Maîtrise foncière, pratiques agricoles durables et protection de la ressource en eau : quels outils d’intervention sur les AAC ?

Enjeu de santé publique et de préservation des milieux, la protection des captages et de la ressource en eau fait l’objet d’une série de dispositifs mis en oeuvre à la fois de façon règlementaire et volontaire. Les acteurs de la protection, à l’échelon local, ont notamment recours à toute la gamme d’outils fonciers : de la maîtrise de l’usage du sol à l’acquisition foncière en propriété. En plus, la mise en oeuvre de pratiques agricoles durables, par le biais du bail environnemental notamment, est une orientation forte pour concilier activité agricole et protection des ressources en eau. Les expériences observables en Île-de-France font état des obstacles rencontrés pour la mise en oeuvre de ce type d’actions. La principale difficulté, en dehors de la capacité des gestionnaires, concerne le rapport entre la profession agricole et l’instrument foncier. En Île-de-France, la situation est exacerbée compte tenu du contexte de pression foncière forte

Numerical analysis of heat transfer increase in a tube with alternate successive gradual wall deformations

Paper presented to the 10th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Florida, 14-16 July 2014.From previous studies, it is known that the use of wall deformations in alternate directions while keeping a quasiconstant cross-section is an efficient way to enhance the heat transfer in a laminar flow regime inside a tube. In the present study, the tube cross-section shape gradually changes along the tube length while keeping the same cross-sectional area to prevent flow separation areas thereby limiting pressure drops. These wall deformations create vortical macrostructures inside the flow that significantly modify the transfer properties. Two geometrical parameters characterize the tube wall shape: the radial deformation amplitude and its streamwise wavelength. Through a numerical study, the effects of the variation of these two parameters on the flow and on the heat transfer have been studied. An important finding is that the ratio between the wavelength and the amplitude has a significant impact on the observed results: both the friction and the heat transfer increases as this deformation ratio decreases. At the same time, a local analysis of the flow mechanisms has been performed to outline the modifications that occur in the flow pattern when the wall deformations are increased. Flow in the entrance region has also been specifically considered: it has been found that geometrical parameters do have an influence on the length needed for the flow to get fully hydrodynamically and thermally established. Finally a performance analysis has been conducted to assess, for a given performance criterion, the deformation parameters that give optimal results. Through this parametric study, for the given Reynolds and Prandtl numbers, an alternate wall deformed tube geometry that maximizes the heat transfer without significantly increasing the pressure drops can thus be defined.dc201

Statistička analiza nanokapsuliranja niskomolekularnog heparina

The objective of this study was to use Box-Behnken design (BBD) to investigate the influence of formulation variables on the properties of heparin-loaded poly(lactic-co-glycolic acid) (PLGA)-Eudragit-RLPO (E-RLPO) nanoparticles (NP) in terms of mean diameter (as size) and drug encapsulation efficiency. The NPs were prepared by the double emulsion solvent evaporation method. The independent variables were: X1 olymer mass ratio (PLGA:E-RLPO) in the oil phase, X2 concentration of polyvinyl alcohol (PVA) as emulsion stabilizer, and X3 volume of the external aqueous phase (W2). Particle size (analyzed by dynamic light scattering) and encapsulation efficiency (EE, estimated by spectrophotometry) were the investigated responses. The polynomial equation obtained from regression analysis of the reduced model (p = 0.0002, F = 25.7952 and R2 = 0.96) provided an excellent fit. The optimal size for the NP was found to be 134.2 ± 16.5 nm with formulation variables of 48.2:61.8, 0.321 (%, m/V) and 263 mL for X1, X2 and X3, respectively. Probably, due to electrostatic interaction between the negatively charged drug and the positively charged E-RLPO, the percent EE of heparin was between 74.4 ± 6.5 % (lowest value) and 92.1 ± 5.3 % (highest value). The data suggest that BBD is a useful tool in rational design of heparin-loaded NPs.Box-Behnkenovo dizajniranje (BBD) primijenjeno je za praćenje utjecaja formulacijskih varijabli na svojstva nanočestica (NP) s heparinom. Za izradu nanočestica korišten je kopolimer mliječne i glikolne kiseline (PLGA) i Eudragit-RLPO (E-RLPO). Nanočestice su pripravljene metodom dvostruke evaporacije otapala iz emulzije. Nezavisne varijable bile su: X1 omjer masa polimera (PLGA : E-RLPO) u uljnoj fazi, X2 koncentracija polivinil alkohola (PVA) kao stabilizatora emulzije i X3 volumen vanjske vodene faze (W2). Zavisne varijable bile su veličina čestica (analizirana pomoću dinamičkog rasapa svjetlosti) i učinkovitost inkapsuliranja (EE) (praćena spektrofotometrijski). Polinomska jednadžba dobivena regresijskom analizom reduciranog modela odlično je odgovarala (p = 0,0002, F = 25,7952 i R2 = 0,96). Optimalna veličina nanočestica bila je 134,2 ± 16,5 nm s formulacijskim varijablama 48,2:61,8, 0,321 (%, m/V) i 263 mL for X1, X2 odnosno X3. Vjerojatno je zbog elektrostatskih interakcija između negativno nabijene ljekovite tvari i pozitivno nabijenog E-RLPO učinkovitost inkapsuliranja heparina varirala od 74,4 ± 6,5 % (najniža vrijednost) do 92,1 ± 5,3 % (najviša vrijednost). Rezultati sugeriraju da je BBD vrlo korisno u racionalnom dizajniranju nanočestica s heparinom

Preparation and in vivo evaluation of insulin-loaded biodegradable nanoparticles prepared from diblock copolymers of PLGA and PEG

YesThe aim of this study was to design a controlled release vehicle for insulin to preserve its stability and biological activity during fabrication and release. A modified, double emulsion, solvent evaporation, technique using homogenisation force optimised entrapment efficiency of insulin into biodegradable nanoparticles (NP) prepared from poly (dl-lactic-co-glycolic acid) (PLGA) and its PEGylated diblock copolymers. Formulation parameters (type of polymer and its concentration, stabiliser concentration and volume of internal aqueous phase) and physicochemical characteristics (size, zeta potential, encapsulation efficiency, in vitro release profiles and in vitro stability) were investigated. In vivo insulin sensitivity was tested by diet-induced type II diabetic mice. Bioactivity of insulin was studied using Swiss TO mice with streptozotocin-induced type I diabetic profile. Insulin-loaded NP were spherical and negatively charged with an average diameter of 200–400 nm. Insulin encapsulation efficiency increased significantly with increasing ratio of co-polymeric PEG. The internal aqueous phase volume had a significant impact on encapsulation efficiency, initial burst release and NP size. Optimised insulin NP formulated from 10% PEG–PLGA retained insulin integrity in vitro, insulin sensitivity in vivo and induced a sustained hypoglycaemic effect from 3 h to 6 days in type I diabetic mice

Preparation and Characterization of a Lovastatin-Loaded Protein-Free Nanostructured Lipid Carrier Resembling High-Density Lipoprotein and Evaluation of its Targeting to Foam Cells

This study was designed to investigate whether a non-protein nanostructured lipid carrier (NLC) resembling high-density lipoprotein (HDL) could deliver a hydrophobic anti-atherogenic drug, lovastatin, to foam cells. Lovastatin-loaded NLC (LT-NLC) was prepared by a nanoprecipitation/solvent diffusion method. The LT-NLC-apoprotein (LT-NLC-apo) was prepared by incubating LT-NLC with native HDL. The physicochemical parameters of LT-NLC were characterized in terms of particle size, zeta potential, morphology, entrapment efficiency, and crystallization behavior. Targeting behavior and mechanism were demonstrated by the incubation of LT-NLC-apo with a RAW 264.7 macrophage-derived foam cell model in the presence or absence of very-low-density lipoprotein (VLDL) and lipase. The results showed that LT-NLC was solid spherical or oval in shape with an average diameter of 13.8 ± 2.2 nm, zeta potential of −29.3 ± 0.2 mV and entrapment efficiency of 96.2 ± 1.3%. Phagocytosis studies showed that uptake of LT-NLC-apo by macrophages was significantly lower than LT-NLC (p < 0.01), suggesting that LT-NLC-apo could possibly escape recognition from macrophages in vivo. The uptake was increased twofold when LT-NLC-apo was incubated with transfected foam cells containing VLDL and lipase. These results indicated that non-protein NLC resembling HDL could be a useful tool to deliver lipophilic anti-atherogenic drugs to foam cells, and that uptake could be enhanced by the VLDL receptor pathway

Development and validation of an HPLC method for the determination of fluorouracil in polymeric nanoparticles

The objective of this work was to develop and validate a rapid high performance liquid chromatography (HPLC) method for the quantitative analysis of fluorouracil (5-FU) in polymeric nanoparticles. Chromatographic analyses were performed on an RP C18 column with a mobile phase consisting of acetonitrile and water (10:90, v/v) at a flow rate of 1 mL/min. The 5-FU was detected and quantitated using a photodiode array detector at a wavelength of 265 nm. The method was shown to be specific and linear in the range of 0.1-10 µg/mL (r = 0.9997). The precision (intra- and inter-day) was demonstrated because the maximum relative standard deviation was 3.51%. The method is robust relative to changes in flow rate, column and temperature. The limits of detection and quantitation were 10.86 and 32.78 ng/mL, respectively. The method fulfilled the requirements for reliability and feasibility for application to the quantitative analysis of 5-FU in polymeric nanoparticles.O objetivo deste trabalho foi desenvolver e validar um método rápido de cromatografia líquida de alta eficiência (CLAE) para análise quantitativa de fluorouracila (5-FU) em nanopartículas poliméricas. Corridas cromatográficas foram realizadas sob uma coluna RP C18 com uma fase móvel consistindo de acetonitrila e água (10:90, v/v) a um fluxo de 1 mL/min. O 5-FU foi detectado e quantificado através de um detector de fotodiodos em um comprimento de onda de 265 nm. O método demonstrou ser específico e linear na faixa de 0,1-10 µg/mL (r =0.9997). As precisões (intra e inter dia) revelaram um desvio padrão relativo máximo de 3,51%. O método é robusto considerando mudanças realizadas no fluxo da fase móvel, temperatura e marca da coluna. Os limites de detecção e quantificação foram de 10,86 e 32,78 ng/mL, respectivamente. O método cumpriu os requisitos para ser considerado confiável e viável para aplicação na análise quantitativa de 5-FU em nanopartículas poliméricas

Application of polymeric nanoparticles in food sector

Nanotechnology presents opportunities to create new and better products. Nano technology has huge impact in many applications including food industry. Product of nanotechnology, such as polymeric nanoparticle, can be utilized to improve food quality by extending food shelf life, increase food safety, lower the cost and enhance the nutritional benefits. This chapter provides an overview of the properties of polymeric nanoparticle, preparation techniques, as well as the role polymeric nano-particles in the food industr

Clonage de l'ADNc de la Carboxyl Ester Lipase humaine: expression tissulaire et cartographie chromosomique

SIGLEAvailable from INIST (FR), Document Supply Service, under shelf-number : T 84754 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc

Influence des déformations successives alternées de la paroi sur l'accroissement des performances d'échange d'un tube : application aux échangeurs multifonctionnels

The work presented here is focused on the numerical study of specific successive wall deformations in alternate directions, applied to a tubular geometry. Those deformations help modifying the flow structure and thus its heat transfer and mixing properties. One of the main aims of the study is to apply those deformations to multifunctional exchangers which are heat exchangers and chemical reactors at the same time. The study is mainly focused on laminar flows and all the numerical calculations were performed using the CFD code ANSYS Fluent. The first step of the study is to assess the secondary flow created by the wall deformations. The influence of several deformation geometrical parameters has also been studied. In order to enhance the mixing in the deformed tube, the wall deformations have been applied to coaxial configurations (often used in the industry). Two kinds of annular configurations have been evaluated. At first, the wall deformations are applied to the external and internal walls of the coaxial tube. The effect on the heat transfer enhancement of the longitudinal and angular phase-shifting between the two deformations has been specifically assessed. The second configuration considered combines the alternate deformations on its external walls and a swirled internal wall. This particular annular configuration creates chaotic advection in laminar flows, therefore helping increasing the mixing. This geometry is used as a solar captor and helps increasing the global performances when compared with a smooth tube usually used. The last part of the presented work is focused on the experimental validation of the numerical results. Techniques such as PIV and LDA are used to measure local velocity fields in a plane duct with alternate deformations applied to its lower wall.Les travaux de thèse sont consacrés à l’étude numérique de l’application de macro-déformations successives alternées a la paroi d’un tube. La modification de l’écoulement du fait des déformations permet de modifier ses propriétés en termes de transfert thermique et de mélange. L’objectif de l’étude d’un tel dispositif est entre autre de l’appliquer pour des configurations d’échangeurs multifonctionnels, qui sont à la fois échangeurs de chaleur et réacteurs chimiques. L’étude s’intéresse principalement aux écoulements laminaires. Les calculs sont réalisés avec le code ANSYS Fluent. L’étude est tout d’abord consacrée à la caractérisation de l’écoulement secondaire créé par les déformations ainsi qu’à l’influence des différents paramètres de déformation. Afin d’améliorer le mélange dans l’écoulement, l’étude d’une configuration coaxiale déformée a été envisagée (cette géométrie correspond de plus à une configuration d’écoulement utilisée dans l’industrie). Deux configurations annulaires ont été considérées. Dans un premier temps, les déformations pariétales ont été appliquées aux tubes interne et externe : différents déphasages longitudinaux et angulaires entre ces deux déformations ont été étudiés pour optimiser les performances thermo-hydrauliques. La seconde configuration combine des déformations sur la paroi externe et un swirl sur la paroi interne de la géométrie. Cette configuration particulière permet en régime laminaire d’augmenter significativement le mélange du fait de l’apparition d’advection chaotique dans l’écoulement. Cette dernière géométrie est appliquée dans le cas d’un échangeur solaire à concentration et permet d’améliorer les performances par rapport à un tube lisse dans des conditions similaires. La dernière partie de l’étude est consacrée à une validation expérimentale des résultats numériques lorsque les déformations sont appliquées à une plaque. Des mesures par PIV et LDA ont été réalisées pour mesurer la vitesse locale de l’écoulement