State-of-the-art treatment of hypertension: established and new drugs

The treatment of essential hypertension is based essentially on the prescription of four major classes of antihypertensive drugs, i.e. blockers of the renin-angiotensin system, calcium channel blockers, diuretics and beta-blockers. In recent years, very few new drug therapies of hypertension have become available. Therefore, it is crucial for physicians to optimize their antihypertensive therapies with the drugs available on the market. In each of the classes of antihypertensive drugs, questions have recently been raised: are angiotensin-converting enzyme (ACE) inhibitors superior to angiotensin II receptor blockers (ARB)? Is it possible to reduce the incidence of peripheral oedema with calcium antagonists? Is hydrochlorothiazide really the good diuretic to use in combination therapies? The purpose of this review is to discuss these various questions in the light of the most recent clinical studies and meta-analyses. These latter suggest that ACE inhibitors and ARB are equivalent except for a better tolerability profile of ARB. Third generation calcium channel blockers enable to reduce the incidence of peripheral oedema and chlorthalidone is certainly more effective than hydrochlorothiazide in preventing cardiovascular events in hypertension. At last, studies suggest that drug adherence and long-term persistence under therapy is one of the major issues in the actual management of essential hypertensio

A Cookbook of Self-Supervised Learning

Self-supervised learning, dubbed the dark matter of intelligence, is a promising path to advance machine learning. Yet, much like cooking, training SSL methods is a delicate art with a high barrier to entry. While many components are familiar, successfully training a SSL method involves a dizzying set of choices from the pretext tasks to training hyper-parameters. Our goal is to lower the barrier to entry into SSL research by laying the foundations and latest SSL recipes in the style of a cookbook. We hope to empower the curious researcher to navigate the terrain of methods, understand the role of the various knobs, and gain the know-how required to explore how delicious SSL can be

Etude expérimentale et numérique de la dispersion explosive et de la combustion de particules métalliques

The explosive dispersion of particles and their inflammation in air along with the blast wave effects were investigated experimentally and numerically. The experimental configuration consisted in studying the free-field explosion of spherical charges made of a central booster of solid explosive surrounded by a loose-packed density shell of inert (glass spheres) or reactive (atomized and flaked aluminium) particles. The high speed cinematography of the explosions coupled with image processing by a "Background Oriented Schlieren" method, and the pressure records by piezoelectric gauges permit to plot the x-t diagrams of the explosions. A technique has been developed to capture samples of dispersed particles and to make their post-analysis. The experimental results are confronted with numerical simulations performed with LCD's reactive multiphase flows code EFAE. The boundary of the dispersed cloud is not uniform but has a spiky shape with dendrites due to the formation of particle agglomerates of several millimetres. After 1m of propagation, some of those agglomerates overcome the leading shock front due to a ballistic effect. Glass particles are disintegrated by the shock. They have a mitigating effect, making the shock propagation slower and decreasing its amplitude. The effect of aluminium particles depends on their size: with the finer ones, after an initial slowdown phase, a re-acceleration of the leading shock and an increase of the pressure impulse are observed. With coarser particles, the shock is weakened but particle combustion raises the pressure level behind the shock front and slightly increases its impulse. An analysis of the collected agglomerates reveals that, in all cases, the combustion of aluminium particles is incomplete. Numerical simulations are in reasonable agreement with experimental results in the farfield domain.La dispersion de particules solides par explosif et leur inflammation dans l'air, ainsi que des effets de souffle générés sur le milieu connexe ont été étudiés par voie expérimentale et numérique. La configuration retenue est l'explosion en champ libre de charges sphériques, constituées d'un noyau central d'explosif solide (booster), entouré de particules inertes (billes de verre) ou réactives (particules d'aluminium). Les diagrammes de marche sont tracés à partir des résultats fournis par des capteurs de pression piezo-électriques et des images obtenues par cinématographie rapide et traitées numériquement par méthode de "Background Oriented Schlieren" (BOS). Des échantillons de particules capturés dans le nuage fournissent des informations sur leur état après l'explosion. Les résultats expérimentaux sont confrontés aux simulations numériques effectuées à l'aide du code de calcul d'écoulements réactifs multiphasiques EFAE du LCD. La frontière du nuage formé présente un aspect caractéristique en forme de dendrites, due à la formation d'agglomérats de particules de quelques millimètres. Après 1m de propagation, une partie de ces agglomérats dépasse le choc incident par effet balistique. Les particules de verre sont brisées par le choc. Elles ralentissent l'onde de souffle et diminuent son amplitude. L'effet des particules d'aluminium dépend de leur taille : avec les plus fines, on observe, après une phase initiale de ralentissement de l'onde de souffle, la ré-accélération de celleci et une augmentation de l'impulsion de pression. Avec les plus grosses particules, le choc s'atténue, mais leur combustion se traduit par une augmentation de la pression dans l'écoulement en arrière du front et un faible accroissement de l'impulsion. Les agglomérats recueillis indiquent que, dans tous les cas, la combustion de l'aluminium est incomplète. Les simulations numériques sont en accord raisonnable avec les résultats expérimentaux dans le champ lointain

Ingénierie des systèmes de sécurité

Explosion protection is the object of various national and international documents, that are focused on the functions, the intended uses or the dimensioning rules for specific systems. However, despite a few application examples are described in the usual guidelines, they are limited to the description of a protection that can be added on a single piece of equipment while it is not the case in industrial processes. Furthermore, in an ATEX explosion there is a strong coupling between the explosion and its environment. Because of this the guidelines recommendations cannot be transposed on an industrial site without due consideration. In this paper, a way to take into account the real explosion conditions is given allowing a choice and dimensioning of a set of safety systems. An example is shown based on a real installation. The functional properties of the safety system are extracted from the certification tests whereas the explosion characteristics are extracted both from the standard combustion properties of the dust and from the latest knowledge about flame propagation.La protection contre les explosions fait l’objet de plusieurs documents, nationaux et internationaux, qui décrivent la fonction, les applications et les règles de dimensionnement de systèmes de protection spécifiques. Toutefois, bien que des exemples d’application figurent dans les guides de bonne pratique, ils sont limités à la description de solutions de protection pour des équipements considérés isolément, ce qui n’est pas représentatif des situations industrielles réelles. En pratique, le dimensionnement correct d’un système de protection doit tenir compte des fortes interactions qui existent entre une explosion et l’environnement dans lequel elle se développe. Dans cet article, une manière de tenir compte des conditions réelles de développement des explosions est présentée, qui permet de sélectionner et dimensionner des systèmes de protection adaptés à l’application industrielle. Un exemple est donné sur la base d’une installation réelle. Les paramètres fonctionnels des systèmes proposés sont issus d’essais d’explosion, tandis que les caractéristiques des explosions sont calculées à partir des propriétés de combustion des poussières et des connaissances les plus récentes sur la propagation des flammes

Dust explosion development in a vessel-duct arrangement

In many practical situations, a flame may appear inside a vessel and start to propagate inside the connected pipes. It may be a very hazardous situation and several mitigation means were developed to stop the subsequent explosion escalation (chemical barriers, gate valves, flap valves, diverters). There is a need to better understand the development of the explosion in such a situation. Unpublished data are presented in the present paper using mainly the ISO 1 m3 vessel connected to ducts with an internal diameter varying between 100 mm and 440 mm (length between 0 and 10 m). Four very different dusts were used. In all situations a strong link is found between the vessel overpressure and the flame velocity along the duct. Moreover, all along the period during which the flame rushes down the pipe, the discharge of the vessel is severely impeded and this phenomenon is believed to explain the very significant incidence of even a relatively short portion of duct on the explosion overpressure inside the duct as claimed into the vent dimensioning standards

Performance of a universal adhesive on etched and non-etched surfaces: Do the results match the expectations?

International audienceA universal adhesive was applied to human dentin in both the etched and rinsed state and the normal non etched state, to compare the resulting properties and detect any significant differences. The study focused on observations of the hybrid layer by scanning electron microscopy and on fluid permeation measurements as a function of time. Spectroscopic characterizations included infrared and differential calorimetric curves of the samples. The results obtained show non-statistically significant fluid permeability between the two sample types. Both the etched and rinsed samples and the non-etched ones showed similar homogeneous hybrid layers that reduced the fluid flow, and corresponded to well spread polymer coatings. The infrared results illustrated the spectra obtained on going from the outside adhesive layer to the inside portion of the dentin-polymer interface and did not reveal any intermediate zone resembling demineralized collagen that would be water saturated and not infiltrated with adhesive. The Differential Scanning Calorimetry (DSC) curves corresponded to the curves obtained with ethanol wet bonding in that free water (melting at 0 degrees C) was removed by the universal adhesive, and that no collagen melting was observed for the non-etched samples. The Diffusion-Ordered Spectroscopy Nuclear Magnetic Resonance (DOSY NMR) spectrum of the virgin adhesive showed the presence of water and ethanol solvents and indicated that several monomer or prepolymer molecules were present with multiple acrylic functional groups with diffusion coefficients related to molecular weights. Overall, the results show that universal adhesive can be used in the milder self-etch mode and that more aggressive etch and rinse procedure can be reserved for the occasions with sclerotic dentin or enamel regions more difficult to treat. (C) 2016 Published by Elsevier B.V

On the Usefulness of Phenomenological Approach to Model Explosions in Complex Industrial Systems

Explosion protection is the object of various national and international documents, which are focused on the functions, the intended uses or the dimensioning rules for specific systems. However, despite a few application examples are described in the usual guidelines, they are limited to the description of a protection that can be added on a single piece of equipment while it is not the case in industrial processes. Furthermore, in an ATEX explosion there is a strong coupling between the explosion and its environment. Because of this the guidelines recommendations cannot be transposed on an industrial site without due consideration. In this paper, a way to consider the real explosion conditions is given allowing a choice and dimensioning of a set of safety systems. An example is shown based on the example of a model of a real installation. The functional properties of the safety system are extracted from the certification tests whereas the explosion characteristics are extracted both from the standard combustion properties of the dust and from the latest knowledge about flame propagation. A specific focus is made on two fundamental aspects: on the one hand, the critical importance to understand how the flame propagates in a given complex system. On the other hand, the behaviour of the protection systems that can be used with caution as they quite systematically influence the explosion driven flow

Flameless venting : achievements and difficulties

Flameless venting is a sort of dual mitigation technique allowing, in principle, to vent a process vessel inside a building where people are working without transmitting a flame outside the protected vessel. Existing devices are an assembly of a vent panel and a metal filter so that the exploding cloud is forced to go through the filter. Within the frame of ATEX Directive, those systems need to be certified. To do so a standard (NF EN 16009) has been issued describing which criteria need to be verified / measured. Among them, the “efficiency” factor as defined earlier for standard vents. This implies that flameless venting systems are basically considered as vents. But is it really so? The practical experience of INERIS in testing such systems is presented in this paper. Schematically, with a flameless vent the pressure is discharged but not the flame so that combustion is proceeding to a much longer extent inside the vessel than with a classical vent. Therefore the physics of the explosion is different. This question is discussed on the basis of experimental results and some implications on the practical use and certification process are drawn