27Al Satellite transition spectroscopy (SATRAS) has been used to extract both the quadrupole interaction and its distribution width from MAS spectra of glasses. Using this method a measurement at a single magnetic field strength allows one to obtain the true chemical shifts and the quadrupole interaction (and its distributions) with high accuracy, including quantification of the results. In contrast to earlier investigations the central transition MAS lineshapes can be described without assumptions and give correct relative proportions of differently coordinated Al species in glasses. The distribution model for the quadrupole interaction and the resulting MAS lineshapes are discussed in detail including a description of the experimental requirements. Experimental results of 27Al SATRAS spectra of a ternary Al2O3-B2O3-P2O5 glass exhibiting 4-, 5-, and 6-coordinated aluminum species clearly prove different mean values and distribution widths for the quadrupole interaction in the various AlOx polyhedra.
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http://dx.doi.org/10.1016/0926-2040(93)90065-u | DOI Listing |
J Ethnopharmacol
January 2025
Faculty of Functional Food and Wine, Shenyang Pharmaceutical University, Shenyang 110016, P.R. China. Electronic address:
Ethnopharmacological Relevance: Schisandra chinensis, a traditional functional Chinese medicine, is known for its ability to tonify the kidneys, calm the heart, and tranquilize the mind. Recent pharmacological research has demonstrated its anti-inflammatory and neuroprotective effects.
Aim Of The Study: We had previously demonstrated that Schisandra chinensis lignans (SCL) promote microglia polarization to M2 phenotype via targeting cannabinoid receptor type-2 (CB2R) to exert antidepressant effects.
J Magn Reson
January 2025
NMR Research Unit, University of Oulu, P.O. Box 3000, FI-90014, Finland. Electronic address:
Spin relaxation is modelled using the so-called relaxation superoperator Γˆˆ. Analytic forms of Γˆˆ have been derived in the literature in the simplest cases of one- or two-spin systems, with S=12 nuclei and no more than two different simultaneous relaxation mechanisms involved. Beyond that, for systems of more than two spins, with S>12 and/or multiple relaxation mechanisms at play, the derivations become notoriously complicated, which is why analytic relaxation theory has mostly been considered a dead end.
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210, United States.
Stacking interactions are a recurring motif in supramolecular chemistry and biochemistry, where a persistent theme is a preference for parallel-displaced aromatic rings rather than face-to-face π-stacking. This is typically explained in terms of quadrupole-quadrupole interactions between the arene moieties but that interpretation is inconsistent with accurate calculations, which reveal that the quadrupolar picture is qualitatively wrong. At typical π-stacking distances, quadrupolar electrostatics may differ in sign from an exact calculation based on charge densities of the interacting arenes.
View Article and Find Full Text PDFMethods Mol Biol
January 2025
Biomic Auth, Bioanalysis and Omics Laboratory, Center for Interdisciplinary Research and Innovation, Aristotle University, Thessaloniki, Greece.
Metabolomics aims at identification and quantitation of key end point metabolites, basically polar, in order to study changes in biochemical activities in response to pathophysiological stimuli or genetic modifications. Targeted profiling assays enjoying a growing popularity over the last years with LC-MS/MS as a powerful tool for development of such (semi-)quantitative methods for a large number of metabolites. Here we describe a method for absolute quantitation of ca.
View Article and Find Full Text PDFJ Ethnopharmacol
January 2025
College of Pharmacy, Anhui University of Chinese Medicine, Hefei, 230012, Anhui, China; Institute of Pharmaceutics, Anhui Academy of Chinese Medicine, Hefei, 230012, Anhui, China; MOE-Anhui Joint Collaborative Innovation Center for Quality Improvement of Anhui Genuine Chinese Medicinal Materials, Hefei, 230012, Anhui, China; Anhui Engineering Research Center for Quality Improvement and Utilization of Genuine Chinese Medicinal Materials, Hefei, 230012, Anhui, China; Center for Xin'an Medicine and Modernization of Traditional Chinese Medicine of IHM, Anhui University of Chinese Medicine, Hefei, 230012, Anhui, China. Electronic address:
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