462 research outputs found

    Post-mortem diagnosis of intravascular large B-cell lymphoma

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    Intravascular large B-cell lymphoma (IVLBCL) is a rare (<1%), typically aggressive extranodal variant of mature non-Hodgkin B-cell lymphoma. IVLBCL is characterized by malignant lymphoid cells lodged within blood vessels, particularly capillary channels. Herein, we present a case of a 50-year-old man with a history of myeloradiculitis (∼1 year) and paraparesis requiring hospitalization. During the course of his hospital stay, computed tomography (CT), magnetic resonance imaging, CT-positron emission tomography, and biopsy failed to establish a diagnosis. The patient died 2 months later from bilateral pneumonia. Postmortem examination was undertaken to determine the cause of death. Histologic sections of the patient’s brain, heart, lung, and liver showed aggregates of highly atypical cells bearing enlarged, pleomorphic, and hyperchromatic nuclei. Strong intravascular positivity for CD45 and CD20 markers indicated the cells were of B-cell origin, supporting a diagnosis of IVLBCL

    Comparing extrapolations of the coronal magnetic field structure at 2.5 solar radii with multi-viewpoint coronagraphic observations

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    The magnetic field shapes the structure of the solar corona but we still know little about the interrelationships between the coronal magnetic field configurations and the resulting quasi-stationary structures observed in coronagraphic images (as streamers, plumes, coronal holes). One way to obtain information on the large-scale structure of the coronal magnetic field is to extrapolate it from photospheric data and compare the results with coronagraphic images. Our aim is to verify if this comparison can be a fast method to check systematically the reliability of the many methods available to reconstruct the coronal magnetic field. Coronal fields are usually extrapolated from photospheric measurements typically in a region close to the central meridian on the solar disk and then compared with coronagraphic images at the limbs, acquired at least 7 days before or after to account for solar rotation, implicitly assuming that no significant changes occurred in the corona during that period. In this work, we combine images from three coronagraphs (SOHO/LASCO-C2 and the two STEREO/SECCHI-COR1) observing the Sun from different viewing angles to build Carrington maps covering the entire corona to reduce the effect of temporal evolution to ~ 5 days. We then compare the position of the observed streamers in these Carrington maps with that of the neutral lines obtained from four different magnetic field extrapolations, to evaluate the performances of the latter in the solar corona. Our results show that the location of coronal streamers can provide important indications to discriminate between different magnetic field extrapolations.Comment: Accepted by A&A the 20th of May, 201

    Autopsy findings in COVID-19-related deaths. A literature review

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    Although many clinical reports have been published, little is known about the pathological post-mortem findings from people who have died of the novel coronavirus disease. The need for postmortem information is urgent to improve patient management of mild and severe illness, and treatment strategies. The present systematic review was carried out according to the Preferred Reporting Items for Systematic Review (PRISMA) standards. A systematic literature search and a critical review of the collected studies were conducted. An electronic search of PubMed, Science Direct Scopus, Google Scholar, and Excerpta Medica Database (EMBASE) from database inception to June 2020 was performed. We found 28 scientific papers; the total amount of cases is 341. The major histological feature in the lung is diffuse alveolar damage with hyaline membrane formation, alongside microthrombi in small pulmonary vessels. It appears that there is a high incidence of deep vein thrombosis and pulmonary embolism among COVID-19 decedents, suggesting endothelial involvement, but more studies are needed. A uniform COVID-19 post-mortem diagnostic protocol has not yet been developed. In a time in which international collaboration is essential, standardized diagnostic criteria are fundamental requirements

    B-type natriuretic peptide levels predict extent and severity of coronary disease in non-ST elevation coronary syndromes and normal left ventricular systolic function.

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    BACKGROUND: B-type natriuretic peptide (BNP) has been used recently as a biological marker in patients with coronary artery disease (CAD) with ST-elevation, as well as without ST-elevation. BNP is able to predict systolic dysfunction, adding new prognostic information to existing traditional markers. However is not known if there is a relation between the quantity of BNP levels and the severity of coronary artery disease. METHODS: This study compared B-type natriuretic peptide (BNP) levels in patients with stable angina (SA) and acute coronary syndromes (ACS) without ST-elevation in relation to angiographic lesions using TIMI and Gensini Scores. We studied 282 patients with CAD without ST elevation and preserved systolic function. BNP samples were measured in all recruited patients within 24 hours of hospitalization. RESULTS: BNP values were progressively increased in relation to the severity of diagnosis: SA (52.6±49.4 pg/mL ) UA (243.3±212 pg/mL) NSTE-ACS (421.7±334 pg/mL) (p<0.0001 and p<0.007 respectively). No statistically significant difference was observed between patients with SA and controls (21.2±6.8 pg/mL). The analysis of BNP levels in relation to the number of involved vessels demonstrated significantly increased levels in patients with multivessel disease compared to patients with 1 or 2 vessel disease (1-86.2±46.3 pg/mL; 2-127±297 pg/mL; 3-295±318 pg/mL; 4-297±347 pg/mL p<0.001 and p<0.003). Evaluation of BNP using Gensini Score showed a strong relation between BNP and coronary disease extension (r=0.38 p<0.0001).This trend was maintained in all CAD groups (SA=r 0.54; UA r=0.36 NSTE-ACS r=0.28). CONCLUSIONS: Circulating BNP levels appear elevated in ACS with diffuse coronary involvement, even in the absence of systolic dysfunction. BNP is also associated with multi-vessel disease and the extension of coronary disease

    AntarctiCor: Solar Coronagraph in Antarctica for the ESCAPE Project

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    The Antarctica solar coronagraph –AntarctiCor– for the “Extreme Solar Coronagraphy Antarctic Program Experiment” –ESCAPE– comprises an internally-occulted coronagraph based on the externally-occulted ASPIICS coronagraph for the ESA formation-flying PROBA-3 mission. This paper describes the AntarctiCor design for ground-based observations from the DomeC Antarctica plateau of the polarized broad-band (591 nm ± 5 nm) K-corona and of the narrowband (FWHM = 0.5 nm), polarized emission of the coronal green-line at 530.3 nm. The science goal of these observations is to map the topology and dynamics of the coronal magnetic field, addressing coronal heating and space weather questions

    International survey of COVID-19 management strategies

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    Background: While individual countries have gained considerable knowledge and experience in coronavirus disease of 2019 (COVID-19) management, an international, comparative perspective is lacking, particularly regarding the measures taken by different countries to tackle the pandemic. This paper elicits the views of health system staff, tapping into their personal expertise on how the pandemic was initially handled. Methods: From May to July 2020, we conducted a cross-sectional, online, purpose-designed survey comprising 70 items. Email lists of contacts provided by the International Society for Quality in Health Care, the Italian Network for Safety in Health Care and the Australian Institute of Health Innovation were used to access healthcare professionals and managers across the world. We snowballed the survey to individuals and groups connected to these organizations. Key outcome measures were attitudes and information about institutional approaches taken; media communication; how acute hospitals were re-organized; primary health organization; personal protective equipment; and staffing and training. Results: A total of 1131 survey participants from 97 countries across the World Health Organization (WHO) regions responded to the survey. Responses were from all six WHO regions; 57.9% were female and the majority had 10 or more years of experience in healthcare; almost half (46.5%) were physicians; and all other major clinical professional groups participated. As the pandemic progressed, most countries established an emergency task force, developed communication channels to citizens, organized health services to cope and put in place appropriate measures (e.g. pathways for COVID-19 patients, and testing, screening and tracing procedures). Some countries did this better than others. We found several significant differences between the WHO regions in how they are tackling the pandemic. For instance, while overall most respondents (71.4%) believed that there was an effective plan prior to the outbreak, this was only the case for 31.9% of respondents from the Pan American Health Organization compared with 90.7% of respondents from the South-East Asia Region (SEARO). Issues with swab testing (e.g. delay in communicating the swab outcome) were less frequently reported by respondents from SEARO and the Western Pacific Region compared with other regions. Conclusion: The world has progressed in its knowledge and sophistication in tackling the pandemic after early and often substantial obstacles were encountered. Most WHO regions have or are in the process of responding well, although some countries have not yet instituted widespread measures known to support mitigation, for example, effective swab testing and social control measures

    Origins of the slow and the ubiquitous fast solar wind

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    We present in this Letter the first coordinated radio occultation measurements and ultraviolet observations of the inner corona below 5.5 Rs, obtained during the Galileo solar conjunction in January 1997, to establish the origin of the slow solar wind. Limits on the flow speed are derived from the Doppler dimming of the resonantly scattered componentof the oxygen 1032 A and 1037 A lines as measured with the UltraViolet Coronagraph Spectrometer (UVCS) on the Solar and Heliospheric Observatory (SOHO). White light images of the corona from the Large Angle Spectroscopic Coronagraph (LASCO) on SOHO taken simultaneously are used to place the Doppler radio scintillation and ultraviolet measurements in the context ofcoronal structures. These combined observations provide the first direct confirmation of the view recently proposed by Woo and Martin (1997) that the slow solar wind is associated with the axes, also known as stalks, of streamers. Furthermore, the ultraviolet observations also show how the fast solar wind is ubiquitous in the inner corona, and that a velocity shear between the fast and slow solar wind develops along the streamer stalks.Comment: 15 pages, LaTex, 6 jpg figures, accepted Aug. 28, 1997 for publication in the ApJ Letter

    Design and Fabrication of the All-Reflecting H-Lyman alpha Coronagraph/Polarimeter

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    We have designed, analyzed, and are now fabricating an All-Reflecting H-Lyman alpha Coronagraph/Polarimeter for solar research. This new instrument operates in a narrow bandpass centered at lambda 1215.7 A-the neutral hydrogen Lyman alpha (Ly-alpha) line. It is shorter and faster than the telescope which produced solar Ly-alpha images as a part of the MSSTA payload that was launched on May 13, 1991. The Ly-alpha line is produced and linearly polarized in the solar corona by resonance scattering, and the presence of a magnetic field modifies this polarization according to the Hanle effect. The Lyman alpha Coronagraph/Polarimeter instrument has been designed to measure coronal magnetic fields by interpreting, via the Hanle effect, the measured linear polarization of the coronal Ly-alpha line. Ultrasmooth mirrors, polarizers, and filters are being flow-polished for this instrument from CVD silicon carbide substrates. These optical components will be coated using advanced induced transmission and absorption thin film multilayer coatings, to optimize the reflectivity and polarization properties at 1215.7 A. We describe some of the solar imaging results obtained with the MSSTA Lyman alpha coronagraph. We also discuss the optical design parameters and fabrication plans for the All-Reflecting H-Lyman alpha Coronagraph/Polarimeter

    Narrow genetic base in forest restoration with holm oak (Quercus ilex L.) in Sicily

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    In order to empirically assess the effect of actual seed sampling strategy on genetic diversity of holm oak (Quercus ilex) forestations in Sicily, we have analysed the genetic composition of two seedling lots (nursery stock and plantation) and their known natural seed origin stand by means of six nuclear microsatellite loci. Significant reduction in genetic diversity and significant difference in genetic composition of the seedling lots compared to the seed origin stand were detected. The female and the total effective number of parents were quantified by means of maternity assignment of seedlings and temporal changes in allele frequencies. Extremely low effective maternity numbers were estimated (Nfe \approx 2-4) and estimates accounting for both seed and pollen donors gave also low values (Ne \approx 35-50). These values can be explained by an inappropriate forestry seed harvest strategy limited to a small number of spatially close trees

    Coronal Diagnostics from Narrowband Images around 30.4 nm

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    Images taken in the band centered at 30.4 nm are routinely used to map the radiance of the He II Ly alpha line on the solar disk. That line is one of the strongest, if not the strongest, line in the EUV observed in the solar spectrum, and one of the few lines in that wavelength range providing information on the upper chromosphere or lower transition region. However, when observing the off-limb corona the contribution from the nearby Si XI 30.3 nm line can become significant. In this work we aim at estimating the relative contribution of those two lines in the solar corona around the minimum of solar activity. We combine measurements from CDS taken in August 2008 with temperature and density profiles from semiempirical models of the corona to compute the radiances of the two lines, and of other representative coronal lines (e.g., Mg X 62.5 nm, Si XII 52.1 nm). Considering both diagnosed quantities from line ratios (temperatures and densities) and line radiances in absolute units, we obtain a good overall match between observations and models. We find that the Si XI line dominates the He II line from just above the limb up to ~2 R_Sun in streamers, while its contribution to narrowband imaging in the 30.4 nm band is expected to become smaller, even negligible in the corona beyond ~2 - 3 R_Sun, the precise value being strongly dependent on the coronal temperature profile.Comment: 26 pages, 11 figures; to be published in: Solar Physic
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