<i>T</i><sub>2</sub> measurement and quantification of glutamate in human brain in vivo
Bibliographic record
Abstract
The proton NMR transverse relaxation time T(2) of glutamate (Glu) in human brain was measured by means of spectrally selective refocusing at 3.0 T in vivo. An 81.4-ms-long dual-band Gaussian 180 degrees RF pulse, designed for refocusing at 2.35 and 3.03 ppm, was employed within point-resolved spectroscopy (PRESS) to generate the Glu C4-proton target multiplet and the total creatine (tCr) singlet. Six optimal echo times (TEs) between 128 and 380 ms were selected from numerical analysis of the filtering performance for effective detection of the Glu signal with minimal contamination from glutamine (Gln), N-acetylaspartate (NAA), and glutathione (GSH). The magnetization of Glu and tCr was extracted from spectral fitting of experimental and calculated spectra. Apparent T(2) values of Glu and tCr were estimated as 201 +/- 18 and 164 +/- 12 ms for the medial prefrontal (PF) cortex, and 198 +/- 22 and 169 +/- 15 ms (mean +/- SD, N = 5) for the left frontal (LF) cortex, respectively. With water segmentation data, the magnetization values of Glu and tCr of the two adjacent voxels, calculated from the T(2) values and spectra following the thermal equilibrium magnetization, were combined to give the Glu and tCr concentrations as 10.37 +/- 1.06 and 8.87 +/- 0.56 mM for gray matter (GM), and 5.06 +/- 0.57 and 5.16 +/- 0.45 mM (mean +/- SD, N = 5) for white matter (WM), respectively.
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How this classification was reachedexpand
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) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| 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) | 0.000 | 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 itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, 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".