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1.
A simple and efficient method for removal of phenolic methoxymethyl ethers in the presence of 30 mol% of bismuth trichloride in acetonitrile/water is described. Notable features of the cleavage protocol entail use of an ecofriendly bismuth reagent, ease of handling, low cost, operational simplicity, and good functional group compatibility. A number of structurally varied phenolic methoxymethyl ethers were cleaved in good to excellent yields.  相似文献   
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In this paper, novel results on the blue thermally stimulated luminescence (TSL) emission of ulexite (NaCaB5O6(OH)6·5H2O) have been studied. The four maxima appearing at 60, 110, 200 and 240°C on the TSL glow curves of this borate could be respectively associated to: (i) the first dehydration (NaCaB5O6(OH)6·5H2O→NaCaB5O6(OH)6·3H2O), (ii) the creation-annihilation of the three-hydrated phase, (iii) the Na-coordinated chains dehydroxylation and the starting point of the alkali self-diffusion through the lattice and (iv) the amorphisation of the lattice. These results are fairly well correlated with the differential thermal analyses (DTA), in situ thermal observations under environmental scanning electron microscope (TESEM) and thermal X-ray diffraction (TXRD) techniques.  相似文献   
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The total cross section as well as the differential cross section and polarization in the elastic scattering of 0.8–1.4 MeV neutrons by Y have been measured with neutron beams of energy spread less than 20 keV. Rather weak structure with widths ≈ 50 keV was observed at a few energies within this range. The data were analyzed by use of a model in which the scattering process is described in terms of resonance amplitudes superimposed on an optical-potential background. Although not completely definitive, this analysis indicates the existence of three intermediate-width resonances (two 1? and one 1+) at neutron energies between ≈ 1.0 and 1.2 MeV. The properties of the 1? resonances suggest that these are the parent states of the proposed T> components of the El giant resonance observed near 21 MeV excitation energy in 90Zr produced in the 89Y(p,γ0) reaction. The resolved resonance structure in this energy region is in reasonable agreement with a recent calculation of the energies and widths of negative-parity states in 90Y.  相似文献   
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New measurements of the dependence of the surface charge on the pH and electrolyte concentration for three living human white blood cell lines that are the principal targets of the HIV-1 virus are reported. Comparison of the electrophoretic fingerprint (EF) pattern, especially the line of zero mobility, with that of reference colloids establishes the separate individual identities and shows that all three exhibit a zwitterionic surface. With the EF results as a guide, preliminary biological infectivity measurements showed that small polyvalent cations modulate the negative charge on the T-cell surface in a way that strongly affects the infection kinetics. H9 cells were exposed to an infectious virus (X4), and the data showed that HIV interaction with target cells is enhanced by physiological fluids. The nondestructive methodology described is generally applicable to characterization of the surface charge and determination of the colloidal stability of any aqueous charged colloidal system without reference to any model of the double layer.  相似文献   
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In an effort to understand the formation of marine bioadhesives, mussel protein extracts were cured with various reagents and the enhanced cross-linking ability of Fe3+ was found.  相似文献   
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