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International audience; Cell culture on microcarriers emerges as an alternative of two-dimensional culture to produce large cell doses, which are required for cell-based therapies. Herein, we report a versatile and easy solvent-free greener fabrication process to prepare microcarriers based on a biosourced and compostable polymer. The preparation of the microcarrier core, which is based on poly(L-lactide) crystallization from a polymer blend, allows us to easily tune the density, porosity, and size of the microparticles. A bioadhesive coating based on biopolymers, devoid of animal protein and optimized to improve cell adhesion, is then successfully deposited on the surface of the microcarriers. The ability of these new microcarriers to expand human adipose-derived stromal cells with good yield, in semistatic and dynamic conditions, is demonstrated. Finally, bead-to-bead cell transfer is shown to increase the yield of cell production without having to stop the culture. These microcarriers are therefore a promising and efficient green alternative to currently existing systems.

Cet ouvrage est l’aboutissement du programme « Économie sociale et solidaire : acteurs, structures, dynamiques locales – ESS ASDL » financé par la région des Pays de la Loire (2006-2008) qui a rassemblé une quarantaine de chercheurs de l’ouest de la France. Il a bénéficié également d’apports enrichissants de plusieurs collègues français ou étrangers avec lesquels des coopérations ont été nouées. Il s’agit d’un ouvrage pluridisciplinaire croisant les analyses de différentes sciences humaines et sociales (sociologie, économie, géographie, gestion, histoire) pour approfondir la connaissance de cette réalité complexe qu’est l’économie sociale et solidaire. Trois axes de réflexion ont été privilégiés : le premier, celui des formes de l’entrepreneuriat en économie sociale, constitue un élément essentiel pour comprendre la dynamique même de cette économie entre permanences et innovations. Le second, celui de l’emploi et des rapports salariaux au sein de cette économie, met en évidence les fortes tensions existant entre des formes innovantes, sources de progrès, et la persistance de certaines précarités qui peut inquiéter. Enfin, l’ancrage territorial des entreprises de l’économie sociale est illustré à partir d’exemples pris dans divers secteurs. À travers ces trois thématiques, les auteurs apportent un éclairage nouveau et ouvrent des perspectives de réflexion aussi bien pour les acteurs que pour les chercheurs concernés par l’économie sociale et solidaire.

Mats of nanofibers are important as biological scaffolds, (bio)functional electrodes, or smart membranes. Herein, we show that layer-by-layer (LbL) assembly of a wide variety of compounds in nanoporous templates, followed by a straightforward filtration methodology of the nanotubes after membrane dissolution, leads to the fabrication of LbL nanopapers over centimeter square surfaces. The texture of the nanopapers can be easily tuned by varying the rigidity of the nanofibers, which can be achieved by changing their wall thickness, crosslinking them, or developing nanotubes with a core–shell structure. In the nanopapers, the tubes deform by different mechanisms, including flattening, twisting and scrolling, depending on tube rigidity. The possibility to manufacture multilayered nanopapers made of stacks of different nanofibers, or chemically post-functionalize them, is also demonstrated; in addition, the fabrication of enzymatically-active nanopapers is shown. Considering the vast range of materials which can be used for the construction of nanotubes including, e.g., proteins, polysaccharides, conducting polymers or nanoparticles, and the many possible post-functionalization techniques of LbL films, the methodology offers a very flexible route to a virtually limitless collection of functional smart nanopapers.

Auf Ebene der Europäischen Union (EU) war das Jahr 2019 stark geprägt durch nicht abgeschlossene Entscheidungsprozesse. Die Europawahl im Mai, eine verzögerte Bildung der neuen EU-Kommission sowie wiederkehrend aufgeschobene Entscheidungen bezüglich des Ausscheidens Großbritanniens aus der EU haben die Beratungen und Verabschiedung eines mehrjährigen Finanzrahmens für die Jahre nach 2020 beeinträchtigt. Ohne diese Einigung können auch die Beratungen über die konkrete Ausgestaltung der Gemeinsamen Agrarpolitik (GAP) der EU nicht abgeschlossen werden. Daneben war nicht nur die deutsche agrarpolitische Diskussion, vor allem in der zweiten Hälfte des Jahres, durch Proteste von Landwirten geprägt. Neben der Unsicherheit über eine zukünftige Agrarpolitik und die Entwicklung der gesetzlichen Rahmenbedingungen spielt die Ablehnung neuer Freihandelsabkommen und die unterschiedliche Einschätzung der Instrumentenwahl zur Reduzierung von Umweltauswirkungen der Landwirtschaft eine prominente Rolle in der Auseinandersetzung. Zusätzlich hat der zweite vergleichsweise trockene Sommer in Folge die Rolle von Wetterschwankungen und Klimaveränderungen für die landwirtschaftliche Produktion aber auch den Beitrag des Sektors zum Klimawandel in die öffentliche Aufmerksamkeit gerückt. Dieser Beitrag greift einige dieser Aspekte auf und beleuchtet ausgewählte Hintergründe. Auf Ebene des internationalen Handels wird im folgenden Abschnitt die Einigung auf ein Freihandelsabkommen zwischen der EU und den Mercosur-Staaten thematisiert, die derzeitige Handelssituation beschrieben und Bewertungen des sowie Kritik an dem Abkommen zusammengefasst. Die Diskussion über eine zukünfti-ge GAP wird in Abschnitt 3 im Überblick dargestellt. Abschnitt 4 nimmt auf die zunehmende Verschränkung von agrar-, umwelt- und klimapolitischen Feldern Bezug und beleuchtet politische Initiativen und Beschlüsse mit einem besonderen Schwerpunkt auf die angestrebte Reduzierung von Emissionen aus der Landwirtschaft.

The development of a functional in vitro model for microcirculation is an unresolved challenge, with major impact for the creation and regeneration of organs in the tissue engineering. The absence of pre-vascularized engineered tissues limits enormously their efficacy and integration. Therefore, in this study, the in vitro formation of tubular-like structures with human umbilical vein endothelial cells (HUVECs) is investigated thanks to three-dimensional polycarbonate (PC) micro-channel (μCh) scaffolds), surface biofunctionalized with hyaluronic acid/chitosan (HA/CHI) layer-by-layer (LbL) films grafted with adhesive (RGD) and angiogenic (SVV and QK) peptides, alone and in combination. The novelty of this work lies in the formation of capillaries in the order of tens μm, developing spontaneous micro-vessels, without the complexity of micro-fluidic approaches, and in a short time-scale. Ellipsometry, confocal laser scanning microscopy and fluorospectrometry are used to characterize the biofunctionalized micro-channels. PC-μCh scaffolds functionalized with (HA/CHI)12.5 film (PC-LbL) and further grafted with RGD and QK peptides (PC-RGD+QK) or with RGD and SVV peptides (PC-RGD+SVV) are then tested for in vitro blood vessel formation. These assays evidence a rapid formation of tubular-like structures after 2h of incubation. Moreover, co-culture system involving HUVECs and human pericytes derived from placenta (hPCs-PL) stabilizes the tubes for longer time.

The immobilization of proteins to impart specific functions to surfaces is topical for chemical engineering, healthcare and diagnosis. Layer-by-Layer (LbL) self-assembly is one of the most used method to immobilize macromolecules on surfaces. It consists in the alternate adsorption of oppositely charged species, resulting in the formation of a multilayer. This method in principle allows any charged object to be immobilized on any surface, from aqueous solutions. However, when it comes to proteins, the promises of versatility, simplicity and universality that the LbL approach holds are unmet due to the heterogeneity of protein properties. In this review, the literature is analyzed to make a generic approach emerge, with a view to facilitate the LbL assembly of proteins with polyelectrolytes (PEs). In particular, this review aims at guiding the choice of the PE and the building conditions that lead to the successful growth of protein-based multilayered self-assemblies.

A play in three acts by Charles Albert Demoustier,” Les femmes” presented for the first time at Théâtre de la Nation, 19 April 1793. Published: “An sixieme”, [that is, 1797 or 1798].Extent: 56 pages (54 numbered and 2 unnumbered); the final page numbered 45 is a misprint for 54. Page [56] not imaged.Bound in a volume with other French plays of the same period.

Immobilization of enzymes on supporting materials for biocatalysis is highly desired for industrial applications, because it endows the biocatalytic platform with significant advantages compared to free enzymes, e.g., easy separation, re-usability, and long-term stability. However, the possible denaturation of immobilized enzymes by the underlying substrate or crosslinking, and the limited amount of attached enzymes, often results in a low enzymatic activity. Here, we employ polyelectrolytes to assemble glucose oxidase in thick films in a layer-by-layer (LbL) way. By screening a large range of conditions, we show that the immobilized enzymes may retain their intrinsic structure and display a high activity when deposited in suitable conditions with the appropriate polycation. Moreover, the activity of formed multilayer enzyme films can be tuned depending on deposition conditions. We also demonstrate swelling of the film by the reaction medium by in-situ AFM measurements, with the film behaving as a hydrogel in which the enzymatic substrate can easily access the active site of enzymes immobilized all along the film. Hence, despite the complexity of protein adsorption in LbL films, conditions for stable growth of active enzymatic films of tunable activity can be found, offering a promising way to design highly active enzyme-immobilized catalytic platforms.

PURPOSE: The aim of this study is to optimize fibrin matrix composition in order to mimic human ovarian tissue architecture for human ovarian follicle encapsulation and grafting. METHODS: Ultrastructure of fresh human ovarian cortex in age-related women (n = 3) and different fibrin formulations (F12.5/T1, F30/T50, F50/T50, F75/T75), rheology of fibrin matrices and histology of isolated and encapsulated human ovarian follicles in these matrices. RESULTS: Fresh human ovarian cortex showed a highly fibrous and structurally inhomogeneous architecture in three age-related patients, but the mean ± SD of fiber thickness (61.3 to 72.4 nm) was comparable between patients. When the fiber thickness of four different fibrin formulations was compared with human ovarian cortex, F50/T50 and F75/T75 showed similar fiber diameters to native tissue, while F12.5/T1 was significantly different (p value

A process combining electrochemical nanofabrication by hard templating with the use of a masking strategy and surface functionalization methods, is developed to produce arrays of gold nanopillars of spatially-controlled surface chemistry. Therefore, a gold nanopillar array is first fabricated by performing metal electrochemical deposition into a track-etched membrane supported on a gold substrate. After dissolution of the membrane, a protective polymer layer is deposited on the array and partially etched to specifically reveal the top of the nanopillars. Then, a polythiolactone-based copolymer is grafted on the upper part of the nanopillars. Afterwards, the sacrificial polymer layer is dissolved to reveal the non-functionalized surface corresponding to the lower part of the gold nanopillars and the background surface. This surface is subsequently modified by a self-assembled monolayer (SAM) of alkylthiol molecules which leads to nanostructured surfaces with spatio-selective surface chemistry. The grafting of gold nanoparticles and of a bioadhesive peptide on the top and on the background of the nanopillar array, respectively, is performed to prove the versatility of the approach to produce bifunctionalized nanopillar arrays for biological, biosensing or (bio)catalysis applications.

Species distribution models (SDMs) have been increasingly used over the past decades to characterise the spatial distribution and the ecological niche of various taxa. Validating predicted species distribution is important, especially when producing broad-scale models (i.e. at continental or oceanic scale) based on limited and spatially aggregated presence-only records. In the present study, several model calibration methods are compared and guidelines are provided to perform relevant SDMs using a Southern Ocean marine species, the starfish Odontaster validus Koehler, 1906, as a case study. The effect of the spatial aggregation of presence-only records on modelling performance is evaluated and the relevance of a target-background sampling procedure to correct for this effect is assessed. The accuracy of model validation is estimated using k-fold random and spatial cross-validation procedures. Finally, we evaluate the relevance of the Multivariate Environmental Similarity Surface (MESS) index to identify areas in which SDMs accurately interpolate and conversely, areas in which models extrapolate outside the environmental range of occurrence records. Results show that the random cross-validation procedure (i.e. a widely applied method, for which training and test records are randomly selected in space) tends to over-estimate model performance when applied to spatially aggregated datasets. Spatial cross-validation procedures can compensate for this over-estimation effect but different spatial cross-validation procedures must be tested for their ability to reduce over-fitting while providing relevant validation scores. Model predictions show that SDM generalisation is limited when working with aggregated datasets at broad spatial scale. The MESS index calculated in our case study show that over half of the predicted area is highly uncertain due to extrapolation. Our work provides methodological guidelines to generate accurate model assessments at broad spatial scale when using limited and aggregated presence-only datasets. We highlight the importance of taking into account the presence of spatial aggregation in species records and using non-random cross-validation procedures. Evaluating the best calibration procedures and correcting for spatial biases should be considered ahead the modelling exercise to improve modelling relevance., SCOPUS: ar.j, info:eu-repo/semantics/published