304 research outputs found
Dual Microsporidial Infection Due to Vittaforma corneae and Encephalitozoon hellem in a Patient with AIDS
A 46-year-old human immunodeficiency virus-infected Swiss citizen living in Tanzania presented with respiratory, abdominal, and urogenital complaints. Microsporidial spores were isolated from urine and a sinunasal aspirate and were propagated in MRC-5 cell cultures. Western blot analysis and riboprinting identified the sinunasal isolate as Encephalitozoon hellem. Electron microscopic investigation of the urine isolate revealed spores with diplokaryotic nuclei and five to six isofilar coils of the polar tube and sporonts with two or three diplokarya. All stages were enveloped by two membranes, corresponding to a cisterna of host endoplasmic reticulum studded with ribosomes. These characteristics have been described for the genus Vittaforma. Western blot analysis of this isolate revealed a banding pattern identical to that of the Vittaforma corneae reference isolate. Part of the small subunit rRNA gene was amplified, sequenced (239 base pairs), and found to be identical to that of V. corneae. This is the second isolation of V. corneae and the first description of urinary tract infection due to V. corneae in a patient with AID
Constraints on thermal conductivity in the merging cluster Abell 2146
The cluster of galaxies Abell 2146 is undergoing a major merger and is an
ideal cluster to study ICM physics, as it has a simple geometry with the merger
axis in the plane of the sky, its distance allows us to resolve features across
the relevant scales and its temperature lies within Chandra's sensitivity. Gas
from the cool core of the subcluster has been partially stripped into a tail of
gas, which gives a unique opportunity to look at the survival of such gas and
determine the rate of conduction in the ICM. We use deep 2.4 Ms Chandra
observations of Abell 2146 to produce a high spatial resolution map of the
temperature structure along a plume in the ram-pressure stripped tail,
described by a partial cone, which is distinguishable from the hot ambient gas.
Previous studies of conduction in the ICM typically rely on estimates of the
survival time for key structures, such as cold fronts. Here we use detailed
hydrodynamical simulations of Abell 2146 to determine the flow velocities along
the stripped plume and measure the timescale of the temperature increase along
its length. We find that conduction must be highly suppressed by multiple
orders of magnitude compared to the Spitzer rate, as the energy used is about
1% of the energy available. We discuss magnetic draping around the core as a
possible mechanism for suppressing conduction.Comment: 10 pages, 3 figures, 3 tables, accepted for publication in MNRA
Constraints on thermal conductivity in the merging cluster Abell 2146
The cluster of galaxies Abell 2146 is undergoing a major merger and is an ideal cluster to study ICM physics, as it has a simple geometry with the merger axis in the plane of the sky, its distance allows us to resolve features across the relevant scales and its temperature lies within Chandra's sensitivity. Gas from the cool core of the subcluster has been partially stripped into a tail of gas, which gives a unique opportunity to look at the survival of such gas and determine the rate of conduction in the ICM. We use deep 2.4 Ms Chandra observations of Abell 2146 to produce a high spatial resolution map of the temperature structure along a plume in the ram-pressure stripped tail, described by a partial cone, which is distinguishable from the hot ambient gas. Previous studies of conduction in the ICM typically rely on estimates of the survival time for key structures, such as cold fronts. Here we use detailed hydrodynamical simulations of Abell 2146 to determine the flow velocities along the stripped plume and measure the timescale of the temperature increase along its length. We find that conduction must be highly suppressed by multiple orders of magnitude compared to the Spitzer rate, as the energy used is about 1% of the energy available. We discuss magnetic draping around the core as a possible mechanism for suppressing conduction
The structure of cluster merger shocks: turbulent width and the electron heating time-scale
We present a new 2 Ms Chandra observation of the cluster merger Abell 2146, which hosts two huge MâŒ2 shock fronts each âŒ500 kpc across. For the first time, we resolve and measure the width of cluster merger shocks. The best-fit width for the bow shock is 17 ± 1 kpc and for the upstream shock is 10.7 ± 0.3 kpc. A narrow collisionless shock will appear broader in projection if its smooth shape is warped by local gas motions. We show that both shock widths are consistent with collisionless shocks blurred by local gas motions of 290 ± 30 km s â1. The upstream shock forms later on in the merger than the bow shock and is therefore expected to be significantly narrower. From the electron temperature profile behind the bow shock, we measure the timescale for the electrons and ions to come back into thermal equilibrium. We rule out rapid thermal equilibration of the electrons with the shock-heated ions at the 6Ï level. The observed temperature profile instead favours collisional equilibration. We find no evidence for electron heating over that produced by adiabatic compression. This supports the existing picture from collisionless shocks in the solar wind and supernova remnants. The upstream shock is consistent with this result but has a more complex structure, including a ⌠2 keV increase in temperature âŒ50 kpc ahead of the shock
Quantum Cryptography
Quantum cryptography could well be the first application of quantum mechanics
at the individual quanta level. The very fast progress in both theory and
experiments over the recent years are reviewed, with emphasis on open questions
and technological issues.Comment: 55 pages, 32 figures; to appear in Reviews of Modern Physic
The epithelial cholinergic system of the airways
Acetylcholine (ACh), a classical transmitter of parasympathetic nerve fibres in the airways, is also synthesized by a large number of non-neuronal cells, including airway surface epithelial cells. Strongest expression of cholinergic traits is observed in neuroendocrine and brush cells but other epithelial cell typesâciliated, basal and secretoryâare cholinergic as well. There is cell type-specific expression of the molecular pathways of ACh release, including both the vesicular storage and exocytotic release known from neurons, and transmembrane release from the cytosol via organic cation transporters. The subcellular distribution of the ACh release machineries suggests luminal release from ciliated and secretory cells, and basolateral release from neuroendocrine cells. The scenario as known so far strongly suggests a local auto-/paracrine role of epithelial ACh in regulating various aspects on the innate mucosal defence mechanisms, including mucociliary clearance, regulation of macrophage function and modulation of sensory nerve fibre activity. The proliferative effects of ACh gain importance in recently identified ACh receptor disorders conferring susceptibility to lung cancer. The cell type-specific molecular diversity of the epithelial ACh synthesis and release machinery implies that it is differently regulated than neuronal ACh release and can be specifically targeted by appropriate drugs
Minimum toe clearance events in divided attention treadmill walking in older and young adults: a cross-sectional study
Trends in Outcomes for Neonates Born Very Preterm and Very Low Birth Weight in 11 High-Income Countries
Objective
To evaluate outcome trends of neonates born very preterm in 11 high-income countries participating in the International Network for Evaluating Outcomes of neonates. Study design In a retrospective cohort study, we included 154 233 neonates admitted to 529 neonatal units between January 1, 2007, and December 31, 2015, at 24(0/7) to 31(6/7) weeks of gestational age and birth weight <1500 g. Composite outcomes were in-hospital mortality or any of severe neurologic injury, treated retinopathy of prematurity, and bronchopulmonary dysplasia (BPD); and same composite outcome excluding BPD. Secondary outcomes were mortality and individual morbidities. For each country, annual outcome trends and adjusted relative risks comparing epoch 2 (2012-2015) to epoch 1 (2007-2011) were analyzed.
Results
For composite outcome including BPD, the trend decreased in Canada and Israel but increased in Australia and New Zealand, Japan, Spain, Sweden, and the United Kingdom. For composite outcome excluding BPD, the trend decreased in all countries except Spain, Sweden, Tuscany, and the United Kingdom. The risk of composite outcome was lower in epoch 2 than epoch 1 in Canada (adjusted relative risks 0.78; 95% CI 0.74-0.82) only. The risk of composite outcome excluding BPD was significantly lower in epoch 2 compared with epoch 1 in Australia and New Zealand, Canada, Finland, Japan, and Switzerland. Mortality rates reduced in most countries in epoch 2. BPD rates increased significantly in all countries except Canada, Israel, Finland, and Tuscany.
Conclusions
In most countries, mortality decreased whereas BPD increased for neonates born very preterm
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