Expression of lactate dehydrogenase, myosin heavy chain and myogenic regulatory factor genes in rabbit embryonic muscle cell cultures.

International audienceThe expression of myogenic regulatory factors (MRFs), lactate dehydrogenase (LDH) and myosin heavy chains (MyHC), as markers of myogenesis, metabolism and contractility respectively, were investigated during differentiation of rabbit embryonic muscle cells in primary culture. Myf5, MyoD and myogenin mRNAs were abundantly expressed at day 1 of culture. The expression of Myf5 and MyoD mRNA transcripts decreased sharply as myoblasts fused and differentiated into myotubes, whilst myogenin mRNA was maintained throughout the duration of the culture. In contrast, MRF4 mRNA was weakly expressed on day 1 of culture, its expression increased slightly as myoblasts fused and reached a maximum level in 7-day-old cultures containing striated myofibres. The specific activity of LDH increased linearly during myoblast proliferation and fusion. In 7-day-old cultures, LDH-M mRNA (dominant in glycolytic muscles) and LDH-H mRNA (predominant in perinatal and oxidative muscles) represented 38% and 62% of total LDH mRNA respectively. At this stage, immunocytochemical staining with perinatal and adult-type MyHC antibodies showed that embryonic and perinatal MyHC isoforms were expressed in all myotubes, while few of them were stained by type I MyHC antibody. However, none of them expressed adult type II MyHC. The latter results were further supported by RT-PCR analysis of adult-type MyHC mRNA which showed that only the type I MyHC mRNA transcript was expressed. These data were in agreement with those reported in vivo on perinatal rabbit muscles. They differed from those obtained on cultured satellite cells isolated from adult rabbit fast-twitch or slow-twitch muscles which did not express embryonic MyHC, and instead expressed fast- or slow-type MyHC according to their muscle origin. Taken together, these results further suggest that myogenic mononucleated cells express different properties in vitro according to their developmental origin as well as properties related to those of the muscles from which they were isolated

Quoi de neuf sur l'histoire des entreprises en France ?

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Career Advancement in a Family-Owned French Construction Firm Under Changing Labor Legislation and Market Demand, 1946-1985

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Contribution à une meilleure explicitation du vocabulaire dans le domaine des solutions dites « alternatives » de gestion des eaux pluviales urbaines

La façon de gérer les eaux pluviales urbaines est en train de changer rapidement pour répondre à des enjeux de plus en plus nombreux et complexes : maîtrise des flux d’eau et de polluants produits par la ville, préservation des ressources, meilleure intégration dans le paysage, prise en compte d’objectifs sociaux, économiques, climatiques, écologiques et environnementaux, etc. De plus, ce changement s’inscrit dans des évolutions plus larges concernant à la fois la ville et la gestion d’un patrimoine assainissement vieillissant et coûteux à entretenir. Pour répondre à ces enjeux et développer des solutions de gestion adaptées à ces nouveaux besoins, les hydrologues et les spécialistes de l’assainissement doivent travailler avec des acteurs de plus en plus nombreux qui abordent la question avec des cultures très différentes les unes des autres. Dans ce contexte, la terminologie devient très importante pour pouvoir échanger et se comprendre. Or le vocabulaire comme les concepts sont encore en phase de construction. L’objectif de ce texte, rédigé par un panel varié de spécialistes du domaine de l’hydrologie urbaine, vise à montrer la grande diversité du vocabulaire aujourd’hui associé à la gestion des eaux pluviales, et propose une grille de lecture pour clarifier autant que possible les principales notions. Il ne s’agit pas de tomber dans le piège d’une normalisation des mots, mais d’aider à une meilleure compréhension entre acteurs. Ce travail porte sur les concepts généraux qui structurent la réflexion et la stratégie, ainsi que sur le vocabulaire technique et en particulier sur la façon de distinguer les solutions. Ce document est destiné à tous les acteurs de la ville, d’une part, et de la gestion de l’eau et de l’environnement, d’autre part. Il n’a pas la prétention de clore le débat.The way urban stormwater is managed is changing rapidly to meet increasingly numerous and complex challenges: control of water flows and pollutants produced by the city, preservation of resources, better integration into the landscape, consideration of social, economic, climatic, ecological and environmental objectives, etc. In addition, this change is part of broader developments concerning both the city and the management of an aging and expensive to maintain sewerage heritage. To meet these challenges and develop management solutions fitted to these new needs, hydrologists and drainage specialists must work with an increasing number of actors who approach the issue with very different cultures. In this context, terminology becomes very important to be able to exchange and understand each other. However, the vocabulary, like the concepts, are still in the construction phase. The objective of this paper, written by a large panel of specialists in the field, aims to show the great diversity of the vocabulary associated with stormwater management today, and proposes a reading grid to clarify as much as possible the main concepts. The aim is not to fall into the trap of a standardizing words, but to help improve understanding between actors. This paper covers the general concepts that structure thinking and strategy, as well as technical vocabulary and in particular how to distinguish solutions. This document is intended for all the actors of the city on the one hand and of water and the environment management on the other hand

Design and manufacturing of a multi-zone phase-shifting coronagraph mask for extremely large telescopes

Context. High-contrast imaging of exoplanets around nearby stars with future large-segmented apertures requires starlight suppression systems optimized for complex aperture geometries. Future extremely large telescopes (ELTs) equipped with high-contrast instruments operating as close as possible to the diffraction limit will open a bulk of targets in the habitable zone around M-stars. In this context, the phase-induced amplitude apodization complex mask coronagraph (PIAACMC) is a promising concept for high-efficiency coronagraphic imaging at small angular separations with segmented telescopes. Aims. The complex focal plane mask of the PIAACMC is a multi-zone, phase-shifting mask comprised of tiled hexagons that vary in depth. The mask requires micro-fabrication techniques because it is generally made of hundreds micron-scale hexagonal zones with depths ranging over a few microns. We aim to demonstrate that the complex focal plane mask of a PIAACMC with a small inner working angle can be designed and manufactured for segmented apertures. Methods. We report on the numerical design, specifications, manufacturing, and characterization of a PIAACMC complex focal plane mask for the segmented pupil experiment for exoplanet detection facility. Results. Our PIAACMC design offers an inner working angle of 1.3 λ/D and is optimized for a 30% telescope-central-obscuration ratio including six secondary support structures (ESO/ELT design). The fabricated reflective focal plane mask is made of 499 hexagons, and the characteristic size of the mask features is 25 μm, with depths ranging over ±0.4 μm. The mask sag local deviation is measured to an average error of 3 nm and standard deviation of 6 nm rms. The metrological analysis of the mask using interferential microscopy gives access to an in-depth understanding of the component’s optical quality, including a complete mapping of the zone depth distribution zone-depth distribution. The amplitude of the errors in the fabricated mask are within the wavefront control dynamic range. Conclusions. We demonstrate the feasibility of fabricating and characterizing high-quality PIAA complex focal plane masks

Contribution à une meilleure explicitation du vocabulaire dans le domaine des solutions dites « alternatives » de gestion des eaux pluviales urbaines

International audienceThe way urban stormwater is managed is changing rapidly to meet increasingly numerous and complex challenges: control of water flows and pollutants produced by the city, preservation of resources, better integration into the landscape, consideration of social, economic, climatic, ecological and environmental objectives, etc. In addition, this change is part of broader developments concerning both the city and the management of an aging and expensive to maintain sewerage heritage. To meet these challenges and develop management solutions fitted to these new needs, hydrologists and drainage specialists must work with an increasing number of actors who approach the issue with very different cultures. In this context, terminology becomes very important to be able to exchange and understand each other. However, the vocabulary, like the concepts, are still in the construction phase. The objective of this paper, written by a large panel of specialists in the field, aims to show the great diversity of the vocabulary associated with stormwater management today, and proposes a reading grid to clarify as much as possible the main concepts. The aim is not to fall into the trap of a standardizing words, but to help improve understanding between actors. This paper covers the general concepts that structure thinking and strategy, as well as technical vocabulary and in particular how to distinguish solutions. This document is intended for all the actors of the city on the one hand and of water and the environment management on the other hand. It does not claim to close the debate.La façon de gérer les eaux pluviales urbaines est en train de changer rapidement pour répondre à des enjeux de plus en plus nombreux et complexes : maîtrise des flux d’eau et de polluants produits par la ville, préservation des ressources, meilleure intégration dans le paysage, prise en compte d’objectifs sociaux, économiques, climatiques, écologiques et environnementaux, etc. De plus, ce changement s’inscrit dans des évolutions plus larges concernant à la fois la ville et la gestion d’un patrimoine assainissement vieillissant et coûteux à entretenir. Pour répondre à ces enjeux et développer des solutions de gestion adaptées à ces nouveaux besoins, les hydrologues et les spécialistes de l’assainissement doivent travailler avec des acteurs de plus en plus nombreux qui abordent la question avec des cultures très différentes les unes des autres. Dans ce contexte, la terminologie devient très importante pour pouvoir échanger et se comprendre. Or le vocabulaire comme les concepts sont encore en phase de construction. L’objectif de ce texte, rédigé par un panel varié de spécialistes du domaine de l’hydrologie urbaine, vise à montrer la grande diversité du vocabulaire aujourd’hui associé à la gestion des eaux pluviales, et propose une grille de lecture pour clarifier autant que possible les principales notions. Il ne s’agit pas de tomber dans le piège d’une normalisation des mots, mais d’aider à une meilleure compréhension entre acteurs. Ce travail porte sur les concepts généraux qui structurent la réflexion et la stratégie, ainsi que sur le vocabulaire technique et en particulier sur la façon de distinguer les solutions. Ce document est destiné à tous les acteurs de la ville, d’une part, et de la gestion de l’eau et de l’environnement, d’autre part. Il n’a pas la prétention de clore le débat