Formal Design of Dynamic Reconfiguration Protocol for Cloud Applications

International audienceCloud applications are complex applications composed of a set of interconnected software components running on different virtual machines, hosted on remote physical servers. Deploying and reconfiguring this kind of applications are very complicated tasks especially when one or multiple virtual machines fail when achieving these tasks. Hence, there is a need for protocols that can dynamically reconfigure and manage running distributed applications. In this article, we present a novel protocol, which aims at reconfiguring cloud applications. This protocol is able to ensure communication between virtual machines and resolve dependencies by exchanging messages, (dis)connecting, and starting/stopping components in a specific order. The interaction between machines is assured via a publish-subscribe messaging system. Each machine reconfigures itself in a decentralized way. The protocol supports virtual machine failures, and the reconfiguration always terminates successfully even in the presence of a finite number of failures. Due to the high degree of parallelism inherent to these applications, the protocol was specified using the LNT value-passing process algebra and verified using the model checking tools available in the CADP toolbox. The use of formal specification languages and tools helped to detect several bugs and to improve the protocol

Removal of metronidazole from aqueous solution using activated carbon

Metronidazole antibiotic is a medication once discharged into the water after use, can react with living organisms and causing adverse effects to their lives. This kind of contaminant must be removed from wastewater and the technique adopted in this work is the liquid-solid adsorption method. The removal of metronidazole in aqueous solutions is carried out on powdered activated carbon. Different parameters such as solid/liquid ratio, temperature, pH, concentration, and contact time influencing this adsorption are examined. The Langmuir isotherm appears the most satisfactory is best suited for modeling the adsorption of metronidazole. In addition, the pH and the temperature do not seem to have any noticeable effect on the adsorption of metronidazole. The experimental results showed that metronidazole was removed at 64% for concentration of 50 mg/L for contact time of 20 min

Le dépistage des aneuploïdies en Tunisie: à quand la généralisation du calcul de risque intégré au premier trimestre ?

En Tunisie, nous ne disposons pas de plan national de dépistage des aneuploïdies. Nous nous proposons de comparer pour une même population deux méthodes de dépistage des aneuploïdies, et de discuter de l'importance de la qualité des mesures de la clarté nucale lors de l'échographie du premier trimestre. Il s'agit d'une étude prospective réalisée sur une période de 18 mois. Nous avons comparé les résultats du calcul de risque réalisé selon deux méthodes. La première tenant compte uniquement de l'âge maternel et des marqueurs sériques, et la deuxième intégrant en plus la clarté nucale. 19% des 221 parturientes étaient âgées de plus de 38 ans. Le test de dépistage selon la 1ère méthode était sensible pour le seul cas d'aneuploïdie rencontré. La puissance de ce test était de 60%. Le dosage des marqueurs sériques du deuxième trimestre a permis le dépistage des défauts de fermeture du tube neural avec une valeur statistiquement significative en termes de spécificité (98,6%) et de valeur prédictive négative (100%). La médiane des mesures de CN était de 0,75 MoM pour l'âge gestationnel. Uniquement 17,6% des mesures étaient situées dans l'intervalle [0,9 -1,1] MoM. Nous n'avons pas objectivé de différence significative entre les deux méthodes dépistage en matière de puissance. Cependant, en termes de faux positifs le test combiné s'est avéré plus intéressant, son utilisation aurait pu nous éviter 18 prélèvements invasifs. L'avenir immédiat en Tunisie doit se diriger vers un dépistage combiné au premier trimestre. Cette stratégie ne peut se faire qu'après instauration d'un contrôle qualité des mesures à la fois biologiques et échographiques.Pan African Medical Journal 2016; 2

Asynchronous synthesis techniques for coordinating autonomic managers in the cloud

International audienceCloud computing allows the delivery of on-demand computing resources over the internet on a pay-for-use basis. From a technical point of view, cloud applications usually consist of several software components deployed on remote virtual machines. Managing such applications is a challenging problem because manual administration is no longer realistic for these complex distributed systems. Thus, autonomic computing is a promising solution for monitoring and updating these applications automatically. This is achieved through the automation of administration functions and the use of control loops called autonomic managers. An autonomic manager observes the environment , detects changes, and reconfigures dynamically the application. Multiple autonomic managers can be deployed in the same system and must make consistent decisions. Using them without coordination may lead to inconsistencies and error-prone situations. In this article, we first present a simple language for expressing coordination constraints given a set of auto-nomic managers. Second, given a coordination expression written with that language, we propose new synthesis techniques for automatically generating an asynchronous controller. These synthesis techniques work in two steps by successively generating a model of the controller and a Java object corresponding to this model. This Java code is finally used for deploying the generated controller. As far as evaluation is concerned, we validated our approach by using it for coordinating real-world cloud applications

Metabolism of triflumuron in the human liver: Contribution of cytochrome P450 isoforms and esterases.

Abstract Triflumuron (TFM) is a benzoylurea insecticide commonly used in Tunisian agriculture and around the world to control crop pests and flies as a promising alternative to conventional insecticides for its arthropod specificity and low toxicity. From the evidence available in animal models, it can be expected that the metabolism of TFM is catalyzed by cytochrome P450 (CYP) and esterases. However, no data are available on human metabolism of TFM with regards to phase I metabolism and CYP isoform specificity. Hence, this manuscript describes experimental investigations to underpin in vitro phase I TFM metabolism in human samples for the first time. TFM biotransformation by recombinant human CYPs was characterized, then human liver microsomes (HLM) and chemical specific inhibitors have been used to identify the relative contribution of CYPs and esterases. Our results showed that all CYP isoforms were able to metabolize TFM with different affinity and efficiency. The relative contribution based both on the kinetic parameters and the CYP hepatic content was 3A4 > >2C9 > 2C8 > 2A6 > 1A2 > 2B6 > 2D6 > 2C19 > 2C18 > 1A1 at low TFM concentration, whilst at high TFM concentration it was 1A2 > >2C9 = 3A4 = 2A6 > 2C19 > 2B6 = 2C8 > 2D6 > 1A1 > 2C18. Experiments with HLMs confirmed the involvement of the most relevant CYPs in the presence of specific chemical inhibitors with a catalytic efficiency (Cliapp) lower by an order of magnitude compared with recombinant enzymes. Esterases were also relevant to the overall TFM kinetics and metabolism, with catalytic efficiency higher than that of CYPs. It is foreseen that such isoform-specific information in humans will further support in silico models for the refinement of the human risk assessment of single pesticides or mixtures

Sarcoidosis with heart involvement: a rare association of terrible prognosis, a report of two cases

Sarcoidosis is a multisystemic disorder of unknown etiology which is characterized by the formation of  non-caseating granulomas in involved tissues. Cardiac involvement is one of the least common manifestations and it can occur at any point of time during the course of sarcoidosis. Here we present the case of 2 patients with known sarcoidosis who develop cardiac abnormalities in the absence of known primary cardiac cause. In our report, we would like to draw attention to the importance of considering heart involvement in any case with systemic sarcoidosis especially in young age.Key words: Cardiac sarcoidosis, Sarcoidosis, Ventricular arrhythmia

The implication of ROS production on triflumuron-induced oxidative stress and genotoxicity in human colon carcinoma (HCT-116) cells

The aim of this study is to evaluate the cytotoxic and the genotoxic effects of triflumuron (TFM) on human colon carcinoma cells (HCT-116). Indeed, TFM is used to protect vegetables, fruits, and domestic animals against a large spectrum of parasites causing animal and human disorders. However, studies revealing its toxicity and its mode of action in mammalian systems remain very limited. We monitored our work with the cytotoxicity assay starting with the cell viability test, the ROS generation, the malondialdehyde (MDA) production, the DNA fragmentation, and the measurement of some antioxidant enzymes activities such as catalase, superoxide dismutase, and the glutathione S-transferase. Also, we measured the mitochondrial transmembrane potential. We showed that TFM induced a dose-dependent cell death. This decrease in cell viability was accompanied by a significant reduction in the mitochondrial membrane potential. We also have shown that TFM induced oxidative stress as revealed by the generation of reactive oxygen species, the increase of the MDA levels, and the activation of the antioxidant enzymes. Moreover, our results indicated that TFM induced DNA damage in HCT-116 cells as monitored by the comet assay. We demonstrate, for the first time, the cytotoxic and the genotoxic potentials of TFM on human cultured cells

Obésité, activité physique et temps de sédentarité chez des adolescents scolarisés, âgés de 15 à 18 ans de la ville de Sfax (Tunisie)

Introduction: Le but de notre étude était d'évaluer la prévalence du surpoids et de l'obésité chez des adolescents scolarisés dans la ville de Sfax mais aussi, d'étudier son association avec le temps de sédentarité et l'activité physique (AP). Méthodes: La population étudiée était composée de 1695 adolescents âgés de 15-18 ans. Tous les participants avait rempli un questionnaire porté sur leurs activités physiques et temps de sédentarité, donné lors d'un entretien direct. Le niveau d'AP était évalué avec l'International Physical Activity Questionnaire (IPAQ) version courte. Résultats: Notre étude comportait 43,7% de garçons et 56,3% de filles. L'âge moyen était de 16,78 ± 1, 1 an. Dans notre échantillon, 23,4% des adolescents étaient en surpoids ou obèses. Le score de l'IPAQ nous a montré que le niveau d'AP de nos participants était faible dans 6,4%, modéré dans 65,4% et élevé dans 28,2% des cas. Nos résultats avaient démontré que l'augmentation du temps de sédentarité (plus de 2 h / jour) est associée à une augmentation significative de l'indice de masse corporelle (IMC) et du tour de taille (TT) (P <0,001). Alors qu'un niveau d'AP élevé et/ou la participation aux séances d'AP structurées dans le cadre scolaire et hors scolaire est accompagnée par une diminution significative de l'IMC et du TT (P <0,001). Conclusion: Nos résultats apportent une preuve supplémentaire sur la nécessité de promouvoir la vie active chez les jeunes Tunisiens.Pan African Medical Journal. 2015; 2

Asynchronous Coordination of Stateful Autonomic Managers in the Cloud

International audienceCloud computing is now an omnipresent paradigm in modern programming. Cloud applications usually consist of several software components deployed on remote virtual machines. Managing such applications is a challenging problem because manual administration is no longer realistic for these complex distributed systems. Thus, auto-nomic computing is a promising solution for monitoring and updating these applications automatically. This is achieved through the automation of administration functions and the use of control loops called au-tonomic managers. An autonomic manager observes the environment, detects changes, and reconfigures dynamically the application. Multiple autonomic managers can be deployed in the same system and must make consistent decisions. Using them without coordination may lead to inconsistencies and error-prone situations. In this paper, we present our approach for coordinating stateful autonomic managers, which relies on a simple coordination language, new techniques for asynchronous controller synthesis and Java code generation. We used our approach for coordinating real-world cloud applications

Improved functionalization of oleic acid-coated iron oxide nanoparticles for biomedical applications

Superparamagnetic iron oxide nanoparticles can providemultiple benefits for biomedical applications in aqueous environments such asmagnetic separation or magnetic resonance imaging. To increase the colloidal stability and allow subsequent reactions, the introduction of hydrophilic functional groups onto the particles’ surface is essential. During this process, the original coating is exchanged by preferably covalently bonded ligands such as trialkoxysilanes. The duration of the silane exchange reaction, which commonly takes more than 24 h, is an important drawback for this approach. In this paper, we present a novel method, which introduces ultrasonication as an energy source to dramatically accelerate this process, resulting in high-quality waterdispersible nanoparticles around 10 nmin size. To prove the generic character, different functional groups were introduced on the surface including polyethylene glycol chains, carboxylic acid, amine, and thiol groups. Their colloidal stability in various aqueous buffer solutions as well as human plasma and serum was investigated to allow implementation in biomedical and sensing applications.status: publishe