Asymmetric sulfur ylide mediated aziridination: application in the synthesis of the side chain of taxol

[reaction: see text] Sulfur ylide methodology has been used to construct the Taxol side chain with a high degree of enantioselectivity via a trans-aziridine followed by stereospecific rearrangement of the trans-benzoylaziridine into a trans-oxazoline.     

Derivations as square roots of Dirichlet forms

The aim of this work is to analyze the structure of a tracially symmetric Dirichlet form on a -algebra, in terms of a killing weight and a closable derivation taking values in a Hilbert space with a bimodule structure. It is shown that the generator of the associate Markovian semigroup always appears, in a natural way, as the divergence of a closable derivation. Applications are shown to the decomposition of Dirichlet forms and to the construction of differential calculus on metric spaces.     

Development of a capillary zone electrophoresis method for caseinoglycomacropeptide determination

Caseinoglycomacropeptide (CGMP) is a polypeptide of 64 amino acid residues, derived from the C-terminal part of bovine κ-casein. A sensitive and selective capillary zone electrophoresis method has been developed and validated for the analysis and quantitation of CGMP. Separation is carried out at 30 kV, using an uncoated fused-silica capillary and 20 mM sodium citrate buffer at acidic pH 3.5. The described method allows the separation of various CGMP subcomponents. The validation data proves that the method has the requisite selectivity, sensitivity, reproducibility and linearity for CGMP assay and for quality control during CGMP manufacturing (batch-to-batch reproducibility).     

Le Nullstellensatz de Hilbert et les polynômes à valeurs entières

We extend Hilbert's Nullstellensatz by replacing the fieldK by an integral domainA and the polynomial ringK[X ₁,...,X _n ] by the ring of integral-valued polynomials with respect toA. Necessary and sufficient conditions onA are given so that this generalized version holds.     

Finite-range DWBA analysis of (p, α) reactions on Be and B

The ground state angular distributions of the reactions ⁹Be(p, α)⁶Li and ¹¹B(p, α)⁸Be are analyzed by means of the DWBA theory. One-step direct mechanisms only are considered, but for both reactions the inclusion of the heavy-particle pick-up is found to be essential. DWBA fits to the data are obtained (a) in the zero-range approximation, (b) in the “fixed-range” approximation and (c) by an exact finite-range calculation. Only the latter method yields both an acceptable fit and reasonable values for the spectroscopic factors.     

Organic/metal interfaces in self-assembled monolayers of conjugated thiols: A first-principles benchmark study

We present an extensive theoretical study of a self-assembled monolayer of a prototype π-conjugated thiol on Au(1 1 1). A series of experimentally accessible quantities are calculated and compared to available experimental data. After assessing the methodology and re-evaluating experimental data in the light of our theoretical results, we focus on the interfacial phenomena determining the modification of the effective workfunction of the substrate and link our findings to the energetic alignment of the frontier molecular orbitals with the metal Fermi level. Since we find no evidence of charge transfer between metal and molecule, the observed interfacial phenomena are rationalized in terms of charge fluctuations and electrostatics at the atomic length scale. The microscopic picture established in this work provides a deeper understanding of the interfacial processes that govern the working principle of single-molecule electronics and organic electronic devices.     

A propos de l'existence et de la régularité des solutions de certaines inéquations quasi-variationnelles

We prove existence and regularity results for a general inequality including fixed point problems, variational and quasi variational inequalities. Examples of such problems are considered.     

Convergence of convex integrals in Lp spaces

We consider functionals of the form: I_f(u) = ∝_Tf[t, u(t)]μ(dt), which are defined on spaces L^p(T, R^k), and we study for these functionals the properties of a convergence for which the conjugacy $\text{I}{}_{\mathrm{f}}\text{→ I}{}_{\mathrm{f1}}$ is a continuous operator.