412 research outputs found

    Heliophysics Event Knowledgebase for the Solar Dynamics Observatory and Beyond

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    The immense volume of data generated by the suite of instruments on SDO requires new tools for efficient identifying and accessing data that is most relevant to research investigations. We have developed the Heliophysics Events Knowledgebase (HEK) to fill this need. The HEK system combines automated data mining using feature-detection methods and high-performance visualization systems for data markup. In addition, web services and clients are provided for searching the resulting metadata, reviewing results, and efficiently accessing the data. We review these components and present examples of their use with SDO data.Comment: 17 pages, 4 figure

    Is there something of the MCT in orientationally disordered crystals ?

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    Molecular Dynamics simulations have been performed on the orientationally disordered crystal chloroadamantane: a model system where dynamics are almost completely controlled by rotations. A critical temperature T_c = 225 K as predicted by the Mode Coupling Theory can be clearly determined both in the alpha and beta dynamical regimes. This investigation also shows the existence of a second remarkable dynamical crossover at the temperature T_x > T_c consistent with a previous NMR and MD study [1]. This allows us to confirm clearly the existence of a 'landscape-influenced' regime occurring in the temperature range [T_c-T_x] as recently proposed [2,3].Comment: 4 pages, 5 figures, REVTEX

    Topology Optimization and Characterization of Ti6Al4V ELI Cellular Lattice Structures by Laser Powder Bed Fusion for Biomedical Applications

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    Published ArticleTopology optimization approach was used for the design of Ti6Al4V ELI lattice structures with stiffness and density close to the human bone for implant applications. Three lattice designs with volume densities of 35 %, 40 % and 45 % and corresponding elastic modulus of 18.6 GPa, 23.1 GPa 27.4 GPa close to the human bone were generated. Laser powder bed fusion (LPBF) technique was used for the manufacturing of the specimens. Physical measurements and mechanical characterization of specimens were assessed by microCT analyses and compression test, perpendicular and parallel to the building direction of the specimens. LPBF Ti6Al4V ELI manufactured lattice structures showed deviations in wall thickness in comparison with the generated designs, leading to an increase in relative porosity but also a decrease in elastic modulus in comparison with the original designs. Horizontal walls of the lattice structures showed higher wall thickness in comparison with the vertical walls, leading to anisotropic behaviour of the lattice structures. Higher elastic modulus and compression strength were obtained when thicker walls were oriented along the loading direction of the compression test, showing a complete failure by dividing the specimens into two neighbouring halves. All specimens showed 45° diagonal shear fracture along the structure. On the other hand, higher energy absorption at first maximum compression strength peak was observed when samples were tested parallel to the building direction (when thinner walls were oriented along the loading compression direction). Results showed that designed lattice structures can possess the levels of human bones’ stiffness and therefore can reduce/avoid stress shielding on implant applications

    Evidence for energy injection and a fine-tuned central engine at optical wavelengths in GRB 070419A

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    We present a comprehensive multiwavelength temporal and spectral analysis of the FRED GRB 070419A. The early-time emission in the γ\gamma-ray and X-ray bands can be explained by a central engine active for at least 250 s, while at late times the X-ray light curve displays a simple power-law decay. In contrast, the observed behaviour in the optical band is complex (from 102^2 up to 106^6 s). We investigate the light curve behaviour in the context of the standard forward/reverse shock model; associating the peak in the optical light curve at \sim450 s with the fireball deceleration time results in a Lorenz factor Γ350\Gamma \approx 350 at this time. In contrast, the shallow optical decay between 450 and 1500 s remains problematic, requiring a reverse shock component whose typical frequency is above the optical band at the optical peak time for it to be explained within the standard model. This predicts an increasing flux density for the forward shock component until t \sim 4 ×\times 106^6 s, inconsistent with the observed decay of the optical emission from t \sim 104^4 s. A highly magnetized fireball is also ruled out due to unrealistic microphysic parameters and predicted light curve behaviour that is not observed. We conclude that a long-lived central engine with a finely tuned energy injection rate and a sudden cessation of the injection is required to create the observed light curves - consistent with the same conditions that are invoked to explain the plateau phase of canonical X-ray light curves of GRBs.Comment: 9 pages, 10 figures, accepted for publication in MNRA

    Pleural aspergillosis complicated by recurrent pneumothorax: a case report

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    <p>Abstract</p> <p>Introduction</p> <p>Pneumothorax as the first symptom of pleural aspergillosis is rare.</p> <p>Case presentation</p> <p>A 31-year-old asthmatic Chinese man presented with recurrent spontaneous pneumothorax and underwent lobectomy due to persistent air leakage. Aspergillus was detected histopathologically in the visceral pleural cavity. He was treated with itraconazole at 200 mg a day, and nine months later he had no recurrent pneumothorax or aspergillus infection.</p> <p>Conclusion</p> <p>Recurrent pneumothorax may be a rare manifestation of aspergillus infection. Aspergillus species infection should be considered in the differential diagnosis of recurrent pneumothorax patients, particularly those with chronic lung disease.</p

    Chacterization of CU tube filled with Al alloy foam by means of X-ray computer tomography

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    Copper tubes filled with aluminium foams were prepared by directly foaming metal powder compacts inside them. Compressive behaviour and foam-shell interface, that characterizes mechanical properties of reinforced tubes, were investigated by means of variable focus X-ray computer tomography. Compression tests were performed on empty and filled samples at increasing deformation steps: at each stage the samples were observed by tomography. A geometric evaluation of porosity on 2D sections was performed by calculating, for each pore, its area, equivalent diameter and circularity

    Comparison of T-Cell Interferon-γ Release Assays for Mycobacterium tuberculosis-Specific Antigens in Patients with Active and Latent Tuberculosis

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    Through the use of QuantiFERON-TB Gold, a commercial IFN-γ assay, we compared differences in quantitative T-cell responses to Mycobacterium tuberculosis (MTB)-specific antigens [QuantiFERON TB-2G (QFT-2G)] between patients with active tuberculosis (TB) disease and those with latent TB infection (LTBI). The patient group consisted of 180 patients with active TB disease (culture-positive for MTB) and 50 screening contacts with LTBI-positive response to the QFT-2G test. We prospectively performed a tuberculin skin test (TST) and a QFT-2G test for all subjects. The median IFN-γ levels upon the application of both antigens, ESAT-6 and CFP-10, were significantly higher in patients with active TB disease than in those with LTBI. A combined positive response to both antigens occurred at a higher rate in patients with active TB disease than in those with LTBI. There were no significant relationships between the quantitative responses of IFN-γ to both antigens and the maximum induration on TST in both patient groups. We demonstrated significant differences in the quantitative responses of IFN-γ to MTB between patients with active TB disease and those with LTBI in this study. However, there was an overlap in the IFN-γ levels between active TB disease and LTBI groups. Therefore, it would be difficult to use the QFT-2G test to completely discriminate active TB disease from LTBI
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