Tohoku University

About: Tohoku University is a education organization based out in Sendai, Japan. It is known for research contribution in the topics: Magnetization & Alloy. The organization has 72116 authors who have published 170791 publications receiving 3941714 citations. The organization is also known as: Tōhoku daigaku.

Observation of the DsJ(2317) and DsJ(2457) in B Decays

Abstract: We report the first observation of the B-->(D) over barD(sJ)(2317) and B-->(D) over barD(sJ)(2457) decays based on 123.8x10(6) B (B) over bar events collected with the Belle detector at KEKB. We observe the D-sJ(2317) decay to D(s)pi(0) and the D-sJ(2457) decay to the D(s)(*)pi(0) and D(s)gamma final states. We also set 90% C.L. upper limits for the decays D-sJ(2317)-->D-s*gamma, D-sJ(2457)-->D-s*gamma, D-sJ(2457)-->D(s)pi(0), and D-sJ(2457)-->D(s)pi(+)pi(-).

Passive Spiral Formation from Halo Gas Starvation: Gradual Transformation into S0s

Abstract: Recent spectroscopic and high-resolution Hubble Space Telescope (HST) imaging observations have revealed significant numbers of "passive" spiral galaxies in distant clusters, with all the morphological hallmarks of a spiral galaxy (in particular, spiral arm structure), but with weak or absent star formation. Exactly how such spiral galaxies formed and whether they are the progenitors of present-day S0 galaxies is unclear. Based on analytic arguments and numerical simulations of the hydrodynamical evolution of a spiral galaxy's halo gas (which is a likely candidate for the source of gas replenishment for star formation in spirals), we show that the origin of passive spirals may well be associated with halo gas stripping. Such stripping results mainly from the hydrodynamical interaction between the halo gas and the hot intracluster gas. Our numerical simulations demonstrate that even if a spiral orbits a cluster with a pericenter distance ~3 times larger than the cluster core radius, ~80% of the halo gas is stripped within a few Gyr and, accordingly, cannot be accreted by the spiral. Furthermore, our study demonstrates that this dramatic decline in the gaseous infall rate leads to a steady increase in the Q parameter for the disk, with the spiral arm structure, although persisting, becoming less pronounced as the star formation rate gradually decreases. These results suggest that passive spirals formed in this way gradually evolve into red cluster S0s.

Strong attenuation of ischemic and postischemic brain edema in rats by a novel free radical scavenger.

Abstract: Regional changes in the amount of free fatty acids, polyphosphoinositides, and water content in the cerebral cortex were examined using a middle cerebral artery occlusion model of rats. The amount of various free fatty acids increased as polyphosphoinositides decreased during 3 and 6 hours of ischemia in the occluded middle cerebral artery territory. After 3 hours of reperfusion following 3 hours of ischemia, free fatty acids partially recovered while polyphosphoinositides did not. Water content increased significantly after 3 and 6 hours of ischemia, and a further increase was found after 3 hours of reperfusion following 3 hours of ischemia. The change of polyenoic fatty acids in this occluded middle cerebral artery territory was much smaller than that in the case of decapitation ischemia, although the amounts of polyphosphoinositides and monoenoic and saturated fatty acids showed almost identical changes in both cases, probably because polyenoic fatty acids may be washed out and/or peroxidatively consumed in the middle cerebral artery occlusion model due to its residual blood flow. Changes in the area surrounding the occluded middle cerebral artery territory were similar to the above results, although less dramatic. However, there was no change in free fatty acids, polyphosphoinositides, and water content in the contralateral cortex. A novel free radical scavenger (MCI-186), which prevents both nonenzymatic peroxidation and lipoxygenase activity in vitro, markedly attenuated the ischemic and postischemic brain swelling. These results suggest that free radical mechanisms may be involved in ischemic and postischemic brain edema.