27 research outputs found

    PARA UMA FILOSOFIA DA LINGUAGEM E CRÍTICA DO CONHECIMENTO

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    Tradução de Para uma filosofia da linguagem e crítica do conhecimento de Walter Benjami

    Amino acid metabolic routes in Trypanosoma cruzi: Possible therapeutic targets against Chagas' disease

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    Chagas' disease is a zoonosis caused by the parasite Trypanosoma cruzi, a haematic protozoan, transmitted by insects from the Reduviidae family. This constitutes a relevant health and socio-economic problem in the Americas, with 11 - 18 million people infected, and approximately 100 million people at risk. The therapeutic possibilities rely into two drugs, nifurtimox® and benznidazole®, that were discovered more than thirty years ago, and are mainly successful during the acute phase of the disease. In the majority of the cases the disease is diagnosed in the chronic phase, when the therapy is inefficient and the probability of cure is low. In addition, these drugs are highly toxic, with systemic side effects on patients. Trypanosoma cruzi has a metabolism largely based on the consumption of amino acids, mainly proline, aspartate and glutamate, which constitute the main carbon and energy sources in the insect stage of the parasite life cycle. These amino acids also participate in the differentiation process of the replicative non-infective form (epimastigote) to the non-replicative infective form (trypomastigote). In particular, the participation of proline in the intracellular differentiation cycle, which occurs in the mammalian host, was recently demonstrated. In addition, an arginine kinase has been described in T. cruzi and T. brucei, which converts free arginine to phosphoarginine, a phosphagen with a role as an energy reservoir. Arginine kinase seems to be an essential component of energy management during stress conditions. Taken together, these data indicate that amino acid metabolism may provide multiple as yet unexplored targets for therapeutic drugs.Fil: Silber, Ariel Mariano. Universidade de Sao Paulo; BrasilFil: Coli, Walter. Universidade de Sao Paulo; BrasilFil: Ulrich, Henning. Universidade de Sao Paulo; BrasilFil: Manso Alves, Maria. Universidade de Sao Paulo; BrasilFil: Pereira, Claudio Alejandro. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Médicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

    The ALICE experiment at the CERN LHC

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    ALICE (A Large Ion Collider Experiment) is a general-purpose, heavy-ion detector at the CERN LHC which focuses on QCD, the strong-interaction sector of the Standard Model. It is designed to address the physics of strongly interacting matter and the quark-gluon plasma at extreme values of energy density and temperature in nucleus-nucleus collisions. Besides running with Pb ions, the physics programme includes collisions with lighter ions, lower energy running and dedicated proton-nucleus runs. ALICE will also take data with proton beams at the top LHC energy to collect reference data for the heavy-ion programme and to address several QCD topics for which ALICE is complementary to the other LHC detectors. The ALICE detector has been built by a collaboration including currently over 1000 physicists and engineers from 105 Institutes in 30 countries. Its overall dimensions are 161626 m3 with a total weight of approximately 10 000 t. The experiment consists of 18 different detector systems each with its own specific technology choice and design constraints, driven both by the physics requirements and the experimental conditions expected at LHC. The most stringent design constraint is to cope with the extreme particle multiplicity anticipated in central Pb-Pb collisions. The different subsystems were optimized to provide high-momentum resolution as well as excellent Particle Identification (PID) over a broad range in momentum, up to the highest multiplicities predicted for LHC. This will allow for comprehensive studies of hadrons, electrons, muons, and photons produced in the collision of heavy nuclei. Most detector systems are scheduled to be installed and ready for data taking by mid-2008 when the LHC is scheduled to start operation, with the exception of parts of the Photon Spectrometer (PHOS), Transition Radiation Detector (TRD) and Electro Magnetic Calorimeter (EMCal). These detectors will be completed for the high-luminosity ion run expected in 2010. This paper describes in detail the detector components as installed for the first data taking in the summer of 2008
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