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Saitama, Japan

Saitama University is a Japanese national university located in a suburban area of Sakura-ku, Saitama City capital of Saitama Prefecture in Tokyo Metropolitan Area.The University has five faculties for undergraduate education -Liberal Arts, Education, Economics, Science, and Engineering- and four graduate schools -Cultural Science, Education, Economic Science, and Science and Engineering-, all offering programs leading to doctorates as well as master’s degrees. The total enrollment in the university is more than 8,500 with more than 500 overseas students pursuing undergraduate and postgraduate studies . Wikipedia.

Lumped parameter models with a so called "gyro-mass" element (GLPMs) have been proposed recently in response to a strong demand for efficiently and accurately representing frequency-dependent impedance functions of soil-foundation systems. Although GLPMs are considered to be powerful tools for practical applications in earthquake engineering, some problems remain. For instance, although GLPMs show fairly close agreement with the target impedance functions, the accuracy of the transfer functions and the time-histories of dynamic responses in structural systems comprising GLPMs have never been verified. Furthermore, no assessment has been performed on how much difference appears in the accuracy of dynamic responses obtained from GLPMs and those from conventional Kelvin-Voigt models comprising a spring and a dashpot arranged in parallel with various frequency-independent constants. Therefore, in this paper, these problems are examined using an example of 2×4 pile groups embedded in a layered soil medium, supporting a single-degree-of-freedom system subjected to ground motions. The results suggest that GLPMs are a new option for highly accurate computations in evaluating the dynamic response of structural systems comprising typical pile groups, rather than conventional Kelvin-Voigt models. © 2011 John Wiley & Sons, Ltd. Source

Maruyama Y.,Saitama University
International Journal of Cardiology | Year: 2012

Cardiovascular system changes with aging, and these changes are modified by arteriosclerosis-risk factors, i.e., hypertension and diabetes, as well as arterial-cardiac interactions. Regarding age-related changes in the cardiovascular system, Lakatta et al. reported morphological and functional changes that are specific to the cardiovascular aging and are distinct from arteriosclerotic changes. After then, various studies on the mechanism of aging of the cardiovascular system have been performed from the viewpoint of cellular aging, endothelial or endocardial function, and fibroblast. Aging-related changes in the cardiovascular system include death and dysfunction of cell, and matrix fibrosis, but these can also be induced by various causes other than aging. To elucidate the relationship between aging and remodeling of the cardiovascular system, firstly, it is necessary to clarify the phenomena of cellular aging. Changes also differ between the heart and arteries, and there are time lags between aging and aging-associated morphological and functional changes in the cardiovascular system: some changes appear early (early type) or later (delayed type) and some changes occur at the same speed with aging (linear type). In this report, the latest findings concerning agingassociated functional and morphological changes in the arteries and the heart are reviewed and the studies are summarized. Arteries and the heart change with aging while interacting with each other. These arterial-cardiac interactions are also described. © 2010 Elsevier Ireland Ltd. All rights reserved. Source

Nagoshi S.,Saitama University
Hepatology Research | Year: 2014

Osteopontin (OPN) is a multifunctional protein, involved in pathological conditions including inflammation, immunity, angiogenesis, fibrosis and cancer progression in various tissues. Hepatic inflammation and fibrosis induced by feeding with a diet deficient in methionine and choline (MCD diet) were markedly attenuated in OPN knockout mice when compared with wild-type mice in the model of non-alcoholic steatohepatitis (NASH). Hepatic cholangiocytes, myofibroblastic stellate cells and natural killer T cells were suggested to secret OPN in mice fed an MCD diet. Plasma and hepatic OPN levels were significantly higher in patients with NASH with advanced fibrosis than in those with early fibrosis. Hepatic OPN mRNA level was correlated with hepatic neutrophil infiltration and fibrosis in patients with alcoholic liver diseases. In those with hepatocellular carcinoma (HCC), OPN levels in plasma and HCC were prognostic factors after liver resection or transplantation. Downregulation of OPN inhibited tumor growth and lung metastasis in nude mice implanted with HCC cells. The single nucleotide polymorphism in the promoter region of the OPN gene was shown to be associated with activity of hepatitis in chronic hepatitis C patients, prognosis in patients with HCC, and growth and lung metastasis of HCC xenografts in nude mice. OPN was reported to be a downstream effecter of Hedgehog pathway, which modulates hepatic fibrosis and carcinogenesis. This review focuses on the roles of OPN in hepatic inflammation, fibrosis and cancer progression. Further elucidation of cellular interactions and molecular mechanisms associated with OPN actions may contribute to development of novel strategies for treatment of the liver diseases. © 2013 The Japan Society of Hepatology. Source

The aromatic compounds have for a long time played important roles in organic chemistry. The skeletons of most aromatic compounds consist mainly of carbon atoms and other second-row elements. However, a recent question is whether the concept of aromaticity can be applied when the carbon atoms of the π-frameworks are substituted by heavier group 14 atoms. In contrast to recent extensive works on the creation of silicon- and germanium-containing carbocyclic π-frameworks, which demonstrated novel heavier aromatic compounds, no one knew whether or not the concept of aromaticity could be applied to tin-containing carbocyclic compounds in 2001. We therefore targeted the synthesis of a dilithiostannole, which is a tin-analog of the cyclopentadienyl anion. Dilithiostannoles and its benzannulated derivatives were successfully synthesized by reduction of the corresponding 1,1-diphenyl derivatives. X-ray diffraction analysis of the dilithiostannoles revealed that each of the stannole rings is almost planar without bond alternation of the C-C bonds. Based on their structural features and very negative nucleus-independent chemical shift (NICS) values calculated at 1.0. Å above the rings, the dilithiostannoles were concluded to be the first tin-containing carbocyclic aromatic compounds. In the benzannulated derivatives, each of the stannole rings is more aromatic than its adjacent benzene ring, as determined by theoretical calculations. The synthesis of dilithioplumbole was also accomplished and it was concluded to have considerable aromatic character, as supported by X-ray diffraction analysis and theoretical calculations. Therefore, the concept of aromaticity is now extended to lead-containing carbocyclic compounds. The reactivity of the dilithio-stannoles and -plumbole is also demonstrated. © 2011 Elsevier B.V. Source

Yoshikawa N.,Saitama University
Applied Optics | Year: 2013

A simple estimation method of the relative phase shift for generalized phase-shifting digital holography based on a statistical method is proposed. This method consists of a selection procedure of an optimum cost function and a simple root-finding procedure. The value and sign of the relative phase shift are determined using the coefficient and the solution of the optimum cost function. The complex field of an object wave is obtained using the estimated relative phase shift. The proposed method lifts the typical restriction on the range of the phase shift due to the phase ambiguity problem. Computer simulations and optical experiments are performed to verify the proposed method. © 2013 Optical Society of America. Source

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