260 research outputs found
Electrical stimulation of the mesencephalic locomotor region attenuates neuronal loss and cytokine expression in the perifocal region of photothrombotic stroke in rats
Deep brain stimulation of the mesencephalic locomotor region (MLR) improves the motor symptoms in Parkinson’s disease and experimental stroke by intervening in the motor cerebral network. Whether high-frequency stimulation (HFS) of the MLR is involved in non-motor processes, such as neuroprotection and inflammation in the area surrounding the photothrombotic lesion, has not been elucidated. This study evaluates whether MLR-HFS exerts an anti-apoptotic and anti-inflammatory effect on the border zone of cerebral photothrombotic stroke. Rats underwent photothrombotic stroke of the right sensorimotor cortex and the implantation of a microelectrode into the ipsilesional MLR. After intervention, either HFS or sham stimulation of the MLR was applied for 24 h. The infarct volumes were calculated from consecutive brain sections. Neuronal apoptosis was analyzed by TUNEL staining. Flow cytometry and immunohistochemistry determined the perilesional inflammatory response. Neuronal apoptosis was significantly reduced in the ischemic penumbra after MLR-HFS, whereas the infarct volumes did not differ between the groups. MLR-HFS significantly reduced the release of cytokines and chemokines within the ischemic penumbra. MLR-HFS is neuroprotective and it reduces pro-inflammatory mediators in the area that surrounds the photothrombotic stroke without changing the number of immune cells, which indicates that MLR-HFS enables the function of inflammatory cells to be altered on a molecular level
Considering Polymorphism in Change-Based Test Suite Reduction
With the increasing popularity of continuous integration, algorithms for
selecting the minimal test-suite to cover a given set of changes are in order.
This paper reports on how polymorphism can handle false negatives in a previous
algorithm which uses method-level changes in the base-code to deduce which
tests need to be rerun. We compare the approach with and without polymorphism
on two distinct cases ---PMD and CruiseControl--- and discovered an interesting
trade-off: incorporating polymorphism results in more relevant tests to be
included in the test suite (hence improves accuracy), however comes at the cost
of a larger test suite (hence increases the time to run the minimal
test-suite).Comment: The final publication is available at link.springer.co
Origin of spatial variations of scattering polarization in the wings of the Ca {\sc i} 4227 \AA line
Polarization that is produced by coherent scattering can be modified by
magnetic fields via the Hanle effect. According to standard theory the Hanle
effect should only be operating in the Doppler core of spectral lines but not
in the wings. In contrast, our observations of the scattering polarization in
the Ca {\sc i} 4227 \AA line reveals the existence of spatial variations of the
scattering polarization throughout the far line wings. This raises the question
whether the observed spatial variations in wing polarization have a magnetic or
non-magnetic origin. A magnetic origin may be possible if elastic collisions
are able to cause sufficient frequency redistribution to make the Hanle effect
effective in the wings without causing excessive collisional depolarization, as
suggested by recent theories for partial frequency redistribution with coherent
scattering in magnetic fields. To model the wing polarization we apply an
extended version of the technique based on the "last scattering approximation".
This model is highly successful in reproducing the observed Stokes
polarization (linear polarization parallel to the nearest solar limb),
including the location of the wing polarization maxima and the minima around
the Doppler core, but it fails to reproduce the observed spatial variations of
the wing polarization in terms of magnetic field effects with frequency
redistribution. This null result points in the direction of a non-magnetic
origin in terms of local inhomogeneities (varying collisional depolarization,
radiation-field anisotropies, and deviations from a plane-parallel atmospheric
stratification).Comment: Accepted in May 2009 for publication in The Astrophysical Journa
Measurement of the proton and deuteron structure functions, F2p and F2d, and of the ratio sigma(L)/sigma(T)
The muon-proton and muon-deuteron inclusive deep inelastic scattering cross
sections were measured in the kinematic range 0.002 < x < 0.60 and 0.5 < Q2 <
75 GeV2 at incident muon energies of 90, 120, 200 and 280 GeV. These results
are based on the full data set collected by the New Muon Collaboration,
including the data taken with a small angle trigger. The extracted values of
the structure functions F2p and F2d are in good agreement with those from other
experiments. The data cover a sufficient range of y to allow the determination
of the ratio of the longitudinally to transversely polarised virtual photon
absorption cross sections, R= sigma(L)/sigma(T), for 0.002 < x < 0.12 . The
values of R are compatible with a perturbative QCD prediction; they agree with
earlier measurements and extend to smaller x.Comment: In this replacement the erroneously quoted R values in tables 3-6 for
x>0.12, and R1990 values in tables 5-6 for all x, have been corrected, and
the cross sections in tables 3-4 have been adapted. Everything else,
including the structure functions F2, remained unchanged. 22 pages, LateX,
including figures, with two .sty files, and three separate f2tab.tex files
for the F2-tables. Accepted for publication in Nucl.Phys.B 199
Debye-Hueckel solution for steady electro-osmotic flow of a micropolar fluid in a cylindrical microcapillary
Analytic expressions for the speed, flux, microrotation, stress, and couple
stress in a micropolar fluid exhibiting steady, symmetric and one-dimensional
electro-osmotic flow in a uniform cylindrical microcapillary were derived under
the constraint of the Debye-Hueckel approximation, which is applicable when the
cross-sectional radius of the microcapillary exceeds the Debye length, provided
that the zeta potential is sufficiently small in magnitude. As the aciculate
particles in a micropolar fluid can rotate without translation, micropolarity
influences fluid speed, fluid flux, and one of the two non-zero components of
the stress tensor. The axial speed in a micropolar fluid intensifies as the
radius increases. The stress tensor is confined to the region near the wall of
the microcapillary but the couple stress tensor is uniform across the
cross-section.Comment: 19 page
The IMPROVE guidelines (Ischaemia Models: Procedural Refinements Of in Vivo Experiments)
Most in vivo models of ischaemic stroke target the middle cerebral artery and a spectrum of stroke severities, from mild to substantial, can be achieved. This review describes opportunities to improve the in vivo modelling of ischaemic stroke and animal welfare. It provides a number of recommendations to minimise the level of severity in the most common rodent models of middle cerebral artery occlusion, while sustaining or improving the scientific outcomes. The recommendations cover basic requirements pre-surgery, selecting the most appropriate anaesthetic and analgesic regimen, as well as intraoperative and post-operative care. The aim is to provide support for researchers and animal care staff to refine their procedures and practices, and implement small incremental changes to improve the welfare of the animals used and to answer the scientific question under investigation. All recommendations are recapitulated in a summary poster (see supplementary information)
Measurement of the proton and the deuteron structure functions F2p and F2d
The proton and deuteron structure functions F2p and F2d were measured in the
kinematic range 0.006<x<0.6 and 0.5<Q^2<75 GeV^2, by inclusive deep inelastic
muon scattering at 90, 120, 200 and 280 GeV. The measurements are in good
agreement with earlier high precision results. The present and earlier results
together have been parametrised to give descriptions of the proton and deuteron
structure functions F2 and their uncertainties over the range 0.006<x<0.9.Comment: 22 pages, using LATEX, 12pt, epsfig.sty, rotating.sty; 2 tables and 6
figures uuencoded compressed tar files in f2fig.uu (Corrected two values of
Table 3 into c3=-35.01 and c4=44.43 for "Upper F2p".
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