1,355 research outputs found

    Src homology 2 domain containing protein 5 (SH2D5) binds the breakpoint cluster region protein, BCR, and regulates levels of Rac1-GTP

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    SH2D5 is a mammalian-specific, uncharacterized adaptor-like protein that contains an N-terminal phosphotyrosine binding (PTB) domain and a C-terminal Src Homology 2 (SH2) domain. We show that SH2D5 is highly enriched in adult mouse brain, particularly in purkinjie cells in the cerebellum and the cornu ammonis of the hippocampus. Despite harboring two potential phosphotyrosine (pTyr) recognition domains, SH2D5 binds minimally to pTyr ligands, consistent with the absence of a conserved pTyr-binding arginine residue in the SH2 domain. Immunoprecipitation coupled to mass spectrometry (IP-MS) from cultured cells revealed a prominent association of SH2D5 with Breakpoint Cluster Region protein (BCR), a RacGAP that is also highly expressed in brain. This interaction occurred between the PTB domain of SH2D5 and an NxxF motif located within the N-terminal region of BCR. siRNA-mediated depletion of SH2D5 in a neuroblastoma cell line, B35, induced a cell rounding phenotype correlated with low levels of activated Rac1-GTP, suggesting that SH2D5 affects Rac1-GTP levels. Taken together, our data provide the first characterization of the SH2D5 signaling protein

    Preparation of hybrid organic-inorganic materials based on a di-ureasil matrix doped with lithium bis(trifluoromethanesulfonyl)imide

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    In this presentation we describe the preparation of solvent-free solid polymer electrolytes (SPEs) by the sol-gel route with the incorporation of controlled quantities of lithium bis(trifluoromethanesulfonyl) imide (LiTFSI) into the host matrix. The host framework of these xerogels, designated as di-ureasils and represented by d-U(900), contains oxyethylene oligomers with about 15 repeat units bonded at each end to a siliceous backbone through urea bridging links. Electrolytes were characterized by ionic conductivity measurements, cyclic voltammetry at a gold microelectrode and thermal analysis. The results obtained reveal that these hybrid materials are completely amorphous and exhibit appropriate electrochemical characteristics for a variety of applications.Fundação para a Ciência e a Tecnologia - POCI/QUI/59856/2004; POCTI/3/686; SFRH/BD/22707/2005

    Flow profoundly influences fibrin network structure: Implications for fibrin formation and clot stability in haemostasis

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    Dear Sirs, Haemostasis requires fibrinogen conversion to fibrin and formation of a stable fibrin network. Fibrin network properties, including fibre thickness, branchpoint density, fibre density, mechanical stability, porosity, and resistance to lysis can differentiate plasma clots of healthy individuals from those with haemostatic or thrombotic disorders. Plasma from patients with a bleeding history produces thick, minimally-branched fibres in coarse, deformable networks that are highly susceptible to lysis, whereas plasma from patients with a personal or family history of thrombosis produces thin, highly-branched fibres in impermeable, rigid networks that are relatively resistant to fibrinolysi

    Use of variability in national and regional data to estimate the prevalence of lymphangioleiomyomatosis

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    Background: Understanding the true prevalence of lymphangioleiomyomatosis (LAM) is important in estimating disease burden and targeting specific interventions. As with all rare diseases, obtaining reliable epidemiological data is difficult and requires innovative approaches. Aim: To determine the prevalence and incidence of LAM using data from patient organizations in seven countries, and to use the extent to which the prevalence of LAM varies regionally and nationally to determine whether prevalence estimates are related to health-care provision. Methods: Numbers of women with LAM were obtained from patient groups and national databases from seven countries (n = 1001). Prevalence was calculated for regions within countries using female population figures from census data. Incidence estimates were calculated for the USA, UK and Switzerland. Regional variation in prevalence and changes in incidence over time were analysed using Poisson regression and linear regression. Results: Prevalence of LAM in the seven countries ranged from 3.4 to 7.8/million women with significant variation, both between countries and between states in the USA. This variation did not relate to the number of pulmonary specialists in the region nor the percentage of population with health insurance, but suggests a large number of patients remain undiagnosed. The incidence of LAM from 2004 to 2008 ranged from 0.23 to 0.31/million women/per year in the USA, UK and Switzerland. Conclusions: Using this method, we have found that the prevalence of LAM is higher than that previously recorded and that many patients with LAM are undiagnose

    Emotional valence and arousal affect reading in an interactive way: neuroimaging evidence for an approach-withdrawal framework

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    A growing body of literature shows that the emotional content of verbal material affects reading, wherein emotional words are given processing priority compared to neutral words. Human emotions can be conceptualised within a two-dimensional model comprised of emotional valence and arousal (intensity). These variables are at least in part distinct, but recent studies report interactive effects during implicit emotion processing and relate these to stimulus-evoked approach-withdrawal tendencies. The aim of the present study was to explore how valence and arousal interact at the neural level, during implicit emotion word processing. The emotional attributes of written word stimuli were orthogonally manipulated based on behavioural ratings from a corpus of emotion words. Stimuli were presented during an fMRI experiment while 16 participants performed a lexical decision task, which did not require explicit evaluation of a word's emotional content. Results showed greater neural activation within right insular cortex in response to stimuli evoking conflicting approach-withdrawal tendencies (i.e., positive high-arousal and negative low-arousal words) compared to stimuli evoking congruent approach vs. withdrawal tendencies (i.e., positive low-arousal and negative high-arousal words). Further, a significant cluster of activation in the left extra-striate cortex was found in response to emotional than neutral words, suggesting enhanced perceptual processing of emotionally salient stimuli. These findings support an interactive two-dimensional approach to the study of emotion word recognition and suggest that the integration of valence and arousal dimensions recruits a brain region associated with interoception, emotional awareness and sympathetic functions

    Quantum Coherence in a Single Ion due to strong Excitation of a metastable Transition

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    We consider pump-probe spectroscopy of a single ion with a highly metastable (probe) clock transition which is monitored by using the quantum jump technique. For a weak clock laser we obtain the well known Autler-Townes splitting. For stronger powers of the clock laser we demonstrate the transition to a new regime. The two regimes are distinguished by the transition of two complex eigenvalues to purely imaginary ones which can be very different in magnitude. The transition is controlled by the power of the clock laser. For pump on resonance we present simple analytical expressions for various linewidths and line positions.Comment: 6 figures. accepted for publication in PR

    Connecting LHC, ILC, and Quintessence

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    If the cold dark matter consists of weakly interacting massive particles (WIMPs), anticipated measurements of the WIMP properties at the Large Hadron Collider (LHC) and the International Linear Collider (ILC) will provide an unprecedented experimental probe of cosmology at temperatures of order 1 GeV. It is worth emphasizing that the expected outcome of these tests may or may not be consistent with the picture of standard cosmology. For example, in kination-dominated quintessence models of dark energy, the dark matter relic abundance can be significantly enhanced compared to that obtained from freeze out in a radiation-dominated universe. Collider measurements then will simultaneously probe both dark matter and dark energy. In this article, we investigate the precision to which the LHC and ILC can determine the dark matter and dark energy parameters under those circumstances. We use an illustrative set of four benchmark points in minimal supergravity in analogy with the four LCC benchmark points. The precision achievable together at the LHC and ILC is sufficient to discover kination-dominated quintessence, under the assumption that the WIMPs are the only dark matter component. The LHC and ILC can thus play important roles as alternative probes of both dark matter and dark energy.Comment: 38 pages, 9 figure

    Likelihood Functions for Supersymmetric Observables in Frequentist Analyses of the CMSSM and NUHM1

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    On the basis of frequentist analyses of experimental constraints from electroweak precision data, g-2, B physics and cosmological data, we investigate the parameters of the constrained MSSM (CMSSM) with universal soft supersymmetry-breaking mass parameters, and a model with common non-universal Higgs masses (NUHM1). We present chi^2 likelihood functions for the masses of supersymmetric particles and Higgs bosons, as well as b to s gamma, b to mu mu and the spin-independent dark matter scattering cross section. In the CMSSM we find preferences for sparticle masses that are relatively light. In the NUHM1 the best-fit values for many sparticle masses are even slightly smaller, but with greater uncertainties. The likelihood functions for most sparticle masses are cut off sharply at small masses, in particular by the LEP Higgs mass constraint. Both in the CMSSM and the NUHM1, the coannihilation region is favoured over the focus-point region at about the 3-sigma level, largely but not exclusively because of g-2. Many sparticle masses are highly correlated in both the CMSSM and NUHM1, and most of the regions preferred at the 95% C.L. are accessible to early LHC running. Some slepton and chargino/neutralino masses should be in reach at the ILC. The masses of the heavier Higgs bosons should be accessible at the LHC and the ILC in portions of the preferred regions in the (M_A, tan beta) plane. In the CMSSM, the likelihood function for b to mu mu is peaked close to the Standard Model value, but much larger values are possible in the NUHM1. We find that values of the DM cross section > 10^{-10} pb are preferred in both the CMSSM and the NUHM1. We study the effects of dropping the g-2, b to s gamma, relic density and M_h constraints.Comment: 34 pages, 24 figure

    Production and Decay of D_1(2420)^0 and D_2^*(2460)^0

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    We have investigated D+π−D^{+}\pi^{-} and D∗+π−D^{*+}\pi^{-} final states and observed the two established L=1L=1 charmed mesons, the D1(2420)0D_1(2420)^0 with mass 2421−2−2+1+22421^{+1+2}_{-2-2} MeV/c2^{2} and width 20−5−3+6+320^{+6+3}_{-5-3} MeV/c2^{2} and the D2∗(2460)0D_2^*(2460)^0 with mass 2465±3±32465 \pm 3 \pm 3 MeV/c2^{2} and width 28−7−6+8+628^{+8+6}_{-7-6} MeV/c2^{2}. Properties of these final states, including their decay angular distributions and spin-parity assignments, have been studied. We identify these two mesons as the jlight=3/2j_{light}=3/2 doublet predicted by HQET. We also obtain constraints on {\footnotesize ΓS/(ΓS+ΓD)\Gamma_S/(\Gamma_S + \Gamma_D)} as a function of the cosine of the relative phase of the two amplitudes in the D1(2420)0D_1(2420)^0 decay.Comment: 15 pages in REVTEX format. hardcopies with figures can be obtained by sending mail to: [email protected]
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