948,945 research outputs found

    Neem oil nanoemulsions: characterisation and antioxidant activity

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    The aim of the present work is to develop nanoemulsions (NEs), nanosized emulsions, manufactured for improving the delivery of active pharmaceutical ingredients. In particular, nanoemulsions composed of Neem seed oil, contain rich bioactive components, and Tween 20 as nonionic surfactant were prepared. A mean droplet size ranging from 10 to 100nm was obtained by modulating the oil/surfactant ratio. Physicochemical characterisation was carried out evaluating size, f-potential, microviscosity, polarity and turbidity of the external shell and morphology, along with stability in simulated cerebrospinal fluid (CSF), activity of Neem oil alone and in NEs, HEp-2 cell interaction and cytotoxicity studies. This study confirms the formation of NEs by Tween 20 and Neem oil at different weight ratios with small and homogenous dimensions. The antioxidant activity of Neem oil alone and in NEs was comparable, whereas its cytotoxicity was strongly reduced when loaded in NEs after interaction with HEp-2 cells

    Dynamics of a linear beam with an attached local nonlinear energy sink

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    We provide numerical evidence of passive and broadband targeted energy transfer from a linear flexible beam under shock excitation to a local essentially nonlinear lightweight attachment that acts, in essence, as nonlinear energy sink—NES. It is shown that the NES absorbs shock energy in a one-way, irreversible fashion and dissipates this energy locally, without 'spreading' it back to the linear beam. Moreover, we show numerically that an appropriately designed and placed NES can passively absorb and locally dissipate a major portion of the shock energy of the beam, up to an optimal value of 87%. The implementation of the NES concept to the shock isolation of practical engineering structures and to other applications is discussed

    On what we experience when we hear people speak

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    According to perceptualism, fluent comprehension of speech is a perceptual achievement, in as much as it is akin to such high-level perceptual states as the perception of objects as cups or trees, or of people as happy or sad. According to liberalism, grasp of meaning is partially constitutive of the phenomenology of fluent comprehension. I here defend an influential line of argument for liberal perceptualism, resting on phenomenal contrasts in our comprehension of speech, due to Susanna Siegel and Tim Bayne, against objections from Casey O'Callaghan and Indrek Reiland. I concentrate on the contrast between the putative immediacy of meaning-assignment in fluent comprehension, as compared with other, less ordinary, perhaps translation-based ways of getting at the meaning of speech. I argue this putative immediacy is difficult to capture on a non-perceptual view (whether liberal or non-liberal), and that the immediacy in question has much in common with that which applies in other, less controversial cases of high-level perception

    Stability of Mixed-Strategy-Based Iterative Logit Quantal Response Dynamics in Game Theory

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    Using the Logit quantal response form as the response function in each step, the original definition of static quantal response equilibrium (QRE) is extended into an iterative evolution process. QREs remain as the fixed points of the dynamic process. However, depending on whether such fixed points are the long-term solutions of the dynamic process, they can be classified into stable (SQREs) and unstable (USQREs) equilibriums. This extension resembles the extension from static Nash equilibriums (NEs) to evolutionary stable solutions in the framework of evolutionary game theory. The relation between SQREs and other solution concepts of games, including NEs and QREs, is discussed. Using experimental data from other published papers, we perform a preliminary comparison between SQREs, NEs, QREs and the observed behavioral outcomes of those experiments. For certain games, we determine that SQREs have better predictive power than QREs and NEs

    Acquaintance, Conceptual Capacities, and Attention

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    Russell’s theory of acquaintance construes perceptual awareness as at once constitutively independent of conceptual thought and yet a source of propositional knowledge. Wilfrid Sellars, John McDowell, and other conceptualists object that this is a ‘myth’: perception can be a source of knowledge only if conceptual capacities are already in play therein. Proponents of a relational view of experience, including John Campbell, meanwhile voice sympathy for Russell’s position on this point. This paper seeks to spell out, and defend, a claim that offers the prospects for an attractive, unacknowledged element of common ground in this debate. The claim is that conceptual capacities, at least in a certain minimal sense implicit in McDowell’s recent work, must be operative in perceptual experience, if it is to rationalize judgement. The claim will be supported on the basis of two premises, each of which can be defended drawing, inter alia, on considerations stressed by Campbell. First, that experience rationalizes judgement only if it is attentive. Second, that attention qualifies as a conceptual capacity, in the noted, minimal sense. The conjunction of the two premises might be dubbed ‘attentional conceptualism’

    Gamma Radiation by Neutralino Stars

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    A new model of gamma radiation (GR) generated by neutralino annihilation in neutralino stars (NeS) is proposed. Diffuse Galactic and extragalactic GR is calculated for this model and is shown to be in a reasonable agreement with observations. The point source component (P) is picked out among nonidentified discrete gamma sources from EGRET catalog. This component is shown to be distributed isotropically and homogeneously, as it should be for NeS. Gamma radiation from significant part of P-sources is supposed to be the direct radiation from individual NeS. This supposition is shown to be in agreement with observations. The comparison of the theory with observed GR gives a possibility to establish some important features of CDM particle.Comment: 12 pages, LaTe
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