Observation of Cabibbo suppressed B --> D(*)K- decays at Belle

We report observations of the Cabibbo suppressed decays B-->D((*))K- using a 10.4 fb(-1) data sample accumulated at the Upsilon(4S) resonance with the Belle detector at the KEKB e(+)e(-) storage ring. We find that the ratios of Cabibbo suppressed to Cabibbo favored branching fractions are B(B--->D0K-)/B(B--->D0pi(-)) = 0.079+/-0.009+/-0.006, B(B(0)-->D+K-)/B(B(0)-->D+pi(-)) = 0.068+/-0.015+/-0.007, B(B--->D(*0)K-)/B(B--->D(*0)pi(-)) = 0.078+/-0.019+/-0.009, and B(B(0)-->D(*+)K-)/B(B(0)-->D(*+)pi(-)) = 0.074+/-0.015+/-0.006. These are the first observations of the B-->D+K-, D(*0)K-, and D(*+)K- decay processes.     

Brain regional uptake of radioactive Sc, Mn, Zn, Se, Rb and Zr tracers into normal mice during aging

Radioactive multitracer technique was applied to study the brain regional uptake of trace elements by the normal mice during aging. The brain regional radioactivities of ⁴⁶Sc, ⁵⁴Mn, ⁶⁵Zn, ⁷⁵Se, ⁸³Rb and ⁸⁸Zr were measured 48 hours after intraperitoneal injection of a solution in normal mice aged 6 to 52 weeks to evaluate the brain regional (corpus striatum, cerebellum, cerebral cortex, hippocampus, and pons and medulla) uptakes. The radioactive distributions of ⁴⁶Sc, ⁵⁴Mn and ⁸⁸Zr tracers were variable and region-specific in the brain, while those of ⁶⁵Zn, ⁷⁵Se and ⁸³Rb tracers were comparable among all regions of interest. The brain regional uptakes of all tracers slightly increased with age from 10 to 28 weeks, and then remained constant during aging after 28 weeks. These uptake variations may be involved in the functional degenerative process of the blood-brain barrier during aging.     

An extrinsic decomposition theorem and a slant tube theorem for a curvature netted hypersurface

In this paper, we treat hypersurfaces in a Euclidean space the number of whose distinct principal curvatures is constant almost everywhere. We call such a hypersurface satisfying certain additional condition a curvature netted hypersurface. First we shall define the notions of a twisted (or warped) sum immersion, a slant focal map and a slant tube. We shall investigate, in what case, a complete curvature netted hypersurface is immersed by a warped sum immersion or becomes a slant tube of the image of a slant focal map.     

New synthesis of multi-substituted α-chlorocyclobutanones from 1-chloro-3-cyanoalkyl p-tolyl sulfoxides by 4-Exo-Dig nucleophilic ring closure of magnesium carbenoids to nitrile group as the key reaction

1-Chloro-3-cyanoalkyl p-tolyl sulfoxides were easily prepared from 1-chlorovinyl p-tolyl sulfoxides, which were synthesized from carbonyl compounds and chloromethyl p-tolyl sulfoxide, with lithium α-cyano carbanion of acetonitrile derivatives in good yields. Treatment of these sulfoxides with i-PrMgCl resulted in the formation of multi-substituted α-chlorocyclobutanones in good to high yields via the 4-Exo-Dig nucleophilic ring closure of the generated magnesium carbenoid intermediates to the nitrile group. This procedure provides a new and good way for the synthesis of multi-substituted α-chlorocyclobutanones from carbonyl compounds and substituted acetonitriles with formation of three carbon–carbon bonds in relatively short steps.