375 research outputs found

    Chondroitin sulfates in the developing rat hindbrain confine commissural projections of vestibular nuclear neurons.

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    BACKGROUND: Establishing correct neuronal circuitry is crucial to proper function of the vertebrate nervous system. The abundance of chondroitin sulfate (CS) proteoglycans in embryonic neural environments suggests that matrix proteoglycans regulate axonal projections when fiber tracts have not yet formed. Among the early-born neurons, the vestibular nucleus (VN) neurons initiate commissural projections soon after generation at E12.5 and reach the contralateral target by E15.5 in the rat hindbrain. We therefore exploited 24-hour cultures (1 day in vitro (DIV)) of the rat embryos and chondroitinase ABC treatment of the hindbrain matrix to reveal the role of CS moieties in axonal initiation and projection in the early hindbrain. RESULTS: DiI tracing from the VN at E12.5(+1 DIV) showed contralaterally projecting fibers assuming fascicles that hardly reached the midline in the controls. In the enzyme-treated embryos, the majority of fibers were unfasciculated as they crossed the midline at 90°. At E13.5(+1 DIV), the commissural projections formed fascicles and crossed the midline in the controls. Enzyme treatment apparently did not affect the pioneer axons that had advanced as thick fascicles normal to the midline and beyond, towards the contralateral VN. Later projections, however, traversed the enzyme-treated matrix as unfasciculated fibers, deviated from the normal course crossing the midline at various angles and extending beyond the contralateral VN. This suggests that CSs also limit the course of the later projections, which otherwise would be attracted to alternative targets. CONCLUSIONS: CS moieties in the early hindbrain therefore control the course and fasciculation of axonal projections and the timing of axonal arrival at the target.RIGHTS : This article is licensed under the BioMed Central licence at http://www.biomedcentral.com/about/license which is similar to the 'Creative Commons Attribution Licence'. In brief you may : copy, distribute, and display the work; make derivative works; or make commercial use of the work - under the following conditions: the original author must be given credit; for any reuse or distribution, it must be made clear to others what the license terms of this work are

    Anomalous tqγtq\gamma coupling effects in exclusive radiative B-meson decays

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    The top-quark FCNC processes will be searched for at the CERN LHC, which are correlated with the B-meson decays. In this paper, we study the effects of top-quark anomalous interactions tqγtq\gamma in the exclusive radiative BKγB\to K^*\gamma and BργB\to\rho\gamma decays. With the current experimental data of the branching ratios, the direct CP and the isospin asymmetries, bounds on the coupling κtcRγ\kappa_{tcR}^{\gamma} from BKγB\to K^*\gamma and κtuRγ\kappa_{tuR}^{\gamma} from BργB\to \rho\gamma decays are derived, respectively. The bound on κtcRγ|\kappa_{tcR}^{\gamma}| from B(BKγ){\mathcal B}(B\to K^{*}\gamma) is generally compatible with that from B(BXsγ){\mathcal B}(B\to X_{s}\gamma). However, the isospin asymmetry Δ(Kγ)\Delta(K^{*}\gamma) further restrict the phase of κtcRγ\kappa_{tcR}^{\gamma}, and the combined bound results in the upper limit, B(tcγ)<0.21\mathcal B(t\to c\gamma)<0.21%, which is lower than the CDF result. For real κtcRγ\kappa_{tcR}^{\gamma}, the upper bound on B(tcγ)\mathcal B(t\to c\gamma) is about of the same order as the 5σ5\sigma discovery potential of ATLAS with an integrated luminosity of 10fb110 {\rm fb}^{-1}. For BργB\to\rho\gamma decays, the NP contribution is enhanced by a large CKM factor Vud/Vtd|V_{ud}/V_{td}|, and the constraint on tuγtu\gamma coupling is rather restrictive, B(tuγ)<1.44×105\mathcal B(t\to u\gamma)<1.44\times 10^{-5}. With refined measurements to be available at the LHCb and the future super-B factories, we can get close correlations between BVγB\to V \gamma and the rare tqγt\to q\gamma decays, which will be studied directly at the LHC ATLAS and CMS.Comment: 25 pages, 15 figures, pdflate

    Resummations with renormalon effects for the hadronic vacuum polarization contribution to the muon (g-2)

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    The hadronic vacuum polarization contribution to the muon (g-2) value is calculated by considering a known dispersion integral which involves the Re+e(s)R_{e+ e-}(s) ratio. The theoretical part stemming from the region below 1.8 GeV is the largest contribution in our approach, and is calculated by using a contour integral involving the associated Adler function D(Q2)D(Q^2). In the resummations, we explicitly take into account the exactly known renormalon singularity of the leading infrared renormalon in the usual and in the modified Borel transform of D(Q2)D(Q^2), and map further away from the origin the other renormalon singularities by employing judiciously chosen conformal transformations. The renormalon effect increases the predicted value of the hadronic vacuum polarization contribution to the muon (g-2), and therefore diminishes the difference between the recently measured and the SM/QCD-predicted value of (g-2). It is also shown that the total QED correction to the hadronic vacuum polarization is very small, about 0.06 percent.Comment: 16 pages, 2 eps-figures, revtex; changes in presentation; different consideration of the (rho -> pi pi gamma) channel in the data part; as a consequence, the results change slightl

    The muon system of the Daya Bay Reactor antineutrino experiment

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    Search for a Light Sterile Neutrino at Daya Bay

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    FLAME, a novel fuzzy clustering method for the analysis of DNA microarray data

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    BACKGROUND: Data clustering analysis has been extensively applied to extract information from gene expression profiles obtained with DNA microarrays. To this aim, existing clustering approaches, mainly developed in computer science, have been adapted to microarray data analysis. However, previous studies revealed that microarray datasets have very diverse structures, some of which may not be correctly captured by current clustering methods. We therefore approached the problem from a new starting point, and developed a clustering algorithm designed to capture dataset-specific structures at the beginning of the process. RESULTS: The clustering algorithm is named Fuzzy clustering by Local Approximation of MEmbership (FLAME). Distinctive elements of FLAME are: (i) definition of the neighborhood of each object (gene or sample) and identification of objects with "archetypal" features named Cluster Supporting Objects, around which to construct the clusters; (ii) assignment to each object of a fuzzy membership vector approximated from the memberships of its neighboring objects, by an iterative converging process in which membership spreads from the Cluster Supporting Objects through their neighbors. Comparative analysis with K-means, hierarchical, fuzzy C-means and fuzzy self-organizing maps (SOM) showed that data partitions generated by FLAME are not superimposable to those of other methods and, although different types of datasets are better partitioned by different algorithms, FLAME displays the best overall performance. FLAME is implemented, together with all the above-mentioned algorithms, in a C++ software with graphical interface for Linux and Windows, capable of handling very large datasets, named Gene Expression Data Analysis Studio (GEDAS), freely available under GNU General Public License. CONCLUSION: The FLAME algorithm has intrinsic advantages, such as the ability to capture non-linear relationships and non-globular clusters, the automated definition of the number of clusters, and the identification of cluster outliers, i.e. genes that are not assigned to any cluster. As a result, clusters are more internally homogeneous and more diverse from each other, and provide better partitioning of biological functions. The clustering algorithm can be easily extended to applications different from gene expression analysis

    Independent measure of the neutrino mixing angle θ13 via neutron capture on hydrogen at Daya Bay

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    Fatal pancytopenia due to albendazole treatment for strongyloidiasis

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    Improved Measurement of Electron Antineutrino Disappearance at Daya Bay

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    Clinical characteristics, laboratory identification, and in vitro antifungal susceptibility of Trichomonascus (Candida) ciferrii isolates associated with granular myringitis

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    Paper Poster Session - Fungal diagnosis: from culture to molecular techniques: no. P1649BACKGROUND: Trichomonascus (Candida) ciferrii is an emerging opportunistic yeast pathogen that has been increasingly recognised in human infections. T. ciferrii has previously been implicated as the cause of tinea pedis, tinea cruris, onchychomycosis, and less commonly, fungaemia. Recently, we diagnosed four unusual cases of T. ciferrii-associated granular myringitis in Chinese patients in Hong Kong and Shenzhen, China. In this study, we report the clinical characteristics, laboratory identification, and in vitro antifungal susceptibility of T. ciferrii isolates associated with granular myringitis …postprin
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