27 research outputs found

    Double‐probe measurement in recombining plasma using NAGDIS‐II

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    We have studied the validity of the double-probe method in recombining plasmas. Electron temperature (Te) measured with a double probe was quantitatively evaluated by taking into account the influences of plasma potential fluctuation, plasma resistivity, and electron density fluctuation on the current–voltage characteristics. Differential potential fluctuation and plasma resistivity between two electrodes have a minor effect on Te especially when the inter-distance is small (typically 1 mm). Scattering of measured Te due to the density fluctuation was sufficiently suppressed by making the data acquisition time long (typically 4 s) and taking the average. There is a good agreement between Te measured with the optimized double-probe method and that with laser Thomson scattering diagnostics

    The Runx1 Transcription Factor Inhibits the Differentiation of Naive CD4+ T Cells into the Th2 Lineage by Repressing GATA3 Expression

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    Differentiation of naive CD4+ T cells into helper T (Th) cells is controlled by a combination of several transcriptional factors. In this study, we examined the functional role of the Runx1 transcription factor in Th cell differentiation. Naive T cells from transgenic mice expressing a dominant interfering form of Runx1 exhibited enhanced interleukin 4 production and efficient Th2 differentiation. In contrast, transduction of Runx1 into wild-type T cells caused a complete attenuation of Th2 differentiation and was accompanied by the cessation of GATA3 expression. Furthermore, endogenous expression of Runx1 in naive T cells declined after T cell receptor stimulation, at the same time that expression of GATA3 increased. We conclude that Runx1 plays a novel role as a negative regulator of GATA3 expression, thereby inhibiting the Th2 cell differentiation

    Overview of transport and MHD stability study: focusing on the impact of magnetic field topology in the Large Helical Device

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    The progress in the understanding of the physics and the concurrent parameter extension in the large helical device since the last IAEA-FEC, in 2012 (Kaneko O et al 2013 Nucl. Fusion 53 095024), is reviewed. Plasma with high ion and electron temperatures (Ti(0) ~ Te(0) ~ 6 keV) with simultaneous ion and electron internal transport barriers is obtained by controlling recycling and heating deposition. A sign flip of the nondiffusive term of impurity/momentum transport (residual stress and convection flow) is observed, which is associated with the formation of a transport barrier. The impact of the topology of three-dimensional magnetic fields (stochastic magnetic fields and magnetic islands) on heat momentum, particle/impurity transport and magnetohydrodynamic stability is also discussed. In the steady state operation, a 48 min discharge with a line-averaged electron density of 1 × 1019 m−3 and with high electron and ion temperatures (Ti(0) ~ Te(0) ~ 2 keV), resulting in 3.36 GJ of input energy, is achieved

    Role of sphingosine 1-phosphate (S1P) and effects of fingolimod, an S1P receptor 1 functional antagonist in lymphocyte circulation and autoimmune diseases

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    Sphingosine 1-phosphate (S1P), a multi-functional phospholipid mediator, is generated from sphingosine by sphingosine kinases and binds to five known G protein-coupled S1P receptors (S1P1, S1P2, S1P3, S1P4, and S1P5). It is widely accepted that S1P receptor 1 (S1P1) plays an essential role in lymphocyte egress from the secondary lymphoid organs (SLO) and thymus, because lymphocyte egress from these organs to periphery is at extremely low levels in mice lacking lymphocytic S1P1. Fingolimod hydrochloride (FTY720) is a first-in-class, orally active S1P1 functional antagonist which was discovered by chemical modification of a natural product, myriocin. Since FTY720 has a structure closely related to sphingosine, the phosphorylated FTY720 (FTY720-P) is converted by sphingosine kinases and binds 4 types of S1P receptors. FTY720-P strongly induces down-regulation of S1P1 by internalization and degradation of this receptor and acts as a functional antagonist at S1P1. Consequently, FTY720 inhibits S1P1-dependent lymphocyte egress from the SLO and thymus to reduce circulating lymphocytes including autoreactive Th17 cells, and is highly effective in experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis (MS). In relapsing remitting MS patients, oral FTY720 shows a superior efficacy when compared to intramuscular interferon-β-1a. Based on these data, it is presumed that modulation of the S1P-S1P1 axis provides an effective therapy for autoimmune diseases including MS
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