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The activation parameters for the oxidation of 13 secondary alcohols with chromic acid have been determined. Application of a statistical treatment of Exner [9] shows that the reactions are isoentropic with an average entropy of activation (ΔS≠) of ?24.0 e. u. 相似文献
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Roselyne Briere Jean-Claude Espie René Ramasseul André Rassat Paul Rey 《Tetrahedron letters》1979,20(11):941-944
β-Ketoaldehyde derivatives of simple piperidine and pyrrolidine nitroxides as spin labelled ligands give paramagnetic three-electron copper complexes. 相似文献
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Jean-Claude Rivoal Jalal Shakhs Emampour Kyle J. Zeringue Martin Vala 《Chemical physics letters》1982,93(3):313-316
Peculiar transitions in the optical spectra of Mn atoms isolated in argon matrices confirm the existence of Mn2 molecule. The temperature variation of the absorption and MCD intensity in the range 13-27 K demonstrate that the Mn2 molecule is antiferromagnetic and allows a precise determination of its ground-state exchange energy: J = ?10.3 ± 0.6 cm?1. 相似文献
79.
In this Note we obtain existence and uniqueness results for the Helmholtz equation in the half-space with an impedance or Robin boundary condition. Basically, we follow the procedure we have already used in the bi-dimensional case (the half-plane). Thus, we compute the associated Green's function with the help of a double Fourier transform and we analyze its far field in order to obtain radiation conditions that allow us to prove the uniqueness of an outgoing solution. Again, these radiation conditions are somewhat unusual due to the appearance of a surface wave guided by the boundary. An integral representation of the solution is presented by means of the Green's function and the boundary data. To cite this article: M. Durán et al., C. R. Acad. Sci. Paris, Ser. I 341 (2005). 相似文献
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Birgitte Wuyts Dirk Bernard Nele Van Den Noortgate Johan Van De Walle Bruno Van Vlem Rita De Smet Frank De Geeter Raymond Vanholder Jean-Claude Libeer Joris Delanghe 《Accreditation and quality assurance》2004,10(1-2):15-19
When the calibration of a routine measurement procedure is traced back to metrological higher order, a significant discrepancy can occur between the analytical conditions of the routine measurement and the analytical conditions that were used in the clinical studies upon which the decision-making criteria are based. This can lead to serious interpretation errors with possible dramatic consequences for patients. The calibration of the creatinine Jaffé method is an excellent example of the importance of medical traceability. The compensated Jaffé method correlated accurately with the reference method and the compensated Jaffé creatinine clearance (CrCl), Cockroft and Gault and MDRD with the 51Cr EDTA clearance. The Schwartz estimate based upon the compensated Jaffé and enzymatic method overestimated, while uncompensated Jaffé slightly underestimated glomerular filtration rate (GFR). The situation in children is complex since serum creatinine concentrations are much lower in infants, rendering tubular secretion relatively more important. Low-molecular weight proteins have been suggested to replace serum creatinine as a marker for GFR. -trace protein, cystatin C, and 2-microglobulin showed good correlation with GFR. However, care should be taken in patients presenting with some malignant tumors, since significant increases of cystatin C in patients with metastatic melanoma or colorectal cancer has been reported.Presented at the 9th Conference on Quality in the Spotlight, 18-19 March 2004, Antwerp, Belgium 相似文献