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J Tani

Publications and source records attributed to J Tani.

36 records · Page 2Linked to original sources
PubMed1982

Peribronchial stress analysis utilizing concentric cylindrical shells of parenchyma.

The mechanical dependence of bronchial volume on parenchymal properties and on intrabronchial and pleural pressures was investigated utilizing finite elasticity theory. Treating the lung parenchyma as a compressible continuum, and using a simple strain-energy-density function fitted to pressure-volume curves of saline-filled lungs, we analyzed nonhomogeneous large deformations of the fluid-filled excised dog lobe by numerical procedures. For the purpose of obtaining peribronchial stress distributions, the lung was represented by a hollow very thick-walled cylinder corresponding to an axial bronchus with surrounding parenchyma. Finite elements consisted of concentric cylindrical shells. In general, we found that the theoretical results corresponded well to published stress and strain data for bronchial collapse. Peribronchial radial and circumferential stresses were found to be concentrated at the bronchial wall, but dissipated rapidly with 1-2 bronchial radii away from the wall. We conclude that the magnitude of regional lung recoil around bronchi during collapse can be reasonably well estimated by a theoretical analysis based on total lung pressure-volume relationships.

Airway Resistance↗
PubMed1982

Mechanical behavior of lung parenchyma as a compressible continuum: a theoretical analysis.

The mechanical behavior of bronchial volume with respect to parenchymal properties, and to both the intrabronchial and pleural pressure, was investigated utilizing a theory of finite elasticity. Treating the lung parenchyma as a compressible continuum, we derived a simple strain-energy density function from pressure-volume curves of saline-filled lungs. On the basis of this function, large deformations of the fluid-filled excised dog lobe could be analyzed by numerical procedures. For the purpose of obtaining peribronchial stress, the lung was represented by a hollow thick-walled cylinder corresponding to an axial bronchus with surrounding parenchyma. In general, we found that the theoretical results corresponded well to previous experimental results, being able to predict quantitatively the stress and strain around the bronchus during collapse previously demonstrated by Nakamura et al. Peribronchial radial and circumferential stresses were shown to be concentrated at the bronchial wall, but dissipated rapidly within 1-2 bronchial radii away from the wall. We conclude that the magnitude of regional lung recoil around bronchi during collapse can be plausibly estimated by a theoretical analysis of total lung pressure-volume relationships.

Animals↗
PubMed1979

Studies on biologically active halogenated compounds. 1. Synthesis and central nervous system depressant activity of 2-(fluoromethyl)-3-aryl-4(3H)-quinazolinone derivatives.

Some 2-(fluoromethyl) analogues of 2-methyl-3-aryl-4-(3H)-quinazolinones have been synthesized and screened for CNS activities. It was shown that the 2-(fluoromethyl) analogues possess in general more potent CNS depressant activities and less toxicities than their parent compounds. Of particular interest were the 2-(fluoromethyl) analogues (22, 24, and 31) of methaqualone and 6-aminomethaqualone. Compound 24 was more potent in CNS depressant activity and less toxic than methaqualone. Compound 31 exhbited potent central muscle relaxing activity and markedly reduced toxicity as compared with 6-aminomethaqualone.

Animals↗