1,147 research outputs found

    Antibody validation of immunohistochemistry for biomarker discovery: Recommendations of a consortium of academic and pharmaceutical based histopathology researchers

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    As biomarker discovery takes centre-stage, the role of immunohistochemistry within that process is increasing. At the same time, the number of antibodies being produced for ‘‘research use’’ continues to rise and it is important that antibodies to be used as biomarkers are validated for specificity and sensitivity before use. This guideline seeks to provide a stepwise approach for the validation of an antibody for immunohistochemical assays, reflecting the views of a consortium of academic and pharmaceutical based histopathology researchers. We propose that antibodies are placed into a tier system, level 1–3, based on evidence of their usage in immunohistochemistry, and that the degree of validation required is proportionate to their place on that tier

    Extreme High-Field Superconductivity in Thin Re Films

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    We report the high-field superconducting properties of thin, disordered Re films via magneto-transport and tunneling density of states measurements. Films with thicknesses in the range of 9 nm to 3 nm had normal state sheet resistances of ∼\sim0.2 kΩ\Omega to ∼\sim1 kΩ\Omega and corresponding transition temperatures in the range of 6 K to 3 K. Tunneling spectra were consistent with those of a moderate coupling BCS superconductor. Notwithstanding these unremarkable superconducting properties, the films exhibited an extraordinarily high upper critical field. We estimate their zero-temperature Hc2H_{c2} to be more than twice the Pauli limit. Indeed, in 6 nm samples the estimated reduced critical field Hc2/Tc∼H_{c2}/T_c\sim 5.6 T/K is among the highest reported for any elemental superconductor. Although the sheet resistances of the films were well below the quantum resistance RQ=h/4e2R_Q=h/4e^2, their Hc2H_{c2}'s approached the theoretical upper limit of a strongly disordered superconductor for which kFℓ∼1k_F\ell\sim1.Comment: 12 pages, 10 figure

    The Distribution, Excitation and Formation of Cometary Molecules: Methanol, Methyl Cyanide and Ethylene Glycol

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    We present an interferometric and single dish study of small organic species toward Comets C/1995 O1 (Hale-Bopp) and C/2002 T7 (LINEAR) using the BIMA interferometer at 3 mm and the ARO 12m telescope at 2 mm. For Comet Hale-Bopp, both the single-dish and interferometer observations of CH3OH indicate an excitation temperature of 105+/-5 K and an average production rate ratio Q(CH3OH)/Q(H2O)~1.3% at ~1 AU. Additionally, the aperture synthesis observations of CH3OH suggest a distribution well described by a spherical outflow and no evidence of significant extended emission. Single-dish observations of CH3CN in Comet Hale-Bopp indicate an excitation temperature of 200+/-10 K and a production rate ratio of Q(CH3CN)/Q(H2O)~0.017% at ~1 AU. The non-detection of a previously claimed transition of cometary (CH2OH)2 toward Comet Hale-Bopp with the 12m telescope indicates a compact distribution of emission, D<9'' (<8500 km). For the single-dish observations of Comet T7 LINEAR, we find an excitation temperature of CH3OH of 35+/-5 K and a CH3OH production rate ratio of Q(CH3OH)/Q(H2O)~1.5% at ~0.3 AU. Our data support current chemical models that CH3OH, CH3CN and (CH2OH)2 are parent nuclear species distributed into the coma via direct sublimation off cometary ices from the nucleus with no evidence of significant production in the outer coma.Comment: accepted for publication in Ap

    State-of-the-art in lean design engineering:a literature review on white collar lean

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    Lean is usually associated with the ‘operations’ of a manufacturing enterprise; however, there is a growing awareness that these principles may be transferred readily to other functions and sectors. The application to knowledge-based activities such as engineering design is of particular relevance to UK plc. Hence, the purpose of this study has been to establish the state-of-the-art, in terms of the adoption of Lean in new product development, by carrying out a systematic review of the literature. The authors' findings confirm the view that Lean can be applied beneficially away from the factory; that an understanding and definition of value is key to success; that a set-based (or Toyota methodology) approach to design is favoured together with the strong leadership of a chief engineer; and that the successful implementation requires organization-wide changes to systems, practices, and behaviour. On this basis it is felt that this review paper provides a useful platform for further research in this topic

    Position-sensitive detection of ultracold neutrons with an imaging camera and its implications to spectroscopy

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    Position-sensitive detection of ultracold neutrons (UCNs) is demonstrated using an imaging charge-coupled device (CCD) camera. A spatial resolution less than 15 μ\mum has been achieved, which is equivalent to an UCN energy resolution below 2 pico-electron-volts through the relation δE=m0gδx\delta E = m_0g \delta x. Here, the symbols δE\delta E, δx\delta x, m0m_0 and gg are the energy resolution, the spatial resolution, the neutron rest mass and the gravitational acceleration, respectively. A multilayer surface convertor described previously is used to capture UCNs and then emits visible light for CCD imaging. Particle identification and noise rejection are discussed through the use of light intensity profile analysis. This method allows different types of UCN spectroscopy and other applications.Comment: 12 figures, 28 pages, accepted for publication in NIM

    Measurement of the neutron lifetime using an asymmetric magneto- gravitational trap and in situ detection

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    The precise value of the mean neutron lifetime, τn\tau_n, plays an important role in nuclear and particle physics and cosmology. It is a key input for predicting the ratio of protons to helium atoms in the primordial universe and is used to search for new physics beyond the Standard Model of particle physics. There is a 3.9 standard deviation discrepancy between τn\tau_n measured by counting the decay rate of free neutrons in a beam (887.7 ±\pm 2.2 s) and by counting surviving ultracold neutrons stored for different storage times in a material trap (878.5±\pm0.8 s). The experiment described here eliminates loss mechanisms present in previous trap experiments by levitating polarized ultracold neutrons above the surface of an asymmetric storage trap using a repulsive magnetic field gradient so that the stored neutrons do not interact with material trap walls and neutrons in quasi-stable orbits rapidly exit the trap. As a result of this approach and the use of a new in situ neutron detector, the lifetime reported here (877.7 ±\pm 0.7 (stat) +0.4/-0.2 (sys) s) is the first modern measurement of τn\tau_n that does not require corrections larger than the quoted uncertainties.Comment: 9 pages, 3 figures, 2 table
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