34 research outputs found

    APHRODITE: Design and Preliminary Tests of an Autonomous and Reusable Photo-sensing Device for Immunological Test aboard the International Space Station

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    Preliminary results of the design and manufacturing of APHRODITE, a compact and versatile device for carrying out analyses of biological fluids during space missions that will be used as a technological demonstrator on board the International Space Station (ISS) for the quantitative determination of salivary biomarkers indicators of alterations of functionality of the immune system. The paper addresses the design of the main subsystems of the analytical device and the preliminary results obtained during the first implementations of the device subsystems and testing measurements. In particular, the system design and the experiment data output of the lab-on-chip photosensors and of the front-end readout electronics are reported in detail

    Thermodynamic study of aqueous micellar solutions of biologically active bisquaternary ammonium chlorides

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    Thermodynamic properties of aqueous solution of bisquaternary ammonium salts, which are derivatives of N,N-bisdimethyl-1,2-ethanediamine ( bis-Cn-BEC) , of general formula /CnH2n/1OOCCH2(CH3)2N!CH2CH2N!(CH3)2CH2COOCn-H /2Cl0(bis-Cn-BEC, where the subscript n stands for the number of carbon atoms of the alkyl chain bound to the carboxyl group) are here reported and compared with those of the corresponding monomers. Dilution enthalpies have been measured by means of a flow type microcalorimeter at 313 K, and densities have been measured by means of a vibrating tube densimeter at 298 K. Apparent and partial molar quantities have been obtained from the experimental data and expressed as a function of molality assuming the infinite dilution as standard state. The changes in enthalpy and in volume upon micellization have been evaluated by assuming the pseudo-phase transition model. From the calculated enthalpy changes at 313 K and that previously reported at 298 K, the changes in heat capacity for micellization has been evaluated. The data suggest the hypothesis that the alkyl chain in the dimers are already partially associated in solution. Moreover, the trends of the cmc as a function of the chain length for monomers and dimers suggest that the association of the chains probably leaves out the first three methylene groups of the alkyl chains bound to the carboxylic groups. The packing parameter, P, gives 0.37 for bis-C10-BEC, and the formation of rod-like micelles is therefore suggested

    Zingiberaceae endémicas del Perú

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    The Zingiberaceae family are represented in Peru with three genera and 19 species (Brako & Zarucchi, 1993; Ulloa Ulloa et al., 2004), all herbaceous plants. Here we recognize one endemic species, occurring in the lower limits of the Humid Premontane Forest region, between 700 and 800 m elevation. The species has not yet been reported from within a protected area.La familia Zingiberaceae es reconocida en el Perú por presentar tres géneros y 19 especies (Brako & Zarucchi, 1993; Ulloa Ulloa et al., 2004), todas hierbas. En este trabajo reconocemos un endemismo. Este taxón endémico ha sido encontrado en sectores inferiores de la región del Bosque Húmedo Premontano, entre los 700 y 800 m de altitud. No se encuentra representada dentro de áreas naturales protegidas
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