18 research outputs found

    A Time Domain Volume Integral Equation Solver to Analyze Electromagnetic Scattering from Nonlinear Dielectric Objects

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    A time domain electric field volume integral equation (TD-EFVIE) solver is proposed for analyzing electromagnetic scattering from dielectric objects with Kerr nonlinearity. The nonlinear constitutive relation that relates electric flux and electric field induced in the scatterer is used as an auxiliary equation that complements TD-EFVIE. The ordinary differential equation system that arises from TD-EFVIE's Schaubert-Wilton-Glisson (SWG)-based discretization is integrated in time using a PE(CE)m scheme for the unknown expansion coefficients of the electric field. Matrix systems that arise from the SWG-based discretization of the nonlinear constitutive relation and its inverse obtained using the Pade approximant are used to carry out explicit updates of electric field and electric flux expansion coefficients at the predictor (PE) and the corrector (CE) stages. The resulting explicit marching-on-in-time (MOT) scheme does not call for any Newton-like nonlinear solver and only requires solution of sparse and well-conditioned Gram matrix systems at every step. Numerical results show that the proposed explicit MOT-based TD-EFVIE solver is more accurate than the finite-difference time-domain method that is traditionally used for analyzing transient electromagnetic scattering from nonlinear objects

    On the mixed discretization of the time domain magnetic field integral equation

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    International audienceTime domain magnetic field integral equation (MFIE) is discretized using divergence-conforming Rao-Wilton-Glisson (RWG) and curl-conforming Buffa-Christiansen (BC) functions as spatial basis and testing functions, respectively. The resulting mixed discretization scheme, unlike the classical scheme which uses RWG functions as both basis and testing functions, is “proper”: Testing functions belong to dual space of the basis functions. Numerical results demonstrate that the marching on-in-time (MOT) solution of the mixed discretized MFIE yields more accurate results than that of classically discretized MFIE

    TRAIL Death Receptor-4, Decoy Receptor-1 and Decoy Receptor-2 Expression on CD8+ T Cells Correlate with the Disease Severity in Patients with Rheumatoid Arthritis

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    BACKGROUND: Rheumatoid Arthritis (RA) is a chronic autoimmune inflammatory disorder. Although the pathogenesis of disease is unclear, it is well known that T cells play a major role in both development and perpetuation of RA through activating macrophages and B cells. Since the lack of TNF-Related Apoptosis Inducing Ligand (TRAIL) expression resulted in defective thymocyte apoptosis leading to an autoimmune disease, we explored evidence for alterations in TRAIL/TRAIL receptor expression on peripheral T lymphocytes in the molecular mechanism of RA development. METHODS: The expression of TRAIL/TRAIL receptors on T cells in 20 RA patients and 12 control individuals were analyzed using flow cytometry. The correlation of TRAIL and its receptor expression profile was compared with clinical RA parameters (RA activity scored as per DAS28) using Spearman Rho Analysis. RESULTS: While no change was detected in the ratio of CD4+ to CD8+ T cells between controls and RA patient groups, upregulation of TRAIL and its receptors (both death and decoy) was detected on both CD4+ and CD8+ T cells in RA patients compared to control individuals. Death Receptor-4 (DR4) and the decoy receptors DcR1 and DcR2 on CD8+ T cells, but not on CD4+ T cells, were positively correlated with patients' DAS scores. CONCLUSIONS: Our data suggest that TRAIL/TRAIL receptor expression profiles on T cells might be important in revelation of RA pathogenesis

    Year 2015: the moment of truth for the “Resolution Process” of the Kurdish issue in Turkey

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    Since its foundation, on 26 November 1978, in the remote village of Fis in Turkey’s Lice province, the ethnic-secessionist PKK, also known as Kurdish Workers’ Party (Partiya Karkeren Kurdistan), a terrorist organization, had its tidal phases throughout three decades and managed to transform itself in line with the conjuncture. It has first sought to fight for Kurdish people’s cultural and social rights and freedoms, then to set up an autonomous Kurdish administration within Turkey, brought together under the framework of “democratic confederalism”. In the Middle East, where nation states can no longer sustain, the only convenient solution would be a pyramid-based organization of democratic confederalism (Öcalan, 2004:28). PKK’s ultimate goal is to free and unite the Kurdish people living separately in the four parts (Turkey, Iraq, Syria and Iran) of Greater Kurdistan and find itself a passage to Mediterranean Sea

    A Surface Integral Equation Solver for Transient Analysis of Graphene Devices

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    A surface integral equation solver for analyzing transient electromagnetic wave interactions on composite graphene-based devices is described. The time domain resistive boundary condition (TD-RBC) and the Poggio-Miller-Chang-Harrington-Wu-Tsai (TD-PMCHWT) integral equation, which are enforced on the surfaces of the graphene and dielectric substrates, respectively, are discretized using the well-known marching-on-in-time (MOT) scheme. The expressions of the time domain resistivity and conductivity of the graphene sheet are obtained analytically from the intra-band contribution formulated in frequency domain

    Increased Levels of VEGF-A and HIF-1α in Turkish Children with Crimean-Congo Hemorrhagic Fever

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    Background: Crimean-Congo Hemorrhagic Fever (CCHF) is a disease characterized by serious course, including acute viral fever, ecchymosis, thrombocytopenia, liver dysfunction and high rate of mortality. Hypoxia Inducible Factor-1α (HIF-1α) and Vascular Endothelial Growth Factor-A (VEGF-A) play an important role both in the inflamma­tory process and plasma leakage. The aim of this study was to define HIF-1α and VEGF-A serum levels obtained from CCHF patients and control group and to investigate whether these factors were correlated with the pathogenesis of this disease. Methods: Thirty cases younger than 17 yr confirmed by RT-PCR and/or ELISA for CCHF were included in this study. Thirty age and sex matched healthy peoples were enrolled as controls. Blood samples collected from the pa­tient and control groups. Serum levels of HIF-1α and VEGF-A were measured with ELISA. Results: Levels of HIF-1α and VEGF-A were statistically significantly increased in CCHF patients compared to the control group (P< 0.05).  A significant positive correlation was found between the levels of HIF-1α and VEGF-A in the patient group (P< 0.01). The levels of ALT, AST, CK, aPTT, WBC and Thrombocyte count were significantly higher in the patients than in the control group (P< 0.001). A positive correlation was found among the levels of AST and CK from biochemical parame­ters and VEGF and HIF-1α in the patient group (P< 0.05) Conclusion: HIF-1α and VEGF-A might play an important role in CCHF pathogenesis
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