9 results on '"Martin, Sylvain"'
Search Results
2. Inverse Population Balance Problems: Heuristics for Aggregation/Breakage of Solid Clusters in Liquid Metals
- Author
-
Auger, Jean-Marc, Martin, Sylvain, and Gruy, Frédéric
- Abstract
Population balance models have been applied to the simultaneous aggregation and breakage of solid clusters in agitated liquid metals. Challenges in these systems lie in determination of kinetic constants (kernels) from measurements of experimental cluster concentrations. However, due to difficulties inherent to molten metal experimentation (severely limiting available data points and replication) and lack of literature concerning the physical phenomena involved, more advanced inverse methods are needed. Taking into account physical characteristics, theoretical approaches using reaction networks proved the existence of at least one stable positive equilibrium state. This result allowed the construction of two distinct fitting algorithms, aimed at solving the corresponding inverse problem (kernel determination from experimental data). The first of these heuristic methods accurately identifies kernel parameters from perfect steady-state data, while the second, based on transitory states, reliably leads to correct results with as few data points as 2 and measurement errors as high as 5%.
- Published
- 2020
- Full Text
- View/download PDF
3. Comparative study of 3 exophthalmometers and computed tomographic biometry
- Author
-
Delmas, Juliette, Loustau, Jean-Marie, Martin, Sylvain, Bourmault, Loïc, Adenis, Jean-Paul, and Robert, Pierre-Yves
- Abstract
Purpose: Accurate and reproducible exophthalmometry is mandatory to diagnose and follow-up orbital patients, especially in Graves disease. However, many variations are described among the different commercially available exophthalmometers.Methods: Sixty patients, who underwent a cerebral computed tomography (CT) scan, were included. External prebicanthal segments (EPBCS) for right and left eyes (RE and LE), interorbital distance, and globe axial length were recorded by a first observer (O1), more experienced than a second (O2). Intraobserver and interobserver reproducibility were evaluated, using intraclass correlation coefficient (ICC) and Bland and Altman plots.Results: Concordance between each EPBCS measurement for each eye and CT scan biometry was moderate for the Luedde ruler for the 2 observers. For the Hertel exophthalmometer, concordance was moderate for O1 in the 2 eyes and moderate in RE but good in LE for O2. For the Mourits exophthalmometer, this concordance was very good in RE and good in LE for O1, and good whatever the eye for O2. Intraobserver (ICC varying from 0.75 to 0.95 for the 2 observers) and interobserver (ICC from 0.69 to 0.94) reproducibility were high, especially for the Mourits exophthalmometer. Bland and Altman plots showed underestimations when using the Luedde ruler, overestimations when using the Hertel exophthalmometer, and overestimation of small values and underestimation of high values when using the Mourits exophthalmometer when compared to CT scan biometry.Conclusions: We demonstrated great accuracy to CT scan biometry with 1-prism Mourits exophthalmometer, low accuracy with the Luedde instrument, and intermediate accuracy with the Hertel exophthalmometer, with fair intraobserver and interobserver reproducibility.
- Published
- 2018
- Full Text
- View/download PDF
4. Validation of DEM modeling of sintering using an in situ X-ray microtomography analysis of the sintering of NaCl powder
- Author
-
Martin, Sylvain, Navarro, Sebastián, Palancher, Hervé, Bonnin, Anne, Léchelle, Jacques, Guessasma, Mohamed, Fortin, Jérôme, and Saleh, Khashayar
- Abstract
This paper aims to validate the discrete element method (DEM) model of sintering. In situ X-ray microtomography experiments have been carried out at the ESRF to follow the sintering of NaCl powder, the properties of which are close to the DEM model assumptions. DEM simulations are then run using an improved implicit method. The comparison between experiment and simulation shows the capability of DEM to predict the behavior of the sample on both particle and packing scale. The main advantages and limits of this approach are finally discussed based on these results and those of previous studies.
- Published
- 2016
- Full Text
- View/download PDF
5. 0430: Assessment of systolic and diastolic features in light chain amyloidosis: an echocardiographic and cardiac magnetic resonance study.
- Author
-
Boulogne, Cyrille, Mohty, Dania, Magne, Julien, Damy, Thibaud, Echahidi, Najmeddine, Martin, Sylvain, Aboyans, Victor, and Jaccard, Arnaud
- Abstract
Background Cardiac involvement in systemic light-chain amyloidosis (AL) is characterized by 2D-echocardiography (TTE) normal or slithly decreased left ventricular (LV) ejection fraction and typically a diastolic dys-function with left atrial (LA) enlargement. To assess cardiac involvement, the Mayo Clinic staging (MC) using NTproBNP and troponin, has been validated and allows risk stratification of patients into 3 groups with different outcomes. Cardiac magnetic resonance (CMR) assesses accurately chambers size and function. We aimed to compare by TTE and by CMR respectively: features of LV systolic and diastolic function and by CMR, morphological functional parameters namely LV myocardial late gadolinium enhancement (LGE) and indexed max LA volume (LAVi) and emptying fraction (LAEF). Methods and results Forty-two consecutive patients (66±10 years, 57% males) in sinus rhythm with confirmed systemic AL, underwent simultaneously TTE and CMR within 24 hours. LAEF was calculated after assessing the maximal and minimal LAVi (by area/length formula) in CMR using 4 and 2 chambers views. Diastolic parameters and 2D-LV global longitudinal strain (GLS) obtained by TTE were stratified according to LAEF, to LAVi and to the presence or not of LGE. Patients in MC stage III had the worse TTE and CMR parameters. LV GLS (–10.1±3.1 vs. –17.3±3.7, p<0.001), mitral deceleration time, E/A ratio and lateral E/e’ ratio, were significantly altered in patients with low LAEF <17.5% (median value) vs. those with higher LAEF, whereas, they were not significantly different according to maximal LAVi. GLS was decreased in patients with LGE when compared to those without: –10.8 ±2.8% vs. –16.5±5.2%, p<0.0008. Conclusion In systemic AL, reduced LV GLS is associated with presence of LGE while impaired LV filling pressures are rather related to decreased LA emptying fraction. Multimodality imaging in patients with AL may allow better and complementary assessment of LV hemodynamics. Abstract 0430 - Table LA Emptying fraction CMR Maximal LAVICMR LGE <17.5% >17.5% p <44 ml/m 2 >44 ml/m 2 p – + p Mitral E/A ratio 2.98±1.82 0.89±0.28 <0.001 1.51±1.4 2.22±1.8 0.2 1.35±1.3 2.43±1.9 0.055 DT TTE (ms) 158±45 217±56 <0.001 190±65 183±53 0.7 219±51 145 ±39 <0.001 Lateral E/e’ 16.9±6.8 12.1±6.4 <0.04 14±7 14.8±7 0.8 13.6±7.4 15.7±6.4 0.4 GLS –10.1±3.1 –17.3±3.7 <0.001 –14.2±5 –12.7±4.6 0.4 –16.5±5.2 –10.8±2.8 <0.0008 [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
6. 43 Comparison of echocardiographic and cardiac magnetic resonance parameters in systemic light chain amyloidosis.
- Author
-
Boulogne, Cyrille, Mohty, Dania, Magne, Julien, Damy, Thibaud, Martin, Sylvain, Boncoeur, Marie-Paule, Aboyans, Victor, and Jaccard, Arnaud
- Published
- 2015
- Full Text
- View/download PDF
7. Prognostic value of left atrial function in systemic light-chain amyloidosis: a cardiac magnetic resonance study
- Author
-
Mohty, Dania, Boulogne, Cyrille, Magne, Julien, Varroud-Vial, Nicolas, Martin, Sylvain, Ettaif, Hind, Fadel, Bahaa M., Bridoux, Frank, Aboyans, Victor, Damy, Thibaud, and Jaccard, Arnaud
- Abstract
Background Cardiac involvement in systemic light-chain amyloidosis (AL) imparts an adverse impact on outcome. The left atrium (LA), by virtue of its anatomical location and muscular wall, is commonly affected by the amyloid process. Although LA infiltration by amyloid fibrils leads to a reduction in its pump function, the infiltration of the left ventricular (LV) myocardium results in diastolic dysfunction with subsequent increase in filling pressures and LA enlargement. Even though left atrial volume (LAV) is an independent prognostic marker in many cardiomyopathies, its value in amyloid heart disease remains to be determined. In addition, few data are available as to the prognostic value of LA function in systemic AL. Using cardiac magnetic resonance (CMR), the current study aims to assess the prognostic significance of the maximal LAV and total LA emptying fraction (LAEF) in patients with AL.Methods and results Fifty-four consecutive patients (age 66 ± 10 years, 59% males) with confirmed systemic AL and mean LV ejection fraction of 60 ± 12% underwent CMR. As compared with patients with no or minimal cardiac involvement (Mayo Clinic [MC] stage I), those at moderate and high risk (MC stages II and III) had significantly larger indexed maximal LAV (36 ± 15 vs. 46 ± 13 vs. 52 ± 19 mL/m2, P = 0.03) and indexed minimal LAV (20 ± 6 vs. 34 ± 11 vs. 44 ± 17 mL/m2, P < 0.001), lower LAEF (42 ± 9 vs. 26 ± 13 vs. 16 ± 9%, P < 0.0001) but similar LVEF. Furthermore, myocardial late gadolinium enhancement (LGE) was more frequent and significantly associated with lower LAEF. LAEF was also significantly lower in symptomatic (NHYA ≥ II, 22 ± 14%) as compared with asymptomatic patients (NYHA class I, 33 ± 13%, P = 0.006). Two-year survival rate was lower in patients with LAEF ≤ 16% as compared with those with LAEF > 16% (37 ± 11 vs. 94 ± 4%, P = 0.001). In multivariate analysis, lower LAEF remained independently associated with a higher risk of 2-year mortality (HR = 1.08 per 1% decrease, 95% CI: 1.02–1.15, P = 0.003).Conclusion In patients with systemic AL, LAEF as assessed by CMR is associated with NYHA functional class, MC stage, myocardial LGE and 2-year mortality.- Published
- 2016
- Full Text
- View/download PDF
8. Audit clinique sur le circuit du médicament en chirurgie programmée
- Author
-
Martin, Sylvain, Fessier, Claire, and Pingaud, Céline
- Abstract
Afin d’améliorer la prise en charge médicamenteuse des patients hospitalisés pour une chirurgie programmée, le questionnaire d’anesthésie destiné au patient (QP) et la fiche d’anesthésie (FA) ont été revus dans le cadre d’un groupe pluridisciplinaire courant 2013 (anesthésistes, pharmacien responsable du système de management de la qualité, gestionnaire des risques, soignants). Les documents modifiés sont en place depuis décembre 2013 et la FA sert désormais de support de prescription pour les médicaments à administrer avant le passage au bloc (traitement chronique du patient et prémédication). L’objectif de ce travail était dans un premier temps d’évaluer la bonne utilisation des nouveaux documents après 6 mois de mise en place et dans un deuxième temps la continuité de la prise en charge médicamenteuse du patient entre la ville et l’hôpital.
- Published
- 2014
- Full Text
- View/download PDF
9. Synchronization of high power vortex oscillators at multiple of the fundamental frequency
- Author
-
Baraduc, Claire, Martin, Sylvain, Thirion, Christophe, Liu, Yue, Dovek, Moris, and Diény, Bernard
- Abstract
RF vortex spin-transfer oscillators based on low RA magnetic tunnel junctions were investigated. A very high power of excitations has been obtained characterized by a power spectral density containing a very sharp peak at the fundamental frequency and a series of harmonics. The observed behaviour is attributed to the combined effect of Oersted-Ampère field generated by the large applied dc-current and of the spin transfer torque. We furthermore show the synchronization of a vortex oscillation by applying a RF bias microwave which frequency is twice the oscillator fundamental frequency.
- Published
- 2011
- Full Text
- View/download PDF
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.