Search Results - (Author, Cooperation:Y. Abe)

2018-01-31

Wiley-Blackwell

0148-0227

Geosciences

Physics

2018-05-07

BMJ Publishing

2044-6055

Medicine

Clinical trials (epidemiology), Open access, Neurology

2018-05-17

Royal Society

2054-5703

Natural Sciences in General

organic chemistry, synthetic chemistry

2013-05-31

Nature Publishing Group (NPG)

0028-0836

1476-4687

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

2015-11-07

American Association for the Advancement of Science (AAAS)

0036-8075

1095-9203

Biology

Chemistry and Pharmacology

Computer Science

Medicine

Natural Sciences in General

Physics

Anion Exchange Protein 1, Erythrocyte/*chemistry/genetics ; Crystallography, X-Ray ; Disease/genetics ; Escherichia coli Proteins/chemistry ; Humans ; Membrane Transport Proteins/chemistry ; Mutation ; Protein Structure, Secondary ; Protein Structure, Tertiary

1089-7550

AIP Digital Archive

Physics

InP crystals were etched by reactive ion etching (RIE) with gas mixture of ethane and hydrogen (C2H6/H2), and etching damages were characterized by photoluminescence (PL) measurements of near-edge and defect-related emissions. Near-edge PL emission intensities after RIE were equal to or larger than those before RIE, except for the samples etched for 50 min. The damage introduced by RIE was restricted to the very-near-surface region which can be removed by HF treatment. The peak energy of defect-related 1.1-eV deep emission bands shifted toward the lower-energy side for the crystals with etching damages at the surface. The peak shift is attributable to the increase of defect complexes such as P-vacancy–P-interstitial or P-vacancy–In-vacancy.

Electronic Resource

1089-7550

AIP Digital Archive

Physics

In order to clarify causes of the slow buildup of the optical output, i.e., slow optical response, in red-emitting CaS:Eu thin-film electroluminescent devices, Eu2+ concentration and temperature dependence of the response time of transferred electrons were measured. It was found that the response time increased exponentially with the increase in Eu2+ concentration and temperature. To understand these results, trapping states in CaS:Eu phosphor layer were studied by measuring temperature dependence of the following electro-optical characteristics with Eu2+ concentration as a parameter; (i) decay profile of trapped electrons, (ii) photoluminescent intensity, and (iii) photoinduced charge density. From these measurements, it was found that there existed two kinds of shallow states in the band gap of CaS. One was electron trapping states located at approximately 0.15 eV below the conduction-band minimum. These states were considered to be generated by Eu2+ clusters. The other was located at 0.06–0.08 eV below the conduction-band minimum. These states were considered to be 5d-excited states of isolated Eu2+ activators. Based on these experimental results, an energy band model for CaS:Eu thin film was proposed and causes for the slow optical response were discussed.

Electronic Resource

1365-2133

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Mixed cryoglobulinaemia is frequently associated with chronic hepatitis. We report a patient with mixed cryoglobulinaemia, hepatitis C virus (HCV) infection and palpable purpura. The skin manifestations were diagnosed as leucocytoclastic vasculitis in view of both the clinical appearance and the histological findings. In this study, we demonstrated the presence of IgG–class anti–HCV–antibody. HCV–RNA and IgA–class rheumatoid factor in the cryoprecipitate. These results suggest that the cryoglobulinaemia in this case was caused by aggregation of an immune complex comprised of HCV and anti–HCV antibody with IgA–type–rheumatoid factor, and that this led to a cutaneous vasculitis.

Electronic Resource

1089-7550

AIP Digital Archive

Physics

The radiative transitions of (100)- and (311)A-oriented three-step asymmetric coupled quantum wells in an electric field are studied by photoluminescence. Four distinct transitions are observed in the spectra which exhibit remarkably complex energy shifts with the applied field. It is shown that these transitions originate from the two pairs of spatially direct and indirect heavy-hole excitons in the three-step quantum well and that their electric-field dependence is dominated by the conversion of the direct into the indirect excitons and vice versa. Furthermore, we discuss the effects of the nonconventional crystal orientation and show that substantial modifications of the basic electro-optical properties can be achieved from internal piezoelectric fields incorporated within the structure.

Electronic Resource

1077-3118

AIP Digital Archive

Physics

Defect formation in dehydrated silica glasses was investigated using various excimer lasers with different energies. The ArF laser (6.4 eV) generates the E' center more effectively than the KrF laser (5.0 eV), while the XeCl laser (4.0 eV) generated no centers. Defect generation was found to be proportional to the square of the laser photon density, indicating that it occurs dominantly due to a two-photon process which makes band-to-band excitation possible. The E' center probably originated from oxygen-deficient centers. Contributions to the E' center formation from a process involving direct absorption at the sites of intrinsic defects in SiO2 glass were discussed on the basis of the excitation energy dependence and a comparison with the effect of a low-pressure mercury lamp.

Electronic Resource

1077-3118

AIP Digital Archive

Physics

The specific lattice location of Zn in CdTe single crystals has been investigated by ion-channeling methods combined with particle-induced x-ray emission. Observing the asymmetry effects of channeling dips around the [110] axis and analyzing the asymmetry factors for host atoms and doped Zn atoms, it is revealed that almost all Zn atoms occupy the Cd sublattice sites, and Zn-doped CdTe crystals grown by vertical Bridgman methods appear to be almost completely free from the segregation of doped Zn atoms.

Electronic Resource

1089-7550

AIP Digital Archive

Physics

Using ion-channeling methods, the thermal stability of crystallinity for heavily Ga-doped ZnSe epitaxial layers grown on GaAs (100) substrates was investigated. Some distinctive features were found: The crystallinity of as-grown heavily Ga-doped ZnSe is similar to that of undoped ZnSe. After thermal annealing at 450 °C, the crystallinity of Ga-doped ZnSe is degraded, although that of undoped ZnSe is not significantly changed. It is expected that doped Ga atoms are displaced from the regular lattice sites after annealing. The degree of this degradation depends on the crystallinity of the as-grown Ga-doped ZnSe itself. These results indicate the degradation of the crystallinity for Ga-doped ZnSe epilayers is mainly caused by the interaction between the doped Ga atoms and grown-in point defects in the epitaxial layers. © 1997 American Institute of Physics.

Electronic Resource

1089-7623

AIP Digital Archive

Physics

Electrical Engineering, Measurement and Control Technology

The effect of field irregularity due to the use of conducting meshes to cover holes of a lower electrode in a parallel-plate electrostatic analyzer, is experimentally and numerically investigated. Displacement of a focal point and degradation of analyzer characteristics are found in the experiment. Dependence of analyzer characteristics on wire spacing is obtained. Primary results are also confirmed by numerical analysis. Criteria for error estimation are theoretically derived and found to be consistent with the experiment.

Electronic Resource

1077-3118

AIP Digital Archive

Physics

Silicate glasses, Al2O3⋅9SiO2, were successfully prepared to incorporate Sm2+ ions using a sol-gel process. The glasses synthesized through hydrolysis of Si(OC2H5)4, Al(OC4H9)3, and SmCl3⋅6H2O were heated in air, followed by heating in the presence of hydrogen, in which samarium ions were reduced from the trivalent to divalent state. Glasses incorporated with Sm2+ were colorless, transparent, and showed an intense emission with peaks at 683, 700, and 725 nm due to 5D0→7F0,1,2 transitions, respectively, of the Sm2+ ions. Irradiating the glasses with an Ar laser lowered the intensities of emission from Sm2+ ions and did not promote the formation of Sm3+ ions.

Electronic Resource

1089-7623

AIP Digital Archive

Physics

Electrical Engineering, Measurement and Control Technology

A new modification on the parallel plate analyzer for 500 keV heavy ions to eliminate the effect of the intense UV and visible radiation, is successfully implemented. Its design principle and results of numerical optimization are presented. In addition, the analyzer characteristics experimentally obtained in a high temperature plasma device, are discussed.

Electronic Resource

1089-7550

AIP Digital Archive

Physics

Residual Ga and As atoms in SiOx and SiNy dielectric films deposited on GaAs were investigated by Rutherford backscattering spectroscopy and particle-induced x-ray emission techniques. Both Ga and As atoms were detected in the films after high temperature heat treatment, and even in the films as-deposited. The magnitude of the residual atoms presumably out-diffused from GaAs substrates was of the order of 1×1019 /cm3. The concentration of Ga atoms prevails over that of As atoms in SiOx/GaAs systems as is generally known, and vice versa in SiNy/GaAs systems after heat treatment. Dynamic behavior of Ga and As atoms in the films as functions of annealing temperature and annealing time cannot be explained by a simple diffusion mechanism. A model is proposed that the damaged layer around the interface of the systems is responsible for the anomalous out-diffusion phenomena.

Electronic Resource

1089-7550

AIP Digital Archive

Physics

The combination experiments of ac and dc (as the thermally stimulated polarization current) suggest that, by the dc process, there appeared the positive and negative ion-depleted region at the interface between glass bulk and the positive ion-depleted region near the anode. This may be the ionic analog for a p-n junction under reverse bias of a semiconductor. The relaxation in polarized glass would take place by the annihilation of the positive and negative ion-depleted region by back-diffusion of oxygen ions from the positive ion-depleted region and of sodium ions from the bulk.

Electronic Resource

1089-7666

AIP Digital Archive

Physics

Gradient-driven instabilities and the subsequent nonlinear evolution of generated vortices in sheared E×B flows are investigated for magnetized plasmas with and without gravity (magnetic curvature) and magnetic shear by using theory and implicit particle simulations. In the linear eigenmode analysis, the instabilities considered are the Kelvin–Helmholtz (K–H) instability and the resistive interchange instability. The presence of the shear flow can stabilize these instabilities. The dynamics of the K–H instability and the vortex dynamics can be uniformly described by the initial flow pattern with a vorticity localization parameter ε. The observed growth of the K–H modes is exponential in time for linearly unstable modes, secular for the marginal mode, and absent until driven nonlinearly for linearly stable modes. The distance between two vortex centers experiences rapid merging while the angle θ between the axis of the vortices and the external shear flow increases. These vortices proceed toward their overall coalescence, while shedding small-scale vortices and waves. The main features of vortex dynamics, the nonlinear coalescence and the tilt or the rotational instabilities of vortices, are shown to be given by using a low-dimension Hamiltonian representation for interacting vortex cores in the shear flow.

Electronic Resource

1365-3040

Blackwell Publishing Journal Backfiles 1879-2005

Biology

The spadix of skunk cabbage, Symplocarpus foetidus, is capable of maintaining an internal temperature of around 20 °C even when the ambient temperature drops to around 0 °C. To determine the crucial structure that is required for detection of ambient temperature signals, detailed measurements of the temperatures of the spadix were made under field conditions. The spadix temperature was well regulated even when the spathe or the leaf of the plant was removed. Furthermore, maintenance of the temperature of the central stalk at either 10 or 20 °C had no effect on the thermoregulation when the ambient temperature increased from 10 to 25 °C or decreased from 20 to 8 °C. Therefore, it seemed that the heat production in the spadix required neither the spathe, the leaf, nor the central stalk for perception of the external temperature signals. Finally, analysis of sugar composition in xylem exudates showed that the concentrations of sucrose, glucose, and fructose, all of which are potential energy sources of thermogenesis, did not change significantly at different ambient temperatures. It is concluded that the spadix is a unique organ in which the perception of ambient temperature signals and heat production occurs in S. foetidus.

Electronic Resource

1365-3040

Blackwell Publishing Journal Backfiles 1879-2005

Biology

Abstract. Germination modes of lower seeds of cocklebur (Xanthium pennsylvanicum Wallr.) under different water stresses, prepared with mannitol solution, were examined in relation to gaseous factors. As the concentration of mannitol increased, germination was increasingly inhibited at a mode which was drawn by two straight lines having different slopes and meeting at an angle. One is a sharp line occurring at the lower concentrations of mannitol; the other is a gentle line occurring at higher concentrations of mannitol. The former reflected the growth response of axial tissues to mild water stress, whereas the latter reflected the growth response of cotyledonary tissues to severe water stress. The germination potential of cocklebur seeds increased with increasing temperature. Thus, the seeds were more resistant to water stress at higher than al lower temperatures. This increased germination potential under water stress resulted from the greater growth potential of axial tissues, but not cotyledonary tissues, at higher temperature. Increased O2 levels improved both the reduced axial and cotyledonary growth under water stress. Carbon dioxide predominantly enhanced axial growth under water stress, whereas C2H4 exclusively enhanced cotyledonary growth. Thus, these gases were effective in potentiating germination under water stress. When combined with each other, these gases caused more pronounced growth of the axial and cotyledonary tissues, leading to germination under more severe water stresses. Maximal axial and cotyledonary growth under water stress occurred in the simultaneous presence of CO2, C2H4 and O2, which allowed the germination at higher mannitol concentrations above 0.6 kmol m−3 From these results, it was suggested that cocklebur seeds would override water stress by depending upon both the Corresponding axial growth and the C2H4-responding cotyledonary growth.

Electronic Resource