Pressure-induced densification of vitreous silica: insight from elastic properties

\textit{In situ} high-pressure Brillouin light scattering experiments along loading-unloading paths are used to investigate the compressibility of vitreous silica. An accurate equation of state is obtained below \SI{9}{GPa} using sound velocities corrected for dispersion. Conversely, huge inelastic effects are observed in the range \SIrange{10}{60}{GPa}, unveiling the reversible transformation from the fourfold-coordinated structure to the sixfold one. We find that the associated density changes fully correlate with the average Si coordination number. Decompression curves from above \SI{20}{GPa} reveal abrupt backward coordination changes around \SIrange{10}{15}{GPa} and significant hysteresis. Further, contrary to common wisdom, the residual densification of recovered silica samples can be figured out from the pressure cycles.Comment: 5 pages, 4 figures, revised versio

The SWEET-HOME Project: Audio Technology in Smart Homes to improve Well-being and Reliance

International audienceThe SWEET-HOME project aims at providing audio-based interaction technology that lets the user have full control over their home environment, at detecting distress situations and at easing the social inclusion of the elderly and frail population. This paper presents an overview of the project focusing on the implemented techniques for speech and sound recognition as context-aware decision making with uncertainty. A user experiment in a smart home demonstrates the interest of this audio-based technology

The cleaved FAS ligand activates the Na+/H+ exchanger NHE1 through Akt/ROCK1 to stimulate cell motility

International audienceTransmembrane CD95L (Fas ligand) can be cleaved to release a promigratory soluble ligand, cl-CD95L, which can contribute to chronic inflammation and cancer cell dissemination. The motility signaling pathway elicited by cl-CD95L remains poorly defined. Here, we show that in the presence of cl-CD95L, CD95 activates the Akt and RhoA signaling pathways, which together orchestrate an allosteric activation of the Na+/H+ exchanger NHE1. Pharmacologic inhibition of Akt or ROCK1 independently blocks the cl-CD95L-induced migration. Confirming these pharmacologic data, disruption of the Akt and ROCK1 phosphorylation sites on NHE1 decreases cell migration in cells exposed to cl-CD95L. Together, these findings demonstrate that NHE1 is a novel molecular actor in the CD95 signaling pathway that drives the cl-CD95L-induced cell migration through both the Akt and RhoA signaling pathways

Mn2+ Complexes with Pyclen-Based Derivatives as Contrast Agents for Magnetic Resonance Imaging: Synthesis and Relaxometry Characterization

Magnetic resonance imaging (MRI) has a leading place in medicine as an imaging tool of high resolution for anatomical studies and diagnosis of diseases, in particular for soft tissues that cannot be accessible by other modalities. Many research works are thus focused on improving the images obtained with MRI. This technique has indeed poor sensitivity, which can be compensated by using a contrast agent (CA). Today, the clinically approved CAs on market are solely based on gadolinium complexes that may induce nephrogenic systemic fibrosis for patients with kidney failure, whereas more recent studies on healthy rats also showed Gd retention in the brain. Consequently, researchers try to elaborate other types of safer MRI CAs like manganese-based complexes. In this context, the synthesis of Mn2+ complexes of four 12-membered pyridine-containing macrocyclic ligands based on the pyclen core was accomplished and described herein. Then, the properties of these Mn(II) complexes were studied by two relaxometric methods, 17O NMR spectroscopy and 1H NMR dispersion profiles. The time of residence (τM) and the number of water molecules (q) present in the inner sphere of coordination were determined by these two experiments. The efficacy of the pyclen-based Mn(II) complexes as MRI CAs was evaluated by proton relaxometry at a magnetic field intensity of 1.41 T near those of most medical MRI scanners (1.5 T). Both the 17O NMR and the nuclear magnetic relaxation dispersion profiles indicated that the four hexadentate ligands prepared herein left one vacant coordination site to accommodate one water molecule, rapidly exchanging, in around 6 ns. Furthermore, it has been shown that the presence of an additional amide bond formed when the paramagnetic complex is conjugated to a molecule of interest does not alter the inner sphere of coordination of Mn, which remains monohydrated. These complexes exhibit r1 relaxivities, large enough to be used as clinical MRI CAs (1.7–3.4 mM–1·s–1, at 1.41 T and 37 °C)

Origin of the high elevated Pyrenean peneplain

Peneplanation of mountain ranges is generally considered the result of long-term erosional processes that smooth relief and lower elevation near sea level. Therefore peneplain remnants at high elevation in mountain ranges are used to infer posttectonic surface uplift. Such an interpretation has been proposed for the Pyrenees where high-elevation, low-relief erosional surfaces rose up to more than 2000 m. Because the Pyrenean foreland basins are filled with very thick continental deposits, which have buried the early jagged landscape, we challenge this hypothesis by pointing out that relief applanation does not necessarily require elevation lowering. We propose an alternative interpretation in which piedmont aggradation of detrital sediment that comes from erosion of the high chain induces the rise of the base level of the range, therefore reducing strongly the erosive efficiency of the drainage system and resulting in the progressive smoothing of the relief. Such a process allows a high-elevation, low-relief erosional surface to develop at the scale of the range. In the Pyrenees, occurrence of high-elevation, low-relief erosional surface remnants does not imply a posttectonic uplift, but is instead due to the dissection of the initial Miocene high-elevation, low-relief surface by the recent drainage system, the erosive activity of which has been enhanced by global climate change from the late Pliocene onward

The Naturally Processed CD95L Elicits a c-Yes/Calcium/PI3K-Driven Cell Migration Pathway

Patients affected by chronic inflammatory disorders display high amounts of soluble CD95L. This homotrimeric ligand arises from the cleavage by metalloproteases of its membrane-bound counterpart, a strong apoptotic inducer. In contrast, the naturally processed CD95L is viewed as an apoptotic antagonist competing with its membrane counterpart for binding to CD95. Recent reports pinpointed that activation of CD95 may attract myeloid and tumoral cells, which display resistance to the CD95-mediated apoptotic signal. However, all these studies were performed using chimeric CD95Ls (oligomerized forms), which behave as the membrane-bound ligand and not as the naturally processed CD95L. Herein, we examine the biological effects of the metalloprotease-cleaved CD95L on CD95-sensitive activated T-lymphocytes. We demonstrate that cleaved CD95L (cl-CD95L), found increased in sera of systemic lupus erythematosus (SLE) patients as compared to that of healthy individuals, promotes the formation of migrating pseudopods at the leading edge of which the death receptor CD95 is capped (confocal microscopy). Using different migration assays (wound healing/Boyden Chamber/endothelial transmigration), we uncover that cl-CD95L promotes cell migration through a c-yes/Ca2+/PI3K-driven signaling pathway, which relies on the formation of a CD95-containing complex designated the MISC for Motility-Inducing Signaling Complex. These findings revisit the role of the metalloprotease-cleaved CD95L and emphasize that the increase in cl-CD95L observed in patients affected by chronic inflammatory disorders may fuel the local or systemic tissue damage by promoting tissue-filtration of immune cells

Photography-based taxonomy is inadequate, unnecessary, and potentially harmful for biological sciences

The question whether taxonomic descriptions naming new animal species without type specimen(s) deposited in collections should be accepted for publication by scientific journals and allowed by the Code has already been discussed in Zootaxa (Dubois & Nemésio 2007; Donegan 2008, 2009; Nemésio 2009a–b; Dubois 2009; Gentile & Snell 2009; Minelli 2009; Cianferoni & Bartolozzi 2016; Amorim et al. 2016). This question was again raised in a letter supported by 35 signatories published in the journal Nature (Pape et al. 2016) on 15 September 2016. On 25 September 2016, the following rebuttal (strictly limited to 300 words as per the editorial rules of Nature) was submitted to Nature, which on 18 October 2016 refused to publish it. As we think this problem is a very important one for zoological taxonomy, this text is published here exactly as submitted to Nature, followed by the list of the 493 taxonomists and collection-based researchers who signed it in the short time span from 20 September to 6 October 2016

The CD95 signaling pathway: To not die and fly.

International audienceOur recent findings indicate that cells exposed to transmembrane (m-CD95L) or metalloprotease-cleaved CD95L (cl-CD95L) undergo a localized Ca(2+)entry that not only inhibits the initial steps of the CD95-mediated apoptotic signal but also promotes cell motility. Based on recent findings published on the non-apoptotic signals induced by CD95, we discuss how m-CD95L and cl-CD95L diverging by their stoichiometry could both contribute to the immune response by first recruiting activated T lymphocytes in the inflamed area and later by eliminating infected and transformed cells

Solid Carbon Produced in an Inductively Coupled Plasma Torch with a Titan Like Atmosphere

International audienceSolid carbon is deposited on the surfaces of an inductively coupled plasma torch operating with a Titan like atmosphere plasma gas. The frame of the initial research is the study of the radiative properties of plasma encountered around a spacecraft during its hypersonic entry in upper layers of planetary atmosphere. Deposition of carbon is observed not only on the quartz tube outside the inductor but also on the ceramic protection of the torch injector. Carbon exhibits two types of morphology more or less dense and it is analyzed by various analytic devices as MEB, SEM, TEM, EDS and Raman spectroscopy. The gathered carbon powder shows the presence of nanostructured particles