Evidence that the degree of band 3 phosphorylation modulates human erythrocytes nitric oxide efflux – in vitro model of hyperfibrinogenemia

© 2011 – IOS Press and the authors. All rights reservedRecent evidence has shown that plasma fibrinogen, a major cardiovascular risk factor, interacts with the erythrocyte membrane and acts to influence blood flow via erythrocyte nitric oxide (NO) modulation. In the present pioneer in-vitro study, whole blood samples were harvested from healthy subjects and aliquots were incubated in the absence (control aliquots) and presence of fibrinogen at different degrees of band 3 phosphorylation, and the levels of NO, nitrite, nitrate and S-nitroglutathione (GSNO) were determined. Hyperfibrinogenemia interferes with erythrocyte NO mobilization without changing its efflux in a way that seems to be dependent of the degree of band 3 phosphorylation. In presence of higher fibrinogen concentrations the NO efflux is reinforced when band 3 is phosphorylated (p < 0.001). Higher levels of nitrite, nitrate and GSNO were documented (p < 0.05). However, the mechanisms by which fibrinogen signalling modulates erythrocyte function remain to be clarified and are currently under study. These conditions may be considered an approach to be followed in blood storage for transfusions.This study was supported by grants from the FCT - Fundação para a Ciência e a Tecnologia (project reference PTDC/SAU-OSM/73449/2006

The pseudoscalar meson electromagnetic form factor at high Q2 from full lattice QCD

We give an accurate determination of the vector (electromagnetic) form factor, F(Q^2), for a light pseudoscalar meson up to squared momentum transfer Q^2 values of 6 GeV^2 for the first time from full lattice QCD, including u, d, s and c quarks in the sea at multiple values of the lattice spacing. Our results show good control of lattice discretisation and sea quark mass effects. We study a pseudoscalar meson made of valence s quarks but the qualitative picture obtained applies also to the \pi meson, relevant to upcoming experiments at Jefferson Lab. We find that Q^2F(Q^2) becomes flat in the region between Q^2 of 2 GeV^2 and 6 GeV^2, with a value well above that of the asymptotic perturbative QCD expectation, but well below that of the vector-meson dominance pole form appropriate to low Q^2 values. Our calculations show that we can reach higher Q^2 values in future to shed further light on where the perturbative QCD result emerges

Topological Defects in Contracting Universes

We study the behaviour and consequences of cosmic string networks in contracting universes. They approximately behave during the collapse phase as a radiation fluids. Scaling solutions describing this are derived and tested against high-resolution numerical simulations. A string network in a contracting universe, together with the gravitational radiation it generates, can affect the dynamics of the universe both locally and globally, and be an important source of radiation, entropy and inhomogeneity. We discuss possible implications for bouncing and cyclic models.Comment: Shorter version of astro-ph/0206287. To appear in Phys. Rev. Let

Past-present discontinuity in ecological change and marine governance: an integrated narrative approach to artisanal fishing

Today artisanal fishers working in Natura 2000 coastal protected sites face two major types of change: in marine resources, and the governance of their professions. Such transformations affect fishers’ livelihoods, identities and traditions, yet little is known about how these professionals elaborate on these changes – i.e., as continuities or discontinuities - in the narratives they produce as a group. Interviews and focus-groups with artisanal fishers and shellfish harvesters (n=36) from the Portuguese Southwest coast were subjected to a two-step analysis. First, a textual analysis with Iramuteq helped select the themes directly related to marine resources and governance. Second, three main narratives - on algae, barnacles and fish - were reconstructed. These were then explored regarding: (1) narrative formats (stability, regressive, progressive, mixed); (2) whether/how these formats elaborated changes as continuities or discontinuities; (3) the roles attributed to Self and Others, and whether and how these legitimized the laws, opening avenues for change; and (4) whether narratives were unified or fragmented. This study illustrates how transformations are presented through various combinations of narrative formats, sometimes mobilized to resist and other times to legitimate legal institutional change. It shows how institutional change can be integrated into local narratives as a positive contribution through a process that implies re-constructing the collective identity and local traditions. Through a narrative approach, this paper offers an integrated examination of fishers’ concerns towards their professions and the laws regulating them, and provides useful insight into how and when marine governance is more/less likely to be legitimized.info:eu-repo/semantics/acceptedVersio