Detection of Pyridine Derivatives by SABRE Hyperpolarization at Zero Field
Bibliographic record
Abstract
Zero-field nuclear magnetic resonance (NMR) recently emerged as an interesting new analytical modality. While zero-field NMR provides new capabilities, it also suffers from some limitations associated, to a great degree, with low signal amplitude. In this context, parahydrogen-induced polarization naturally complements zero-field NMR, as this hyperpolarization is active even at zero magnetic field. In turn, the efficient production of large non-equilibrium polarization is possible in zero field, boosting the signal amplitude and enabling realization of the concept of "NMR without magnets''. In this work, we present zero-field NMR studies of various hyperpolarized pyridine derivatives where the 15N isotope is present at a natural abundance (0.36%). By comparing the signals of these pyridine derivatives, which include vitamin B3, as a function of their substituents, we demonstrate unique zero-field NMR spectra, consequently establishing how chemical analysis is possible even in zero field. We also study the effect of the parahydrogen-polarization-transfer catalyst activation on the resulting hyperpolarization dynamics. All of these measurements were made using apparatus designed to allow repeated in situ hyperpolarization of these samples without affecting their composition.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.000 | 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 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 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".