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Traditionally, the stuffing model has been used to describe stress generation in chemically strengthened glass. Nevertheless, the associated unrealistic conditions, including an imaginary volume expansion and its suppression in an adiabatic closed system, inhibit a thorough understanding of the process. In this study, we propose a thermodynamic model in an isothermal open system to enable ion exchange without an imaginary volume expansion. We derive a fundamental equation and verify it using atomistic images obtained by Raman spectroscopy and nuclear magnetic resonance. This study paves the way for further atomistic design and development of strengthened glasses. [ABSTRACT FROM AUTHOR]

This article presents the application of continuous Floquet theory in solid-state nuclear magnetic resonance (NMR). Continuous Floquet theory extends the traditional Floquet theory to non-continuous Hamiltonians, enabling the description of observable effects not fully captured by the traditional Floquet theory due to its requirement for a periodic Hamiltonian. We present closed-form expressions for computing first- and second-order effective Hamiltonians, streamlining integration with the traditional Floquet theory and facilitating application in NMR experiments featuring multiple modulation frequencies. Subsequently, we show examples of the practical application of continuous Floquet theory by investigating several solid-state NMR experiments. These examples illustrate the importance of the duration of the pulse scheme regarding the width of the resonance conditions and the near-resonance behavior. [ABSTRACT FROM AUTHOR]

This study explored the interplay between the ligand–surface chemistry of colloidal CsPbBr3 nanowires (NWs) and their optical properties. The ligand equilibrium was probed using nuclear magnetic resonance spectroscopy, and by perturbing the equilibrium via dilution, the gradual removal of ligands from the CsPbBr3 surface was observed. This removal was correlated with an increase in the surface defect density, as suggested by a broadening of the photoluminescence (PL) spectrum, a decrease in the PL quantum yield (PLQY), and quenching of the PL decay. These results highlight similar surface binding between the traditional CsPbBr3 quantum dots and our NWs, thereby expanding the scope of well-established ligand chemistry to a relatively unexplored nanocrystal morphology. By controlling the dilution factor, it was revealed that CsPbBr3 NWs achieve a PLQY of 72% ± 2% and a relatively long average PL lifetime of 400 ± 10 ns, without relying on additional surface passivation techniques, such as ligand exchange. [ABSTRACT FROM AUTHOR]

A new algorithm has been developed to simulate two-dimensional (2D) spectra with correlated anisotropic frequencies faster and more accurately than previous methods. The technique uses finite-element numerical integration on the sphere and an interpolation scheme based on the Alderman–Solum–Grant algorithm. This method is particularly useful for numerical calculations of joint probability distribution functions involving quantities with a parametric orientation dependence. The technique's efficiency also allows for practical least-squares fitting of experimental 2D solid-state nuclear magnetic resonance (NMR) datasets. The simulation method is illustrated for select 2D NMR methods, and a least-squares analysis is demonstrated in the extraction of paramagnetic shift and quadrupolar coupling tensors and their relative orientation from the experimental shifting-d echo 2H NMR spectrum of a NiCl2 · 2D2O salt. [ABSTRACT FROM AUTHOR]

The effect of replacing magnesia by alumina on the pressure-dependent structure of amorphous enstatite was investigated by applying in situ high-pressure neutron diffraction with magnesium isotope substitution to glassy (MgO)0.375(Al2O3)0.125(SiO2)0.5. The replacement leads to a factor of 2.4 increase in the rate-of-change of the Mg–O coordination number with pressure, which increases from 4.76(4) at ambient pressure to 6.51(4) at 8.2 GPa, and accompanies a larger probability of magnesium finding bridging oxygen atoms as nearest-neighbors. The Al–O coordination number increases from 4.17(7) to 5.24(8) over the same pressure interval at a rate that increases when the pressure is above ∼3.5 GPa. On recovering the glass to ambient conditions, the Mg–O and Al–O coordination numbers reduce to 5.32(4) and 4.42(6), respectively. The Al–O value is in accordance with the results from solid-state 27Al nuclear magnetic resonance spectroscopy, which show the presence of six-coordinated aluminum species that are absent in the uncompressed material. These findings explain the appearance of distinct pressure-dependent structural transformation regimes in the preparation of permanently densified magnesium aluminosilicate glasses. They also indicate an anomalous minimum in the pressure dependence of the bulk modulus with an onset that suggests a pressure-dependent threshold for transitioning between scratch-resistant and crack-resistant material properties. [ABSTRACT FROM AUTHOR]

Traditional theories of the nuclear magnetic resonance (NMR) autocorrelation function for intra-molecular dipole pairs assume a single-exponential decay, yet the calculated autocorrelation of realistic systems displays a rich, multi-exponential behavior, resulting in anomalous NMR relaxation dispersion (i.e., frequency dependence). We develop an approach to model and interpret the multi-exponential intra-molecular autocorrelation using simple, physical models within a rigorous statistical mechanical development that encompasses both rotational diffusion and translational diffusion in the same framework. We recast the problem of evaluating the autocorrelation in terms of averaging over a diffusion propagator whose evolution is described by a Fokker–Planck equation. The time-independent part admits an eigenfunction expansion, allowing us to write the propagator as a sum over modes. Each mode has a spatial part that depends on the specified eigenfunction and a temporal part that depends on the corresponding eigenvalue (i.e., correlation time) with a simple, exponential decay. The spatial part is a probability distribution of the dipole pair, analogous to the stationary states of a quantum harmonic oscillator. Drawing inspiration from the idea of inherent structures in liquids, we interpret each of the spatial contributions as a specific molecular mode. These modes can be used to model and predict the NMR dipole–dipole relaxation dispersion of fluids by incorporating phenomena on the molecular level. We validate our statistical mechanical description of the distribution in molecular modes with molecular dynamics simulations interpreted without any relaxation models or adjustable parameters: the most important poles in the Padé–Laplace transform of the simulated autocorrelation agree with the eigenvalues predicted by the theory. [ABSTRACT FROM AUTHOR]

Despite the importance of rhodium complexes in catalysis, and the favorable 100% natural abundance of the spin-1/2 103Rh nucleus, there are few reports of 103Rh nuclear magnetic resonance (NMR) parameters in the literature. In part, this is the consequence of the very low gyromagnetic ratio of 103Rh and its dismal NMR sensitivity. In a previous paper [Harbor-Collins et al., J. Chem. Phys. 159, 104 307 (2023)], we demonstrated an NMR methodology for 1H-enhanced 103Rh NMR and demonstrated an application to the 103Rh NMR of the dirhodium formate paddlewheel complex. In this paper, we employ selective 18O labeling to break the magnetic equivalence of the 103Rh spin pair of dirhodium formate. This allows the estimation of the 103Rh–103Rh spin–spin coupling and provides access to the 103Rh singlet state. We present the first measurement of a 18O-induced 103Rh secondary isotope shift as well as the first instance of singlet order generated in a 103Rh spin pair. The field-dependence of 103Rh singlet relaxation is measured by field-cycling NMR experiments. [ABSTRACT FROM AUTHOR]

Nuclear spin hyperpolarization derived from parahydrogen is a technique for enhancing nuclear magnetic resonance (NMR) sensitivity. The key to hyperpolarization experiments is to achieve rapid transfer and detection to minimize relaxation losses, while also avoiding bubbles or turbulence to guarantee high spectral resolution. In this article, we describe an experimental approach for the interleaved joint modulation of parahydrogen-induced polarization and NMR. We provide schematic diagrams of parahydrogen-based polarizer with in situ high-pressure detection capability and low-field polarization transfer. This approach can help to control the experimental process and acquire experimental information, one example of which is the attainment of the highest hyperpolarization signal intensity at 3.6 s after closing the valve. The polarizer demonstrates in situ detection capability, allowing sample to be restabilized within 0.3 ± 0.1 s and high-resolution NMR sampling under a pressure of 3 bars. Moreover, it can transfer polarized samples from the polarization transfer field to the detection region of NMR within 1 ± 0.3 s for completing signal amplification by reversible exchange experiments. [ABSTRACT FROM AUTHOR]

We present a gauge-origin invariant exact two-component (X2C) approach within a modern density functional framework, supporting meta-generalized gradient approximations such as TPSS and range-separated hybrid functionals such as CAM-B3LYP. The complete exchange-correlation kernel is applied, including the direct contribution of the field-dependent basis functions and the reorthonormalization contribution from the perturbed overlap matrix. Additionally, the finite nucleus model is available for the electron-nucleus potential and the vector potential throughout. Efficiency is ensured by the diagonal local approximation to the unitary decoupling transformation in X2C as well as the (multipole-accelerated) resolution of the identity approximation for the Coulomb term (MARI-J, RI-J) and the seminumerical exchange approximation. Errors introduced by these approximations are assessed and found to be clearly negligible. The applicability of our implementation to large-scale calculations is demonstrated for a tin pincer-type system as well as low-valent tin and lead complexes. Here, the calculation of the Sn nuclear magnetic resonance shifts for the pincer-type ligand with about 2400 basis functions requires less than 1 h for hybrid density functionals. Further, the impact of spin–orbit coupling on the nucleus-independent chemical shifts and the corresponding ring currents of all-metal aromatic systems is studied. [ABSTRACT FROM AUTHOR]

We report measurements of the Meissner screening profile in a Nb (300 nm)/ Al 2 O 3 thin film using 8 Li β -detected nuclear magnetic resonance (β -NMR). The NMR probe 8 Li was ion-implanted into the Nb film at energies ≤ 20 keV, corresponding to mean stopping depths comparable to Nb 's magnetic penetration depth λ. 8 Li 's strong dipole–dipole coupling with the host 93 Nb nuclei provided a "cross-relaxation" channel that dominated in low magnetic fields, which conferred indirect sensitivity to the local magnetic field via the spin-lattice relaxation (SLR) rate 1 / T 1. From a fit of the 1 / T 1 data to a model accounting for its dependence on temperature, magnetic field, and 8 Li + implantation energy, we obtained a magnetic penetration depth λ 0 = 51.5(22) nm, consistent with a relatively short carrier mean-free-path ℓ = 18.7(29) nm typical of similarly prepared Nb films. The results presented here constitute an important step toward using 8 Li β -NMR to characterize bulk Nb samples with engineered surfaces, which are often used in the fabrication of particle accelerators. [ABSTRACT FROM AUTHOR]

In hyperpolarization experiments using parahydrogen, a partially negative line (PNL) of o-H2 is occasionally spotted in the nuclear magnetic resonance (NMR) spectra. This is a manifestation of the two-spin order (TSO) of the proton spins, appearing transiently in o-H2 molecules freshly derived from p-H2. For the TSO to be observable, the o-H2 NMR signal must be split into a doublet. In the literature, the splitting is believed to originate from a slow exchange of the dissolved dihydrogen with the dihydride moiety bound to a catalyst present in the reaction mixture. Because this hypothesis may be debatable, in this work a different splitting mechanism is proposed. It employs a residual dipolar coupling (RDC) between the hydrogen protons, originating from a partial orientation of the H2 molecules by the external magnetic field. The orientation effect is due to the anisotropic magnetic polarizability of H2. In a magnetic field of 11.74 T at room temperature, the currently predicted value of the RDC is −0.0024 Hz. Even such small RDC values are sufficient for the PNL effect to be clearly visible in NMR spectra for physically reasonable levels of the TSO in the o-H2 molecules. For RDC values much smaller than the natural linewidth of o-H2, the theoretical frequency distance between the minimum and maximum of PNL proves to be practically independent of the RDC and is of the order of the linewidth. The calculated amplitudes of the PNLs are proportional to the RDC values used in the calculations. [ABSTRACT FROM AUTHOR]

The nuclear magnetic resonance (NMR) spectroscopy of spin-1/2 nuclei with low gyromagnetic ratio is challenging due to the low NMR signal strength. Methodology for the rapid acquisition of 103Rh NMR parameters is demonstrated for the case of the rhodium formate "paddlewheel" complex R h 2 (H C O 2 ) 4 . A scheme is described for enhancing the 103Rh signal strength by polarization transfer from 1H nuclei, which also greatly reduces the interference from ringing artifacts, a common hurdle for the direct observation of low-γ nuclei. The 103Rh relaxation time constants T1 and T2 are measured within 20 min by using 1H-detected experiments. The field dependence of the 103Rh T1 is measured. The high-field relaxation is dominated by the chemical shift anisotropy mechanism. The 103Rh shielding anisotropy is found to be very large: |Δσ| = 9900 ± 540 ppm. This estimate is compared with density functional theory calculations. [ABSTRACT FROM AUTHOR]

Pandit[1] provides a review on the application of magic angle spinning nuclear magnetic resonance (NMR) spectroscopy and related techniques, with which it is possible to access the motion of proteins, pigments, and lipids on sub-nanoseconds to millisecond timescales on very different length scales ranging from solubilized complexes to whole cells. Remarkably, the spectral density includes 50 high-frequency vibrational modes per pigment, besides a low-frequency part characterizing the pigment-protein coupling. Using this technique, excitation energy transfer between the bacteriochlorophyll a pigments of the LH2 complex of purple bacteria is studied. Two important points dealt with in the present Special Topic issue on "Photosynthetic Light-Harvesting and Energy Conversion" are the following: (i) Pigment-protein complexes undergo conformational transitions on many different timescales that include transitions between functionally relevant modes of light harvesting and photoprotection. [Extracted from the article]

A set of antimony(III) compounds containing a ligand (Ar) with a pendant guanidine function (where Ar = 2-[(Me2N)2C N]C6H4) was prepared and characterized. This includes triorgano-Ar3Sb, diorgano-Ar2SbCl and monoorgano-ArSbCl2 compounds and they were characterized by ¹H and 13C NMR spectroscopy and by single-crystal X-ray diffraction analysis (sc-XRD). The coordination capability of Ar3Sb and Ar2SbCl was examined in the reactions with either cis-[PdCl2(CH3CN)2] or PtCl2 and complexes cis-[(κ²-Sb,N-Ar3Sb)MCl2] (M = Pd 1, Pt 2) and [(κ³-N,Sb,N-Ar2SbCl)MCl2] (M = Pd 3, Pt 4) were isolated, while their structures were determined by sc-XRD. Notably, the ligands Ar3Sb and Ar2SbCl exhibit different coordination modes - bidentate and tridentate, respectively - and the antimony exhibits three distinct bonding modes in complexes 1-4, which were also subjected to theoretical studies. [ABSTRACT FROM AUTHOR]

Metal complexes based on mono(arylhydrazino)acenaphthenones (Ar-mhan) are extremely rare. In this work, synthetic routes for previously unknown rhodium complexes containing 2-(pyridin-2-yl)hydrazino acenaphthene-1-one (Py-mhan) are proposed. The interaction of RhCl3·3H2O with Py-mhan, depending on the conditions, led to two anionic complexes: (HPy-mhan)+[Rh(Py-mhan)Cl3] (1) and (NBu4)[Rh(Py-mhan)Cl3] (2). The complexes were characterized using X-ray diffraction analysis, elemental analysis, and IR- and 1H NMR-spectroscopies. The electrochemical properties of complex 2 were investigated using cyclic voltammetry. Complex 2 demonstrated irreversible reduction at −0.69 V (vs. Ag/AgCl), which is accompanied by the elimination of chloride ligands to give a Rh(I) complex namely [Rh(Py-mhan)(CH3CN)] (3). Complex 3 was isolated by electroreduction of complex 2 on a carbon glass electrode and characterized by EDS analysis, CHN analysis, 1H NMR spectroscopy and cyclic voltammetry. For complexes 2 and 3, reversible reduction processes localized on Py-mhan were found. To confirm the nature of electrochemical transformations for complexes 2 and 3 in solution, quantum chemical calculations were performed. [ABSTRACT FROM AUTHOR]

In this investigation, a new micro‐crosslinked anionic polymer resistant to elevated temperature and high salinity, PKDASN, was synthesized using 3‐chloropropyltriethoxysilane (KMB703), N, N‐Dimethylacrylamide (DMAM), 2‐acrylamido‐2‐methylpropanesulfonic acid (AMPS), N‐vinyl caprolactam (NVCL), and sodium (4‐vinyl phenyl)methanesulfonate (SVM) employing free radical polymerization in a water‐based solution. The structure of PKDASN was analyzed using Fourier‐transform infrared spectroscopy, nuclear magnetic resonance spectroscopy, and X‐ray photoelectron spectroscopy, while its microstructure was analyzed using scanning electron microscopy. Thermogravimetric analysis showed that the pyrolysis temperature of PKDASN was above 294°C. Adding KMB703 enables the polymer to form a dense and stable spatial network. This intensified polymer network could interact with bentonite via intermolecular force and Coulomb force and form a dual grid structure, which presents impressive stability and control of filtration in saltwater. This is mainly achieved through creating a "silane coupling layer" on the particle surface by KMB703, which facilitates the crosslinking and aggregation of the polymer, thereby reinforcing the polymer's framework. This implies that under high‐temperature conditions of 230°C, 3 wt% PKDASN can improve the filtration effectiveness of drilling fluids and exhibit resistance to 15 wt% NaCl contamination. American Petroleum Institute filtration(FLAPI) and High temperature and high pressure filtration(FLHTHP) values were 4.6 and 23.0 mL, respectively. Therefore, this investigation provides a novel approach to utilizing the designated silane agent for the advancement of filtration loss additives in drilling fluids resistant to elevated temperature and high salinity. [ABSTRACT FROM AUTHOR]

Recently, there has been a surge in research focusing on triazolone-based energetic materials, propelled by their remarkable properties such as good detonation performance as well as acceptable thermal and physical stability. In this work, a novel combination of the triazolone framework with dinitropyrazoles has been attained using the N-methylene-C-linked approach. Different substituents (NH2, NO2, N3, OH) were utilized on the dinitropyrazole moiety to obtain neutral energetic compounds 3–5 and 8. Furthermore, the hydroxy derivative (compound 8) facilitates the formation of energetic salts 9–13 to fine-tune the overall properties further. All the novel compounds 3–13 were thoroughly characterized by IR, multinuclear NMR spectroscopy, high-resolution mass spectrometry (HRMS), and elemental analysis. Compounds 3, 4, 8, and 10 were further confirmed via15N NMR spectroscopy. The structure of compounds 3 and 8 was also confirmed through single-crystal X-ray diffraction studies. The majority of synthesized compounds showed good thermal stability as well as insensitivity toward external stimuli. Computational studies, including analyses such as Hirshfeld surface, non-covalent interaction, electrostatic potential surface, and HOMO–LUMO analysis, were conducted to examine the influence of substitution at the 4th position on the overall stability of compounds 3, 4, and 8. [ABSTRACT FROM AUTHOR]

Development of energetic materials with enhanced thermostability and diminished sensitivity is one of the main objectives of current research. In this work, an N,N-alkylidene bridge was used to synthesize a series of tricyclic heat-resistant fused ring compounds. The physical and chemical properties of newly synthesized compounds are verified and quantified through experimental and theoretical methods. The structures of all fused compounds were determined through single-crystal X-ray diffraction, elemental analysis, NMR spectroscopy, and IR spectroscopy. Among these compounds, 9-nitro-5,6-dihydrotetrazolo[1,5-a][1,2,4]triazolo[5,1-c]pyrazine (3) and 10-nitro-6,7-dihydro-5H-tetrazolo[1,5-a][1,2,4]triazolo[5,1-c][1,4]diazepine (4) exhibit excellent thermal stability with the decomposition temperatures higher than 300 °C (3: 301 °C and 4: 311 °C). Furthermore, compounds 3 and 4 are more insensitive in comparison with the applied heat-resistant material HNS (3: IS = 33 J, FS > 360 N; 4: IS > 40 J, FS > 360 N; HNS: IS = 5 J, FS = 240 N). Additionally, compound 3 displays significantly superior detonation properties compared to HNS (3: VD = 8021 m s−1, P = 25.8 GPa; HNS: VD = 7612 m s−1, P = 24.3 GPa). The potential of compound 3 as a heat-resistant material is demonstrated by these experimental and theoretical data. [ABSTRACT FROM AUTHOR]

The furan/maleimide Diels–Alder (DA) reaction has been exploited to construct thermally reversible macromolecular structures, such as linear or cross-linked polycondensates, or to cross-link linear polymers, using the free end-type or pending furan and maleimide moieties as the diene and dienophile reagents. Here we report a different approach for the synthesis of homopolymers based on a diol, in which the DA adduct formed by the furan and the maleimide sits within the diol monomer structure. The OH end groups of the diol were used for the synthesis of a polyester and a polyurethane using conventional polycondensation methods and to study their retro DA (rDA) depolymerization through the thermal decomposition of their inner DA adducts. The relevant contribution of this study was however the possibility of synthesizing a copolymer by heating these two polymers together to induce their rDA deconstruction and then lowering the temperature in order to allow the ensuing fragments to recombine statistically by successive DA couplings, thus building the corresponding ester-urethane copolymer. 1H NMR spectroscopy and DSC analysis were employed to confirm the success of this promising approach. [ABSTRACT FROM AUTHOR]

A new aromatic polyketide, alternaphenol B2 (1), and four known compounds (2–5) were isolated from the coral-derived fungus Parengyodontium album SCSIO SX7W11. Their structures were elucidated by high-resolution mass spectrometry, 1D and 2D NMR spectroscopy and comparison with reported literatures. Compounds 1 and 2 exhibited selective inhibitory activity against isocitrate dehydrogenase mutant R132H (IDH1m), with IC50 values of 41.9 and 27.7 μM, respectively. Our findings thus provide a fresh incentive for investigation on IDH1m inhibitors as lead compounds for cancer treatment. [ABSTRACT FROM AUTHOR]

In this study, we reported the construction of 3D supramolecular polymeric networks using per‐imidazole pillar[5]arene (DIMP5) as a host and 1,4‐diiodotetrafluorobenzene (L) as a halogen bond donor in chloroform. The supramolecular polymerization process was characterized by 1H NMR, 19F NMR spectroscopy, and X‐ray single crystal analysis. The C─I⋯N distance (2.78 Å) and C─I⋯N angle (177°) clearly indicated the formation of halogen bonds in the crystal structure. Meanwhile, by introducing adiponitrile (G) as the guest, a supramolecular polymerization of pseudo[2]rotaxanes was also prepared, which was driven by DIMP5‐based host–guest complexations and halogen bonding interactions. [ABSTRACT FROM AUTHOR]

To explore the influence of reaction medium on the copolymerization behavior of acrylamide‐based copolymers, three types of copolymers (P(AM‐St)(ILs), P(AM‐MMA)(ILs), and P(AM‐AMPS)(ILs)) were synthesized by combining insoluble, slightly soluble, and easily soluble monomers with acrylamide in the 1‐butyl‐3‐methylimidazolium tetrafluoroborate ([BMIM]BF4) reaction medium. The reactivity ratio, Fourier transform infrared spectroscopy, 1H NMR spectroscopy, elemental analysis, and scanning electron microscopy were employed to characterize the copolymers' properties. The results indicated that in [BMIM]BF4 copolymerization, the reactivity ratio of AM and St in P(AM‐St)(ILs) decreased, the reactivity ratio of AM in P(AM‐MMA)(ILs) will increase. While the reactivity ratio of MMA will decrease. The reactivity ratio of AM in P(AM‐AMPS)(ILs) will increase and the reactivity ratio of AMPS will decrease. The distribution of AM and St segments in P(AM‐St)(ILs) molecular chains is more uniform and compact. When AM polymerizes with hydrophobic monomers (St) in [BMIM]BF4, its copolymer solution exhibits lower viscosity loss rates in temperature, shear, and salt resistance tests. Therefore, ionic liquids are more suitable as reaction media for the synthesis of hydrophobic‐modified polyacrylamides, which facilitate a more uniform distribution of hydrophobic monomers within the copolymer chains and exhibit enhanced resistance to temperature, salt, and shear stresses. [ABSTRACT FROM AUTHOR]

This study investigates the effect of oxidized sucrose (OS) on selected functional properties of cast films from lupin protein isolate (LPI). LPI with a protein content larger than 0.9 g g−1 was obtained by alkaline extraction and isoelectric precipitation from bitter narrow‐leaved lupins (Lupinus angustifolius L.). OS was synthesized by vicinal diol cleavage using sodium periodate and was successfully characterized by Fourier‐transform infrared‐, 1H‐nuclear magnetic resonance spectroscopy, and aldehyde titration. Films were produced from heated (85°C, 30 min), alkaline (pH 10), aqueous solutions of LPI (0.1 mL−1), glycerol (300 mg g−1 of LPI) and OS (25, 50, 75, and 100 mg g−1 of LPI). The effect of covalent crosslinking between OS and protein chains was studied by investigating mechanical properties, moisture content, total soluble matter, water vapor permeability, and protein solubility for all films. LPI films produced with the addition of OS showed increased mechanical performance as the tensile strength was increased from 3.5 up to 9.3 MPa and elongation at break values could be raised from 118% to 176%. Taken together with the facts that these films are thermoformable and show improved wet strength compared with control films, make them promising materials for sustainable packaging and short‐term applications in agriculture and forestry. [ABSTRACT FROM AUTHOR]

Using acrylic acid advanced ester and styrene as raw materials, the long-chain polyester polymer, polyacrylic acid advanced ester-styrene pour point depressant (P-PPD), was synthesized by molecular design, and its structure was characterized by infrared spectroscopy and nuclear magnetic resonance. In addition, this study experimentally investigated the effect of P-PPD on the phase equilibrium and induction time of natural gas hydrate inhibitors in deionized water (DW) and crude oil/water (O/W) systems, respectively. Polyvinylpyrrolidone (PVP) and mono ethylene glycol (EG) were selected as representatives of kinetic hydrate inhibitor (KHIs) and thermodynamic hydrate inhibitor (THIs), respectively. The results exhibit that P-PPD played a sight role in the phase equilibrium of hydrate, while the addition of P-PPD significantly prolonged the induction time of methane hydrate both in O/W + PVP, OW + EG and O/W + PVP + EG system, indicating that the addition of as-synthesized PPD has a synergistic inhibition effect on the nucleation ability of methane hydrate and can prevent hydrate from formatting during oil and gas transport process, and thus guarantee the flow assurance. The findings of this work will provide a data reference for the hybrid use of hydrate inhibitors and pour point depressants in oil and gas transport. [ABSTRACT FROM AUTHOR]

Traumatic brain injury (TBI) is a major cause of morbidity and mortality, impacting healthcare systems and economies. Early identification of poor outcomes is crucial for effective treatment. This systematic review assesses the prognostic value of computed tomography (CT) and magnetic resonance imaging (MRI) findings in predicting poor neurological outcomes and mortality in the acute phase of TBI. A comprehensive search of Scopus, MEDLINE, and Web of science databases was performed to identify studies examining CT and MR-based imaging findings and their association with poor outcomes as assessed by Glasgow outcome score as well as mortality within the early acute phase of TBI following injury/admission. Qualitative evaluation of included studies revealed several imaging sequences that modify the outcome of the patients, including extra-axial and intra-axial hemorrhage, swirl sign, contrast extravasation, midline shift, closed and open cranial cisterns, signs of edema, presence of cranial fractures, intracranial hemorrhage, cerebral microbleeds, diffuse axonal injury, apparent diffusion coefficient and fractional anisotropy in diffusion tensor imaging, as well as, concentrations of brain metabolites(N-acetyl aspartate, Creatinine, Choline, Myo-inositol, glutamate, and glutamine) in magnetic resonance spectroscopy. Among these markers, subarachnoid hemorrhage (SAH) and subdural hematoma (SDH) emerged as the most predictive of poor outcomes based on meta-analysis findings. SAH was significantly associated with an increased risk of mortality (OR: 3.35, 95% CI: 2.41–4.65, I²=51.3%) and poor outcomes (OR: 2.69, 95% CI: 2.44–2.96, I²=0%). Similarly, SDH correlated with higher mortality risk (OR: 2.44, 95% CI: 2.14–2.78, I²=0%) and worse outcomes (OR: 2.00, 95% CI: 1.12–3.59, I²=60.9%). In contrast, epidural hematoma (EDH) was linked to better outcomes (OR: 0.60, 95% CI: 0.52–0.68, I²=0%) but not significantly associated with mortality (OR: 0.38, 95% CI: 0.09–1.65, I²=73.7%). The results of this systematic review and meta-analysis provide an overview of clinically feasible imaging markers of prognostic value and may inform clinical decision-making in the future. [ABSTRACT FROM AUTHOR]

To determine the accuracy of magnetic resonance imaging-proton density fat fraction (MRI-PDFF) measurements for detecting liver fat content in potential living liver donors and to compare these results using liver biopsy findings. METHODS A total of 139 living liver donors (men/women: 83/56) who underwent MRI between January 2017 and September 2021 were included in this analysis retrospectively. The PDFFs were measured using both MR spectroscopy (MRS) and chemical shift-based MRI (CS-MRI) for each donor in a blinded manner. RESULTS Significant positive correlations were found between liver biopsy and MRS-PDFF and CS-MRI PDFF in terms of hepatic steatosis detection [r = 0.701, 95% confidence interval (CI): 0.604-0.798, r = 0.654, 95% CI: 0.544-0.765, P < 0.001, respectively). A weak level correlation was observed between liver biopsy, MRI methods, and vibration-controlled transient elastography attenuation parameters in 42 available donors. Based on receiver operating characteristic (ROC) analysis, MRS-PDFF and CSMRI PDFF significantly distinguished >5% of histopathologically detected hepatic steatosis with an area under the ROC curve (AUC) of 0.837 ± 0.036 (P < 0.001, 95% CI: 0.766-0.907) and 0.810 ± 0.036 (P < 0.001, 95% CI: 0.739-0.881), respectively. The negative predictive values (NPVs) of MRS-PDFF and CS-MRI PDFF were 88.3% and 81.3%, respectively. In terms of distinguishing between clinically significant hepatic steatosis (≥10% on histopathology), the AUC of MRS-PDFF and CS-MRI were 0.871 ± 0.034 (P < 0.001 95% CI: 0.804-0.937) and 0.855 ± 0.036 (P < 0.001, 95% CI: 0.784-0.925), respectively. The NPVs of MRS-PDFF and CS-MRI were 99% and 92%, respectively. CONCLUSION The methods of MRS-PDFF and CS-MRI PDFF provide a non-invasive and accurate approach for assessing hepatic steatosis in potential living liver donor candidates. These MRI PDFF techniques present a promising clinical advantage in the preoperative evaluation of living liver donors by eliminating the requirement for invasive procedures like liver biopsy. [ABSTRACT FROM AUTHOR]

Background/Objectives: Huntington's disease (HD) is a fully penetrant neurodegenerative disease with a profound effect on quality of life. In recent years, there has been rapid growth in the description of its pathogenesis and diagnosis. Magnetic resonance spectroscopy (MRS) measurements can aid in the discrimination between premanifest Huntington's disease (Pre-HD) and healthy control (HC) subjects to establish early supportive and symptomatic management. Our objective was to evaluate metabolic changes using MRS to shed light on its potential as a biomarker through a systematic review. Methods: We followed the PRISMA guidelines, extracting articles from PubMed, Scopus, and the Virtual Health Library. We included patients with pre-HD, HD, and HC subjected to MRS, reporting the concentration of metabolites in at least one brain region. Results: In the putamen, N-acetyl Aspartate (NAA) was significantly decreased in 77.9% and total NAA (tNAA) was decreased in 72.4% of cases; no significant difference was found in 27.5% (n = 19) of cases. Furthermore, when looking into HD vs. pre-HD in the putamen, tNAA and NAA were decreased in 100% of participants. In the caudate nucleus, NAA and creatine were significantly decreased in 100% of HD in comparison to pre-HD participants, whereas tNAA showed a significant decrease in only 50%. Conclusions: MRS can be a relevant tool for the early diagnosis of HD; potential objective biomarkers related to its onset and pathogenesis exist and show differences between controls, pre-HD and HD patients. However, an effort should be made to standardize MRS methodology and reporting in subsequent studies. [ABSTRACT FROM AUTHOR]

Background: The role of the cerebellum in Parkinson's disease (PD), particularly in tremor-dominant subtypes, is increasingly recognized. Magnetic resonance imaging (MRI) and magnetic resonance spectroscopy (MRS) provide anatomical and metabolic insights, suggesting compensatory hyperactivity or degenerative changes in the cerebellum in PD. Volumetric analysis of cerebellar structures in MRI images, combined with metabolic profiles from MRS, offers possibilities for differentiating PD from essential tremor (ET). The cerebellum may be a potential therapeutic target due to its role in neurocircuitry of PD and ET. Methods: Brain structural data were obtained using MRI, and cerebellar metabolic profiles, focusing on the quantification of N-acetylaspartate (NAA), choline, and creatine peaks were obtained using MRS. This study enrolled patients with ET and PD, both with and without tremor, as well as disease controls with cerebellar atrophy (including spinocerebellar ataxia and multiple system atrophy). Volumetric analysis of cerebellar structures was performed. Differences in MRI and MRS parameters were analyzed using one-way analysis of covariance with a significance threshold of p < 0.05. Results: From November 2018 to March 2023, 111 patients were enrolled, including 29 ET, 29 cerebellar atrophy, 12 PD without tremor, and 41 PD with tremor. No significant differences in cerebellar volume and N-acetylaspartate/creatine and choline/creatine ratios were found between ET and PD with tremor. Conclusions: This preliminary retrospective study suggests similarities in cerebellar structures and metabolic profiles between ET and PD, highlighting the need for advanced imaging techniques to better differentiate between these conditions. Future research should integrate clinical data, such as tremor severity and cognitive assessments, to explore the relationships with cerebellar MRI parameters. [ABSTRACT FROM AUTHOR]

In this study, a novel bio-based acrylic monomer derived from cardanol was synthesized and used in order to prepare acrylic copolymers that can be applied as thermoplastic polymers alone initially and then curable with the help of some driers to get a crosslink network similar to thermosetting polymers with their hydrophobic long alkyl chains having double bonds in their chemical structure. The synthesized polymers have the ability to be used in the paint or varnish formulations with or without paint driers. The synthesized monomers and polymers were characterized by gel permeation chromatography (GPC), Fourier transform infrared spectroscopy (FT-IR) and proton nuclear magnetic resonance spectroscopy (1H NMR). Thermal properties of the polymers and obtained coatings therefrom were studied by differential scanning calorimeter (DSC) and thermal gravimetric analysis (TGA). The varnish's thermal and coating characteristics, such as its adhesion, gloss, hardness, salt spray resistance, and touch and hard drying times, were examined and analyzed. The results showed that the bio-based cardanol moieties improved the coatings' resistance to chemicals and saltwater exposure as well as their thermal and mechanical characteristics through the incorporation aromatic and long linear alkyl chains. The block copolymers with cardanol units were used both on its own to produce thermoplastic polymeric films and in conjunction with driers to get thermoset crosslinking networks. The contact angle of thermoset polymeric films with driers measured as 77° but in case of thermoplastic blank polymer, it was 61°. Furthermore, the Tg of blank polymer was 13.37 °C, but with the addition of 10% cardanol units and a small amount of driers, the Tg was increased to 53.12 °C. [ABSTRACT FROM AUTHOR]

The use of sequential proton magnetic resonance spectroscopy (MRS) to follow glutamate and gamma‐aminobutyric acid (GABA) changes during functional task‐based paradigms, functional MRS (fMRS), has increased. This technique has been used to investigate GABA dynamics during both sensory and behavioural tasks, usually with long 'block design' paradigms. Recently, there has been an increase in interest in the use of short stimuli and 'event‐related' tasks. While changes in glutamate can be readily followed by collecting multiple individual transients (or shots), measurement of GABA, especially at 3 T, is usually performed using editing techniques like Mescher–Garwood point‐resolved spectroscopy (MEGA‐PRESS), which by its nature is a dual shot approach. This poses problems when considering an event‐related experiment, where it is unclear when GABA may change, or how this may affect the individual subspectra of the MEGA‐PRESS acquisition. To address this issue, MEGA‐PRESS data were simulated to reflect the effect of a transient change in GABA concentration due to a short event‐related stimulus. The change in GABA was simulated for both the ON and OFF subspectra, and the effect of three different conditions (increase only during ON acquisition, increase during OFF acquisition and increase across both) on the corresponding edited GABA spectrum was modelled. Results show that a transient increase in GABA that only occurs during the ON subspectral acquisition, while not changing the results much from when GABA is changed across both conditions, will give a much larger change in the edited GABA spectrum than a transient increase that occurs only during the OFF subspectral acquisition. These results suggest that researchers should think carefully about the design of any event‐related fMRS studies using MEGA‐PRESS, as well as the analysis of other functional paradigms where transient changes in GABA may be expected. Experimental design considerations are therefore discussed, and suggestions are made. [ABSTRACT FROM AUTHOR]

Three sulfur-containing alkaloids aplospojaveedins A-C (1-3) with a hitherto undescribed carbon skeleton comprising octahy-dronaphthalene, α, β-unsaturated lactam and glycine-cysteine moieties were isolated from Aplosporella javeedii. Their structures were elucidated by 1D and 2D NMR spectroscopy, HR-MS, X-ray diffraction analysis, DFT-NMR and TDDFT-ECD calculations. A plausible biosynthetic pathway and putative targets are described. The blind docking suggested that 1-3 may have functional effects on several putative targets such as the GPCR cannabinoid receptor 2 or the integrin α5β1 complex. [ABSTRACT FROM AUTHOR]

Mitragyna speciosa is a perennial plant native to Asia, well known for its psychoactive properties. Its major alkaloid mitragynine is known to have sedative and euphoric effects. Hence, the plant has been a subject of abuse, leading to addiction, necessitating efficient analytical methods to detect its psychoactive constituents. However, current chromatography‐based methods for detecting the alkaloids are time consuming and costly. Quantitative nuclear magnetic resonance (qNMR) spectroscopy emerges as a promising alternative due to its nondestructive nature, structural insights, and short analysis time. Hence, a rapid and precise qNMR method was developed to quantify selected major psychoactive alkaloids in various parts of M. speciosa. Mitragynine, specioliatine, and speciogynine were quantified in relation to the integral value of the ‐OCH3 groups of the alkaloids and the internal standard 1,4‐dinitrobenzene. The precision and reproducibility of the method gave a relative standard deviation (RSD) of 2%, demonstrating the reliability of the method. In addition, the method showed excellent specificity, sensitivity, high linearity range (R2 = 0.999), and limits of detection (LOD) and quantification (LOQ) values. The analysis revealed that the red‐veined M. speciosa leaves contained higher levels of mitragynine (32.34 mg/g), specioliatine (16.84 mg/g) and speciogynine (7.69 mg/g) compared to the green‐veined leaves, stem bark, or fruits. [ABSTRACT FROM AUTHOR]

Purpose: Retrospective frequency‐and‐phase correction (FPC) methods attempt to remove frequency‐and‐phase variations between transients to improve the quality of the averaged MR spectrum. However, traditional FPC methods like spectral registration struggle at low SNR. Here, we propose a method that directly integrates FPC into a 2D linear‐combination model (2D‐LCM) of individual transients ("model‐based FPC"). We investigated how model‐based FPC performs compared to the traditional approach, i.e., spectral registration followed by 1D‐LCM in estimating frequency‐and‐phase drifts and, consequentially, metabolite level estimates. Methods: We created synthetic in‐vivo‐like 64‐transient short‐TE sLASER datasets with 100 noise realizations at 5 SNR levels and added randomly sampled frequency and phase variations. We then used this synthetic dataset to compare the performance of 2D‐LCM with the traditional approach (spectral registration, averaging, then 1D‐LCM). Outcome measures were the frequency/phase/amplitude errors, the SD of those ground‐truth errors, and amplitude Cramér Rao lower bounds (CRLBs). We further tested the proposed method on publicly available in‐vivo short‐TE PRESS data. Results: 2D‐LCM estimates (and accounts for) frequency‐and‐phase variations directly from uncorrected data with equivalent or better fidelity than the conventional approach. Furthermore, 2D‐LCM metabolite amplitude estimates were at least as accurate, precise, and certain as the conventionally derived estimates. 2D‐LCM estimation of FPC and amplitudes performed substantially better at low‐to‐very‐low SNR. Conclusion: Model‐based FPC with 2D linear‐combination modeling is feasible and has great potential to improve metabolite level estimation for conventional and dynamic MRS data, especially for low‐SNR conditions, for example, long TEs or strong diffusion weighting. [ABSTRACT FROM AUTHOR]

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Endometriosis has a wide range of clinical manifestations, and the disease course is unpredictable, making the diagnosis a challenging task. Despite significant advances in the pathophysiology of endometriosis and various proposed theories, the exact etiology is not fully understood and is still unknown. The most commonly used biomarker of endometriosis is CA-125, however, it is nonspecific and is applied for cancers diagnosis. Therefore, the development of reliable noninvasive diagnostic tests for the early diagnosis of endometriosis remains one of the top priorities. Omics technologies are very promising approaches for constructing diagnostic models and biomarker discovery. Their use can greatly facilitate the study of such a complex disease as endometriosis. Nowadays, powerful analytical platforms commonly used in omics, such as gas and liquid chromatography with mass spectrometry and nuclear magnetic resonance (NMR) spectroscopy, have proven to be a promising tools for biomarker discovery. The aim of this review is to summarize the various features of the analytical approaches, practical challenges and features of gas and liquid chromatography with MS and NMR spectroscopy (including sample processing protocols, technological advancements, and methodology) used for profiling of metabolites, lipids, peptides and proteins in physiological fluids and tissues from patients with endometriosis. In addition, this report devotes special attention to the issue of how comprehensive analyses of these profiles can effectively contribute to the study of endometriosis. The search query included reports published between 2012 and 2022 years in PubMed, Web-of-Science, SCOPUS, Science Direct. [ABSTRACT FROM AUTHOR]

Poly(vinyl chloride) (PVC) is a widely employed plastic across diverse industries and is often associated with plasticizers, additives that decrease the inherent rigidity and brittleness of the material. Conventional phthalate‐based plasticizers raise substantial toxicity concerns, encouraging the exploration of bio‐based alternatives. One such alternative is the inedible oil, cashew nutshell liquid (CNSL), mainly composed of cardanol and cardol. Recent efforts have focused on developing a cardanol‐based PVC plasticizers but the isolation of cardanol involves time‐consuming, energy‐intensive, and costly steps, limiting its market competitiveness. This study aims to assess for the first time, the efficiency of cardol esters, synthesized using acetic acid and different fatty acids (octanoic acid and myristic acid), in order to evaluate the influence of the alkyl chain on plasticizer properties. The chemical structures of these plasticizers were fully characterized by 1H NMR spectroscopy, and the mechanical properties and thermal behavior of PVC films plasticized with these additives were investigated. Finally, the endocrine activity was evaluated for cardol and cardanol acetates. [ABSTRACT FROM AUTHOR]

The aqueous photolysis of four pharmaceuticals with varying fluorinated functional groups was assessed under neutral, alkaline, advanced oxidation, and advanced reduction conditions with varying light sources. Solar simulator quantum yields were 2.21 × 10−1 mol Ei−1 for enrofloxacin, 9.36 × 10−3 mol Ei−1 for voriconazole, and 1.49 × 10−2 mol Ei−1 for flecainide. Florfenicol direct photolysis was slow, taking 150 h for three degradation half‐lives. Bimolecular rate constants between pharmaceuticals and hydroxyl radicals were 109 to 1010 M−1 s−1. Using a combined quantitative fluorine nuclear magnetic resonance spectroscopy (19F‐NMR) and mass spectrometry approach, fluorine mass balances and photolysis product structures were elucidated. Enrofloxacin formed a variety of short‐lived fluorinated intermediates that retained the aryl F motif. Extended photolysis time led to complete aryl F mineralization to fluoride. The aliphatic F moiety on florfenicol was also mineralized to fluoride, but the resulting product was a known antibiotic (thiamphenicol). For voriconazole, the two aryl Fs contributed more to fluoride production compared with the heteroaromatic F, indicating higher stability of the heteroaromatic F motif. The two aliphatic CF3 moieties in the flecainide structure remained intact under all conditions, further supporting the stability of these moieties found in per‐ and polyfluoroalkyl substances under a variety of conditions. The advanced treatment conditions generating hydroxyl radicals or hydrated electrons accelerated the degradation, but not the defluorination, of flecainide. The combination of 19F‐NMR and mass spectrometry proved powerful in allowing identification of fluorinated products and verifying the functional groups present in the intermediates and products. The results found in the present study will aid in the understanding of which fluorinated functional groups should be incorporated into pharmaceuticals to ensure organofluorine byproducts are not formed in the environment and help determine the water‐treatment processes that effectively remove specific pharmaceuticals and more generally fluorinated motifs. Environ Toxicol Chem 2024;43:2285–2296. © 2023 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC. [ABSTRACT FROM AUTHOR]

Two new cucurbitane-type triterpenoid saponins, 2,20β,22β-trihydroxy-16α,23(R)-epoxycucurbita-1,5,24-triene-3,11-dione 2-O-β-D-glucopyranoside (1), 2,20β,22α-trihydroxy-16α,23(S)-epoxycucurbita-1,5,11,24-tetraene-3-one 2-O-β-D-glucopyranoside (2) were isolated from the fruit of Citrullus colocynthis (L.) Schrad. Their structures were elucidated by mass spectrometry, IR, 1D, and 2D NMR spectroscopy, etc. Besides, both of the compounds showed significant hepatoprotective activities at 10 μM against paracetamol-induced HepG2 cell damage. [ABSTRACT FROM AUTHOR]

One new bithiophene derivative, 5-(but-3-en-1-yn-1-yl)-5′-(methoxymethyl)-2,2′-bithiophene (1), along with twelve known compounds, senecioester (2), tiglinsaureester (3), 5-acetoxymethyl-2′-(but-3-en-1-yn-1-yl)-2,5′-bithiophene (4), 5-(4-isovaleroyloxybut-1-ynyl)-2,2′-bithiophene (5), 5-hydroxymethyl-(2,5′:2′,5′′)-terthienyl tiglate (6), 5-hydroxymethyl-(2,5′:2′,5′′)-terthienyl agelate (7), 5- hydroxymethyl-2,5′:2′,5′′-terthiophene dimethylacrylate (8), 5-methoxymethyl-2,2′:5′,2′′-terthiophene (9), α-terthiophene (10), 1,3,8,9-tetrahydroxycoumestan 3-sulfate (11), demethylwedelolactone (12), and wedelolactone (13) were isolated from the methanol extract of aerial parts of Eclipta prostrata (L.) L. All isolated compounds were evaluated for the protective ability on the HepG2 cells. At the concentration of 100 μM, compounds 11-13 showed the highest hepatoprotective effects, with HepG2 cell viability ranging from 38.68% to 48.54%. Bithiophenes showed higher hepatoprotective cell viability than terthiophenes. [ABSTRACT FROM AUTHOR]

Three new prenylated C6–C3 compounds (1–3), together with two known prenylated C6–C3 compounds (4–5) and one known C6–C3 derivative (6), were isolated from the roots of Illicium brevistylum A. C. Smith. The structures of 1–3 were elucidated by spectroscopic methods including 1D and 2D NMR, HRESIMS, CD experiments and ECD calculations. The structure of illibrefunone A (1) was confirmed by single-crystal X-ray diffraction analysis. All compounds were evaluated in terms of their anti-inflammatory potential on nitric oxide (NO) generation in lipopolysaccharide-stimulated murine RAW264.7 macrophages and murine BV2 microglial cells, antiviral activity against Coxsackievirus B3 (CVB3) and influenza virus A/Hanfang/359/95 (H3N2). Compounds 3 and 4 exhibited potent inhibitory effects on the production of NO in RAW 264.7 cells with IC50 values of 20.57 and 12.87 μM respectively, which were greater than those of dexamethasone (positive control). Compounds 1 and 4–6 exhibited weak activity against Coxsackievirus B3, with IC50 values ranging from 25.87 to 33.33 μM. [ABSTRACT FROM AUTHOR]

Twelve compounds, comprising of four new ones, 6β,7α-limondiol (1) and ethyl 19-hydroxyisoobacunoate diosphenol (2), N-benzoyl 3-prenyltyramine (9) and 9-O-methyl integrifoliodiol (12), were isolated from the twigs with leaves of Tetradium trichotomum. The structures were elucidated by analysis of MS, NMR, and single-crystal X-ray diffraction. Compounds 1, 6, 8, 9 and 12 exhibited immunosuppressive activities in vitro against the proliferation of ConA-induced T lymphocytes and LPS-induced B cells. [ABSTRACT FROM AUTHOR]

Three new flavonoids including two isoflavanones sophortones A and B (1 and 2), and one chalcone sophortone C (3) were isolated from the roots of Sophora tonkinensis. Their structures were established by UV, IR, HRESIMS, and NMR data. The absolute configurations of 1 and 2 were determined by electronic circular dichroism (ECD) calculations. [ABSTRACT FROM AUTHOR]

A new cladosporol derivative xylophilum A (1), together with 10 known compounds (2–11), were isolated from the rice fermentation of the fungus Cladosporium xylophilum. Their structures were established by extensive spectroscopic methods and comparison of their NMR data with literatures. The antimicrobial activity of compound 1 against 11 kinds of pathogenic microbial was evaluated, but no significant activity was found (MIC >100 μg/ml). [ABSTRACT FROM AUTHOR]

In this study, we introduce a novel indole‐containing pyridine‐based Schiff base, (E)‐2‐({[bis(pyridin‐2‐yl)methylidene]hydrazin‐1‐ylidene}methyl)‐1H‐indole, C20H15N5 (2‐DPHI), and its cadmium(II) complex poly[[2‐({[bis(pyridin‐2‐yl)methylidene]hydrazin‐1‐ylidene}methyl)‐1H‐indole]di‐μ‐chlorido‐cadmium(II)], [CdCl2(C20H15N5)]n (pCd2), as potential anticancer agents. The Schiff base was synthesized by reacting dipyridylmethanone hydrazone with indole‐2‐formaldehyde, while the cadmium complex was prepared by combining CdCl2 and 2‐DPHI in methanol at room temperature. Both compounds were evaluated for their cytotoxicity against three human cancer cell lines (A375, A549 and HeLa) and a normal cell line (HFF‐1). The ligand 2‐DPHI exhibited notable antitumour activity, with an IC50 value of 12.22 µM against A375 and 15.17 µM against A549 after 48 h, while the pCd2 complex showed an even stronger inhibition of A375 cells, with an IC50 value of 4.88 µM, outperforming both 2‐DPHI and CdCl2. Both compounds demonstrated lower toxicity towards normal cells compared to cancer cells. The structures of 2‐DPHI and pCd2 were fully characterized using single‐crystal X‐ray diffraction, elemental analysis, high‐resolution mass spectrometry and FT–IR, 1H NMR, 13C NMR and UV–Vis spectroscopy. [ABSTRACT FROM AUTHOR]

Context Bone marrow adiposity (BMAT) alterations in patients with type 2 diabetes mellitus (T2DM) may contribute to adverse bone effects. Objective Characterization of BMAT content and composition in patients with well-controlled T2DM. Methods This cross-sectional study included 2 groups of postmenopausal women: one with T2DM and the other without. The proton density fat fraction (PDFF) of the lumbar spine and proximal femur, comprising the femoral head, neck, and diaphysis, was assessed using chemical shift-based water-fat separation imaging (WFI). Magnetic resonance imaging with spectroscopy (1H-MRS) was performed in a subgroup of participants to confirm the PDFF measurements and determine the apparent lipid unsaturation level (aLUL) at the L3 vertebrae and femoral neck. The association of imaging-based PDFFs and aLUL between diabetes groups was investigated by adjusting for confounding factors using a linear mixed model. Results Among 199 participants, patients with T2DM (n = 29) were significantly heavier (P <.001) and had a higher bone mineral density (BMD) (P <.001 for all sites) than nondiabetic patients (n = 170). When PDFFs were compared after adjusting for age, body mass index (BMI), and BMD, the femoral head WFI-based PDFF was lower in patients with T2DM (mean [standard error] 88.0% [0.7] vs 90.6% [0.3], P <.001). Moreover, the aLUL at the L3 vertebrae was lower in patients with T2DM (n = 16) than in without (n = 97) (mean [standard error] 3.9% [0.1] vs 4.3% [0.1], P =.02). Conclusion The content and composition of BMAT are modified in postmenopausal women with T2DM and these changes occur at specific sites. [ABSTRACT FROM AUTHOR]

Solution nuclear magnetic resonance (NMR) spectroscopy is a powerful technique for characterizing protein–protein interactions. NMR-monitored titration proves to be effective in determining dissociation constants, particularly for Kd values in the micromolar to millimolar range. In conventional NMR titrations, planning for optimal titration conditions requires a prior estimate of Kd. In addition, a highly concentrated ligand stock solution is often required, posing challenges when the ligand exhibits limited solubility and stability at elevated concentrations. To overcome these constraints, we propose a simulation-guided "swapping" protocol for NMR titrations. Guided by simulations of the binding curves, two samples, one with zero and the other with maximum ligand concentration, but both containing identical protein concentrations, initiate the titration. Using a "swapping" strategy, intermediate ligand concentrations in between those of the two initial samples are generated without the need of a concentrated ligand stock, while maintaining constant protein concentration. More importantly, this protocol facilitates estimation of Kd by early titration points and allows on-the-fly optimization of the titration points. The proposed approach enhances the efficiency of NMR titrations and provides a straightforward means to optimize the experimental conditions for the titrations. [ABSTRACT FROM AUTHOR]

Three novel phenolic compounds were isolated from the heartwood of Millettia pendula along with eight known compounds. Among the known compounds, six were isolated from this species for the first time. Structural determination of the isolated compounds was accomplished using 1D and 2D nuclear magnetic resonance spectroscopy and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Two of the isolated compounds, 2 and 6, showed red and purple pigmentation, respectively. These compounds contained a conjugated π system composed of benzofuran and p-benzoquinone moieties. We therefore hypothesize that a hydroquinone moiety, present in precursors of 2 and 6, is autoxidized by activated oxygen in the air to form p-benzoquinone. The difference in colors between these two compounds was due to the difference in the B ring substituents. Expansion of their conjugated pi systems allows 2 and 6 to absorb and reflect light in the visible region, and results in the characteristic purple coloring of M.pendula. [ABSTRACT FROM AUTHOR]

Plant biomass, in particular forestry wastes, is a promising renewable feedstock for deep chemical processing. Organosolv methods allow the use of underutilized lignin. The synthesis of modified polymers by azo coupling with the use of aspen (Populus tremula) ethanol lignin and its sulfated modification is studied. The success of the synthesis has been proven and the features of the structure and properties of the synthesized samples were studied by the physicochemical techniques, including Fourier transform infrared and nuclear magnetic resonance spectroscopy, gel permeation chromatography and thermogravimetric analysis. It was shown that the new azopolymers have the ability to photoisomerize, which opens up prospects for their high-tech applications. The modified lignins are proven to be bioactive antioxidants. [ABSTRACT FROM AUTHOR]

Two Mn-phosphinophosphinine complexes were synthesised from reaction of the proligand with [MnBr(CO)5] at 80 °C for 2 h; 2-diphenylphosphino-3-methyl-6-trimethylsilylphosphinine manganese tricarbonyl bromide (2TMS) and 2-diphenylphosphino-3-methyl-phosphinine manganese tricarbonyl bromide (2H). 31P{1H} NMR spectroscopy revealed characteristic chemical shifts for the phosphinine and phosphine donors bound to Mn (255.4 and 23.7 ppm for 2TMS; 234.2 and 24.8 ppm for 2H), and single crystal X-ray diffraction established the structure of the chelating complex 2TMS. Rapid reaction of both complexes with water was observed with 2TMS reacting to eventually yield a single product, syn-3TMS, from the syn-1,2-addition of water across the P＝C multiple bond on the bromide face, confirmed by X-ray diffraction for both an unsolvated and solvated structure, where MeOH was found to be H-bonding to the P-OH functionality. The reaction of 2R with dry methanol gave multiple products that were not in equilibrium with each other, and the molecular structure of one isomer was definitively established by X-ray diffraction as an unusual 1,4-addition product (1,4-4TMS). However, reaction of 2R with methanol in the presence of trace water showed that hydrolysis products 3R were formed preferentially. Both phosphinine complexes acted as pre-catalysts for the Guerbet upgrading of methanol/ethanol to isobutanol at 180 °C over 90 h, giving yields of isobutanol (based on moles of ethanol) of 22% for 2TMS and 27% for 2H. This is superior to known Mn dppm complexes [dppm = bis(diphenylphosphino)methane], including the 21% yield recorded for the best derivative [MnBr(κ2-PPh2C(H)PhPPh2)(CO)3] shown to date. [ABSTRACT FROM AUTHOR]

Background: A growing body of literature classifies autism spectrum disorder (ASD) as a heterogeneous, complex neurodevelopmental disorder that often is identified prior to three years of age. We aim to provide a narrative review of key structural and functional properties that differentiate the neuroimaging profile of autistic youth from their typically developing (TD) peers across different neuroimaging modalities. Methods: Relevant studies were identified by searching for key terms in PubMed, with the most recent search conducted on September 1, 2023. Original research papers were included if they applied at least one of seven neuroimaging modalities (structural MRI, functional MRI, DTI, MRS, fNIRS, MEG, EEG) to compare autistic children or those with a family history of ASD to TD youth or those without ASD family history; included only participants <18 years; and were published from 2013 to 2023. Results: In total, 172 papers were considered for qualitative synthesis. When comparing ASD to TD groups, structural MRI-based papers (n = 26) indicated larger subcortical gray matter volume in ASD groups. DTI-based papers (n = 14) reported higher mean and radial diffusivity in ASD participants. Functional MRIbased papers (n = 41) reported a substantial number of between-network functional connectivity findings in both directions. MRS-based papers (n = 19) demonstrated higher metabolite markers of excitatory neurotransmission and lower inhibitory markers in ASD groups. fNIRS-based papers (n = 20) reported lower oxygenated hemoglobin signals in ASD. Converging findings in MEG- (n = 20) and EEG-based (n = 32) papers indicated lower event-related potential and field amplitudes in ASD groups. Findings in the anterior cingulate cortex, insula, prefrontal cortex, amygdala, thalamus, cerebellum, corpus callosum, and default mode network appeared numerous times across modalities and provided opportunities for multimodal qualitative analysis. Conclusions: Comparing across neuroimaging modalities, we found significant differences between the ASD and TD neuroimaging profile in addition to substantial heterogeneity. Inconsistent results are frequently seen within imaging modalities, comparable study populations and research designs. Still, converging patterns across imaging modalities support various existing theories on ASD. [ABSTRACT FROM AUTHOR]