3,029 research outputs found

    Factorization scheme and scale dependence in diffractive dijet production at low Q^2

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    We calculate diffractive dijet production in deep-inelastic scattering at next-to-leading order of perturbative QCD, including contributions from direct and resolved photons, and compare our predictions to preliminary data from the H1 collaboration at HERA. We study how the cross section depends on the factorization scheme and scale M_\gamma at the virtual photon vertex for the occurrence of factorization breaking. The strong M_\gamma-dependence, which is present when only the resolved cross section is suppressed, is tamed by introducing the suppression also into the initial-state NLO correction of the direct part.Comment: 14 pages, 6 figure

    Miroslav Frýdek a kolektiv: Právní, náboženské a politické aspekty starověké římské rodiny

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    Recenze publikace - Miroslav Frýdek a kolektiv: Právní, náboženské a politické aspekty starověké římské rodiny1. vyd. Ostrava: KEY Publishing s.r.o., 2012, 122 s. ISBN 978-80-7418-157-

    Identification of small-molecule inhibitors of the antiapoptotic protein myeloid cell leukaemia-1 (Mcl-1)

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    Protein–protein interactions (PPIs) control many cellular processes in cancer and tumour growth. Of significant interest is the role PPIs play in regulating apoptosis. The overexpression of the antiapoptosis regulating Bcl-2 family of proteins is commonly observed in several cancers, leading to resistance towards both radiation and chemotherapies. From this family, myeloid cell leukemia-1 (Mcl-1) has proven the most difficult to target, and one of the leading causes of treatment resistance. Exploiting the selective PPI between the apoptosis-regulating protein Noxa and Mcl-1, utilising a fluorescence polarization assay, we have identified four small molecules with the ability to modulate Mcl-1. The identified compounds were computationally modelled and docked against the Mcl-1 binding interface to obtain structural information about their binding sites allowing for future analogue design. When examined for their activity towards pancreatic cell lines that overexpress Mcl-1 (MiaPaCa-2 and BxPC-3), the identified compounds demonstrated growth inhibition, suggesting effective Mcl-1 modulation

    Comparison of niti orthodontic archwires and a determination of the characteristic properties

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    The aim of this paper was to analyse the characteristic properties of six different, commercially available nickel-titanium orthodontic wires with a diameter of 0.305 mm (0.014"). The characteristic properties were determined by using semi-quantitative EDX analyses, DSC analyses for a determination of the phase temperatures, and a tensile test to obtain the mechanical properties of the wires. The investigation of the chemical composition showed an equiatomic NiTi alloy. Analyses of phase temperatures showed that the nickel-titanium orthodontic wires were, in an austenitic microstructure, exhibiting a superelastic effect in the oral environment. The uniaxial tensile stress strain curves showed different values for the beginning and the end of the transformation range during the loading

    Selective and potent proteomimetic inhibitors of intracellular protein–protein interactions

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    Inhibition of protein–protein interactions (PPIs) represents a major challenge in chemical biology and drug discovery. α-Helix mediated PPIs may be amenable to modulation using generic chemotypes, termed “proteomimetics”, which can be assembled in a modular manner to reproduce the vectoral presentation of key side chains found on a helical motif from one partner within the PPI. In this work, it is demonstrated that by using a library of N-alkylated aromatic oligoamide helix mimetics, potent helix mimetics which reproduce their biophysical binding selectivity in a cellular context can be identified

    Relative luminosity measurement of the LHC with the ATLAS forward calorimeter

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    In this paper it is shown that a measurement of the relative luminosity changes at the LHC may be obtained by analysing the currents drawn from the high voltage power supplies of the electromagnetic section of the forward calorimeter of the ATLAS detector. The method was verified with a reproduction of a small section of the ATLAS forward calorimeter using proton beams of known beam energies and variable intensities at the U-70 accelerator at IHEP in Protvino, Russia. The experimental setup and the data taking during a test beam run in April 2008 are described in detail. A comparison of the measured high voltage currents with reference measurements from beam intensity monitors shows a linear dependence on the beam intensity. The non-linearities are measured to be less than 0.5 % combining statistical and systematic uncertainties.Comment: 16 page

    Measurement of the Spin-Dependence of the pbar-p Interaction at the AD-Ring

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    We propose to use an internal polarized hydrogen storage cell gas target in the AD ring to determine for the first time the two total spin-dependent pbar-p cross sections sigma_1 and sigma_2 at antiproton beam energies in the range from 50 to 450 MeV. The data obtained are of interest by themselves for the general theory of pbar-p interactions since they will provide a first experimental constraint of the spin-spin dependence of the nucleon-antinucleon potential in the energy range of interest. In addition, measurements of the polarization buildup of stored antiprotons are required to define the optimum parameters of a future, dedicated Antiproton Polarizer Ring (APR), intended to feed a double-polarized asymmetric pbar-p collider with polarized antiprotons. Such a machine has recently been proposed by the PAX collaboration for the new Facility for Antiproton and Ion Research (FAIR) at GSI in Darmstadt, Germany. The availability of an intense stored beam of polarized antiprotons will provide access to a wealth of single- and double-spin observables, thereby opening a new window on QCD spin physics.Comment: 51 pages, 23 figures, proposal submitted to the SPS committee of CER

    Unveiling the "Three Finger Pharmacophore" required for p53-MDM2 Inhibition by Saturation Transfer Difference NMR Initial Growth Rates Approach

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    Inhibitors of the p53-MDM2 protein-protein interaction are emerging as a novel and validated approach to treating cancer. In this work we describe the synthesis and inhibitory evaluation of a series of isoquinolin-1-one analogues, and highlight the utility of an initial growth rates STD NMR approach supported by protein-ligand docking to investigate p53-MDM2 inhibition. The approach is illustrated by the study of compound 1, providing key insights into the binding mode of this kind of MDM2 ligands and, more importantly, readily unveiling the previously proposed three finger pharmacophore requirement for p53-MDM2 inhibition

    Forward pi^0 Production and Associated Transverse Energy Flow in Deep-Inelastic Scattering at HERA

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    Deep-inelastic positron-proton interactions at low values of Bjorken-x down to x \approx 4.10^-5 which give rise to high transverse momentum pi^0 mesons are studied with the H1 experiment at HERA. The inclusive cross section for pi^0 mesons produced at small angles with respect to the proton remnant (the forward region) is presented as a function of the transverse momentum and energy of the pi^0 and of the four-momentum transfer Q^2 and Bjorken-x. Measurements are also presented of the transverse energy flow in events containing a forward pi^0 meson. Hadronic final state calculations based on QCD models implementing different parton evolution schemes are confronted with the data.Comment: 27 pages, 8 figures and 3 table

    Search for Doubly-Charged Higgs Boson Production at HERA

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    A search for the single production of doubly-charged Higgs bosons H^{\pm \pm} in ep collisions is presented. The signal is searched for via the Higgs decays into a high mass pair of same charge leptons, one of them being an electron. The analysis uses up to 118 pb^{-1} of ep data collected by the H1 experiment at HERA. No evidence for doubly-charged Higgs production is observed and mass dependent upper limits are derived on the Yukawa couplings h_{el} of the Higgs boson to an electron-lepton pair. Assuming that the doubly-charged Higgs only decays into an electron and a muon via a coupling of electromagnetic strength h_{e \mu} = \sqrt{4 \pi \alpha_{em}} = 0.3, a lower limit of 141 GeV on the H^{\pm\pm} mass is obtained at the 95% confidence level. For a doubly-charged Higgs decaying only into an electron and a tau and a coupling h_{e\tau} = 0.3, masses below 112 GeV are ruled out.Comment: 15 pages, 3 figures, 1 tabl
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