1,720,984 research outputs found
Ring contraction reactions in cyclooctatetraene oxide catalyzed by transition metals
No full textThe ring contraction of cyclooctatetraene oxide (COTEO) catalyzed by transition metal compounds is reported. The organic intermediates have been characterized and stabilization of the liable cycloheptatrienealdehyde in the presence of a copper salt is reported. © 1974
Effect of Methyl Substituents on the NMR Spectra of Aromatic Protons of Some Nitrobenzene Derivatives
No full textProton NMR spectra were recorded and analysed for 1‐bromo‐4‐nitrobenzene, 2‐bromo‐5‐nitroluene, 3‐bromo‐6‐nitrotoluene and 2‐bromo‐5‐nitro‐p‐xylene, as well as for the corresponding compounds having p‐CH3C6H4S in place of Br. Chemical shifts and coupling constants generally agree with expected values; however, a deshielding effect of the methyl group on aromatic protons was observed in one case
19F- nuclear magnetic relaxation by superoxide dismutase as an enzymic method for the detection of superoxide ion
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Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Electrostatic control of the rate-determining step of the copper, zinc, superoxide dismutase catalytic reaction
No full text19F relaxation as a probe of the oxidation state of Cu, Zn superoxide dismutase. Studies of the enzyme in steady-state turnover
No full text19F nmr relaxation proved to be a proper method to evaluate the Cu2+/Cu+ ratio at the active site of Cu, Zn superoxide dismutase in either equilibrium or turnover conditions. In the steady-state under fluxes of O2-, the enzyme was found to contain 50% Cu2+, in accord with the equal rates of copper catalytic reduction and oxidation. Previous results giving 75% Cu at the steady-state without change of the overall catalytic constant were confirmed for samples subjected to freeze-drying or freezing-thawing. © 1981 Academic Press, Inc
Reaction of dithionite with nitroxides. A new possible spin trapping agent of superoxide ion
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