1,104 research outputs found

    The cushion region and dayside magnetodisc structure at Saturn

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    A sustained dipolar magnetic field between the current sheet outer edge and the magnetopause, known as a cushion region, has yet to be observed at Saturn. Whilst some signatures of reconnection occurring in the dayside magnetodisc have been identified, the presence of this large-scale structure has not been seen. Using the complete Cassini magnetometer data, the first evidence of a cushion region forming at Saturn is shown. Only five potential examples of a sustained cushion are found, revealing this phenomenon to be rare. This feature more commonly occurs at dusk compared to dawn, where it is found at Jupiter. It is suggested that due to greater heating and expansion of the field through the afternoon sector the disc is more unstable in this region. We show that magnetodisc breakdown is more likely to occur within the magnetosphere of Jupiter compared to Saturn

    Systemic mastocytosis with associated myeloproliferative disease and precursor B lymphoblastic leukaemia with t(13;13)(q12;q22) involving FLT3.

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    Systemic mastocytoses represent neoplastic proliferations of mast cells. In about 20% of cases systemic mastocytoses are accompanied by clonal haematopoietic non-mast cell-lineage disorders, most commonly myeloid neoplasms. A case of systemic mastocytosis carrying the characteristic mutation at codon 816 (D816V) in the KIT gene of mast cells, with two concurrent accompanying clonal haematopoietic non-mast cell-lineage disorders, chronic myeloproliferative disease, unclassifiable and precursor B lymphoblastic leukaemia is documented. Both accompanying clonal haematopoietic non-mast cell-lineage disorders carried the wild-type KIT gene, but had a novel t(13;13)(q12;q22) involving the FLT3 locus at 13q12. The chronic myeloproliferative disease, unclassifiable and the precursor B lymphoblastic leukaemia were cured by syngenous stem cell transplantation, but the systemic mastocytosis persisted for more than 10 years. The additional impact of molecular techniques on the correct diagnosis in haematological malignancies is highlighted, and evidence is provided that, apart from internal tandem duplications and mutations, FLT3 can be activated by translocations

    Electrical Control of Linear Dichroism in Black Phosphorus from the Visible to Mid-Infrared

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    The incorporation of electrically tunable materials into photonic structures such as waveguides and metasurfaces enables dynamic control of light propagation by an applied potential. While many materials have been shown to exhibit electrically tunable permittivity and dispersion, including transparent conducting oxides (TCOs) and III-V semiconductors and quantum wells, these materials are all optically isotropic in the propagation plane. In this work, we report the first known example of electrically tunable linear dichroism, observed here in few-layer black phosphorus (BP), which is a promising candidate for multi-functional, broadband, tunable photonic elements. We measure active modulation of the linear dichroism from the mid-infrared to visible frequency range, which is driven by anisotropic quantum-confined Stark and Burstein-Moss effects, and field-induced forbidden-to-allowed optical transitions. Moreover, we observe high BP absorption modulation strengths, approaching unity for certain thicknesses and photon energies

    Rare KIT (CD117) expression in multiple myeloma abrogates the usefulness of imatinib mesylate treatment

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    Background: Imatinib mesylate blocks the tyrosine kinase activity of KIT (CD117) and is an effective treatment for gastrointestinal stromal tumors. In multiple myeloma, KIT expression has been detected by flow cytometry in about 33% of specimens, but no previous immunohistochemical assessment has yet been made of the expression pattern of KIT. Materials and methods: We performed immunohistochemical analyses of 100 patients, including 72 with multiple myeloma (MM), 8 with lymphoplasmacytic lymphoma (LPL), 10 with monoclonal gammopathy of undetermined significance (MGUS) and 10 with reactive plasmocytosis. One KIT-positive MM was sequenced using polymerase chain reaction analysis. Results: In MM, only 2 cases (2.8%) were KIT positive. The great majority of the cases (97, 2%) did not express the KIT receptor tyrosine kinase. No mutation of the c-kit gene was detected. Conclusions: KIT expression is a rare event in MM and not detectable in MGUS and LPL. Therefore, treatment with imatinib is unlikely to be effective in these patient

    Indolent lymphoma: the pathologist's viewpoint

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    Indolent lymphomas have recently been the object of numerous studies, which have focused on new aspects relevant both for the better comprehension of their histogenesis and the identification of new therapeutic strategies. As marginal-zone lymphoma (MZL) represents the category of indolent lymphomas that has obtained more benefit from such an approach, the authors focused on the most recent achievements and not yet solved controversies in this area. In spite of their postulated common derivation, the three categories of MZL of the WHO Classification appear dissimilar. In fact, they show significant molecular differences among them as well as a certain heterogeneity within each group. By no means, there is a cogent need of more refined tools to revise these neoplasms and to produce a more rational grouping. The recent identification of the IRTA gene family corresponding to IG-like receptors differentially expressed in B-cells might contribute to their better understandin

    Comparison of recoil effects in graphite as observed by photoemission, electron scattering, and neutron scattering

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    Recoil effects have been observed for neutron and electron scatterings, and in photoemission. In all cases highly oriented pyrolytic graphite was used as a testing material and dependencies of recoil effects on the crystal orientation were found but these results have, so far, not been compared. We show that the same theory can describe the results of all three experiments in a quantitative way

    Resonant Transmission of Microwaves through a Narrow Metallic Slit

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    Fuzi Yang, and J. Roy Sambles, Physical Review Letters, Vol. 89, article 063901 (2002). "Copyright © 2002 by the American Physical Society."Strong resonant transmission of microwave radiation through a very narrow (much less than the radiation wavelength) metallic slit is recorded. The results show that a set of resonant self-coupled surface plasmons are excited within the small gap, giving a Fabry-Pérot-like behavior in accord with analytical results published earlier [Y. Takakura, Phys. Rev. Lett. 86, 5601 (2001)]. The metallic slit, formed by two thick metal plates spaced apart by tens of microns, is inserted in a wavelength-sized aperture. On resonance the transmissivity through the metal slit is more than 2 orders of magnitude greater than the radiation impinging on the slit area
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