Hokkaido University

About: Hokkaido University is a education organization based out in Sapporo, Hokkaidô, Japan. It is known for research contribution in the topics: Catalysis & Population. The organization has 53925 authors who have published 115403 publications receiving 2651647 citations. The organization is also known as: Hokudai & Hokkaidō daigaku.

Heterogeneous multi-core fibers: proposal and design principle

Abstract: A new type of optical fiber called heterogeneous multi-core fiber (heterogeneous MCF) is proposed towards future large-capacity optical-transport networks and the design principle is described. In the heterogeneous MCF, not only identical but also non-identical cores, which are single-mode in isolation of each other, are arranged so that cross-talk between any pair of cores becomes sufficiently small. As the maximum power transferred between non-identical cores goes down drastically, cores are more closely packed in definite space, compared to a conventional, homogeneous multi-core fiber (homogeneous MCF) composed of only identical cores.

Effects of Astaxanthin on Lipopolysaccharide-Induced Inflammation In Vitro and In Vivo

Abstract: PURPOSE. Astaxanthin (AST) is a carotenoid that is found in marine animals and vegetables. Several previous studies have demonstrated that AST exhibits a wide variety of biological activities including antioxidant, antitumor, and anti-Helicobacter pylori effects. In this study, attention was focused on the antioxidant effect of AST. The object of the present study was to investigate the efficacy of AST in endotoxin-induced uveitis (EIU) in rats. In addition, the effect of AST on endotoxininduced nitric oxide (NO), prostaglandin E2 (PGE2), and tumor necrosis factor (TNF)- production in a mouse macrophage cell line (RAW 264.7) was studied in vitro. METHODS. EIU was induced in male Lewis rats by a footpad injection of lipopolysaccharide (LPS). AST or prednisolone was administered intravenously at 30 minutes before, at the same time as, or at 30 minutes after LPS treatment. The number of infiltrating cells and protein concentration in the aqueous humor collected at 24 hours after LPS treatment was determined. RAW 264.7 cells were pretreated with various concentrations of AST for 24 hours and subsequently stimulated with 10 g/mL of LPS for 24 hours. The levels of PGE2, TNF-, and NO production were determined in vivo and in vitro. RESULTS. AST suppressed the development of EIU in a dosedependent fashion. The anti-inflammatory effect of 100 mg/kg AST was as strong as that of 10 mg/kg prednisolone. AST also decreased production of NO, activity of inducible nitric oxide synthase (NOS), and production of PGE2 and TNF- in RAW264.7 cells in vitro in a dose-dependent manner. CONCLUSIONS. This study suggests that AST has a dose-dependent ocular anti-inflammatory effect, by the suppression of NO, PGE2, and TNF- production, through directly blocking NOS enzyme activity. (Invest Ophthalmol Vis Sci. 2003;44:

Indoleamine 2,3 dioxygenase and quinolinic acid Immunoreactivity in Alzheimer's disease hippocampus

Abstract: The present immunohistochemical study provides evidence that the kynurenine pathway is up-regulated in Alzheimer's disease (AD) brain, leading to increases in the excitotoxin quinolinic acid (QUIN). We show that the regulatory enzyme of the pathway leading to QUIN synthesis, indoleamine 2,3 dioxygenase (IDO) is abundant in AD compared with controls. In AD hippocampus, both IDO- and QUIN-immunoreactivity (-IR) was detected in cortical microglia, astrocytes and neurones, with microglial and astrocytic expression of IDO and QUIN highest in the perimeter of senile plaques. QUIN-IR was present in granular deposits within the neuronal soma of AD cortex and was also seen uniformly labelling neurofibrillary tangles. Our data imply that QUIN may be involved in the complex and multifactorial cascade leading to neuro-degeneration in AD. These results may open a new therapeutic door for AD patients.

Discrimination and Clustering for Multivariate Time Series

Abstract: Minimum discrimination information provides a useful generalization of likelihood methodology for classification and clustering of multivariate time series. Discrimination between different classes of multivariate time series that can be characterized by differing covariance or spectral structures is of importance in applications occurring in the analysis of geophysical and medical time series data. For discrimination between such multivariate series, Kullback-Leibler discrimination information and the Chernoff information measure are developed for the multivariate non-Gaussian case. Asymptotic error rates and limiting distributions are given for a generalized spectral disparity measure that includes the foregoing criteria as special cases. Applications to problems of clustering and classifying earthquakes and mining explosions are given.