Influence of citric acid and water on thermoplastic wheat flour/poly(lactic acid) blends. I: Thermal, mechanical and morphological properties

Wheat flour was plasticized with glycerol and compounded with poly(lactic acid) in a one-step twin-screw extrusion process in the presence of citric acid with or without extra water. The influence of these additives on process parameters and thermal, mechanical and morphological properties of injected samples from the prepared blends, was then studied. Citric acid acted as a compatibilizer by promoting depolymerization of both starch and PLA. For an extrusion without extra water, the amount of citric acid (2 parts for 75 parts of flour, 25 parts of PLA and 15 parts of glycerol) has to be limited to avoid mechanical properties degradation. Water, added during the extrusion, improved the whole process, minimizing PLA depolymerization, favoring starch plasticization by citric acid and thus improving phases repartition

Influence of citric acid on thermoplastic wheat flour/poly (lactic acid) blends. II. Barrier properties and water vapor sorption isotherms

The effects of citric acid on wheat flour/glycerol/poly(lactic) acid (PLA) blends prepared by one-step twin-screw extrusion have been studied to improve barrier properties of starch based materials. A series of injected samples were produced from prepared compounds with varying ratio (0-20 part) of citric acid. The effects of citric acid on the water vapor permeability, oxygen permeability and water solubility in the film were then investigated. The barrier properties results proved that citric acid behaves as compatibilizing agent between starch and PLA phases for ratios between 0 and 10 parts. When the added amount exceeds 10 parts, CA acted as a plasticizer and/or promoted the hydrolysis of the starch glycosidic bonds

Cystamine/cysteamine rescues the dopaminergic system and shows neurorestorative properties in an animal model of Parkinson's disease.

The neuroprotective properties of cystamine identified in pre-clinical studies have fast-tracked this compound to clinical trials in Huntington's disease, showing tolerability and benefits on motor symptoms. We tested whether cystamine could have such properties in a Parkinson's disease murine model and now provide evidence that it can not only prevent the neurodegenerative process but also can reverse motor impairments created by a 6-hydroxydopamine lesion 3weeks post-surgery. Importantly, we report that cystamine has neurorestorative properties 5weeks post-lesion as seen on the number of nigral dopaminergic neurons which is comparable with treatments of cysteamine, the reduced form of cystamine used in the clinic, as well as rasagiline, increasingly prescribed in early parkinsonism. All three compounds induced neurite arborization of the remaining dopaminergic cells which was further confirmed in ex vivo dopaminergic explants derived from Pitx3-GFP mice. The disease-modifying effects displayed by cystamine/cysteamine would encourage clinical testing

Travail vécu et travail perçu : quels sont les conséquences du passage à l’AB pour les éleveurs laitiers ?

National audienceUne offre qui stagne, seulement 4% de la SAU convertie en AB Une demande qui augmente avec +10,8% entre 2009 et 2010 Cet écart nécessite de se questionner sur : -Quels sont les freins au développement de l’agriculture biologique au niveau des exploitations ? -Pour l’élevage laitier, où le poids de l'astreinte pèse énormément, quelles sont les conséquences du passage à l’agriculture biologique sur les conditions de travail

Conversion to organic farming and consequences on work organisation and work perception

International audienceAvec environ 3% de sa SAU conduit en agriculture biologique (AB), la France n’atteindra pas les objectifs qu’elle s’était fixée de 6% en 2012. Le surplus de travail (réel ou supposé) lié au mode de production biologique semble constituer un frein à la conversion, à l’heure où les agriculteurs cherchent plutôt à réduire leur charge de travail. Il apparait donc nécessaire, pour qui s’intéresse à la pérennité et la transmissibilité des exploitations biologiques, de se poser la question des conditions de travail. Afin d’identifier les changements survenus durant la transition vers l’AB, leurs conséquences sur l’organisation du travail, et la perception qu’ont les agriculteurs de leur travail, 18 enquêtes ont été réalisées dans la région Rhône-Alpes auprès d’éleveurs laitiers et de céréaliers convertis à l’AB depuis une dizaine d’années. A cette période de transition correspondent une succession de changements importants, qui varient selon les contextes techniques et socio-économiques et les caractéristiques des systèmes de production. Ces changements sont aussi conditionnés par les projets et les attentes des agriculteurs, qui évoluent durant la période de transition. Dans l’ensemble les agriculteurs acceptent bien la plupart des changements liés à l’AB, et tirent même souvent parti de la conversion pour résoudre des problèmes de travail, par le recours au salariat, ou la recherche d’associés, par exemple. Afin d’encourager et d’accompagner les conversions à l’AB, les évolutions de l’organisation du travail doivent certes être mieux anticipées, mais il est tout aussi important d’avoir conscience du fait que passer en bio fait aussi évoluer la perception qu’ont les agriculteurs de leur travail. / With organic farming accounting for only 3% of the national agricultural surface area, France will not reach its conversion objective of 6% in 2012. Work surplus (real or supposed) seems to act as a hindrance to conversion as French farmers often seek to reduce their workloads. Thinking about the reproducibility or transmission of organic farming systems has to take into account work conditions on organic farms. In order to identify changes occurring during the transition to organic farming and to understand their consequences on work organisation and on farmers' perception of work, 18 surveys were conducted in the Rhône-Alpes region on dairy farms and cereal farms having converted to organic farming approximately ten years ago. Successive changes in work organisation are important throughout the transition period. Such changes vary according to technical and socio-economic backgrounds, production and processing system organisation. They are also conditioned by farmers' projects and expectations, which evolve during the transition period. Farmers tend to readily accept most of the changes and often take advantage of conversion to solve work problems, by hiring labourers or looking for partners, for instance. In order to encourage conversion to organic farming, modifications to work organisation need to be anticipated while it is also important to keep in mind that going organic may change farmers' perceptions of their work

Light beating spectroscopy measurements of micelles mutual diffusion coefficient within oil in water microemulsions in the presence of sodium chloride

Using light beating spectroscopy we have measured the mutual diffusion coefficient of micelles within oil in water microemulsions in the presence of added NaCl. The experimental results have been explained by replacing the viscosity of the continuous phase, which appears in the diffusion coefficient of systems of interacting particles, by the viscosity of the microemulsion. They lead to a positive second virial coefficient linked with the electric charge of the micelles and, for the highest NaCl concentrations, to a micellar radius which is close to the radius deduced from osmotic pressure.On a mesuré par la technique des battements lumineux, le coefficient de diffusion mutuel des micelles de microémulsions d'huile dans l'eau en présence de NaCl. Les résultats expérimentaux ont été interprétés en remplaçant dans l'expression du coefficient de diffusion d'assemblées de particules en interaction, la viscosité de la phase continue par la viscosité de la microémulsion ellemême. Ils conduisent à une valeur positive du second coefficient du viriel liée à la charge électrique des micelles, et pour les plus fortes concentrations en NaCl, à un rayon micellaire voisin de celui déduit de mesures de pression osmotique

Light beating spectroscopy measurements of microemulsion diffusion coefficient

The translational diffusion coefficient of microemulsions formed from water, toluol, sodium dodecyl-sulfate and alcohol, has been measured using light beating spectroscopy. The experimental results show that the microemulsions are monodisperse, the micelles being electrically charged.On a mesuré par la méthode des battements lumineux le coefficient de diffusion de micelles formées au sein de mélanges quaternaires eau-alcool-tensioactif-toluène, pour différentes valeurs de la fraction volumique de la phase dispersée. Les résultats obtenus conduisent d'une part à admettre une monodispersion du diamètre des micelles, d'autre part à un bon accord — expliqué théoriquement - avec les mesures de turbidité

Survival of a novel subset of midbrain dopaminergic neurons projecting to the lateral septum is dependent on NeuroD proteins

Midbrain dopaminergic neurons are highly heterogeneous. They differ in their connectivity and firing patterns and, therefore, in their functional properties. The molecular underpinnings of this heterogeneity are largely unknown, and there is a paucity of markers that distinguish these functional subsets. In this paper, we report the identification and characterization of a novel subset of midbrain dopaminergic neurons located in the ventral tegmental area that expresses the basic helix-loop-helix transcription factor, Neurogenic Differentiation Factor-6 (NEUROD6). Retrograde fluorogold tracing experiments demonstrate that Neurod6(+) midbrain dopaminergic neurons neurons project to two distinct septal regions: the dorsal and intermediate region of the lateral septum. Loss-of-function studies in mice demonstrate that Neurod6 and the closely related family member Neurod1 are both specifically required for the survival of this lateral-septum projecting neuronal subset during development. Our findings underscore the complex organization of midbrain dopaminergic neurons and provide an entry point for future studies of the functions of the Neurod6(+) subset of midbrain dopaminergic neurons. SIGNIFICANCE STATEMENT Midbrain dopaminergic neurons regulate diverse brain functions, including voluntary movement and cognitive and emotive behaviors. These neurons are heterogeneous, and distinct subsets are thought to regulate different behaviors. However, we currently lack the means to identify and modify gene function in specific subsets of midbrain dopaminergic neurons. In this study, we identify the transcription factor NEUROD6 as a specific marker for a novel subset of midbrain dopaminergic neurons in the ventral midbrain that project to the lateral septum, and we reveal essential roles for Neurod1 and Neurod6 in the survival of these neurons during development. Our findings highlight the molecular and anatomical heterogeneity of midbrain dopaminergic neurons and contribute to a better understanding of this functionally complex group of neurons

Twin-Screw Extrusion: a key technology for the biorefinery

International audienceFor more than 30 years, the Laboratory of Agro-industrial Chemistry (LCA) develops an ambitious and multi-scale research topic on the use of twin-screw extrusion (TSE) for the processing of biomass for non-food applications. This chapter will give an overview of past and present projects, discussing specific operating conditions and their consequences on biopolymer native organization. For the production of agro-materials, compounding processes have been designed and in some cases industrialized integrating specific targeted actions such as the plasticization of primary cell-walls (sugar beet, tobacco), the "fusion" of storage polymers (starch, oilseed proteins) and/or the destructuring of secondary cell-walls (lignocellulosic fibers). For the pretreatment of lignocellulosic fibers, the conjugated use of chemicals is also discussed. Those processes have also been coupled with biodegradable polyester blending (involving compatibilization with acid citric) and compounding. In integrated biorefining processes, TSE may also be used simultaneously as a continuous liquid-solid extractor through mechanical pressing or solvent extraction, for extracting oil, polysaccharides, proteins, polyphenols or hydroxycinnamic acids and as a pre-treatment of the fibrous raffinate. This is especially efficient for the processing of oilseed crops and the production of binderless fiberboards or to prepare technical fibers for composite applications. This has been widely demonstrated on sunflower, jatropha or more recently coriander. Finally, in the bioenergy field, a specific pretreatment process for the production of bioethanol from lignocellulosic feedstock has been developed and is actually in the up-scaling phase. Integrating the use of enzymes in a one-step TSE, this process has been called "bioextrusion"