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Search Results: 1 - 10 of 776 matches for " Tetsuo Miyakoshi "
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Studies on Acetone Powder and Purified Rhus Laccase Immobilized on Zirconium Chloride for Oxidation of Phenols
Rong Lu,Tetsuo Miyakoshi
Enzyme Research , 2012, DOI: 10.1155/2012/375309
Abstract: Rhus laccase was isolated and purified from acetone powder obtained from the exudates of Chinese lacquer trees (Rhus vernicifera) from the Jianshi region, Hubei province of China. There are two blue bands appearing on CM-sephadex C-50 chromatography column, and each band corresponding to Rhus laccase 1 and 2, the former being the major constituent, and each had an average molecular weight of approximately 110?kDa. The purified and crude Rhus laccases were immobilized on zirconium chloride in ammonium chloride solution, and the kinetic properties of free and immobilized Rhus laccase, such as activity, molecular weight, optimum pH, and thermostability, were examined. In addition, the behaviors on catalytic oxidation of phenols also were conducted. 1. Introduction Rhus laccase (EC.1.10.3.2) is a copper-containing glycoprotein occurring in the exudates of lacquer trees. Yoshida [1] first discovered the enzyme in 1883. Since then, many studies of the enzyme have been conducted. However, the results obtained so far in different laboratories frequently show considerable discrepancies. For example, the molecular weight reported varies from 100 to 141?kDa [2–4], and the properties of coppers differ considerably depending on the origin of the laccase preparations [5, 6]. Previously, when the Rhus laccase from Japanese lacquer trees was used to oxidize urushiol, the formation of semiquinone radicals, C–C or C–O coupling products, and dibenzofuran compounds were detected [7]. The enzyme laccase, whether obtained from a lacquer tree or fungus, is active in the oxidation of monophenolic compounds such as eugenol and isoeugenol [8]. The laccase-catalyzed oxidation of O-phenylenediamine [9], coniferyl alcohol [10], catechol [11], phenylpropanoid [12], and lignocatechol [13] were also demonstrated. Studies of the effects of proteins and polysaccharides in the activities of Rhus laccase showed that most proteins and polysaccharides, except laccase proteins, are not only incapable of catalyzing the oxidation of urushiol but can inhibit the activity of laccase to varying extents [14]. Recently, we immobilized Rhus laccase from acetone powder obtained from the exudates of lacquer trees grown in the Maoba region, Hubei province of China, on water-soluble chitosan and chitosan microspheres, and their properties were compared with transitional metal (Fe3+)-immobilized laccase by chelation [15]. The results showed that, compared with the free Rhus laccase, immobilized Rhus laccase displayed a lower specific activity but has a similar substrate affinity with improved stability
Application of Pyrolysis Gas Chromatography/Mass Spectrometry in Lacquer Research: A Review
Xiao-Ming Ma,Rong Lu,Tetsuo Miyakoshi
Polymers , 2014, DOI: 10.3390/polym6010132
Abstract: Examination of thermal degradation of natural and synthetic lacquer films by pyrolysis-gas chromatography with mass spectrometry (Py-GC/MS) is reviewed. Due to the instantaneous heating decomposition, side reactions of internal or intermediate samples hardly occur, and the pyrolysis products can be retrieved without any change. Py-GC/MS has been used to analyze the composition of insoluble polymers and investigate degradation of resin materials. Lacquer film is a cross-linked polymer that is insoluble in any solvent. The aim of this review is to describe the application of Py-GC/MS to the analysis of lacquer, including natural lacquer saps, synthetic lacquer derivatives, and their films. After analyzing the chemical structures of the specific pyrolysis products by mass spectrometry, the lacquer tree species and growing region can be determined. These results have great significance for the protection and restoration of lacquer-coated cultural treasures.
The review of cellular effects of a static magnetic field
Junji Miyakoshi
Science and Technology of Advanced Materials , 2006,
Abstract: The effects of static magnetic fields at the cellular level are reviewed. Past studies have shown that a static magnetic field alone does not have a lethal effect on the basic properties of cell growth and survival under normal culture conditions, regardless of its magnetic density. It has also been shown that cell cycle distribution is not influenced by extremely strong static magnetic fields (up to a maximum of 10 tesla (T)). A further area of interest is whether static magnetic fields cause DNA damage, which can be evaluated by determination of the frequency of micronucleus formation. The presence or absence of such micronuclei can confirm whether a particular treatment damages cellular DNA. This method has been used to confirm that a static magnetic field alone has no such effect. However, the frequency of micronucleus formation changes significantly when certain treatments (for example, X-irradiation and mitomycin C) are given during exposure to a strong static magnetic field. It has also been reported that treatment with trace amounts of ferrous ions in the cell culture medium and exposure to a static magnetic field increases DNA damage, which is detected using the comet assay. Several reports suggest that a strong static magnetic field may affect the ion transport and the gene expression. In addition, many studies have found a strong magnetic field can induce orientation phenomena in cell culture.
Remarks on the Erroneous Dispersion Surfaces From a Pair of a Hyperbolic Branch and An Elliptical Arc of the Intersected Two Laue Spheres Based on the Usual Crude Approximation  [PDF]
Tetsuo Nakajima
Journal of Modern Physics (JMP) , 2011, DOI: 10.4236/jmp.2011.23022
Abstract: In almost all previous works, the hyperbolic dispersion surfaces of the central proper quadrics have been crudely derived from the degree of reduction from the bi-quadratic equation by use of some roughly indefinable approximate relations. Moreover, neglecting the high symmetry of the hyperbola, both the branches have been approximated on the asymmetric surfaces composed of a pair of a branch of the hyperbola and a vertex of the ellipse without the presentation of reasonable evidence. Based upon the same dispersion surfaces equation, a new original gapless dispersion surfaces could be rigorously introduced without crude omission of even a term in the bi-quadratic equation based upon usual analogy with the extended band theory of solid as the close approximation to the truth.
Japanese Social Expenditure under Rapid Population Ageing  [PDF]
Tetsuo Fukawa
Open Journal of Social Sciences (JSS) , 2015, DOI: 10.4236/jss.2015.311018
Abstract: Japan is suffering from low fertility for more than two decades, and Japanese social security system needs a structural reform to be more effective and sustainable. In this paper, we discussed structural issues in the Japanese social security system, which will provide the basis for containing social expenditure in Japan. Some Japanese benefits, such as child-rearing support and benefit for low income families as well as long-term care benefit, need to be increased. On the other hand, it is important to incorporate right incentives in the system for healthcare and LTC services, and new forms of solidarity are indispensable to make Japanese social security system sustainable.
Distributive Impact of Low-Income Support Measures in Japan  [PDF]
Tetsuo Fukawa
Open Journal of Social Sciences (JSS) , 2016, DOI: 10.4236/jss.2016.412002
Abstract:
Population decline together with rapid aging has a strong cost push pressure on social security systems in Japan. Effective measures to support low-income families are quite important to mitigate income inequality and to overcome low fertility in Japan. Using the micro-data of the Basic Household Survey 2010, we analyse various measures to support low income families through various simulations concerning child allowance, social security contributions, and income taxes. Based on the simulation results, we discussed distributive impact of such measures and their policy implications.
Elderly Population Projection and Their Health Expenditure Prospects in Japan  [PDF]
Tetsuo Fukawa
Modern Economy (ME) , 2017, DOI: 10.4236/me.2017.811085
Abstract: By using a dynamic micro-simulation model named INAHSIM-II, we conducted a population-household projection in Japan (INAHSIM 2017) for the period of 2015-2065. Due to rapid aging of the population, the distribution of the elderly (65 years old or older) by dependency level has a profound impact on health expenditure (namely medical expenditure and long-term care expenditure) of the elderly. In this paper, we estimated health expenditure of the elderly in 2025-2065, using the results of the projection of the elderly by dependency level.
Antiferromagnetic topological insulator state in the correlated Bernevig-Hughes-Zhang model
S. Miyakoshi,Y. Ohta
Physics , 2013, DOI: 10.1103/PhysRevB.87.195133
Abstract: We study the effects of electron correlations on the topological phase transition in the Bernevig-Hughes-Zhang model using the variational cluster approach where the short-range spatial correlations are taken into account exactly. We calculate the spin Chern number and local magnetic moment to show that the topologically nontrivial antiferromagnetic order exists and that the magnetic transition is of the second order. We furthermore demonstrate that under the spin-quantized condition the topological phase transition is caused by the closing of the bulk band gap.
FRAX and Exercise: Should Exercise Be Categorized as a Risk Factor in Osteoporotic Patients  [PDF]
Akira Horikawa, Naohisa Miyakoshi, Yoichi Shimada, Hiroyuki Kodama
Open Journal of Orthopedics (OJO) , 2013, DOI: 10.4236/ojo.2013.32025
Abstract:

Although FRAX (WHO Fracture Risk assessment Tool), developed by the WHO, is a well-validated tool for determining the probability of a major osteoporotic fracture in the next 10 years, it doesn’t include a number of other impact factors such as exercise and nutrition. The purpose of this study was to compare the differences in FRAX between subjects with and without exercise habits or intake of calcium/coffee. A significant difference in FRAX was observed between the groups with respect to exercise (p < 0.001). There were no significant differences in FRAX, however, between the groups with and without intake of calcium/coffee. Although exercise habits are not included in FRAX, our findings suggest that exercise status influenced other factors included in FRAX. Since exercise is reported to prevent falls and fall-related osteoporotic fractures, including exercise status in FRAX may be more effective for estimating the possibility of future fractures. Further investigation should be conducted to determine whether exercise status is an important risk factor, independent of FRAX, for osteoporotic fractures.

Eosinophilic Granuloma Arising from the Sacrum: A Case Report  [PDF]
Yuji Kasukawa, Naohisa Miyakoshi, Michio Hongo, Shigeru Ando, Yoshinori Ishikawa, Yoichi Shimada
Open Journal of Orthopedics (OJO) , 2011, DOI: 10.4236/ojo.2011.12002
Abstract: Introduction: Osseous eosinophilic granulomas commonly occur in the skull, pelvis, vertebrae, mandible, and ribs. However, the eosinophilic granuloma in the sacrum is rare. Case presentation: We present the case of a 13-year-old Japanese boy, who presented with left low-back pain, and was diagnosed with eosinophilic granuloma arising in the sacrum. Computed tomography (CT) and magnetic resonance imaging demonstrated an osteolytic lesion with interruption of the cortex, and signal intensity changes at the left sacral body and wing. Histologic examination indicated an eosinophilic granuloma. Two years after CT-guided biopsy, the tumor had spontaneously healed completely, with no residual pain.Conclusion: The present case was eosiophilic granuloma arising from the rare site of sacrum. The tumor was completely remodeled two years after biopsy.
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