5,012 research outputs found

    Atrial fibrillation and its determinants after radiofrequency ablation of chronic common atrial flutter

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    Aim. Atrial fibrillation (AFib) is a major clinical issue and its occurrence is the main problem after catheter ablation of atrial flutter. The long-term occurrence of AFib after common atrial flutter ablation is still matter of debate as it may influence the therapeutic approach. So, the aim of our study was to analyze the determinants and the time course of AFib after radiofrequency catheter ablation of chronic common atrial flutter. Methods and Results. 89 consecutive patients (67.5 ± 12.0 yrs) underwent RF ablation of chronic common atrial flutter. 38.2 % had previous history of paroxysmal AFib. 51% had no underlying structural heart disease. Over a mean follow-up of 38 ± 13 months, the occurrence rate of AFib progressively increased up to 32.9% at the end of follow-up. The median occurrence time for AFib was 8 months. AFib occurrence was significantly associated with previous AFib history (P=0.01) but not with the presence of underlying heart disease (P=n.s.). Of particular interest, in our study, AFib never occurred in patients without previous AFib history. Palpitations after chronic common atrial flutter ablation was mostly related to AFib. Conclusion. In conclusion, after chronic common atrial flutter ablation, AFib incidence progressively increased over the follow-up in all patients. Patients with prior AFib history appeared to be a very high risk group. In these patients, closer monitoring is mandatory and the persistent risk of AFib recurrences may justify prolonged anticoagulation policy

    Clinical review: Bedside assessment of alveolar recruitment

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    Recruitment is a dynamic physiological process that refers to the reopening of previously gasless lung units. Cumulating evidence has led to a better understanding of the rules that govern both recruitment and derecruitment during mechanical ventilation of patients with acute respiratory distress syndrome. Therefore not only the positive end-expiratory pressure, but also the tidal volume, the inspired oxygen fraction, repeated tracheal suctioning as well as sedation and paralysis may affect recruitment of acute respiratory distress syndrome lungs that are particularly prone to alveolar instability. In the present article, we review the recently reported data concerning the physiological significance of the pressure–volume curve and its use to assess alveolar recruitment. We also describe alternate techniques that have been proposed to assess recruitment at the bedside. Whether recruitment should be optimized remains an ongoing controversy that warrants further clinical investigation

    What is preventing dentists from providing person-centred care?

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    Most healthcare professions have shifted the way they teach clinical approaches from a biomedical to a person-centred perspective. Yet, dentistry remains strongly anchored in a biomedical world.The objective of this project was to understand the barriers practicing dentists face to provide what we consider person-centred care. We conducted a qualitative descriptive study that comprised semi-structured interviews with dentists in private practice in the Greater Montreal area. After the analysis, we identified six barriers:•     Fear of interpersonal conflict: participants thought that engaging in genuine conversations with patients would lead to situations of disagreement and even conflicts.•     Fear of litigation: dentists considered that the legal and licensing infrastructure would judge the treatment they provide through a strict biomedical framework.•     Fear of loss of money: participants thought that providing person-centred care was more time consuming and thus financially penalizing. •    Pleasure to excel technically: some dentists did not consider offering interventions that provided less procedural pleasure than technical ones.•    Narrow interpretation of health: participants considered the biomedical dimension as the only important dimension.•    Lack of information: participants knew nothing or very little about person or patient-centred care. They seemed willing to integrate it into their practice had they had known more about it.These findings should help academic institutions to design their programs on person-centred care and respond to the fears expressed by professionals.Also, legal infrastructures must recognize the paradigm shift from the biomedical to the person-centred.

    Bacterial toxins modifying the actin cytoskeleton

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    Numerous bacterial toxins recognize the actin cytoskeleton as a target. The clostridial binary toxins (Iota and C2 families) ADP-ribosylate the actin monomers causing the dissociation of the actin filaments. The large clostridial toxins from Clostridium difficile, Clostridium sordellii and Clostridium novyi inactivate, by glucosylation, proteins from the Rho family that regulate actin polymerization. In contrast, the cytotoxic necrotic factor from Escherichia coli activates Rho by deamidation and increases the formation of actin filaments. The enterotoxin of Bacteroides fragilis is a protease specific for E-cadherin and it promotes the reorganization of the actin cytoskeleton. The bacterial toxins that modify the actin cytoskeleton induce various cell disfunctions including changes in cell barrier permeability and disruption of intercellular junctions

    Membrane Reactor Based on Hybrid Nanomaterials for Process Intensification of Catalytic Hydrogenation Reaction: an Example of Reduction of the Environmental Footprint of Chemical Synthesis from a Batch to a Continuous Flow Chemistry Process

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    Membrane processes represent a well matured technology for water treatment with low environmental footprints compared to other type of processes. We have now combined this technology with nanomaterials, ionic liquids (negligible vapor pressure), and poly(ionic liquids) in order to enlarge the field of applications while benefiting from the advantages of membranes. We have modified flat sheet water filtration membrane and used it as both catalytic support and reactor with the advantages to make the reaction and the separation of products in only one step. For this purpose, catalytic metallic nanoparticles of palladium (diameter of ca. 2 nm) were synthesized in a gel-poly(ionic liquid) layer grafted at the surface of polymeric filtration membranes by UV-photografting method. The so obtained catalytic membrane was successfully applied in the hydrogenation of trans-4-phenyl-3-buten-2-one in forced flow-through configuration, which gave full conversion in a few seconds (2.6 s) showing advantages over the batch reactor process (in that case, palladium nanoparticles were synthesized in the ionic liquid [MMPIM][NTf2] (1,2-dimethyl-3-propylimidazolium bis-(trifluoromethylsulfonyl)imide)). Nevertheless, the catalytic membrane used in submerged mode no more prevailed over the batch reactor. Catalytic nanoparticles remain highly active in the membrane after 12 cycles of reaction without need of recuperation. Results were compared to one obtains with a similar system in batch reactor conditions, showing high efficiency of our process in term of selectivity and reactivity, combined to an important compactness, the productivity of the catalytic hollow fiber membrane reactor and permitting to operate at larger scale with promising results in an environmental friendly way in term of energy and product (metal, solvent) consuming

    TANGO: Transparent heterogeneous hardware Architecture deployment for eNergy Gain in Operation

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    The paper is concerned with the issue of how software systems actually use Heterogeneous Parallel Architectures (HPAs), with the goal of optimizing power consumption on these resources. It argues the need for novel methods and tools to support software developers aiming to optimise power consumption resulting from designing, developing, deploying and running software on HPAs, while maintaining other quality aspects of software to adequate and agreed levels. To do so, a reference architecture to support energy efficiency at application construction, deployment, and operation is discussed, as well as its implementation and evaluation plans.Comment: Part of the Program Transformation for Programmability in Heterogeneous Architectures (PROHA) workshop, Barcelona, Spain, 12th March 2016, 7 pages, LaTeX, 3 PNG figure

    A three-thousand-year history of vegetation and human impact in Burgundy (France) reconstructed from pollen and non-pollen palynomophs analysis

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    International audienceThis article presents a 241 cm long sediment record documenting the vegetation history using previous termpollen and non-pollennext term palynomorphs recovered from the Fénay marsh in Burgundy (Dijon area – previous termFrance). The pollen and non-pollennext term palynomorphs (NPP) record largely reflects intensive human influence (clearing, cultivation and grazing) on the surrounding area from the Late Bronze Age and Hallstatt period. La Tène period is marked by drier conditions and a substantial increase in Alnus. During the Gallo-Roman period, high values of Alnus decrease to the benefit of Quercus. In the Early Middle Ages (5th–10th C), the swamp becomes a temporary pond and Cerealia type and Secale are cultivated in this very open landscape. During the Late Middle Ages (13th–15th C), the temporary pond is transformed into a larger and deeper pond, used by the Cistercians for hydraulic power and perhaps as a hemp-retting pit. By the end of the 16th C, the pond had dried out and was used for the cultivation of cereal

    L2-stability criterion for systems with decentralized asynchronous controllers

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    International audienceThis paper deals with the stability analysis of decentralized sampled-data Linear Time Invariant (LTI) control systems with asynchronous sensors and actuators. We consider the case where each controller in the decentralized setting has its own sampling and actuation frequency which translates to asynchrony between sensors and actuators. The errors induced due to sampling and asynchronicity are modelled using two different operator approaches, leading to simple L2-stability criteria for the overall decentralized control system. The simplicity of the obtained criteria is illustrated by an example and simulation results exhibit the effectiveness of the approach
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