299 research outputs found

    Inter-meson Potentials in Dual Ginzburg-Landau Theory

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    We calculate inter-meson potentials numerically by solving classical equations of motion derived from Dual Ginzburg-Landau (DGL) Theory. Inter-meson potentials in DGL theory are shown to be similar to those of the string-flip model and well reproduce behaviors of the short-range interaction at the classical level. We also compare our results with those from lattice QCD Monte carlo calculations.Comment: 18 pages, latex, 8 figure

    Modeling of single pole write head and double-layered medium for 3-D eddy current analysis

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    Finite-element modeling of single pole (SPT) write head with double-layered medium for perpendicular magnetic recording is investigated. In carrying out 3-D eddy current transient finite-element analysis, reducing the medium area is one key factor for computation time reduction while maintaining sufficient solution accuracy. It is also investigated the number of layer divisions for thin metallic under-layer. The results validate the modeling of SPT head with double-layerd medium

    Redshift-space Distortions of the Power Spectrum of Cosmological Objects on a Light Cone : Explicit Formulations and Theoretical Implications

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    We examine the effects of the linear and the cosmological redshift-space distortions on the power spectrum of cosmological objects on a light cone. We develop theoretical formulae for the power spectrum in linear theory of density perturbations in a rigorous manner starting from first principle corresponding to Fourier analysis. Approximate formulae, which are useful properly to incorporate the redshift-space distortion effects into the power spectrum are derived, and the validity is examined. Applying our formulae to galaxy and quasar samples which roughly match the SDSS survey, we will show how the redshift-space distortions distort the power spectrum on the light cone quantitatively.Comment: 30 pages, Accepted for publication in the Astrophysical Journal Supplement Serie

    Intra-articular osteoid osteoma of the calcaneus: a case report and review

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    AbstractOsteoid osteoma of the calcaneus is rare and frequently misdiagnosed as arthritis because of similar symptoms. In addition, radiographic findings may be nonspecific, and magnetic resonance imaging (MRI) may show a bone marrow edema and changes in adjacent soft tissue. A 19-year-old man presented with a 6-month history of persistent pain and swelling in the left hind foot; diagnostic computed tomography and MRI analyses revealed lesions suggesting an intra-articular osteoid osteoma of the calcaneus. Initial MRI did not show specific findings. On operation, the tumor was removed by curettage; pathologic findings demonstrated woven bone trabeculae surrounded by connective tissue, confirming the diagnosis. To the best of our knowledge, MRI scans in all cases of calcaneal osteoid osteoma reported till 3 months after the injury exhibited a nidus. We believe that calcaneal osteoid osteoma should be considered as a differential diagnosis in patients undergoing MRI 3 months after symptom presentation; early computed tomography is critical in diagnosis

    Compensatory Thrombopoietin Production from the Liver and Bone Marrow Stimulates Thrombopoiesis of Living Rat Megakaryocytes in Chronic Renal Failure

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    Background/Aims: Decreased thrombopoiesis has been ascribed a role in the pathogenesis of uremic bleeding in chronic renal failure (CRF). However, serum thrombopoietin (TPO) levels are usually elevated in CRF patients, suggesting increased thrombopoiesis. The aim of this study was to determine the thrombopoietic activity in CRF. Methods: Male Sprague-Dawley rats that underwent 5/6 nephrectomy were used as the model of CRF. Age-matched sham-operated rats were used as controls. Single megakaryocytes were isolated from the rat bone marrow, and their size distribution was examined. Megakaryocyte membrane invaginations were monitored by confocal imaging of di-8-ANEPPS staining, and patch clamp whole-cell recordings of membrane capacitance. TPO gene expression was assessed in various tissues. Results: Circulating platelet counts and the number of large megakaryocytes were increased in the bone marrow of CRF rats. Massive di-8-ANEPPS staining and increased membrane capacitance in large megakaryocytes demonstrated increased membrane invaginations. Unaffected Kv1.3-channel currents per cell surface area demonstrated unaltered channel densities. TPO transcription was decreased in the renal cortex but increased in the liver and bone marrow of CRF rats. Conclusion: Increased thrombopoiesis in CRF was thought to be a reactive mechanism to platelet dysfunction. Increased TPO production from the liver and bone marrow compensated for decreased production from damaged kidneys

    PARM-1 Is an Endoplasmic Reticulum Molecule Involved in Endoplasmic Reticulum Stress-Induced Apoptosis in Rat Cardiac Myocytes

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    To identify novel transmembrane and secretory molecules expressed in cardiac myocytes, signal sequence trap screening was performed in rat neonatal cardiac myocytes. One of the molecules identified was a transmembrane protein, prostatic androgen repressed message-1 (PARM-1). While PARM-1 has been identified as a gene induced in prostate in response to castration, its function is largely unknown. Our expression analysis revealed that PARM-1 was specifically expressed in hearts and skeletal muscles, and in the heart, cardiac myocytes, but not non-myocytes expressed PARM-1. Immunofluorescent staining showed that PARM-1 was predominantly localized in endoplasmic reticulum (ER). In Dahl salt-sensitive rats, high-salt diet resulted in hypertension, cardiac hypertrophy and subsequent heart failure, and significantly stimulated PARM-1 expression in the hearts, with a concomitant increase in ER stress markers such as GRP78 and CHOP. In cultured cardiac myocytes, PARM-1 expression was stimulated by proinflammatory cytokines, but not by hypertrophic stimuli. A marked increase in PARM-1 expression was observed in response to ER stress inducers such as thapsigargin and tunicamycin, which also induced apoptotic cell death. Silencing PARM-1 expression by siRNAs enhanced apoptotic response in cardiac myocytes to ER stresses. PARM-1 silencing also repressed expression of PERK and ATF6, and augmented expression of CHOP without affecting IRE-1 expression and JNK and Caspase-12 activation. Thus, PARM-1 expression is induced by ER stress, which plays a protective role in cardiac myocytes through regulating PERK, ATF6 and CHOP expression. These results suggested that PARM-1 is a novel ER transmembrane molecule involved in cardiac remodeling in hypertensive heart disease
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