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Biomedical subjects

M Sasao

Publications and source records attributed to M Sasao.

At least 19 recordsLinked to original sources
PubMed2003

Sawtooth oscillation in current-carrying plasma in the large helical device.

Sawtooth oscillations have been observed in current-carrying helical plasmas by using electron-cyclotron-emission diagnostics in the Large Helical Device. The plasma current, which is driven by neutral beam injection, reduces the beta threshold of the sawtooth oscillation. When the central q value is increased due to the plasma current, the core region crashes, and, when it is decreased, the edge region crashes annularly. Observed rapid mixture of the plasma in the limited region suggests that these sawtooth crashes are reconnection phenomena. Unlike previous experiments, no precursor oscillation has been observed.

Journal Article↗
PubMed2002

Island dynamics in the large-helical-device plasmas.

In the Large Helical Device plasma discharges, the size of an externally imposed island with mode number ( n/m = 1/1) decreases substantially when the plasma is collisionless ( nu(*)< approximately 1) and the beta is finite ( > approximately 0.1%) at the island location. For the collisional plasmas with finite beta, on the other hand, the size of the island increases. However, there is a threshold in terms of the vacuum island size below which the island enlargement is not seen.

Journal Article↗
PubMed2001

Observation of the "self-healing" of an error field island in the large helical device.

It was observed that the vacuum magnetic island produced by an external error magnetic field in the large helical device shrank in the presence of plasma. This was evidenced by the disappearance of flat regions in the electron temperature profile obtained by Thomson scattering. This island behavior depended on the magnetic configuration in which the plasmas were produced.

Journal Article↗
PubMed2001

Reduction of ion thermal diffusivity associated with the transition of the radial electric field in neutral-beam-heated plasmas in the large helical device.

Recent large helical device experiments revealed that the transition from ion root to electron root occurred for the first time in neutral-beam-heated discharges, where no nonthermal electrons exist. The measured values of the radial electric field were found to be in qualitative agreement with those estimated by neoclassical theory. A clear reduction of ion thermal diffusivity was observed after the mode transition from ion root to electron root as predicted by neoclassical theory when the neoclassical ion loss is more dominant than the anomalous ion loss.

Journal Article↗
PubMed2001

Plasma perturbation induced by laser photodetachment.

The plasma dynamics arising from laser photodetachment is discussed herein theoretically and experimentally. The hybrid fluid-kinetic model, where the positive ions and electrons are treated by the fluid theory and the negative ions are treated within the ballistic approximation, is extended and applied to the analysis of densities perturbed by laser photodetachment. The agreement between the theory and measured data confirms the validity of the considered plasma dynamics model. This model, including the positive ion perturbation, shows a good agreement with the time evolution and the spatial distribution of perturbed electron densities which are measured by a Langmuir probe inside and outside the laser beam. From the overshoot in the time evolution of perturbed electron current in the center of the laser beam, the positive ion temperature was found to be in the range 0.1-0.25 eV, while the electron temperature changes from 0.3 to 3.2 eV.

Journal Article↗
PubMed2000

Ion heating and high-energy-particle production by ion-cyclotron heating in the large helical device

Ion-cyclotron heating was applied to the Large Helical Device. When the proton-cyclotron resonance was near the saddle point of the magnetic field-strength plane, strong ion-cyclotron damping occurred. Under these conditions efficient plasma heating was achieved for more than one minute. A high-energy ion tail was observed, and the effective tail temperature was determined by a balance between the wave acceleration and the electron-drag relaxation. There was no apparent sign of particle orbit loss effect in the investigated density range of 0.8-1.3x10(19) m(-3).

Journal Article↗
PubMed1998

[General anesthesia in a patient with Cornelia de Lange syndrome with restricted opening of the mouth].

Patients with Cornelia de Lange syndrome have many anomalies including micrognathia with a small mouth, a high arched palate, and a short neck, which might make laryngoscopy for tracheal intubation difficult during induction of general anesthesia. General anesthesia was performed in a patient with Cornelia de Lange syndrome, and restricted opening of the mouth, which had not been reported previously, was found during laryngoscopy. The possible causes were thought to be temporo-mandibular joint disorders, contracture of the masseter muscle due to injury by self-destructive tendencies, or elogated coronoid process. The potential difficulty with laryngoscopy should be considered for tracheal intubation in a patient with Cornelia de Lange syndrome.

Adult↗
PubMed1989

Ethanol patch test--a simple and sensitive method for identifying ALDH phenotype.

The ethanol patch test, which is considered to be a cutaneous model of flushing, was performed on 311 healthy Japanese (237 adults and 74 children). By comparing the results with aldehyde dehydrogenase (ALDH) phenotype determined by isoelectric focusing from hair roots samples, it was demonstrated that the ethanol patch test is a good indicator of the ALDH phenotype. The usefulness of this test in future studies was discussed.

Adult↗
PubMed1989

An outbreak of amebiasis in an institution for the mentally retarded in Japan.

The results of an epidemiological survey in a 190-patient institution for mentally retarded were reported. Twenty percent of the patients had either cysts or trophozoites of Entamoeba histolytica in their stools, and 38% were positive serologically. The amebic outbreak revealed a sex-independent but age-dependent distribution; younger patients had more serious symptoms in cases invasive amebiasis. A high prevalence of amebic infection was found in the heavily retarded patients, and the positive cases tended to concentrate in certain training classes. Further demographic analysis suggests that the amebic infection was possibly caused by abnormal behavior of heavily retarded patients.

Adolescent↗
PubMed1987

A case of intestinal myiasis in Japan.

A case of intestinal myiasis caused by larvae of Sarcophaga peregrina (Japanese name: senchi-nikubae) is reported. The patient passed stools containing live fly larvae for 2 days, but was otherwise asymptomatic. The patient seems to have been infested accidentally as a result of having eaten "yakitori" in which the fly had deposited its larvae. This paper is the first report of intestinal myiasis caused by the 3rd instar of this species.

Adult↗