Micro-Nano : des comportements différents, des procédés à adapter

6 pagesL'arrivée de nanomatériaux parmi les différents matériaux utilisés en pyrotechnie pose de nombreux problèmes de mise en œuvre. En effet, leurs propriétés texturales particulières ne permettent pas de les utiliser comme des matériaux classiques. Il est impératif d'adapter les procédés de mise en œuvre habituels. Pour obtenir l'adéquation de ces nouveaux matériaux et de nos procédés, des études spécifiques du comportement des nanomatériaux au cours des procédés de mise en œuvre par coulée ont été réalisés. L'observation des écarts de comportement des nanomatériaux par rapport aux "micro-matériaux" pour une même nature chimique et des conditions identiques de mise en œuvre permet d'établir des lois de comportement spécifiques, fonction de la taille des particules manipulées. Les mentalités, comme les procédés, doivent évoluer et prendre en compte l'élévation de surface spécifique qu'offre le passage à l'échelle nanométrique. Ainsi un chargement moindre en nanomatériaux ne sera pas forcement synonyme de lacunes sur les caractéristiques du produit fini (propriétés mécaniques ou pyrotechniques). Deux questions peuvent alors se poser : faut-il adapter les formulations aux procédés, en prenant en compte les caractéristiques des matières premières ou bien adapter des procédés devant supporter des taux de chargement élevés en nanomatériaux ? Le manque de connaissance et le recul sur le comportement des nanomatériaux sont un frein à leur intégration dans des composés pyrotechniques mais les propriétés exhibées laissent présagées d'un grand intérêt en vue de l'optimisation des propriétés des composés fabriqués

Five-Year Outcomes after Off-Pump or On-Pump Coronary-Artery Bypass Grafting.

BACKGROUND: We previously reported that there was no significant difference at 30 days or at 1 year in the rate of the composite outcome of death, stroke, myocardial infarction, or renal failure between patients who underwent coronary-artery bypass grafting (CABG) performed with a beating-heart technique (off-pump) and those who underwent CABG performed with cardiopulmonary bypass (on-pump). We now report the results at 5 years (the end of the trial). METHODS: A total of 4752 patients (from 19 countries) who had coronary artery disease were randomly assigned to undergo off-pump or on-pump CABG. For this report, we analyzed a composite outcome of death, stroke, myocardial infarction, renal failure, or repeat coronary revascularization (either CABG or percutaneous coronary intervention). The mean follow-up period was 4.8 years. RESULTS: There were no significant differences between the off-pump group and the on-pump group in the rate of the composite outcome (23.1% and 23.6%, respectively; hazard ratio with off-pump CABG, 0.98; 95% confidence interval [CI], 0.87 to 1.10; P=0.72) or in the rates of the components of the outcome, including repeat coronary revascularization, which was performed in 2.8% of the patients in the off-pump group and in 2.3% of the patients in the on-pump group (hazard ratio, 1.21; 95% CI, 0.85 to 1.73; P=0.29). The secondary outcome for the overall period of the trial - the mean cost in U.S. dollars per patient - also did not differ significantly between the off-pump group and the on-pump group ($15,107 and$14,992, respectively; between-group difference, $115; 95$697 to $927). There were no significant between-group differences in quality-of-life measures. CONCLUSIONS: In our trial, the rate of the composite outcome of death, stroke, myocardial infarction, renal failure, or repeat revascularization at 5 years of follow-up was similar among patients who underwent off-pump CABG and those who underwent on-pump CABG. (Funded by the Canadian Institutes of Health Research; CORONARY ClinicalTrials.gov number, NCT00463294 .)

Etude physico-chimique d'un composé pyrotechnique (mise en oeuvre, modélisation et sécurisation)

Les milieux granulaires sont présents à toutes les échelles et dans de nombreux domaines d'activité. La connaissance et la compréhension du comportement de ces milieux sous diverses sollicitations sont donc d'un grand intérêt, aussi bien pour des raisons scientifiques, techniques qu'économiques. Nous tentons tout d'abord de comprendre les interactions entre les propriétés physico-chimiques des matériaux granulaires et leurs propriétés de mise en œuvre par compression uniaxiale. L'analyse nous conduit à l'élaboration de lois de mélanges permettant de prédire le comportement d'un mélange à partir de la connaissance des propriétés de ces différents constituants. Le soucis de compréhension nous conduit à la modélisation par quasi-chimie et à la simulation par éléments finis et automates cellulaires : la pertinence des automates cellulaires nous pousse à continuer les travaux dans le domaine des sciences de la complexité.ORLEANS-BU Sciences (452342104) / SudocSudocFranceF

Modeling the Porosity Evolution of a Powder under Uniaxial Compression

International audienceThe purpose of this work is to present a new model describing the evolution of powder porosity versus applied pressure during uniaxial compression. This model is based on quasi-chemical treatments and population balances. It is generally admitted that compression is composed of four steps: a first reorganization of the initial particles, a fragmentation of some initial particles, a second rearrangement of the initial and secondary particle mixture and a plastic deformation stage. So the model is constructed around these four steps. Experimental results on eighteen different powders show a fair agreement with theoretical results and material physical constant values. The use of this model can allow classifying the reorganization, fragmentation and plastic deformation abilities of the products and it will be useful in order to optimize the elaboration process

PET-adapted treatment for newly diagnosed advanced Hodgkin lymphoma (AHL2011): a randomised, multicentre, non-inferiority, phase 3 study

International audienceIncreased-dose bleomycin, etoposide, doxorubicin, cyclophosphamide, vincristine, procarbazine, and prednisone (BEACOPPescalated) improves progression-free survival in patients with advanced Hodgkin lymphoma compared with doxorubicin, bleomycin, vinblastine, and dacarbazine (ABVD), but is associated with increased risks of haematological toxicity, secondary myelodysplasia or leukaemia, and infertility. We investigated whether PET monitoring during treatment could allow dose de-escalation by switching regimen (BEACOPPescalated to ABVD) in early responders without loss of disease control compared with standard treatment without PET monitoring.Programme Hospitalier de Recherche Clinique

A simplified scoring system in de novo follicular lymphoma treated initially with immunochemotherapy.

In follicular lymphoma (FL), no prognostic index has been built based solely on a cohort of patients treated with initial immunochemotherapy. There is currently a need to define parsimonious clinical models for trial stratification and to add on biomolecular factors. Here, we confirmed the validity of both the follicular lymphoma international prognostic index (FLIPI) and the FLIPI2 in the large prospective PRIMA trial cohort of 1135 patients treated with initial R-chemotherapy ± R maintenance. Furthermore, we developed a new prognostic tool comprising only 2 simple parameters (bone marrow involvement and β-microglobulin [βm]) to predict progression-free survival (PFS). The final simplified score, called the PRIMA-PI (PRIMA-prognostic index), comprised 3 risk categories: high (βm > 3 mg/L), low (βm ≤ 3 mg/L without bone marrow involvement), and intermediate (βm ≤ 3 mg/L with bone marrow involvement). Five-year PFS rates were 69%, 55%, and 37% in the low-, intermediate-, and high-risk groups, respectively ( < .0001). In addition, achieving event-free survival (EFS) or not at 24 months (EFS24) was a strong posttreatment prognostic parameter for subsequent overall survival, and the PRIMA-PI was correlated with EFS24. The results were confirmed in a pooled external validation cohort of 479 patients from the FL2000 LYSA trial and the University of Iowa/Mayo Clinic Lymphoma Specialized Program of Research Excellence Molecular Epidemiology Resource. Five-year EFS in the validation cohort was 77%, 57%, and 44% in the PRIMA-PI low-, intermediate-, and high-risk groups, respectively ( < .0001). The PRIMA-PI is a novel and easy-to-compute prognostic index for patients initially treated with immunochemotherapy. This could serve as a basis for building more sophisticated and integrated biomolecular scores

PET-adapted treatment for newly diagnosed advanced Hodgkin lymphoma (AHL2011): a randomised, multicentre, non-inferiority, phase 3 study

International audienceBackground: Increased-dose bleomycin, etoposide, doxorubicin, cyclophosphamide, vincristine, procarbazine, and prednisone (BEACOPPescalated) improves progression-free survival in patients with advanced Hodgkin lymphoma compared with doxorubicin, bleomycin, vinblastine, and dacarbazine (ABVD), but is associated with increased risks of haematological toxicity, secondary myelodysplasia or leukaemia, and infertility. We investigated whether PET monitoring during treatment could allow dose de-escalation by switching regimen (BEACOPPescalated to ABVD) in early responders without loss of disease control compared with standard treatment without PET monitoring.Methods: AHL2011 is a randomised, non-inferiority, phase 3 study done in 90 centres across Belgium and France. Eligible patients were aged 16-60 years and had newly diagnosed Hodgkin lymphoma, excluding nodular lymphocyte predominant subtype, an Eastern Cooperative Oncology Group performance status score less than 3, a life expectancy of at least 3 months, an Ann Arbor disease stage III, IV, or IIB with mediastinum-to-thorax ratio of 0·33 or greater than or extranodal localisation, and had received no previous treatment for Hodgkin lymphoma. Randomisation was unmasked and done centrally by the permuted block method. Patients were randomly assigned to standard treatment (BEACOPPescalated given every 21 days for six cycles) or PET-driven treatment. All patients received two cycles of upfront BEACOPPescalated, after which PET assessment was done (PET2). In the standard treatment group, PET2 patients completed two additional cycles of BEACOPPescalated induction therapy irrespective of PET2 findings. In the PET-driven treatment group, patients with positive PET2 scans received the further two cycles of BEACOPPescalated and those with a negative PET2 scan switched to two cycles of ABVD for the remaining induction therapy. In both treatment groups, PET at the end of induction therapy was used to decide whether to continue with consolidation therapy in those with negative scans or start salvage therapy in patients with positive scans (either two cycles of ABVD in PET2-negative patients in the PET-driven arm or two cycles of BEACOPPescalated). BEACOPPescalated consisted of bleomycin 10 mg/m2 and vincristine 1·4 mg/m2 intravenously on day 8, etoposide 200 mg/m2 intravenously on days 1-3, doxorubicin 35 mg/m2 and cyclophosphamide 1250 mg/m2 intravenously on day 1, 100 mg/m2 oral procarbazine on days 1-7, and 40 mg/m2 oral prednisone on days 1-14. ABVD was given every 28 days (doxorubicin 25 mg/m2, bleomycin 10 mg/m2, vinblastine 6 mg/m2, and dacarbazine 375 mg/m2 intravenously on days 1 and 15). The primary endpoint was investigator-assessed progression-free survival. Non-inferiority analyses were done by intention to treat and per protocol. The study had a non-inferiority margin of 10%, to show non-inferiority of PET-guided treatment versus standard care with 80% power and an alpha of 2·5% (one-sided). This study is registered with ClinicalTrials.gov, number NCT01358747.Findings: From May 19, 2011, to April 29, 2014, 823 patients were enrolled-413 in the standard care group and 410 in the PET-driven group. 346 (84%) of 410 patients in the PET-driven treatment group were assigned to receive ABVD and 51 (12%) to continue receiving BEACOPPescalated after PET2. With a median follow-up of 50·4 months (IQR 42·9-59·3), 5-year progression-free survival by intention to treat was 86·2%, 95% CI 81·6-89·8 in the standard treatment group versus 85·7%, 81·4-89·1 in the PET-driven treatment group (hazard ratio [HR] 1·084, 95% CI 0·737-1·596; p=0·65) and per protocol the values were 86·7%, 95% CI 81·9-90·3 and 85·4%, 80·7-89·0, respectively (HR 1·144, 0·758-1·726; p=0·74). The most common grade 3-4 adverse events were leucopenia (381 [92%] in the standard treatment group and 387 [95%] in the PET-driven treatment group), neutropenia (359 [87%] and 366 [90%]), anaemia (286 [69%] vs 114 [28%]), thrombocytopenia (271 [66%] and 163 [40%]), febrile neutropenia (145 [35%] and 93 [23%]), infections (88 [22%] and 47 [11%]), and gastrointestinal disorders (49 [11%] and 48 [11%]). Serious adverse events related to treatment were reported in 192 (47%) patients in the standard treatment group and 114 (28%) in the PET-driven treatment group, including infections (84 [20%] of 412 vs 50 [12%] of 407) and febrile neutropenia (21 [5%] vs 23 [6%]). Six (1%) patients in the standard care group died from treatment-related causes (two from septic shock, two from pneumopathy, one from heart failure, and one from acute myeloblastic leukaemia), as did two (<1%) in the PET-driven treatment group (one from septic shock and one from acute myeloblastic leukaemia).Interpretation: PET after two cycles of induction BEACOPPescalated chemotherapy safely guided treatment in patients with advanced Hodgkin lymphoma and allowed the use of ABVD in early responders without impairing disease control and reduced toxicities. PET staging allowed accurate monitoring of treatment in this trial and could be considered as a strategy for the routine management of patients with advanced Hodgkin lymphoma