6,066 research outputs found
Gravitomagnetism in superconductors and compact stars
There are three experimentally observed effects in rotating superconductors
that are so far unexplained. Some authors have tried to interpret such a
phenomena as possible new gravitational properties of coherent quantum systems:
in particular, they suggest that the gravitomagnetic field of that kind of
matter may be many orders of magnitude stronger than the one expected in the
standard theory. Here I show that this interpretation would be in conflict with
the common belief that neutron stars have neutrons in superfluid state and
protons in superconductive one.Comment: 9 pages, no figur
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Medical implantable devices for the controlled release of anti-TGF-beta1 in the repair of peripheral nerve injuries
The development of novel bioartificial nerve grafts which release soluble therapeutic agents, shows great promises guiding the extension of the injured axons and optimizing and improving the degree and specificity of neural outgrowth. The TGF-â family cytokines are polypeptides involved in pathogenesis of neuropathies during nerve lesion. In particular, studies carried out on TGF-â1 have demonstrated its key-role as a humoral stimulus in scar formation. The use of neutralising antibodies to this pro-fibrotic factor, incorporated and released by medical devices, could be potentially useful to get improved results in nerve repair. The aim of this study was to characterise the uptake and release of antibodies, structurally no different from the anti-TGFâ1 specific ones, by innovative constructs based on the use of biodegradable and biocompatible compounds with which to support and improve peripheral nerve repair
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Efficient Metadeliberation Auctions
Imagine a resource allocation scenario in which the interested parties can, at a cost, individually research ways of using the resource to be allocated, potentially increasing the value they would achieve from obtaining it. Each agent has a private model of its research process and obtains a private realization of its improvement in value, if any. From a social perspective it is optimal to coordinate research in a way that strikes the right tradeoff between value and cost, ultimately allocating the resource to one party- thus this is a problem of multi-agent metadeliberation. We provide a reduction of computing the optimal deliberation-allocation policy to computing Gittins indices in multi-anned bandit worlds, and apply a modification of the dynamic-VCG mechanism to yield truthful participation in an ex post equilibrium. Our mechanism achieves equilibrium implementation ofthe optimal policy even when agents have the capacity to deliberate about other agents' valuations, and thus addresses the problem of strategic deliberation.Engineering and Applied Science
On the time delay in binary systems
The aim of this paper is to study the time delay on electromagnetic signals
propagating across a binary stellar system. We focus on the antisymmetric
gravitomagnetic contribution due to the angular momentum of one of the stars of
the pair. Considering a pulsar as the source of the signals, the effect would
be manifest both in the arrival times of the pulses and in the frequency shift
of their Fourier spectra. We derive the appropriate formulas and we discuss the
influence of different configurations on the observability of gravitomagnetic
effects. We argue that the recently discovered PSR J0737-3039 binary system
does not permit the detection of the effects because of the large size of the
eclipsed region.Comment: 7 pages, 2 eps figures, RevTex, to appear in Physical Review
A post-Keplerian parameter to test gravito-magnetic effects in binary pulsar systems
We study the pulsar timing, focusing on the time delay induced by the
gravitational field of the binary systems. In particular, we study the
gravito-magnetic correction to the Shapiro time delay in terms of Keplerian and
post-Keplerian parameters, and we introduce a new post-Keplerian parameter
which is related to the intrinsic angular momentum of the stars. Furthermore,
we evaluate the magnitude of these effects for the binary pulsar systems known
so far. The expected magnitude is indeed small, but the effect is important per
se.Comment: 6 pages, RevTeX, 1 eps figure, accepted for publication in Physical
Review D; references adde
Gravitomagnetic time-varying effects on the motion of a test particle
We study the effects of a time-varying gravitomagnetic field on the motion of
test particles. Starting from recent results, we consider the gravitomagnetic
field of a source whose spin angular momentum has a linearly time-varying
magnitude. The acceleration due to such a time-varying gravitomagnetic field is
considered as a perturbation of the Newtonian motion, and we explicitly
evaluate the effects of this perturbation on the Keplerian elements of a closed
orbit. The theoretical predictions are compared with actual astronomical and
astrophysical scenarios, both in the solar system and in binary pulsars
systems, in order to evaluate the impact of these effects on real systems.Comment: 8 pages, RevTeX; revised to match the version accepted for
publication in General Relativity and Gravitatio
Targeting the Toll-like receptor/interleukin 1 receptor pathway in human diseases: rational design of MyD88 inhibitors
Toll-like receptor (TLR)/interleukin (IL) 1 receptor (IL-1R) play a fundamental role in the immune response. These receptors are distributed in various cellular compartments and recognize different components of pathogens. All TLR/IL-1Rs, with the exception of TLR3, interact with MyD88, an intracellular adapter protein that triggers a signaling cascade that culminates in the expression of inflammatory genes. Because aberrant activation of TLR/IL-1Rs can promote the onset of inflammatory or autoimmune diseases and malignancies, this pathway has attracted considerable interest as a potential therapeutic target. Given the central role of MyD88 in TLR/IL-1R signaling, we set out different strategies to develop drugs that can block its function. Structural and functional analysis of the MyD88 domains allowed us to identify crucial residues required for MyD88 homodimerization. Moreover, we developed small cell-permeable peptides and peptidomimetic agents that inhibit MyD88 homodimerization and function. Our results pave the way for the development of new therapeutic drugs for the inhibition of MyD88-dependent signaling
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