A new synthesis of trifluorinated compounds via 1,1-dichloro-1-alkenes in superacid

A two step process for converting ketone or aldehyde via 1,1-dichloro-1-alkenes to the corresponding 1,1,1-trifluoroderivatives is described, based on HF addition and chlorine-fluorine exchange under superacidic conditions.     

Zinc porphyrin sensitized redox processes in microemulsions

Photoinduced electron transfer from Zn tetraphenylporphyrin to acceptors solubilized either in the lipid interior or aqueous bulk of anionic oil-in-water microemulsions has been investigated by nanosecond laser photolysis. While intimate cosolubilization appears to decrease the efficiency of electron transfer in the former, enhanced charge separation of the redox products has been observed in the latter.     

Quasi sure analysis and Stratonovich anticipative stochastic differential equations

Summary Consider a stochastic differential equation on ^d with smooth and bounded coefficients. We apply the techniques of the quasi-sure analysis to show that this equation can be solved pathwise out of a slim set. Furthermore, we can restrict the equation to the level sets of a nondegenerate and smooth random variable, and this provides a method to construct the solution to an anticipating stochastic differential equation with smooth and nondegenerate initial condition.     

Dérivés Alléniques du Phosphore. Influence de l'État de Coordination du Phosphore et de la Nature des Radicaux Liés au Phosphore sur les Signes de J(P?H)

The signs of the phosphorus-proton coupling constants in various allenic organophosphorus compounds have been determined by either analysis of the AB₂X spectra or double resonance. Probable absolute signs have been obtained by taking ³J(P? H) as positive. In allenic phosphine oxides, the following signs are obtained: ²J(P? H) +ve, ³J(P? H) +ve, ⁴J(P? H) ?ve, ⁵J(P? H) +ve and the ⁴J(P? H) coupling constant varies mostly with the inductive effect of the substituents bound to the phosphorus atom. In allenic phosphines, these sings are: ²J(P? H) +ve, ³J(P? H) +ve, ⁴J(P? H) ?ve and +ve and the ⁴J(P? H) coupling constant varies with both the inductive and resonance effects to the substituents. This coupling constant is negative except when the phosphorus atom is bound to groups which are electron-donating by resonance effects. These results are discussed in relation to the pπ? dπ bonding in phosphine.     

The biologically important surfactin lipopeptide induces nanoripples in supported lipid bilayers

Under specific conditions, lipid membranes form ripple phases with intriguing nanoscale undulations. Here, we show using in situ atomic force microscopy (AFM) that the biologically important surfactin lipopeptide induces nanoripples of 30 nm periodicity in dipalmitoyl phosphatidylcholine (DPPC) bilayers at 25 degrees (i.e. well below the pretransition temperature of DPPC). Whereas most undulations formed the classical straight orientation with characteristic angle changes of 120 degrees , some of them also displayed unusual circular orientations. Strikingly, ripple structures were formed at 15% surfactin but were rarely or never observed at 5 and 30% surfactin, emphasizing the important role played by the surfactin concentration. Theoretical simulations corroborated the AFM data by revealing the formation of stable surfactin/lipid assemblies with positive curvature.     

2D silver nanocrystal ordering modulated by various substrates and revealed using oxygen plasma treatment

Here, 5 nm Ag nanocrystals are deposited, using the same procedure, on various substrates differing by their rms roughness, wetting properties and nanoparticle-substrate interactions leading, consequently, to different nanocrystal orderings. Theoretical calculations are carried out to understand how these parameters influence the size of the nanocrystal organizations on the substrate surface. When these nanocrystal arrays are subjected to an oxygen plasma treatment, the nanocrystals perfectly assembled in hexagonal networks remain intact, while the nanocrystals that are not well-packed coalesce to form larger particles independently on the used substrate. This phenomenon is observed on the entire substrate surface. This procedure gives an innovative way of using oxygen plasma generated by the reactive ion etching technique, as a new method to reveal defects in 2D Ag nanocrystal self-assemblies.     

Invariant or quasi-invariant probability measures for infinite dimensional groups

Some infinitesimal representations of Virasoro algebra are known to be unitarizable; is it possible to realize the underlying Hilbert space as an L ²-space?     

Quasi-invariance of Brownian measures on the group of circle homeomorphisms and infinite-dimensional Riemannian geometry

A Cameron-Martin-type theorem is proved for the canonical Brownian motion on the group of homeomorphisms of the circle.