Mixing for positive operators in Banach lattices

In this paper we extend M. Lin's definition of mixing for positive contractions in L₁(X,Σ,m) with m(X)=1 to positive operators in Banach lattices with weak-order units, and we generalize Lin's Theorem 2.1 (Z. Wahrsch. Verw. Gebiete 19 (1971) 231-249) to the case of power-bounded positive operators in KB-spaces. In the particular case of weakly compact power-bounded positive operators, the same theorem is extended to Banach lattices with order-continuous norms.     

Structural signature of a brittle-to-ductile transition in self-assembled networks

We study the nonlinear rheology of a novel class of transient networks, made of surfactant micelles of tunable morphology reversibly linked by block copolymers. We couple rheology and time-resolved structural measurements, using synchrotron radiation, to characterize the highly nonlinear viscoelastic regime. We propose the fluctuations of the degree of alignment of the micelles under shear as a probe to identify a fracture process. We show a clear signature of a brittle-to-ductile transition in transient gels, as the morphology of the micelles varies, and provide a parallel between the fracture of solids and the fracture under shear of viscoelastic fluids.     

Synthesis of halogenated 1-O-alkylglycerols from ricinoleic acid derivatives

Abstract

Resistance to the existing drugs and increasing numbers of diseases result in identifying new drug candidates with new forms of activity. As marine organisms are well known to provide a wide range of original compounds, Herein, we report the synthesis of new non-natural brominated, iodinated and chlorinated-substituted 1-O-alkylglycerols 5–7, analogs of a prominent 1-O-alkylglycerol (AKG) of the natural shark liver oil (SLO) mixture, namely the AKGs 18:1, n-9.     

Pr3 +–Yb3 +‐codoped lanthanum fluorozirconate glasses and waveguides for visible laser emission

Pr^3 +–Yb^3 +‐codoped fluoride glass waveguides have been synthesized by Physical Vapor Deposition (PVD). A study of the evaporation of ternary mixture of rare earth fluorides LaF₃–PrF₃–YbF₃ has been necessary to control the doping of the evaporated glass. Optical and spectroscopic studies have been performed in both bulk and waveguide configuration. Red, orange, green and blue emissions in Pr^3 +–Yb^3 +-codoped lanthanum flurozirconate glasses called ZLAG have been investigated, by exciting in the blue or in the infra-red at 980 nm. Bulk samples with different dopant concentrations (0.25–3 mol% for Pr^3 + and 0–5 mol% for Yb^3 +) have been studied in order to optimize the Pr^3 + emission. It has been shown than the luminescence is similar in bulk and waveguide upon excitation at 980 nm.     

A new access to 3-substituted-1(2H)-isoquinolone by tandem palladium-catalyzed intramolecular aminocarbonylation annulation

An original tribromide derivative based, palladium-catalyzed synthesis of 3-substituted-1(2H)-isoquinolone is described based on a regioselective Suzuki-Miyaura C-C coupling on o-halo-(2,2-dihalovinyl)-benzene followed by a palladium catalyzed amination-carbonylation-cyclization reaction. This sequence efficiently proceeds to build up isoquinolone in fair to good yields over a one-pot 3-bond synthesis reaction.     

Self-assembled tin-based bridged hybrid materials

Hybrid materials where layers of tin oxide alternate with layers of hydrophobic organic chains were prepared by the hydrolysis of distannylated compounds containing an organic chain alpha,omega-disubstituted by tripropynylstannyl groups. In the case of an aliphatic chain, hydrolysis under microemulsion conditions led to the organization of the corresponding hybrid. These hydrolysis conditions also induced a high surface area and a defined mesoporosity in the hybrid. When a mixed aromatic-aliphatic spacer was used, weak hydrophobic interactions between the spacers were sufficient to generate the same type of organization in the corresponding material.