26 research outputs found

    Scalar-Tensor Models of Normal and Phantom Dark Energy

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    We consider the viability of dark energy (DE) models in the framework of the scalar-tensor theory of gravity, including the possibility to have a phantom DE at small redshifts zz as admitted by supernova luminosity-distance data. For small zz, the generic solution for these models is constructed in the form of a power series in zz without any approximation. Necessary constraints for DE to be phantom today and to cross the phantom divide line p=−ρp=-\rho at small zz are presented. Considering the Solar System constraints, we find for the post-Newtonian parameters that ÎłPN<1\gamma_{PN}<1 and ÎłPN,0≈1\gamma_{PN,0}\approx 1 for the model to be viable, and ÎČPN,0>1\beta_{PN,0}>1 (but very close to 1) if the model has a significantly phantom DE today. However, prospects to establish the phantom behaviour of DE are much better with cosmological data than with Solar System experiments. Earlier obtained results for a Λ\Lambda-dominated universe with the vanishing scalar field potential are extended to a more general DE equation of state confirming that the cosmological evolution of these models rule them out. Models of currently fantom DE which are viable for small zz can be easily constructed with a constant potential; however, they generically become singular at some higher zz. With a growing potential, viable models exist up to an arbitrary high redshift.Comment: 30 pages, 4 figures; Matches the published version containing an expanded discussion of various point

    Numbers in the Blind's “Eye”

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    Background: Although lacking visual experience with numerosities, recent evidence shows that the blind perform similarly to sighted persons on numerical comparison or parity judgement tasks. In particular, on tasks presented in the auditory modality, the blind surprisingly show the same effect that appears in sighted persons, demonstrating that numbers are represented through a spatial code, i.e. the Spatial-Numerical Association of Response Codes (SNARC) effect. But, if this is the case, how is this numerical spatial representation processed in the brain of the blind? Principal Findings: Here we report that, although blind and sighted people have similarly organized numerical representations, the attentional shifts generated by numbers have different electrophysiological correlates (sensorial N100 in the sighted and cognitive P300 in the blind). Conclusions: These results highlight possible differences in the use of spatial representations acquired through modalities other than vision in the blind population

    M402, a Novel Heparan Sulfate Mimetic, Targets Multiple Pathways Implicated in Tumor Progression and Metastasis

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    Heparan sulfate proteoglycans (HSPGs) play a key role in shaping the tumor microenvironment by presenting growth factors, cytokines, and other soluble factors that are critical for host cell recruitment and activation, as well as promoting tumor progression, metastasis, and survival. M402 is a rationally engineered, non-cytotoxic heparan sulfate (HS) mimetic, designed to inhibit multiple factors implicated in tumor-host cell interactions, including VEGF, FGF2, SDF-1α, P-selectin, and heparanase. A single s.c. dose of M402 effectively inhibited seeding of B16F10 murine melanoma cells to the lung in an experimental metastasis model. Fluorescent-labeled M402 demonstrated selective accumulation in the primary tumor. Immunohistological analyses of the primary tumor revealed a decrease in microvessel density in M402 treated animals, suggesting anti-angiogenesis to be one of the mechanisms involved in-vivo. M402 treatment also normalized circulating levels of myeloid derived suppressor cells in tumor bearing mice. Chronic administration of M402, alone or in combination with cisplatin or docetaxel, inhibited spontaneous metastasis and prolonged survival in an orthotopic 4T1 murine mammary carcinoma model. These data demonstrate that modulating HSPG biology represents a novel approach to target multiple factors involved in tumor progression and metastasis

    Bis-14-membered ring diketal diamines: Synthesis and evaluation of their anti-HIV and anti-tumoral activities

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    Chiral and achiral macrocyclic bis-diketal diamines, analogs of bicyclam AMD 3100, were synthesized in three steps from the previously obtained 14-membered ring diketal dilactams. Their monoreduction with lithium aluminium hydride gave the corresponding diketal aminolactams. Coupling these with dibromo-pxylene led to xylyl dimer compounds. A second reduction step yielded the expected bis-diketal diamines in the methyl and unsubstituted series. Biological tests on the unreduced and reduced dimers showed both weak anti-HIV and anti-proliferative activities for the bis-diphenyl diketal aminolactam 13b, with a mode of action probably different from that of AMD 3100. 1

    Case Report: HĂ©mangiome vertĂ©brale gĂ©ant rĂ©vĂ©lĂ© par un traumatisme lombaire: Ă  propos d’un cas

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    L'hĂ©mangiome vertebral est une tumeur bĂ©nigne frĂ©quente, c'est une lĂ©sion bĂ©nigne habituellement  asymptomatique. Les formes Ă©volutives rĂ©sponsables de compression mĂ©dullaire sont beaucoup plus rares, une surveillance clinique et radiologique est conseillĂ©. Nous mettons en exergue Ă  travers ce cas revelĂ© par des signes de compression mĂ©dullaire suite Ă  une chute, l'intĂ©rĂȘt de l'imagerie en coupes dans le diagnostic positif ; pour dĂ©celer les formes compliquĂ©es, et pour orienter l'attitude thĂ©rapeutique. Les formes  neurologiques nĂ©cessitent une prise en charge neurochirurgicale.Key words: HĂ©mangiome vertĂ©brale, compression mĂ©dullaire, traumatisme lombair
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