3,099 research outputs found

    The media perspective in the study of scientific abstraction

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    Force and its measure

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    THE INHIBITORY EFFECT OF PROPOLIS AND CAFFEIC ACID PHENETHYLESTER ON CYCLOOXYGENASE ACTIVITY IN J774 MACROPHAGES.

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    The effect of an ethanolic extract of propolis, with and without CAPE, and some of its components on cyclooxygenase (COX-1 and COX-2) activity in J774 macrophages has been investigated. COX-1 and COX-2 activity, measaured as prostaglandin E-2 (PGE(2)) production, were concentration-dependently inhibited by propolis (C x 10(-3)-3 x 10(2) mugml(-1)) with an IC50 of 2.7 mugml(-1) and 4.8 x 10(-2) mugml(-1), respectively. Among the compounds tested pinocembrin and caffeic, ferulic, cinnamic and chlorogenic acids did not affect the activity of COX isoforms. Conversely, CAPE (2.8 x 10(-4)-28 mugml(-1); 10(-9)-10(-4) M) and galangin (2.7 x 10(-4)-27 mugml(-1); 10(-9)-10(-4) M) were effective, the last being about ten-twenty times less potent. In fact the IC50 of CAPE for COX-1 and COX-2 were 4.4 x 10(-1) mugml(-1) (1.5 x 10(-6) M) and 2 x 10(-3) mugml(-1) (6.3 x 10(-9) M), respectively. The IC50 of galangin were 3.7 mugml(-1) (15 x 10(-6) M) and 3 x 10(-2) mugml(-1) (120 x 10(-1) M), for COX-1 and COX-2 respectively. To better investigate the role of CAPE, we tested the action of the ethanolic extract of propolis deprived of CAPE, which resulted about ten times less potent than the extract with CAPE in the inhibition of both COX-1 and COX-2, with an IC50 of 30 mugml(-1) and 5.3 x 10(-1) mugml(-1), respectively. Moreover the comparison of the inhibition curves showed a significant difference (p < 0.001). These results suggest that both CAPE and galangin contribute to the overall activity of propolis, CAPE being more effective

    Stationary entanglement in N-atom subradiant degenerate cascade systems

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    We address ultracold NN-atom degenerate cascade systems and show that stationary subradiant states, already observed in the semiclassical regime, also exist in a fully quantum regime and for a small number of atoms. We explicitly evaluate the amount of stationary entanglement for the two-atom configuration and show full inseparability for the three-atom case. We also show that a continuous variable description of the systems is not suitable to detect entanglement due to the nonGaussianity of subradiant states.Comment: 4 figure

    Dynamics of radiationless transitions in large molecular systems: a Franck- Condon-based method accounting for displacements and rotations of all normal coordinates

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    Beautiful Baryons from Lattice QCD

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    We perform a lattice study of heavy baryons, containing one (Λb\Lambda_b) or two bb-quarks (Ξb\Xi_b). Using the quenched approximation we obtain for the mass of Λb\Lambda_b MΛb=5.728±0.144±0.018GeV. M_{\Lambda_b}= 5.728 \pm 0.144 \pm 0.018 {\rm GeV}. The mass splitting between the Λb\Lambda_b and the B-meson is found to increase by about 20\% if the light quark mass is varied from the chiral limit to the strange quark mass.Comment: 11 pages, Figures obtained upon request from [email protected]

    La elaboración de la pureza en los procedimientos asiro-babilónicos: El tiempo, el espacio y el mundo material

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    Assyro-Babylonian procedural texts for making cult objects dated to the 1st millennium BCE provide an untapped resource for examining scribal conceptions of craft and purity in the ancient world. Ritual procedures for “opening of the mouth” of a cult statue (mīs pî), and for manufacturing a ritual drum called the lilissu, constitute the principal focus of this two-part study. This work uses three themata – time, space, and the material world – to provide the scaffolding for a comparative analysis that spans various centuries and localities, highlighting the ways in which “purity” was crafted in cuneiform scholarly cultures.Los textos procesales asirio-babilónicos para la fabricación de objetos de culto que datan del primer milenio a.C. proporcionan un recurso no explotado para examinar las concepciones de los escribas sobre la artesanía y la pureza en el mundo antiguo. Los procedimientos rituales para “abrir la boca” de una estatua de culto (mīs pî) y para fabricar un tambor ritual llamado lilissu constituyen el enfoque principal de este estudio de dos partes. Este trabajo utiliza tres themata (tiempo, espacio y mundo material) para proporcionar el andamiaje para un análisis comparativo que abarca varios siglos y localidades, destacando las formas en que la “pureza” se forjó en las culturas académicas cuneiformes

    Ion-Exchanged Waveguides in Glass Doped with PbS Quantum Dots

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    The lowest-loss (≤1 dB/cm) ion-exchanged waveguides in glass doped with PbS quantum dots are presented. Near-field mode profile and refractive index profile using the refracted near-field technique were measured for these waveguides. We demonstrate that the optical properties of this glass unchanged during the ion-exchange process

    Witnessing entanglement in hybrid systems

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    We extend the definition of entanglement witnesses based on structure factors to the case in which the position of the scatterers is quantized. This allows us to study entanglement detection in hybrid systems. We provide several examples that show how these extra degrees of freedom affect the detection of entanglement by directly contributing to the measurement statistics. We specialize the proposed witness operators for a chain of trapped ions. Within this framework, we show how the collective vibronic state of the chain can act as an undesired quantum environment and how ions quantum motion can affect the entanglement detection. Finally, we investigate some specific cases where the method proposed leads to detection of hybrid entanglement.Comment: 6 pages, 4 figure
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