Educing coherent eddy structures in air curtain systems

The work reported here comes within a broader research program dealing with ambiance separation or confining by means of air curtains (plane air jets). The process is studied experimentally by Particle Image Velocimetry (PIV). In this paper, the emphasis is put on the flow structure in the impingement region of such jet systems insofar as it is where transfers occur preferentially. More precisely, a vortex eduction method was implemented under the Matlab environment enabling both the automatic detection of 2D coherent patterns embedded in PIV velocity vector maps, and a statistical analysis of the topological and energy features of these structures. First, the approach is explained in detail. The second part of this paper is devoted to its application in the case of plane turbulent impinging simple- and twin-jets for various jet exit velocities. Results about the size, the shape, the spatial distribution and the energy content of the detected vortices are provided. Although many questions still remain open, new insights into the fashion these structures might form, organize and evolve are given providing an original picture of the plane turbulent impinging jet

Major bleeding risk and mortality associated with antiplatelet drugs in real-world clinical practice. A prospective cohort study

International audienceBackground - Major bleedings other than gastrointestinal (GI) and intracranial (ICH) and mortality rates associated with antiplatelet drugs in real-world clinical practice are unknown. The objective was to estimate major bleeding risk and mortality among new users of antiplatelet drugs in real-world clinical practice. Methods and findings - A population-based prospective cohort using the French national health data system (SNIIRAM), identified 69,911 adults living within five well-defined geographical areas, who were new users of antiplatelet drugs in 2013-2015 and who had not received any antithrombotics in 2012. Among them, 63,600 started a monotherapy and 6,311 a dual regimen. Clinical data for all adults referred for bleeding was collected from all emergency departments within these areas, and medically validated. Databases were linked using common key variables. The main outcome measure was time to major bleeding (GI, ICH and other bleedings). Secondary outcomes were death, and event-free survival (EFS). Hazard ratios (HR) were derived from adjusted Cox proportional hazard models. We used Inverse Propensity of Treatment Weighting as a stratified sensitivity analysis according to the antiplatelet monotherapy indication: primary prevention without cardiovascular (CV) risk factors, with CV risk factors, and secondary prevention. We observed 250 (0.36%) major haemorrhages, 81 ICH, 106 GI and 63 other types of bleeding. Incidences were twice as high in dual therapy as in monotherapy. Compared to low-dose aspirin (≤ 100 mg daily), high-dose (> 100 up to 325 mg daily) was associated with an increased risk of ICH (HR = 1.80, 95%CI 1.10 to 2.95). EFS was improved by high-dose compared to low-dose aspirin (1.41, 1.04 to 1.90 and 1.32, 1.03 to 1.68) and clopidogrel (1.30, 0.73 to 2.3 and 1.7, 1.24 to 2.34) respectively in primary prevention with and without CV risk factors. Conclusion - The incidence of major bleeding and mortality was low. In monotherapy, low-dose aspirin was the safest therapeutic option whatever the indication. Trial registration - NCT02886533

Management of epistaxis associated with oral antithrombotic drugs in emergency department and impact on prescription thereafter

International audienceOBJECTIVES: To describe management, and to assess factors associated with antithrombotic prescription thereafter in patients who had epistaxis referred to emergency department (ED). DESIGN: Prospective cohort study. From EDs, clinical, biological and hospital data were collected. The clinical database was linked to the French Health Insurance Database where we retrieved antithrombotic drug deliveries in a 3-month period before and after referral. SETTING: Multicentric population-based cohort study within five well-defined areas. PARTICIPANTS: We considered 306 patients referred for epistaxis with a stable oral antithrombotic regimen before referral. MAIN OUTCOME MEASURES: We considered management, hospital outcome and case fatality. Antithrombotic prescription in a 3-month follow-up period was categorised into three classes: no change, class change, or discontinuation. During follow-up, hospitalisation for epistaxis or ischaemic events was searched. RESULTS: Among 306 adult individuals (mean age: 76 years), 166 took oral anticoagulant and 140 an antiplatelet drug. Blood transfusion was needed in 13.7% of patients and anterior packing alone in 61%. Half of the patients were hospitalised; 301 were discharged alive. Considering antithrombotic prescription thereafter we observed no change in 219 patients (72.8%), class changes in 47 patients (15.6%) and discontinuation in 35 patients (11.6%). We identified four independent predictors for antithrombotic prescription: hospitalisation (vs. returning home, p = .05), age (p = .03), haemoglobin level (p = .03) and oral anticoagulant (vs. antiplatelet agent, p < .001). During the 3 months following discharge, 2 thrombotic and 15 bleeding events were identified. CONCLUSIONS: Epistaxis referred to emergency department had an impact on subsequent antithrombotic prescription. CLINICAL TRIAL REGISTRATION: Clinical Trials.gov identifier: NCT02886533

Acute, major muscular hematoma associated with antithrombotic agents: A multicenter real-world cohort

International audienceBACKGROUND: There is little data on major muscular hematomas and the little there is has mainly focused on patients exposed to oral anticoagulants. OBJECTIVE: To describe the clinical characteristics, management and outcomes of patients admitted to emergency department (ED) for major muscular hematoma associated with an antithrombotic agent, and to identify predictors of in-hospital mortality. PATIENTS AND METHODS: Over a three-year period, all consecutive cases of adult patients admitted to the ED of 5 tertiary care hospitals for major muscular hematoma while exposed to an antithrombotic agent were prospectively collected and medically validated. Clinical and biological data, therapeutic management of the bleeding event, and in-hospital mortality were collected from the medical records and compared across five groups of hematoma locations. Potential confounders were taken in account using a multivariate binomial regression model. RESULTS: Three hundred and seventy-five patients were included (mean age = 81.4 years): 271 were exposed to vitamin K antagonists, 58 to parenteral anticoagulants (heparin, LMWH, fondaparinux), 33 to antiplatelets, and 13 to direct oral anticoagulants. The muscular hematomas were located in the lower limbs (n = 198), the rectus sheath (n = 71), the iliopsoas (n = 45), the upper limbs (n = 33), or elsewhere (n = 28). Reversal therapy was prescribed for 48.5% of patients, red cell transfusions for 63.6%, surgery for 12.3% and embolization for 3.5%. For 84% of patients, hospitalization was required, with a median length of stay of 10 days. Overall, in-hospital mortality was 8.5%. Reversal therapy, the need for intensive care and mortality were significantly more frequent among patients with iliopsoas hematomas. The independent predictors of in-hospital mortality were: decrease in mean arterial pressure (RR = 1.84), decrease in hemoglobin level (RR = 1.37) and the iliopsoas location (RR = 3.06). CONCLUSION: Frail elderly patients with major muscular hematomas linked to antithrombotic agents risk substantial morbidity and in-hospital mortality. The iliopsoas location was the most life-threatening bleeding site. Close observation of this population is warranted to ensure better outcomes

Clinical use of low-dose parenteral anticoagulation, incidence of major bleeding and mortality: a multi-centre cohort study using the French national health data system

International audiencePurpose Low-dose parenteral anticoagulation has demonstrated its efficacy for venous thromboembolism prophylaxis in randomized trials. However, current practice is not widely documented. In ambulatory settings, we aimed to provide an overview of the clinical use of low-dose parenteral anticoagulation in France and to assess the incidence of major bleeding and death rates. Methods A population-based prospective cohort study using the French national health data system (SNIIRAM) identified 142,815 adults living in five well-defined geographical areas who had a course of low-dose parenteral anticoagulants (a total of 150,389 courses) in the period 2013-2015. The main outcome measures were the types of low-dose parenteral anticoagulant, the duration and the clinical context. Adjusted incidence rate ratios (IRR) were derived from Poisson models. Results Enoxaparin was the most frequently prescribed anticoagulant (58.9%) followed by tinzaparin (27.3%) and fondaparinux (10.9%). Patients receiving unfractionated heparin (N= 766, 0.53%) were older, more frequently had renal disease (48.75%) and had a higher modified HAS-B(L)ED score (>= 3 in 61.6%) than patients receiving low-molecular weight heparin (LMWH). Surgical thrombo-prophylaxis was the most frequent indication (47.6%), followed by medical prophylaxis (29.9%). Course durations were in line with regulatory agency specifications. Only 43 (0.028%) major bleeding events and 478 (0.32%) deaths were observed. Adjusted IRRs for major bleeding or death were not significantly different for dalteparin/nadroparin, tinzaparin or fondaparinux compared to enoxaparin. Conclusion Very low incidence rates of major bleeding and all-cause mortality were observed. Our study confirms the safety of LMWHs and fondaparinux in thrombo-prophylaxis in ambulatory settings

Major bleeding risk associated with oral anticoagulant in real clinical practice. A multicentre 3-year period population-based prospective cohort study

International audienceAims: The objective was to compare major bleeding risk of direct oral anticoagulants (DOACs; per type and dose) with vitamin K antagonists (VKAs), irrespective of indication, using real-world data.Methods: A population-based prospective cohort study, using the French national health data system (SNIIRAM), identified 47 469 adults living within 5 well-defined geographical areas, who were new users of oral anticoagulants in the period 2013-2015: 20 205 VKA users, 19 579 rivaroxaban users, 4225 dabigatran users and 3460 apixaban users. From all emergency departments within these areas, clinical data for all adults referred for bleeding was collected and medically validated. The databases were linked for common key variables. The main outcome measure was major bleeding: intracranial haemorrhage, major gastrointestinal bleeding and other major bleeding events. Hazard ratios were derived from adjusted Cox proportional hazard models. We used propensity score weighting as a sensitivity analysis, with separate analyses according to indications (atrial fibrillation or venous thromboembolism).Results: Compared to VKAs, high and low-dose DOACs were associated with a reduced risk of intracranial haemorrhage (adjusted hazard ratio 0.55, 95% confidence interval 0.37-0.82 and 0.54, 0.26-1.12 respectively), and a reduced risk of other major bleeding events (0.41, 0.29-0.58 and 0.41, 0.22-0.79 respectively), irrespective of duration and indication. Neither DOAC dose evidenced any significant difference from VKAs in terms of risk of major gastrointestinal bleeding.Conclusion: There is a clear benefit of using DOACs with regard to intracranial haemorrhage. The study provides new insight into major gastrointestinal and other major bleeding events

Major bleeding risk associated with Oral anticoagulant in real clinical practice. A multicentre population-based prospective cohort study over a period years

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Click-electrochemistry for the rapid labeling of virus, bacteria and cell surfaces

The remodeling of microorganism surfaces with biomolecules is a powerful tool to study the role of membrane receptors in chemical biology and to develop drug delivery systems in gene therapy using viral vectors and cell-based therapies. Methods for direct covalent ligation of these surfaces remain poorly reported, and mostly based on metabolic engineering for bacteria and cells functionalization. In the latter case, a tagged precursor must first be enzymatically metabolized and delivered to the outer cell membrane to become available for chemo-selective labeling. While effective, a faster method avoiding the bio-incorporation step would be highly complementary. This would also need to be compatible with organisms showing poor levels of precursor assimilation or lacking the metabolic function. Here, we used N-methylluminol (NML), a fully tyrosine-selective protein anchoring group after one-electron oxidation, to label the surface of viruses, living bacteria and cells. The functionalization was performed electrochemically and in situ by applying a 750 mV vs Ag/AgCl electric potential to aqueous buffered solutions of tagged NML containing the viruses, bacteria or cells. The electro-coupling was performed with NML anchors bearing a bioorthogonal azide, biotin, or carbohydrate (mannose and N-acetyl galactosamine) handles. The broad applicability of the click-electrochemistry method was explored on recombinant adeno-associated viruses (rAAV2), E. coli (Gram-) and S. epidermis (Gram+) bacterial strains, and HEK293 and HeLa eukaryotic cell lines. Surface electro-conjugation was achieved in minutes to yield functionalized rAAV2 that conserved both structural integrity and infectivity properties, and living bacteria and cell lines that were still alive and able to divide. As NML activation immediately stops if there is no current, the method offers reproducible temporal control on the degree of surface functionalization. Thus, click-electrochemistry should significantly expand the scope of bioconjugation methods

Click-electrochemistry for the rapid labeling of virus, bacteria and cell surfaces

Abstract Methods for direct covalent ligation of microorganism surfaces remain poorly reported, and mostly based on metabolic engineering for bacteria and cells functionalization. While effective, a faster method avoiding the bio-incorporation step would be highly complementary. Here, we used N-methylluminol (NML), a fully tyrosine-selective protein anchoring group after one-electron oxidation, to label the surface of viruses, living bacteria and cells. The functionalization was performed electrochemically and in situ by applying an electric potential to aqueous buffered solutions of tagged NML containing the viruses, bacteria or cells. The broad applicability of the click-electrochemistry method was explored on recombinant adeno-associated viruses (rAAV2), Escherichia coli (Gram-) and Staphyloccocus epidermidis (Gram + ) bacterial strains, and HEK293 and HeLa eukaryotic cell lines. Surface electro-conjugation was achieved in minutes to yield functionalized rAAV2 that conserved both structural integrity and infectivity properties, and living bacteria and cell lines that were still alive and able to divide

Novel chemical tyrosine functionalization of adeno-associated virus improves gene transfer efficiency in liver and retina

Decades of biological and clinical research have led to important advances in recombinant adeno-associated viruses rAAV-based gene therapy gene therapy. However, several challenges must be overcome to fully exploit the potential of rAAV vectors. Innovative approaches to modify viral genome and capsid elements have been used to overcome issues such as unwanted immune responses and off-targeting. While often successful, genetic modification of capsids can drastically reduce vector yield and often fails to produce vectors with properties that translate across species. Here, we describe a chemical bioconjugation strategy to modify tyrosine residues on AAV capsids using specific ligands, thereby circumventing the need to genetically engineer the capsid sequence. Aromatic electrophilic substitution of the phenol ring of tyrosine residues on AAV capsids improved the in vivo transduction efficiency of rAAV2 vectors in both liver and retinal targets. This tyrosine bioconjugation strategy represents an innovative technology for the engineering of rAAV vectors for human gene therapy