19 research outputs found
A novel technique for selective NF-kappa B inhibition in Kupffer cells: contrary effects in fulminant hepatitis and ischaemia-reperfusion.
Background and aims: The transcription factor nuclear
factor kappa B (NF-kB) has risen as a promising target for
anti-inflammatory therapeutics. In the liver, however, NFkB
inhibition mediates both damaging and protective
effects. The outcome is deemed to depend on the liver
cell type addressed. Recent gene knock-out studies
focused on the role of NF-kB in hepatocytes, whereas the
role of NF-kB in Kupffer cells has not yet been
investigated in vivo. Here we present a novel approach,
which may be suitable for clinical application, to
selectively target NF-kB in Kupffer cells and analyse the
effects in experimental models of liver injury.
Methods: NF-kB inhibiting decoy oligodeoxynucleotides
were loaded upon gelatin nanoparticles (D-NPs) and their
in vivo distribution was determined by confocal microscopy.
Liver damage, NF-kB activity, cytokine levels and
apoptotic protein expression were evaluated after
lipopolysaccharide (LPS), D-galactosamine (GalN)/LPS, or
concanavalin A (ConA) challenge and partial warm
ischaemia and subsequent reperfusion, respectively.
Results: D-NPs were selectively taken up by Kupffer cells
and inhibited NF-kB activation. Inhibition of NF-kB in
Kupffer cells improved survival and reduced liver injury
after GalN/LPS as well as after ConA challenge. While
anti-apoptotic protein expression in liver tissue was not
reduced, pro-apoptotic players such as cJun N-terminal
kinase (JNK) were inhibited. In contrast, selective
inhibition of NF-kB augmented reperfusion injury.
Conclusions: NF-kB inhibiting decoy oligodeoxynucleotide-
loaded gelatin nanoparticles is a novel tool to
selectively inhibit NF-kB activation in Kupffer cells in vivo.
Thus, liver injury can be reduced in experimental fulminant
hepatitis, but increased at ischaemiaâreperfusion
What is the spatial distribution of magnetic helicity injected in a solar active region?
Copyright © 2006 EDP Sciences. This article appeared in Astronomy & Astrophysics 452 (2006) and may be found at http://www.aanda.org/index.php?option=article&access=doi&doi=10.1051/0004-6361:20054643Context. Magnetic helicity is suspected to play a key role in solar phenomena such as flares and coronal mass ejections. Several investigations have recently computed the photospheric flux of magnetic helicity in active regions. The derived spatial maps of the helicity flux density, called GA, have an intrinsic mixed-sign patchy distribution.
Aims. Pariat et al. (2005) recently showed that GA is only a proxy of the helicity flux density, which tends to create spurious polarities. They proposed a better proxy, GΞ. We investigate here the implications of this new approach on observed active regions.
Methods. The magnetic data are from MDI/SoHO instrument and the photospheric velocities are computed by local correlation tracking. Maps and temporal evolution of GA and GΞ are compared using the same data set for 5 active regions.
Results. Unlike the usual GA maps, most of our GΞ maps show almost unipolar spatial structures because the nondominant helicity flux densities are significantly suppressed. In a few cases, the GΞ maps still contain spurious bipolar signals. With further modelling we infer that the real helicity flux density is again unipolar. On time-scales larger than their transient temporal variations, the time evolution of the total helicity fluxes derived from GA and GΞ show small differences. However, unlike GA, with GΞ the time evolution of the total flux is determined primarily by the predominant-signed flux while the nondominant-signed flux is roughly stable and probably mostly due to noise.
Conclusions. Our results strongly support the conclusion that the spatial distribution of helicity injected into active regions is much more coherent than previously thought: on the active region scale the sign of the injected helicity is predominantly uniform. These results have implications for the generation of the magnetic field (dynamo) and for the physics of both flares and coronal mass ejections
In Pursuit of New Physics with B_s Decays
The presence of a sizeable CP-violating phase in B_s^0-B_s^0-bar mixing would
be an unambiguous signal of physics beyond the Standard Model. We analyse
various possibilities to detect such a new phase considering both tagged and
untagged decays. The effects of a sizeable width difference Delta Gamma between
the B_s mass eigenstates, on which the untagged analyses rely, are included in
all formulae. A novel method to find this phase from simple measurements of
lifetimes and branching ratios in untagged decays is proposed. This method does
not involve two-exponential fits, which require much larger statistics. For the
tagged decays, an outstanding role is played by the observables of the
time-dependent angular distribution of the B_s -> J/psi [-> l^+ l^-] \phi [->
K^+K^-] decay products. We list the formulae needed for the angular analysis in
the presence of both a new CP-violating phase and a sizeable Delta Gamma, and
propose methods to remove a remaining discrete ambiguity in the new phase. This
phase can therefore be determined in an unambiguous way.Comment: minor changes, lattice prediction of Delta Gamma updated, appears in
PR
Modeling magnetospheric fields in the Jupiter system
The various processes which generate magnetic fields within the Jupiter
system are exemplary for a large class of similar processes occurring at other
planets in the solar system, but also around extrasolar planets. Jupiter's
large internal dynamo magnetic field generates a gigantic magnetosphere, which
is strongly rotational driven and possesses large plasma sources located deeply
within the magnetosphere. The combination of the latter two effects is the
primary reason for Jupiter's main auroral ovals. Jupiter's moon Ganymede is the
only known moon with an intrinsic dynamo magnetic field, which generates a
mini-magnetosphere located within Jupiter's larger magnetosphere including two
auroral ovals. Ganymede's magnetosphere is qualitatively different compared to
the one from Jupiter. It possesses no bow shock but develops Alfv\'en wings
similar to most of the extrasolar planets which orbit their host stars within
0.1 AU. New numerical models of Jupiter's and Ganymede's magnetospheres
presented here provide quantitative insight into the processes that maintain
these magnetospheres. Jupiter's magnetospheric field is approximately
time-periodic at the locations of Jupiter's moons and induces secondary
magnetic fields in electrically conductive layers such as subsurface oceans. In
the case of Ganymede, these secondary magnetic fields influence the oscillation
of the location of its auroral ovals. Based on dedicated Hubble Space Telescope
observations, an analysis of the amplitudes of the auroral oscillations
provides evidence that Ganymede harbors a subsurface ocean. Callisto in
contrast does not possess a mini-magnetosphere, but still shows a perturbed
magnetic field environment. Callisto's ionosphere and atmospheric UV emission
is different compared to the other Galilean satellites as it is primarily been
generated by solar photons compared to magnetospheric electrons.Comment: Chapter for Book: Planetary Magnetis
Model-independent constraints on Delta F=2 operators and the scale of New Physics
We update the constraints on new-physics contributions to Delta F=2 processes
from the generalized unitarity triangle analysis, including the most recent
experimental developments. Based on these constraints, we derive upper bounds
on the coefficients of the most general Delta F=2 effective Hamiltonian. These
upper bounds can be translated into lower bounds on the scale of new physics
that contributes to these low-energy effective interactions. We point out that,
due to the enhancement in the renormalization group evolution and in the matrix
elements, the coefficients of non-standard operators are much more constrained
than the coefficient of the operator present in the Standard Model. Therefore,
the scale of new physics in models that generate new Delta F=2 operators, such
as next-to-minimal flavour violation, has to be much higher than the scale of
minimal flavour violation, and it most probably lies beyond the reach of direct
searches at the LHC.Comment: 32 pages, 11 figures, 6 tables. v2: error in the implementation of D0
untagged Bs->J/Psi phi correlation matrix corrected. Improved presentation of
the results and discussion of ambiguities in untagged Bs->J/Psi phi. Results
for NP in Bs oscillations changed. Final version to appear in JHE
Averages of b-hadron, c-hadron, and tau-lepton properties as of 2018 Heavy Flavor Averaging Group (HFLAV)
This paper reports world averages of measurements of b-hadron, c-hadron, and
Ï
-lepton properties obtained by the Heavy Flavour Averaging Group using results available through September 2018. In rare cases, significant results obtained several months later are also used. For the averaging, common input parameters used in the various analyses are adjusted (rescaled) to common values, and known correlations are taken into account. The averages include branching fractions, lifetimes, neutral meson mixing parameters,
C
P
violation parameters, parameters of semileptonic decays, and CabibboâKobayashiâMaskawa matrix elements
Measurement of the effective B0sâK+Kâ lifetime
A measurement of the effective lifetime is presented using approximately 37 pbâ1 of data collected by LHCb during 2010. This quantity can be used to put constraints on contributions from processes beyond the Standard Model in the meson system and is determined by two complementary approaches as
ÏKK=1.440±0.096 (stat)±0.008 (syst)±0.003 (model) ps