ENDOGLIN is dispensable for vasculogenesis, but required for vascular endothelial growth factor-induced angiogenesis

ENDOGLIN (ENG) is a co-receptor for transforming growth factor-β (TGF-β) family members that is highly expressed in endothelial cells and has a critical function in the development of the vascular system. Mutations in Eng are associated with the vascular disease known as hereditary hemorrhagic telangiectasia type l. Using mouse embryonic stem cells we observed that angiogenic factors, including vascular endothelial growth factor (VEGF), induce vasculogenesis in embryoid bodies even when Eng deficient cells or cells depleted of Eng using shRNA are used. However, ENG is required for the stem cell-derived endothelial cells to organize effectively into tubular structures. Consistent with this finding, fetal metatarsals isolated from E17.5 Eng heterozygous mouse embryos showed reduced VEGF-induced vascular network formation. Moreover, shRNA-mediated depletion and pharmacological inhibition of ENG in human umbilical vein cells mitigated VEGF-induced angiogenesis. In summary, we demonstrate that ENG is required for efficient VEGF-induced angiogenesis

Quantitative fatigue fracture surface analysis on railway axles

International audienceFor passengers' safety and to improve railway axles maintenance, the French railway company, SNCF, studies the evolution of crack length in function of time in fatigue loading situations. To achieve this, it's necessary to know the in-service axle loading. As in-service measurements are very expensive and specific, authors decided to study fracture surfaces of components cracked or broken in service. So, the question is: how can we determine the loading history of a cracked component studying the fracture surfaces? This amounts to determining fracture mechanics parameters such as the maximum stress intensity factor Kmax along the crack path. Authors have ever transferred a quantitative fractographic analysis method from aluminium alloys to axle steel EA4T. This method is based on quantification of significant fractographic features such as striations. But, due to limits of this one, authors decided to add another technique based on X-ray diffraction measurements. In this paper, results of these methods are highlighted and discussed

40Ar/39Ar ages and duration across the Triassic-Jurassic boundary of the Central Atlantic Magmatic Province volcanism in Morocco and Portugal.

The Central Atlantic Magmatic Province (CAMP) is the world's largest known continental igneous province and is contemporaneous with the Triassic\u2013Jurassic (T\u2013J) boundary that marks one of the five largest biological extinctions in the last 600 Ma. Although constraints on the duration of the CAMP volcanism remain yet poorly defined, the assumption that the CAMP may have had a causal relationship with the climatic and biotic crisis was suggested [Marzoli, A., Bertrand, H., Knight, K., Cirilli, S., Buratti, N, Verati, C., Nomade, S., Renne, P.R., Youbi, N., Martini, R., Allenbach, K., Neuwerth, R., Rapaille, C., Zaninetti, L., Bellieni, G., 2004. Synchrony of the Central Atlantic magmatic province and the Triassic\u2013Jurassic boundary climatic and biotic crisis. Geology 32, 973\u2013976.]. In this paper, we present new 40Ar/39Ar ages on basaltic flows from Moroccan (central High Atlas, Oujda and Argana) and Portuguese (Algarve and Santiago do Cac\ue9m) basins where CAMP lava flows are interlayered with T\u2013J sedimentary sequences. In the Moroccan basins, where the basalts were erupted across the T\u2013J boundary, well defined 40Ar/39Ar plateau ages (n=12) for more than 90% of the total erupted volume of CAMP basalts range from 197.8\ub10.7 Ma to 201.7\ub12.4 Ma and display a main restricted peak at 199.1\ub11 Ma providing a precise estimate of the 40Ar/39Ar age of the T\u2013J boundary, concordant with the current U\u2013Pb age [199.6\ub10.3 Ma; P\ue1lfy, J., Mortensen, J.K, Carter, E.S., Smith, P.L., Friedman, R.M., Tipper, H.W., 2000. Timing the end-Triassic mass extinction: First on land, then in the sea? Geology 28, 39\u201342.]. The topmost lava flows (recurrent unit) yield a significantly younger mean age of 196.6\ub10.6 Ma, highlighting late episodic eruption of CAMP magmas. These late basalts represent a small magma volume (b10% of the total), which was erupted most likely due to asthenospheric upwelling and lithospheric extension within the T\u2013J central High Atlas basins. In the Portuguese basins, stratigraphical and palynological studies of the associated continental sedimentary sequence underlying the volcanic units suggest an age close to the T\u2013J boundary for the CAMP basaltic flows. This is confirmed by new 40Ar/39Ar data for the Portuguese basalts, which provide the first accurate radio-isotopic ages for lava flows in the European CAMP, with two plateau ages yielding a mean value of 198.1\ub10.4 Ma. These plateau ages (plus three concordant mini-plateau ages) suggest synchronous rifting and volcanism both in south-western Europe and Morocco (central High Atlas and Oujda basins)

A Method for quantitative fatigue fracture surface analysis

International audienceWhen fatigue failure occurs, it is important to identify the cause of failure. In terms of fracture mechanics, the ideal method is the one that permits the determination of maximum stress intensity factor, Kmax and the load ratio R from a fracture analysis. Different techniques have been developed and have met with limited success. Such techniques include evaluation of roughness, fractal analysis or measurement of hardness. The authors have developed a method based on the determination of the areal coverage of significant fractographic features on the fracture surface. In this paper, after a brief presentation of the method, results obtained on a structural steel are highlighted and discussed

Anion production in high-velocity cluster-atom collisions; the electron capture process revisited

Anion production cross sections in collisions between C-n(+), Cn carbon clusters (n <= 5) and helium atoms have been measured in high-velocity collisions (v = 2.25 and 2.6 au). This paper focuses on two of the three processes responsible for the C-n(-) production, namely double electron capture (DEC) onto C-n(+) cations and single electron capture onto neutral (SECN) C-n. They were experimentally distinguished from a gaseous thickness dependence study. Dissociative and non-dissociative cross sections were measured and, in the case of DEC, all dissociative branching ratios measured; for these small systems, the C-2(-) fragment was found magical. Data concerning electron capture in neutral-neutral collisions are extremely rare, especially at high velocity. Introduction of this measured process in the independent atom and electron (IAE) model allowed us to revisit and satisfactorily reproduce the so-far unexplained size evolution of single electron capture (SEC) cross sections in 2.6 au C-n(+)-He (n <= 10) collisions (Chabot et al 2006 J. Phys. B: At. Mol. Opt. Phys. 39 2593-603). IAE calculations for DEC cross sections and their comparison with experiment suggest a loss of electron in anionic C-n(-) species after the collision, competing with fragmentation and depending on the size

A 3D geometric approach to face detection and facial expression recognition

Face detection and facial expression recognition are research areas with important application possibilities. Although the two problems are usually dealt with different approaches, we show in this paper how the same recognition process can be used to recognize both a generic “class-face” in a given, possibly complex image, and a specific facial expression. The approach we propose is based on two steps. In the former we use alignment techniques in order to overlap the 3D representations of the main face components with the 2D image elements. In the latter we compare the candidate groups of localized components with a set of structural models, each of which representing a facial expression. Expressionindependent face detection is achieved using the same approach with a model built generalizing over a set of face examples with different expressions