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排序方式: 共有1006条查询结果,搜索用时 15 毫秒
981.
Y. Sakuma K. Matsuoka C. Honda K. Matsumoto K. Endo 《Journal of Radioanalytical and Nuclear Chemistry》2008,277(3):591-594
The dynamics of redox related elements (Fe, Co, Zn, and Se) were studied using instrumental neutron activation analysis as
a function of rat age in the range of 4 to 16 weeks. Activity levels of glutathione peroxidase (GSH-Px), thiobarbituric acid
reactive substance (TBARS) were assayed, and hydrogen peroxide (H2O2) concentrations were measured for the same liver homogenates using an X-band ESR spectrometer. The oxidative stress, the
aging effect, and the mineral valance are discussed. 相似文献
982.
Takashi Kamegawa Masaya Matsuoka Masakazu Anpo 《Research on Chemical Intermediates》2008,34(4):427-434
A highly dispersed Cr6+-oxide species on silica (Cr/SiO2) was found to act as an efficient photocatalyst for the selective oxidation of CO into CO2 with O2 in the presence of H2 under visible (λ>420 nm) or solar light irradiation at 293 K. UV-Vis, photoluminescence and FT-IR investigations revealed
that the selective reactivity of the photoexcited tetrahedral Cr6+-oxide species ([Cr5+−O−]*) with CO, as well as the high reactivity of the photoreduced Cr6+-oxide species (Cr4+-oxide species) with O2 both play significant roles in this reaction. 相似文献
983.
We report enhanced second harmonic generation from nanostructured multilayers in combination with nonlinear optical polymer nanosheets and gold nanoparticles. 相似文献
984.
985.
A heterogeneous mono(phosphine)-Rh catalyst system silica-SMAP-Rh(OMe)(cod), where silica-SMAP stands for a caged, compact trialkylphosphine (SMAP) supported on silica gel, showed broad applicability toward the hydrogenation of hindered ketones. Doubly alpha-branched ketones such as diisopropyl ketone was hydrogenated under nearly atmospheric conditions. Di-tert-butyl ketone could be hydrogenated under more forcing conditions. 相似文献
986.
Ohgaru T Shimizu R Okamoto K Kawashita N Kawase M Shirakuni Y Nishikiori R Takagi T 《Journal of chemical information and modeling》2008,48(4):910-917
Conventional comparative molecular field analysis (CoMFA) requires at least 3 orders of experimental data, such as IC 50 and K i, to obtain a good model, although practically there are many screening assays where biological activity is measured only by rating scale. To improve three-dimensional quantitative structure-activity relationship (3D-QSAR) analysis, we developed in this study a modified ordinal classification-oriented CoMFA using partial-least-squares generalized linear regression and ridge estimation. The modified Logistic CoMFA was validated using a corticosteroid binding globulin receptor binding data set, a benchmark for 3D-QSAR, and an acetylcholine esterase inhibitor data set. Our results show that modification of Logistic CoMFA enhanced both prediction accuracy and 3D graphical analysis. In addition, the 3D graphical analysis of the modified Logistic CoMFA was much improved. This improvement resulted in more accurate information on the binding mode between proteins and ligands than in the case of conventional CoMFA. 相似文献
987.
Vukovi? J Matsuoka S Yoshimura K Juri?i? Grube?i? R Kremer D ?anti? N 《Analytical sciences》2012,28(4):397-402
A very sensitive, simple, and fast solid-phase spectrophotometric procedure for the determination of phenol using the p-nitrobenzenediazonium reagent (DAR reagent) was developed. This procedure is based on the simultaneous concentration of the orange product on a Dowex 1-X2 anion exchanger within 15 min, and a direct absorbance measurement of the sorbed species at both 530 nm (the absorption maximum of the phenol-DAR in the resin phase) and 700 nm (the range where only the resin absorbs light). Quality control and evaluation of the analytical parameters was carried out using a comprehensive prevalidation strategy. The linearity of the method was confirmed within an analyte working range from 0.01 to 0.10 μmol (0.2 to 2.0 nmol mL(-1)). The precision ranged from ±1.17 to ±9.61%; the accuracy ranged from -17.50 to +17.81%. The evaluated limiting values were L(D) = 0.0013 μmol and L(Q) = 0.0082 μmol. The DAR-SPS method was successfully applied to the determination of phenol in a pharmaceutical sample of salicylic acid (98.0-100.0%) and vaccines (98.0-103.4%). 相似文献
988.
A novel method for the selective determination of Fe(II) and Fe(III) in water using 2-nitroso-5-[N-n-propyl-N-(3-sulfopropyl)amino]phenol (PSAP) was developed. QAE-Sephadex anion exchanger packed in a flow-through cell was used as a medium not only for both the concentration and the spectrophotometric measurements of the Fe-PSAP complex, but also for reduction of the Fe(III)-PSAP complex. The PSAP complex of Fe(II) or Fe(III) was strongly adsorbed on the anion exchanger in a weakly acidic to weakly basic region, but the Fe(III) complex was readily and completely reduced to the Fe(II) complex only in a neutral to weakly alkaline region in the solid phase. These properties were utilized to determine the Fe(II) and total Fe concentration without the addition of any reducing agent. The detection limits (3σ) were 0.18 ng for Fe(II) and 0.18 ng for total Fe using a 3.2-cm(3) sample solution. The present method is applicable to the determination of dissolved iron species present at μg dm(-3) levels in natural water samples. 相似文献
989.
Maeki M Yamaguchi H Yamashita K Nakamura H Miyazaki M Maeda H 《Chemical communications (Cambridge, England)》2012,48(41):5037-5039
The single crystallization method by focusing on the characteristic internal fluid dynamics of the microdroplets was explored. Also the theoretical background was discussed, and the droplet size for obtaining only a single crystal within a microdroplet was estimated. 相似文献
990.
The first catalytic enantioselective conjugate addition of alkylboron compounds has been achieved. Reactions between alkylboranes and imidazol-2-yl α,β-unsaturated ketones proceeded with high enantioselectivity under the influence of a Cu(I) catalyst system, prepared in situ from CuCl, a new chiral imidazolium salt as a precursor for the N-heterocyclic carbene ligand, and PhOK. Alkylboranes are widely obtained via alkene hydroboration. A variety of functional groups are tolerated in alkylboranes and α,β-unsaturated ketones. 相似文献