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Molecules Only (molecule + only)
Selected AbstractsOne-bond 13C,13C coupling constants in alkyl-substituted cyclopropenes: experimental and theoretical studies,MAGNETIC RESONANCE IN CHEMISTRY, Issue 10 2002Krystyna Kamie, ska-Trela Abstract Measurements of one-bond carbon,carbon coupling constants, 1J(C, C), were performed for two series of compounds, alkyl-substituted cyclopropenes and cyclopropanes. The experimental data were complemented by a set of DFT-calculated J couplings for the parent cyclopropene (1), its methyl and silyl derivatives and, additionally, for 1-methylcyclobutene (3), 1-methylcyclopentene (4) and 1-methylcyclohexene (5) and good agreement was observed between the experimental and the calculated data; all the trends are perfectly maintained, including a dramatic decrease in the couplings across endocyclic single bonds in cyclopropene and its derivatives, and a significant decrease in the corresponding couplings in cyclobutene. Using the data obtained, the s characters of the carbon hybrid orbitals involved in the formation of the cyclopropene were calculated. The results clearly show that the ring closure and the related strain exerted upon the cyclopropene molecule only slightly disturb the electron structure of the double bond. The s character of the corresponding carbon orbital is 0.314 in cyclopropene vs the theoretical value of 0.333 in ethene. This is at variance with the endo- and exocyclic single bonds, where the s characters of the orbitals forming the endocyclic single bonds are much smaller than those of the bonds in the open-chain compounds, i.e. 0.229 (C-1 and/or C-2) and 0.166 (C-3). The s values calculated for the exocyclic CH bonds are 0.334 for C-3 and 0.456 for C-1 and/or C-2. Copyright © 2002 John Wiley & Sons, Ltd. [source] IL-33 promotes DC development in BM culture by triggering GM-CSF productionEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 12 2009Nobuyasu Mayuzumi Abstract Short-term DC cultures generated with GM-CSF and other cytokines have markedly improved our ability to study the immunobiology of DC. Here, we tested 65 cytokines individually for their potential to promote the generation of CD11c+ cells in a murine BM culture system. In addition to several cytokines known to promote DC survival and/or growth, IL-33 was found to augment DC development time- and dose-dependently. Although the resulting CD11c+ cells generated in the presence of IL-33 exhibited a typical dendritic morphology, they expressed MHC class II molecules only at modest levels, showed negligible responses to TLR ligands, produced no detectable IL-12 p70, displayed PD-L1 and PD-L2 on the surface, and failed to activate immunologically naïve T cells efficiently. IL-33-induced expansion of CD11c+ cells was completely blocked by anti-GM-CSF mAb, and GM-CSF mRNA and protein expression in BM culture was markedly elevated by added IL-33, indicating that IL-33 promotes in vitro DC generation indirectly by a GM-CSF-dependent manner. With regard to the cellular source, IL-33-dependent GM-CSF production was observed exclusively within the CD45+/Fc,RI+ BM population. Not only do our results reinforce the notion that GM-CSF serves as a primary DC growth factor, but they also reveal a previously unrecognized mechanism supporting DC development. [source] Multianalyte immunoassay based on surface-enhanced Raman spectroscopyJOURNAL OF RAMAN SPECTROSCOPY, Issue 7 2007Yan Cui Abstract In this paper, two immunoassay methods based on SERS are developed for multiplex analysis, both of which stemmed from the concept of forming a sandwich structure ,capture antibody substrate/antigen/Raman-reporter-labeled immuno-nanoparticles'. They are two-molecule labeled one-nanoparticle and one-molecule labeled two-nanoparticle methods. In both the methods, two different antibodies covalently bound to a solid substrate can specifically capture two different antigens from a sample. The captured antigens in turn bind selectively to their corresponding antibodies immobilized on Raman-reporter-labeled nanoparticles. Multianalyte immunoassay is successfully demonstrated by the detection of characteristic Raman bands of the probe molecules only when the antigen and antibody are matched. Copyright © 2007 John Wiley & Sons, Ltd. [source] HD in the primordial gasMONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 3 2000D. R. Flower We study the role of HD in the thermal balance of the primordial gas, beyond the redshift, z, at which the temperatures of radiation and matter have decoupled (z , 300). Statistical arguments are used to derive the rate constants for the forward and reverse reactions, D+(H2, HD)H+, involving reactant and product molecules in excited rotational states. The degree of chemical fractionation of HD is enhanced, compared with the value calculated by taking account of reactions between ground-state molecules only, by a factor of about 2. In spite of its low abundance (10,3), relative to H2, HD contributes comparably to the rate of heating of the gas, through rotationally inelastic collisions with H and He. The much larger rate coefficients for collisional population transfer within HD, compared with H2, and the tighter rotational level spacing are responsible for this finding. We conclude that HD is about as important as H2 in the thermal balance of the primordial gas. [source] | ||||||||||