5,987 research outputs found

    Total synthesis and biological evaluation of the tetramic acid based natural product harzianic acid and its stereoisomers

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    Financial support for this project was provided by Cancer Research UK (Grant No. C21383/A6950)The bioactive natural product harzianic acid was prepared for the first time in just six steps (longest linear sequence) with an overall yield of 22%. The identification of conditions to telescope amide bond formation and a Lacey-Dieckmann reaction into one pot proved important. The three stereoisomers of harzianic acid were also prepared, providing material for comparison of their biological activity. While all of the isomers promoted root growth, improved antifungal activity was unexpectedly associated with isomers in the enantiomeric series opposite that of harzianic acid.Publisher PDFPeer reviewe

    Expression profiling of snoRNAs in normal hematopoiesis and AML

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    Key Points A subset of snoRNAs is expressed in a developmental- and lineage-specific manner during human hematopoiesis. Neither host gene expression nor alternative splicing accounted for the observed differential expression of snoRNAs in a subset of AML.</jats:p

    TPL-2 restricts Ccl24-dependent immunity to Heligmosomoides polygyrus

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    Funding: This work was supported by the Francis Crick Institute which receives its core funding from Cancer Research UK (FC001220), the UK Medical Research Council (FC001220), and the Wellcome Trust (FC001200). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Acknowledgments We are indebted to The Francis Crick Institute Flow Cytometry facility, and in particular Bhavik Patel, Graham Preece, Wayne Turnbull and Phil Hobson. We would also like to thank The Francis Crick Institute Procedural Service Section for production of GA lines and Biological Services, especially Trisha Norton, Keith Williams and Adebambo Adekoya for animal husbandry and technical support; to Riccardo Guidi for constructive discussions and technical assistance. We would like to thank Gitta Stockinger and AhR Immunity Laboratory for providing technical support and reagents throughout this study. We also thank Richard Rance and the Wellcome Trust Sanger Institute’s 454 pyrosequencing team for generating 16S rRNA gene data.Peer reviewedPublisher PD

    The reaction 2H(p,pp)n in three kinematical configurations at E_p = 16 MeV

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    We measured the cross sections of the 2^2H(p,pp)n breakup reaction at Ep_p=16 MeV in three kinematical configurations: the np final-state interaction (FSI), the co-planar star (CST), and an intermediate-star (IST) geometry. The cross sections are compared with theoretical predictions based on the CD Bonn potential alone and combined with the updated 2π\pi-exchange Tucson-Melbourne three-nucleon force (TM99'), calculated without inclusion of the Coulomb interaction. The resulting excellent agreement between data and pure CD Bonn predictions in the FSI testifies to the smallness of three-nucleon force (3NF) effects as well as the insignificance of the Coulomb force for this particular configuration and energy. The CST also agrees well whereas the IST results show small deviations between measurements and theory seen before in the pd breakup space-star geometries which point to possible Coulomb effects. An additional comparison with EFT predictions (without 3NF) up to order N3^3LO shows excellent agreement in the FSI case and a rather similar agreement as for CD Bonn in the CST and IST situations.Comment: 20 pages, 11 figure

    Generalized Morse Potential: Symmetry and Satellite Potentials

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    We study in detail the bound state spectrum of the generalized Morse potential~(GMP), which was proposed by Deng and Fan as a potential function for diatomic molecules. By connecting the corresponding Schr\"odinger equation with the Laplace equation on the hyperboloid and the Schr\"odinger equation for the P\"oschl-Teller potential, we explain the exact solvability of the problem by an so(2,2)so(2,2) symmetry algebra, and obtain an explicit realization of the latter as su(1,1)⊕su(1,1)su(1,1) \oplus su(1,1). We prove that some of the so(2,2)so(2,2) generators connect among themselves wave functions belonging to different GMP's (called satellite potentials). The conserved quantity is some combination of the potential parameters instead of the level energy, as for potential algebras. Hence, so(2,2)so(2,2) belongs to a new class of symmetry algebras. We also stress the usefulness of our algebraic results for simplifying the calculation of Frank-Condon factors for electromagnetic transitions between rovibrational levels based on different electronic states.Comment: 23 pages, LaTeX, 2 figures (on request). one LaTeX problem settle

    Connection Between Type A and E Factorizations and Construction of Satellite Algebras

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    Recently, we introduced a new class of symmetry algebras, called satellite algebras, which connect with one another wavefunctions belonging to different potentials of a given family, and corresponding to different energy eigenvalues. Here the role of the factorization method in the construction of such algebras is investigated. A general procedure for determining an so(2,2) or so(2,1) satellite algebra for all the Hamiltonians that admit a type E factorization is proposed. Such a procedure is based on the known relationship between type A and E factorizations, combined with an algebraization similar to that used in the construction of potential algebras. It is illustrated with the examples of the generalized Morse potential, the Rosen-Morse potential, the Kepler problem in a space of constant negative curvature, and, in each case, the conserved quantity is identified. It should be stressed that the method proposed is fairly general since the other factorization types may be considered as limiting cases of type A or E factorizations.Comment: 20 pages, LaTeX, no figure, to be published in J. Phys.
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