Regular arrays of Pd and PdAu clusters on ultrathin alumina films for reactivity studies.

Hexagonal arrays of Pd and PdAu clusters are produced by condensation of metal vapors under UHV on a nanostructured alumina ultrathin film at 320 K. The alumina presents a hexagonal network of point defects that are nucleation centers for Pd. The growth of the Pd clusters is uniform leading to a very narrow size distribution in the range of size of few atoms to about 400 atoms.

Long-range ordered nanodomains of grafted electroactive molecules.

We demonstrate the capability to build zero and one-dimensional electroactive molecular nanostructures ordered over a macroscopic scale and stable under ambient conditions. To realize these arrays, we use the selective grafting of functionalized thiols (juglon and terthiophene based) on a self-organized metallic template. The nanoscale patterning of the molecular conductance is demonstrated and analyzed by scanning tunneling spectroscopy.

Transition from molecule to solid state: reactivity of supported metal clusters.

The evolution of the adsorption energy of carbon monoxide (CO) molecules on palladium (Pd) clusters as function of Pd particle size from the molecular regime (less than ~100 atoms per particle) to the bulk regime has been revealed. This adsorption energy is retrieved from the residence time of CO molecules on the Pd clusters, measured by a pulsed molecular beam technique, versus temperature. Unprecedented accuracy on the determination of the particle size has been achieved here by using a regular array of metal clusters exhibiting a size dispersion down to the ultimate limit of a Poisson distribution.

Preparation of regular arrays of bimetallic clusters with independent control of size and chemical composition.

Regular arrays of bimetallic clusters have been prepared by atomic deposition, under UHV, on a nanostructured ultrathin alumina film. The alumina films are obtained by oxidation at 1000 K of a Ni3Al (111) surface. They present two regular hexagonal superstructures with lattice parameters of 2.

[Indications, technics and results of cataract surgery on an eye effected with healed or present retinal detachment or predisposed to detachment].

This communication is a survey of 53 cataract operations followed up during a period of 1-6 years, with an average of 4 years, and performed on patients who had a high risk of subsequent retinal detachment because of a preceding detachment on the fellow eye or on the cataractous eye, because of peripheral retinal degenerations, or a history of hereditary retinal detachment. Most of the operations were performed under general anesthesia and ocular hypotony. In all the cases, a limbal-based conjonctival flap with a double line of sutures (scleral and conjonctival), an iridectomy in segment, a zonulolysis and a cryoextraction, were done.

[Reabsorbable polyglactin sutures. Clinical and experimental studies (author's transl)].

Authors report polyglactin suture's experience in anterior segment surgery. Absorbable sutures have good tolerance, their disappearing delay is slow enough to allow good scar. Experiment shows that absorption is secondary to hydrolysis without inflammatory or necrotic reaction.

[Puncture in retinal detachment surgery].

This survey has been carried out over 186 operations for retinal detachment during which a voluntary or accidental drainage took place in 2/3 of the cases. Its frequency is studied according to the type of the detachment, its age, the duration of the preperatory rest, the number of operations and the surgical technique. The postsurgical evolution of detachments with drainage shows that the vitreous is more frequently clouded, later cleared up, and that there are more choroidal detachments and more retinal hemorrhages.