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Homologous Compounds (homologous + compound)
Selected AbstractsNew variants of polar glycopeptidolipids detected in Mycobacterium simiae, including ,habana' strains, as evidenced by electrospray ionization-ion trap-mass spectrometryJOURNAL OF APPLIED MICROBIOLOGY, Issue 2 2008L. Mederos Abstract Aims:, To determine the composition of polar glycopeptidolipids (pGPLs) of Mycobacterium simiae and, particularly, those of ,habana' strains, in a search for specific markers given the immunogenic potential of ,habana' TMC 5135 in experimental tuberculosis. Methods and Results:, pGPLs were determined in free lipid extracts using electrospray ionization-ion trap-mass spectrometry (ESI-IT-MS), working in both negative- and positive-ion mode. In the case of TMC 5135, the presence of the previously characterized GPL-II (containing 2,4-di-O-CH3 glucuronic acid as distal sugar in the oligosaccharide antigenic moiety) and GPL-III (containing 4-O-CH3 glucuronic acid as distal sugar) was confirmed using MS/MS and MS/MS/MS approaches. Interestingly, some ,habana' strains presented variants of GPL-II, designated GPL-II,-A and GPL-II,-B. A di-O-CH3 -deoxy-hexose (tentatively, 2,3-di-O-CH3 -fucose) was identified as the penultimate sugar in the oligosaccharide moiety of GPL-II,-A, whereas in GPL-II,-B the penultimate sugar was fucose (tentative identification). On the contrary, the distal sugar of the oligosaccharide chain of pGPLs of Myco. simiae ATCC 25275T was identified as tri-O-CH3 -glucuronic acid (designated GPL-simT -I, with two variants: GPL-simT -I-A and GPL-simT -I-B), O-CH3 -glucuronic acid (designated GPL-simT -II) and di-O-CH3 -glucuronic acid (GPL-II,-A and GPL-II,-B). The penultimate sugar of the oligosaccharide chain of GPL-simT -I-A and GPL-simT -II was identified as di-O-CH3 -deoxy-hexose (tentatively, 2,3-di-O-CH3 fucose), and that of GPL-simT -I-B as deoxy-hexose (tentatively, fucose). In all strains studied, each [M-H], and [M+Na]+ ion was revealed as a mixture of homologous compounds varying in the number of ,O-CH3 groups present in the oligosaccharide moiety and in the length of the fatty acyl linked to the peptide. Conclusions:, The present work indicates that, within a similar general pattern of pGPLs, different strains of Myco. simiae present some variations, so that new compounds (GPL-II,-A, GPL-II,-B, GPL-simT -I-A, GPL-simT -I-B and GPL-simT -II) were defined. Noteworthy was the fact that the ,habana' strains clearly differed from the type strain of Myco. simiae. Significance and Impact of the Study:, The data obtained can be used in the delineation of the ,habana' group of Myco. simiae, including the quality control of the immunogenic strain ,habana' TMC 5135. [source] Collision-induced dissociation of sulfur-containing imidazolium ionic liquidsJOURNAL OF MASS SPECTROMETRY (INCORP BIOLOGICAL MASS SPECTROMETRY), Issue 1 2008Alain Lesimple Abstract A number of 1,2-dimethylimidazole ionic liquids substituted on NII with alkyl chains of varying lengths terminated with sulfur-containing groups were investigated by electrospray high-resolution tandem Fourier-transform mass spectrometry. Fragmentation pathways are strongly dependent on the oxidation state of the sulfur and the alkyl chain length. The dissociations detected are rationalized by deuterium labeling, comparisons between homologous compounds and accurate mass data. Several homolytic processes are reported, leading to distonic ions and loss of hydrogen, methyl and other free radicals. Copyright © 2007 John Wiley & Sons, Ltd. [source] Vibrational and optical properties of a one-dimensional organic,inorganic crystal [C6H14N]PbI3JOURNAL OF RAMAN SPECTROSCOPY, Issue 7 2008S. Elleuch Abstract Self-assembled organic,inorganic [C6H14N]PbI3 crystals were synthesized. The crystal structure consists of one-dimensional semiconductor chains formed by infinite PbI6 face-sharing octahedra aligned along the a -axis. The organic cations are linked to the inorganic chains by NH· · ·I hydrogen bonds and act as insulator barriers. The vibrational properties of [C6H14N]PbI3 were studied using polarized Raman scattering and infrared (IR) absorption. The observed Raman and IR spectral features were identified by comparison with the vibrational properties of homologous compounds and with the vibrational wavenumbers calculated using the ab initio PM3 method. Moreover, the photoluminescence and diffuse reflectance of [C6H14N]PbI3 single crystals, along with the UV-Vis absorption of spin- coated films, were measured. A strong green-blue luminescence due to radiative recombinations of 1D excitons is observed. The Stokes shift is estimated at 70 meV. Copyright © 2008 John Wiley & Sons, Ltd. [source] Subsolidus Phase Relationships in the ZnO,In2O3,SnO2 SystemJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 11 2008Steven P. Harvey The subsolidus phase relationships in the ZnO,InO1.5,SnO2 system were investigated at 1275°C using X-ray diffraction. Each of the end members of the ternary diagram is a transparent conducting oxide. There are two substantial solid solutions in the ternary phase space, the bixbyite solid solution In2,2xZnxSnxO3 (x=0,0.40), and the indium substituted zinc stannate spinel, Zn(2,x)Sn(1,x)In2xO4 (x=0,0.45). The bixbyite solid solution is an outstanding TCO, whereas the spinel is only moderately conducting. Along the ZnO,InO1.5 binary, there is a series of transparent conducting homologous compounds (ZnO)k·In2O3 (where k=3, 4, 5, 6, 7, 9, 11). Within ternary phase space, these homologous compounds were found to exhibit negligible Sn solubility, and were always found to be compatible with the spinel. Equilibrium was difficult to achieve in the phase space between the homologous series compounds and the spinel, owing to sluggish kinetics. A procedure involving mixtures of prereacted spinel and the Zn11In2O14 (k=11) compound was developed, which allowed for more rapid approach to thermodynamic equilibrium, thereby allowing for the establishment of phase relationships near the ZnO corner of the phase diagram. [source] | ||||||||||