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Biomedical subjects

Y Seki

Publications and source records attributed to Y Seki.

277 records · Page 16Linked to original sources
PubMedDate not supplied

Presence of two subcomponents in P9 far-field potential following stimulation of the median nerve.

Close scrutiny of scalp recorded P9 far-field potentials following stimulation of the median nerve often revealed dilobed wave forms. We observed that the P9 became 2 distinct peaks (P9a and P9b) when the arm was flexed 90 degrees forward at the shoulder and that it became a pointed single peak with 90-170 degrees lateral abduction of the arm. A simultaneously recorded stationary negative peak (N9), registered over the stimulated arm with the use of a distant reference, also showed similar changes, a dilobed configuration (N9a and N9b) with forward flexion and a single peak with lateral abduction. The latencies of the scalp recorded P9a and P9b and arm recorded N9a and N9b were close but not exactly the same. Nevertheless, the latencies of the scalp-positive and arm-negative peaks shifted in nearly a parallel fashion by changing the arm positions. These findings suggest that the change of axial orientation of the propagating nerve impulse plays an important role for the rise of P9a and that the change of volume geometry surrounding the nerve contributes to the P9b generation. Also, the scalp recorded P9 and arm recorded N9 are one and the same, and oriented with dipole fields extending from the arm, body and to the scalp.

Action Potentials↗
PubMedDate not supplied

A simple method for detecting breakthroughs in used chemical cartridges.

This study was intended to develop a simple method using a gas detector tube to detect the end of the service lives of chemical cartridges for organic solvent vapors. The practical usefulness of this method was confirmed by two series of experimental observations of cartridge service lives: (1) The breakthrough times for six organic solvents were determined by passing a test airflow through a cartridge, and the concentration at each breakthrough was measured with a gas chromatograph (GC). These GC-obtained concentrations were compared with the migrated vapor concentrations through each broken cartridge measured with a gas detector tube. (2) CS2 breakthrough of the cartridges used on 32 viscose rayon workers were measured with detector tubes, after which the residual service life of each cartridge was determined. In laboratory experiments the released concentrations detected by the gas detector tube were approximately equal to the final leak concentrations measured by GC. In a field survey the used cartridges exhibiting a stain of CS2 from detector tubes for concentrations greater than 4 ppm were found not to have enough residual adsorption capacity for CS2. Migrated concentrations of CS2 measured with detector tubes were found to be a reasonable predictor of remaining service life.

Air Pollutants, Occupational↗
PubMedDate not supplied

Aneurysm arising from the petrous portion of the internal carotid artery: case report.

A 21-year-old man with hearing loss and recurrent otorrhagia was shown angiographically to have an aneurysm arising from the intrapetrous internal carotid artery (ICA). Endovascular balloon occlusion of the aneurysm with preservation of the parent ICA was attempted twice, but each time the balloon deflated and the aneurysm reappeared two weeks and three months, respectively, following the endovascular procedures. The patient was then successfully treated with a surgical trapping procedure combined with superficial temporal artery-middle cerebral artery bypass.

Adult↗