Ni–W diffusion barrier: Its influence on the oxidation behaviour of a β-(Ni,Pt)Al coated fourth generation nickel-base superalloy

A Ni–W base diffusion barrier (DB) has been developed to limit interdiffusion between a fourth generation Ni-base superalloy (MCNG) and a Pt-modified nickel aluminide bondcoat. After long term oxidation, the DB layer permits to reduce the Al depletion in the coating and to delay the phase transformations in the coating. But despite this result, the oxidation behaviour of the system with DB is slightly worse than without the DB. This difference may be caused by the addition of S and/orWin the coating of the system with the DB. The DB layer also delays the Secondary Reaction Zone (SRZ) formation. Nevertheless, the propagation of the SRZ is similar in systems with and without a DB, with growth kinetics which are driven by interdiffusion

Development of a NiW in-situ diffusion barrier on a fourth generation nickel-base superalloy

A diffusion barrier based on a NiW electrolytic coating has been developed to limit interdiffusion between a Ni-base superalloy (MCNG) and a β-NiAl bondcoating. Isothermal oxidation tests of 50h at 1100°C confirmed that W-rich layer formed with NiW coating modifies the oxidation behaviour of the bondcoat and limits interdiffusion. The diffusion barrier reduced β-NiAl γ’-Ni3Al transformation in the bondcoating and prevented SRZ formation

The influence of hay steaming on clinical signs and airway immune response in severe asthmatic horses

ackground Avoidance of antigenic stimuli was found to significantly reverse airway obstruction of horses with severe equine asthma (sEA). To date, no published study investigated the influence of steaming hay on lower airway condition of sEA-affected horses. The objectives were to determine the clinical, cytological and cytokine respiratory responses of both sEA and control (CTL) horses experimentally exposed to steamed or dry hay. Results A cohort of 6 sEA horses and 6 CTL horses was involved in this field study. On day 0, both groups were fed with steamed hay for 5 consecutive days, followed by a wash-out period of 26 days prior to be fed with dry hay for 5 consecutive days. Investigations performed 2 days prior to and 5 days after each challenge included clinical score, tracheal mucus accumulation, and bronchoalveolar lavage fluid (BALF) cytology and cytokine mRNA expression. Feeding steamed hay significantly decreased its mould content (P < 0.001). Mucus score significantly increased when feeding dry hay (P = 0.01). No significant influence of challenge type was found on clinical score. Percentages of neutrophils (P < 0.001) as well as mRNA expression of IL-1β (P = 0.024), IL-6R (P = 0.021), IL-18 (P = 0.009) and IL-23 (P = 0.036) in BALF of sEA affected horses were significantly increased after both (steamed and dry hay) challenges. Relative mRNA expression of IL-1β, IL-6R and IL-23 in BALF were also significantly correlated to neutrophil percentages and both clinical and tracheal mucus score. Conclusions Steaming significantly decreased mould content but inconsistently influenced the respiratory response of sEA affected horses when fed hay. Based on BALF cytology and cytokine profiles, its relevance might be controversial as a non-medicinal therapy for sEA-affected horses

Comparative proteome analysis of human epithelial ovarian cancer

<p>Abstract</p> <p>Background</p> <p>Epithelial ovarian cancer is a devastating disease associated with low survival prognosis mainly because of the lack of early detection markers and the asymptomatic nature of the cancer until late stage. Using two complementary proteomics approaches, a differential protein expression profile was carried out between low and highly transformed epithelial ovarian cancer cell lines which realistically mimic the phenotypic changes observed during evolution of a tumour metastasis. This investigation was aimed at a better understanding of the molecular mechanisms underlying differentiation, proliferation and neoplastic progression of ovarian cancer.</p> <p>Results</p> <p>The quantitative profiling of epithelial ovarian cancer model cell lines TOV-81D and TOV-112D generated using iTRAQ analysis and two-dimensional electrophoresis coupled to liquid chromatography tandem mass spectrometry revealed some proteins with altered expression levels. Several of these proteins have been the object of interest in cancer research but others were unrecognized as differentially expressed in a context of ovarian cancer. Among these, series of proteins involved in transcriptional activity, cellular metabolism, cell adhesion or motility and cytoskeleton organization were identified, suggesting their possible role in the emergence of oncogenic pathways leading to aggressive cellular behavior.</p> <p>Conclusion</p> <p>The differential protein expression profile generated by the two proteomics approaches combined to complementary characterizations studies will open the way to more exhaustive and systematic representation of the disease and will provide valuable information that may be helpful to uncover the molecular mechanisms related to epithelial ovarian cancer.</p

Relation between mean arterial pressure and renal function in the early phase of shock: a prospective, explorative cohort study

International audienceIntroduction: Because of disturbed renal autoregulation, patients experiencing hypotension-induced renal insult might need higher levels of mean arterial pressure (MAP) than the 65 mmHg recommended level in order to avoid the progression of acute kidney insufficiency (AKI)

A robust and reliable methodology to perform GECI-based multi-time point neuronal calcium imaging within mixed cultures of human iPSC-derived cortical neurons

IntroductionHuman induced pluripotent stem cells (iPSCs), with their ability to generate human neural cells (astrocytes and neurons) from patients, hold great promise for understanding the pathophysiology of major neuropsychiatric diseases such as schizophrenia and bipolar disorders, which includes alterations in cerebral development. Indeed, the in vitro neurodifferentiation of iPSCs, while recapitulating certain major stages of neurodevelopment in vivo, makes it possible to obtain networks of living human neurons. The culture model presented is particularly attractive within this framework since it involves iPSC-derived neural cells, which more specifically differentiate into cortical neurons of diverse types (in particular glutamatergic and GABAergic) and astrocytes. However, these in vitro neuronal networks, which may be heterogeneous in their degree of differentiation, remain challenging to bring to an appropriate level of maturation. It is therefore necessary to develop tools capable of analyzing a large number of cells to assess this maturation process. Calcium (Ca2+) imaging, which has been extensively developed, undoubtedly offers an incredibly good approach, particularly in its versions using genetically encoded calcium indicators. However, in the context of these iPSC-derived neural cell cultures, there is a lack of studies that propose Ca2+ imaging methods that can finely characterize the evolution of neuronal maturation during the neurodifferentiation process.MethodsIn this study, we propose a robust and reliable method for specifically measuring neuronal activity at two different time points of the neurodifferentiation process in such human neural cultures. To this end, we have developed a specific Ca2+ signal analysis procedure and tested a series of different AAV serotypes to obtain expression levels of GCaMP6f under the control of the neuron-specific human synapsin1 (hSyn) promoter.ResultsThe retro serotype has been found to be the most efficient in driving the expression of the GCaMP6f and is compatible with multi-time point neuronal Ca2+ imaging in our human iPSC-derived neural cultures. An AAV2/retro carrying GCaMP6f under the hSyn promoter (AAV2/retro-hSyn-GCaMP6f) is an efficient vector that we have identified. To establish the method, calcium measurements were carried out at two time points in the neurodifferentiation process with both hSyn and CAG promoters, the latter being known to provide high transient gene expression across various cell types.DiscussionOur results stress that this methodology involving AAV2/retro-hSyn-GCaMP6f is suitable for specifically measuring neuronal calcium activities over multiple time points and is compatible with the neurodifferentiation process in our mixed human neural cultures

Le tuf calcaire de La Celle-sur-Seine (Seine et Marne) : nouvelles données sur un site clé du stade 11 dans le Nord de la France

De nouvelles études morphostratigraphiques et biostratigraphiques ainsi que des datations ont été entreprises sur le célèbre dépôt de tuf calcaire de La Celle-sur-Seine afin d'obtenir une reconstruction détaillée des successions paléoenvironnementales et climatiques enregistrées dans cette formation interglaciaire du Pléistocène moyen. L'approche développée a privilégié l'aspect pluridisciplinaire afin d'exploiter la richesse paléontologique du gisement, de mieux appréhender ses caractères morphostratigraphiques et de préciser sa position chronologique. Les premiers résultats obtenus à partir des études malacologiques montrent que le dépôt, composé de tufs et de niveaux limono-argileux, s'est construit en progradant le long du versant. Ainsi l'épaisseur totale de la formation atteint près de 9 mètres. Les malacofaunes permettent de reconstituer une évolution paléoenvironnementale correspondant au début puis à l'optimum d'une phase climatique interglaciaire. Les niveaux sommitaux sont, eux, caractérisés par un net recul de la couverture forestière.La création de nouveaux profils stratigraphiques a permis la découverte dans un niveau de limon gris tufacé d'une abondante faune de mammifères accompagnée par quelques silex taillés. Cet horizon appartient à la malacozone la plus riche en taxons thermophiles qui est interprétée comme la phase optimum de l'Interglaciaire. La signification environnementale et climatique du cortège mammalogique, qui comprend en particulier de l'hippopotame et du macaque, corrobore les résultats malacologiques. L'industrie lithique est de type bifaciale en cohérence avec les récoltes de bifaces acheuléens effectuées à la fin du 19ème siècle. La composition du cortège de mollusques permet de rapprocher la faune de La Celle de "l'assemblage à Lyrodiscus", caractéristique des tufs du stade 11 dans le nord-ouest de l'Europe. Cette attribution chronologique est confirmée par les premières mesures radiométriques obtenus par U-Th sur des échantillons de tuf induré et par RPE/U-Th sur une dent de cheval. Enfin la révision des collections paléontologiques d'empreintes foliaires permet, en conjonction avec les données malacologiques, d'initier la discussion sur l'interprétation paléoclimatique du biome à Lyrodiscus. L'association floristique et faunique de La Celle qui comprend quelques taxons arboréens méditerranéens et nombre de gastéropodes éteints ou de répartition actuelle centre-européenne et océanique rend compte d'un environnement tempéré de forêt humide. La présence de ces espèces allochtones dans le nord de la France est mise en parallèle avec la durée exceptionnellement longue du Stade Isotopique Marin (SIM) 11 et de faibles amplitudes de températures saisonnières, qui auraient permis à plusieurs taxons méridionaux de coloniser cette zone septentrionale, plutôt qu'avec un climat plus tempéré que l'actuel.New morpho and biostratigraphical studies have been undertaken at the famous calcareous tufa deposit of La Celle-sur-Seine in order to obtain a detailed paleoenvironmental and climatic reconstruction from this Middle Pleistocene Interglacial formation. Multiproxy approach allows to study palaeontological contain of the tufa as well as its morphostratigraphical aspects and chronological allocation. First results from malacological study show that the tufa edificated downwards the slope reaching a total thickness of 9 metres high. Moreover molluscs show palaeoenvironmental succession corresponding to the early part of an Interglacial period followed by an optimum phase. Finally, at the top of the deposit faunas clearly indicate decrease of forest biotopes.Excavation of new profiles have allowed to discover a grey silty tufa horizon (lgt) yielding abundant mammal remains and a few lithic artefacts. This level is part of the molluscs zone 3 corresponding to the climatic optimum. Palaeoenvironmental and climatic conditions inferred from mammal assemblage (including Hippopotamus and Macaca) strengthened the malacological interpretation. The lithic industry is identified as Acheulean and appears in agreement with earliest handaxes discoveries during the late 19th century.La Celle malacological fauna belongs to the well-known MIS 11 "Lyrodiscus assemblage" in north-west Europe. This chronological allocation is confirmed by first U-series radiometric measures. Finally reappraisal of leaf print collections allows together with malacological data to discuss palaeoclimatic interpretation of the "Lyrodiscus biome". Flora and fauna from La Celle include a few mediterranean trees and several extinct gastropods together with few molluscs of central Europe modern range, allowing to describe a forest and humid lanscape. Presence of these peculiar species in northern France is thought to be related with the long length of MIS 11 and lower seasonal temperature contrast, that have allowed northern colonisation by southern species, rather than with occurrence of temperature higher than today