912 research outputs found
Doppler shift of hot coronal lines in a moss area of an active region
The moss is the area at the footpoint of the hot (3 to 5 MK) loops forming
the core of the active region where emission is believed to result from the
heat flux conducted down to the transition region from the hot loops. Studying
the variation of Doppler shift as a function of line formation temperatures
over the moss area can give clues on the heating mechanism in the hot loops in
the core of the active regions. We investigate the absolute Doppler shift of
lines formed at temperatures between 1 MK and 2 MK in a moss area within active
region NOAA 11243 using a novel technique that allows determining the absolute
Doppler shift of EUV lines by combining observations from the SUMER and EIS
spectrometers. The inner (brighter and denser) part of the moss area shows
roughly constant blue shift (upward motions) of 5 km/s in the temperature range
of 1 MK to 1.6 MK. For hotter lines the blue shift decreases and reaches 1 km/s
for Fe xv 284 {\AA} (~2 MK). The measurements are discussed in relation to
models of the heating of hot loops. The results for the hot coronal lines seem
to support the quasi-steady heating models for non-symmetric hot loops in the
core of active regions.Comment: 11 pages, 15 Figures, Astronomy and Astrophysics (in press
Deep Multi-view Models for Glitch Classification
Non-cosmic, non-Gaussian disturbances known as "glitches", show up in
gravitational-wave data of the Advanced Laser Interferometer Gravitational-wave
Observatory, or aLIGO. In this paper, we propose a deep multi-view
convolutional neural network to classify glitches automatically. The primary
purpose of classifying glitches is to understand their characteristics and
origin, which facilitates their removal from the data or from the detector
entirely. We visualize glitches as spectrograms and leverage the
state-of-the-art image classification techniques in our model. The suggested
classifier is a multi-view deep neural network that exploits four different
views for classification. The experimental results demonstrate that the
proposed model improves the overall accuracy of the classification compared to
traditional single view algorithms.Comment: Accepted to the 42nd IEEE International Conference on Acoustics,
Speech and Signal Processing (ICASSP'17
Systematic assessment of HER2/neu in gynecologic neoplasms, an institutional experience.
BackgroundHER2/neu overexpression and/or amplification has been widely studied in a number of solid tumors, primarily in the breast. In gynecologic neoplasms, determination of HER2/neu status has not been well studied as a predictive biomarker in anti-HER2/neu treatment.MethodsWe systematically evaluated the HER2/neu reactions by immunohistochemistry and fluorescent in situ hybridization in malignant gynecologic neoplasms as experienced in our institution.ResultsThe HER2/neu overexpression or amplification occurred in 8 % of the cancers of the gynecological organs in our series. Majority of the HER2/neu overexpression and/or amplification occurred in clear cell (27 %) and serous (11 %) carcinomas. HER2/neu positivity was also seen in undifferentiated as well as in mixed clear cell and serous carcinomas. Discordant IHC and FISH results (positive by FISH but not IHC) was seen in 2 cases. Majority of the HER2/neu overexpression and/or amplification occurs in the endometrium rather than the ovary. Heterogeneity of the HER2/neu by IHC staining was in < 2 % of the tumors in our series.ConclusionsWe recommend the HER2/neu studies on Müllerian carcinomas of clear cell, serous, and undifferentiated types, particularly when they arise in the endometrium. Since there are some discordant IHC/FISH results, we also propose performing the HER2/neu testing by FISH when the IHC score is less than 3 + 
Evaluation of myeloid-derived suppressor cells in the blood of Iranian COVID-19 patients
The cytokine storm and lymphopenia are reported in coronavirus disease 2019 (COVID-19). Myeloid-derived suppressive cells (MDSCs) exist in two different forms, granulocyte (G-MDSCs) and monocytic (M-MDSCs), that both suppress T-cell function. In COVID-19, the role of chemokines such as interleukin (IL)-8 in recruiting MDSCs is unclear. A recent report has correlated IL-8 and MDSCs with poor clinical outcomes in melanoma patients. In the current study, we evaluated the frequency of MDSCs and their correlation with serum IL-8 levels in severe COVID-19 patients from Iran. Thirty-seven severe patients (8 on ventilation, 29 without ventilation), thirteen moderate COVID-19 patients, and eight healthy subjects participated in this study between 10th April 2020 and 9th March 2021. Clinical and biochemical features, serum, and whole blood were obtained. CD14, CD15, CD11b, and HLA-DR expression on MDSCs was measured by flow cytometry. COVID-19 patients compared to healthy subjects had a greater frequency of M-MDSCs (12.7±13.3% vs 0.19±0.20%,), G-MDSCs (15.8±12.6% vs 0.35±0.40%,) and total-MDSCs (27.5±17.3% vs 0.55±0.41%,). M-MDSC (16.8±15.8% vs 5.4±4.8%,) and total-MDSC (33.3±18.5% vs 17.3±13.3%) frequency was higher in non- ventilated compared to moderate COVID-19 subjects. Serum IL-8 levels were higher in patients with COVID-19 than in normal healthy subjects (6.4±7.8 vs. 0.10±00 pg/mL). Ventilated patients (15.7±6.7 pg/mL), non-ventilated patients (5.7±2.7 pg/mL) and moderate patients (2.8±3.0 pg/mL) had significantly different levels of IL-8.  A negative correlation was found between the frequency of G-MDSCs and the international normalized ratio (INR) test (r=-0.39), and between the frequency of total-MDSCs and oxygen saturation (%) (r=-0.39). COVID-19 patients with severe non-ventilated disease had the highest levels of M-MDSCs. In addition to systemic MDSCs, lung, serum IL-8, and other inflammatory biomarkers should be measured
Collective dynamics of two-mode stochastic oscillators
We study a system of two-mode stochastic oscillators coupled through their
collective output. As a function of a relevant parameter four qualitatively
distinct regimes of collective behavior are observed. In an extended region of
the parameter space the periodicity of the collective output is enhanced by the
considered coupling. This system can be used as a new model to describe
synchronization-like phenomena in systems of units with two or more oscillation
modes. The model can also explain how periodic dynamics can be generated by
coupling largely stochastic units. Similar systems could be responsible for the
emergence of rhythmic behavior in complex biological or sociological systems.Comment: 4 pages, RevTex, 5 figure
Evidence for Suzuki–Miyaura cross-couplings catalyzed by ligated Pd3-clusters: from cradle to grave
Pdn clusters offer unique selectivity and exploitable reactivity in catalysis. Understanding the behavior of Pdn clusters is thus critical for catalysis, applied synthetic organic chemistry and greener outcomes for precious Pd. The Pd3 cluster, [Pd3(μ-Cl)(μ-PPh2)2(PPh3)3][Cl] (denoted as Pd3Cl2), which exhibits distinctive reactivity, was synthesized and immobilized on a phosphine-functionalized polystyrene resin (denoted as immob-Pd3Cl2). The resultant material served as a tool to study closely the role of Pd3 clusters in a prototypical Suzuki–Miyaura cross-coupling of 4-fluoro-1-bromobenzene and 4-methoxyphenyl boronic acid at varying low Pd ppm concentrations (24, 45, and 68 ppm). Advanced heterogeneity tests such as Hg poisoning and the three-phase test showed that leached mononuclear or nanoparticulate Pd are unlikely to be the major active catalyst species under the reaction conditions tested. EXAFS/XANES analysis from (pre)catalyst and filtered catalysts during and after catalysis has shown the intactness of the triangular structure of the Pd3X2 cluster, with exchange of chloride (X) by bromide during catalytic turnover of bromoarene substrate. This finding is further corroborated by treatment of immob-Pd3Cl2 after catalyzing the Suzuki–Miyaura reaction with excess PPh3, which releases the cluster from the polymer support and so permits direct observation of [Pd3(μ-Br)(μ-PPh2)2(PPh3)3]+ ions by ESI-MS. No evidence is seen for a proposed intermediate in which the bridging halogen on the Pd3 motif is replaced by an aryl group from the organoboronic acid, i.e. formed by a transmetallation-first process. Our findings taken together indicate that the ‘Pd3X2’ motif is an active catalyst species, which is stabilized by being immobilized, providing a more robust Pd3 cluster catalyst system. Non-immobilized Pd3Cl2 is less stable, as is followed by stepwise XAFS of the non-immobilized Pd3Cl2, which gradually changes to a species consistent with ‘Pdx(PPh3)y’ type material. Our findings have far-reaching future implications for Pd3 cluster involvement in catalysis, showing that immobilization of Pd3 cluster species offers advantages for rigorous mechanistic examination and applied chemistries
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