A922 Sequential measurement of 1 hour creatinine clearance (1-CRCL) in critically ill patients at risk of acute kidney injury (AKI)

Meeting abstrac

Use of hydrogen bonded layer-by-layer assemblies for particle manipulation

International audienceWith the constant progress in miniaturization of systems and devices, the manipulation of µ-objects is becoming increasingly important. Chemical functionalization is a promising way to improve this manipulation, in particular multilayer polymer films based on hydrogen bonds can allow to achieve reversible adhesion of µ-objects. To prepare such hydrogen-bonded Layer-by-Layer (LbL) films, poly(ethylene glycol) (PEG), poly(acrylic acid) (PAA), Tannic acid (TA) and Poly(N-isopropylacrylamide) carboxylic acid-terminated (PNIPAM) were selected due to their hydrogen donor or acceptor properties. The growth of these films was originally confirmed by in situ optical reflectometry. Their erasability was also investigated by exposure to an aqueous solution with a pH gradient. Depending on the polymer couple, the pH of disintegration was adjusted from an acidic to a basic medium. The surface roughness was also affected by the building block of the LbL architecture since a rougher surface was recorded for PEG/TA than for PEG/PAA. To mimic the manipulation of an object, adsorption and desorption of a model object (silica particles) was carried out onto a LbL film. Two approaches were employed: optical reflectometry as an indirect method and optical microscopy for direct visualization. For both analyses, particles of different sizes could be adsorbed onto a PEG/PAA or PAA/PNIPAM film. Finally, a complete desorption of the particles was recorded due to the disintegration of the LbL film when the pH was increased

Predictive tools for selection of appropriate polyelectrolyte multilayer film for the functionalization of organic membranes

International audienceLayer-by-layer adsorption of oppositely charged polyelectrolytes is a suitable method to improve the filtration properties of polyethersulfone (PES) membrane. Therefore, a weak polycation (poly(allylamine hydrochloride, PAH) was combined with either a weak polyanion (polyacrylic acid, PAA) or a strong polyanion (polystyrene sulfonate, PSS) to create a polyelectrolyte multilayer film (PEM) of 11 layers. Adsorption of the polyelectrolytes was performed using saline solutions at native pH or pH 6. The growth of (PAH-PAA)n or (PAH-PSS)n multilayer film was monitored in situ by optical reflectometry (OR) and quartz crystal microbalance (QCM-D). At the end of the build-up, a rinsing step at pH 2 was done to test the stability of the film at the filtration conditions. The rinsing step did not lead to desorption of the (PAH-PSS)n multilayer. On the contrary, films made of PAH and PAA were strongly affected, but did not entirely disassemble by changing the pH. Filtration efficiency of PEM-modified membrane was finally investigated by filtrating copper ions solution. These membranes were alternately immersed into polyelectrolyte solutions during 10 min to achieve the functionalization. As predicted by the OR and QCM-D results, a good retention of copper cations was recorded for (PAH-PAA)n modified membrane. On the contrary, a poor retention was observed for membrane modified by (PAH-PSS)n multilayer despite their good behavior during the filtration step. This could be attributed to a different wall pores modification

Application of original assemblies of polyelectrolytes, urease and electrodeposited polyaniline as sensitive films of potentiometric urea biosensors

Original assemblies were prepared for use as sensitive films of potentiometric enzyme urea sensors, and compared to identify the more efficient structure with respect to stability. These films included electrodeposited polyaniline, used as transducer, urease, used as catalyst, and biocompatible polyelectrolytes, used as a matrix to preserve the integrity of the enzyme in the sensitive film. Two kinds of assemblies were done: the first one consisted in the adsorption of urease onto a polyaniline film followed by the adsorption of a chitosan-carboxymethylpullulan multilayer film, while the second one consisted in the adsorption of a urease-chitosan multilayer film onto an electrodeposited polyaniline film. The morphological features and growth of these assemblies were characterized by scanning electron microscopy and quartz crystal microbalance, respectively. This allowed us to demonstrate that the assemblies are successfully formed onto the electrodes of the sensors. The potentiometric responses of both assemblies were then measured as a function of urea concentration using a home-made portable potentiostat. The electrochemical response of resulting sensors was fast and sensitive for both types of assemblies, but the stability in time was much better for the films obtained from alternative adsorption of urease and chitosan onto a layer of urease adsorbed over electrodeposited polyaniline

Pediatr Obes

BACKGROUND: The nine French regional health networks for the prevention and care of paediatric obesity offer a 2-year program of multidisciplinary primary care (medical, dietetical, psychological, adapted physical activity) based on multicomponent lifestyle interventions. OBJECTIVES: To assess the short-term and long-term impact of care management. METHODS: The impact of the multidisciplinary care was assessed by changes in the body mass index (BMI) Z score during the period of the care, and at least 2 years after the end. Anthropometric data were collected at baseline and at the end of the care either through a digital medical file or through direct phone contacts with the referring. Long-term outcomes were assessed through studies relative to post follow-up evaluation. RESULTS: At the end of the period of the care in a network, 72.9% of 6947 children had decreased their BMI Z score from 3.6 +/- 1.0 DS at baseline to 3.3 +/- 1.1 DS at the end. The four studies relative to long-term evaluation showed a pursuit of the decrease of BMI Z score during the 5.1 years after the beginning of the care. CONCLUSIONS: The care provided by regional French networks for prevention and care of paediatric obesity induce a reduction of BMI that continues afterwards