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

2018-01-26

Institute of Physics (IOP)

1757-8981

1757-899X

Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics

2015-01-28

Nature Publishing Group (NPG)

0028-0836

1476-4687

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

Biocatalysis ; Carbon Monoxide/metabolism ; Catalytic Domain ; Crystallography, X-Ray ; Cysteine/chemistry/metabolism ; Desulfovibrio vulgaris/*enzymology ; Hydrogen/*analysis/*chemistry ; Hydrogen Bonding ; Hydrogenase/*chemistry/metabolism ; Iron/chemistry/metabolism ; Ligands ; Models, Molecular ; Molecular Weight ; Nickel/chemistry/metabolism ; Protons ; Sulfur/metabolism

2015-02-14

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 ; Claudins/*chemistry ; Enterotoxins/*chemistry ; Hydrophobic and Hydrophilic Interactions ; Mice ; Protein Structure, Secondary ; Tight Junctions/chemistry/*ultrastructure

2018-12-01

American Association for the Advancement of Science (AAAS)

2375-2548

Natural Sciences in General

2014-11-02

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 ; Biodiversity ; *Chytridiomycota ; Communicable Diseases, Emerging/microbiology/*veterinary ; *Endangered Species ; Mycoses/microbiology/*veterinary ; Phylogeny ; Urodela/classification/*microbiology

1089-7674

AIP Digital Archive

Physics

Two-dimensional simulations of the electron-beam plasma instability with large system size are carried out and are compared with recent one-dimensional simulations for plasma parameters appropriate to the electron foreshock. It is found that wave propagation and diffusion perpendicular to the beam drift are significant at all times. Because a plateau cannot be maintained in this case, the wave level decreases much more rapidly than in one-dimensional simulations. The nonlinear wave scattering process which occurs at late times also differs in that it generates a broad secondary spectrum rather than a condensate. The two-dimensional model, in addition, allows the investigation of the effects of increasing magnetic field strength (e.g., along auroral field lines). For intermediate magnetic fields Langmuir waves and a highly oblique spectrum belonging to the lower hybrid branch are simultaneously excited. The oblique wave spectrum for strong magnetic fields can be explained by mapping from the magnetic field direction.

Electronic Resource

1089-7674

AIP Digital Archive

Physics

The coalescence of two parallel current loops in an electron–positron plasma is investigated by a three-dimensional electromagnetic relativistic particle code. Instead of mixing uniformly in the dissipation region as observed for current coalescence in an electron–ion plasma, electrons and positrons initially in the loops are driven to move separately by the magnetic gradient drift. Redistribution of the current-carrying electrons and positrons creates new current loops, which coalesce again, if the initial drift velocities remain greater than a critical value after coalescence. It was found that the energy stored in the current loops dissipates gradually through several coalescences. Consequently, the electrons and positrons near the current loops are heated through the coalescence. This process is qualitatively different from the explosive energy release during coalescence in an electron–ion plasma. © 1996 American Institute of Physics.

Electronic Resource

1089-7674

AIP Digital Archive

Physics

Power partition and energy dissipation rates are examined for a self-sustained stationary turbulence of a high-n ballooning mode in a tokamak plasma. It is found that the power to excite fluctuations is almost equally transferred to perpendicular ion motion and to parallel electron motion. The ratio of the thermalized power, which excites and sustains the turbulence, to the total power lost by energy diffusion is found to be of the order of the broken symmetry parameter, i.e., the inverse aspect ratio, a/R. The dissipation rates of the fluctuations due to the thermal conductivity, the electron viscosity, and the ion viscosity are also calculated separately. The dissipation is dominated by that associated with the thermal conductivity. The relation between the induced global flux and the microscopic dissipation is also derived. It is found that a fractional part of order a/R of the dissipated power is effective in sustaining the turbulent modes.

Electronic Resource

1089-7674

AIP Digital Archive

Physics

Results from three-dimensional electromagnetic particle simulations of an electron–positron plasma with a relativistic electron beam (γ=2) are presented. As part of the initial conditions, a poloidal magnetic field is specified, consistent with the current carried by the beam electrons. The beam undergoes pinching oscillations due to the pressure imbalance. A transverse two-stream instability is excited with large helical perturbations. In the process, background electrons and positrons are heated and accelerated up to relativistic energy levels. Only background electrons are accelerated farther along the z direction due the synergetic effects by both the damped transverse mode and the accompanying electrostatic waves caused by the breakdown of the helical perturbations. © 1994 American Institute of Physics.

Electronic Resource

1089-7674

AIP Digital Archive

Physics

Results from three-dimensional (3-D) electromagnetic particle simulations of Alfvén waves generated by an electron beam in a nonrelativistic electron–positron plasma are presented. The results show that electrostatic modes are excited due to the beam instability. The bunches of the particles (electrons and positrons) caused by electrostatic waves are directly involved in the generation of Alfvén waves. The Alfvén waves propagate along the beam as damped solitons accelerating the background particles. The simulation results are in good agreement with theoretical analysis.

Electronic Resource

1540-8183

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

This article presents the first case of fatal pericardial tamponade following immediately after- successful percutaneous balloon mitral commissurotonry by the Inoue balloon. The patient had a large right atrium associated with severe tricuspid regurgitation and this led to incorrect atrial puncture (so culled stitching phenomenon) under the Inoue method fir determining the site of fossa ovalis. (J lnterven Cardiol 1994; 7:33–37)

Electronic Resource

1089-7666

AIP Digital Archive

Physics

Ion-cyclotron turbulence has been observed with shocks and double layers in the magnetosphere where strongly localized electric fields perpendicular to the magnetic field are present. Theoretical analysis suggests that electrostatic waves with frequencies of the order of the ion-cyclotron frequency can be destabilized as a result of the coupling of regions of positive and negative-energy ion waves. The nonlocal theory for a smooth profile of transverse inhomogeneous electric fields shows that localized ion waves grow in the region where the electric fields are present. Using a spatially two-dimensional electrostatic code, we investigate this instability in plasma conditions characterized by a localized transverse electric field L(very-much-less-than)Lx, where Lx is the simulation length in the x direction; and distinguish it from the transverse kinetic Kelvin–Helmholtz instability. The simulation results show that the growing ion waves are associated with the small vortices in the linear state, which evolve into a nonlinear stage dominated by large vortices with lower frequencies.

Electronic Resource

1365-2044

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

We investigated changes in left ventricular mechanical performance in 40 patients aged 〉 70 years in whom anaesthesia had been induced with sevoflurane or with fentanyl and propofol. The ratio of ventricular contractility to arterial properties, which reflects left ventricular performance, was estimated from the ratio of ventricular end-systolic elastance to effective arterial elastance. This ratio decreased after induction in both groups, the magnitude of the decrease being significantly greater in the fentanyl/propofol group than in the sevoflurane group. Decreases in mean arterial pressure after induction of anaesthesia in the two groups were similar, whereas the magnitude of the decrease in heart rate in the sevoflurane group was greater than that in the fentanyl/propofol group. Sevoflurane may therefore be preferable to fentanyl and propofol for induction of anaesthesia in elderly patients because of its lesser effect on left ventricular performance.

Electronic Resource

1089-7623

AIP Digital Archive

Physics

Electrical Engineering, Measurement and Control Technology

A pressure-resisting cell system has been developed for high-pressure high-resolution nuclear magnetic resonance (NMR) measurements up to a maximum pressure of 600 MPa. This cell system is capable of performing high-pressure experiments with any standard spectrometer, including modern high field NMR machines. A full description of the high-pressure NMR assembly mounted on a 750 MHz spectrometer is presented along with a detailed explanation of the procedure for preparing the pressure-resisting quartz and glass cells. © 2001 American Institute of Physics.

Electronic Resource

1089-7690

AIP Digital Archive

Physics

Chemistry and Pharmacology

Ordered phases such as CDW, SDW, and the singlet superconductivity(SSC) are predicted by means of a mean field theory. The electronic Hamiltonian is linearized by introducing order parameters which are expected to arise, and these order parameters are determined self-consistently. The behaviors of gap, transition temperature, and condensation energy are greatly different from those of BCS theory. The coexistence of the various phases is discussed. Aside from a very special case the single phase is most stable.

Electronic Resource

1089-7690

AIP Digital Archive

Physics

Chemistry and Pharmacology

The instabilities of a normal molecular orbital state of polyacenic materials are studied within RPA with a g model for an electronic interaction. The condensed states predicted are singlet superconducting (SSC), charge density wave (CDW), and spin density wave (SDW) ones, and their phase diagram is shown. In contrast to usual one-dimensional (1D) conductors, there reveals a wide range of superconducting state, which is not overcome by CDW transition. Weakness of Peierls distortion of the present model is also contrasted with the case of polyacetylene.

Electronic Resource

1365-2516

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

It has been found that almost all haemophiliacs treated with pooled concentrates of clotting factor VIII or IX before 1985/6 have been infected with hepatitis C virus (HCV). In order to clarify the characteristics of HCV infection in Japanese haemophiliacs, we investigated the HCV genotype and HCV-RNA level in 80 patients with haemophilia who had been confirmed to be positive by a second-generation HCV antibody test. HCV-RNA was detected in 60 (75.0%) individuals and various HCV genotypes were found. Although 80% (48/60) of the patients had genotype 1b, the frequency of each genotype was quite different from that in HCV-infected non haemophiliac Japanese. Particularly, multiple HCV genotypes were observed in 27 (46.7%) patients. The mean (± SD) level of HCV-RNA was 5.3 × 105 ±  1.1 × 106 copies mL−1. The viral load in patients with genotype 2a was significantly less common than those with genotype 1a (P= 0.0007), genotype 1b (P= 0.0009) and combined genotype 1a/1b (P= 0.0019). In patients co-infected with human immunodeficiency virus (HIV), the HCV-RNA level was significantly higher (P= 0.05) than in those without co-infection. However, there was no significant difference (P= 0.25) in the HCV-RNA level with HCV/HIV co-infection among the 40 patients with group 1 genotypes. We conclude that this biased distribution of HCV genotypes in Japanese haemophiliacs reflects their specific mode of HCV infection. Moreover, these results suggest that super-infection with HIV does not greatly influence the HCV load in patients with no marked immunological deterioration.

Electronic Resource

1365-2044

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

We report a case of concealed Wolff-Parkinson-White syndrome detected for the first time during spinal anaesthesia in an adult male. Episodes of tachy'arrhythmia with a heart rate of approximately 115 beat.min−1, wide QRS complexes and negative T waves which lasted 30–60 s, but were unassociated with hypotension, occurred three times after spinal anaesthesia. Postoperative Holler ECG monitoring showed the frequent occurrence of supraventricular premature contractions and paroxysmal supraventricular tachycardias with the same electrophysiological characteristics as those noted during spinal anaesthesia. The patient was diagnosed as having concealed Wolff-Parkinson-White syndrome. Since this condition is asymptomatic and undetectable by routine pre-operative screening it is likely that other unsuspected cases will arise. When episodes of tachyarrhythmia occur unexpectedly during anaesthesia, as was the case in this patient, postoperative examination including Holler ECG monitoring will be necessary to determine the nature and severity of the tachyarrhythmia.

Electronic Resource

1440-1797

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Electronic Resource

1440-1797

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Electronic Resource