Search Results - (Author, Cooperation:K. Sakai)

2018-03-06

The American Society for Microbiology (ASM)

0099-2240

1098-5336

Biology

2018-03-16

The American Society for Microbiology (ASM)

0270-7306

1098-5549

Biology

Medicine

2018-02-17

Institute of Physics Publishing (IOP)

1748-0221

Physics

2018-03-28

American Physical Society (APS)

0556-2813

1089-490X

Physics

Nuclear Reactions

2015-10-24

American Association for the Advancement of Science (AAAS)

0036-8075

1095-9203

Biology

Chemistry and Pharmacology

Computer Science

Medicine

Natural Sciences in General

Physics

Animals ; Basic Helix-Loop-Helix Transcription Factors/genetics/metabolism ; Brain Stem/cytology/physiology ; Cell Lineage ; Cell Separation ; Female ; Glutamates/metabolism ; Male ; Mice ; Mice, Transgenic ; Neurons/metabolism/*physiology ; Pons/cytology/physiology ; Rhombencephalon/*cytology/*embryology ; Sleep, REM/*physiology ; Wakefulness/*physiology ; gamma-Aminobutyric Acid

2018-06-02

The American Association for Cancer Research (AACR)

1078-0432

1557-3265

Medicine

2018-02-14

The American Society for Microbiology (ASM)

0022-538X

1098-5514

Medicine

2018-02-14

The American Society for Microbiology (ASM)

0022-538X

1098-5514

Medicine

1089-7623

AIP Digital Archive

Physics

Electrical Engineering, Measurement and Control Technology

A design of a microspectrophotometric system using a synchrotron radiation (SR) source is described. The system covers a wide spectral range of 50–13000 cm−1, being under construction at the UVSOR BL6B beamline in the Institute for Molecular Science. Preliminary experiments in the mid-infrared region (500–5000 cm−1) have qualitatively confirmed the theoretical calculation that the synchrotron radiation is more intense than a blackbody (T=1200 K) when a microspectrophotomeric technique is applied, which is due to natural collimation and high brilliance of SR source. The SR as an infrared source exhibits its advantage on measuring the spectra of small single crystals especially in the far-infrared region.

Electronic Resource

1089-7623

AIP Digital Archive

Physics

Electrical Engineering, Measurement and Control Technology

Light scattering measurements using an infrared laser light and a bias light have been carried out for the first time to investigate defect energy levels in indium-doped GaAs crystals. The principle of this method is based on the analysis of scattered light intensity variation induced by the bias light. A drastic quenching effect is observed at some wavelength of the bias light. It was found that there are two kinds of light scattering centers in as-grown indium-doped GaAs crystals. © 2000 American Institute of Physics.

Electronic Resource

1089-7623

AIP Digital Archive

Physics

Electrical Engineering, Measurement and Control Technology

A system of optical beating spectroscopy has been newly developed for hyper-resolution Brillouin scattering. Frequency resolution as high as 1 kHz was obtained, far beyond the limit of the classical Fabry–Perot interferometer which is commonly used in ordinary experiments. This system is useful over the frequency range from 104 to 109 Hz at present. Experiments for Rayleigh and/or Brillouin spectra were performed in water, toulene, and carbon disulfide to demonstrate the performance of this system.

Electronic Resource

1471-4159

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Abstract: Rats fed either a safflower oil (α-linolenate-deficient) or a perilla oil (α-linolenate-sufficient) diet through two generations (F1) showed significant differences in the brightness-discrimination learning task. In this task, correct responses were lever-pressing responses, which were reinforced with dietary pellets, and incorrect responses were those with no reinforcement. The inferior learning performance in the safflower oil group was caused mainly by the inferior ability to rectify the incorrect responses through the learning sessions. In the safflower oil group after the learning task, the average densities of synaptic vesicles in the terminals of the hippocampus CA1 region were decreased by nearly 30% as compared with those in the perilla oil group, and it is notable that this difference was not detected without the learning task. These results suggest that dietary oil-induced morphological changes in synapses in the hippocampus of rats are related to the differential learning performance and that the turnover rate of synaptic vesicles in the hippocampus may be an important factor affecting learning performance.

Electronic Resource

1077-3118

AIP Digital Archive

Physics

Changes in size and shape of oxygen precipitates in Czochralski silicon after high-temperature annealing in an Ar atmosphere were observed using a transmission electron microscopy. The oxide precipitates introduced by 750 °C after 4 h annealing in an Ar atmosphere had their corners rounded off by thermal annealing at 1200 °C, and disappeared by 1300 °C although we observed no change in shape at 1050 °C. © 1999 American Institute of Physics.

Electronic Resource

1089-7550

AIP Digital Archive

Physics

Terahertz radiation emitted by coherent phonons in Te, PbTe, and CdTe has been investigated by using an ultrafast photoconductive sampling detector. Pronounced coherent radiation originating from the longitudinal optical (LO) phonon oscillations of infrared-active modes was observed for all samples, irrespective of the different crystal structures. In addition, spectral dips at the transverse optical (TO) phonon frequencies, which could not be explained by absorption in the emitting volume, were observed for all samples. The model calculations indicate that the emission rate of the radiation into the air to that into the dielectric (semiconductor) side is scaled by 1/{1+(nd2+κd2)nd3} (nd and κd are the real and imaginary part of the complex refractive index, respectively). Thus, the enhanced emission of radiation by the coherent LO phonons and the spectral dips at the TO phonon frequencies can be explained by the respective increase and reduction of the emission efficiency of the radiation to the air due to the small and large value of the dielectric constant |εd(ω)|=nd2+κd2 near the LO and TO phonon frequencies, respectively. © 1998 American Institute of Physics.

Electronic Resource

1077-3118

AIP Digital Archive

Physics

Reproducible memory switching has been observed in metal/ Langmuir–Blodgett (LB) film/metal sandwich structures: LB films consist of organic molecules such as dyes having a number of conjugated bonds. The device switches from a nonconducting off state to a conducting on state via an intermediate state, and it switches directly from the on to the off state within less than 10 ns upon the application of a voltage. Both off-state and on-state resistances of the device depend linearly on the number of monolayers, the conduction being predominantly through the LB films.

Electronic Resource

1089-7623

AIP Digital Archive

Physics

Electrical Engineering, Measurement and Control Technology

A new light scattering system was developed to investigate the propagation of liquid surface waves over a wide wave-number range 4×104–3×106 m−1 (or 10 kHz–6 MHz in frequency). Thermal fluctuation of liquid surface displacement excites a surface tension wave called a "ripplon'' whose behavior yields information on the dynamics of the liquid surface. The transmission diffraction method and some optical and electrical improvements are successfully applied to the light scattering system and the upper limit of the frequency measured was extended about two orders higher than the conventional one. The wave-number dependence of the ripplon frequency and damping constant was measured for several kinds of liquids and the results agreed well with the classical hydrodynamic theory.

Electronic Resource

1089-7623

AIP Digital Archive

Physics

Electrical Engineering, Measurement and Control Technology

A grazing incidence constant deviation monochromator with a spherical concave grating was fabricated for use with undulator radiation. It has a simple scanning mechanism with fixed entrance and exit slits, as well as fixed directions of incident and exit beams. It has been installed into an undulator beamline at IMS. Synchrotron radiation from a bending section also can be introduced into the monochromator by using premirrors. The energy resolution of the monochromator is better than 70 meV at the photon energy of 94 eV with 10-μm slits, when the bending magnet synchrotron radiation is used. The spot size of the zeroth-order light is 1.5(v)×2.0(h) mm2 at the distance of 1.85 m behind a postmirror. The photon flux of the undulator radiation behind the exit slit is approximately 1×1012 photons/s at the peak, when both the entrance and exit slits are 100 μm (ΔE=0.08 eV) and the stored current is 50 mA.

Electronic Resource

1089-7623

AIP Digital Archive

Physics

Electrical Engineering, Measurement and Control Technology

A 2.2-m Rowland-circle grazing-incidence monochromator with a fixed entrance slit and a fixed grating, has been installed on the beamline BL8B1 at UVSOR, in which the axis of the monochromatized beam is unchanged for the wavelength scanning. Two gratings are interchangeable in vacuum. The designed useful region is 20–200 A(ring) with a 2400/mm grating, but the actual useful region was 50–200 A(ring). At 100 A(ring), 1010/s output photons were obtained with a resolution of 10−3. The horizontal width of the beam at the sample position was about 5 mm, while the vertical width was between 0.5 and 3 mm.

Electronic Resource

1089-7623

AIP Digital Archive

Physics

Electrical Engineering, Measurement and Control Technology

A new plane-grating monochromator and calibration chamber were constructed for the radiometric calibration of plasma diagnostic devices. The monochromator is designed to cover a wavelength range of 1.8–238 nm with moderate resolving power of 500±200 in λ/Δλ. To check the performance of the monochromator, spectral distribution and resolution were measured by experiments on photoemission from solids and photoionization of rare gases. The characterization of multilayer reflectors by the use of this beamline is demonstrated.

Electronic Resource

1077-3118

AIP Digital Archive

Physics

The current-voltage characteristic has been measured for a probe/Langmuir–Blodgett (LB) film/metal structure with the scanning tunneling microscope (STM). The rapid increase of current and substantial increase in conductance have been found when a critical positive voltage was applied to the probe. A bright spot in the STM image has been observed at the position where the increase in the conductance occurred. The changes in the STM images are attributed to the change in the conductance of LB films themselves rather than the surface topography, and may be associated with the switching phenomena in LB films.

Electronic Resource