149 research outputs found

    Control of fluctuations in ECR plasma by applying multipole magnetic fields

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    The control of fluctuations generated in an electron cyclotron resonance (ECR) plasma is attempted by changing microwave powers. It is found that when a cage is introduced in the vacuum chamber, the fluctuations change from turbulent state to chaotic state in the high microwave power region while it changes from chaotic state to periodic state in the low microwave power region. This result suggests that the geometry of the cage affects the state of the instability. Moreover it is found that the superposition of multicusped fields created by small permanent magnets reduces the chaotic dimension of the instability. When pulsed multipole magnetic fields are also added to external magnetic fields, the fluctuations are suppressed.Comment: 12th International Congress on Plasma Physics, 25-29 October 2004, Nice (France

    Conductance fluctuations in the presence of spin scattering

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    Electron transport through disordered systems that include spin scatterers is studied numerically. We consider three kinds of magnetic impurities: the Ising, the XY and the Heisenberg. By extending the transfer matrix method to include the spin degree of freedom, the two terminal conductance is calculated. The variance of conductance is halved as the number of spin components of the magnetic impurities increases. Application of the Zeeman field in the lead causes a further halving of the variance under certain conditions.Comment: to be published in Phys. Rev.

    IL-2 Protects Lupus-Prone Mice from Multiple End-Organ Damage by Limiting CD4 − CD8 − IL-17–Producing T Cells

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    Interleukin-2 (IL-2), a cytokine with pleiotropic effects, is critical for immune cell activation and peripheral tolerance. Although the therapeutic potential of IL-2 has been previously suggested in autoimmune diseases, the mechanisms whereby IL-2 mitigates autoimmunity and prevents organ damage remains unclear. Using an inducible recombinant adeno-associated virus (rAAV) vector we investigated the effect of low systemic levels of IL-2 in lupus-prone MRL/Faslpr/lpr (MRL/lpr) mice. Treatment of mice after the onset of disease with IL-2-rAAV resulted in reduced mononuclear cell infiltration and pathology of various tissues including skin, lungs and kidneys. In parallel, we noted a significant decrease of IL-17-producing CD3+CD4−CD8− double-negative T cells and an increase in CD4+CD25+Foxp3+ immunoregulatory T cells (Treg) in the periphery. We also show that IL-2 can drive DN T cell death through an indirect mechanism. Notably, targeted delivery of IL-2 to CD122+ cytotoxic lymphocytes effectively reduced the number of DN T cells and lymphadenopathy whereas selective expansion of Treg by IL-2 had no effect on DN T cells. Collectively, our data suggest that administration of IL-2 to lupus-prone mice protects against end-organ damage and suppresses inflammation by dually limiting IL-17-producing DN T cells and expanding Treg

    Practical "1-2-3-4-Day" Rule for Starting Direct Oral Anticoagulants After Ischemic Stroke With Atrial Fibrillation: Combined Hospital-Based Cohort Study

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    BACKGROUND: The "1-3-6-12-day rule" for starting direct oral anticoagulants (DOACs) in patients with nonvalvular atrial fibrillation after acute ischemic stroke or transient ischemic attack recommends timings that may be later than used in clinical practice. We investigated more practical optimal timing of DOAC initiation according to stroke severity. METHODS: The combined data of prospective registries in Japan, Stroke Acute Management with Urgent Risk-factor Assessment and Improvement-nonvalvular atrial fibrillation (September 2011 to March 2014) and RELAXED (February 2014 to April 2016) were used. Patients were divided into transient ischemic attack and 3 stroke subgroups by the National Institutes of Health Stroke Scale score: mild (0-7), moderate (8-15), and severe (≥16). The early treatment group was defined as patients starting DOACs earlier than the median initiation day in each subgroup. Outcomes included a composite of recurrent stroke or systemic embolism, ischemic stroke, and severe bleeding within 90 days. Six European prospective registries were used for validation. RESULTS: In the 1797 derivation cohort patients, DOACs were started at median 2 days after transient ischemic attack and 3, 4, and 5 days after mild, moderate, and severe strokes, respectively. Stroke or systemic embolism was less common in Early Group (n=785)-initiating DOACS within 1, 2, 3, and 4 days, respectively-than Late Group (n=1012) (1.9% versus 3.9%; adjusted hazard ratio, 0.50 [95% CI, 0.27-0.89]), as was ischemic stroke (1.7% versus 3.2%, 0.54 [0.27-0.999]). Major bleeding was similarly common in the 2 groups (0.8% versus 1.0%). On validation, both ischemic stroke (2.4% versus 2.2%) and intracranial hemorrhage (0.2% versus 0.6%) were similarly common in Early (n=547) and Late (n=1483) Groups defined using derivation data. CONCLUSIONS: In Japanese and European populations, early DOAC initiation within 1, 2, 3, or 4 days according to stroke severity seemed to be feasible to decrease the risk of recurrent stroke or systemic embolism and no increase in major bleeding. These findings support ongoing randomized trials to better establish the optimal timing of DOAC initiation

    Promotion of Secondary School Science Education Driven by Inquiry-Based Activity

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    This article reports fundamental researches organized for developing a novel teaching/learning system in secondary school science. A curriculum constructed by an effective integration of content-based and context-based curriculum arrangements is proposed for generating teaching/learning opportunities through various inquiry-based activities on the basis of previously acquired science knowledge and concepts. The science subjects, including physics, chemistry, biology and earth science, have different logics and methodologies of science, but those are completed by mutual interdependences. Therefore, various storylines that cover different leraning contents in science subjects can be developed. The inquiry-based activities along different storylines provide students with opportunities to correlate previous learnings in different science subjects and to experience various cognitive and scientific skills. Based on such findings of our basic researches, the merits of the science education system proposed in this study is discussed briefly.本研究は,科学研究費補助金基盤研究(A)(一般)(25242015)による
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