It is uncertain whether neurogenesis occurs in humans after stroke. We studied the morphologic changes that occurred in the subventricular zone (SVZ) in patients who died following an acute ischemic ...stroke.
We examined coronal brain slices from patients who died after a first-ever cerebral nonlacunar infarction in the middle cerebral artery territory. We evaluated the morphologic changes in the ipsilateral and contralateral SVZ by light and electron microscopy. Using immunochemistry with Ki-67 and PCNA, we detected cell proliferation. We used Tuj-1 for immature neurons and PSA-NCAM for migrating cells.
The study included 7 patients with a mean age of 82 +/- 5 (mean +/- SD) years; 4 were men. They died a mean of 10 +/- 5 days after the ischemic stroke. Brain samples were obtained a mean of 4 +/- 2 hours after death. In comparison with the contralateral SVZ, the following changes were observed in the ipsilateral SVZ: an increase in the width of the gap and ribbon layers, as well as in the cell density of the ribbon layer, an enlargement of the cytoplasmic volume of astrocytes, and an increase of Ki-67-positive cells. In the ipsilateral SVZ, mitoses and cells that stained for either Tuj-1 or PSA-NCAM markers were observed more frequently than in the contralateral SVZ.
We found unequivocal evidence of active cell proliferation in the ipsilateral subventricular zone following an acute ischemic stroke in our patients.
Here we present deep (16 Jy beam−1), very high (40 mas) angular resolution 1.14 mm, polarimetric, Atacama Large Millimeter/submillimeter Array (ALMA) observations toward the massive protostar driving ...the HH 80-81 radio jet. The observations clearly resolve the disk oriented perpendicularly to the radio jet, with a radius of 0 171 (∼291 au at 1.7 kpc distance). The continuum brightness temperature, the intensity profile, and the polarization properties clearly indicate that the disk is optically thick for a radius of R 170 au. The linear polarization of the dust emission is detected almost all along the disk, and its properties suggest that dust polarization is produced mainly by self-scattering. However, the polarization pattern presents a clear differentiation between the inner (optically thick) part of the disk and the outer (optically thin) region of the disk, with a sharp transition that occurs at a radius of ∼0 1 (∼170 au). The polarization characteristics of the inner disk suggest that dust settling has not occurred yet with a maximum dust grain size between 50 and 500 m. The outer part of the disk has a clear azimuthal pattern but with a significantly higher polarization fraction compared to the inner disk. This pattern is broadly consistent with the self-scattering of a radiation field that is beamed radially outward, as expected in the optically thin outer region, although contribution from non-spherical grains aligned with respect to the radiative flux cannot be excluded.
We present Space-VLBI RadioAstron observations at 1.6 GHz and 4.8 GHz of the flat spectrum radio quasar 3C 273, with detections on baselines up to 4.5 and 3.3 Earth Diameters, respectively. Achieving ...the best angular resolution at 1.6 GHz to date, we have imaged limb-brightening in the jet, not previously detected in this source. In contrast, at 4.8 GHz, we detected emission from a central stream of plasma, with a spatial distribution complementary to the limb-brightened emission, indicating an origin in the spine of the jet. While a stratification across the jet width in the flow density, internal energy, magnetic field, or bulk flow velocity are usually invoked to explain the limb-brightening, the different jet structure detected at the two frequencies probably requires a stratification in the emitting electron energy distribution. Future dedicated numerical simulations will allow the determination of which combination of physical parameters are needed to reproduce the spine-sheath structure observed by Space-VLBI with RadioAstron in 3C 273.
Jets in low-luminosity radio galaxies are known to decelerate from relativistic speeds on parsec scales to mildly or subrelativistic speeds on kiloparsec scales. Several mechanisms have been proposed ...to explain this effect, including strong reconfinement shocks and the growth of instabilities (both leading to boundary-layer entrainment) and mass loading from stellar winds or molecular clouds. We have performed a series of axisymmetric simulations of the early evolution of jets in a realistic ambient medium to probe the effects of mass loading from stellar winds using the code ratpenat. We study the evolution of Fanaroff–Riley Class I (FR I) jets, with kinetic powers L
j ∼ 1041–1044 erg s−1, within the first 2 kpc of their evolution, where deceleration by stellar mass loading should be most effective. Mass entrainment rates consistent with present models of stellar mass loss in elliptical galaxies produce deceleration and effective decollimation of weak FR I jets within the first kiloparsec. However, powerful FR I jets are not decelerated significantly. In those cases where the mass loading is important, the jets show larger opening angles and decollimate at smaller distances, but the overall structure and dynamics of the bow shock are similar to those of unloaded jets with the same power and thrust. According to our results, the flaring observed on kiloparsec scales is initiated by mass loading in the weaker FR I jets and by reconfinement shocks or the growth of instabilities in the more powerful jets. The final mechanism of decollimation and deceleration is always the development of disruptive pinching modes.
There is an urgent need for highly efficacious antiviral therapies in immunosuppressed hosts who develop coronavirus disease (COVID-19), with special concern for those affected by hematological ...malignancies.
Here, we report the case of a 75-year-old male with chronic lymphocytic leukemia who was deficient in CD19
CD20
B-lymphocyte populations due to previous treatment with anti-CD20 monoclonal antibodies. The patient presented with severe COVID-19 pneumonia due to prolonged severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and was treated with two courses of the antiviral plitidepsin on a compassionate use basis. The patient subsequently achieved an undetectable viral load, and his pneumonia resolved.
Treatment with plitidepsin was well-tolerated without any further hematological or cardiovascular toxicities. This case further supports plitidepsin as a potential antiviral drug in SARS-CoV-2 patients affected by immune deficiencies and hematological malignancies.
ABSTRACT This work presents the first characterization of the internal structure of overpressured, steady superfast-magnetosonic relativistic jets in connection with their dominant type of energy. To ...this aim, relativistic magnetohydrodynamic simulations of different jet models threaded by a helical magnetic field have been analyzed covering a wide region in the magnetosonic Mach number-specific internal energy plane. The merit of this plane is that models dominated by different types of energy (internal energy: hot jets; rest-mass energy: kinetically dominated jets; magnetic energy: Poynting-flux-dominated jets) occupy well-separated regions. The analyzed models also cover a wide range of magnetizations. Models dominated by the internal energy (i.e., hot models, or Poynting-flux-dominated jets with magnetizations larger than but close to one) have a rich internal structure characterized by a series of recollimation shocks and present the largest variations in the flow Lorentz factor (and internal energy density). Conversely, in kinetically dominated models, there is not much internal or magnetic energy to be converted into kinetic, and the jets are featureless with small variations in the flow Lorentz factor. The presence of a significant toroidal magnetic field threading the jet produces large gradients in the transversal profile of the internal energy density. Poynting-flux-dominated models with high magnetization ( 10 or larger) are prone to be unstable against magnetic pinch modes, which sets limits on the expected magnetization in parsec-scale active galactic nucleus jets or constrains their magnetic field configuration.
The CORNISH project is the highest resolution radio continuum survey of the Galactic plane to date. It is the 5 GHz radio continuum part of a series of multi-wavelength surveys that focus on the ...northern GLIMPSE region (10degrees < l < 65degrees), observed by the Spitzer satellite in the mid-infrared. Observations with the Very Large Array in B and BnA configurations have yielded a 1".5 resolution Stokes I map with a root mean square noise level better than 0.4 mJy beam super(-1). Here we describe the data-processing methods and data characteristics, and present a new, uniform catalog of compact radio emission. This includes an implementation of automatic deconvolution that provides much more reliable imaging than standard CLEANing. A rigorous investigation of the noise characteristics and reliability of source detection has been carried out. We show that the survey is optimized to detect emission on size scales up to 14" and for unresolved sources the catalog is more than 90% complete at a flux density of 3.9 mJy. We have detected 3062 sources above a 7sigma detection limit and present their ensemble properties. The catalog is highly reliable away from regions containing poorly sampled extended emission, which comprise less than 2% of the survey area. Imaging problems have been mitigated by down-weighting the shortest spacings and potential artifacts flagged via a rigorous manual inspection with reference to the Spitzer infrared data. We present images of the most common source types found: H II regions, planetary nebulae, and radio galaxies. The CORNISH data and catalog are available online at http://cornish.leeds.ac.uk.
ObjectiveThe aim of this review was to evaluate the conceptual suitability, applicability and psychometric properties of scores used internationally to measure adherence to the Mediterranean diet ...(MD).DesignThis was a systematic review to identify original articles that examined some aspects of the conceptual suitability, applicability or psychometric properties of the MD adherence score. Electronic searches were carried out on the international databases MEDLINE, Scopus, Web of Science and EMBASE (from January 1980 to 31 December 2015).Eligibility criteria for selecting studiesThe study included original articles that examined some aspects of the conceptual suitability, applicability or psychometric properties of the MD adherence score. The studies where MD adherence scores were administered but did not bring forward any evidence about their performance related to conceptual suitability, applicability or psychometric properties were excluded.Data extractionInformation relating to the scales was extracted in accordance with the quality criteria defined by the Scientific Advisory Committee of the Medical Outcomes Trust for measurement of health results and the quality criteria recommended by Terwee: (1) conceptual, (2) applicability and (3) psychometric properties. Three authors independently extracted information from eligible studies.ResultsTwenty-seven studies were identified as meeting the inclusion criteria, yielding 28 MD adherence scores. The results showed that evidence is scarce and that very few scores fulfilled the applicability parameters and psychometric quality. The scores developed by Panagiotakos et al, Buckland et al and Sotos-Prieto et al showed the highest levels of evidence.ConclusionsScores measuring adherence to MD are useful tools for identifying the dietary patterns of a given population. However, further information is required regarding existing scores. In addition, new instruments with greater conceptual and methodological rigour should be developed and evaluated for their psychometric properties.
Background and purpose
Plaque neovascularization is a hallmark of carotid plaque vulnerability. With contrast‐enhanced ultrasound (CEUS) it is possible to visualize plaque neovessels in vivo. Our aim ...was to determine if CEUS‐detected neovessels were associated with stroke recurrences in patients with a recent stroke and carotid atherosclerosis.
Methods
We conducted a prospective study of consecutive patients with a recent stroke and at least one atherosclerotic plaque in the internal carotid artery on the side consistent with symptoms. All of our patients underwent a carotid ultrasound examination including a CEUS study. Neovascularization was graded into three categories according to the extent of neovessels. During the follow‐up, we recorded stroke recurrences. A multivariable Cox regression analysis was performed to evaluate predictors of recurrence.
Results
We included 78 patients whose mean age was 74.3 ± 10.4 years. There were 29 (37.2%) patients with a low‐grade stenosis (<50%). The remainder presented moderate (50%–69%) or high‐grade (≥70%) stenosis. CEUS was not interpretable in 35.9% of the patients, mainly due to calcium shadows. We detected neovascularization in 80% of the plaques. After a median follow‐up of 14.1 (interquartile range, 9.5‐19.6) months, there were 15 (19.2%) stroke recurrences. In the Cox regression analysis, CEUS‐detected neovascularization was independently associated with the risk of stroke recurrence, even after adjusting for the degree of stenosis (hazard ratio, 6.57; 95% confidence interval, 1.66–26.01).
Conclusion
In patients with an anterior circulation ischaemic stroke and carotid atherosclerosis, plaque neovascularization detected with CEUS was an independent predictor of stroke recurrence.
The evolution of Fanaroff–Riley type I (FR I) jets has long been studied in the framework of the FR I–FR II dichotomy. The present paradigm consists of the expansion of overpressured jets in the ...ambient medium and the generation of standing recollimation shocks, followed by mass entrainment from the external medium that decelerates the jets to subsonic speeds. In this paper, we test the present theoretical and observational models via a relativistic numerical simulation of the jets in the radio galaxy 3C 31. We use the parameters derived from the modelling presented by Laing & Bridle as input parameters for the simulation of the evolution of the source, thus assuming that they have not varied over the lifetime of the source. We simulate about 10 per cent of the total lifetime of the jets in 3C 31. Realistic density and pressure gradients for the atmosphere are used. The simulation includes an equation of state for a two-component relativistic gas that allows a separate treatment of leptonic and baryonic matter. We compare our results with the modelling of the observational data of the source. Our results show that the bow shock evolves self-similarly at a quasi-constant speed, with slight deceleration by the end of the simulation, in agreement with recent X-ray observations that show the presence of bow shocks in FR I sources. The jet expands until it becomes underpressured with respect to the ambient medium, and then recollimates. Subsequent oscillations around pressure equilibrium and generation of standing shocks lead to the mass-loading and disruption of the jet flow. We derive an estimate for the minimum age of the source of t > 1 × 108 yr, which may imply continuous activity of 3C 31 since the triggering of its activity. The simulation shows that weak compact steep spectrum sources may be the young counterparts of FR I sources. We conclude that the observed properties of the jets in 3C 31 are basically recovered by the standing shock scenario.
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