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71.
72.
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
73.
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
74.
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
75.
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
76.
Compound 1, a cryptand-derived macropentacycle, is a flexible molecule that encompasses many conformations (symmetrical, unsymmetrical, and chiral ones) depending on the observation temperature (VT 1H NMR). Selective monoprotonation of this molecule leads to a totally unsymmetrical, rigidly chiral species in solution (1H NMR). Helical chirality and in-out conformation of monoprotonated 1 are observed in the solid state by X-ray diffraction analysis, as well as the proton location. The latter is bound to the endo bridgehead nitrogen atom and involved in hydrogen-bonding interactions with the three closest sulfurs. Significant induction of chirality is triggered by reaction of 1 with the optically active (R)-(-)-1,1'-binaphthyl-2,2'-diylphosphoric acid. It proceeds with a maximum 24% diastereomeric excess, as shown by the splitting, in the 62:38 intensity ratio, of several 1H NMR signals. These correspond to the two indistinguishable diastereomeric ion pairs: (Lambda-[1-H])((R)-(-)-BNP) and (Delta-[1-H])((R)-(-)-BNP). 相似文献
77.
Bucher C Moutet JC Pécaut J Royal G Saint-Aman E Thomas F 《Inorganic chemistry》2004,43(13):3777-3779
The Cu(I) and Cu(II) complexes of the new 1,8-diferro-cenylmethyl-4,11-dimethyl-1,4,8,11-tetraazacyclotetra-decane ligand (denoted L) have been isolated and characterized by X-ray structure determination and electrochemical studies. The Cu(I) complex presents an unprecedented stability toward dioxygen. The two complexes adopt two energetically distinct and stable geometries, which differ mainly by the relative positioning of the substituents above or below the cyclam plane. Triggered by a copper-centered electron transfer, a fast and reversible motion of the noncoordinating subunits is obtained in homogeneous solution and in the solid state. 相似文献
78.
Dynamic arsenic removal on a MnO2-loaded resin 总被引:2,自引:0,他引:2
Lenoble V Chabroullet C al Shukry R Serpaud B Deluchat V Bollinger JC 《Journal of colloid and interface science》2004,280(1):62-67
Previous batch studies on a polystyrene matrix loaded with manganese dioxide, synthesized from an anionic commercial resin in chloride form, have proven the efficiency of this sorbent in As(V) and As(III) removal. This solid is now tested with column experiments to predict its behavior in a treatment process. An artificial water, with a composition in major ions similar to that of granitic water, often contaminated with arsenic, was prepared. This artificial water was used to simulate arsenic removal processes under near-natural conditions and with a stable composition. Furthermore, the hydride generation AAS analytical method was optimized to measure low arsenic concentrations (1 to 20 microg/L). 相似文献
79.
Yves Fé lix Jean-Claude Thomas 《Proceedings of the American Mathematical Society》2004,132(1):305-312
Let be a simply-connected closed oriented -dimensional manifold. We prove that for any field of coefficients there exists a natural homomorphism of commutative graded algebras where is the loop algebra defined by Chas and Sullivan. As usual denotes the monoid of self-equivalences homotopic to the identity, and the space of based loops. When is of characteristic zero, yields isomorphisms where denotes the Hodge decomposition on .
80.
Dablemont C Proust A Thouvenot R Afonso C Fournier F Tabet JC 《Inorganic chemistry》2004,43(11):3514-3520
Reaction of [Bu(4)N](4)[H(3)PW(11)O(39)] with [Re(NPh)Cl(3)(PPh(3))(2)], in acetonitrile and in the presence of NEt(3), provided the first Keggin-type organoimido derivative [Bu(4)N](4)[PW(11)O(39)(ReNPh)] (Ph = C(6)H(5)) (1). The functionalization was clearly demonstrated by various techniques including (1)H and (14)N NMR, electrochemistry, and ESI mass spectrometry. Conditions for the formation of 1 are also discussed. 相似文献