Apport du volume placentaire par échographie 3D au premier trimestre de grossesse dans le dépistage des pathologies vasculaires placentaires et des retards de croissance

DIJON-BU Médecine Pharmacie (212312103) / SudocSudocFranceF

Elaboration de films polyelectrolytes a base de polysaccharides amphiphiles : application à l immobilisation de composés hydrophobes d intérêt biologique

Dans le but d immobiliser des composés hydrophobes présentant un intérêt biologique à l interface solide/liquuide, des fims minces à base de polysaccharides amphiphiles et de divers polycations ont été élaborés par la technique d auto-assemblage couche par couche (lbl). Cette technique consiste à adsorber successivement sur un support chargé des couches de polycations et de polyanions. Les polysaccharides utilisés sont des carboxyméthylpululanes (CMP) porteurs de chaînons alkyle (CMP- Cn). L influence des caractéristiques moléculaires eet macromoléculaires de ces dérivés (leur hydrophobie, leur masse molaire, etc) sur les caractéristiques des films réalisés a été systématiquement étudiée. Il a été notamment montré qu il était possible de moduler l incrément d épaisseur ainsi que la microstructure des films polyélectrolytes en jouant sur le caractère plus ou moins hydrophobe des polysaccharides amphiphiles. Des corrélations ont été établies entre les propriétés des polysaccharides amphiphiles en solution et les caractéristiques des films obtenus. Il a été montré que les nanodomaines hydrophobes intra et/ou intermoléculaires formés en solution aqueuse étaient préservés lors du processus d auto-assemblage. Ces nanodomaines ont été utilisés comme nano-réservoirs pour le piégeage de colorants hydrophobes. Il a été montré que la capacité de piégeage des films pouvait être modulée en fonction du caractère plus ou moins hydrophobes des carboxyméthylpullulanes alkylés. Enfin, un peptide hydrophobe ionophore, la gramicidine A, a été incorporé avec succès dans ces assemblages polyélectrolytes dans le but de préparer des films antibactériens. L activité de ces derniers a été vérifiée auprès d une bactérie Gram+, Enterococcus Faecalis.The goal of the project was to immobilize hydrophobic drugs or "biomolecules" in thin films containing amphiphilic polysaccharides. The films were obtained using the Layer-by-layer technique (LbL). This technique consists of sequential adsorption of polycations and polyanions onto a charged substrate. The modified polysaccharides used in this study are obtained by grafting alkyl chains on carboxyméthylpullulan (CMP) precursor. The influence of the polyelectrolytes characteristics used on the films growth was systematically studied. We showed that it was possible to modulate the thickness as well as the multilayers films microstructure by changing the characteristics of the amphiphilic polysaccharides used. Moreover the properties of amphiphilic polysaccharides in solution and at solid/liquid interfaces are similar. Furthermore the intra and/or intermolecular hydrophobic nanodomains are preserved during adsorption process. These hydrophobic nanodomains showed their potential as nanocontainers for actives molecules or dyes. Moreover the sequestration efficiency of the films can be modulated as a function of the hydrophobicity of the alkylated CMP. Lastly, an hydrophobic ionophore antibacterial polypeptide "gramicidin A" was trapped in these nanocontainers and its antibacterial activity against Enterococcus faecalis was tested. our results clearly show that this technique of incorporation of an active species within multilayers film allow us to obtain an antibacterial surface by a simple way.ROUEN-BU Sciences (764512102) / SudocSudocFranceF

Undocumented : The Architecture of Migrant Detention

"Architectural practice requires the integration of often complex technical construction requirements with an equal measure of empathy for the occupants of the spaces we envision. In the deceptively simple pen-and-ink drawings and tiny photographs presented in this book we find technical information and human empathy in tension, an inevitable outcome wherever architecture is called upon to oppress living beings. This slim book does not only contain more detail of the architecture of detention centres than some academic works on the architecture of incarceration, but it begins to outline the invisible experience of hidden-away people in hidden-away places." -- P. [4] of cover

Loading and release of small hydrophobic molecules in multilayer films based on amphiphilic polysaccharides

We report on the loading and release behaviors of polyelectrolyte multilayers based on hydrophobically modified carboxymethylpullulan (CMP) derivatives and poly(ethyleneimine) (PEI) toward hydrophobic dye. The dye-loaded films are obtained according to two different protocols: (i) the postdiffusion approach, which involves the diffusion of the dye within preassembled self-assemblies, and (ii) the precomplexation method. which requires the formation of a water-soluble amphiphilic CMP derivative-dye complex before the multilayer buildup. In both cases, we provide clear evidence for the entrapment of the dye in hydrophobic nanoreservoirs resulting from the aggregation of decyl pendent groups grafted on CMP chains. We show that the loading capacity of the multilayers, as well as their release behavior, can be tuned by varying the grafting degree of CMP chains. Moreover, we demonstrate the possibility to trigger the subsequent release of the loaded dye molecules by varying the composition of the surrounding solution

Preparation and characterization of azlactone functionalized polymer supports and their application as scavengers

International audienc

Incorporation of a Hydrophobic Antibacterial Peptide into Amphiphilic Polyelectrolyte Multilayers: A Bioinspired Approach to Prepare Biocidal Thin Coatings

International audienc

A mechanical model for stress development in PA12 tube extrusion

Direct link: http://www.polymer-process.com/directlink.asp?IPP2028International audienceIn poly amide 12 tube extrusion, calibration is the key step of the process that affects the subsequent mechanical properties. In previous work it has been shown that according to the calibration conditions, a very oriented skin layer may be created, which has been correlated to an important decrease of elongation at break. In the present paper we develop a thermomechanical model which consists of two parts: a viscoelastic mechanical model for the calculation of stresses and a thermal model for the determination of the temperature field. Three types of inputs are necessary: processing parameters, material data (e. g., crystallization kinetics and rheology in the melt, the solid state and the transition zone) and heat transfer coefficients to describe the heat exchanges along the extrusion line. The model allows us to propose a physical interpretation of the oriented layer. During cooling high axial stresses are frozen in the first solidified layers. They induce a plastic deformation of the polymer leading to a high level of orientation in the outer zones