788 research outputs found

    Melatonin reduces the severity of experimental amoebiasis

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    <p>Abstract</p> <p>Background</p> <p>Melatonin has immunomodulatory effects but very little is known about its influence in protozoan infections, such as <it>Entamoeba histolytica</it>, which causes amoebiasis, a disease with significant morbidity and mortality. In this study, we evaluated the effects of exogenous melatonin interference in experimental amoebiasis and on interactions between human blood cells and <it>E. histolytica </it>trophozoites.</p> <p>Methods</p> <p>The effect of melatonin was investigated in models of experimental amoebiasis in hamsters and rats by evaluating the area of necrosis induced by <it>E. histolytica</it>. The activity of melatonin on the interactions between leukocytes and amoebae was determined by examining leukophagocytosis. For <it>in vitro </it>tests, polymorphonuclear and mononuclear human blood leucocytes were incubated with <it>E. histolytica </it>trophozoites.</p> <p>Results</p> <p>The areas of amoebic necrosis were significantly reduced in animals treated with melatonin. Melatonin treatment increased leukophagocytosis but was associated with a greater number of dead amoebae.</p> <p>Conclusions</p> <p>These results suggest that melatonin may play a beneficial role in the control of amoebic lesions, raising the possibility that this drug may be used as an adjuvant in anti-amoebic therapy.</p

    Sistema de Controle da Pesca de Mato Grosso do Sul SCPESCA/MS 7 - 2000.

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    Neste estudo encontram-se as informaçÔes sobre a pesca profissional e esportiva coletadas e analisadas pelo SISTEMA DE CONTROLE DA PESCA DE MATO GROSSO DO SUL - SCPESCA/MS em 2000, obtidas para todo o pescado capturado na Bacia do Alto Paraguai - BAP, oficialmente vistoriado pela PolĂ­cia Militar Ambiental/MS e desembarcado no Estado. Foi registrado um total de 934t de pescado, onde 33% (306 t) correspondem Ă  pesca profissional e 67% (628 t) Ă  esportiva. As espĂ©cies mais capturadas foram: pintado Pseudoplatystoma corruscans (178t; 22,3%), pacu Piaractus mesopotamicus (158 t; 19,8%) e cachara Pseudoplatystoma fasciatum (140 t; 17,6%). Os rios que mais contribuĂ­ram foram Paraguai (380 t; 47,6%) e Miranda (179 t; 22,5%). Um total de 42.847 pescadores esportivos visitou o estado de Mato Grosso do Sul, concentrado sobretudo em setembro e outubro, provenientes principalmente de SĂŁo Paulo (63%). Mensalmente, em mediana, os pescadores profissionais capturaram entre 59,6 e 82,5 kg/pescador.viagem e entre 7,0 e 12,0 kg/pescador.dia, pescado durante 6 a 11 dias/pescaria; os pescadores esportivos capturaram entre 13,5 e 16,0 kg/pescador.viagem e entre 2,8 e 3,8 kg/pescador.dia, pescando durante 4 a 5 dias/pescaria. Comparando-se os dados dos anos de 1994 a 2000, obteve-se um perfil da pesca, identificando-se suas principais tendĂȘncias.bitstream/item/37414/1/BP38.pd

    Acceleration from M theory and Fine-tuning

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    The compactification of M theory with time dependent hyperbolic internal space gives an effective scalar field with exponential potential which provides a transient acceleration in Einstein frame in four dimensions. Ordinary matter and radiation are present in addition to the scalar field coming from compactification. We find that we have to fine-tune the initial conditions of the scalar field so that our Universe experiences acceleration now. During the evolution of our Universe, the volume of the internal space increases about 12 times. The time variation of the internal space results in a large time variation of the fine structure constant which violates the observational constraint on the variation of the fine structure constant. The large variation of the fine structure constant is a generic feature of transient acceleration models.Comment: 9 pages, 3 figures, use iopart, v2; references updated, accepted for publication in Class. Quantum Gra

    Antioxidant activity of jacaranda decurrens Cham.

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    Many diseases and related degenerative processes including heart, cĂąncer and Parkinson diseases are associated with rcactive oxygen species (ROS). In an effort Io preveni diseases, search for com-pounds with antioxidant activity hĂĄs been a major interestof dif-ferent research groups in natural products research. The objective of this research was to investigatethe antioxidant activity of EtOH leaf extract ofjacarando decurrrens and its fractions using the 2,2-diphenyl-2-picrylhydrazyl hydrate (DPPH) assay [lJ, that uses s pĂ© ciro me t ric method to determine radical scavenging activity, Rutinattheconcçntrationof l.Omg-L was used as the standard. Our results ha vĂȘ shown lhat crude extract and fractions had anti-oxidant activities mainly if tested at concentrations of 5.0 to 10.0mg-L. such activities, however. were lesser or equal to the standard (Table 1). The triterpenes, ursolic and oleanohc acids, were detected in the crude extract, Jd-1 and Jd-2, Possibly, these triterpenes are the active constituents responsible for the antioxi-dant activity |2j. At lower concentrations (0,6mg-L than the standard. Jd-3 fraction was the most active. The presenceof flavo-noids and glycosilated compounds were detected in jcl-3 fraction (2], This is the first attempt to demonstrate antioxidant activities found i n JĂĄ cara n (ia decurrens leaf extracts. Acknowledgements. Re-search funded by FAPESP. The State of SĂŁo Paulo Research Founda-tion. Brazil, Referentes: 11) Koleva I. et ai. (2002). Phytochem Anal. 13: 8-17, (2! Oh CJ, et ai. (2007)- Free Radie RĂ©s. 41(6): 638-44

    Universal and nonuniversal contributions to block-block entanglement in many-fermion systems

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    We calculate the entanglement entropy of blocks of size x embedded in a larger system of size L, by means of a combination of analytical and numerical techniques. The complete entanglement entropy in this case is a sum of three terms. One is a universal x and L-dependent term, first predicted by Calabrese and Cardy, the second is a nonuniversal term arising from the thermodynamic limit, and the third is a finite size correction. We give an explicit expression for the second, nonuniversal, term for the one-dimensional Hubbard model, and numerically assess the importance of all three contributions by comparing to the entropy obtained from fully numerical diagonalization of the many-body Hamiltonian. We find that finite-size corrections are very small. The universal Calabrese-Cardy term is equally small for small blocks, but becomes larger for x>1. In all investigated situations, however, the by far dominating contribution is the nonuniversal term steming from the thermodynamic limit.Comment: 6 pages, 3 figure

    Interacting Constituents in Cosmology

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    Universe evolution, as described by Friedmann's equations, is determined by source terms fixed by the choice of pressure ×\times energy-density equations of state p(ρ)p(\rho). The usual approach in Cosmology considers equations of state accounting only for kinematic terms, ignoring the contribution from the interactions between the particles constituting the source fluid. In this work the importance of these neglected terms is emphasized. A systematic method, based on the Statistical Mechanics of real fluids, is proposed to include them. A toy-model is presented which shows how such interaction terms can engender significant cosmological effects.Comment: 24 pages, 6 figures. It includes results presented in "Cosmic Acceleration from Elementary Interactions" [arXiv:gr-qc/0512135]. Citations added in v.
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