697 research outputs found
HIV-Infektion : Update 2009 fĂŒr HausĂ€rzte. Teil 1
Quintessenz: In der Schweiz werden jÀhrlich >750 HIV-Infektionen neu diagnostiziert. Die Ansteckung geschieht via Blut oder Sex, und nicht bei alltÀglichen
sozialen Kontakten. Die CD4-Lymphozytenzahl ist bestens etabliert zur Messung der Immunsuppression. Die grösste Gefahr opportunistischer Infekte droht bei CD4-Werten <200/ÎŒl. Dank antiretroviraler Therapie (ART) sollten viele HIV-infizierte Patienten in der Schweiz eine quasi normale Lebenserwartung haben. Momentan ist eine ART bei CD4-Werten <350/ÎŒl indiziert. Die HIV-Diagnose wird auch in der Schweiz hĂ€ufig zu spĂ€t gestellt. HausĂ€rzte spielen bei der frĂŒhzeitigen Diagnosestellung (grosszĂŒgiges Anbieten von HIV-Tests) und bei der PrĂ€vention von Immundefizienz und
opportunistischen Komplikationen eine entscheidende Rolle.
P Bei HIV-Neudiagnose soll der Patient einem HIV-Spezialisten zugewiesen werden, um weitere AbklĂ€rungen durchzufĂŒhren und die Indikation zum ART-Beginn zu stellen
Reconstructing fossil sub-structures of the Galactic disk: clues from abundance patterns of old open clusters and moving groups
The long term goal of large-scale chemical tagging is to use stellar
elemental abundances as a tracer of dispersed substructures of the Galactic
disk. The identification of such lost stellar aggregates and the exploration of
their chemical properties will be key in understanding the formation and
evolution of the disk. Present day stellar structures such as open clusters and
moving groups are the ideal testing grounds for the viability of chemical
tagging, as they are believed to be the remnants of the original larger
starforming aggregates. Until recently, high accuracy elemental abundance
studies of open clusters and moving groups having been lacking in the
literature. In this paper we examine recent high resolution abundance studies
of open clusters to explore the various abundance trends and reasses the
prospects of large-scale chemical tagging.Comment: Accepted for publication in the Publications of the Astronomical
Society of Australi
Systematic motions in the Galactic plane found in the Hipparcos Catalogue using Herschel's Method
Two motions in the galactic plane have been detected and characterized, based
on the determination of a common systematic component in Hipparcos catalogue
proper motions. The procedure is based only on positions, proper motions and
parallaxes, plus a special algorithm which is able to reveal systematic trends.
Our results come from two stellar samples. Sample 1 has 4566 stars and defines
a motion of apex (l,b)=(177.8,3.7)+/-(1.5,1.0) and space velocity V=27+/-1
km/s. Sample 2 has 4083 stars and defines a motion of apex
(l,b)=(5.4,-0.6)+/-(1.9,1.1) and space velocity V=32+/-2 km/s. Both groups are
distributed all over the sky and cover a large variety of spectral types, which
means that they do not belong to a specific stellar population. Herschel's
method is used to define the initial samples of stars and later to compute the
common space velocity. The intermediate process is based on the use of a
special algorithm to determine systematic components in the proper motions. As
an important contribution, this paper sets out a new way to study the
kinematics of the solar neighborhood, in the search for streams, associations,
clusters and any other space motion shared by a large number of stars, without
being restricted by the availability of radial velocities.Comment: 12 pages and 12 eps figures. LaTe
Haemodialysis activates phospholipase A2 enzyme
Background Clinical and experimental evidence suggest that haemodialysis (HD) procedure is an inflammatory process. For the production of proinflammatory lipid mediators in many inflammatory reactions, the release of arachidonic acid by phospholipase A2 (PLA2 enzyme is a prerequisite. Therefore, the purpose of the present investigation was to establish whether the activity of PLA2 increases during HD and whether the increase depends on the type of dialyser used. Methods We performed dialysis in eight chronic HD patients. Blood samples entering and leaving the dialyser were obtained before and at 15, 60, 120 and 180 min after the dialysis was started, on one occasion using a cuprophane and on another occasion a cellulose triacetate dialyser. PLA2 activity was assessed in crude plasma and in plasma extract. Results PLA2 activity in plasma extract exhibited similar biochemical properties to that of inflammatory human synovial fluid PLA2 enzyme which is of group II PLA2. PLA2 activity in crude plasma represents a type of PLA2 other than the synovial type. In HD patients, baseline PLA2 activities in crude plasma and plasma extract were significantly increased when compared to normal subjects. An increase in PLA2 activity was observed in crude plasma with a peak appearing at 15 min when the patients were dialysed with cuprophane and cellulose triacetate membranes. This increase was observed in both arterial and venous blood samples and was more pronounced when the patients were dialysed with cuprophane than with cellulose triacetate membranes. When PLA2 was assessed in plasma extract, the activity increased only with cuprophane but not with cellulose triacetate membranes. Conclusions PLA2 activity in plasma is increased in HD patients and increases during the dialysis procedure to a greater extent with a less biocompatible membrane. Continuous activation of PLA2 might be relevant for long-term deleterious consequences of H
Invariant manifolds and the response of spiral arms in barred galaxies
The unstable invariant manifolds of the short-period family of periodic
orbits around the unstable Lagrangian points and of a barred galaxy
define loci in the configuration space which take the form of a trailing spiral
pattern. In the present paper we investigate this association in the case of
the self-consistent models of Kaufmann & Contopoulos (1996) which provide an
approximation of real barred-spiral galaxies. We also examine the relation of
`response' models of barred-spiral galaxies with the theory of the invariant
manifolds. Our main results are the following: The invariant manifolds yield
the correct form of the imposed spiral pattern provided that their calculation
is done with the spiral potential term turned on. We provide a theoretical
model explaining the form of the invariant manifolds that supports the spiral
structure. The azimuthal displacement of the Lagrangian points with respect to
the bar's major axis is a crucial parameter in this modeling. When this is
taken into account, the manifolds necessarily develop in a spiral-like domain
of the configuration space, delimited from below by the boundary of a
banana-like non-permitted domain, and from above either by rotational KAM tori
or by cantori forming a stickiness zone. We construct `spiral response' models
on the basis of the theory of the invariant manifolds and examine the
connection of the latter to the `response' models (Patsis 2006) used to fit
real barred-spiral galaxies, explaining how are the manifolds related to a
number of morphological features seen in such models.Comment: 16 Page
Formation of Nuclear Spirals in Barred Galaxies
We have performed smoothed particle hydrodynamics (SPH) simulations for the
response of the gaseous disk to the imposed moderately strong non-axisymmetric
potentials. The model galaxies are composed of the three stellar components
(disk, bulge and bar) and two dark ones (supermassive black hole and halo)
whose gravitational potentials are assumed to be invariant in time in the frame
corotating with the bar. We found that the torques alone generated by the
moderately strong bar that gives the maximum of tangential-to-radial force
ratio as are not sufficient to drive the gas
particles close to the center due to the barrier imposed by the inner Lindblad
resonances (ILRs). In order to transport the gas particles towards the nucleus
( pc), a central supermassive black hole (SMBH) and high sound speed of
the gas are required to be present. The former is required to remove the inner
inner Lindblad resonance (IILR) that prevents gas inflow close to the nucleus,
while the latter provides favourable conditions for the gas particles to lose
their angular momentum and to spiral in. Our models that have no IILR show the
trailing nuclear spirals whose innermost parts reach close to the center in a
curling way when the gas sound speed is km s. They
resemble the symmetric two-armed nuclear spirals observed in the central
kiloparsec of spiral galaxies. We found that the symmetric two-armed nuclear
spirals are formed by the hydrodynamic spiral shocks caused by the
gravitational torque of the bar in the presence of a central SMBH that can
remove IILR when the sound speed of gas is high enough to drive a large amount
of gas inflow deep inside the ILR. However, the detailed morphology of nuclear
spirals depends on the sound speed of gas.Comment: 38 pages, 10 figures, accepted for publication in Ap
The large scale dust lanes of the Galactic bar
(abridged) By comparing the distribution of dust and gas in the central
regions of the Galaxy, we aim to obtain new insights into the properties of the
offset dust lanes leading the bar's major axis in the Milky Way. On the one
hand, the molecular emission of the dust lanes is extracted from the observed
CO l-b-V distribution according to the interpretation of a dynamical model. On
the other hand, a three dimensional extinction map of the Galactic central
region constructed from near-infrared observations is used as a tracer of the
dust itself and clearly reveals dust lanes in its face-on projection.
Comparison of the position of both independent detections of the dust lanes is
performed in the (l, b) plane. These two completely independent methods are
used to provide a coherent picture of the dust lanes in the Milky Way bar. In
both the gas and dust distributions, the dust lanes are found to be out of the
Galactic plane, appearing at negative latitudes for l > 0 deg and at positive
latitudes for l < 0 deg. However, even though there is substantial overlap
between the two components, they are offset from one another with the dust
appearing to lie closer to the b = 0 deg plane. Two scenarios are proposed to
explain the observed offset. The first involves grain destruction by the bar
shock and reformation downstream. Due to the decrease in velocity caused by the
shock, this occurs at lower z. The second assumes that the gas and dust remain
on a common tilted plane, but that the molecular gas decouples from the Milky
Way's magnetic field, itself strong enough to resist the shear of the bar's
shock. The diffuse gas and dust remain coupled to the field and are carried
further downstream. This second scenario has recently been suggested in order
to explain observations of the barred galaxy NGC 1097.Comment: 4 pages, 5 figures, accepted for publication in Astronomy and
Astrophysics letter
Efficacy and safety of secukinumab for the treatment of severe ABCA12 deficiencyârelated ichthyosis in a child
Summary Background Patients with severe autosomal recessive congenital ichthyosis (ARCI) show a T helper 17/interleukin 17 (Th17/IL17) skewing in their skin and serum, resembling the inflammatory profile of psoriatic patients. Secukinumab, an ILâ17A inhibitor, has shown clinical efficacy in patients with moderateâtoâsevere plaque psoriasis. Aims To test the clinical efficacy and safety of secukinumab in a paediatric patient with ATPâbinding cassette subfamily A member 12 deficiencyârelated severe erythrodermic ARCI. Materials & Methods 6âmonths therapeutic trial. During the first 4âweeks induction period, the patient received weekly subcutaneous injections of 150 mg secukinumab (five injections in total). During the following 20âweeks maintenance period, the patient was given a subcutaneous injection of 150 mg secukinumab every 4 weeks. Result & Discussion After the 6âmonths therapy period, there was a 48% reduction from the baseline IchthyosisâAreaâSeverityâIndex (âErythema/âScaling) score. The treatment was well tolerated. Moreover, cytokine analysis revealed a reduction of keratinocyteâderived proinflammatory cytokines and an abrogation of Th17âskewing during therapy. Conclusion Further studies are needed to evaluate the effects of the use of ILâ17A inhibition in ARCI patients
An inner ring and the micro lensing toward the Bulge
All current Bulge-Disk models for the inner Galaxy fall short of reproducing
self-consistently the observed micro-lensing optical depth by a factor of two
(). We show that the least mass-consuming way to increase the
optical depth is to add density roughly half-way the observer and the highest
micro-lensing-source density. We present evidence for the existence of such a
density structure in the Galaxy: an inner ring, a standard feature of barred
galaxies. Judging from data on similar rings in external galaxies, an inner
ring can contribute more than 50% of a pure Bulge-Disk model to the
micro-lensing optical depth. We may thus eliminate the need for a small viewing
angle of the Bar. The influence of an inner ring on the event-duration
distribution, for realistic viewing angles, would be to increase the fraction
of long-duration events toward Baade's window. The longest events are expected
toward the negative-longitude tangent point at -22\degr . A properly
sampled event-duration distribution toward this tangent point would provide
essential information about viewing angle and elongation of the over-all
density distribution in the inner Galaxy.Comment: 9 pages, 7(15) figs, LaTeX, AJ (accepted
Development and validation of a risk score for chronic kidney disease in HIV infection using prospective cohort data from the D:A:D study.
Chronic kidney disease (CKD) is a major health issue for HIV-positive individuals, associated with increased morbidity and mortality. Development and implementation of a risk score model for CKD would allow comparison of the risks and benefits of adding potentially nephrotoxic antiretrovirals to a treatment regimen and would identify those at greatest risk of CKD. The aims of this study were to develop a simple, externally validated, and widely applicable long-term risk score model for CKD in HIV-positive individuals that can guide decision making in clinical practice
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