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In the 1H NMR spectra (DMSO-d6) of 1,3-disubstituted ureas containing the 4,7,7-trimethyl-3-oxo-4-oxabicyclo[2.2.1]heptan-1-yl substituent, the signals for the CH2—CH2 moiety appear as an ADMP-type spin system consisting of four doublets of doublets of doublets with chemical shifts in the range from 1.54 to 2.80 ppm. The experiment in CD3OD showed the disappearance of the signal at δ 2.80 and a change in the multiplicity of the other signals, which is indicative of the selective deuterium exchange of one of the four protons of the CH2—CH2 group for a deuterium atom. This allows the selective modification of compounds containing the oxacamphanyl moiety. [ABSTRACT FROM AUTHOR]

Novel biologically active molecules have been isolated from the tunic biomass of marine ascidian fauna. In these findings, we evaluated the antimicrobial, antioxidant molecules of methanol and ethanol tissue extracts of tunic ascidians Phallusia nigra. In addition, these experiments along with FT-IR and 1H NMR analysis allowed us to identify the mainly composed active functional groups. The antimicrobial properties of crude extract of ascidians exhibited a zone of inhibition against all six pathogens. The best antimicrobial activity (29 ± 1.1 mm) was observed by the methanol extract of P. nigra toward Pseudomonas aeruginosa. Besides, the enriched antimicrobial potential was tested in 100 µl concentration of methanol and ethanol against all pathogens. In comparison to methanol extracts, ethanol extracts were more efficient in a higher antioxidant potential of 41.24 ± 2.16%. In the diphenyl picryl hydrazyl (DPPH) system, the strongest radical scavenging activity of 58.62 ± 2.62% was exhibited by the standard ascorbic acid when compared to the tested extracts. FT-IR spectrum indicates the presence of alcohol, phenol, alkanes, and carboxylic acid in functional groups. The 1H NMR spectrum designates the presence of phenol and amide group of derivatives. The results were found to be responsible for such excellent antimicrobial and antioxidant molecules with unidentified potential compounds. The non-toxic ascidian extractions is an authentic source for pharmacological applications especially utilized for human clinical trials, but much more attention is needed for this unique fauna, particularly on the Indian coast. [ABSTRACT FROM AUTHOR]

Objective: This study investigates the biological activities of Rhododendron arboreum Sm from the eastern Himalayas, addressing a literature gap on its properties. It explores the plant's phytochemical, antioxidant, and medicinal characteristics. Significance: Evaluating methanolic extracts of R. arboreum offers valuable insights into its bioactive potential. Comprehensive GC-MS analysis identified a diverse array of compounds, highlighting the plant's chemical composition. Methods: Methanolic leaf and flower extracts underwent sequential extraction and phytochemical profiling using column chromatography, TLC, and GC-MS analysis. Spectral studies aided compound identification, and antioxidant activity was assessed via spectrophotometric assays. Results: Column chromatography separated methanol leaf and flower extracts into 17 and 24 distinct fractions, respectively. TLC analysis showed specific Rf values for leaf (0.58, 0.65, 0.75, 0.8, 0.86, 0.9) and flower samples (0.91, 0.38, 0.48, 0.51, 0.56, 0.6, 0.65, 0.75, 0.85, 0.96). GC-MS analysis revealed a variety of organic functional groups, including aliphatic hydrocarbons, aromatic compounds, heterocyclic molecules, phenolic compounds, steroids, terpenoids, alcohols, esters, and other bioactive compounds. FTIR spectra identified functional groups such as hydroxyls, primary amines, alkanes, and alkynes. NMR data indicated a complex molecular composition with diverse proton environments. Leaf extracts demonstrated superior antioxidant activity compared to flower extracts in DPPH, ABTS, hydrogen peroxide scavenging, lipid peroxidation inhibition, and FRAP assays. Conclusion: The study identifies diverse phytochemicals in R.arboreum extracts and highlights their potential applications in pharmaceuticals, nutraceuticals, and functional foods, owing to the superior antioxidant activity of leaf extracts compared to flowers. [ABSTRACT FROM AUTHOR]

Multiheme cytochromes located in different compartments are crucial for extracellular electron transfer in the bacterium Geobacter sulfurreducens to drive important environmental processes and biotechnological applications. Recent studies have unveiled that for particular sets of electron terminal acceptors, discrete respiratory pathways selectively recruit specific cytochromes from both the inner and outer membranes. However, such specificity was not observed for the abundant periplasmic cytochromes, namely the triheme cytochrome family PpcA‐E. In this work, the distinctive NMR spectroscopic signatures of these proteins in different redox states were explored to monitor pairwise interactions and electron transfer reactions between each pair of cytochromes. The results showed that the five proteins interact transiently and can exchange electrons between each other revealing intra‐promiscuity within the members of this family. This discovery is discussed in the light of the establishment of an effective electron transfer network by this pool of cytochromes. This network is advantageous to the bacteria as it enables the maintenance of the functional working potential redox range within the cells. [ABSTRACT FROM AUTHOR]

For the first time, the mechanism of metal aluminum dissolution in NaF–ScF3 eutectic melts and the chemical interaction between the constituents of this mixture have been thoroughly studied by a combination of differential thermal analysis (DTA), high temperature and solid-state nuclear magnetic resonance (NMR), and X-ray diffraction (XRD) coupled with the molecular dynamic simulations. The formation of an insoluble Al3Sc alloy in molten (NaF–ScF3)eut system was proven, and the chemical mechanism of this aluminothermic Al3Sc alloy production was elucidated. Corresponding ex situ examinations bring to light the formation of NaScF4 and solid solution of Na3(Al,Sc)F6 in cooled bath. The molecular dynamics calculations of the bath allow us to construct the structural model and to predict viscosity, density and electrical conductivity of the reagent melt to help to optimize the conditions of the alloy synthesis. [ABSTRACT FROM AUTHOR]

The complex compound dithiocarbamate exhibits various biological activities, including anticancer, antibacterial, antifungal, and antioxidant properties. Dibutyl tin (IV) N-ethylbenzyl dithiocarbamate was synthesized to overview its structure and evaluate its antibacterial activity against Salmonella typhimurium ATCC 14028 and Propionibacterium acnes. This compound was synthesized via an in situ method by adding dibutyl tin (IV) dichloride, N-ethylbenzylamine, and carbon disulfide, forming a precipitate, which was then dried to yield a white powder. This powder can also be crystallized. The compound was characterized using FTIR, ¹H NMR and 13C NMR spectroscopy, along with antibacterial activity testing using the disc diffusion method. The FTIR analysis revealed characteristic absorption bands at 1111.00 cm-1 (C-N), 731.02 cm-1 (C-S), 2954.95 cm-1 (C-H), 1602.85 cm-1 (C=C), 360.69 cm-1 (Sn-S), and 567.07 cm-1 (Sn-C). The ¹H NMR spectrum showed chemical shifts at 0-3.8570 ppm (δ CH3), 5.0032-5.1472 ppm (δ N-CH2), and 7.2780-7.3607 ppm (δ C6H5). The 13C NMR spectrum displayed signals at 0-34.5610 ppm (δ CH3), 48.6398-56.9247 ppm (δ N-CH2), 127.6651-135.7665 ppm (δ C6H5), and 201.7568 ppm (δ CS2). The antibacterial activity of dibutyl tin (IV) N-ethylbenzyl dithiocarbamate was assessed, revealing inhibition zones against Salmonella typhi of 6.78 mm (100 ppm), 7.36 mm (120 ppm), and 7.76 mm (140 ppm), categorizing the activity as moderate. Against Propionibacterium acnes, inhibition zones were 1.8 mm (100 ppm), 1.88 mm (120 ppm), and 2.13 mm (140 ppm), categorizing the activity as weak. Based on these findings, it can be concluded that dibutyl tin (IV) N-ethylbenzyl dithiocarbamate can be synthesized to form an octahedral structure and exhibits antibacterial activity. However, it is not yet suitable for use as a new antibiotic. [ABSTRACT FROM AUTHOR]

Controlling the extent of water invasion in the reservoir and mitigating its detrimental effects on gas well production and natural gas recovery have long been a challenging task in the efficient development of strongly heterogeneous edge water gas reservoirs. To elucidate the edge water invasion mechanism of strongly heterogeneous carbonate gas reservoirs, this study investigates the pore throat characteristics and fluid mobility from both qualitative and quantitative aspects, leveraging natural core observations, cast thin sections, scanning electron microscopy (SEM), and nuclear magnetic resonance (NMR) tests with centrifuge experiments. A core-scale edge water invasion simulation experiment was conducted under online NMR monitoring to examine the dynamic gas production characteristics of the three types of reservoirs during the water invasion process and to elucidate the formation mechanism and distribution pattern of water-sealed gas. Research findings indicate that carbonate reservoirs typically exhibit a diverse range of pore types, including various types of fractures and cavities. Fractures significantly enhance reservoir connectivity, thereby increasing fluid mobility, but also lead to strong non-uniform water invasion. In contrast, cavities substantially improve the storage capacity of the reservoir and can retard the advancement of the water invasion front, thereby alleviating the adverse effects of water invasion. The ultimate recovery rates of fracture-type, cavity-type, and fracture-cavity cores in the water invasion simulation experiment were 29.81%, 64.87%, and 53.03%, respectively. Premature water breakthroughs in the reservoir can result in a large number of gases in matrix pores and even cavities being sealed by formation water, rendering them unrecoverable, which seriously impacts the gas recovery rate of the reservoir. [ABSTRACT FROM AUTHOR]

Fungal diseases cause substantial loss to agricultural crops, affecting both quantities and quality. Although several methods are used for preventing disease incidence, fungicides remain crucial for higher yields and better quality. But in the past, the efficacy of several fungicides has decreased due to increased cases of fungicide resistant. In our pursuit of new effective fungicides, we synthesised a series of twenty 2-Indazol-1-yl-chromen-4-one derivatives (6a- 6t). The characterization of synthesized compounds was performed by several spectroscopic methods including Infrared, Nuclear Magnetic Resonance (¹H and 13C) and HRMS. Out of 20 synthesised compounds, 19 (6b- 6t) were found to be novel. All synthesised indazolylchromones showed very good antifungal activity against Sclerotium rolfsii and Fusarium oxysporum. Among the tested compounds, 6t and 6f exhibited very good fungicidal activity against S. rolfsii with an ED50 of 10.10 mg L-1 and 16.18 mg L[sup -1], respectively. In case of Fusarium oxysporum compound 6f displayed good' activity with an ED50 value of 27.82 mg L-1. Molecular docking study was done to predict the binding sites of most active compounds, 6t and 6f with Cytochrome P450 14alpha -sterol demethylase (CYP51) enzyme using molsoft software. The acute toxicity predictions the of synthesized compounds for fish (LC50,96 Hr), daphnid (LC50, 48 Hr) and green algae (EC50, 96Hr) and the chronic toxicity predictions (ChV) were assessed using Ecological Structure Activity Relationship (ECOSAR) model. As per ECOSAR prediction, all the chemicals are inside AD and not missing predictions. [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]

The fat mass and obesity-associated fatso (FTO) protein is a member of the Alkb family of dioxygenases and catalyzes oxidative demethylation of N6-methyladenosine (m6A), N1-methyladenosine (m1A), 3-methylthymine (m3T), and 3-methyluracil (m3U) in single-stranded nucleic acids. It is well established that the catalytic activity of FTO proceeds via two coupled reactions. The first reaction involves decarboxylation of alpha-ketoglutarate (aKG) and formation of an oxyferryl species. In the second reaction, the oxyferryl intermediate oxidizes the methylated nucleic acid to reestablish Fe(II) and the canonical base. However, it remains unclear how binding of the nucleic acid activates the aKG decarboxylation reaction and why FTO demethylates different methyl modifications at different rates. Here, we investigate the interaction of FTO with 5-mer DNA oligos incorporating the m6A, m1A, or m3T modifications using solution NMR, molecular dynamics (MD) simulations, and enzymatic assays. We show that binding of the nucleic acid to FTO activates a two-state conformational equilibrium in the aKG cosubstrate that modulates the O2 accessibility of the Fe(II) catalyst. Notably, the substrates that provide better stabilization to the aKG conformation in which Fe(II) is exposed to O2 are demethylated more efficiently by FTO. These results indicate that i) binding of the methylated nucleic acid is required to expose the catalytic metal to O2 and activate the aKG decarboxylation reaction, and ii) the measured turnover of the demethylation reaction (which is an ensemble average over the entire sample) depends on the ability of the methylated base to favor the Fe(II) state accessible to O2. [ABSTRACT FROM AUTHOR]

Motivated by the culinary and ethnopharmacological use of Acmella oleracea (L.) R.K. Jansen, this study aimed to unveil new chemical compounds from its essential oil (EO). Acmella oleracea, known for its anesthetic and spicy properties, has been used in traditional medicine and cuisine, particularly in Northern Brazil. Through a detailed GC-MS analysis, 180 constituents were identified, including 12 tentatively identified long-chain α-keto esters of various acids. Additionally, 18 new esters were synthesized for structural verification. This research expands the known chemical diversity of A. oleracea EO, providing a basis for potential pharmacological applications. The identification of new natural products, including homologs and analogs of acmellonate, underscores the EO's rich chemical profile and its potential for novel bioproduct development. [ABSTRACT FROM AUTHOR]

Polypropylene is widely used in the automobile, paint, and consumer product industries and is not biodegradable. Recycling polypropylene is essential to maintaining sustainability. When the polypropylene as a 3D filament is used to print a component, wrapping issue is created. Therefore, fewer articles have been published. In this study, virgin and recycled polypropylene was reinforced with tamarind fruit shell power (TFSP) as a filler to make the 3D composite filament and solution for wrapping issue was sought. The crystallite size of TFSP was 39.7 nm, and its thermal constancy was 230 °C. It also had a great crystallinity index of 43.6%. The exterior morphology of TFSPs was studied using an atomic force microscope and a scanning electron microscope. The results of flexural and tensile tests conducted on composites made of virgin and recycled polypropylene reinforced with TFSP showed that 3 wt% reinforcement is the optimal mix to produce better characteristics. An impact testing, it was found that 1.5 wt% reinforcement produces better results. All of the aforementioned findings unequivocally demonstrated that recycled polypropylene, with a tolerance limit of 15%, can be used in place of virgin polypropylene. [ABSTRACT FROM AUTHOR]

Unconventional oil and gas resources are indispensable, and shale oil is one of them. The Junggar Basin is a typical superposition oil and gas basin in China, with reserves of 100 million tons in many areas and various types of oil and gas reservoirs. The Permian Fengcheng Formation in Mahu Sag has great potential for oil generation, making the study of the Fengcheng Formation reservoir in Mahu Sag particularly important. Based on previous studies, the core sample from well Maye-1 is divided into four lithologies according to mineral composition: felsic shale, dolomitic felsic shale, clay-bearing felsic shale, and siltstone interlayers. Through core observation and description, it is found that the macroscopic porosity of each lithology is well-developed, with felsic shale exhibiting the highest macroscopic fracture density, followed by siltstone interlayers, and clay-bearing felsic shale showing the least development. Argon ion polishing scanning electron microscopy (SEM) and nuclear magnetic resonance (NMR) techniques show that the siltstone interlayer pore development is the best, with pore sizes ranging from 100 to 4000 nm. The fracture development of dolomitic felsic shale is the most significant, with fractures contributing up to 80.14%. The porosity of clay-bearing felsic shale is only 1.12%. The development of pores and fractures in the study area is related to sedimentary tectonic factors and diagenesis. It mainly exhibits three types of subfacies deposits, namely semi-deep lake subfacies, shallow lake subfacies, and lakeshore lake subfacies, predominantly composed of felsic shale. Strong tectonic movements contribute to the formation of macroscopic fractures. Diagenesis plays a crucial role in the formation of microscopic pores. The Fengcheng Formation is primarily influenced by compaction, pressure dissolution, dissolution, and metasomatism. These various diagenetic processes collectively promote the formation of pores, ultimately leading to the development of a multi-scale porosity system in the Fengcheng Formation. [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]

Due to the deterioration caused by repeated freeze–thaw cycles, concrete materials in cold regions often develop cracks, which have serious effects and challenge the durability of concrete-based structures. Therefore, it is worthwhile to repair and strengthen freeze–thaw-damaged concrete to extend the service duration of the structure. In the present study, to investigate the restorative effect of surface reinforcer on freeze–thaw-deteriorated concrete specimens, the effects of the surface reinforcer type, its action duration, and the number of applications on the strength and deformation parameters of repaired specimens were systematically studied. Moreover, pore size distribution, pore structure at different depths, and the micromorphology characteristics were investigated by nuclear magnetic resonance (NMR), pore structure, and scanning electron microscope (SEM) tests to reveal the repair mechanism of different surface reinforcer types. The results indicated that the compressive strength of freeze–thaw-deteriorated concrete could be increased by up to 15.67% after the application of the surface reinforcer. Both the values of compressive strength and deformation modulus E50 increased with the increase in the action duration. In addition, the surface reinforcer could efficiently penetrate the interior of the deteriorated specimen and was able to decrease the total proportion of multi-harmful pores and harmful pores. Furthermore, the pore structure parameters could be significantly improved at a depth of 10 mm; however, the reparative effect of the surface reinforcer gradually decreased with the increase in the action depth. The surface reinforcer could efficiently promote the second hydration of cement and generate more cementitious materials to fill the microvoids, thereby improving the compactness and mechanical properties of the repaired specimens. [ABSTRACT FROM AUTHOR]

This study evaluated the potential of using combined relaxation (CRelax) spectra within time-domain nuclear magnetic resonance (TD-NMR) measurements to predict meat quality. Broiler fillets affected by different severities of the wooden breast (WB) conditions were used as case-study samples because of the broader ranges of meat-quality variations. Partial least squares regression (PLSR) models were established to predict water-holding capacity (WHC) and meat texture, demonstrating superior CRelax capabilities for predicting meat quality. Additionally, a partial least squares discriminant analysis (PLS-DA) model was developed to predict WB severity based on CRelax spectra. The models exhibited high accuracy in distinguishing normal fillets from those affected by the WB condition and demonstrated competitive performance in classifying WB severity. This research contributes innovative insights into advanced spectroscopic techniques for comprehensive meat-quality evaluation, with implications for enhancing precision in meat applications. [ABSTRACT FROM AUTHOR]

Kinetic inertness of Mn(II)‐based MRI contrast agents can be improved by increasing the rigidity of the polydentate ligand that tightly coordinate the metal ion. Taking inspiration from the remarkable increase in kinetic inertness of [Mn(CDTA)]2− compared to [Mn(EDTA)]2− due to the cyclohexyl backbone rigidity, we devised that bicyclic ligands would further improve the kinetic inertness of the Mn(II) complexes. The length of the alkyl bridge on the cyclohexane ring was varied from methylene (BCH‐DTA), ethylene (BCO‐DTA) to propylene (BCN‐DTA) to evaluate the influence of the different trans‐diaminotetraacetate ligands on relaxometric, thermodynamic and kinetic properties of the Mn(II) complexes. 1H and 17O NMR relaxometric studies showed a slight increase in relaxivity and a faster water exchange rate in these Mn(II)‐complexes with respect to [Mn(CDTA)]2−. Solution studies revealed that the conditional stability (pMn) and dissociation half‐life (t1/2) at pH 7.4 follow the order [Mn(BCH‐DTA)]2−<[Mn(BCO‐DTA)]2−<[Mn(BCN‐DTA)]2− highlighting the effect of the bridge length on the overall stability of the Mn(II) complexes. Remarkably, [Mn(BCN‐DTA)]2− shows an improved pMn value and a 7‐times higher kinetic inertness than [Mn(CDTA)]2−. NMR studies on the Zn(II) analogues confirm the rigidity of the bicyclic complexes with an isomerization process at >313 K for the smaller bridged complex [Zn(BCH‐DTA)]2−. [ABSTRACT FROM AUTHOR]

Unconsolidated sand reservoirs containing heavy oil play a significant role in hydrocarbon resources, characterized by high porosity and permeability alongside abundant movable fines. During production, these fines can detach and migrate with the reservoir fluids, causing pore plugging and reduced productivity. Visualizing and quantitatively evaluating the evolution of pore structure caused by fines migration under various influencing factors at the microscale is fundamental for devising effective prevention and mitigation measures. This study employs on-line NMR experiments and CFD-DEM simulations to investigate fines migration processes and their effects on physical properties and pore structure at the pore scale. Results indicate that fines migration initiates the formation of a preferential network of migration pathways. The evolution of pore structure demonstrates zonal characteristics along the flow direction, with fines plugging and residual accumulation primarily occurring in the middle/rear section of the core. As the core's skeleton porosity decreases, fines plugging intensifies; however, at high injection velocity, new dominant flow channels may emerge, leading to a transition from a single-peak to a double-peak T2 spectrum. Below the critical velocity (0.5-1 mL/min), an increase in flow velocity exacerbates severe fines plugging. Conversely, above the critical velocity, an increase in flow velocity results in a more pronounced enhancement of permeability. [ABSTRACT FROM AUTHOR]

Using the Polarizable Continuum Model (PCM), we investigated the solvent effect on the spectroscopic properties of three different groups of molecules with potential antitumor: three endocannabinoids—Anandamide, Met‐Anandamide, and Chloroethylamide; three phytocannabinoid—Cannabichromene, Cannabidiol and Cannabigerol—and two flavonoids—Morin and Quercetin. Our findings indicate increases in the dipole moment whereas the optical absorption spectrum shows a small effect of water on absorption peaks for all molecules, but with an impact on absorption intensity for some compounds. Our calculations indicated NMR shifts up to 7 ppm for carbon atoms and between 11 and 63 ppm for the oxygen ones. [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]

All‐solid‐state batteries relying on Li metal as negative electrode material and a ceramic electrolyte may severely suffer from unwanted interfacial processes. Here, Li1.3Al0.3Ti1.7(PO4)3 (LATP) serve as a model electrolyte which is known to form an ionic‐electronic, that is, mixed conducting interphase (MCI) when in contact with metallic Li or any other Li source. Li1.3+xAl0.3Ti1.7(PO4)3 with x = 0.2, 0.6 and 1.3 is prepared via ex situ chemical lithiation to mimic the formation of MCIs taking place otherwise operando. The preparation of large amounts of lithiated LATP with controlled Li contents allowed us to use nuclear and electric techniques to study local structures and ionic/electronic dynamics in detail. The results point to the formation of a core‐shell two‐phase morphology with the Li‐rich Li3Al0.3Ti1.7(PO4)3 phase covering the nonlithiated Li‐poor regions. The originally poor electronic conductivity σeon of 6.5 × 10−12 S cm−1 (293 K) increases by ≈3 orders of magnitude, hence reaching the order of 6.6 × 10−9 S cm−1 for x = 0.6. At even higher loadings (x = 1.3), a decrease in conductivity is seen, i.e., not exceeding alarming values for σeon. Quantifying electronic and ionic transport processes will help assessing the extent of damage through MCI formation and discussing whether any strategies to mitigate such formation is necessary at all. [ABSTRACT FROM AUTHOR]

Efficiently crushing deep hard rock remains a significant engineering challenge. As an innovative rock-breaking technique, laser technology shows considerable promise for applications in deep engineering. Analyzing the damage characteristics of rock after laser irradiation and clarifying the mechanism of laser rock-breaking are crucial for advancing this technology towards practical engineering applications. Taking basalt as a typical representative of deep hard rock, we introduced computed tomography (CT) scanning and nuclear magnetic resonance (NMR) technology to study the internal macro and micro pore characteristics of the rock after laser irradiation with different power. Additionally, we reconstructed the morphology of the laser-drilled holes. The results show that the surface temperature of the rock under laser irradiation generally follows a Gaussian distribution, and the penetration depth of the 1250 W laser can reach 41.51 mm after 30 seconds. Laser irradiation affects the microscopic pores of the rock, causing small pores to expand into larger ones as the laser power increases. After laser irradiation, the molten holes can be categorized into drum-shaped and V-shaped zones, and the timely discharge of molten material enhances the efficiency of laser rock-breaking. These findings provide theoretical and technical support for the application of laser rock-breaking technology in the efficient crushing of deep hard rock and resource extraction. [ABSTRACT FROM AUTHOR]

Solution nuclear magnetic resonance (NMR) analysis of polysaccharides can provide valuable information not only on their primary structures but also on their conformation, dynamics, and interactions under physiological conditions. One of the main problems is that non‐anomeric 1H signals typically overlap, and this often hinders detailed NMR analysis. Isotope enrichment, such as with 13C and 15N, will add a new dimension to the NMR spectra of polysaccharides, and spectral analysis can be performed with enhanced sensitivity using isolated peaks. For this purpose, here we have prepared uniformly 13C‐ and/or 15N‐labeled chondroitin polysaccharides –4)‐β‐D‐glucuronopyranosyl‐(1–3)‐2‐acetamido‐2‐deoxy‐β‐D‐galactopyranosyl‐(1– with molecular weights in the range from 310 to 460 k by bacterial fermentation. The enrichment ratios for 13C and 15N were 98.9 and 99.8%, respectively, based on the mass spectrometric analysis of the constituent chondroitin disaccharides. 1H and 13C NMR signals were assigned mainly based on HSQC and 13C‐detection experiments including INADEQUATE, HETCOR, and HETCOR‐TOCSY. The carbonyl carbon signal of the N‐acetyl‐β‐D‐galactosamine residue was unambiguously distinguished from the C6 carbon of the β‐D‐glucuronic acid residue by the observation of 13C peak splitting due to 1JCN coupling in 13C‐ and 15N‐labeled chondroitin. The T2* and T1 were measured and indicate that both rigid and mobile sites are present in the long sequence of chondroitin. The conformation, dynamics, and interactions of chondroitin and its derivatives will be further analyzed based on the results obtained in this study. [ABSTRACT FROM AUTHOR]

Despite the increasing interest in the development of novel metal-based compounds for cancer treatment, these molecules are currently poorly characterized in mechanistic terms, due to their multiple macromolecular targets inside the cells. In this review, we show how 1H NMR metabolomics provides a powerful tool to investigate the metabolic perturbations induced by metal-compounds in cells. The chemical identity and concentration of metabolites detected in cell lysates and their respective growth media by NMR can be viewed as a global fingerprint that describes the response to drug treatment. In this framework, the applications of NMR-based metabolomics to study cellular effects induced by the treatment of cells with anticancer metal-based compounds are comprehensively reviewed. [ABSTRACT FROM AUTHOR]

Introduction: Fighter pilots must support the effects of many stressors, including physical and psychological exertion, circadian disturbance, jet lag, and environmental stress. Despite the rigorous selection of military pilots, those factors predispose to failures in physiological compensatory mechanisms and metabolic flexibility. Objectives: We compared through NMR-based metabolomics the metabolic profile of Brazilian F5 fighter pilots with different flight experiences vs. the control group of non-pilots. We hypothesized that combat pilots have metabolic flexibility associated with combat flight time. Methods: We evaluated for the first time 34 Brazilian fighter pilots from Santa Cruz Air Base (Rio de Janeiro, RJ) allocated into three groups: pilots with lower total accumulated flight experience < 1,100 h (PC1, n = 7); pilots with higher total accumulated flight experience ≥ 1,100 h (PC2, n = 6); military non-pilots (CONT, n = 21). Data collection included anthropometric measurements, total blood count, lipidogram, markers of oxidative stress, and serum NMR-based metabolomics. Results: In comparison with controls (p < 0.05), pilots exhibited decreased levels of white blood cells (−13%), neutrophils (−15%), lymphocytes (−20%), alfa-glucose (−13%), lactate (−26%), glutamine (−11%), histidine (−20%), and tyrosine (−11%), but higher isobutyrate (+ 10%) concentrations. Significant correlations were found between lactate vs. amino acids in CONT (r = 0.55–0.68, p < 0.001), and vs. glutamine in PC2 (r = 0.94, p = 0.01). Conclusion: Fighter pilots with lower experience showed a dysregulation in immune-metabolic function in comparison with controls, which seemed to be counteracted by the accumulation of flight hours. Those findings might have implications for the health preservation and operational training of fighter pilots. [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]

Thiazolin-4-ones and their derivatives represent important heterocyclic scaffolds with various applications in medicinal chemistry. For that reason, the synthesis of two 5-substituted thiazolidin-4-one derivatives was performed. Their structure assignment was conducted by NMR experiments (2D-COSY, 2D-NOESY, 2D-HSQC and 2D-HMBC) and conformational analysis was conducted through Density Functional Theory calculations and 2D-NOESY. Conformational analysis showed that these two molecules adopt exo conformation. Their global minimum structures have two double bonds (C=N, C=C) in Z conformation and the third double (C=N) in E. Our DFT results are in agreement with the 2D-NMR measurements. Furthermore, the reaction isomerization paths were studied via DFT to check the stability of the conformers. Finally, some potential targets were found through the SwissADME platform and docking experiments were performed. Both compounds bind strongly to five macromolecules (triazoloquinazolines, mglur3, Jak3, Danio rerio HDAC6 CD2, acetylcholinesterase) and via SwissADME it was found that these two molecules obey Lipinski's Rule of Five. [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]

Overactivation of the epidermal growth factor receptor (EGFR) is critical for the development of multiple cancers. Previous studies have shown that the cell membrane is a key regulator of EGFR kinase activity through its interaction with the EGFR juxtamembrane domain (JM). However, the lipid recognition specificity of EGFR‐JM and its interaction details remain unclear. Using lipid strip and liposome pulldown assays, we showed that EGFR‐JM could specifically interact with PI(4,5)P2‐or phosphatidylserine‐containing membranes. We further characterized the JM–membrane interaction using NMR‐titration‐based chemical shift perturbation and paramagnetic relaxation enhancement analyses, and found that residues I649 − L659 comprised the membrane‐binding site. Furthermore, the membrane‐binding region contains the predicted dimerization motif of JM, 655LRRLL659, suggesting that membrane binding may affect JM dimerization and, therefore, regulate kinase activation. [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]

The hydroxypropyl chitosan (HPCH) and hydroxyethyl chitosan (HECH) are multifunctional chitosan derivatives with biocompatible and biodegradable properties. Due to their hydroxypropyl and hydroxethyl groups, they have water solubility, moisture retention, and gelling properties. In this study, the chitosan derivatives HPCH and HECH were obtained in two steps alkalisation and etherification. For alkalisation, chitosan was kept in an alkaline medium at -18C for 7 days. For etherification; the reaction was carried out for 48 hours by mixing alkaline chitosan with propylene oxide and ethylene oxide separately in a pressure reactor. The structures of the obtained HPCH and HECH were characterised by FT-IR, 1H(13C)-NMR, XRD, and TG analysis methods. Since the degree of deacetylation (DA) of chitosan is 75-85%, the chitosan units contain N-acetyl (-N-(CO)-CH3)) groups in addition to NH2 functional groups. When the 1H(13C)-NMR spectrum of chitosan was examined, the peak value of these acetyl groups was observed at δ1.89 ppm. When the XRD spectra were examined, it was observed that the strong peak in chitosan at 2θ-20° was weakened in HPCH and HECH. In addition, the thermal stability of HPCH and HECH was found to be higher than chitosan in TG analysis. [ABSTRACT FROM AUTHOR]

Agroindustrial potato (Solanum tuberosum L.) waste mainly includes peel and pulp; however, potatoes of low industrial quality are also discarded by industry. A viable alternative to give added value to these byproducts is the use of these as seeds, as well as the use of starch. The objective of this work was to evaluate the physiological quality (germination and vigor), starch content and relationship between these variables in discarded tubers from the industry through chemical-structural analyses to better understand their influence on starch composition. The physiological quality of the potatoes was evaluated through germination and vigor tests; likewise, starch was extracted, and the yield was determined. Physicochemical characterization of the starches was carried out through proximal and structural analysis using nuclear magnetic resonance (NMR). The results showed that the tubers had 100.00% germination and 98.66% vigor and were suitable for use as seeds. The starch yield did not significantly differ. However, characterization of the starch revealed significant differences (p = 0.05) in moisture, ash, carbohydrate and amylose contents, which were influenced by the storage temperature (4 °C) of the tubers subjected to a vigor test, which interferes with enzymatic activity. During germination, the NMR results showed type B crystallinity, which is typical of tubers, indicating that the viability tests did not promote changes in the type of crystallinity. The results obtained can help us understand the effect of germination on the composition of starch and, accordingly, choose the most appropriate applications for this starch, whether food or nonfood. [ABSTRACT FROM AUTHOR]

Context: Bismuth complexes with dithiocarbamate ligands have attracted attention because of their biological applications, such as antimicrobial, antileishmanial, and anticancer properties. These complexes have high cytotoxic activity against cancer cells, being more active than the standard drugs cisplatin, doxorubicin, and tamoxifen. In the present study, we investigated the ability of some DFT methods to reproduce the geometries and NMR spectra of the Bi(III) dithiocarbamate complexes, selected based on their proven antitumor activity. Our investigation revealed that the M06-L/def2-TZVP/ECP/CPCM method presented good accuracy in predicting geometries, while the TPSSh/def2-SVP/ECP/CPCM method proved effective in analyzing the 13C NMR spectra of these molecules. In general, all examined methods exhibited comparable performance in predicting 1H NMR signals. Methods: Calculations were performed with the Gaussian 09 program using the def2-SVP and def2-TZVP basis sets, employing relativistic effective core potential (ECP) for Bi and using the CPCM solvent model. The exchange–correlation functionals BP86, PBE, OLYP, M06-L, B3LYP, B3LYP-D3, M06-2X, TPSSh, CAM-B3LYP, and ωB97XD were used in the study. Geometry optimizations were started from crystallographic structures available at the Cambridge Structural Database. The theoretical results were compared with experimental data using the mean root-mean-square deviation (RMSD), mean absolute deviations (MAD), and linear correlation coefficient (R2). [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]

In medicinal chemistry, the precise configuration of molecules is a crucial determinant of their pharmacological properties. Hence, the introduction of a new chiral center during the synthetic pathway involves the assignment of configuration. Herein we assign, by means of molecular modeling 1H and 2D Nuclear Overhauser Effect NMR techniques, the configuration of the two diastereomers 2S-(1R-benzyloxy-hex-5-enyl)-2,3-dihydro-1,4-benzodioxine and 2S-(1S-benzyloxy-hex-5-enyl)-2,3-dihydro-1,4-benzodioxine, which are useful to synthetize analogs of the potent and highly selective dipeptidyl peptidase IV and carbonic anhydrase inhibitor recently published. [ABSTRACT FROM AUTHOR]

Hymenaea martiana Hayne's bark and resin are widely used in folk medicine for the treatment of various diseases, however the indiscriminate extractivism of its barks brings damage to its metabolism and development. In view this, the discovery of ways for a more rational use of the species becomes relevant. This study aims to evaluate possible similarities in chemical composition profile of different parts from H. martiana (barks, stalks and leaves) through the fingerprint by ¹H-NMR and FT-IR techniques. The principal component analysis (PCA) showed metabolic similarities between the barks and stalks in two spectroscopic techniques used. The similarity is explained by presence of sucrose and pinitol in both segments as main compounds of segments. The antioxidant activity profile, showed similarity corroborating thus, with observed in metabolic analysis, where IC 50 values showed no statistical difference between the barks (10.73 ± 0.12 µg.mL−1) and stalks (8.40 ± 0.58 µg.mL−1). In our results, the PCA showed a difference in the leaves fingerprint of one specimen collected. As pointed also by PCA analysis, this individual was over stress situation which promoted the biosynthesis of monoterpene linalool, a compound with defensor properties from plants. Furthermore, the similarities between the barks and stalks observed may be an indication of similar biological activity and may direct other studies in order to reduce the extraction of the barks and minimize the damage to the species. [Display omitted] • Hymenaea martiana Hayne's bark and resin are widely used in folk medicine for the treatment of various diseases. • Indiscriminate extractivism of its barks can bring damage to its metabolism and development. • The principal component analysis (PCA) showed metabolic similarities between barks and stems through FTIR and NMR experiments. • the chemical similarity found between bark and stems extends to the investigated antioxidant activity. [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]

ModA is a soluble periplasmic molybdate-binding protein found in most gram-negative bacteria. It is part of the ABC transporter complex ModABC that moves molybdenum into the cytoplasm, to be used by enzymes that carry out various redox reactions. Since there is no clear analog for ModA in humans, this protein could be a good target for antibacterial drug design. Backbone 1H, 13C and 15N chemical shifts of apo and molybdate-bound ModA from E. coli were assigned at pHs 6.0 and 4.5. In addition, side chain atoms were assigned for apo ModA at pH 6.0. When comparing apo and molybdate-bound ModA at pH 6.0, large chemical shift perturbations are observed, not only in areas near the bound metal, but also in regions that are distant from the metal-binding site. Given the significant conformational change between apo and holo ModA, we might expect the large chemical shift changes to be more widespread; however, since they are limited to specific regions, the residues with large perturbations may reveal allosteric sites that could ultimately be important for the design of antibiotics that target ModA. [ABSTRACT FROM AUTHOR]

Human small EDRK-rich factor protein SERF2 is a cellular driver of protein amyloid formation, a process that has been linked to neurodegenerative diseases including Alzheimer's and Parkinson's disease. SERF2 is a 59 amino acid protein, highly charged, and well conserved whose structure and physiological function is unclear. SERF family proteins including human SERF2 have shown a tendency to form fuzzy complexes with misfolded proteins such as α-Synuclein which has been linked to Parkinson's disease. SERF family proteins have been recently identified to bind nucleic acids, but the binding mechanism(s) remain enigmatic. Here, using multidimensional solution NMR, we report the 1H, 15N, and 13C chemical shift assignments (~ 86% of backbone resonance assignments) for human SERF2. TALOS-N predicted secondary structure of SERF2 showed three very short helices (3–4 residues long) in the N-terminal region of the protein and a long helix in the C-terminal region spanning residues 37–46 which is consistent with the helical content indicated by circular dichroism spectroscopy. Paramagnetic relaxation enhancement NMR analysis revealed that a short C-terminal region E53-K55 is in the proximity of the N-terminus. Having the backbone assignment of SERF2 allowed us to probe its interaction with α-Synuclein and to identify the residues in SERF2 binding interfaces that likely promote α-Synuclein aggregation. [ABSTRACT FROM AUTHOR]

Monoclonal antibodies (mAbs) are biotherapeutics that have achieved outstanding success in treating many life-threatening and chronic diseases. The recognition of an antigen is mediated by the fragment antigen binding (Fab) regions composed by four different disulfide bridge-linked immunoglobulin domains. NMR is a powerful method to assess the integrity, the structure and interaction of Fabs, but site specific analysis has been so far hampered by the size of the Fabs and the lack of approaches to produce isotopically labeled samples. We proposed here an efficient in vitro method to produce [15N, 13C, 2H]-labeled Fabs enabling high resolution NMR investigations of these powerful therapeutics. As an open system, the cell-free expression mode enables fine-tuned control of the redox potential in presence of disulfide bond isomerase to enhance the formation of native disulfide bonds. Moreover, inhibition of transaminases in the S30 cell-free extract offers the opportunity to produce perdeuterated Fab samples directly in 1H2O medium, without the need for a time-consuming and inefficient refolding process. This specific protocol was applied to produce an optimally labeled sample of a therapeutic Fab, enabling the sequential assignment of 1HN, 15N, 13C′, 13Cα, 13Cβ resonances of a full-length Fab. 90% of the backbone resonances of a Fab domain directed against the human LAMP1 glycoprotein were assigned successfully, opening new opportunities to study, at atomic resolution, Fabs' higher order structures, dynamics and interactions, using solution-state NMR. [ABSTRACT FROM AUTHOR]

A glucosyl-rich pectin, JMMP-3 (Mw, 2.572 × 104 g/mol, O-methyl % = 3.62%), was isolated and purified from the pericarp of the immature fruit of Juglans mandshurica Maxim. (QingLongYi). The structure of JMMP-3 was studied systematically by infrared spectroscopy, monosaccharide compositions, methylation analysis, partial acid hydrolysis, and 1/2D-NMR. The backbone of JMMP-3 possessed a smooth region (→ 4GalA1 →) and a hairy region (→ 4GalA1 → 2Rha1 →) with a molar ratio of 2: 5. The substitution of four characteristic side chains (R1-R4) occurs at C-4 of → 2,4)-α-Rhap-(1→, where R1 is composed of → 5)-α-Araf-(1→, R2 is composed of → 4)-β-Galp-(1 → and β-Galp-(1→, R3 is composed of α-Glcp-(1→, →4)-α-Glcp-(1 → and → 4,6)-α-Glcp-(1→, and R4 is composed of → 5)-α-Araf-(1→, β-Galp-(1→, → 4)-β-Galp-(1→, → 3,4)-β-Galp-(1→, → 4,6)-β-Galp-(1 → and → 2,4)-β-Galp-(1 →. In addition, the antitumor activity of JMMP-3 on HepG2 cells was preliminarily investigated. [ABSTRACT FROM AUTHOR]

PHPT1 is a histidine phosphatase that modulates signaling in eukaryotes through its catalytic activity. Here, we present an analysis of the structure and dynamics of PHPT1 through a combination of solution NMR, molecular dynamics, and biochemical experiments. We identify a salt bridge formed between the R78 guanidinium moiety and the C‐terminal carboxyl group on Y125 that is critical for ligand binding. Disruption of the salt bridge by appending a glycine residue at the C‐terminus (G126) leads to a decrease in catalytic activity and binding affinity for the pseudo substrate, para‐nitrophenylphosphate (pNPP), as well as the active site inhibitor, phenylphosphonic acid (PPA). We show through NMR chemical shift, 15N relaxation measurements, and analysis of molecular dynamics trajectories, that removal of this salt bridge results in an active site that is altered both structurally and dynamically thereby significantly impacting enzymatic function and confirming the importance of this electrostatic interaction. [ABSTRACT FROM AUTHOR]

Bacteria that have acquired resistance to most antibiotics, particularly those causing nosocomial infections, create serious problems. Among these, the emergence of vancomycin‐resistant enterococci was a tremendous shock, considering that vancomycin is the last resort for controlling methicillin‐resistant Staphylococcus aureus. Therefore, there is an urgent need to develop an inhibitor of VanX, a protein involved in vancomycin resistance. Although the crystal structure of VanX has been resolved, its asymmetric unit contains six molecules aligned in a row. We have developed a structural model of VanX as a stable dimer in solution, primarily utilizing nuclear magnetic resonance (NMR) residual dipolar coupling. Despite the 46 kDa molecular mass of the dimer, the analyses, which are typically not as straightforward as those of small proteins around 10 kDa, were successfully conducted. We assigned the main chain using an amino acid‐selective unlabeling method. Because we found that the zinc ion‐coordinating active sites in the dimer structure were situated in the opposite direction to the dimer interface, we generated an active monomer by replacing an amino acid at the dimer interface. The monomer consists of only 202 amino acids and is expected to be used in future studies to screen and improve inhibitors using NMR. [ABSTRACT FROM AUTHOR]

Controlling the liquid transport within cellulose-based materials is crucial for numerous applications, including printing, bio-assays, packaging, and cleaning. To control liquid transport and quality, post-processes such as calendering, a way of compressing and smoothen the paper using hard pressure rollers, and hydrophobisation, are commonly employed. To understand how these processes influence liquid uptake, this study uses an Ultra-Fast Imaging (UFI) NMR method to analyse moisture profiles during liquid uptake in various cellulose-based paper sheets with diverse levels of hydrophobisation and calendering. It is demonstrated that calendering decreases penetration speed and increases swelling. The reduction in penetration speed could be linked to a decrease in permeability upon calendering, as measured by the Gurley air permeance. Additionally, it is observed that hydrophobisation delayed and slowed down liquid uptake in the paper samples, and, in extreme cases, completely altered the liquid uptake phenomena. With substantial hydrophobisation, liquid penetration no longer proceeded with a well-defined liquid front but exhibited huge levels of fingering. Furthermore, is was observed that within highly hydrophobised paper, fibres were first prewetted, initiating a first swelling, before the pores between fibres could be filled. Subsequently, water could enter the pores between, allowing fibre bonds to be broken, leading to a second swelling of the paper sheet. The improved understanding will contribute to better control of the flow within cellulose-based materials, benefiting applications such as printing, packaging and microfluidics. [ABSTRACT FROM AUTHOR]

Lysergic acid diethylamide (LSD) is a hallucinogenic compound that binds to and activates the serotonin 2A receptor and is classified as a controlled narcotic in Japan. Recently, MiPLA, an N‐methyl‐N‐isopropyl derivative of LSD, has been detected in paper‐sheet products in several countries. This study focuses on the synthesis of MiPLA and includes a comprehensive analysis involving structural and liquid chromatography–mass spectrometry (LC‐MS). Particularly, MiPLA was synthesized in three‐steps starting from ergometrine maleate, which resulted in the formation of (8S)‐isomer, iso‐MiPLA, as a by‐product. The LC‐MS results showed that LSD, MiPLA, and iso‐MiPLA exhibited different retention times. Their chemical structures were determined using nuclear magnetic resonance spectroscopy, which revealed the presence of rotamers involving the N‐methyl‐N‐isopropyl groups of tertiary amides in MiPLA and iso‐MiPLA. [ABSTRACT FROM AUTHOR]

Biodiesel made from renewable energy sources is gaining popularity due to its environmental and economic benefits. In this work, the effect of the most important reaction variables was investigated during the acid‐catalyzed of Spirulina sp. microalgae oil to biodiesel. Results showed that the biodiesel was obtained at 60°C for 8 h using 30 g of dry Spirulina sp. powder in 300 mL of n‐hexane. Physical characteristics of the biodiesel produced from Spirulina sp. were confirmed using, evaporation temperature, flash point, freeze point, and fire point. The presence of bonds of CH3, ROH, RC≡C‐H, ‐CH = CH‐CH2)n, R‐CH2‐X, and ArOH in the biodiesel 1H NMR spectrum. Further, the biodiesel produced from the Spirulina sp. subjected to FT‐IR and GC MS which revealed the aliphatic hydrocarbons and the list of compounds such as Oleic acid, 9‐octadecenal etc. [ABSTRACT FROM AUTHOR]

This study demonstrates the synthesis of five novel quaternary ammonium aldimines through a two-step synthetic route involving a condensation reaction between 4-pyridincarboxyaldehyde and 3,4,5-trimethoxyaniline, followed by the quaternization of the pyridine N-atom with various aromatic α-bromo ketones. The newly obtained compounds underwent characterization for both purity and molecular structure, utilizing HR-MS, 1D, and 2D NMR spectroscopy in solution, as well as a comparison between single-crystal and powder X-ray analyses in a solid state. The thermal behavior of the studied compounds was evaluated using differential scanning calorimetry (DSC). The antioxidant properties of the compounds were assessed through DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging and ferric-reducing antioxidant power (FRAP) assays, employing Trolox as a standard. The performed in vitro antibacterial screening indicates a selective antibacterial activity against Gram-negative K. pneumoniae and P. aeruginosa, while no such activity is detected for Gram-negative E. coli and Gram-positive S. aureus. [ABSTRACT FROM AUTHOR]