1,169 research outputs found
The Bowman-Bradley theorem for multiple zeta-star values
The Bowman-Bradley theorem asserts that the multiple zeta values at the
sequences obtained by inserting a fixed number of twos between 3,1,...,3,1 add
up to a rational multiple of a power of pi. We establish its counterpart for
multiple zeta-star values by showing an identity in a non-commutative
polynomial algebra introduced by Hoffman.Comment: 17 page
Extended Soliton Solutions in an Effective Action for SU(2) Yang-Mills Theory
The Skyrme-Faddeev-Niemi (SFN) model which is an O(3) model in three
dimensional space up to fourth-order in the first derivative is regarded as a
low-energy effective theory of SU(2) Yang-Mills theory. One can show from the
Wilsonian renormalization group argument that the effective action of
Yang-Mills theory recovers the SFN in the infrared region. However, the theory
contains an additional fourth-order term which destabilizes the soliton
solution. We apply the perturbative treatment to the second derivative term in
order to exclude (or reduce) the ill behavior of the original action and show
that the SFN model with the second derivative term possesses soliton solutions.Comment: Published in SIGMA (Symmetry, Integrability and Geometry: Methods and
Applications) at http://www.emis.de/journals/SIGMA
Small GTP-binding protein Rho-mediated signaling promotes proliferation of rheumatoid synovial fibroblasts
Rho is a major small GTP-binding protein that is involved in the regulation of various cell functions, including proliferation and cell migration, through activation of multiple signaling molecules in various types of cells. We studied its roles in synovial fibroblasts (SFs) in patients with rheumatoid arthritis (RA) and clarified its relevance to RA synovitis, with the following results. 1)We found that the thrombin receptor was overexpressed on RA synovial fibroblasts (RA SFs) and that thrombin induced a marked proliferation and progression of the cell cycle to the S phase in these cells. 2)We also found that thrombin efficiently activated Rho. 3)Rho activation and proliferation and the progression of the cell cycle to the S phase were completely blocked by p115RGS (an N-terminal regulator of the G-protein signaling domain of p115RhoGEF) and by the C-terminal fragments of Gα13 (an inhibitor of the interaction of receptors with G13). 4)Thrombin induced the secretion of IL-6 by RA SFs, but this action was blocked by p115RGS or Gα13. Our findings show that the actions of thrombin on the proliferation of RA SFs, cell-cycle progression to the S phase, and IL-6 secretion were mainly mediated by the G13 and RhoGEF pathways. These results suggest that p115RGS and Gα13 could be potent inhibitors of such functions. A rational design of future therapeutic strategies for RA synovitis could perhaps include the exploitation of the Rho pathway to directly reduce the growth of synovial cells
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