In vitro ultrasound characterization of coronary arteries at 50 MHz
Bibliographic record
Abstract
Ultrasonic attenuation coefficient, wave speed and integrated backscattering coefficient (IBC) of human coronary arteries were evaluated, in vitro, over the -6 dB frequency bandwidth of 35-68 MHz, for a total of 44 artery samples (normal and diseased). The wave speed measurements (average over the entire vessel wall thickness) varied from 1507 to 1746 m/s with a population mean (/spl plusmn/ one standard deviation) of 1575.92 (/spl plusmn/52.29) m/s. At 50 MHz the attenuation coefficient, 5.08 (/spl plusmn/1.31) dB/mm, varied between 3.0 and 8.6 dB/mm. Over the frequency range of 35-68 MHz, the frequency exponent of the attenuation coefficient, 1.53 (/spl plusmn/0.18), varied between 1.11 and 1.88. IBC results for the media layers are within 2.0/spl times/10/sup -3/ and 8.0/spl times/10/sup -3/ (Sr/spl middot/mm)/sup -1/, while those for intima and adventitia fall between 10/sup -2/ and 10/sup -1/ (Sr/spl middot/mm)/sup -1/. Plots of IBC as a function of depth show the potential for using IBC to differentiate between normal and diseased vessel walls.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 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".