Straightforward Access to Water‐Soluble Unsymmetrical Sulfoxanthene Dyes: Application to the Preparation of Far‐Red Fluorescent Dyes with Large Stokes’ Shifts

An efficient synthesis of water‐soluble unsymmetrical sulforhodamine/sulforhodol fluorophores containing a single julolidine fragment is presented. Owing to their valuable spectral properties in aqueous buffers, these dyes, especially those bearing a free aniline or phenol moiety, are valuable components of fluorogenic probes for a variety of biosensing applications. A further extension of this synthetic methodology to unusual phenols, namely 7‐N,N‐dialkylamino‐4‐hydroxy coumarins has enabled us to provide a new family water‐soluble dyes of large Stokes’ shift with far‐red spectral features.     

Comparison of two approaches for the discretization of elastodynamic contact problems

The purpose of this Note is to compare two approaches for the discretization of elastodynamic contact problems. First, we introduce an energy conserving method based on a standard midpoint scheme and a contact condition expressed in terms of velocity. The second approach consists in considering an equivalent distribution of the body mass so that the nodes on the contact boundary have no inertia. We prove that this method leads to an energy conservation for the space semi-discretized elastodynamic contact problem. Finally, some numerical results are presented in the two dimensional case. To cite this article: H.B. Khenous et al., C. R. Acad. Sci. Paris, Ser. I 342 (2006).     

Anomalous events in e+e−→μ+μ−γ. excited states and/or new interactions?

We first show that the enhancement observed by Cello can neither be explained by real or virtual μ¹ production through μ¹μγ or μ¹μZ couplings nor by μμγγ or μμγZ contact terms, when one imposes the usual constraints from $\text{g -2, e}{}^{\mathrm{+}}\text{e}{}^{\mathrm{?}}\text{→γγ, Z→}\text{ll}\text{γ}$. We then propose an explanation using an eeμμ¹ contact term which is less constrained. In addition to $\text{μ}{}^1\text{→μγ}$ this leads to a direct decay $\text{μ}{}^1\text{→μee}$. Generalized to other types of fermion pairs we have here an interesting source of multifermion anomalous events.     

Fixed point strategies for elastostatic frictional contact problems

Several fixed point strategies and Uzawa algorithms (for classical and augmented Lagrangian formulations) are presented to solve the unilateral contact problem with Coulomb friction. These methods are analysed, without introducing any regularization, and a theoretical comparison is performed. Thanks to a formalism coming from convex analysis, some new fixed point strategies are presented and compared with known methods. The analysis is first performed on continuous Tresca problem and then on the finite dimensional Coulomb problem derived from an arbitrary finite element method. Copyright © 2007 John Wiley & Sons, Ltd.     

Substructures ate + e − colliders

We review, update and propose tests of a possible substructure of leptons, quarks andW ^±,Z bosons for the next generation ofe ⁺ e ^? colliders. We successively consider the three following domains of physics: at theZ peak, out of theZ peak and in the high energy range.     

How to measure quark helicities in e+e− → hadrons

In order to reach completely the vector and axial couplings of the neutral currents to quarks we propose to measure quark helicities from the polarizations of the leading baryons of the jets. Applications are given for e⁺e^? → 2 jets where large degrees of polarization are obtained from γ-Z interference.     

Multifunctional catalysis XI : Asymmetric catalysis of the mutarotation of tetramethylglucose by optically active phosphinothioic acids.

Catalytic activities of R(+) and racemic t-butylphenylphosphinothioic acids on the mutarotation of 2,3,4,6 tetramethyl-d-glucose are studied in benzene.     

Microbiological synthesis and circular dichroism of optically active 2-deuterio-cycloalkanones

Optically active 2-deuterio-cyclopentanone and 2-deuterio-cyclohexanone have been prepared by microbiological reduction of 2-deuterio α,β-unsaturated cyclic ketones by Beauveria sulfurescens.     

A deformation rig for synchrotron microtomography studies of geomaterials under conditions down to 10 km depth in the Earth

A hard X‐ray transparent triaxial deformation apparatus, called HADES, has been developed by Sanchez Technologies and installed on the microtomography beamline ID19 at the European Radiation Synchrotron Facility (ESRF). This rig can be used for time‐lapse microtomography studies of the deformation of porous solids (rocks, ceramics, metallic foams) at conditions of confining pressure to 100 MPa, axial stress to 200 MPa, temperature to 250°C, and controlled aqueous fluid flow. It is transparent to high‐energy X‐rays above 60 keV and can be used for in situ studies of coupled processes that involve deformation and chemical reactions. The rig can be installed at synchrotron radiation sources able to deliver a high‐flux polychromatic beam in the hard X‐ray range to acquire tomographic data sets with a voxel size in the range 0.7–6.5 µm in less than two minutes.     

A novel heterotrifunctional peptide-based cross-linking reagent for facile access to bioconjugates. Applications to peptide fluorescent labelling and immobilisation

A convenient, versatile and straightforward synthesis of a novel heterotrifunctional peptide-based linker molecule is described. This generic bio-labelling reagent contains an amine-reactive N-hydroxysuccinimidyl carbamate moiety, an aldehyde/ketone-reactive aminooxy group and a thiol group with a propensity to form urea, oxime and thioether linkages respectively. The full chemical orthogonality between the free aminooxy and thiol functionalities was demonstrated through the preparation of a fluorescent reagent suitable for the selective staining of a carboxaldehyde-modified surface by means of oxime ligation. The absence of reactivity of these two functions toward the nucleophile-sensitive active carbamate was obtained by using temporary aminooxy- and thiol-protecting groups removable under mild conditions. The utility of the linker molecule to cross-link three different molecular partners has been illustrated by the preparation of fluorescent tripod-functionalised surfaces which may be useful in developing new peptide microarrays and related immunosensors.