New directions for the Morita-Baylis-Hillman reaction; homologous aldol adducts via epoxide opening

Under trialkylphosphine catalyzed Morita-Baylis-Hillman reaction conditions, epoxides react with enones to give rise to homologous aldol adducts.     

CO- and N2-FTIR characterisation of oxidised Rh species supported on Ce0.68Zr0.32O2

The identification of a Rh-oxidised species of a Rh(0.29)/Ce0.68Zr0.32O2 catalyst that exhibits peculiar CO-O2 kinetics [I. Manuel, J. Chaubet, C. Thomas, H. Colas, N. Matthess and G. Djéga-Mariadassou, J. Catal. 2004, 224, 269] is addressed. For this purpose, various catalysts are studied by XANES, CO- and N2-FTIR, and benzene hydrogenation. The results obtained, particularly from N2-FTIR, which is, to our knowledge, reported for the first time on this kind of catalyst, suggest that Rh is mainly stabilised as electron-deficient clusters (Rhndelta+) on a Rh(0.29)/Ce0.68Zr0.32O2 catalyst after reduction at 500 degrees C under H2. The existence of these species, which may be caused by either electron perturbation induced on the metal by the reduced support or electron withdrawal from the metal clusters by an inductive effect of the neighbouring Cl anions, is also revealed through CO-FTIR experiments. In the presence of CO, however, evidence of RhI(CO)2 species is also provided.     

Eine Vorrichtung zur Destillation im Hochvakuum

Ohne Zusammenfassung     

Über ein Eulersches Verfahren zur Wurzelberechnung

Ohne Zusammenfassung     

The numerical integration of relative equilibrium solutions. The nonlinear Schrodinger equation

We analyse different error propagation mechanisms for conservativeand nonconservative time-integrators of nonlinear Schrödingerequations. We use a geometric approach based on interpretingwaves as relative equilibria.     

Perfluorocarbons: Life sciences and biomedical uses Dedicated to the memory of Professor Guy Ourisson,a true RENAISSANCE man.

Perfluorocarbons are primarily characterized by outstanding chemical and biological inertness, and intense hydrophobic and lipophobic effects. The latter effects provide a powerful noncovalent, labile binding interaction that can promote selective self‐ assembly. Perfluoro compounds do not mimic nature, yet they can offer abiotic building blocks for the de novo design of functional biopolymers and alternative solutions to physiologically vital issues. They offer new tags useful for molecular recognition, selective sorting, and templated binding (e.g., selective peptide and nucleic acid pairing). They also stabilize membranes and provide micro‐ and nanocompartmented fluorous environments. Perfluorocarbons provide inert, apolar carrier fluids for lab‐on‐a‐chip experiments and assays using microfluidic technologies. Low water solubility, combined with high vapor pressure, allows stabilization of injectable microbubbles that serve as contrast agents for diagnostic ultrasound imaging. High gas solubilities are the basis for an abiotic means for intravascular oxygen delivery. Other biomedical applications of fluorocarbons include lung surfactant replacement and ophthalmologic aids. Diverse colloids with fluorocarbon phases and/or shells are being investigated for molecular imaging using ultrasound or magnetic resonance, and for targeted drug delivery. Highly fluorinated polymers provide a range of inert materials (e.g., fluorosilicons, expanded polytetrafluoroethylene) for contact lenses, reconstructive surgery (e.g., vascular grafts), and other devices. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 1185–1198, 2007.     

Oblique electron-beam injection into plasma: effect of externalmagnetic field upon gun environment

When injecting an electron beam with a significant pitch-angle in a magnetoplasma, one has to take care that the parallel velocity of the electrons measured in the plasma does not only depend on the acceleration potential between the anode and the cathode of the electron gun, but also on the amplitude of the ambient magnetic field. The latter can play an important role when the actual acceleration distance of electrons in the gun vicinity, determined partly by collective processes that lead to potential modification in the gun environment, is large enough. Consequently, the actual beam pitch-angle can be noticeably different from the orientation of the electron gun     

A Nonpolar,Nonamphiphilic Molecule Can Accelerate Adsorption of Phospholipids and Lower Their Surface Tension at the Air/Water Interface

The adsorption dynamics of a series of phospholipids (PLs) at the interface between an aqueous solution or dispersion of the PL and a gas phase containing the nonpolar, nonamphiphilic linear perfluorocarbon perfluorohexane (PFH) was studied by bubble profile analysis tensiometry. The PLs investigated were dioctanoylphosphatidylcholine (DiC₈‐PC), dilaurylphosphatidylcholine, dimyristoylphosphatidylcholine, and dipalmitoylphosphatidylcholine. The gas phase consisted of air or air saturated with PFH. The perfluorocarbon gas was found to have an unexpected, strong effect on both the adsorption rate and the equilibrium interfacial tension (γ_eq) of the PLs. First, for all of the PLs, and at all concentrations investigated, the γ_eq values were significantly lower (by up to 10 mN m^?1) when PFH was present in the gas phase. The efficacy of PFH in decreasing γ_eq depends on the ability of PLs to form micelles or vesicles in water. For vesicles, it also depends on the gel or fluid state of the membranes. Second, the adsorption rates of all the PLs at the interface (as assessed by the time required for the initial interfacial tension to be reduced by 30 %) are significantly accelerated (by up to fivefold) by the presence of PFH for the lower PL concentrations. Both the surface‐tension reducing effect and the adsorption rate increasing effect establish that PFH has a strong interaction with the PL monolayer and acts as a cosurfactant at the interface, despite the absence of any amphiphilic character. Fitting the adsorption profiles of DiC₈‐PC at the PFH‐saturated air/aqueous solution interface with the modified Frumkin model indicated that the PFH molecule lay horizontally at the interface.