400 research outputs found

    Thermo-alkali-stable catalases from newly isolated Bacillus sp. for the treatment and recycling of textile bleaching effluents

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    Three thermoalkaliphilic bacteria, which were grown at pH 9.3–10 and 60–65 °C were isolated out of a textile wastewater drain. The unknown micro-organisms were identified as thermoalkaliphilic Bacillus sp. Growth nditions were studied and catalase activities and stabilities compared. Catalases from Bacillus SF showed high stabilities at 60 °C and pH 9 (t1/2=38 h) and thus this strain was chosen for further investigations, such as electron microscopy, immobilization of catalase and hydrogen peroxide degradation studies. Degradation of hydrogen peroxide with an immobilized catalase from Bacillus SF enabled the reuse of the water for the dyeing process. In contrast, application of the free enzyme for treatment of bleaching effluents, caused interaction between the denaturated protein and the dye, resulting in reduced dye uptake, and a higher color difference of 1.3 ΔE* of dyed fabrics compared to 0.9 ΔE* when using the immobilized enzyme

    Development and operational experience of magnetic horn system for T2K experiment

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    A magnetic horn system to be operated at a pulsed current of 320 kA and to survive high-power proton beam operation at 750 kW was developed for the T2K experiment. The first set of T2K magnetic horns was operated for over 12 million pulses during the four years of operation from 2010 to 2013, under a maximum beam power of 230 kW, and 6.63×10206.63\times10^{20} protons were exposed to the production target. No significant damage was observed throughout this period. This successful operation of the T2K magnetic horns led to the discovery of the νμνe\nu_{\mu}\rightarrow\nu_e oscillation phenomenon in 2013 by the T2K experiment. In this paper, details of the design, construction, and operation experience of the T2K magnetic horns are described.Comment: 22 pages, 40 figures, also submitted to Nuclear Instrument and Methods in Physics Research,

    Protein disulphide isomerase-assisted functionalization of keratin-based matrices

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    In living systems, protein disulphide isomerase (PDI, EC 5.3.4.1) regulates the formation of new disulphide bonds in proteins (oxidase activity) and catalyzes the rearrangement of non-native disulphide bonds (isomerase activity), leading proteins towards their native configuration. In this study, PDI was used to attach cysteine-containing compounds (CCCs) onto hair, to enhance compound migration within hair fibre and to trigger protein release. A fluorescent (5(6)-TAMRA)-labelled keratin peptide was incorporated into hair by using PDI. Similarly, PDI promoted the grafting of a cysteine-functionalized dye onto wool, as suggested by matrix-assisted laser desorption and ionization time-of-flight results. These reactions were thought to involve oxidation of disulphide bonds between CCCs and wool or hair cysteine residues, catalyzed by the oxidized PDI active site. On the other hand, PDI was demonstrated to enhance the migration of a disulphide bondfunctionalized dye within the keratin matrix and trigger the release of RNase A from wool fibres’ surface. These observations may indicate that an isomerisation reaction occurred, catalyzed by the reduced PDI active site, to achieve the thiol-disulphide exchange, i.e. the rearrangement of disulphide bonds between CCCs and keratin. The present communication aims to highlight promising biotechnological applications of PDI, derived from its almost unique properties within the isomerase family.We thank to FCT "Fundacao para a Ciencia e Tecnologia" (scholarship SFRH/BD/38363/2007) for providing Margarida Fernandes the grant for PhD studies

    A Precise Determination of Electroweak Parameters in Neutrino-Nucleon Scattering

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    The NuTeV collaboration has extracted sin^2theta_W from the ratios of neutral current to charged current neutrino and anti-neutrino cross-sections. Our value, sin^2theta_W(on-shell)=0.2277+/-0.0013(stat)+/-0.0009(syst), is three standard deviations above the standard model prediction. We also present a model independent analysis of the same data.Comment: ReVTeX, 5 pp, 1fig; v2. revised SM prediction; v3. more sig. digits in Eqns 6-7, fix error in Eqn

    A Search for Electron Antineutrino Appearance at the Δm2\Delta m^2 \sim 1 eV2\mathrm{eV}^{2} Scale

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    The MiniBooNE Collaboration reports initial results from a search for νˉμνˉe\bar{\nu}_{\mu}\to\bar{\nu}_e oscillations. A signal-blind analysis was performed using a data sample corresponding to 3.39×10203.39 \times 10^{20} protons on target. The data are consistent with background prediction across the full range of neutrino energy reconstructed assuming quasielastic scattering, 200<EνQE<3000200 < E_{\nu}^{QE} < 3000 MeV: 144 electron-like events have been observed in this energy range, compared to an expectation of 139.2±17.6139.2 \pm 17.6 events. No significant excess of events has been observed, both at low energy, 200-475 MeV, and at high energy, 475-1250 MeV. The data are inconclusive with respect to antineutrino oscillations suggested by data from the Liquid Scintillator Neutrino Detector at Los Alamos National Laboratory.Comment: 5 pages, 3 figures, 2 table

    A Search for Muon-neutrino to Electron-neutrino and Muon-antineutrino to Electron-antineutrino Oscillations at NuTeV

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    Limits on νμνe\nu_\mu \to \nu_e and νˉμνˉe\bar\nu_\mu \to \bar\nu_e oscillations are extracted using the NuTeV detector with sign-selected νμ\nu_\mu and \nub_\mu beams. In \nub_\mu mode, for the case of sin22α=1\sin^2 2\alpha = 1, Δm2>2.6\Delta m^2 > 2.6 eV2{\rm eV^2} is excluded, and for Δm21000\Delta m^2 \gg 1000 eV2{\rm eV^2}, sin22α>1.1×103\sin^2 2\alpha > 1.1 \times 10^{-3}. The NuTeV data exclude the high Δm2\Delta m^2 end of νˉμνˉe\bar\nu_\mu \to \bar\nu_e oscillations parameters favored by the LSND experiment without the need to assume that the oscillation parameters for ν\nu and \nub are the same. We present the most stringent experimental limits for νμ(νˉμ)νe(νˉe)\nu_\mu (\bar{\nu}_\mu) \to \nu_e (\bar{\nu}_e) oscillations in the large Δm2\Delta m^2 region.Comment: 4 pages, 3 figures. Submitted to Phys. Rev. Letters, UR-164
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