Biomedical subjects

A Awazu

Publications and source records attributed to A Awazu.

10 recordsLinked to original sources

PubMed2001

Liquid-solid phase transition of a system with two particles in a rectangular box.

We study the statistical properties of two hard spheres in a two-dimensional rectangular box. In this system, a relation similar to the van der Waals equation is obtained between the width of the box and the pressure working on the sidewalls. The autocorrelation function of each particle's position is calculated numerically. This calculation shows that, near the critical width, the time at which the correlation becomes zero gets longer as the height of the box increases. Moreover, fast and slow relaxation processes such as the alpha and beta relaxations in supercooled liquids are observed when the height of the box is sufficiently large. These relaxation processes are discussed with reference to the probability distribution of the relative positions of the two particles.

Journal Article↗

PubMed2000

Size segregation and convection of granular mixtures almost completely packed in a thin rotating Box

We simulate size segregation in granular mixtures which are almost completely packed in a rotating drum. Instead of a 3D drum, we simulate a 2D thin rotating box which is almost completely packed with granular mixtures. The phase inversion of a radially segregated pattern which was found in a 3D experiment is qualitatively reproduced with this simulation. A global convection appears after a radial segregation pattern is formed, and this convection induces an axially segregated pattern.

Journal Article↗

PubMed1993

[Development and medical application of Er-YAG laser].

Result of developments of Er-YAG laser and its delivery system were reported. Er-YAG laser's wavelength is 2.94 microns, the beam absorption rate by water is higher than other laser beam. Er-YAG laser has repeated pulse oscillation, pulse width is 400 mu, sec, the repeat frequency is between 5 to 10 pulse per second. The mean power is 4 W maximum, 10 pps. The fibers of laser are made of zirconium-F-glass. We carried out a study on the possible application of the Er-YAG laser on the rabbit arteries and myocardium and human arteries were examined in vitro. Very clear cuts were observed on the histological examination. There were no evidence of thermal damage, no carbonization on the sharp cutting surface. Experimental result showed that Er-YAG lasers had good potential for angioplastic laser.

Angioplasty, Laser↗

PubMed1992

[Valve replacement in a patient with infective endocarditis and ruptured mycotic cerebral aneurysm].

A 55-year-old man with a mild fever and sweating developed severe headache for the days before admission. Cerebral computed tomography and selected cerebral angiography on the day of admission revealed subarachnoid hemorrhage due to rupture of an aneurysm of a distal branch of the left middle cerebral artery. Detection of vegetation on the aortic valve by two dimensional echocardiography confirmed the diagnosis of infective endocarditis with a ruptured mycotic cerebral aneurysm. Because of rapid growth of the vegetation on the aortic valve and progression of heart failure despite antibiotic therapy, emergency cardiac surgery was performed. To prevent re-rupture of the aneurysm, the aortic valve was replaced with a bioprosthetic valve, and no anticoagulant was administered postoperatively. Repeated cerebral angiography revealed that the aneurysm was becoming progressively smaller during the next 9 months. No cerebrovascular accident occurred postoperatively. We believe that it is safe to treat a ruptured mycotic cerebral aneurysm without involvement of a hematoma mass in the brain conservatively, and that use of a bioprosthetic valve, if valve replacement is mandatory, and avoidance of anticoagulant therapy during the postoperative period are advisable in the treatment of a patient with infective endocarditis and a ruptured cerebral mycotic aneurysm.

Aneurysm, Infected↗

PubMed1986