Genetic regulation of pituitary gland development in human and mouse

Normal hypothalamopituitary development is closely related to that of the forebrain and is dependent upon a complex genetic cascade of transcription factors and signaling molecules that may be either intrinsic or extrinsic to the developing Rathke’s pouch. These factors dictate organ commitment, cell differentiation, and cell proliferation within the anterior pituitary. Abnormalities in these processes are associated with congenital hypopituitarism, a spectrum of disorders that includes syndromic disorders such as septo-optic dysplasia, combined pituitary hormone deficiencies, and isolated hormone deficiencies, of which the commonest is GH deficiency. The highly variable clinical phenotypes can now in part be explained due to research performed over the last 20 yr, based mainly on naturally occurring and transgenic animal models. Mutations in genes encoding both signaling molecules and transcription factors have been implicated in the etiology of hypopituitarism, with or without other syndromic features, in mice and humans. To date, mutations in known genes account for a small proportion of cases of hypopituitarism in humans. However, these mutations have led to a greater understanding of the genetic interactions that lead to normal pituitary development. This review attempts to describe the complexity of pituitary development in the rodent, with particular emphasis on those factors that, when mutated, are associated with hypopituitarism in humans

Equilibres stables et metastables dans le systeme Fe-Zn-Al en relation avec les processus de galvanisation a 450deg.C

SIGLEAvailable from INIST (FR), Document Supply Service, under shelf-number : T 79841 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc

Sibling cannibalism among juvenile vundu under controlled conditions. II. Effect of body weight and environmental variables on the periodicity and intensity of type II cannibalism

peer reviewedCannibalism among starved groups of juvenile (19-48 days old) vundu catfish Heterobranchus longifilis was 66.5 % nocturnal, and its impact under modified day length was proportional to the duration of the dark phase. Shallow depth and high population density decreased the intensity of cannibalism, whereas low density and deeper environments had an opposite effect. The presence of refuges had no significant effect on cannibalism. The maintenance (R maint) and maximum (R max) daily food ration (%/day) of cannibals feeding on live preys were modelled as R maint = 3,899 Wc exp-0,327 (r2=0,684, d.f.= 5), where Wc was the body weight of the cannibal(g).The latter model indicated that the impact of a cannibal on a population decreased by a 20% margin each time the cannibal doubled its body weight, and suggested that cannibalism among vundu would become insignificant for cannibals heavier than 30 g. The significance of these findings is discussed within the contexts of vundu aquaculture and of general, conceptual models of the dynamics of cannibalism among fishes

Feeding in darkness alleviates density-dependent growth of juvenile vundu catfish

Sibling juvenile vundu Heterobranchus longifilis reared at 27 ± 1 °C under 12L:12D were fed during the day, at night or over the entire 24-h cycle, for periods of 14-15 d. Nighttime feeding gave the highest growth rates, best feed conversion, lowest mortality, fewest losses due to cannibalism and least growth heterogeneity. The trends were seen in fish of all ages and weights (31−101 d and 0.3−30.0 g), but differences were significant only for the smallest fish that were reared at the lowest stocking biomass (< 3.5 g·L−1). The effects of daytime and nighttime feeding were examined in 151-d old (85 g) juveniles stocked at different biomasses (3.4 and 13.6 g·L−1). The growth of vundu was density-dependent, being impaired at low stocking density, but this was substantially mitigated under nighttime feeding. Rearing at high stocking density, feeding at night or in darkness, may act through similar mechanisms that involve changes in the level of aggressive behaviour. It is suggested that nighttime feeding in intensive catfish culture could be replaced by 24-h feeding under conditions of permanent darkness

Stéréoscopie et illusion

À travers l'analyse des premières photographies stéréoscopiques du xixe siècle, des films en 3Ds en passant par les applications en réalité virtuelle, cet ouvrage réunit les contributions d’artistes, de stéréographes, de cinéastes et de chercheurs qui dressent un état des lieux sur les connaissances scientifiques et les expérimentations artistiques depuis le xxe siècle ainsi que leurs applications dans les pratiques contemporaines. Les concepts d’illusion partielle, d’auto-illusion, d’indiscernabilité entre impression de réalité et de spectralité sont mis en relation avec l’esthétique stéréoscopique de films en 3Ds ou d’installations de Réalité Virtuelle. Cette réflexion collective constitue l’une des étapes du programme de recherche « Les Arts trompeurs. Machines. Magie. Médias. ».The stereoscopic illusion is, most of the time, associated with digital images. Such approach occludes its history: indeed, the stereoscopic illusion is the result of a century of research, that aim at wondering people by manipulating their senses thanks to the impression of “relief” stereoscopic images give them

Corrosion Mechanisms of Steel and Cast Iron by Molten Aluminum

International audienceThe corrosion mechanisms by liquid aluminum of three industrial materials have been studied: unalloyed steel (UAS), and ferritic and modified pearlitic cast irons (FCI and PCI, respectively). The behavior of these materials when in contact with liquid aluminum is different. Aluminum diffuses deep into the UAS and forms intermetallic compounds with iron at the surface and in the steel matrix. At the surface, only Fe2Al5 and FeAl3 are found. In the matrix, FeAl2 also is formed in agreement with the equilibrium Fe-Al diagram. From the matrix to FeAl2, the Al content in the ferrite increases progressively until Al saturation is reached. At this step, black elongated precipitates (Al4C3 and/or graphite) appear. Graphite lamellas present in both FCI and PCI constitute an efficient barrier to the Al diffusion. The high silicon content of the FCI leads to the formation of a phase free from Al and saturated in Si. For the PCI, a thin layer rich in Al and Si, which is formed between the matrix and Fe2Al5, limits the diffusion of atoms. The effects of Cr and P added in the PCI also are discussed