1,125 research outputs found

    Five-dimensional generalized f(R)f(R) gravity with curvature-matter coupling

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    The generalized f(R)f(R) gravity with curvature-matter coupling in five-dimensional (5D) spacetime can be established by assuming a hypersurface-orthogonal spacelike Killing vector field of 5D spacetime, and it can be reduced to the 4D formulism of FRW universe. This theory is quite general and can give the corresponding results to the Einstein gravity, f(R)f(R) gravity with both no-coupling and non-minimal coupling in 5D spacetime as special cases, that is, we would give the some new results besides previous ones given by Ref.\cite{60}. Furthermore, in order to get some insight into the effects of this theory on the 4D spacetime, by considering a specific type of models with f1(R)=f2(R)=αRmf_{1}(R)=f_{2}(R)=\alpha R^{m} and B(Lm)=Lm=ρB(L_{m})=L_{m}=-\rho, we not only discuss the constraints on the model parameters mm, nn, but also illustrate the evolutionary trajectories of the scale factor a(t)a(t), the deceleration parameter q(t)q(t) and the scalar field ϵ(t)\epsilon(t), ϕ(t)\phi(t) in the reduced 4D spacetime. The research results show that this type of f(R)f(R) gravity models given by us could explain the current accelerated expansion of our universe without introducing dark energy.Comment: arXiv admin note: text overlap with arXiv:0912.4581, arXiv:gr-qc/0411066 by other author

    (S)-(+)-4-(Oxiran-2-ylmeth­oxy)-9H-carbazole

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    In the title compound, C15H13NO2, all atoms of the carbazole group are coplanar (r.m.s. deviation = 0.005 Å), and the dihedral angle between this plane and C—O—C plane of oxane group is 57.1 (4)°. The crystal packing is stabilized by an N—H⋯O hydrogen bond, resulting in infinite supra­molecular chains along [001]

    Metformin improves the angiogenic functions of endothelial progenitor cells via activating AMPK/eNOS pathway in diabetic mice

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    Additional file 3: Figure S3. BM-EPC functions under the osmotic pressure equal to that of high glucose (HG). Compared with the normal glucose (NG), BM-EPCs treated by mannitol to make equal osmotic pressure with HG showed no significant changes in tube formation and migration.**P < 0.01, vs NG; # P < 0.05 vs HG. Values are mean ± SEM (n = 5 per group)
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