Osaka University

About: Osaka University is a education organization based out in Osaka, Japan. It is known for research contribution in the topics: Laser & Population. The organization has 83778 authors who have published 185669 publications receiving 5158122 citations. The organization is also known as: Ōsaka daigaku.

Roles of STAT3 in mediating the cell growth, differentiation and survival signals relayed through the IL-6 family of cytokine receptors.

Abstract: Members of the IL-6 cytokine family are involved in a variety of biological responses, including the immune response, inflammation, hematopoiesis, and oncogenesis by regulating cell growth, survival, and differentiation. These cytokines use gp130 as a common receptor subunit. The binding of ligand to gp130 activates the JAK/STAT signal transduction pathway, where STAT3 plays a central role in transmitting the signals from the membrane to the nucleus. STAT3 is essential for gp130-mediated cell survival and G1 to S cell-cycle-transition signals. Both c-myc and pim have been identified as target genes of STAT3 and together can compensate for STAT3 in cell survival and cell-cycle transition. STAT3 is also required for gp130-mediated maintenance of the pluripotential state of proliferating embryonic stem cells and for the gp130-induced macrophage differentiation of M1 cells. Furthermore, STAT3 regulates cell movement, such as leukocyte, epidermal cell, and keratinocyte migration. STAT3 also appears to regulate B cell differentiation into antibody-forming plasma cells. Since the IL-6/gp130/STAT3 signaling pathway is involved in both B cell growth and differentiation into plasma cells it is likely to play a central role in the generation of plasma cell neoplasias.

A new feedback method for dynamic control of manipulators

Abstract: Department of Mechanical Engineering, Faculty of Engineering SCience, Osaka University, Toyonaka, Osaka, 560 Japan A new approach to the dynamic control of manipulators is developed from the viewpoint of mechanics. It is /irst shown that a linear feedback of generalized coordinates and their derivatives are effective for motion control in the large. Next, we propose a method for task-oriented coordinate control which can be easily implemented by a micro-computer and is suited to sensor feedback control. The proposed method is applicable even when holonomic constraints are added to the system. Effectiveness of the proposed method is verified by computer simulation.

A General Analytic Formula for the Spectral Index of the Density Perturbations Produced during Inflation.

Abstract: During inflation'> vacuum fluctuations on scales less than the Hubble radius in scalar fields with effective masses much less than the Hubble parameter**> are magnified into classical perturbations in the scalar fields on scales larger than the Hubble radius. These classical perturbations in the scalar fields can then change the number of e-folds of expansion and so lead to classical curvature/density perturba­ tions after inflation. These density perturbations are thought to be responsible for the formation of galaxies and the large scale structure of the observable Universe as well as, in combination with the gravitational waves produced during inflation, for the anisotropies in the cosmic microwave background. The standard calculation 7 H 1 > of the spectrum of density perturbations produced during inflation assumes that there is only one real dynamical degree of freedom during inflation. Although this is the case in most of the models of inflation con­ structed up to now, it is by assumption rather than prediction. When one tries to construct models of inflation 3 >,s>. 12 > that might arise naturally in realistic models of particle physics, such as the low energy effective supergravity theories derived from superstrings, one often gets more than one dynamical degree of freedom during inflation. The standard calculation is then generally not applicable. In this paper we derive general analytic formulae for the spectrum and spectral index of the density perturbations produced during inflation. This work is based on earlier work by Starobinsky. 13 > See also Ref. 14). While this work was in slow preparation three other related papers