Primary Steps in the Reaction of OH Radicals with Amino Acids at Low Temperatures in Laval Nozzle Expansions: Perspectives from Experiment and Theory
Why this work is in the frame
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Bibliographic record
Abstract
Recent work has focused on the damaging effects of free radicals on biological molecules. This study investigates the kinetics of the attack of OH radicals on L-alanine ethyl ester in the gas phase in cold beams of Laval nozzle expansions. Experiments and high-level theory are used to understand the preferred site of attack by the OH radical. Optimizations of L-alanine and L-alanine ethyl ester show that the essential transition state features for hydrogen abstraction off the C(alpha), C(beta), and N are similar. The energetics show that for L-alanine, the C(alpha)-site, C(beta)-site, and N-site transition states are all below the reactants level. For L-alanine ethyl ester, however, the energetics for hydrogen abstraction off the C(alpha) and N are the preferred site of reaction. These findings are supported by the observed negative temperature dependence of the rate constants of OH with alanine ethyl ester in Laval nozzle expansion experiments. More importantly, both the experiments and theory show that L-alanine ethyl ester provides a good model for gas phase studies of the amino acids such as L-alanine.
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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 | 0.000 | 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) | 0.000 | 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