8,103 research outputs found

    Theory of current-driven motion of Skyrmions and spirals in helical magnets

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    We study theoretically the dynamics of the spin textures, i.e., Skyrmion crystal (SkX) and spiral structure (SS), in two-dimensional helical magnets under external current. By numerically solving the Landau-Lifshitz-Gilbert equation, it is found that (i) the critical current density of the motion is much lower for SkX compared with SS in agreement with the recent experiment, (ii) there is no intrinsic pinning effect for SkX and the deformation of the internal structure of Skyrmion reduces the pinning effect dramatically, (iii) the Bragg intensity of SkX shows strong time-dependence as can be observed by neutron scattering experiment.Comment: 4 pages, 3 figure

    Suppression of proline-directed protein kinase FAexpression inhibits the growth of human chronic myeloid leukaemia cells

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    Initial studies revealed that proline-directed protein kinase FA(PDPK FA) was overexpressed in various cancerous tissues relative to normal controls. However, the functional role of overexpressed PDPK FAin cancer remains to be established. In this report, we explore the potential role of PDPK FAin leukaemia cell growth by investigating the effects of partial inhibition of this kinase on the malignant phenotype of human chronic myeloid leukaemia cells (K562). Cloning of PDPK FAcDNA and its recombinant antisense expression vector and PDPK FA-specific antibody were successfully developed. Two stable antisense clones of K562 cells were subcloned which expressed 70% and 45% of PDPK FArespectively, compared with control-transfected clone in both immunoprecipitate activity assay and immunoblot analysis. In sharp contrast, these two antisense clones expressed no significant suppression of any other related PDPK family members, indicating the specificity of these two antisense clones. Moreover, these antisense clones proportionally and potentially exhibited cell growth retardation, poor clonogenic growth in soft agar and loss of serum independence. The results demonstrate that specific antisense suppression of PDPK FAis sufficient to interfere with the growth of K562 cells, indicating that PDPK FAis essential for human chronic myeloid leukaemia cell growth. © 2000 Cancer Research Campaig

    Functional properties, structural studies and chemoenzymatic synthesis of oligosaccharides

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    Oligosaccharides offer beneficial effects on immune system and gut health, such as anticancer activity, immunomodulatory activity, and complement activation. Functional oligosaccharides are widely found in plants, algae, bacteria and higher fungi. Milk oligosaccharides, especially human milk oligosaccharides, have considerable health benefits, such as the growth-promotion of the beneficial bacterial flora in the intestines, and developing resistance to bactertial and viral infections. Recent developments in high performance liquid chromatography, mass spectrometry, nuclear magnetic resonance and capillary electrophoresis techniques contribute to the analysis of the oligosaccharide identification and mixture quantification. Synthesis of oligosaccharides is becoming increasingly important to pharmaceutical industries, in which chemo-enzymatic synthesis is considered as an effective method. This article gives a brief summary of structures, accessible sources, physiological and chemical characteristics, and potential health benefits of functional oligosaccharides

    Local delivery of novel MRTF/SRF inhibitors prevents scar tissue formation in a preclinical model of fibrosis

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    The myocardin-related transcription factor/serum response factor (MRTF/SRF) pathway represents a promising therapeutic target to prevent fibrosis. We have tested the effects of new pharmacological inhibitors of MRTF/SRF signalling in a preclinical model of fibrosis. CCG-222740, a novel MRTF/SRF inhibitor, markedly decreased SRF reporter gene activity and showed a greater inhibitory effect on MRTF/SRF target genes than the previously described MRTF-A inhibitor CCG-203971. CCG-222740 was also five times more potent, with an IC50 of 5 ΌM, in a fibroblast-mediated collagen contraction assay, was less cytotoxic, and a more potent inhibitor of alpha-smooth muscle actin protein expression than CCG-203971. Local delivery of CCG-222740 and CCG-203971 in a validated and clinically relevant rabbit model of scar tissue formation after glaucoma filtration surgery increased the long-term success of the surgery by 67% (P < 0.0005) and 33% (P < 0.01), respectively, and significantly decreased fibrosis and scarring histologically. Unlike mitomycin-C, neither CCG-222740 nor CCG-203971 caused any detectable epithelial toxicity or systemic side effects with very low drug levels measured in the aqueous, vitreous, and serum. We conclude that inhibitors of MRTF/SRF-regulated gene transcription such as CCG-222740, potentially represent a new therapeutic strategy to prevent scar tissue formation in the eye and other tissues

    Emission from the D1D5 CFT: Higher Twists

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    We study a certain class of nonextremal D1D5 geometries and their ergoregion emission. Using a detailed CFT computation and the formalism developed in arXiv:0906.2015 [hep-th], we compute the full spectrum and rate of emission from the geometries and find exact agreement with the gravity answer. Previously, only part of the spectrum had been reproduced using a CFT description. We close with a discussion of the context and significance of the calculation.Comment: 39 pages, 6 figures, late

    Characterization of Fine Particulate Matter and Associations between Particulate Chemical Constituents and Mortality in Seoul, Korea

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    Background: Numerous studies have linked fine particles [≀ 2.5 ”m in aerodynamic diameter (PM2.5)] and health. Most studies focused on the total mass of the particles, although the chemical composition of the particles varies substantially. Which chemical components of fine particles that are the most harmful is not well understood, and research on the chemical composition of PM2.5 and the components that are the most harmful is particularly limited in Asia

    Quantum Interference of Photon Pairs from Two Trapped Atomic Ions

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    We collect the fluorescence from two trapped atomic ions, and measure quantum interference between photons emitted from the ions. The interference of two photons is a crucial component of schemes to entangle atomic qubits based on a photonic coupling. The ability to preserve the generated entanglement and to repeat the experiment with the same ions is necessary to implement entangling quantum gates between atomic qubits, and allows the implementation of protocols to efficiently scale to larger numbers of atomic qubits.Comment: 4 pages, 4 figure

    Antiretroviral Therapy in the Malawi Police Force: Access to Therapy and Treatment Outcomes

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    A national survey was carried out in all the 103 public sector and 38 private sector facilities in Malawi providing antiretroviral therapy (ART) to determine uptake of ART and subsequent treatment outcomes in police force personnel. All patients registered for ART and their subsequent treatment outcomes were censored on December 31st 2006. There were 85168 patients started on ART in both public and private sectors, of whom 463 (0.6%) were police force personnel. Of police force personnel starting ART, 17% were in WHO clinical stage 1 or 2 with a CD4-lymphocyte count of &#8804;250 cells/&#956;L and 83% were in stage 3 or 4. Treatment outcomes of police force personnel by the end of December 2006 were 302 (65%) alive and on ART at their registration facility, 59 (13%) dead, 30 (7%) lost to follow-up, 1 stopped treatment and 71 (15%) transferred to another facility. Their probability of being alive on ART at 6-, 12- and 18-months was 83.2%, 78.6% and 76.7% respectively. There has been a good access of police force personnel to ART since national scale up commenced with good treatment outcomes, and this should serve as an example for other police forces in the region. Malawi Medical Journal Vol. 20 (1) 2008 pp. 23-2

    Erythropoietin reduces neuronal cell death and hyperalgesia induced by peripheral inflammatory pain in neonatal rats

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    Painful stimuli during neonatal stage may affect brain development and contribute to abnormal behaviors in adulthood. Very few specific therapies are available for this developmental disorder. A better understanding of the mechanisms and consequences of painful stimuli during the neonatal period is essential for the development of effective therapies. In this study, we examined brain reactions in a neonatal rat model of peripheral inflammatory pain. We focused on the inflammatory insult-induced brain responses and delayed changes in behavior and pain sensation. Postnatal day 3 pups received formalin injections into the paws once a day for 3 days. The insult induced dysregulation of several inflammatory factors in the brain and caused selective neuronal cell death in the cortex, hippocampus and hypothalamus. On postnatal day 21, rats that received the inflammatory nociceptive insult exhibited increased local cerebral blood flow in the somatosensory cortex, hyperalgesia, and decreased exploratory behaviors. Based on these observations, we tested recombinant human erythropoietin (rhEPO) as a potential treatment to prevent the inflammatory pain-induced changes. rhEPO treatment (5,000 U/kg/day, i.p.), coupled to formalin injections, ameliorated neuronal cell death and normalized the inflammatory response. Rats that received formalin plus rhEPO exhibited normal levels of cerebral blood flow, pain sensitivity and exploratory behavior. Treatment with rhEPO also restored normal brain and body weights that were reduced in the formalin group. These data suggest that severe inflammatory pain has adverse effects on brain development and rhEPO may be a possible therapy for the prevention and treatment of this developmental disorder
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