73 research outputs found
Observation of a J^PC = 1-+ exotic resonance in diffractive dissociation of 190 GeV/c pi- into pi- pi- pi+
The COMPASS experiment at the CERN SPS has studied the diffractive
dissociation of negative pions into the pi- pi- pi+ final state using a 190
GeV/c pion beam hitting a lead target. A partial wave analysis has been
performed on a sample of 420000 events taken at values of the squared
4-momentum transfer t' between 0.1 and 1 GeV^2/c^2. The well-known resonances
a1(1260), a2(1320), and pi2(1670) are clearly observed. In addition, the data
show a significant natural parity exchange production of a resonance with
spin-exotic quantum numbers J^PC = 1-+ at 1.66 GeV/c^2 decaying to rho pi. The
resonant nature of this wave is evident from the mass-dependent phase
differences to the J^PC = 2-+ and 1++ waves. From a mass-dependent fit a
resonance mass of 1660 +- 10+0-64 MeV/c^2 and a width of 269+-21+42-64 MeV/c^2
is deduced.Comment: 7 page, 3 figures; version 2 gives some more details, data unchanged;
version 3 updated authors, text shortened, data unchange
SSeCKS/Gravin/AKAP12 attenuates expression of proliferative and angiogenic genes during suppression of v-Src-induced oncogenesis
BACKGROUND: SSeCKS is a major protein kinase C substrate with kinase scaffolding and metastasis-suppressor activity whose expression is severely downregulated in Src- and Ras-transformed fibroblast and epithelial cells and in human prostate, breast, and gastric cancers. We previously used NIH3T3 cells with tetracycline-regulated SSeCKS expression plus a temperature-sensitive v-Src allele to show that SSeCKS re-expression inhibited parameters of v-Src-induced oncogenic growth without attenuating in vivo Src kinase activity. METHODS: We use cDNA microarrays and semi-quantitative RT-PCR analysis to identify changes in gene expression correlating with i) SSeCKS expression in the absence of v-Src activity, ii) activation of v-Src activity alone, and iii) SSeCKS re-expression in the presence of active v-Src. RESULTS: SSeCKS re-expression resulted in the attenuation of critical Src-induced proliferative and pro-angiogenic gene expression including Afp, Hif-1α, Cdc20a and Pdgfr-β, and conversely, SSeCKS induced several cell cycle regulatory genes such as Ptpn11, Gadd45a, Ptplad1, Cdkn2d (p19), and Rbbp7. CONCLUSION: Our data provide further evidence that SSeCKS can suppress Src-induced oncogenesis by modulating gene expression downstream of Src kinase activity
A Chiral Magnetic Effect from AdS/CFT with Flavor
For (3+1)-dimensional fermions, a net axial charge and external magnetic
field can lead to a current parallel to the magnetic field. This is the chiral
magnetic effect. We use gauge-gravity duality to study the chiral magnetic
effect in large-Nc, strongly-coupled N=4 supersymmetric SU(Nc) Yang-Mills
theory coupled to a number Nf << Nc of N=2 hypermultiplets in the Nc
representation of SU(Nc), i.e. flavor fields. Specifically, we introduce an
external magnetic field and a time-dependent phase for the mass of the flavor
fields, which is equivalent to an axial chemical potential for the flavor
fermions, and we compute holographically the resulting chiral magnetic current.
For massless flavors we find that the current takes the value determined by the
axial anomaly. For massive flavors the current appears only in the presence of
a condensate of pseudo-scalar mesons, and has a smaller value than for massless
flavors, dropping to zero for sufficiently large mass or magnetic field. The
axial symmetry in our system is part of the R-symmetry, and the states we study
involve a net flow of axial charge to the adjoint sector from an external
source coupled to the flavors. We compute the time rate of change of axial
charge and of energy both in field theory and from holography, with perfect
agreement. In contrast to previous holographic models of the chiral magnetic
effect, in our system the vector current is conserved and gauge-invariant
without any special counterterms.Comment: 54 pages, 18 eps files in 6 figure
Crystal structure of Sr(AsUO6)2·8H2O
The crystal structure of the compound Sr(AsUO6)2·8H2O is determined by X-ray diffraction analysis (monoclinic system, sp. gr. Pc, unit-cell parameters a = 7.154(1) Å, b = 7.101(1) Å, c = 18.901(7) Å, beta = 92.67(2)°, Z = 2). The structure is built by (001)-parallel [AsUO6]- layers formed by flattened square UO6 bipyramids and AsO4 tetrahedra. The neighboring layers are connected via SrO8 square antiprisms. The cavities of the polyhedral framework thus formed are occupied by H2O molecules. The displacements of the anion complexes by a half-translation with respect to one another along only one lattice period is a characteristic feature of this polymorphous modification of the uran-mica group
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