250 research outputs found
Improved gauge action on an anisotropic lattice II - Anisotropy parameter in the medium coupling region -
The quantum correction of the anisotropy parameter, , is calculated for
and 3 in the region where numerical simulations such as hadron
spectroscopy are currently carried out, for the improved actions composed of
plaquette and rectangular 6-link loops. The dependences of for
the renormalization group improved actions are quite different from those of
the standard and Symanzik actions. In Iwasaki and DBW2 actions, stays
almost constant in a wide range of , which also differs from the
one-loop perturbative result, while in the case of Symanzik action, it
increases as decreases, which is qualitatively similar to the
perturbative result, but the slope is steeper. In the calculation of the
parameter close to and in the confined phase, we have applied the link
integration method to suppress the fluctuation of the gauge fields. Some
technical details are summarized.Comment: 21 pages, 10 figure
Transport Coefficients of Gluon Plasma
Transport coefficients of gluon plasma are calculated for a SU(3) pure gauge
model by lattice QCD simulations on and
lattices. Simulations are carried out at a slightly above the deconfinement
transition temperature , where a new state of matter is currently being
pursued in RHIC experiments. Our results show that the ratio of the shear
viscosity to the entropy is less than one and the bulk viscosity is consistent
with zero in the region, .Comment: 10 pages, Late
神経誘導因子Netrin-1は軟骨形成や骨形成においてBMPまたはNogginにより調節される
This is the first report describing neurogenic factor of Netrin-1 related to chondrogenesis or osteogenesis in a human cells. Netrin is a morphogenetic factor that induces a growth cone of an axial filament of the nervous system. However, the roles of Netrin in chondrogenesis or osteogenesis are not yet understood. We analyzed the relationship between Netrin and bone morphogenetic protein-2 (BMP-2) in chondrogenesis or osteogenesis, using a human chondrocyte-like cell line (USAC), which also retains multi-potency to differentiate into osteoblasts and adipocytes. Netrin-1 mRNA was decreased in USAC cells, though the expression was increased during osteogenic differentiation at the stage when osteocalcin mRNA were increased by BMP-2. Furthermore, inhibition of Netrin-1 gene increased Cbfa1 mRNA expression, and decreased Sox9 mRNA expression. We also found that Netrin-1was strongly expressed in immature chondrocytes of cartilage-like tissues that were formed in an exo vivo experiment with diffusion chambers. The se findings indicate that Netrin-1 and BMP-2 regulates in the stage dependent process of mesenchymal cell differentiation to chondrocytes or osteoblasts.骨芽細胞または脂肪細胞への分化多能を保持するヒト軟骨細胞様細胞系(USAC)を用い、軟骨形成または骨形成におけるNetrinと骨形成蛋白質-2(BMP-2)との関係を調べた。Netrin-1 mRNAはUSAC細胞中では減少するが、オステオカルシンmRNA濃度がBMPによって上昇する際の骨芽細胞分化時にNetrin-1 mRNAの発現が増加した。Netrin-1遺伝子を阻害すると、Cbfal mRNA発現は増加しSox9 mRNA発現は減少した。またNetrin-1は軟骨様組織の未成熟軟骨細胞において強く発現した。Netrin-1とBMP-2が、間葉細胞の軟骨細胞または骨芽細胞へ分化プロセスを制御すると考えた
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