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Search Results: 1 - 10 of 118163 matches for " T. Takayama "
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Numerical Study on Aging Dynamics in the 3D Ising Spin-Glass Model --- Quasi-Equilibrium Behaviour of Spin Auto-Correlation Functions
H. Takayama,H. Yoshino,T. Komori
Physics , 1999, DOI: 10.1142/S0129183199001212
Abstract: Using Monte Carlo simulations, we have studied aging phenomena in three-dimensional Gaussian Ising spin-glass model focusing on quasi-equilibrium behavior of the spin auto-correlation functions. Weak violation of the time translational invariance in the quasi-equilibrium regime is analyzed in terms of effective stiffness for droplet excitations in the presence of domain walls. The simulated results in not only isothermal but also $T$-shift aging processes exhibit the expected scaling behavior with respect to the characteristic length scales associated with droplet excitations and domain walls in spite of the fact that the growth law for these length scales still shows a pre-asymptotic behavior compared with the asymptotic form proposed by the droplet theory. Implications of our simulational results are also discussed in relation to experimental observations.
Bose-Fermi mixed condensates of atomic gas with Boson-Fermion quasi-bound state
H. Yabu,Y. Takayama,T. Suzuki
Physics , 2004, DOI: 10.1016/S0921-4526(02)01878-1
Abstract: The phase structures of the boson-fermion (B and F) mixed condensates of atomic gas are discussed under the existence of boson-fermion composite fermions (quasi-bound states) BF from the equilibrium in B+F -> BF. Especially we discuss the competitions between the BF degenerate states and the Bose-Einstein condensates (BEC) in low-T. The criterion for the BEC realization is obtained from the algebraically-derived phase diagrams at T=0.
Polynomial and rational solutions of holonomic systems
T. Oaku,N. Takayama,H. Tsai
Mathematics , 2000,
Abstract: The aim of this paper is to give two new algorithms, which are elimination free, to find polynomial and rational solutions for a given holonomic system associated to a set of linear differential operators in the Weyl algebra D = k where k is a subfield of the complex numbers.
One-Dimensional Edge States with Giant Spin Splitting in a Bismuth Thin Film
A. Takayama,T. Sato,S. Souma,T. Oguchi,T. Takahashi
Physics , 2015, DOI: 10.1103/PhysRevLett.114.066402
Abstract: To realize a one-dimensional (1D) system with strong spin-orbit coupling is a big challenge in modern physics, since the electrons in such a system are predicted to exhibit exotic properties unexpected from the 2D or 3D counterparts, while it was difficult to realize genuine physical properties inherent to the 1D system. We demonstrate the first experimental result that directly determines the purely 1D band structure by performing spin-resolved angle-resolved photoemission spectroscopy of Bi islands on a silicon surface that contains a metallic 1D edge structure with unexpectedly large Rashba-type spin-orbit coupling suggestive of the nontopological nature. We have also found a sizable out-of-plane spin polarization of the 1D edge state, consistent with our first-principles band calculations. Our result provides a new platform to realize exotic quantum phenomena at the 1D edge of the strong spin-orbit-coupling systems.
Treatment of peripheral exudative hemorrhagic chorioretinopathy by intravitreal injections of ranibizumab
Takayama K, Enoki T, Kojima T, Ishikawa S, Takeuchi M
Clinical Ophthalmology , 2012, DOI: http://dx.doi.org/10.2147/OPTH.S31640
Abstract: eatment of peripheral exudative hemorrhagic chorioretinopathy by intravitreal injections of ranibizumab Case report (1983) Total Article Views Authors: Takayama K, Enoki T, Kojima T, Ishikawa S, Takeuchi M Published Date June 2012 Volume 2012:6 Pages 865 - 869 DOI: http://dx.doi.org/10.2147/OPTH.S31640 Received: 09 March 2012 Accepted: 30 March 2012 Published: 07 June 2012 Kei Takayama,1 Tosio Enoki,1,2 Teruo Kojima,1,2 Sho Ishikawa,1 Masaru Takeuchi,1 1Department of Ophthalmology, National Defense Medical College, Saitama, Japan; 2Enoki Clinic, Saitama, Japan Abstract: Peripheral exudative hemorrhagic chorioretinopathy (PEHCR) is a rare disorder that sometimes causes sudden subretinal and/or vitreous hemorrhage. Choroidal neovascularization is involved in the pathogenesis, but the etiology is unknown. Treatments with photocoagulation, cryopexy, and intravitreal bevacizumab injection have been reported. However, the therapeutic effect of intravitreal injection with ranibizumab for PEHCR is unclear. A 70-year-old woman visited our department because of sudden loss of superior visual field in her left eye. She had a history of surgical removal of hematoma due to subretinal hemorrhage associated with age-related macular degeneration 5 years ago. Peripheral subretinal hemorrhage was observed in the left eye, and fluorescein and indocyanine green angiography revealed choroidal neovascularization in the subretinal hemorrhagic region. PEHCR was diagnosed. Considering her past history, intravitreal ranibizumab injection was used for treatment. After three injections in the left eye, subretinal hemorrhage and choroidal neovascularization resolved completely. No recurrence was observed during 1 year of follow-up. This case demonstrates that intravitreal injection of ranibizumab is an effective treatment for PEHCR with subretinal hemorrhage.
Human amniotic epithelial cells are morphologically homogeneous: enzymehistochemical, tracer, and freeze-substitution fixation study
R Iwasaki,S Matsubara,T Takizawa,T Takayama
European Journal of Histochemistry , 2003, DOI: 10.4081/831
Abstract: We examined the fine subcellular morphology of human amniotic epithelial cells and attempted to answer the question as to whether amniotic epithelial cells consist of heterogeneous or homogeneous cells, which has long been controversial. Study subjects were fetal membranes from pregnant women (n=18) who abdominally gave birth to healthy infants at term (37.9±0.7 weeks of gestation, mean±sd). The methods employed were transmission electron microscopy, enzymehistochemistry, tracer permeability analysis, and freeze-substitution fixation. The labelings for acid phosphatase, cytochrome c oxidase, and CA++ATPase were seen in the lysosomes, mitochondria, and lateral plasma membranes, respectively. The staining distribution pattern of these three enzymes and the morphology of the organelle highlighted by these enzymehistochemistry did not differ among cells. Freeze-substitution fixation revealed that intercellular spaces in the amniotic epithelial cells were narrower than previously thought, but the tracers (horse radish peroxidase and lanthanum nitrate) fully entered these spaces. There were no variations in the tracer permeability among cells. All cells from freeze-substitution fixation exhibited the same morphological features. From these morphological viewpoints, we conclude that human term amniotic epithelial cells consist of a homogeneous cell population.
Treatment of peripheral exudative hemorrhagic chorioretinopathy by intravitreal injections of ranibizumab
Takayama K,Enoki T,Kojima T,Ishikawa S
Clinical Ophthalmology , 2012,
Abstract: Kei Takayama,1 Tosio Enoki,1,2 Teruo Kojima,1,2 Sho Ishikawa,1 Masaru Takeuchi,11Department of Ophthalmology, National Defense Medical College, Saitama, Japan; 2Enoki Clinic, Saitama, JapanAbstract: Peripheral exudative hemorrhagic chorioretinopathy (PEHCR) is a rare disorder that sometimes causes sudden subretinal and/or vitreous hemorrhage. Choroidal neovascularization is involved in the pathogenesis, but the etiology is unknown. Treatments with photocoagulation, cryopexy, and intravitreal bevacizumab injection have been reported. However, the therapeutic effect of intravitreal injection with ranibizumab for PEHCR is unclear. A 70-year-old woman visited our department because of sudden loss of superior visual field in her left eye. She had a history of surgical removal of hematoma due to subretinal hemorrhage associated with age-related macular degeneration 5 years ago. Peripheral subretinal hemorrhage was observed in the left eye, and fluorescein and indocyanine green angiography revealed choroidal neovascularization in the subretinal hemorrhagic region. PEHCR was diagnosed. Considering her past history, intravitreal ranibizumab injection was used for treatment. After three injections in the left eye, subretinal hemorrhage and choroidal neovascularization resolved completely. No recurrence was observed during 1 year of follow-up. This case demonstrates that intravitreal injection of ranibizumab is an effective treatment for PEHCR with subretinal hemorrhage.Keywords: peripheral exudative hemorrhagic chorioretinopathy, ranibizumab, intravitreal injection, choroidal neovascularization
Large-scale electronic-structure theory and nanoscale defects formed in cleavage process of silicon
T. Hoshi,R. Takayama,Y. Iguchi,T. Fujiwara
Physics , 2005, DOI: 10.1016/j.physb.2005.12.243
Abstract: Several methods are constructed for large-scale electronic structure calculations. Test calculations are carried out with up to 10^7 atoms. As an application, cleavage process of silicon is investigated by molecular dynamics simulation with 10-nm-scale systems. As well as the elementary formation process of the (111)-(2 x 1) surface, we obtain nanoscale defects, that is, step formation and bending of cleavage path into favorite (experimentally observed) planes. These results are consistent to experiments. Moreover, the simulation result predicts an explicit step structure on the cleaved surface, which shows a bias-dependent STM image.
Goldilocks Supersymmetry: Simultaneous Solution to the Dark Matter and Flavor Problems of Supersymmetry
Feng, Jonathan L.;Smith, Bryan T.;Takayama, Fumihiro
High Energy Physics - Phenomenology , 2007, DOI: 10.1103/PhysRevLett.100.021302
Abstract: Neutralino dark matter is well motivated, but also suffers from two shortcomings: it requires gravity-mediated supersymmetry breaking, which generically violates flavor constraints, and its thermal relic density \Omega is typically too large. We propose a simple solution to both problems: neutralinos freezeout with \Omega ~10-100, but then decay to ~1 GeV gravitinos, which are simultaneously light enough to satisfy flavor constraints and heavy enough to be all of dark matter. This scenario is naturally realized in high-scale gauge-mediation models, ameliorates small scale structure problems, and implies that ``cosmologically excluded'' models may, in fact, be cosmologically preferred.
Chorion laeve trophoblasts of preeclamptic fetal membranes: histochemically detectable enzyme activities do not change at a subcellular level
S Matsubara,T Takayama,R Iwasaki,A Izumi
European Journal of Histochemistry , 2009, DOI: 10.4081/1631
Abstract: We examined the subcellular localization of ADPdegrading activity and cytochrome c oxidase (CCO) activity in chorion laeve trophoblasts from term and near term human fetal membranes, and compared them with those from severe preeclamptic fetal membranes. The methods used for the detection of enzyme activities were the lead nitrate method for ADP-degrading activity and the diaminobenzidine method for CCO. Precipitates indicative of ADP-degrading activity were visible on surface microvillous plasma membranes of chorion laeve trophoblasts both from normal and preeclamptic fetal membranes. The intensity and distribution patterns were the same in the normal and preeclamptic subjects. CCO labeling was visible in almost all laeve trophoblastic mitochondria both in normal and preeclamptic cases. Previously, we demonstrated that in preeclamptic villous trophoblasts there were decreases in ADP-degrading activity and the presence of CCO-negative mitochondria, which were proposed to lead to dysfunction of each villous trophoblast, and finally to placental insufficiency in preeclampsia. Reductions or changes in enzyme intensities/distribution patterns, which are characteristic features of preeclamptic villous trophoblasts, were absent in chorion laeve trophoblasts in preeclampsia. These results suggest that in preeclampsia there are no, or at least less severe, abnormalities in the enzyme activities of chorion laeve trophoblasts, compared with villous trophoblasts, as far as enzyme-histochemically detectable enzymes are concerned.
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