434 research outputs found

    Gauge invariance of color confinement due to the dual Meissner effect caused by Abelian monopoles

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    The mechanism of non-Abelian color confinement is studied in SU(2) lattice gauge theory in terms of the Abelian fields and monopoles extracted from non-Abelian link variables without adopting gauge fixing. Firstly, the static quark-antiquark potential and force are computed with the Abelian and monopole Polyakov loop correlators, and the resulting string tensions are found to be identical to the non-Abelian string tension. These potentials also show the scaling behavior with respect to the change of lattice spacing. Secondly, the profile of the color-electric field between a quark and an antiquark is investigated with the Abelian and monopole Wilson loops. The color-electric field is squeezed into a flux tube due to monopole supercurrent with the same Abelian color direction. The parameters corresponding to the penetration and coherence lengths show the scaling behavior, and the ratio of these lengths, i.e, the Ginzburg-Landau parameter, indicates that the vacuum type is near the border of the type1 and type2 (dual) superconductor. These results are summarized that the Abelian fundamental charge defined in an arbitrary color direction is confined inside a hadronic state by the dual Meissner effect. As the color-neutral state in any Abelian color direction corresponds to the physical color-singlet state, this effect explains non-Abelian color confinement and supports the existence of a gauge-invariant mechanism of color confinement due to the dual Meissner effect caused by Abelian monopoles.Comment: 11 pages, 14 figure

    Abelian dominance and the dual Meissner effect in local unitary gauges in SU(2) gluodynamics

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    Performing highly precise Monte-Carlo simulations of SU(2) gluodynamics, we observe for the first time Abelian dominance in the confining part of the static potential in local unitary gauges such as the F12 gauge. We also study the flux-tube profile between the quark and antiquark in these local unitary gauges and find a clear signal of the dual Meissner effect. The Abelian electric field is found to be squeezed into a flux tube by the monopole supercurrent. This feature is the same as that observed in the non-local maximally Abelian gauge. These results suggest that the Abelian confinement scenario is gauge independent. Observing the important role of space-like monopoles in the Polyakov gauge also indicates that the monopoles defined on the lattice do not necessarily correspond to those proposed by 't Hooft in the context of Abelian projection.Comment: 4 pages, 7 figure

    Testicular somatic cell-like cells derived from embryonic stem cells induce differentiation of epiblasts into germ cells

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    Regeneration of the testis from pluripotent stem cells is a real challenge, reflecting the complexity of the interaction of germ cells and somatic cells. Here we report the generation of testicular somatic cell-like cells (TesLCs) including Sertoli cell-like cells (SCLCs) from mouse embryonic stem cells (ESCs) in xeno-free culture. We find that Nr5a1/SF1 is critical for interaction between SCLCs and PGCLCs. Intriguingly, co-culture of TesLCs with epiblast-like cells (EpiLCs), rather than PGCLCs, results in self-organised aggregates, or testicular organoids. In the organoid, EpiLCs differentiate into PGCLCs or gonocyte-like cells that are enclosed within a seminiferous tubule-like structure composed of SCLCs. Furthermore, conditioned medium prepared from TesLCs has a robust inducible activity to differentiate EpiLCs into PGCLCs. Our results demonstrate conditions for in vitro reconstitution of a testicular environment from ESCs and provide further insights into the generation of sperm entirely in xeno-free culture

    Aldose reductase gene is associated with diabetic macroangiopathy in Japanese Type 2 diabetic patients

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    AIMS: The aldose reductase (AR) gene, a rate-limiting enzyme of the polyol pathway, has been investigated as a candidate gene in determining susceptibility to diabetic microangiopathy. However, the association of the AR gene with diabetic macroangiopathy has not been investigated. Therefore, the present study was conducted to determine whether genetic variations of AR may determine susceptibility to diabetic macroangiopathy. METHODS: There were 378 Type 2 diabetic patients enrolled in this study. A single nucleotide polymorphism in the promoter region (C-106T) was genotyped and the AR protein content of erythrocytes measured by ELISA. RESULTS: There were no significant differences in genotypic or allelic distribution in patients with or without ischaemic heart diseases, but there was a significant increase in the frequency of the CT + TT genotype and T allele in patients with stroke (P = 0.019 and P = 0.012). The erythrocyte AR protein content was increased in patients with the CT and TT genotype compared with those with the CC genotype. After adjustment for age, duration of diabetes, body mass index, systolic blood pressure, HbA(1c), and serum creatinine, triglycerides, and total cholesterol in multivariate logistic-regression models, the association between this AR genotype and stroke remained significant. CONCLUSIONS: Our results suggest that the CT or TT genotype of the AR gene might be a genetic marker of susceptibility to stroke in Type 2 diabetic patients. This observation might contribute to the development of strategies for the prevention of stroke in Type 2 diabetic patients

    Global e-VLBI observations of the gamma-ray narrow line Seyfert 1 PMN J0948+0022

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    There is growing evidence of relativistic jets in radio-loud narrow-line Seyfert 1 (RL-NLS1) galaxies. We constrain the observational properties of the radio emission in the first RL-NLS1 galaxy ever detected in gamma-rays, PMN J0948+0022, i.e., its flux density and structure in total intensity and in polarization, its compactness, and variability. We performed three real-time e-VLBI observations of PMN J0948+0022 at 22 GHz, using a global array including telescopes in Europe, East Asia, and Australia. These are the first e-VLBI science observations ever carried out with a global array, reaching a maximum baseline length of 12458 km. The observations were part of a large multiwavelength campaign in 2009. The source is detected at all three epochs. The structure is dominated by a bright component, more compact than 55 microarcsec, with a fainter component at a position angle theta~ 35deg. Relativistic beaming is required by the observed brightness temperature of 3.4x10^11 K. Polarization is detected at a level of about 1%. The parameters derived by the VLBI observations, in addition to the broad-band properties, confirm that PMN J0948+0022 is similar to flat spectrum radio quasars. Global e-VLBI is a reliable and promising technique for future studies.Comment: Accepted for publication as a Letter in Astronomy and Astrophysic

    PRELP secreted from mural cells protects the function of blood brain barrier through regulation of endothelial cell-cell integrity

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    INTRODUCTION: Proline/arginine-rich end leucine-rich repeat protein (PRELP), is a small secreted proteoglycan expressed by pericytes and vascular smooth muscle cells surrounding the brain vasculature of adult mouse. METHODS: We utilised a Prelp knockout (Prelp−/−) mouse model to interrogate vasculature integrity in the brain alongside performing in vitro assays to characterise PRELP application to endothelial cells lines. Our findings were supplemented with RNA expression profiling to elucidate the mechanism of how PRELP maintains neurovasculature function. RESULTS: Prelp−/− mice presented with neuroinflammation and reducedneurovasculature integrity, resulting in IgG and dextran leakage in the cerebellum and cortex. Histological analysis of Prelp−/− mice revealed reducedcell-cell integrity of the blood brain barrier, capillary attachment of pericytes andastrocyte end-feet. RNA-sequencing analysis found that cell-cell adhesion andinflammation are affected in Prelp−/− mice and gene ontology analysis as well as gene set enrichment analysis demonstrated that inflammation related processes and adhesion related processes such as epithelial-mesenchymal transition and apical junctions were significantly affected, suggesting PRELP is a regulator of cell-cell adhesion. Immunofluorescence analysis showed that adhesion junction protein expression levels of cadherin, claudin-5, and ZO-1, was suppressed in Prelp−/− mice neurovasculature. Additionally, in vitro studies revealed that PRELP application to endothelial cells enhances cell-cell integrity, induces mesenchymal-endothelial transition and inhibits TGF-ÎČ mediated damage to cell-cell adhesion. DISCUSSION: Our study indicates that PRELP is a novel endogenous secreted regulator of neurovasculature integrity and that PRELP application may be a potential treatment for diseases associated with neurovascular damage

    The first scientific experiment using Global e-VLBI observations: a multiwavelength campaign on the gamma-ray Narrow-Line Seyfert 1 PMN J0948+0022

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    The detection of gamma-ray emission by Fermi-LAT from the radio loud Narrow Line Seyfert 1 PMN J0948+0022 (Abdo et al. 2009, ApJ 699, 976) triggered a multi-wavelength campaign between March and July 2009. Given its high compactness (Doi et al. 2006, PASJ 58, 829), inverted spectrum, and 0deg declination, the source was an ideal target to observe at 22 GHz with a Global VLBI array extending from Europe to East Asia and Australia. In order to deliver prompt results to be analysed in combination with the other instruments participating in the campaign, the observations were carried out with real time VLBI, for the first time on a Global scale. Indeed, the main results have been published just a few months after the campaign (Abdo et al. 2009, ApJ 707, 727). Here we present additional details about the e-VLBI observations.Comment: PoS(10th EVN Symposium)080: Proceedings of the 10th European VLBI Network Symposium and EVN Users Meeting: VLBI and the new generation of radio arrays, September 20-24, 2010, Manchester U

    Lysophospahatidic acid stimulates the proliferation and motility of malignant pleural mesothelioma cells through lysophosphatidic acid receptors, LPA1 and LPA2

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    Division of Medical Oncology and Surgical Oncolog
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