroscopy (PRESS) and stimulated echo acquisition mode spectroscopy (STEAM). Furthermore, the experimental parameters for these acquisitions including field strength, repetition times (TR), and echo times (TE) vary greatly. This study critically examines eleven MRS studies that focus on cervical cancer. Out of the eleven studies, ten studies utilized PRESS acquisition, while the remaining study used STEAM acquisition. These studies generally showed that the choline signal is altered in cervical cancer (4/11 studies), the lipid signal is generally increased in cervical cancer or the lipid distribution is changed (5/11 studies), and that diffusion-weighted imaging (DWI) can quantitatively detect lower apparent diffusion coefficient (ADC) values in cervical cancer (2/11 studies). Two studies also investigated the role of MRS for monitoring treatment response and demonstrated mixed results regarding choline signal, and one of these studies showed increased lipid signal for non-responders. There are several new MRS technologies that have yet to be implemented for cervical cancer including advanced spectroscopic imaging and artificial intelligence, and those technologies are also discussed in the article. [ABSTRACT FROM AUTHOR]

Histone deacetylase 6 (HDAC6) is increasingly recognized for its potential in targeted disease therapy. This study delves into the mechanistic and structural nuances of HDAC6 inhibition by difluoromethyl-1,3,4-oxadiazole (DFMO) derivatives, a class of non-hydroxamic inhibitors with remarkable selectivity and potency. Employing a combination of nuclear magnetic resonance (NMR) spectroscopy and liquid chromatography-mass spectrometry (LC-MS) kinetic experiments, comprehensive enzymatic characterizations, and X-ray crystallography, we dissect the intricate details of the DFMO-HDAC6 interaction dynamics. More specifically, we find that the chemical structure of a DMFO and the binding mode of its difluoroacetylhydrazide derivative are crucial in determining the predominant hydrolysis mechanism. Our findings provide additional insights into two different mechanisms of DFMO hydrolysis, thus contributing to a better understanding of the HDAC6 inhibition by oxadiazoles in disease modulation and therapeutic intervention. [ABSTRACT FROM AUTHOR]

Recently, we applied solution 2H-nuclear magnetic resonance spectroscopy (2H NMR) to analyze the water (deuterium oxide, D2O) structure in several biopolymers at ambient temperature. We established that polymers with good blood compatibility (i.e. poly(2-methoxyethyl acrylate) (PMEA)) have water observed at high magnetic fields (upfield) compared with bulk water. Polymers containing poly(propylene glycol) (PPG) or poly(propylene oxide) (PPO) exhibit good compatibility; however, the reason for this remains unclear. In addition, reports on the blood compatibility of PPO/PPG are limited. Therefore, PPG diester (PPGest) was prepared as a model polymer, and its blood compatibility and water structure were investigated. PPGest exhibited excellent blood compatibility. The water in PPGest was observed upfield by 2H NMR, and it was defined as non-freezing water via differential scanning calorimetry. Based on these observations, the relationship between the blood compatibility and water structure of PPGest is discussed by comparing with those of PMEA, and the reason for the good performance of PPG/PPO-based polymers is discussed. [ABSTRACT FROM AUTHOR]

Dendrobium officinale (D. officinale) as a well-known herbal and functional food material is often adulterated with lower-price Dendrobium species. In this study, we aimed to develop an integrated method of nuclear magnetic resonance spectroscopy and artificial neural network (NMR-ANN) to identify and quantify the adulteration of D. officinale powder with other cheaper species. Microwave-assisted water extraction was selected as a time-saving and green method for sample preparation. The results indicate that the NMR-ANN method effectively quantified the adulteration rate of D. officinale powder with the root mean squared error (RMSE) of 4.92, mean absolute error (MAE) of 3.56 and coefficient of determination (R2) of 0.98 in the model test phase and with the RMSE of 7.65, MAE of 6.30 and R2 of 0.98 in the double-blinded test phase. The whole evaluation process can be done in 6 min and 5 s. Therefore, the NMR-ANN method can be used as a rapid, green and accurate tool for evaluating the quality of D. officinale or even other food materials. [ABSTRACT FROM AUTHOR]

To clarify the evolution of thermal maturity and pore structure in continental organic-rich shales, calcareous shales of the Liaohe Basin (China) were pyrolyzed, and examined using Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), nitrogen sorption isotherms, and nuclear magnetic resonance (NMR) spectroscopy. The increase in Raman G-D band separation and decrease in Raman ID/IG ratio with increasing thermal maturity indicate that these parameters provide superior thermal maturity indicators. This is also confirmed by the good linear correlation of G-D band shifts and ID/IG with vitrinite reflectance (VR) and maximum temperature (Tmax), respectively. The relative detection accuracy (DA), sampling requirements (SR), sample preparation (SP), detection time (DT), and equipment requirement (ER) of VR, G-D band shifts, ID/IG, Tmax, FTIR, and XPS indicate that Raman analysis is a simple, quick, and robust method to evaluate thermal maturity. The moderate SR, complex SP, and long DT suggest that VR and Tmax are less widely applicable for characterizing thermal maturity. The FTIR and XPS techniques provide semi-quantitative maturity indicators with poor DA and high ER. Pores observed within organic matter and minerals under SEM indicate that an increase in thermal maturity not only affects the development of organic pores but is also beneficial for the formation of mineral dissolution pores, such as those formed during the transformation of Na0 95Ca016Al1 16Si2 84O8 to Na0 84Ca0 02Al1 02Si2 98O8, a process confirmed by XRD. The BET and NMR data also indicate that the development of pore structure is closely related to the evolution of thermal maturity in calcareous shale . During the initial stage, primary pores are filled by bitumen generated from kerogen; this leads to a decrease in transition pores, mesopores, and shale porosity, and reduced pore connectivity. Then, secondary nanoscale pores, transition pores, and mesopores increase with increasing thermal maturity. The peak in secondary porosity is consistent with the liquid hydrocarbon production rate peak, a process that increases shale porosity and leads to improved pore connectivity. The dissolution of minerals induced by organic acids may also contribute to this secondary porosity. With a further increase in thermal maturity, secondary porosity at the microscale is further developed, while transition pores and mesopores collapse, resulting in reduced pore connectivity. The poor pore connectivity that occurs at both low and high VR values may be more conducive to the preservation of shale oil and gas. This study is significant for research into the evolution of thermal maturity and pore structure in continental organic-rich shales. [ABSTRACT FROM AUTHOR]

The current study explains the degradation behavior of Febuxostat API, a non‐purine xanthine oxidase inhibitor used to treat hyperuricemia. A degradation study was carried out as per the International Council for Harmonization of Technical Requirements for Pharmaceuticals for Human Use (ICH) guidelines, and the study confirms that the Febuxostat is largely stable in thermal, photolytic, oxidative, and basic hydrolytic conditions and labile in acid hydrolysis conditions. There were four different degradation products (DPs) found during acid hydrolysis; of these, DPs 2, 3, and 4 are new and have never been reported before, while DP 1 is known and has already been published. All these DPs were identified using ultra‐high‐performance liquid chromatography‐mass spectrometry (UHPLC‐MS) analysis, purified by using preparative HPLC, and characterized using high‐resolution mass spectrometry (HRMS) and nuclear magnetic resonance (NMR) spectroscopy techniques. The formed DPs are by the hydrolysis of the cyano functional group of Febuxostat and the esterification of DP‐1 under acidic conditions. All DP's structural characterization was carried out using NMR spectroscopy and HRMS. The present study describes concrete confirmation of DP structures and it explains the stability behavior of the Febuxostat. The current method is also used to identify DPs with shorter runtime in the future. [ABSTRACT FROM AUTHOR]

Although both localized nuclear magnetic resonance spectroscopy (MRS) and non-localized nuclear magnetic resonance spectroscopy (NMR) generate the same information, i.e., spectra generated by various groups from the structure of metabolites, they are rarely employed in the same study or by the same research group. As our review reveals, these techniques have never been applied in the same study of methylmalonic acidemia (MMA), propionic acidemia (PA) or vitamin B12 deficiency patients. On the other hand, MRS and NMR provide complementary information which is very valuable in the assessment of the severity of disease and efficiency of its treatment. Thus, MRS provides intracellular metabolic information from localized regions of the brain, while NMR provides extracellular metabolic information from biological fluids like urine, blood or cerebrospinal fluid. This paper presents an up-to-date review of the NMR and MRS studies reported to date for methylmalonic and propionic acidemias. Vitamin B12 deficiency, although in most of its cases not inherited, shares similarities in its metabolic effects with MMA and it is also covered in this review. [ABSTRACT FROM AUTHOR]

Orb-weaver spiders produce upwards of seven different types of silk, each with unique material properties. We focus on the adhesive within orb-weaving spider webs, aggregate glue silk. These droplets are composed of three main components: water, glycoproteins, and a wide range of low molecular mass compounds (LMMCs). These LMMCs are known to play a crucial role in maintaining the material properties of the glycoproteins, aid in water absorption from the environment, and increase surface adhesion. Orb-weavers within the Cyrtarachninae subfamily are moth specialists and have evolved glue droplets with novel material properties. This study investigated the biochemical composition and diversity of the LMMCs present in the aggregate glue of eight moth-specialist species and compared them with five generalist orb-weavers using nuclear magnetic resonance (NMR) spectroscopy. We hypothesized that the novel drying ability of moth-specialist glue was accompanied by novel LMMCs and lower overall percentages by silk weight of LMMCs. We measured no difference in LMMC weight by the type of prey specialization, but observed novel compositions in the glue of all eight moth-catching species. Further, we quantified the presence of a previously reported but unidentified compound that appears in the glue of all moth specialists. These silks can provide insight into the functions of bioadhesives and inform our own synthetic adhesives. [ABSTRACT FROM AUTHOR]

New dammarane-type triterpenoid saponin, named 22(R)-notoginsenoside Ab1 (1), together with thirteen known dammarane-type triterpenoid saponins (2-14) was isolated from the EtOH extract of black ginseng and their structures were elucidated on the basis of one- and two-dimensional NMR (including 1H-NMR, 13C-NMR, HSQC, HMBC, ROESY) and calculated ECD. Among them, compounds 1-2 and 6-8 were isolated for the first time from ginseng and black ginseng. Besides, the absolute structure of 22(R)- and 22(S)- notoginsenoside Ab1 were distinguished by ECD for the first time. [ABSTRACT FROM AUTHOR]

Metabolomics can allow for the comprehensive identification of metabolites within biological systems, at given time points, in physiological and pathological conditions. In the last few years, metabolomic analysis has gained popularity both in human and in veterinary medicine, showing great potential for novel applications in clinical activity. The aim of applying metabolomics in clinical practice is understanding the mechanisms underlying pathological conditions and the influence of certain stimuli (i.e., drugs, nutrition, exercise) on body systems, in the attempt of identifying biomarkers that can help in the diagnosis of diseases. Proton Nuclear Magnetic Resonance spectroscopy (1H-NMR) is well tailored to be used as an analytical platform for metabolites' detection at the base of metabolomics studies, due to minimal sample preparation and high reproducibility. In this mini-review article, the scientific production of NMR metabolomic applications to equine medicine is examined. The research works are very different in methodology and difficult to compare. Studies are mainly focused on exercise, reproduction, and nutrition, other than respiratory and musculoskeletal diseases. The available information on this topic is still scant, but a greater collection of data could allow researchers to define new reliable markers to be used in clinical practice for diagnostic and therapeutical purposes. [ABSTRACT FROM AUTHOR]

Metabolomics has proven to be a sensitive tool for monitoring biochemical processes in cell culture. It enables multi-analysis, clarifying the correlation between numerous metabolic pathways. Together with other analysis, it thus provides a global view of a cell's physiological state. A comprehensive analysis of molecular changes is also required in the case of mesenchymal stem cells (MSCs), which currently represent an essential portion of cells used in regenerative medicine. Reproducibility and correct measurement are closely connected to careful metabolite extraction, and sample preparation is always a critical point. Our study aimed to compare the efficiencies of four harvesting and six extraction methods. Several organic reagents (methanol, ethanol, acetonitrile, methanol–chloroform, MTBE) and harvesting approaches (trypsinization vs. scraping) were tested. We used untargeted nuclear magnetic resonance spectroscopy (NMR) to determine the most efficient method for the extraction of metabolites from human adherent cells, specifically human dermal fibroblasts adult (HDFa) and dental pulp stem cells (DPSCs). A comprehensive dataset of 29 identified and quantified metabolites were determined to possess statistically significant differences in the abundances of several metabolites when the cells were detached mechanically to organic solvent compared to when applying enzymes mainly in the classes of amino acids and peptides for both types of cells. Direct scraping to organic solvent is a method that yields higher abundances of determined metabolites. Extraction with the use of different polar reagents, 50% and 80% methanol, or acetonitrile, mostly showed the same quality. For both HDFa and DPSC cells, the MTBE method, methanol–chloroform, and 80% ethanol extractions showed higher extraction efficiency for the most identified and quantified metabolites Thus, preparation procedures provided a cell sample processing protocol that focuses on maximizing extraction yield. Our approach may be useful for large-scale comparative metabolomic studies of human mesenchymal stem cell samples. [ABSTRACT FROM AUTHOR]

This study presents the synthesis and characterization of oxonitridosilicate phosphates Sr3SiP3O2N7, Sr5Si2P4ON12, and Sr16Si9P9O7N33 as the first of their kind. These compounds were synthesized under high‐temperature (1400 °C) and high‐pressure (3 GPa) conditions. A unique structural feature is their common fundamental building unit, a vierer single chain of (Si, P)(O, N)4 tetrahedra. All tetrahedra comprise substitutional disorder which is why we refer to it as the fundamental disorder unit (FDU). We classified four different FDU motifs, revealing systematic bonding patterns. Including literature known Sr5Si2P6N16, three of the four patterns were found in the presented compounds. Common techniques like single‐crystal X‐ray diffraction (SCXRD), elemental analyses, and 31P nuclear magnetic resonance (NMR) spectroscopy were utilized for structural analysis. Additionally, low‐cost crystallographic calculations (LCC) provided insights into the structure of Sr16Si9P9O7N33 where NMR data were unavailable due to the lack of bulk samples. The optical properties of these compounds, when doped with Eu2+, were investigated using photoluminescence excitation (PLE), photoluminescence (PL) measurements, and density functional theory (DFT) calculations. Factors influencing the emission properties, including thermal quenching mechanisms, were discussed. This research reveals the new class of oxonitridosilicate phosphates with unique systematic structural features that offer potential for theoretical studies of luminescence and band gap tuning in insulators. [ABSTRACT FROM AUTHOR]

Nuclear magnetic resonance (NMR) spectroscopy is a powerful tool for qualitative and quantitative analysis. However, for complex mixtures, determining the speciation from NMR spectra can be tedious and sometimes even unfeasible. On the other hand, identifying and quantifying structural groups in a mixture from NMR spectra is much easier than doing the same for components. We call this group‐based approach "NMR fingerprinting." In this work, we show that NMR fingerprinting can even be performed in an automated way, without expert knowledge, based only on standard NMR spectra, namely, 13C, 1H, and 13C DEPT NMR spectra. Our approach is based on the machine‐learning method of support vector classification (SVC), which was trained here on thousands of labeled pure‐component NMR spectra from open‐source data banks. We demonstrate the applicability of the automated NMR fingerprinting using test mixtures, of which spectra were taken using a simple benchtop NMR spectrometer. The results from the NMR fingerprinting agree remarkably well with the ground truth, which was known from the gravimetric preparation of the samples. To facilitate the application of the method, we provide an interactive website (https://nmr-fingerprinting.de), where spectral information can be uploaded and which returns the NMR fingerprint. The NMR fingerprinting can be used in many ways, for example, for process monitoring or thermodynamic modeling using group‐contribution methods—or simply as a first step in species analysis. [ABSTRACT FROM AUTHOR]

NMR methods were applied for lubricant analysis. Different factors influence the real aging of lubricants on diverse length scales and are captured by NMR. Chemical conversion of additives is addressed by NMR spectroscopy. High‐field NMR experiments allow the identification and quantification of chemical components and are transferred to benchtop devices. Molecular dynamics and contaminations like fuel or abrasion are addressed via NMR relaxation and diffusion. Quality parameters were extracted via suitable data analysis of NMR raw data, which allow the detection of aging and indicate changes in the oil composition. At the same time, the methodology is optimized to the conditions in quality control. The feasibility is shown the example of a series of lubricants from applications in regenerative energy production, namely, wind turbine oils and biogas motor oils. [ABSTRACT FROM AUTHOR]

Background: The National Cancer Institute issued a Request for Information (RFI; NOT-CA-23-007) in October 2022, soliciting input on using and reusing metabolomics data. This RFI aimed to gather input on best practices for metabolomics data storage, management, and use/reuse. Aim of review: The nuclear magnetic resonance (NMR) Interest Group within the Metabolomics Association of North America (MANA) prepared a set of recommendations regarding the deposition, archiving, use, and reuse of NMR-based and, to a lesser extent, mass spectrometry (MS)-based metabolomics datasets. These recommendations were built on the collective experiences of metabolomics researchers within MANA who are generating, handling, and analyzing diverse metabolomics datasets spanning experimental (sample handling and preparation, NMR/MS metabolomics data acquisition, processing, and spectral analyses) to computational (automation of spectral processing, univariate and multivariate statistical analysis, metabolite prediction and identification, multi-omics data integration, etc.) studies. Key scientific concepts of review: We provide a synopsis of our collective view regarding the use and reuse of metabolomics data and articulate several recommendations regarding best practices, which are aimed at encouraging researchers to strengthen efforts toward maximizing the utility of metabolomics data, multi-omics data integration, and enhancing the overall scientific impact of metabolomics studies. [ABSTRACT FROM AUTHOR]

In recent years, caffeic acid and its derivatives have received increasing attention due to their obvious physiological activities and wide distribution in nature. In this paper, to clarify the status of research on plant-derived caffeic acid and its derivatives, nuclear magnetic resonance spectroscopy data and possible biosynthetic pathways of these compounds were collected from scientific databases (SciFinder, PubMed and China Knowledge). According to different types of substituents, 17 caffeic acid and its derivatives can be divided into the following classes: caffeoyl ester derivatives, caffeyltartaric acid, caffeic acid amide derivatives, caffeoyl shikimic acid, caffeoyl quinic acid, caffeoyl danshens and caffeoyl glycoside. Generalization of their 13C-NMR and 1H-NMR data revealed that acylation with caffeic acid to form esters involves acylation shifts, which increase the chemical shift values of the corresponding carbons and decrease the chemical shift values of the corresponding carbons of caffeoyl. Once the hydroxyl group is ester, the hydrogen signal connected to the same carbon shifts to the low field (1.1~1.6). The biosynthetic pathways were summarized, and it was found that caffeic acid and its derivatives are first synthesized in plants through the shikimic acid pathway, in which phenylalanine is deaminated to cinnamic acid and then transformed into caffeic acid and its derivatives. The purpose of this review is to provide a reference for further research on the rapid structural identification and biofabrication of caffeic acid and its derivatives. [ABSTRACT FROM AUTHOR]

Recent studies have indicated that the injection of carbon dioxide (CO2) can lead to increased oil recovery in fractured shale reservoirs following natural depletion. Despite advancements in understanding mass exchange processes in subsurface formations, there remains a knowledge gap concerning the disparities in these processes between the matrix and fractures at the pore scale in formations with varying permeability. This study aims to experimentally investigate the CO2 diffusion behaviors and in situ oil recovery through a CO2 huff 'n' puff process in the Jimsar shale oil reservoir. To achieve this, we designed three matrix-fracture models with different permeabilities (0.074 mD, 0.170 mD, and 0.466 mD) and experimented at 30 MPa and 91 °C. The oil concentration in both the matrix and fracture was monitored using a low-field nuclear magnetic resonance (LF-NMR) technique to quantify in situ oil recovery and elucidate mass-exchange behaviors. The results showed that after three cycles of CO2 huff 'n' puff, the total recovery degree increased from 30.28% to 34.95% as the matrix permeability of the core samples increased from 0.074 to 0.466 mD, indicating a positive correlation between CO2 extraction efficiency and matrix permeability. Under similar fracture conditions, the increase in matrix permeability further promoted CO2 extraction efficiency during CO2 huff 'n' puff. Specifically, the increase in matrix permeability of the core had the greatest effect on the extraction of the first-cycle injection in large pores, which increased from 16.42% to 36.64%. The findings from our research provide valuable insights into the CO2 huff 'n' puff effects in different pore sizes following fracturing under varying permeability conditions, shedding light on the mechanisms of CO2-enhanced oil recovery in fractured shale oil reservoirs. [ABSTRACT FROM AUTHOR]

Many‐body expansion (MBE) fragment approaches have been applied to accurately compute nuclear magnetic resonance (NMR) parameters in crystalline systems. Recent examples demonstrate that electric field gradient (EFG) tensor parameters can be accurately calculated for 14N and 17O. A key additional development is the simple molecular correction (SMC) approach, which uses two one‐body fragment (i.e., isolated molecule) calculations to adjust NMR parameter values established using 'benchmark' projector augmented‐wave (PAW) density functional theory (DFT) values. Here, we apply a SMC using the hybrid PBE0 exchange‐correlation (XC) functional to see if this can improve the accuracy of calculated 35Cl EFG tensor parameters. We selected eight organic and two inorganic crystal structures and considered 15 chlorine sites. We find that this SMC improves the accuracy of computed values for both the 35Cl quadrupolar coupling constant (CQ) and the asymmetry parameter (ηQ) by approximately 30% compared with benchmark PAW DFT values. We also assessed a SMC that offers local improvements not only in terms of the quality of the XC functional but simultaneously in the quality of the description of relativistic effects via the inclusion of spin–orbit effects. As the inorganic systems considered contain heavy atoms bonded to the chlorine atoms, we find further improvements in the accuracy of calculated 35Cl EFG tensor parameters when both a hybrid functional and spin–orbit effects are included in the SMC. On the contrary, for chlorine‐containing organics, the inclusion of spin–orbit relativistic effects using a SMC does not improve the accuracy of computed 35Cl EFG tensor parameters. [ABSTRACT FROM AUTHOR]

With direct application to current and future consumer healthcare products, this research sheds light on the importance of packaging and its potential effects on both Active Pharmaceutical Ingredient (API) delivery and stability. Industrially sourced, proprietary experimental formulations (PEFs), specifically oral cleansers, based on salicylic acid and hydrogen peroxide, discolored over time at different rates, depending on packaging type used. This discoloration stemmed from an interplay of two factors, involving both spontaneous formulation degradation and the interaction of both degradants and salicylic acid with the internal surface of the packaging. This manuscript reports on the investigation to uncover the origins of discoloration. To investigate this real-world, industrial pipeline problem, we exploited the high dimensionality and simple sample preparation uniquely afforded by NMR. Using a combination of 1D/2D NMR and diffusion-ordered NMR spectroscopy (DOSY) to leverage molecular mass estimations from, we not only quickly confirmed the identities of these degradants, but also assessed their formation as a function of temperature and pH, providing insight into the mechanisms underlying their formation. We were able to identify catechol as the main source of discoloration over a period of several weeks, being formed at the ppm level. Furthermore, we evaluated the formulation–container interaction, employing NMR, ICP-MS, and ATR-IR. Despite this comprehensive analysis, the root causes of discoloration could only tentatively be assigned to a surface Ti complex of salicylic acid and other hydroxy carboxylic acids. Through the understanding of formulation degradation pathways, we were able to support further toxicology assessment, vital to both consumer safety and the manufacturer. This work underscores the invaluable role of NMR in the analysis of intricate proprietary mixtures with a consumer-centric purpose. Our findings demonstrate that conventional analytical techniques falter in the face of such complexity, requiring extensive preparation and pre-analytical processing, highlighting the novelty and crucial relevance of NMR research to manufacturers and consumers. Such an analysis is of value in the pursuit of materials within the consumer-healthcare space, which meet the requirements for successful recycling or re-use. [ABSTRACT FROM AUTHOR]

Two novel [ONO]-type tridentate Schiff base compounds namely (E)-2-(((2-hydroxyphenyl)imino) methyl)-4,5-dimethoxyphenol, C15H15NO4 (1), and (E)-2-(((5-chloro-2-hydroxyphenyl)imino)methyl)-4,5-dimethoxyphenol, C15H14ClNO4 (2) were synthesized. These compounds were characterized using various spectroscopic techniques, including single crystal X-ray diffraction (XRD), infrared (IR), proton nuclear magnetic resonance (1H NMR), carbon-13 nuclear magnetic resonance (13C NMR), and UV-Vis spectroscopy. The X-ray crystallographic analysis revealed that both compounds 1 and 2 contain two independent molecules within the asymmetric unit. Compound 1 crystallizes in the orthorhombic system with the Pna21 space group, while compound 2 crystallizes in the monoclinic system with the P21/c space group. An important feature observed in the crystal structure of compound 1 is the presence of O–H···N and O–H⋯O hydrogen bonds. In compound 2, the hydrogen bonding interactions involve C–H⋯O, O–H⋯O and O–H⋯N. Additionally, both compounds exhibit C–H⋯π interactions. To further understand the bonding interactions in compounds 1 and 2, Hirshfeld surface analyses and 2D fingerprint graphs were performed. The results indicate that the Hirshfeld surfaces are predominantly influenced by H⋯H, O⋯H, and C⋯H contacts. [ABSTRACT FROM AUTHOR]

p97/VCP is an essential AAA+ ATPase involved in diverse cellular activities by interacting with an array of protein adaptors that recruit p97 for specific tasks. p47 is one of the adaptors that targets p97 for membrane remodeling by forming a stable complex with p97 through multivalent interactions. Here, we report a pair of previously unidentified interactions between the N-terminal part of p47 (residues 1–94) and the N-terminal domain (NTD) of p97. Using nuclear magnetic resonance (NMR) spectroscopy, we identify two binding sites on p47, one located on the ubiquitin-associated (UBA) domain and the other on the intrinsically disordered linker, that interact with the same basic patch on p97 NTD, driven by electrostatic forces. Reciprocal NMR titration experiments between p47 (residues 1–94) and p97 NTD reveal that these interactions are relatively weak in nature with dissociation constants on the order of hundreds of micromolar to millimolar in trans. Structural models of the two interactions are developed based on NMR chemical shift perturbations, which reveal details of the tentative binding interfaces. Our findings provide new insights into the mechanism by which ubiquitinated substrates are delivered from p47 to p97 for unfolding. [ABSTRACT FROM AUTHOR]

A new method for the synthesis of reactive oligoimides with terminal nadic groups without the use of toxic reagents is proposed. The synthesis of ROI is carried out in dimethylacetamide (DMAA) in two stages without isolation of an intermediate product. Aromatic diamine is condensed in the first stage with the mixture of aromatic dianhydride and nadic anhydride at 25 °C to form oligoamidoacid. Thermochemical imidization of oligoamidoacid is carried out in the second stage in the presence of a cyclizing system of methyltriethoxysilane and diazobicyclooctane (MTEOS—DABCO) at 140 °C with the formation of oligoimides carrying terminal nadic groups. The structure of the final products was confirmed by 1H NMR and IR spectroscopy. Bis-amidoacid 2a was obtained as an example of a model compound by condensation of 2,2-bis(4-aminophenoxyphenyl)-propane and nadic anhydride (1: 2 mol) and the kinetics of imidization was investigated. It is demonstrated that the imidization reaction is significantly accelerated in the presence of the MTEOS + DABCO system compared to the reaction in the absence of additives. Almost complete conversion of carboxyamide groups into imide cycles is achieved in 30 min, while maintaining unsaturated bonds in the terminal groups. [ABSTRACT FROM AUTHOR]

The effects of bitter gourd seed oil (Momordica charantia) the storage stability of sunflower oil were examined in the present study. The effects of oxidation and those of the bitter gourd addition on the quality characteristics of the sunflower oils were determined by using classical and spectrophotometric methods during thermal oxidation. The changes of sunflower oil samples added with different concentrations (10 and 20 %) of bitter gourd seed oil were found in Raman and Fourier transform infrared spectroscopy and it was also observed that there was an increase due to secondary oxidation products forming during the storage. Furthermore, the oxidation of sunflower oils was comparatively examined by using nuclear magnetic resonance spectroscopy. As a result of both classical and spectrophotometric analyses, it was determined that the addition of 10 % bitter gourd seed oil enhanced the storage stability of sunflower oil. [ABSTRACT FROM AUTHOR]

Pore structure is a fundamental parameter in determining the hydrocarbon storage capacity and flow characteristics of a reservoir. Mercury injection capillary pressure (MICP) and nuclear magnetic resonance (NMR) are two commonly utilized techniques for characterizing rock pore structures. However, current studies indicate that disparities in testing methodologies due to distinct physical characteristics lead to a partial misalignment in pore size distributions. We conducted MICP (dynamic) and NMR (static) experiments on eight tight sandstone and eight shale samples and proposed a method to utilize information from the differences in MICP and NMR pore size distributions, aiming to enhance the accuracy of rock quality analysis. We observed that in rock cores where large pores are interconnected with smaller pore throats, MICP tends to overestimate the proportion of these smaller pores and underestimate the larger ones. Furthermore, we integrated information from both dynamic and static experimental processes based on physical significance and found that the fitting accuracy of the newly proposed method is superior to the Winland r35 equation. Compared to the Winland r35 equation, our new method significantly improves fitting accuracy, increasing the R-squared value from 0.46 to 0.93 in sandstones and from 0.80 to 0.87 in shales. This represents a potential high-precision, comprehensive tool for rock quality analysis, offering a new perspective for an in-depth understanding of rock properties. [ABSTRACT FROM AUTHOR]

Blood metabolite levels are affected by numerous factors, including preanalytical factors such as collection methods and geographical sites. These perturbations have caused deleterious consequences for many metabolomics studies and represent a major challenge in the metabolomics field. It is important to understand these factors and develop models to reduce their perturbations. However, to date, the lack of suitable mathematical models for blood metabolite levels under homeostasis has hindered progress. In this study, we develop quantitative models of blood metabolite levels in healthy adults based on multisite sample cohorts that mimic the current challenge. Five cohorts of samples obtained across four geographically distinct sites were investigated, focusing on approximately 50 metabolites that were quantified using 1H NMR spectroscopy. More than one-third of the variation in these metabolite profiles is due to cross-cohort variation. A dramatic reduction in the variation of metabolite levels (90%), especially their site-to-site variation (95%), was achieved by modeling each metabolite using demographic and clinical factors and especially other metabolites, as observed in the top principal components. The results also reveal that several metabolites contribute disproportionately to such variation, which could be explained by their association with biological pathways including biosynthesis and degradation. The study demonstrates an intriguing network effect of metabolites that can be utilized to better define homeostatic metabolite levels, which may have implications for improved health monitoring. As an example of the potential utility of the approach, we show that modeling gender-related metabolic differences retains the interesting variance while reducing unwanted (site-related) variance. [ABSTRACT FROM AUTHOR]

The proposed broadband attached proton test sequence allows the user to easily record 13C nuclear magnetic resonance multiplicity-edited and quaternary-carbon-only spectra. Compared to earlier attached proton test experiments, it preserves both a tolerance for wide ranges of one-bond-coupling constant values and the effective suppression of residual CHn signals in the quaternary-carbon-only spectra. The recording of edited spectra or quaternary-carbon-only spectra is made easy by a single, user-controllable constant. These attributes make the broadband attached proton test experiment attractive for the 13C analysis of small molecules, including spectral editing, particularly in high-throughput analysis laboratories. [ABSTRACT FROM AUTHOR]