Reexamination of the Elastic Properties of Emphysematous Lungs
Bibliographic record
Abstract
We calculated specific lung elastance (Es,L) as the change of lung elastic recoil pressure (Pel,L) required to produce a given fractional change in lung volume (delta VL/VL,0) as a function of transpulmonary pressure (PL) from published data in normal lungs, and in patients with chronic obstructive pulmonary disease (COPD) or alpha 1-antitrypsin deficiency (alpha 1-AD). Es,L, in normal lungs, is the bulk modulus, and was systematically greater than PL.dEs,L/dPL increased with VL.PL at Es,L = 30 cm H2O decreased with age in normal lungs, but Es,L at PL = 8 cm H2O showed no age relationship. In both COPD and alpha 1-AD Es,L and dEs,L/dPL were increased compared to normal lungs. We conclude that Es,L is a curvilinear function of PL in normal lungs, COPD and alpha 1-AD, and is systematically greater than PL. The increase in Es,L and dEs,L/dPL in COPD and alpha 1-AD compared to normals probably represents two distinct abnormalities in the elastic properties of emphysematous lungs: (1) an increase in resting length of alveolar walls accounting for hyperinflation, and (2) a decrease in extensibility of alveolar walls once they become stressed. Using total lung capacity (TLC) as an index of the former and Es,L as an index of the latter, we showed no correlation between either and FEV1. Thus abnormalities in lung elastic properties in emphysema do not account for chronic expiratory flow limitation in emphysema. Furthermore, the increased values of Es,L in emphysema suggest that emphysematous airspaces are poorly ventilated. As they are presumably poorly perfused, emphysema per se may not disturb ventilation perfusion ratios seriously.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".