Sylvie ETIENNE - Profile on Academia.edu (original) (raw)

Papers by Sylvie ETIENNE

ACS Sustainable Chemistry & Engineering, 2016

A new monolithic carbonaceous material, 750-HMF-CarboHIPE is presented here. The new electrode ha... more A new monolithic carbonaceous material, 750-HMF-CarboHIPE is presented here. The new electrode has been tested as an anode material inside a microbial bioelectrochemical system. In a purposely designed continuous flow bioelectrochemical reactor, the new material showed high biocompatibilty, with a continuous biofilm development that remained bioelectrochemically active for over 5 months. A catalytic current of 1.56 mA cm-2 / 7.8 mA cm-3 (normalization by projected surface area and volumetric current) was reached. The current density was proportional to the flow rate. The new electrode material was synthesized using a high internal phase emulsion (HIPE) as a soft template to confine the polymerization and hydrothermal carbonization of two precursors derived from the cellulosic fraction of biomass and the bark of fruit trees: respectively, 5-hydroxymethylfurfural and phloroglucinol. All together, the sustainable synthetic route from biomass materials and the proposed application of oxidizing organic matter present in wastewater to produce electricity in a microbial fuel cell (MFC) close an interesting loop of prospective sustainable technology.

Synthesis and characterization of a photosensitive organic–inorganic, hybrid positive resin type material: application to the manufacture of microfluidic devices by laser writing

RSC Adv., 2016

A chemically amplified photosensitive organic–inorganic hybrid material based on PAA polymer, TVE... more A chemically amplified photosensitive organic–inorganic hybrid material based on PAA polymer, TVEB as a crosslinking dissolution inhibitor, a VEPTES pre-hydrolysed as an organic–inorganic material and a PAG photoacid generator was developed.

Sets of silica gels: aerogels, xerogels and sintered aerogels, have been studied in the objective... more Sets of silica gels: aerogels, xerogels and sintered aerogels, have been studied in the objective to understand the mechanical behavior of these highly porous solids. The mechanical behaviour of gels is described in terms of elastic and brittle materials, like glasses or ceramics. The magnitude of the elastic and rupture modulus is several orders of magnitude lower compared to dense glass. The mechanical behaviours (elastic Gels 2015, 1 2 and brittle) are related to the same kinds of gel characteristics: pore volume, silanol content and pore size. Elastic modulus depends strongly on the volume fraction of pores and on the condensation reaction between silanols. Concerning the brittleness features: rupture modulus and toughness, it is shown that pores size plays an important role. Pores can be considered as flaws in the terms of fracture mechanics and the flaw size is related to the pore size. Weibull's theory is used to show the statistical nature of flaw. Moreover, stress corrosion behaviour is studied as a function of environmental conditions (water and alcoholic atmosphere) and temperature.

Les matériaux poreux : un domaine scientifique et technologique pluridisciplinaire au futur radieux

Matériaux & Techniques, 2015

Les materiaux poreux couvrent un champ scientifique et technologique multidisciplinaire tres larg... more Les materiaux poreux couvrent un champ scientifique et technologique multidisciplinaire tres large. Ils sont mis en œuvre dans de nombreux dispositifs et procedes existants ou emergents, lies a de forts enjeux societaux tant en termes environnementaux qu’economiques. Notre choix a ete d’illustrer les avancees dans le domaine des materiaux poreux au travers de trois exemples specifiques : celui de l’ingenierie des materiaux poreux avec le cas de mesoporeux organiques prepares a partir de polymeres a blocs, celui de l’utilisation de la modelisation et de la simulation numerique avec le cas de l’adsorption d’especes moleculaires a l’echelle nanometrique, et enfin celui des applications technologiques avec le cas des isolants thermiques.

Nanostructuration of cellulose aerogels and their organic-inorganic hybrids

Acknowledgements: research leading to these results was funded within the 7th EU Framework Progra... more Acknowledgements: research leading to these results was funded within the 7th EU Framework Program, (FP7/2007-2013), under grant agreement n°260141, AEROCOINS project, and French National Research Agency (ANR), project “Nanocel” ANR-09-HABISOL-010.

The European Physical Journal Special Topics, 2015

Element optique comprenant un aérogel sans fissure

Procédé de fabrication d'un élément optique comprenant à sa surface des cellules remplies d&#... more Procédé de fabrication d'un élément optique comprenant à sa surface des cellules remplies d'un aérogel qui ne se fissure ni lors de sa fabrication, ni lors d'une étape postérieure d'imprégnation de l'aérogel par un liquide. La présente invention a également pour objet les éléments optiques susceptibles d'être obtenus par ce procédé.

Design and controlled synthesis by dual polymerization of new organic–inorganic hybrid material for photonic devices

RSC Advances, 2014

ABSTRACT Organic-inorganic hybrid material was synthesized by double polymerization processes i.e... more ABSTRACT Organic-inorganic hybrid material was synthesized by double polymerization processes i.e. a sol-gel process and organic polymerization respectively. For this study, hybrid monomer, 4-vinyl ether-phenyltriethoxysilane (VEPTES) was used as starting building block. First, the silica matrix with tunable ratio of siloxane and silanol units was synthesized by a sol-gel process under acidic conditions and the organic network was formed by cationic photopolymerization of vinyl ether groups. Mineral and organic polymerization kinetics were respectively monitored by liquid 29Si-NMR and IR spectroscopy. The effect of the silicate backbone on the organic photopolymerization process was studied and elucidated. The optical performance of this new hybrid material has been studied using the near-infrared spectroscopy.

Gas and liquid permeability in nano composites gels: Comparison of Knudsen and Klinkenberg correction factors

Microporous and Mesoporous Materials, 2014

ABSTRACT We measured gas and water permeability in sets of nano-composite silica gels, (silica ge... more ABSTRACT We measured gas and water permeability in sets of nano-composite silica gels, (silica gel network with aerosil particles), which are highly porous but low permeability materials. Experimental results showed that gas and liquid permeability increased with aerosil content, allowing control of transport properties. Our results also showed that gas permeability was more than one order of magnitude higher than water permeability. This difference was analysed in view of the gas slippage effect. To this end, we tested and compared different correction factor models (Knudsen and Klinkenberg correction factors) proposed in the literature. We showed that the Klinkenberg factor increases with porosity, and discuss the effect of tortuosity. Models that account for porosity and tortuosity improve the accuracy of the prediction. The Knudsen correction increased the accuracy of the experimental data and made it possible to extrapolate the intrinsic permeability from the gas permeability with quite reasonable accuracy.

Aeropectin: Fully Biomass-Based Mechanically Strong and Thermal Superinsulating Aerogel

Biomacromolecules, 2014

Monolithic pectin aerogels, aeropectins, were prepared via dissolution-gelation-coagulation and s... more Monolithic pectin aerogels, aeropectins, were prepared via dissolution-gelation-coagulation and subsequent drying with supercritical CO2. Aeropectin had pore sizes that varied from mesopores to small macropores and compression moduli in the range from 4 to 18 MPa. Aeropectins show plastic deformation up to 60% strain before the pore walls collapse. Pectin aerogels have a thermal conductivity below that of air in ambient conditions, making them new thermal superinsulating fully biomass-based materials. The contribution of gas and solid conduction plus radiative heat transfer were determined and discussed.

Journal of the American College of Cardiology, 1997

Objectives. This survey sought to determine actual practices in the management of acute myocardia... more Objectives. This survey sought to determine actual practices in the management of acute myocardial infarction on a nationwide scale. Background. Few data are available regarding the adoption of clinical trial results of treatment of myocardial infarction into "real-world" clinical practice. Methods. Of 501 intensive care units in France, 373 (74%) collected data from all patients with myocardial infarction admitted within 48 h of symptom onset during November 1995. Results. Data from 2,563 patients (71% men; mean age [؎SD] 67 ؎ 14 years) were included. Time from symptom onset to admission was <6 h in 1,467 patients (62%). Thrombolysis was used in 822 patients (32%) and primary angioplasty in 330 (13%). The use of reperfusion therapy decreased markedly with age. During the first 5 days, heparin was prescribed in 96% of patients, aspirin in 89%, nitrates in 87%, beta-adrenergic blocking agents in 64%, angiotensin-converting enzyme inhibitors in 46% and calcium antagonists in 17%. Coronary angiography was performed in 33% of patients, and 58% had echocardiographic assessment of left ventricular ejection fraction (LVEF). Median LVEF was 50%. The 5-day mortality rate was 7.7% compared with 12.1% in a previous French survey carried out in 1984. By multivariate analysis, independent predictors of mortality were age, anterior infarction, history of stroke and heart failure and, when added to the model, Killip class and LVEF. Conclusions. This survey shows that the results of therapeutic trials have largely translated to clinical practice, resulting in improved early outcome compared with the early 1980s. However, continuous efforts should be made to shorten the time delay before hospital admission and to increase the proportion of elderly patients receiving reperfusion therapy.

Journal of Sol-Gel Science and Technology, 2011

In order to improve the mechanical properties of silica aerogels, we propose the synthesis of nan... more In order to improve the mechanical properties of silica aerogels, we propose the synthesis of nano composite aerogels. Silica particles (20-100 nm) are added in the monomer solution, just before gelling and supercritical drying. The silica particles addition increases the mechanical properties, but also affects the aggregation process, the aerogel structure and the pore sizes. We discuss the different parameters which infer in the mechanical behaviour of silica aerogel such as: brittle behaviour, load bearing fraction of solid (pore volume), internal stresses (shrinkage), size and distribution of flaws, subcritical flaws propagation (chemical susceptibility). With silica particles addition, the mechanical properties rapidly increase, stiffening and strengthening the structure by a factor 4-8. Moreover, the mechanical strength distribution and the Weibull modulus characterizing the statistical nature of flaws size in brittle materials show a more homogeneous strength distribution. The composite structure is made of two imbricate networks, the polymeric silica and the particles silica networks. Ultra Small Angle X-ray Scattering experiments show that besides the fractal network usually built up by the organosiloxane, the silica particles is forming another fractal structure at a higher scale. The fractal structure could be related to the low Weibull parameter characteristic of a large flaws size distribution, pores being the critical flaws. Keywords Aerogels Á Composites Á Mechanical properties Á Weibull modulus Á Fractal 1 Introduction Aerogels have drawn increasing interest in different fields from their use in fundamental physics research to their application as specific materials. Silica aerogels are fascinating materials because of their peculiar physical properties, such as very low sound velocity [1], large specific surface area [2], low thermal conductivity [3], and fractal structure [4, 5]. The current applications of aerogels include their use as catalysts [8], insulators [3], cosmic dust and space debris captors [9] and glass precursors [7, 10]. These peculiar features are essentially due to the very large pore volume, which can be easily tailored from 0 to 99.5%. This pore volume is controlled by the sol-gel synthesis conditions [6] or sintering [7]. Aerogels are generally described as fractal network [4, 5, 11, 12] in the length scale between 1 and 100 nm. This fractal structure is the result of the aggregation of small particles (1-2 nm) and depends on chemical reaction conditions [5-12]. The aerogel network can be described as an assembly of aggregates (*100 nm). The aggregates can T. Woignier (&) IMEP (Institut Méditerranéen d

Nanostructural damage associated with isostatic compression of silica aerogels

Journal of Non-Crystalline Solids, 2004

ABSTRACT Isostatic compression of silica aerogels is known to allow densification of these highly... more ABSTRACT Isostatic compression of silica aerogels is known to allow densification of these highly porous materials. However, at the onset of compression, hydrophobic and consequently slightly reacting aerogels, exhibit a decrease in bulk modulus. This unusual behavior is associated with damage occurring at low pressures which recovers with further density increase. Damage development and healing are analyzed measuring elastic modulus and, for the first time, internal friction as a function of compression. It is proposed that the origin of damage and healing could be associated with the rupture of tenuous links between clusters of dense silica particles at low density levels, and with the creation of new links between the resulting arms and reacting species that are revealed at cluster interface under higher pressure.

Hypertension, 1998

A slightly elevated urinary albumin excretion rate (UAER) is a predictor of atherosclerotic cardi... more A slightly elevated urinary albumin excretion rate (UAER) is a predictor of atherosclerotic cardiovascular disease. The mechanism is unknown, but moderate office blood pressure elevation has been demonstrated as part of a clustering of known atherosclerotic risk factors in subjects with elevated UAER. Because 24-hour ambulatory blood pressure is a superior predictor of hypertensive target organ involvement, we aimed to investigate blood pressure profile in clinically healthy subjects with elevated UAER. Ambulatory blood pressure monitoring was performed with a portable recorder in 27 subjects with an elevated UAER (Ͼ6.6 g/min, overnight urine collection) and 46 normoalbuminuric control subjects. MeanϮSD systolic and diastolic ambulatory blood pressures (24-hour) were significantly higher in subjects with elevated UAER than in normoalbuminuric controls (134Ϯ12 versus 128Ϯ11 mm Hg and 78Ϯ7 versus 75Ϯ6 mm Hg, PϽ0.05), as were systolic and diastolic blood pressure loads [median (range): 42% (6 to 94%) versus 23% (1 to 89%) and 20% (0 to 68%) versus 6% (0 to 62%), PϽ0.05]. The circadian variation of blood pressure was normal in subjects with elevated UAER. However, the increased urinary loss of albumin could not be solely related to the higher blood pressure. In conclusion, apparently healthy subjects with elevated UAER had slightly but significantly higher 24-hour systolic and diastolic blood pressure levels in addition to increased blood pressure loads but normal circadian variation. The demonstrated differences in blood pressure may offer a partial explanation for the association between elevated urinary albumin excretion and atherosclerotic cardiovascular risk.

Development and characterization of ultra-porous silica films made by the sol–gel method. Application to biosensing

Applied Physics A, 2013

ABSTRACT The aim of this work is to demonstrate the sensing ability of reverse-symmetry waveguide... more ABSTRACT The aim of this work is to demonstrate the sensing ability of reverse-symmetry waveguides to investigate adsorption of casein and build-up of poly-L-lysine mediated casein multilayers. A first part of this study is dedicated to the elaboration and characterization of ultra-porous thin films with very low refractive indices by an appropriate sol–gel method. This will form the basis of our planar optical sensors. Optical waveguide light mode spectroscopy is a real-time and sensitive method to study protein adsorption kinetics and lipid bilayers. We used it to test the obtained waveguides for in-situ monitoring of biomolecule adsorption. As a result, significant changes in the incoupling peak position were observed during the layer-by-layer adsorption. Finally, refractive index and thickness of the adsorbed layers were established.

Annals of Emergency Medicine, 1999

Background-Recent randomized trials comparing primary coronary angioplasty and intravenous thromb... more Background-Recent randomized trials comparing primary coronary angioplasty and intravenous thrombolysis at the acute stage of myocardial infarction have shown a limited but definite advantage for primary angioplasty. The aim of this study was to document 1-year outcome in patients receiving either thrombolysis or primary angioplasty for acute myocardial infarction in the "real world." Methods and Results-We used a nationwide prospective registry of all patients admitted for acute myocardial infarction in French intensive care units in November 1995. Of the 721 patients who received reperfusion therapy, 152 were treated with primary angioplasty and 569 received intravenous thrombolysis. The two groups were remarkably similar with respect to all baseline descriptors, except that a higher proportion of patients in the angioplasty group had a history of cerebrovascular accident (10% versus 2%, PϽ0.01). In-hospital outcome was not different in the 2 groups. One-year survival was 85.5% in the angioplasty group and 89.5% in the thrombolysis group (Pϭ0.18). Multivariate analysis showed that older age, anterior location of infarction, female sex, and history of heart failure were related to 1-year mortality. In patients alive on day 5, the use of primary angioplasty and higher Killip class were additional adverse prognostic indicators. Conclusions-The results of this large registry of real-world practice indicate no survival benefit for patients treated with primary angioplasty compared with those who received thrombolytic therapy.

Effect of reperfusion therapy on long-term outcome in patients >70 years of age

The American Journal of Cardiology, 2002

... of age. Nicolas Danchin, MD: Affiliations. Dr. Danchin's address is: Département de Cardi... more ... of age. Nicolas Danchin, MD: Affiliations. Dr. Danchin's address is: Département de Cardiologie, Hôpital Européen Georges Pompidou, 20 rue Leblanc, 75015 Paris, France. ... France. ,; Thibaud Demicheli, MD: Affiliations. Cardiologie ...

Epidemiology of myocardial infarction in France: Therapeutic and prognostic implications of heart failure during the acute phase

American Heart Journal, 1999

A national epidemiological study undertaken in November 1995 recensed the data of 2563 patients a... more A national epidemiological study undertaken in November 1995 recensed the data of 2563 patients admitted to 373 Intensive Care Units for acute myocardial infarction. There were 1827 men and 736 women with an average age of 67 years. Seventeen per cent of patients had left ventricular ejection fration (LVEF) < or = 35%. The mortality rate at 5 days was 7.7%. Clinical heart failure (Killip > 1) was observed in 34.4% of patients. 63% of patients were admitted before the 6th hour. Forty-six per cent of patients underwent early revascularisation by thrombolysis and/or angioplasty. The most widely used drugs in the first 5 days were heparin (96%), aspirin (89%), betablockers (65%), and angiotension converting enzyme inhibitors (46%). The influence of region on the demographical features, morbidity, mortality and therapeutic practice was studied. France was divided into 6 regions. In the Centre, the patients were older, with increased morbidity and mortality compared with the national average. Patients in the North East were similar and had a higher incidence of obesity. In the Ile de France, patients were generally younger with a higher incidence of tobacco consumption and their infarcts were generally less severe. Finally, in the South East, the mortality was particularly low. In multivariate analysis living in this region was good prognostic factor whereas low LVEF (< or = 35%) and age > or = 65 years were poor prognostic factors. This study, for the first time in France, describes the clinical features of myocardial infarction admitted to the Intensive Care Unit with respect to criteria of severity (LVEF, Killip) and region of origin of the patients. Its confirms large regional variations in the severity of acute myocardial infarction.