4,861 research outputs found
Immunoglobulin VH Chain Gene Analysis of Peripheral Blood IgM-Producing B Cells in Patients with Kawasaki Disease
PURPOSE: Kawasaki disease is a systemic vasculitis, and its etiology and pathogenesis are still not clear. Our study was undertaken to investigate the characteristics of the activation of B cells in the peripheral blood of Kawasaki disease (KD) patients and evidence of stimulation by superantigens.
MATERIALS AND METHODS: Blood samples were obtained from three patients (2 males, 1 female) with KD, who were admitted to our Hospital, Seoul, Korea. The mean age was 1.2 years. Distribution of B cells was studied in the acute and subacute phases of KD patients. From the RNA of B cells, we obtained complementary DNA (cDNA) and performed polymerase chain reaction (PCR). To determine the oligoclonal expansion of immunoglobulin M (IgM) V(H) family, we cloned and sequenced the PCR products from each group and analyzed DNA.
RESULTS: In the peripheral blood of acute phase patients, T cells were significantly decreased (p < 0.05), whereas B cells were significantly increased (p < 0.05). When the first PCR was done on the B cell chains, V(H)1 to V(H)6 were all found to be expressed. The number of micro gene clones obtained from 3 patients was 312, and they belonged to V(H)3, V(H)4 and V(H)5 family. M99686 germ line was most frequently used and the next most frequently used, were X92224/J, L21967 and L21964. A similar order was seen in patients. Among the clones, 20 sets of clones showed the same base sequence and this was frequent between V(H)2 and V(H)5. There was one set, which showed almost the same base sequence between different patients, and the homology was 99.5%. Twenty sets of clones that had the same base sequence showed high similarity to the germ line (94 - 100%). Among these, the clones that utilized the M99686 germ line were 4 sets which were most frequent. The 3-dimensional structure of one of these clones showed typical beta, sheet structure of immunoglobulin chains.
CONCLUSION: The IgM transcripts expressed by the B cells in the peripheral blood of KD patients in the acute phase of the disease clearly showed an oligoclonal expansion, suggesting that KD is caused not by stimulation of a superantigen, but rather by a conventional antigen.ope
Helveticoside is a biologically active component of the seed extract of Descurainia sophia and induces reciprocal gene regulation in A549 human lung cancer cells
Critical currents for vortex defect motion in superconducting arrays
We study numerically the motion of vortices in two-dimensional arrays of
resistively shunted Josephson junctions. An extra vortex is created in the
ground states by introducing novel boundary conditions and made mobile by
applying external currents. We then measure critical currents and the
corresponding pinning energy barriers to vortex motion, which in the
unfrustrated case agree well with previous theoretical and experimental
findings. In the fully frustrated case our results also give good agreement
with experimental ones, in sharp contrast with the existing theoretical
prediction. A physical explanation is provided in relation with the vortex
motion observed in simulations.Comment: To appear in Physical Review
Optimal frequency regulation of multi-terminal HVDC-linked grids with deloaded offshore wind farms control
© 2023 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.This paper proposes a new decentralized strategy for optimal grid frequency regulation (GFR) in an interconnected power system, where onshore grids and offshore wind farms (OWFs) are linked using a multi-terminal high-voltage direct-current (MTDC) system. In the proposed strategy, grid- and OWF-side optimal controllers are developed to coordinate the operations of synchronous generators and the MTDC converter, and the OWF and the MTDC converter, respectively, thus achieving optimal generator power and deloaded OWF power sharing of the interconnected grids and minimizing frequency deviations in each grid. Full-order dynamic models of an MTDC-linked grid and an OWF are implemented, and given each dynamic model, grid- and OWF-side decentralized linear quadratic Gaussian regulators are designed for optimal GFR of the MTDC-linked grids and supporting GFR through optimal deloading operation of the OWFs, respectively. Eigenvalue analyses are conducted with a focus on the effects of system parameter uncertainties and communication time delays. Comparative case studies are also performed to verify that the proposed strategy improves the effectiveness and stability of real-time GFR in MTDC-linked grids under various conditions.Postprint (author's final draft
Spatiotemporal Stochastic Resonance in Fully Frustrated Josephson Ladders
We consider a Josephson-junction ladder in an external magnetic field with
half flux quantum per plaquette. When driven by external currents, periodic in
time and staggered in space, such a fully frustrated system is found to display
spatiotemporal stochastic resonance under the influence of thermal noise. Such
resonance behavior is investigated both numerically and analytically, which
reveals significant effects of anisotropy and yields rich physics.Comment: 8 pages in two columns, 8 figures, to appear in Phys. Rev.
State Estimation Filtering using Recent Finite Measurements and Inputs for Active Suspension System with Temporary Uncertainties
In this paper, the finite memory structure(FMS) filter using most recent finite measured outputs and control inputs is applied for the state estimation filtering of automotive suspension systems to verify intrinsic robustness of FMS filter. Firstly, the single-corner model for the automotive suspension system and its state-space model are described. Secondly, FMS as well as infinite memory structure(IMS) filters are briefly introduced and represented by the summation form. Thirdly, a couple of temporary uncertainties, model uncertainty and unknown input, are discussed. Finally, extensive computer simulations are performed for both nominal system and temporarily uncertain system. It is shown that the FMS filter can be better than the IMS filter for both temporary uncertainties. In addition, the FMS filter can be shown to be comparable to the IMS filter after the effects of a couple of temporary uncertainties have completely disappeared
Assessment of the Impacts of Global Climate Change and Regional Water Projects on Streamflow Characteristics in the Geum River Basin in Korea
The impacts of two factors on future regional-scale runoff were assessed: the external factor of climate change and the internal factor of a recently completed large-scale water resources project. A rainfall-runoff model was built (using the Soil and Water Assessment Tool, SWAT) for the Geum River, where three weirs were recently constructed along the main stream. RCP (Representative Concentration Pathways) climate change scenarios from the HadGEM3-RA RCM model were used to generate future climate scenarios, and daily runoff series were constructed based on the SWAT model. The indicators of the hydrologic alteration (IHA) program was used to carry out a quantitative assessment on the variability of runoff during two future periods (2011–2050, 2051–2100) compared to a reference period (1981–2006). Analyses of changes in the runoff characteristics of the lower Geum River showed that climate change is likely to lead to an increase of the future runoff ratio and that weirs contributed to an increase in the minimum discharge and a decrease in the maximum discharge. The influence of the weirs on the runoff characteristics of the Geum River basin was projected to be greater than that of climate change
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