55 research outputs found

    Correction of SOHO CELIAS/SEM EUV Measurements saturated by extreme solar flare events

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    The solar irradiance in the Extreme Ultraviolet (EUV) spectral bands has been observed with a 15 sec cadence by the SOHO Solar EUV Monitor (SEM) since 1995. During remarkably intense solar flares the SEM EUV measurements are saturated in the central (zero) order channel (0.1 -- 50.0 nm) by the flare soft X-ray and EUV flux. The first order EUV channel (26 -- 34 nm) is not saturated by the flare flux because of its limited bandwidth, but it is sensitive to the arrival of Solar Energetic Particles (SEP). While both channels detect nearly equal SEP fluxes, their contributions to the count rate is sensibly negligible in the zero order channel but must be accounted for and removed from the first channel count rate. SEP contribution to the measured SEM signals usually follows the EUV peak for the gradual solar flare events. Correcting the extreme solar flare SEM EUV measurements may reveal currently unclear relations between the flare magnitude, dynamics observed in different EUV spectral bands, and the measured Earth atmosphere response. A simple and effective correction technique based on analysis of SEM count-rate profiles, GOES X-ray, and GOES proton data has been developed and used for correcting EUV measurements for the five extreme solar flare events of July 14, 2000, October 28, November 2, November 4, 2003, and January 20, 2005. Although none of the 2000 and 2003 flare peaks were contaminated by the presence of SEPs, the January 20, 2005 SEPs were unusually prompt and contaminated the peak. The estimated accuracy of the correction is about 7.5% for large X-class events.Comment: To appear in Astron. Nachr. /A

    Associations of IL17A G-197A single nucleotide polymorphism with immunological parameters and structural changes of the brain in schizophrenia

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    Schizophrenia is a chronic mental disorder that is caused by a complex palette of genetic, epigenetic and environmental factors. Some of the important components of its pathogenesis are systemic inflammation and the dysfunction of immunity, which lead to neuroinflammation, contributing to development of structural brain changes. Earlier we have shown that increase in interleukin-17A levels is associated with morphometric changes and immune dysregulation in schizophrenia. IL17A G-197A (rs2275913) genetic polymorphism is involved in determining interleukin-17A secretion. The goal of this work was to investigate the associations between rs2275913 polymorphism, immune disorders and structural neurovisualization findings in schizophrenia to provide new insights into the immunopathogenesis of this disease. 60 patients aged 18 to 42 years diagnosed with schizophrenia were enrolled. 85 healthy volunteers were included into the control group. Multiplex assay was used to determine cytokine and chemokine serum levels. Rs2275913 polymorphism was assessed by polymerase chain reaction with electrophoretic detection of amplification products. A number of relationships between rs2275913 polymorphism and the immune parameters in schizophrenia were revealed. Carriers of G allele showed significant increase in IFNY, a key cytokine of Th1-link of adaptive immunity, and IL-8, an inflammatory chemokine. Also, increased levels of CXCL16 were observed in patients carrying the G allele. CXCL16 activates secretion of other proinflammatory chemokines and is involved in activation of Th1 adaptive immunity. Associations of heterozygous GA genotype with reduced cortical thickness in a number of areas of the frontal cortex in schizophrenia were found. Changes in cortical thickness in some of these areas, including middle frontal gyrus and orbitofrontal cortex, can be relevant to the pathogenesis of schizophrenia. The results highlight the importance of immunogenetic factors in the pathogenesis of schizophrenia and indicate that the rs2275913 polymorphism requires further studies as a potential biomarker of immune dysregulation and morphometric brain changes in schizophrenia

    СЛУЧАЙ МНОЖЕСТВЕННЫХ ГЕНЕТИЧЕСКИХ НАРУШЕНИЙ В РАЗЛИЧНЫХ СИСТЕМАХ ЗАЩИТЫ ЛЕГКИХ

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    A case of multiple genetic lesions in different systems of the lung defenseСлучай множественных генетических нарушений в различных системах защиты легки

    Extreme Ultraviolet Variability Experiment (EVE) on the Solar Dynamics Observatory (SDO): Overview of Science Objectives, Instrument Design, Data Products, and Model Developments

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    The highly variable solar extreme ultraviolet (EUV) radiation is the major energy input to the Earth’s upper atmosphere, strongly impacting the geospace environment, affecting satellite operations, communications, and navigation. The Extreme ultraviolet Variability Experiment (EVE) onboard the NASA Solar Dynamics Observatory (SDO) will measure the solar EUV irradiance from 0.1 to 105 nm with unprecedented spectral resolution (0.1 nm), temporal cadence (ten seconds), and accuracy (20%). EVE includes several irradiance instruments: The Multiple EUV Grating Spectrographs (MEGS)-A is a grazing-incidence spectrograph that measures the solar EUV irradiance in the 5 to 37 nm range with 0.1-nm resolution, and the MEGS-B is a normal-incidence, dual-pass spectrograph that measures the solar EUV irradiance in the 35 to 105 nm range with 0.1-nm resolution. To provide MEGS in-flight calibration, the EUV SpectroPhotometer (ESP) measures the solar EUV irradiance in broadbands between 0.1 and 39 nm, and a MEGS-Photometer measures the Sun’s bright hydrogen emission at 121.6 nm. The EVE data products include a near real-time space-weather product (Level 0C), which provides the solar EUV irradiance in specific bands and also spectra in 0.1-nm intervals with a cadence of one minute and with a time delay of less than 15 minutes. The EVE higher-level products are Level 2 with the solar EUV irradiance at higher time cadence (0.25 seconds for photometers and ten seconds for spectrographs) and Level 3 with averages of the solar irradiance over a day and over each one-hour period. The EVE team also plans to advance existing models of solar EUV irradiance and to operationally use the EVE measurements in models of Earth’s ionosphere and thermosphere. Improved understanding of the evolution of solar flares and extending the various models to incorporate solar flare events are high priorities for the EVE team.United States. National Aeronautics and Space Administration (contract NAS5-02140

    Association of IL-17A levels with immuneinflammatory profile and structural MRI data in patients with schizophrenia

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    IL-17A is a proinflammatory cytokine involved in pathogenesis of some neuroinflammatory diseases of the brain. However, its role in schizophrenia is poorly understood. Currently, noninvasive neuroimaging techniques are widely used to assess abnormalities in brain morphology and interactions of neuronal networks in schizophrenia. The aim of this work was to study associations between IL-17A level and brain morphometric parameters in schizophrenia, in order to clarify immune factors of pathogenesis and search for biomarkers of unfavorable disease course. 45 patients with schizophrenia and 30 healthy volunteers were included into the study. The levels of cytokines (IL-5, IL-6, IL-8, IL-10, IL-17A) and inflammatory markers were determined by ELISA or multiplex analysis. MRI scans were performed with a Siemens Magnetom Verio 3T MRI scanner. We used Kruskal–Wallis test to assess significant differences in immunological parameters followed by Mann–Whitney paired comparison; Student test to assess the significance of differences in morphometric parameters of the brain; Fisher exact test to assess the differences in discrete variables, with the differences considered statistically significant at p < 0.05. IL-17A levels were found to be increased in schizophrenia. Its elevated content was associated with increased levels of C-reactive protein, IL-5, IL-6, IL-8, IL-10, and the presence of morphometric changes of frontal and temporal cortex in the patients. So far, the relationships between IL-17A levels, immunoinflammatory parameters and structural brain changes have not been studied in schizophrenia. In the present work, we found an association of elevated IL-17A levels with decreased cortical thickness in several brain regions, systemic inflammation and activation of Th2-link of adaptive immunity in the patients with schizophrenia. According to the literature, a number of brain areas, where cortical thickness was associated with IL-17A levels may be relevant to pathogenesis of the disease and, in particular, to the development of negative symptoms, including impoverishment of interests, speech, and emotions. The results are important for understanding the role of immune disorders in pathogenesis of schizophrenia, including structural changes of the brain, and suggest that IL-17A may be a biomarker of these disorders. Confirmation of associations between structural neuroimaging findings, laboratory markers of inflammation and immune disorders may provide the basis for new multidisciplinary approaches to the diagnosis and prognosis of schizophrenia

    On the Importance of the Flare's Late Phase for the Solar Extreme Ultraviolet Irradiance

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    The new solar extreme ultraviolet (EUV) irradiance observations from NASA Solar Dynamics Observatory (SDO) have revealed a new class of solar flares that are referred to as late phase flares. These flares are characterized by the hot 2-5 MK coronal emissions (e.g., Fe XVI 33.5 nm) showing large secondary peaks that appear many minutes to hours after an eruptive flare event. In contrast, the cool 0.7-1.5 MK coronal emissions (e.g., Fe IX 17.1 nm) usually dim immediately after the flare onset and do not recover until after the delayed second peak of the hot coronal emissions. We refer to this period of 1-5 hours after the fl amrea sin phase as the late phase, and this late phase is uniquely different than long duration flares associated with 2-ribbon flares or large filament eruptions. Our analysis of the late phase flare events indicates that the late phase involves hot coronal loops near the flaring region, not directly related to the original flaring loop system but rather with the higher post-eruption fields. Another finding is that space weather applications concerning Earth s ionosphere and thermosphere need to consider these late phase flares because they can enhance the total EUV irradiance flare variation by a factor of 2 when the late phase contribution is included
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