Morphological and mechanical examination of the atrial 'intima'
Bibliographic record
Abstract
AIMS: To examine morphology and mechanical properties of the atrial 'intima', which we defined as the tissue interposed between atrial endocardium and myocardium, in patients without known cardiovascular disease. METHODS AND RESULTS: Post-mortem right and left atrial tissue was obtained from male infants (<1 year, n = 4), children (10-19 years, n = 4), and adults (58-69 years, n = 7). Using light microscopy and an ocular micrometer, atrial intimal (AIT) thickness was measured. Intimal collagen bundle thickness was measured using electron microscopy. Passive atrial wall stiffness was measured using a planar biaxial testing device. Among infants, left AIT (0.2 ± 0.2 mm) and right (0.2 ± 0.1 mm) AIT were not significantly different (P = 0.84). Among children, left AIT (0.6 ± 0.2 mm) was significantly greater than right (0.2 ± 0.1 mm) AIT (P = 0.03), and left AIT was marginally greater than in infants (P = 0.07). Among adults, with the exception of the appendage region, left AIT (1.0 ± 0.2 mm) was markedly greater than right AIT (0.3 ± 0.1 mm; P < 0.05), and left AIT was significantly greater than that in other age groups (P < 0.05). There were no differences in right AIT among age groups. Left intimal collagen bundle thickness was greater in adults (0.0512 ± 0.0056 µm) than infants (0.0432 ± 0.0071 µm) or children (0.0435 ± 0.0013 µm), and bundles were less organized. Wall stiffness was attributable primarily to the intima (1245 ± 132, vs. 260 ± 45 N/m(2) for the remaining atrial wall). CONCLUSION: The left atrial intima, but not the right, thickens with age, becomes more disorganized ultrastructurally, and is responsible for the majority of atrial wall stiffness.
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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 | 0.000 | 0.001 |
| 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 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| 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".