235 research outputs found

    Разработка отклонителя для управления направлением скважин при ударно-вращательном бурении

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    Die Kombination einer Membran mit einer katalytischen Reaktion in einem Membranreaktor ist eines der Konzepte multifunktionaler Reaktoren zur Prozessintensivierung. Eine industriell besonders interessante Anwendung ist dabei die Darstellung von Synthesegas durch partielle Oxidation von Methan zu Kohlenmonoxid und Wasserstoff, wobei der Sauerstoff durch eine gemischtleitende Perowskit-Membran aus Luft zudosiert wird. Es ist gelungen, entsprechende Perowskit-Membranen als Hohlfasern mit einer volumenbezogenen Membranfläche von bis zu 500 m<sup>2</sup>/m<sup>3</sup> durch einen ökonomischen Spinnprozess zu entwickeln. Unter Laborbedingungen konnten langzeitstabil Synthesegas (CO, H<sub>2</sub>) mit einer CO-Selektivität von 95 % bei 95 % CH<sub>4</sub>-Umsatz erzeugt und die Ergebnisse durch eine detaillierte mathematische Modellierung beschrieben werden. Copyright © 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim [accessed February 8th 2013

    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

    Identification of a common recognition center for a photoactive non-steroidal antiinflammatory drug in serum albumins of different species

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    [EN] The non-steroidal anti-inflammatory drug (S)-carprofen (CPF) has been used as a photoactive probe to investigate the possible existence of a common recognition center in serum albumins (SAs) of different species. The methodology involves irradiation of the CPF/SA complexes, coupled with gel filtration chromatography or proteomic analysis of the photolysates, docking and molecular dynamics simulations. Photolysis of CPF/SA complexes at = 320 nm, and gel filtration chromatography, revealed that the protein fraction still contained the drug fluorophore, in agreement with covalent attachment of the photogenerated radical intermediate CBZ to SAs. After trypsin digestion and ESI-MS/MS, the incorporation of CBZ was detected at several positions in the different albumins. Remarkably, modifications at the IB/IIIA interface were observed in all cases (Tyr452 in HSA, RbSA and RtSA and Tyr451 in BSA, PSA and SSA). The molecular basis of this common recognition, studied by docking and molecular dynamics simulation studies on the corresponding non-covalent complexes, corroborated the experimentally observed covalent modifications. Our computational studies also revealed that the previously reported displacement of CPF by (S)-ibuprofen, a site II specific drug, would be due to an allosteric effect in site II, rather than a direct molecular displacement, as expected.Financial support from the Spanish Ministry of Economy and Competiveness (CTQ2016-78875-P, SAF2016-75638-R and BES-2014-069404), Generalitat Valenciana (PROMETEO2017/075), Conselleria de Cultura, Educacion e Ordenacion Universitaria (Centro singular de investigacion de Galicia accreditation 2016-2019, ED431G/09) and the European Regional Development Fund (ERDF) is acknowledged. This work was also supported by Instituto de Salud Carlos III (ISCIII) co-funded by Fondo Europeo de Desarrollo Regional FEDER for the Thematic Networks and Co-operative Research Centres: ARADyAL (RD16/0006/0030). EL thanks the Xunta de Galicia for his postdoctoral fellowship. We are also grateful to the Centro de Supercomputacion de Galicia (CESGA) for use of the Finis Terrae II supercomputer. The proteomic analysis was performed in the proteomics facility of SCSIE University of Valencia that belongs to ProteoRed PRB2-ISCIII and is supported by grant PT13/0001, of the PE I+D+I 2013-2016, funded by ISCIII and FEDER.Molins-Molina, O.; Lence, E.; Limones-Herrero, D.; González-Bello, C.; Miranda Alonso, MÁ.; Jiménez Molero, MC. (2019). Identification of a common recognition center for a photoactive non-steroidal antiinflammatory drug in serum albumins of different species. Organic Chemistry Frontiers. 6(1):99-109. https://doi.org/10.1039/c8qo01045eS9910961Limones-Herrero, D., Pérez-Ruiz, R., Lence, E., González-Bello, C., Miranda, M. A., & Jiménez, M. C. (2017). Mapping a protein recognition centre with chiral photoactive ligands. An integrated approach combining photophysics, reactivity, proteomics and molecular dynamics simulation studies. Chemical Science, 8(4), 2621-2628. doi:10.1039/c6sc04900aO’Brien, W. M., & Bagby, G. F. (1987). Carprofen: A New Nonsteroidal Antiinflammatory Drug Pharmacology, Clinical Efficacy and Adverse Effects. Pharmacotherapy: The Journal of Human Pharmacology and Drug Therapy, 7(1), 16-24. doi:10.1002/j.1875-9114.1987.tb03500.xCurry, S. L., Cogar, S. M., & Cook, J. L. (2005). Nonsteroidal Antiinflammatory Drugs: A Review. Journal of the American Animal Hospital Association, 41(5), 298-309. doi:10.5326/0410298LEES, P., LANDONI, M. F., Giraudel, J., & TOUTAIN, P. L. (2004). 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    Searches at HERA for Squarks in R-Parity Violating Supersymmetry

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    A search for squarks in R-parity violating supersymmetry is performed in e^+p collisions at HERA at a centre of mass energy of 300 GeV, using H1 data corresponding to an integrated luminosity of 37 pb^(-1). The direct production of single squarks of any generation in positron-quark fusion via a Yukawa coupling lambda' is considered, taking into account R-parity violating and conserving decays of the squarks. No significant deviation from the Standard Model expectation is found. The results are interpreted in terms of constraints within the Minimal Supersymmetric Standard Model (MSSM), the constrained MSSM and the minimal Supergravity model, and their sensitivity to the model parameters is studied in detail. For a Yukawa coupling of electromagnetic strength, squark masses below 260 GeV are excluded at 95% confidence level in a large part of the parameter space. For a 100 times smaller coupling strength masses up to 182 GeV are excluded.Comment: 32 pages, 14 figures, 3 table

    Deep-Inelastic Inclusive ep Scattering at Low x and a Determination of alpha_s

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    A precise measurement of the inclusive deep-inelastic e^+p scattering cross section is reported in the kinematic range 1.5<= Q^2 <=150 GeV^2 and 3*10^(-5)<= x <=0.2. The data were recorded with the H1 detector at HERA in 1996 and 1997, and correspond to an integrated luminosity of 20 pb^(-1). The double differential cross section, from which the proton structure function F_2(x,Q^2) and the longitudinal structure function F_L(x,Q^2) are extracted, is measured with typically 1% statistical and 3% systematic uncertainties. The measured partial derivative (dF_2(x,Q^2)/dln Q^2)_x is observed to rise continuously towards small x for fixed Q^2. The cross section data are combined with published H1 measurements at high Q^2 for a next-to-leading order DGLAP QCD analysis.The H1 data determine the gluon momentum distribution in the range 3*10^(-4)<= x <=0.1 to within an experimental accuracy of about 3% for Q^2 =20 GeV^2. A fit of the H1 measurements and the mu p data of the BCDMS collaboration allows the strong coupling constant alpha_s and the gluon distribution to be simultaneously determined. A value of alpha _s(M_Z^2)=0.1150+-0.0017 (exp) +0.0009-0.0005 (model) is obtained in NLO, with an additional theoretical uncertainty of about +-0.005, mainly due to the uncertainty of the renormalisation scale.Comment: 68 pages, 24 figures and 18 table

    Measurements of Transverse Energy Flow in Deep-Inelastic Scattering at HERA

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    Measurements of transverse energy flow are presented for neutral current deep-inelastic scattering events produced in positron-proton collisions at HERA. The kinematic range covers squared momentum transfers Q^2 from 3.2 to 2,200 GeV^2, the Bjorken scaling variable x from 8.10^{-5} to 0.11 and the hadronic mass W from 66 to 233 GeV. The transverse energy flow is measured in the hadronic centre of mass frame and is studied as a function of Q^2, x, W and pseudorapidity. A comparison is made with QCD based models. The behaviour of the mean transverse energy in the central pseudorapidity region and an interval corresponding to the photon fragmentation region are analysed as a function of Q^2 and W.Comment: 26 pages, 8 figures, submitted to Eur. Phys.

    Phosphorylation of Ubc9 by Cdk1 Enhances SUMOylation Activity

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    Increasing evidence has pointed to an important role of SUMOylation in cell cycle regulation, especially for M phase. In the current studies, we have obtained evidence through in vitro studies that the master M phase regulator CDK1/cyclin B kinase phosphorylates the SUMOylation machinery component Ubc9, leading to its enhanced SUMOylation activity. First, we show that CDK1/cyclin B, but not many other cell cycle kinases such as CDK2/cyclin E, ERK1, ERK2, PKA and JNK2/SAPK1, specifically enhances SUMOylation activity. Second, CDK1/cyclin B phosphorylates the SUMOylation machinery component Ubc9, but not SAE1/SAE2 or SUMO1. Third, CDK1/cyclin B-phosphorylated Ubc9 exhibits increased SUMOylation activity and elevated accumulation of the Ubc9-SUMO1 thioester conjugate. Fourth, CDK1/cyclin B enhances SUMOylation activity through phosphorylation of Ubc9 at serine 71. These studies demonstrate for the first time that the cell cycle-specific kinase CDK1/cyclin B phosphorylates a SUMOylation machinery component to increase its overall SUMOylation activity, suggesting that SUMOylation is part of the cell cycle program orchestrated by CDK1 through Ubc9

    Measurement and QCD Analysis of Neutral and Charged Current Cross Sections at HERA

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    Inelastic photoproduction of J/Psi mesons at HERA

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    An analysis of inelastic photoproduction of J/Psi mesons is presented using data collected at the ep collider HERA corresponding to an integrated luminosity of above 80pb-1. Differential and double differential cross sections are measured in a wide kinematic region: 6
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