242 research outputs found
Une nouvelle activitĂ© enzymatique au niveau des lutoĂŻdes du latex d'Hevea brasiliensis MĂŒll. Arg. : l'ATP-AMP-phosphotransfĂ©rase
Minimal subtraction and the Callan-Symanzik equation
The usual proof of renormalizability using the Callan-Symanzik equation makes
explicit use of normalization conditions. It is shown that demanding that the
renormalization group functions take the form required for minimal subtraction
allows one to prove renormalizability using the Callan-Symanzik equation,
without imposing normalization conditions. Scalar field theory and quantum
electrodynamics are treated.Comment: 6 pages, plain Te
Coherent frequency conversion in a superconducting artificial atom with two internal degrees of freedom
By adding a large inductance in a dc-SQUID phase qubit loop, one decouples
the junctions' dynamics and creates a superconducting artificial atom with two
internal degrees of freedom. In addition to the usual symmetric plasma mode
({\it s}-mode) which gives rise to the phase qubit, an anti-symmetric mode
({\it a}-mode) appears. These two modes can be described by two anharmonic
oscillators with eigenstates and for the {\it s}
and {\it a}-mode, respectively. We show that a strong nonlinear coupling
between the modes leads to a large energy splitting between states
and . Finally, coherent frequency
conversion is observed via free oscillations between the states
and
Conductance oscillations in strongly correlated fractional quantum Hall line junctions
We present a detailed theory of transport through line junctions formed by
counterpropagating single-branch fractional-quantum-Hall edge channels having
different filling factors. Intriguing transport properties are exhibited when
strong Coulomb interactions between electrons from the two edges are present.
Such strongly correlated line junctions can be classified according to the
value of an effective line-junction filling factor n that is the inverse of an
even integer. Interactions turn out to affect transport most importantly for
n=1/2 and n=1/4. A particularly interesting case is n=1/4 corresponding to,
e.g., a junction of edge channels having filling factor 1 and 1/5,
respectively. We predict its differential tunneling conductance to oscillate as
a function of voltage. This behavior directly reflects the existence of novel
Majorana-fermion quasiparticle excitations in this type of line junction.
Experimental accessibility of such systems in current cleaved-edge overgrown
samples enables direct testing of our theoretical predictions.Comment: 2 figures, 10 pages, RevTex4, v2: added second figure for clarit
Subconjunctival Injection of XG-102, a c-Jun N-Terminal Kinase Inhibitor Peptide, in the Treatment of Endotoxin-Induced Uveitis in Rats.
Abstract Purpose: XG-102, a TAT-coupled dextrogyre peptide inhibiting the c-Jun N-terminal kinase, was shown efficient in the treatment of experimental uveitis. Preclinical studies are now performed to determine optimal XG-102 dose and route of administration in endotoxin-induced uveitis (EIU) in rats with the purpose of clinical study design.
METHODS: EIU was induced in Lewis rats by lipopolysaccharides (LPS) injection. XG-102 was administered at the time of LPS challenge by intravenous (IV; 3.2, 35 or 355âÎŒg/injection), intravitreal (IVT; 0.08, 0.2 or 2.2âÎŒg/eye), or subconjunctival (SCJ; 0.2, 1.8 or 22âÎŒg/eye) routes. Controls received either the vehicle (saline) or dexamethasone phosphate injections. Efficacy was assessed by clinical scoring, infiltrating cells count, and expression of inflammatory mediators [inducible nitric oxide synthase (iNOS), cytokine-induced neutrophil chemoattractant-1 (CINC-1)]. The effect of XG-102 on phosphorylation of c-Jun was evaluated by Western blot.
RESULTS: XG-102 demonstrated a dose-dependent anti-inflammatory effect in EIU after IV and SCJ administrations. Respective doses of 35 and 1.8âÎŒg were efficient as compared with the vehicle-injected controls, but only the highest doses, respectively 355 and 22âÎŒg, were as efficient as dexamethasone phosphate. After IVT injections, the anti-inflammatory effect of XG-102 was clinically evaluated similar to the corticoid's effect with all the tested doses. Regardless of the administration route, the lowest efficient doses of XG-102 significantly decreased the ration of phospho c-Jun/total c-Jun, reduced cells infiltration in the treated eyes, and significantly downregulated iNOS and CINC-1 expression in the retina.
CONCLUSION: These results confirm that XG-102 peptide has potential for treating intraocular inflammation. SCJ injection appears as a good compromise to provide a therapeutic effect while limiting side effects
Electronic structure and the minimum conductance of a graphene layer on SiO2 from density-functional methods.
The effect of the SiO substrate on a graphene film is investigated using
realistic but computationally convenient energy-optimized models of the
substrate supporting a layer of graphene. The electronic bands are calculated
using density-functional methods for several model substrates. This provides an
estimate of the substrate-charge effects on the behaviour of the bands near
, as well as a variation of the equilibrium distance of the graphene
sheet. A model of a wavy graphene layer is examined as a possible candidate for
understanding the nature of the minimally conducting states in graphene.Comment: 6 pages, 5 figure
Spectral problems in open quantum chaos
This review article will present some recent results and methods in the study
of 1-particle quantum or wave scattering systems, in the semiclassical/high
frequency limit, in cases where the corresponding classical/ray dynamics is
chaotic. We will focus on the distribution of quantum resonances, and the
structure of the corresponding metastable states. Our study includes the toy
model of open quantum maps, as well as the recent quantum monodromy operator
method.Comment: Compared with the previous version, misprints and typos have been
corrected, and the bibliography update
Strongly Correlated Fractional Quantum Hall Line Junctions
We have studied a clean finite-length line junction between interacting
counterpropagating single-branch fractional-quantum-Hall edge channels. Exact
solutions for low-lying excitations and transport properties are obtained when
the two edges belong to quantum Hall systems with different filling factors and
interact via the long-range Coulomb interaction. Charging effects due to the
coupling to external edge-channel leads are fully taken into account.
Conductances and power laws in the current-voltage characteristics of tunneling
are strongly affected by inter-edge correlations.Comment: 4 pages, 1 figure, RevTex4, typos corrected + references added, to
appear in Phys. Rev. Let
Symmetry Breaking in Few Layer Graphene Films
Recently, it was demonstrated that the quasiparticle dynamics, the
layer-dependent charge and potential, and the c-axis screening coefficient
could be extracted from measurements of the spectral function of few layer
graphene films grown epitaxially on SiC using angle-resolved photoemission
spectroscopy (ARPES). In this article we review these findings, and present
detailed methodology for extracting such parameters from ARPES. We also present
detailed arguments against the possibility of an energy gap at the Dirac
crossing ED.Comment: 23 pages, 13 figures, Conference Proceedings of DPG Meeting Mar 2007
Regensburg Submitted to New Journal of Physic
Open access in Southern European countries
The Spanish Foundation for Science and Technology (FECYT) is a public foundation under the Spanish Ministry of Science and Innovation whose mission is to strengthen the value chain of knowledge by fostering science and innovation and trying to integrate them and bring them closer to society, in response to the needs and expectations of the Spanish science, technology and enterprise system. The Foundationâs goal is to be recognized by Spanish society as a key reference in the dissemination, information and measurement of science and innovation. It also wishes to contribute to the development of a knowledge-based economy. One of the main challenges of the Foundation is to lead the integration and rationalization of scientific information and science, technology and innovation metrics, described as the âintegrate and measure vectorâ in its 2010- 2012 strategic plan. FECYT already has considerable experience in managing national scientific information. It is the national licensee of the Thomson Reuters Web of Knowledge accessed by the Spanish scientific community. It is also firmly committed to establishing itself as the Spanish hub in favour of the open access (OA) movement (for free access to scientific information available on the Internet), in combination with supporting the traditional markets of scientific information. In 2010 FECYT organized the 5th International Conference on Open Repositories in Madrid, with the aim of positioning Spain in the debate on emerging trends in the management of scientific information. The authorities are opening the door to the open access movement, under the belief that publicly funded research should be freely available. Among other initiatives, the 2010 Spanish Bill on Science, Technology and Innovation urges researchers to deposit their research papers produced with public funding in institutional repositories
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