[Characteristics of F-V curve configuration and its tangent time constants and its wave-speed mechanism in normal humans above 50 years old].
To understand the characteristics of F-V curve configuration and its tangent time constant (tau 1) in normal humans above 50 years old, the tau 1 at high, mid, low lung volumes (tau 175, tau 150, tau 125) were measured from F-V curves for 135 normal humans aged 50-84. The results showed that the convex type was the most frequent one (40%-75%) among the 4 types of F-V curve and its tau 1 characteristics were tau 175 > tau 150 < tau 125 and magnitude of tau 175 < 1s; on the other hand, the concave type was the least frequent one (0.18%). These suggested that the convex type and its tau 1 characteristics might be the changes in senility. Further, the mechanical mechanism for the convex type of F-V curve configuration was explored.
Huang
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Sun
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Huang
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D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D001696:Biomechanical Phenomena; D005260:Female; D006801:Humans; D008168:Lung / Q000503:physiopathology*; D008297:Male; D008449:Maximal Expiratory Flow-Volume Curves; D008875:Middle Aged