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991.
This paper presents data on adsorption of immunogamma globulin (IgG) onto synthetic rodlike calcium hydroxyapatite particles (CaHaps) with various particle lengths and calcium/phosphate (Ca/P) atomic ratios ranging from 1.54 to 1.65 and compares the obtained results to those of acidic (bovine serum albumin, BSA), neutral (myoglobin, MGB), and basic (lysozyme, LSZ) proteins reported before. The effect of electrolyte concentration on IgG adsorption was also examined. The initial rate of IgG adsorption was similar to that of BSA and was slower than that of MGB and LSZ. This fact was interpreted by the difference in the structural stability and molecular weight of these proteins. The isotherms of IgG adsorption onto the CaHap particles were of pseudo-Langmuir type. The saturated amount of adsorbed IgG values (nsIgG) for the particles with mean particle length less than 70 nm decreased with increasing Ca/P ratio. The adsorption behavior of IgG molecules was very similar to that of basic LSZ, though IgG has zero net charge. The nsIgG value was increased with increased mean particle length of CaHaps; the relationship was less significant than that for BSA but similar to those for MGB and LSZ. The similar adsorption behavior of IgG and LSZ suggested that the Fab parts of IgG molecules preferentially adsorb onto CaHap to provide the reversed Y-shaped conformation of IgG. The change of the adsorption mode of IgG molecules from the reversed Y-shaped conformation to side-on by "spreading" the Fc part of IgG molecules onto the particle surface over a longer adsorption time was suggested. The nsIgG value was increased with increasing electrolyte concentration by screening the intra- and intermolecular electrostatic interactions of proteins. 相似文献
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995.
T.G. Appleton M.A. Bennett A. Singh T. Yoshida 《Journal of organometallic chemistry》1978,154(3):369-385
The reactions of various alkyne-platinum(0) complexes with methyl iodide and with iodine have been studied. The 3-hexyne complex Pt(C2H5C2C2H5)(PPh3)2 gives alkyne-free oxidative addition products PtI(CH3) (PPh3)2 and PtI2 (PPh3)2 exclusively. In contrast, the strained cyclic alkyne complexes Pt(C6H8)(PPh3)2, Pt(C7H10)(PPh3)2, Pt(C6H8) (dppe) and Pt(C7H10) (dppe)1 react with methyl iodide to give mainly 2-methylcycloalkenyiplatinum(II) complexes, e.g. PtI(C6H8CH3) (PPh3)2, formed by electrophilic attack on the metal-alkyne bond. Iodine reacts similarly with Pt(C6H8) (PPh3)2 and Pt(C7H10) (PPh3)2 to give 2-iodocycloalkenylplatinum(II) complexes but, in the case of the corresponding dppe complexes, PtI2(dppe) is the main product. The insertion reaction of methyl iodide with Pt(C6H8)(PPh3)2 proceeds via an oxidative addition intermediate PtI(CH3) (C6H8) (PPh3)2 which can be isolated. Trifluoromethyl iodide reacts with Pt(C6H8)(PPh3)2 to give a 2-iodocyclohexenyl complex Pt(CF3) (C6H8I) (PPh3)2 and with Pt(C7H10) (PPh3)2 to give PtI(CF3) (PPh3)2. 31P NMR data are given and discussed. 相似文献
996.
T. Kitagawa M. Abe Y. Kyogoku H. Ogoshi H. Sugimoto Z. Yoshida 《Chemical physics letters》1977,48(1):55-58
Resonance Raman spectra of 15N enriched metallooctaethylporphyrins [M(OEP) ? 15N4] [M = Ni2+, Fe3+ (high spin), and Fe3+ (low spin)] were observed. Polarized Raman lines corresponding to the oxidation state marker band of hemoproteins were observed at 1377 (Ni), 1369 (Fe high spin) and 1372?1 (Fe low spin) which were shifted to lower frequency from those of the 14N compounds by 6, 5, and 6 cm?1, respectively. The vibrational mode for this band was shown to include an appreciable contribution of the CαN symmetric stretching vibration and to be associated with ca. 0.01 Å of in-phase displacement of the four pyrrole nitrogens toward the metal ion. 相似文献
997.
Tomoaki Abe Tatsuo Suzuki Kazuhiko Sekiguchi Seijiro Hosokawa Susumu Kobayashi 《Tetrahedron letters》2003,44(52):9303-9305
Synthetically useful β,γ-unsaturated carbonyl compounds having a quaternary carbon at the -position were prepared with high stereoselectivity by the reaction of a dienolate anion derived from ,β-unsaturated imide having a chiral auxiliary and electrophiles (ethyl acetate and allyl iodide as the C2 and C3 unit, respectively). This method was applied to a short asymmetric synthesis of (+)-ethosuximide. 相似文献
998.
Jinhua Chen Yasunari Maekawa Masaru Yoshida Norio Tsubokawa 《Journal of Polymer Science.Polymer Physics》2002,40(1):134-141
A series of thermoresponsive polymer gel electrolytes (PGEs) based on poly(N‐isopropylacrylamide) in aqueous potassium chloride was synthesized by radiation‐induced polymerization and gelation using γ rays from a 60Co source. The electric conductivity and swelling properties of the PGE were determined as a function of temperature. It was found that the electric conductivity of the PGE depended strongly on the swelling ratio; most notably, it changed drastically near the volume phase‐transition temperature of the PGE. The temperature/conductivity profile of the PGE exhibits a maximum peak at a certain temperature that is defined as the maximum conductivity temperature (Tmax). The Tmax of all of the PGEs prepared by low‐dose irradiation agreed with the temperature, near the end of the volume phase transition, where the PGE was completely shrunken. Consequently, the conductivity of gels should provide a good method with which the totally shrunken temperature of the thermoresponsive gels can be monitored with good temperature precision. © 2001 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 40: 134–141, 2002 相似文献
999.
Matsunaga S Yoshida T Morimoto H Kumagai N Shibasaki M 《Journal of the American Chemical Society》2004,126(28):8777-8785
Full details of a direct catalytic asymmetric Mannich-type reaction of a hydroxyketone using a Et2Zn/(S,S)-linked-BINOL complex are described. By choosing the proper protective groups on imine nitrogen, either anti- or syn-beta-amino alcohol was obtained in good diastereomeric ratio, yield, and excellent enantiomeric excess using the same zinc catalysis. N-Diphenylphosphinoyl (Dpp) imine 3 gave anti-beta-amino alcohols in anti/syn = up to >98/2, up to >99% yield, and up to >99.5% ee, while Boc-imine 4 gave syn-beta-amino alcohols in anti/syn = up to 5/95, up to >99% yield, and up to >99.5% ee. The high catalyst turnover number (TON) is also noteworthy. Catalyst loading was successfully reduced to 0.02 mol % (TON = up to 4920) for the anti-selective reaction and 0.05 mol % (TON = up to 1760) for the syn-selective reaction. The Et2Zn/(S,S)-linked-BINOL complex exhibited far better TON than in previous reports of catalytic asymmetric Mannich-type reactions. Mechanistic studies to clarify the reason for the high catalyst efficiency as well as transformations of Mannich adducts are also described. 相似文献
1000.
Yoshikazu Suzuki Supachai Ngamsinlapasathian Ryuhei Yoshida Susumu Yoshikawa 《Central European Journal of Chemistry》2006,4(3):476-488
Partially nanowire-structured TiO2 was prepared by a hydrothermal processing followed by calcination in air. The hydrogen titanate powder as-synthesized was
calcined at 300 °C for 4 h to obtain the partially nanowire-structured TiO2. A dye-sensitized solar cell (DSC) with a film thickness of 5.6 μm, fabricated using the partially nanowire-structured TiO2 showed better performance than using a fully nanowire-structured TiO2 or a conventional equi-axed TiO2 nanopowder. The short-circuit current density (JSC), the open-circuit voltage (VOC), the fill factor (FF) and the overall efficiency (η) are 11.9 mA/cm2, 0.754 V, 0.673 and 6.01 %, respectively. The effects of one-dimensional nanostructure and electron expressway concept are
discussed. 相似文献