Cyclization of 2- and 3-indolylthiobenzoic,phenylacetic and nicotinic acids and esters to novel indole-containing tetracyclic ring systems

A series of 2- and 3-indolylthio benzoic, phenylacetic and nicotinic acids or esters were cyclized under dehydrative conditions affording several tetracyclic indole-containing ketones, several of which constitute the first reported examples of novel ring systems, such as the [1]benzothiepino[2,3-b] and [3,2-b]indole and the pyrido[3′2′:5,6] and [3′4′:5,6]thiopyrano[2,3-b] and [3,2-b]indole as well as the [3′2′:5,6] and [3′4′:5,6][1,3]thiazino[3,2-a]indole ring systems.     

Über erzwungene Schwingungen bei endlichen Amplituden

Ohne Zusammenfassung     

Evidence for proteolytic cleavage of brevican by the ADAMTSs in the dentate gyrus after excitotoxic lesion of the mouse entorhinal cortex

Background  

Brevican is a member of the lectican family of aggregating extracellular matrix (ECM) proteoglycans that bear chondroitin sulfate (CS) chains. It is highly expressed in the central nervous system (CNS) and is thought to stabilize synapses and inhibit neural plasticity and as such, neuritic or synaptic remodeling would be less likely to occur in regions with intact and abundant, lectican-containing, ECM complexes. Neural plasticity may occur more readily when these ECM complexes are broken down by endogenous proteases, the ADAMTSs (a disintegrin and metalloproteinase with thrombospondin motifs), that selectively cleave the lecticans. The purpose of these experiments was to determine whether the production of brevican or the ADAMTS-cleaved fragments of brevican were altered after deafferentation and reinnervation of the dentate gyrus via entorhinal cortex lesion (ECL).     

An isoperimetric inequality for the principal eigenvalue of the Laplacian with drift

We generalize the classical Rayleigh–Faber–Krahn inequality to the case of the Dirichlet Laplacian with a drift. We also solve some optimization problems for the principal eigenvalue of the operator $?\mathrm{\Delta }+v?\mathrm{?}$ in a fixed domain with a control of the drift v in $L^{\infty }$. To cite this article: F. Hamel et al., C. R. Acad. Sci. Paris, Ser. I 340 (2005).     

Spectroscopic evidence for pi-pi interaction between poly(diallyl dimethylammonium) chloride and multiwalled carbon nanotubes

The interaction between multiwalled carbon nanotubes (MWCNTs) and aqueous poly(diallyl dimethylammonium) chloride (PDDA) was studied by X-ray photoelectron (XPS) and photoacoustic Fourier transform infrared (PA-FTIR) spectroscopies. We have found that the mild sonication of MWCNTs in aqueous PDDA results in a significant improvement of CNT dispersibility and greatly enhances their adhesion to Au and Si substrates. The MWCNT-PDDA interaction is due to the presence of an unsaturated contaminant in the PDDA chain, as confirmed by both XPS and PA-FTIR, which enters into a pi-pi interaction with the CNTs. Electrostatic group repulsions of the coated CNTs then provide the dispersibility and adhesion.     

Pressure-induced hydrogen bonding: structure of D2S phase I'

The full structure of the high-pressure cubic phase I' of hydrogen sulfide has been solved using neutron diffraction data. The molecules are partially rotationally disordered about the <111> axes, as in phase II at ambient pressure but with markedly greater nonuniformity of the toroidal D distribution. The changes in structure at the II-->I' transition signal the onset of significant pressure-induced hydrogen bonding.     

Charged particle productions at 90° in the center of mass in very high energy proton-proton collisions

The transverse momentum distribution at 90° of pions, protons and antiprotons have been measured at the CERN intersecting storage rings for C.M. energies between 23.2 and 52.7 GeV. In this energy range, the pion and proton distributions are almost energy independent. The antiproton production rises by a factor of two between 23.2 and 52.7 GeV.     

Duree de vie et facteur de lande du niveau (5s5p2)4P12 de L'ion etain Sn+

Oriented Sn⁺ ions in the (5s5p²)⁴P_{$\text{1}\text{2}$} level are produced by Penning collisions between Sn atoms in the ground state and optically oriented He (2³S₁) metastable atoms. If r.f. transitions are induced in the 2³S₁ He level, the circularly polarized light emitted by the ions in a direction perpendicular to the magnetic field is modulated at the r.f. frequency; the variation of the degree of modulation with the r.f. frequency allows a determination of the lifetime τ' of the ion level. The lifetime and the Landé g-factor of the Sn⁺ (⁴P_{$\text{1}\text{2}$}) level are also measured by direct magnetic resonance. The line shape is also computed when the resonances of the He atom and of the Sn⁺ ion overlap; the experimental signals are in good agreement with this computation.     

Constructive and destructive interference in acoustic emission during fatigue crack propagation

Fatigue crack propagation monitoring with acoustic emission reveals the presence of maxima and minima in the curve of the count rate as a function of the stress intensity factor. This is explained in terms of constructive and destructive interference due to specimen geometry. A theoretical model is developed and experimental proof of the validity of the model is presented.