Effect of inhaled oxygen concentration on <sup>129</sup>Xe chemical shift of red blood cells in rat lungs
Bibliographic record
Abstract
Purpose To investigate the dependence of dissolved 129Xe chemical shift on the fraction of inhaled oxygen, FiO2, in the lungs of healthy rats. Methods The chemical shifts of 129Xe dissolved in red blood cells, δRBC, and blood plasma and/or tissue, δPlasma, were measured using MRS in 12 Sprague Dawley rats mechanically ventilated at FiO2 values of 0.14, 0.19, and 0.22. Regional effects on the chemical shifts were controlled using a chemical shift saturation recovery sequence with a fixed delay time. MRS was also performed at an FiCO2 value of 0.085 to investigate the potential effect of the vascular response on δRBC and δPlasma. Results δRBC increased with decreasing FiO2 (P = .0002), and δPlasma showed no dependence on FiO2 (P = .23). δRBC at FiCO2 = 0 (210.7 ppm ± 0.1) and at FiCO2 = 0.085 (210.6 ppm ± 0.2) were not significantly different (P = .67). δPlasma at FiCO2 = 0 (196.9 ppm ± 0.3) and at FiCO2 = 0.085 (197.0 ppm ± 0.1) were also not significantly different (P = .81). Conclusion Rat lung δRBC showed an inverse relationship to FiO2, opposite to the relationship previously demonstrated for in vitro human blood. Rat lung δRBC did not depend on FiCO2.
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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 | 0.000 |
| 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 | 0.001 |
| 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".