Tohoku University

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

On the differential geometry of tangent bundles of riemannian manifolds ii

Abstract: H.Poincare used the tangent sphere-bundles of ovaloids in three dimensional Euclidean space, i.e. the phase spaces of the ovaloids, to prove the existence of certain closed geodesies on the ovaloids. He introduced a Riemannian metric on the tangent sphere-bundles and considered the geodesic flow on it. As the metric of tangent bundles of Riemannian manifolds seems to be important, we would like to study differential geometry of tangent bundles of Riemannian manifolds by introducing on it natural Riemannian metrics. In this papar we shall do it by restricting ourselves only to the tangent bundles T{M).

Evidence for an Oscillatory Signature in Atmospheric Neutrino Oscillations

Abstract: Muon neutrino disappearance probability as a function of neutrino flight length $L$ over neutrino energy $E$ was studied. A dip in the $L/E$ distribution was observed in the data, as predicted from the sinusoidal flavor transition probability of neutrino oscillation. The observed $L/E$ distribution constrained ${\ensuremath{ u}}_{\ensuremath{\mu}}\ensuremath{\leftrightarrow}{\ensuremath{ u}}_{\ensuremath{\tau}}$ neutrino oscillation parameters; $1.9\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}3}l\ensuremath{\Delta}{m}^{2}l3.0\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}3}\text{ }\text{ }{\mathrm{e}\mathrm{V}}^{2}$ and ${sin }^{2}2\ensuremath{\theta}g0.90$ at 90% confidence level.

Neuromyelitis optica: pathogenicity of patient immunoglobulin in vivo.

Abstract: Objective Severe inflammation and astrocyte loss with profound demyelination in spinal cord and optic nerves are typical pathological features of neuromyelitis optica (NMO). A diagnostic hallmark of this disease is the presence of serum autoantibodies against the water channel aquaporin-4 (AQP-4) on astrocytes. Methods We induced acute T-cell–mediated experimental autoimmune encephalomyelitis in Lewis rats and confronted the animals with an additional application of immunoglobulins from AQP-4 antibody–positive and –negative NMO patients, multiple sclerosis patients, and control subjects. Results The immunoglobulins from AQP-4 antibody–positive NMO patients are pathogenic. When they reach serum titers in experimental animals comparable with those seen in NMO patients, they augment clinical disease and induce lesions in the central nervous system that are similar in structure and distribution to those seen in NMO patients, consisting of AQP-4 and astrocyte loss, granulocytic infiltrates, T cells and activated macrophages/microglia cells, and an extensive immunoglobulin and complement deposition on astrocyte processes of the perivascular and superficial glia limitans. AQP-4 antibody containing NMO immunoglobulin injected into naive rats, young rats with leaky blood–brain barrier, or after transfer of a nonencephalitogenic T-cell line did not induce disease or neuropathological alterations in the central nervous system. Absorption of NMO immunoglobulins with AQP-4–transfected cells, but not with mock-transfected control cells, reduced the AQP-4 antibody titers and was associated with a reduction of astrocyte pathology after transfer. Interpretation Human anti–AQP-4 antibodies are not only important in the diagnosis of NMO but also augment disease and induce NMO-like lesions in animals with T-cell–mediated brain inflammation. Ann Neurol 2009;66:630–643