Surface granularity as a discriminating feature of illicit tablets.

In this paper we propose an innovative methodology for automated profiling of illicit tablets by their surface granularity; a feature previously unexamined for this purpose. We make use of the tiny inconsistencies at the tablet surface, referred to as speckles, to generate a quantitative granularity profile of tablets. Euclidian distance is used as a measurement of (dis)similarity between granularity profiles. The frequency of observed distances is then modelled by kernel density estimation in order to generalize the observations and to calculate likelihood ratios (LRs). The resulting LRs are used to evaluate the potential of granularity profiles to differentiate between same-batch and different-batches tablets. Furthermore, we use the LRs as a similarity metric to refine database queries. We are able to derive reliable LRs within a scope that represent the true evidential value of the granularity feature. These metrics are used to refine candidate hit-lists form a database containing physical features of illicit tablets. We observe improved or identical ranking of candidate tablets in 87.5% of cases when granularity is considered.

Changes in silicon elastomeric surface properties under stretching induced by three surface treatments.

Poly(dimethylsiloxane) (PDMS) substrates are used in many applications where the substrates need to be elongated and various treatments are used to regulate their surface properties. In this article, we compare the effect of three of such treatments, namely, UV irradiation, water plasma, and plasma polymerization, both from a molecular and from a macroscopic point of view. We focus our attention in particular on the behavior of the treated surfaces under mechanical stretching. UV irradiation induces the substitution of methyl groups by hydroxyl and acid groups, water plasma leads to a silicate-like layer, and plasma polymerization causes the formation of an organic thin film with a major content of anhydride and acid groups. Stretching induces cracks on the surface both for silicate-like layers and for plasma polymer thin coatings. This is not the case for the UV irradiated PDMS substrates. We then analyzed the chemical composition of these cracks. In the case of water plasma, the cracks reveal native PDMS. In the case of plasma polymerization, the cracks reveal modified PDMS. The contact angles of plasma polymer and UV treated surfaces vary only very slightly under stretching, whereas large variations are observed for water plasma treatments. The small variation in the contact angle values observed on the plasma polymer thin film under stretching even when cracks appear on the surface are explained by the specific chemistry of the PDMS in the cracks. We find that it is very different from native PDMS and that its structure is somewhere between Si(O2) and Si(O3). This is, to our knowledge, the first study where different surface treatments of PDMS are compared for films under stretching.

[Surgical prevention of retinal detachment]. / Prévention chirurgicale du décollement de la rétine.

Prophylaxis of rhegmatogenous retinal detachment consists of measures both non surgical and/or surgical that are effective in preventing some risk-factors that are part of the disease. The procedure must avoid any types of danger. This paper describes a new reliable surgical procedure of circular buckling used for prophylaxis on predisposed fellow-eye of giant retinal tear.

[Prevention of retinal detachment. Whom to treat?]. / Prévention du décollement de la rétine. Qui traiter?

Natural history of retinal detachment (RD) studies on clinical exam of 200 patients revealed that RD, is the consequence of multiple risk factors preparing to PVD. This phenomenon depends therefore from peculiar background, patient's age, and opportunistic traumatism. The best prophylaxis would be represented by a mean of inducing PVD without retinal damage. Since no possibilities are present right now, retinopexy or surgical mechanical action are used as prophylactic methods. Results are discussed in this paper based on long-term-follow-up of 300 patients.

[A universal laser for intraocular treatment]. / Laser universel pour traitement intraoculaire.

The creation of a single apparatus incorporating the different lasers applicable to intraocular pathology derives from the idea of possessing the means, with one device, of objectively comparing the effects and parameters of various lasers in order to pursue a more precise line of treatment. This has led to our fabrication of the universal intraocular laser. The word universal means the ability of the machine to act on each kind of intraocular tissues with all of the various infrared or other-colored radiations, as well as with different modalities. The unit is transportable. It only requires a source of electric power (110 or 220 V) and includes an independent cooling system. The Nd: YAG laser has selectable operating parameters: pulsed or continuous excitation, Q-switched or mode-locked mode, mirror or fiber optic transmission. It is used also as the basic system of the coloured module. The colour module can provide the three clinically useful radiations: green, red, yellow. The green (532 nm) is obtained by transmission of the I.R. beam brought a birefringent crystal (KTP). Red (650 nm) and yellow (575 nm) come from two incorporated dye lasers excited by the green radiation.

[Modernization of ophthalmoscopic techniques]. / Modernisation des techniques d'ophtalmoscopie.

The great principles of ophthalmoscopy have been known for many decades. This paper intends show the new possibilities allowed by modern technology, especially in two fields. First of all, it is possible, even in keeping basic principles, to improve previous machines with, for example, better magnification, new ophthalmoscopic lens, or to create new materials as telescopes for clinical practice or intra-ocular surgery, wide angle or high magnification fundus cameras for posterior pole examination. Secondary, by revolutionary principles, it is possible to introduce laser in the ophthalmoscopic field and to imagine new ophthalmoscopes: SLO i.e. Scanning Laser Ophthalmoscope or SLM i.e. Scanning Laser Microscope, which opens a window on the future.

[Stabilization of the laser on the target. Scanning photocoagulator: the SLC (scanning laser coagulator)]. / Stabilisation du laser sur la cible. Photocoagulateur à balayage: S.L.C.

When lasers are used to cause burns on the retina they necessitate systems of great precision especially in the posterior pole. Different possibilities are now offered. The best one is based on the intensification of the same laser beam used for the observation in the Scanning Laser Ophthalmoscope: S.L.O. when it is at a point selected from the angiogram, converting this machine into a Scanning Laser Coagulator: S.L.C.