1,186 research outputs found
Red alert: labile heme is an alarmin
This publication hasn't any creative commons license associated.This deposit is composed by the main article, and it hasn't any supplementary materials associated. There is no public supplementary material available.The deposited article is a pre-print version.Alarmins are a heterogeneous group of endogenous molecules that signal cellular damage when sensed extracellularly. Heme is an endogenous molecule that acts as a prosthetic group of hemoproteins, such as hemoglobin and myoglobin. When released from damaged red blood cells or muscle cells, oxidized hemoglobin and myoglobin release their prosthetic heme groups, respectively. This generates labile heme, which is sensed by pattern recognition receptors (PRR) expressed by innate immune cells and possibly regulatory T cells (TREG). The ensuing adaptive response, which alerts for the occurrence of red blood cell or muscle cell damage, regulates the pathologic outcome of hemolysis or rhabdomyolysis, respectively. In conclusion, we propose that labile heme is an alarmin.Fundação para a Ciência e Tecnologia grants: (PTDC/SAU TOX/116627/2010, HMSP-ICT/0022/2010, RECI/IMI-IMU/0038/2012); Fundação de Amparo a Pesquisa do Estado do Rio de Janeiro; Conselho Nacional de Pesquisa, INCTDengue, Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior.info:eu-repo/semantics/publishedVersio
Paradise revealed: first-class science rocked by the sound of the waves
Univ São Paulo, Inst Ciencias Biomed, Dept Imunol, BR-05508900 São Paulo, BrazilInst Nacl Ciencia & Tecnol, Inst Invest Imunol, São Paulo, BrazilUniversidade Federal de São Paulo, Dept Ciencias Biol, Diaderna, SP, BrazilFundacao Oswaldo Cruz, Inst Oswaldo Cruz, Lab Imunofarmacol, Rio de Janeiro, BrazilUniv São Paulo, Fac Med, BR-05508900 São Paulo, BrazilInst Nacl Canc, Div Biol Celular, Rio de Janeiro, BrazilUniversidade Federal de São Paulo, Dept Ciencias Biol, Diaderna, SP, BrazilWeb of Scienc
Particle motion and gravitational lensing in the metric of a dilaton black hole in a de Sitter universe
We consider the metric exterior to a charged dilaton black hole in a de
Sitter universe. We study the motion of a test particle in this metric.
Conserved quantities are identified and the Hamilton-Jacobi method is employed
for the solutions of the equations of motion. At large distances from the black
hole the Hubble expansion of the universe modifies the effective potential such
that bound orbits could exist up to an upper limit of the angular momentum per
mass for the orbiting test particle. We then study the phenomenon of strong
field gravitational lensing by these black holes by extending the standard
formalism of strong lensing to the non-asymptotically flat dilaton-de Sitter
metric. Expressions for the various lensing quantities are obtained in terms of
the metric coefficients.Comment: 8 pages, RevTex, 1 eps figures; discussion improved; typos corrected;
references adde
Strong Gravitational Lensing in a Charged Squashed Kaluza- Klein Black hole
In this paper we investigate the strong gravitational lensing in a charged
squashed Kaluza-Klein black hole. We suppose that the supermassive black hole
in the galaxy center can be considered by a charged squashed Kaluza-Klein black
hole and then we study the strong gravitational lensing theory and estimate the
numerical values for parameters and observables of it. We explore the effects
of the scale of extra dimension and the charge of black hole
on these parameters and observables.Comment: 17 pages, 10 figure
Lorentz-violation and cosmological perturbations: a toy brane-world model
We study possible effects of Lorentz-violation on the generation of
cosmological perturbations at inflation by introducing a simple inflating
five-dimensional brane-world setup with violation of four-dimensional
Lorentz-invariance at an energy scale . We consider massless scalar field,
meant to mimic perturbations of inflaton and/or gravitational field, in this
background. At three-momenta below , there exists a zero mode localized on
the brane, whose behaviour coincides with that in four-dimensional theory. On
the contrary, at three-momenta above , the localized mode is absent and
physics is entirely five-dimensional. As three-momenta get redshifted, more
modes get localized on the brane, the phenomenon analogous to ``mode
generation''. We find that for , where is the inflationary Hubble
scale, the spectrum of perturbations coincides with that in four-dimensional
theory. For and time-dependent bulk parameters, the spectrum deviates,
possibly strongly, from the flat spectrum even for pure de Sitter inflation.Comment: 5 figures, iopart, minor changes, appendix adde
Gravitational Lensing by Black Holes
We review the theoretical aspects of gravitational lensing by black holes,
and discuss the perspectives for realistic observations. We will first treat
lensing by spherically symmetric black holes, in which the formation of
infinite sequences of higher order images emerges in the clearest way. We will
then consider the effects of the spin of the black hole, with the formation of
giant higher order caustics and multiple images. Finally, we will consider the
perspectives for observations of black hole lensing, from the detection of
secondary images of stellar sources and spots on the accretion disk to the
interpretation of iron K-lines and direct imaging of the shadow of the black
hole.Comment: Invited article for the GRG special issue on lensing (P. Jetzer, Y.
Mellier and V. Perlick Eds.). 31 pages, 12 figure
Gravitational lensing by stars with angular momentum
Gravitational lensing by spinning stars, approximated as homogeneous spheres,
is discussed in the weak field limit. Dragging of inertial frames, induced by
angular momentum of the deflector, breaks spherical symmetry. I examine how the
gravito-magnetic field affects image positions, caustics and critical curves.
Distortion in microlensing-induced light curves is also considered.Comment: 9 pages, 9 figures; to appear in MNRA
Tracking Curvaton(s)?
The ratio of the curvaton energy density to that of the dominant component of
the background sources may be constant during a significant period in the
evolution of the Universe. The possibility of having tracking curvatons, whose
decay occurs prior to the nucleosynthesis epoch, is studied. It is argued that
the tracking curvaton dynamics is disfavoured since the value of the curvature
perturbations prior to curvaton decay is smaller than the value required by
observations. It is also argued, in a related context, that the minimal
inflationary curvature scale compatible with the curvaton paradigm may be
lowered in the case of low-scale quintessential inflation.Comment: 20 pages, 4figure
Black holes from high-energy beam--beam collisions
Using a recent technique, proposed by Eardley and Giddings, we extend their
results to the high-energy collision of two beams of massless particles, i.e.
of two finite-front shock waves. Closed (marginally) trapped surfaces can be
determined analytically in several cases even for collisions at non-vanishing
impact parameter in D\ge 4 space-time dimensions. We are able to confirm and
extend earlier conjectures by Yurtsever, and to deal with arbitrary
axisymmetric profiles, including an amusing case of ``fractal'' beams. We
finally discuss some implications of our results in high-energy experiments and
in cosmology.Comment: 17 pages Revtex, 1 figure, references adde
The Primordial Perturbation Spectrum from Various Expanding and Contracting Phases
In this paper, focusing on the case of single scalar field, we discuss
various expanding and contracting phases generating primordial perturbations,
and study the relation between the primordial perturbation spectrum from these
phases and the parameter w of state equation in details. Furthermore, we offer
an interesting classification for the primordial perturbation spectrum from
various phases, which may have important implications for building an early
universe scenario embedded in possible high energy theories.Comment: 5 pages, 3 eps figure
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