6,799 research outputs found

    Measurement of collective flow in heavy ion collisions using particle pair correlations

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    We present a new type of flow analysis, based on a particle-pair correlation function, in which there is no need for an event-by-event determination of the reaction plane. Consequently, the need to correct for dispersion in an estimated reaction plane does not arise. Our method also offers the option to avoid any influence from particle misidentification. Using this method, streamer chamber data for collisions of Ar+KCl and Ar+BaI2 at 1.2 GeV/nucleon are compared with predictions of a nuclear transport model

    Dynamics of Neural Networks with Continuous Attractors

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    We investigate the dynamics of continuous attractor neural networks (CANNs). Due to the translational invariance of their neuronal interactions, CANNs can hold a continuous family of stationary states. We systematically explore how their neutral stability facilitates the tracking performance of a CANN, which is believed to have wide applications in brain functions. We develop a perturbative approach that utilizes the dominant movement of the network stationary states in the state space. We quantify the distortions of the bump shape during tracking, and study their effects on the tracking performance. Results are obtained on the maximum speed for a moving stimulus to be trackable, and the reaction time to catch up an abrupt change in stimulus.Comment: 6 pages, 7 figures with 4 caption

    In vitro propagation and homing of liver-derived dendritic cell progenitors to lymphoid tissues of allogeneic recipients: Implications for the establishment and maintenance of donor cell chimerism following liver transplantation

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    Dendritic cell (DC) progenitors were propagated in liquid culture from nonparenchymal cells resident in normal mouse (B10.BR; H-2k, I-E+) liver in response to granulocyte-macrophage colony stimulating factor (GM-CSF). The liver-derived DC progenitors were MHC class II-/dim and did not express counter receptors for CTLA-4, a structural homologue of the Т cell activation molecule CD28. Following subcutaneous or intravenous injection, these liver-derived cells migrated to Т cell-dependent areas of lymph nodes and spleen of unmodified, allogeneic (BIO; H-2b; I-E_) recipients, where they were identified 1-5 days, and 1 and 2 months after injection by their strong surface expression of donor MHC class II (I-Ek) and their dendritic morphology. Maximal numbers of liver-derived DC in the spleen were recorded 5 days after injection. Both clusters of strongly donor MHC class II+ cells— and (more rarely) dividing cells—could also be identified, suggesting cell replication in situ. Using the same techniques employed to generate DC progenitors from normal liver, GM-CSF-stimulated cells were propagated for 10 days from the bone marrow and spleen of nonimmunosuppressed mice sacrificed 14 days after orthotopic liver transplantation (B10;H-2b → C3H;H-2k). Immunocytochemical staining for recipient and donor MHC class II phenotype revealed the growth both of host cells with DC characteristics, and of cells expressing donor alloantigens (I-Ab). These results are consistent with the growth, in response to GM-CSF, of donor-derived DC from progenitors seeded from the liver allograft to recipient lymphoid tissue. The functional activity of the progenitors of chimeric DC and the possible role of these cells in the establishment and maintenance of donor-specific tolerance following liver transplantation remain to be determined. © 1995 by Williams and Wilkins

    Coherent magnetic plasmon modes in a contacting gold nano-sphere chain on a gold Slab

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    A coupled magnetic resonator waveguide, composed of a contacting gold nanosphere chain on a gold slab, is proposed and investigated. A broadband coherent magnetic plasmon mode can be excited in this one dimensional nanostructure. By employing the Lagrangian formalism and the Fourier transform method, the dispersion properties of the wave vector and group velocity of the magnetic plasmon mode are investigated. Small group velocity can be obtained from this system which can be applied as subwavelength slow wave waveguides.Comment: 11pages, 5 figures, This work is published at Optics Express 19, 23782 (2011

    Measurement of teicoplanin by liquid chromatography-tandem mass spectrometry:development of a novel method

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    Teicoplanin is an antibiotic used for the treatment of endocarditis, osteomyelitis, septic arthritis and methicillin-resistant Staphylococcus aureus. Teicoplanin is emerging as a suitable alternative antibiotic to vancomycin, where their trough serum levels are monitored by immunoassay routinely. This is the first report detailing the development of a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for measuring teicoplanin in patients' serum

    Barrier height change in very thin SiO2 films caused by charge injection

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    In this paper, we report an investigation of barrier height change in gate oxide caused by charge injection. By analyzing the small change in the post-stress Fowler-Nordheim (FN) tunneling current through the oxide layer, the change of the oxide barrier height due to charge injection is determined quantitatively. The barrier height changes associated with different charge-injection directions and measurement polarities for n-channel metal oxide semiconductor field-effect transistors (MOSFETs) are presented. For comparison a measurement on a p-channel MOSFET is also carried out. For all the cases, the barrier height changes always exhibit a power law dependence on injected charge.published_or_final_versio

    Pharmacogenetics of Bisphosphonate-associated Osteonecrosis of the Jaw

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    Osteonecrosis of the jaws (ONJ) is a potentially severe disorder that develops in a subgroup of individuals who have used bisphosphonate (BP) medications. Several clinical risk factors have been associated with the risk of ONJ development, but evidence is limited and in most instances ONJ remains an unpredictable adverse drug reaction. Interindividual genetic variability can contribute to explaining ONJ development in a subset of BP users and the discovery of relevant associated gene variants could lead to the identification of individuals at higher risk. No genetic variant has been found to be robustly associated with susceptibility to ONJ

    Pancreatic islet transplantation after upper abdominal exeriteration and liver replacement

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    Nine patients who became diabetic after upper-abdominal exenteration and liver transplantation were given pancreatic islet-cell grafts obtained from the liver donor (eight cases), a third-party donor (one), or both (four). Two patients were diabetic when they died of infections after 48 and 109 days, as was a third patient who died of tumour recurrence after 178 days. The other 6 are alive 101-186 days postoperatively, and five are insulin-free or on insulin only during night-time parenteral alimentation. C-peptide increased 1·7 to 3·3 fold in response to intravenous glucose in these five patients who have had glycosylated haemoglobin in the high normal range. However, the kinetics of the C-peptide responses to intravenous glucose in all eight patients tested revealed an absent first-phase release and a delayed peak response consistent with transplantation and/or engraftment of a suboptimal islet cell mass. The longest survivor, who requires neither parenteral alimentation nor insulin, is the first unequivocal example of successful clinical islet-cell transplantation. © 1990
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