Age‐associated change in pyruvate metabolism investigated with hyperpolarized <scp><sup>13</sup>C‐MRI</scp> of the human brain
Bibliographic record
Abstract
Abstract In this study, hyperpolarized 13 C MRI (HP‐ 13 C MRI) was used to investigate changes in the uptake and metabolism of pyruvate with age. Hyperpolarized 13 C‐pyruvate was administered to healthy aging individuals ( N = 35, ages 21–77) and whole‐brain spatial distributions of 13 C‐lactate and 13 C‐bicarbonate production were measured. Linear mixed‐effects regressions were performed to compute the regional percentage change per decade, showing a significant reduction in both normalized 13 C‐lactate and normalized 13 C‐bicarbonate production with age: per decade for 13 C‐lactate and per decade for 13 C‐bicarbonate. Certain regions, such as the right medial precentral gyrus, showed greater rates of change while the left caudate nucleus had a flat 13 C‐lactate versus age and a slightly increasing 13 C‐bicarbonate versus age. The results show that both the production of lactate (visible as 13 C‐lactate signal) as well as the consumption of monocarboxylates to make acetyl‐CoA (visible as 13 C‐bicarbonate signal) decrease with age and that the rate of change varies by brain region.
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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 | 0.000 |
| 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".