479 research outputs found

    Haematopoietic ESL-1 enables stem cell proliferation in the bone marrow by limiting TGF beta availability

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    The life-long maintenance of haematopoietic stem and progenitor cells (HSPCs) critically relies on environmental signals produced by cells that constitute the haematopoietic niche. Here we report a cell-intrinsic mechanism whereby haematopoietic cells limit proliferation within the bone marrow, and show that this pathway is repressed by E-selectin ligand 1 (ESL-1). Mice deficient in ESL-1 display aberrant HSPC quiescence, expansion of the immature pool and reduction in niche size. Remarkably, the traits were transplantable and dominant when mutant and wild-type precursors coexisted in the same environment, but were independent of E-selectin, the vascular receptor for ESL-1. Instead, quiescence is generated by unrestrained production of the cytokine TGF beta by mutant HSPC, and in vivo or in vitro blockade of the cytokine completely restores the homeostatic properties of the haematopoietic niche. These findings reveal that haematopoietic cells, including the more primitive compartment, can actively shape their own environment

    Out-of-core macromolecular simulations on multithreaded architectures

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    We address the solution of large-scale eigenvalue problems that appear in the motion simulation of complex macromolecules on multithreaded platforms, consisting of multicore processors and possibly a graphics processor (GPU). In particular, we compare specialized implementations of several high- performance eigensolvers that, by relying on disk storage and out-of-core (OOC) techniques, can in principle tackle the large memory requirements of these biological problems, which in general do not fit into the main memory of current desktop machines. All these OOC eigensolvers, except for one, are composed of compute-bound (i.e., arithmetically-intensive) operations, which we accelerate by exploiting the performance of current multicore processors and, in some cases, by additionally off-loading certain parts of the computation to a GPU accelerator. One of the eigensolvers is a memory-bound algorithm, which strongly constrains its performance when the data is on disk. However, this method exhibits a much lower arithmetic cost compared with its compute- bound alternatives for this particular application. Experimental results on a desktop platform, representative of current server technology, illustrate the potential of these methods to address the simulation of biological activity

    Accelerating multi-channel filtering of audio signal on ARM processors

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    The researchers from Universitat Jaume I are supported by the CICYT projects TIN2014-53495-R and TIN2011-23283 of the Ministerio de Economía y Competitividad and FEDER. The authors from the Universitat Politècnica de València are supported by projects TEC2015-67387-C4-1-R and PROMETEOII/2014/003. This work was also supported from the European Union FEDER (CAPAP-H5 network TIN2014-53522-REDT)

    Mini AuAg Wavy Nanorods Displaying Plasmon-Induced Photothermal and Photocatalytic Properties

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    Alloyed AuAg wavy nanorods (wNRs) of approximate to 24.0 nm length and 3.5 nm width are formed by the mild decomposition of the organometallic complex [Au2Ag2(C6F5)(4)(OEt2)(2)](n) in tetrahydrofuran (THF) in the presence of oleic acid. Ligand exchange with l-glutathione (GSH) or poly(ethylene glycol) methyl ether thiol (PEG-SH) leads to water-soluble nanostructures. These AuAg wNRs display tunable size-dependent longitudinal localized surface plasmon resonance (l-LSPR) broad absorptions beyond 750 nm in the near-infrared (NIR) I and II regions. These intense plasmonic absorptions lead to interesting photothermal, catalytic, and photocatalytic properties, including the catalytic reduction of 4-nitrophenol, the photocatalytic reduction of 4-nitrostyrene, or the photocatalytic dehydrogenation of ammonia borane for H-2 release

    The Impact of the Multi-core Revolution on Signal Processing

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    This paper analyzes the influence of new multi- core and many-core architectures on Signal Processing. The article covers both the architectural design and the programming models of current general-purpose multi-core processors and graphics processors (GPU), with the goal of identifying their possibilities and impact on signal processing applications

    Simultaneous Determination of Refractive Index and Thickness of Submicron Optical Polymer Films from Transmission Spectra

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    High-transparency polymers, called optical polymers (OPs), are used in many thin-film devices, for which the knowledge of film thickness (h) and refractive index (n) is generally required. Spectrophotometry is a cost-effective, simple and fast non-destructive method often used to determine these parameters simultaneously, but its application is limited to films where h > 500 nm. Here, a simple spectrophotometric method is reported to obtain simultaneously the n and h of a sub-micron OP film (down to values of a few tenths of a nm) from its transmission spectrum. The method is valid for any OP where the n dispersion curve follows a two-coefficient Cauchy function and complies with a certain equation involving n at two different wavelengths. Remarkably, such an equation is determined through the analysis of n data for a wide set of commercial OPs, and its general validity is demonstrated. Films of various OPs (pristine or doped with fluorescent compounds), typically used in applications such as thin-film organic lasers, are prepared, and n and h are simultaneously determined with the proposed procedure. The success of the method is confirmed with variable-angle spectroscopic ellipsometry.Spanish Ministry of Economy and Competitivity (MINECO) and European Community (FEDER) through grant no. MAT2015-66586-R

    Outcome of Enterococcus faecalis infective endocardits according to the length of antibiotic therapy: Prelininary data from a cohort of 78 patients.

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    Background International guidelines recommend 4 weeks of treatment with ampicillin plus gentamicin (A+G) for uncomplicated native valve Enterococcus faecalis infective endocarditis (EFIE) and 6 weeks in the remaining cases. Ampicillin plus ceftriaxone (A+C) is always recommended for at least 6w, with no available studies assessing its suitability for 4w. We aimed to investigate differences in the outcome of EFIE according to the duration (4 versus 6 weeks) of antibiotic treatment (A+G or A+C). Methods Retrospective analysis from a prospectively collected cohort of 78 EFIE patients treated with either A+G or A+C. Results 32 cases (41%) were treated with A+G (9 for 4w, 28%) and 46 (59%) with A+C (14 for 4w, 30%). No significant differences were found in 1-year mortality according to the type of treatment (31% and 24% in A+G and A+C, respectively; P = 0.646) or duration (26% and 27% at 4 and 6w, respectively; P = 0.863). Relapses were more frequent among survivors treated for 4w than in those treated for 6w (3/18 [17%] at 4w and 1/41 [2%] at 6w; P = 0.045). Three out of 4 (75%) relapses occurred in cirrhotic patients. Conclusions A 4-week course of antibiotic treatment might not be suitable neither for A+G nor A+C for treating uncomplicated native valve EFIE

    Application of Multi-core and GPU Architectures on Signal Processing: Case Studies

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    In this article part of the techniques and developments we are carrying out within the INCO2 group are reported. Results follow the interdisciplinary approach with which we tackle signal processing applications. Chosen case studies show different stages of development: We present algorithms already completed which are being used in practical applications as well as new ideas that may represent a starting point, and which are expected to deliver good results in a short and medium term

    Galaxy clusters and groups in the ALHAMBRA Survey

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    We present a catalogue of 348 galaxy clusters and groups with 0.2<z<1.20.2<z<1.2 selected in the 2.78 deg2deg^2 ALHAMBRA Survey. The high precision of our photometric redshifts, close to 1%1\%, and the wide spread of the seven ALHAMBRA pointings ensure that this catalogue has better mass sensitivity and is less affected by cosmic variance than comparable samples. The detection has been carried out with the Bayesian Cluster Finder (BCF), whose performance has been checked in ALHAMBRA-like light-cone mock catalogues. Great care has been taken to ensure that the observable properties of the mocks photometry accurately correspond to those of real catalogues. From our simulations, we expect to detect galaxy clusters and groups with both 70%70\% completeness and purity down to dark matter halo masses of Mh∼3×1013M⊙M_h\sim3\times10^{13}\rm M_{\odot} for z<0.85z<0.85. Cluster redshifts are expected to be recovered with ∼0.6%\sim0.6\% precision for z<1z<1. We also expect to measure cluster masses with σMh∣MCL∗∼0.25−0.35 dex\sigma_{M_h|M^*_{CL}}\sim0.25-0.35\, dex precision down to ∼3×1013M⊙\sim3\times10^{13}\rm M_{\odot}, masses which are 50%50\% smaller than those reached by similar work. We have compared these detections with previous optical, spectroscopic and X-rays work, finding an excellent agreement with the rates reported from the simulations. We have also explored the overall properties of these detections such as the presence of a colour-magnitude relation, the evolution of the photometric blue fraction and the clustering of these sources in the different ALHAMBRA fields. Despite the small numbers, we observe tentative evidence that, for a fixed stellar mass, the environment is playing a crucial role at lower redshifts (z<<0.5).Comment: Accepted for publication in MNRAS. Catalogues and figures available online and under the following link: http://bascaso.net46.net/ALHAMBRA_clusters.htm
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