Études et portraits politiques

L'histoire du consulat et de l'empire, par M. Thiers.--Daunou.--Carnot.--Armand Carrel.--M. Guizot.--M. Proudhon.--Le rétablissement de la Pologne.--Paris en Amérique, par M. E. Laboulaye.--Du régime parlementaire sous Louis-Philippe.--Un dernier mot sur Carnot.Mode of access: Internet

Technique de la "boucle vasculaire saphene" dans le traitement des pertes de substance du membre inferieur. A propos de 5 cas

Five patients with high energy trauma of the lower limb with tissue defect located in the knee or the proximal third of the leg underwent reconstruction with a free latissimus dorsi flap. This flap was connected to a vascular saphenous loop which initially creates an arterioveous shunt between proximal femoral vessels. This was performed in a single operation with two teams of surgeons. This technique was chosen because a healthy recipient pedicle was not available in the vicinity of the defect. Application of vein grafts is not the usual procedure but there are situations in which it becomes necessary. Our aim in this paper is to discuss these situations, to describe the technique used in our Hospital and to analyze the advantages and disadvantages of a one or two-stage operation

Low frequency noises and DLTS studies in HgCdTe MWIR photodiodes

International audienceBoth low frequency noises and electrically active defects have been investigated for two technological variants, i.e. optimized and non-optimized, of the HgCdTe p on n technology applied to the mid wave infrared (MWIR) blue band with a cutoff wavelength of 4.2 µm. This has been achieved using electro-optical characterizations and the deep level transient spectroscopy (DLTS) technique. The results show that the impact of extra 1/f and random telegraph signal (RTS) noises has been reduced with the optimization of the technology. Furthermore, a broadened DLTS peak, probably related to dislocations in the material, has been found for both variants, the relative amplitude of which is reduced in the optimized case. The potential correlation between low frequency noises and this broadened peak is discussed

Synthetic, structural, and spectroscopic studies of sterically crowded tin-chalcogen acenaphthenes

The work in this project was supported by the Engineering and Physical Sciences Research Council (EPSRC) and EaStCHEM.A series of sterically encumbered peri-substituted acenaphthenes have been prepared containing chalcogen and tin moieties at the close 5,6-positions (Acenap[SnPh3][ER], Acenap = acenaphthene-5,6-diyl, ER = SPh (1), SePh (2), TePh (3), SEt (4); Acenap[SnPh2Cl][EPh], E = S (5), Se (6); Acenap[SnBu2Cl][ER], ER = SPh(7), SePh (8), SEt (9)). Two geminally bis(peri-substituted) derivatives ({Acenap[SPh2]}2SnX2, X = Cl (10), Ph (11)) have also been prepared, along with the bromo–sulfur derivative Acenap(Br)(SEt) (15). All 11 chalcogen–tin compounds align a Sn–CPh/Sn–Cl bond along the mean acenaphthene plane and position a chalcogen lone pair in close proximity to the electropositive tin center, promoting the formation of a weakly attractive intramolecular donor–acceptor E···Sn–CPh/E···Sn–Cl 3c-4e type interaction. The extent of E→Sn bonding was investigated by X-ray crystallography and solution-state NMR and was found to be more prevalent in triorganotin chlorides 5–9 in comparison with triphenyltin derivatives 1–4. The increased Lewis acidity of the tin center resulting from coordination of a highly electronegative chlorine atom was found to greatly enhance the lp(E)−σ*(Sn–Y) donor–acceptor 3c-4e type interaction, with substantially shorter E–Sn peri distances observed in the solid state for triorganotin chlorides 5–9 (∼75% ∑rvdW) and significant 1J(119Sn,77Se) spin–spin coupling constants (SSCCs) observed for 6 (163 Hz) and 8 (143 Hz) in comparison to that for the triphenyltin derivative 2 (68 Hz). Similar observations were observed for geminally bis(peri-substituted) derivatives 10 and 11.PostprintPeer reviewe