Comparison of the effects of independently‐controlled end‐tidal PCO<sub>2</sub> and PO<sub>2</sub> on blood oxygen level–dependent (BOLD) MRI
Why this work is in the frame
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Bibliographic record
Abstract
PURPOSE: To assess the effect of changes in end-tidal partial pressure of O(2) (PETO(2)) on cerebrovascular reactivity (CVR) estimated from changes in blood oxygen level-dependent (BOLD) signal during cyclic changes in end-tidal partial pressure of CO(2) (PETCO(2)). MATERIALS AND METHODS: BOLD response to fixed cyclic step changes in PETCO(2) (range = 30.4-48.8 mmHg) and PETO(2) (range = 100.6-444.0 mmHg) was studied in four healthy volunteers. RESULTS: The BOLD reactivity to PETCO(2) and PETO(2) were 0.283 (0.188-0.379) (median, range) and 0.004 (0.003-0.006)%/mmHg, respectively, in the whole brain; 0.438 (0.382-0.614) vs. 0.006 (0.004-0.009)%/mmHg, respectively, in the gray matter; and 0.075 (0.065-0.093) vs. 0.002 (0.001-0.002)%/mmHg, respectively, in the white matter. CONCLUSION: The BOLD reactivity to PETO(2) was much smaller than that to PETCO(2). However, BOLD reactivity can be significantly distorted by CO(2)-induced changes in PETO(2). We conclude that PETO(2) should be carefully controlled during studies that use BOLD reactivity as an indicator of CVR.
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Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 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 | 0.001 |
| Insufficient payload (model declined to judge) | 0.000 | 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 it