A Comparative Monolayer Film Behavior Study of Monoglucosyl Diacylglycerols Containing Linear, Methyl Iso-, and ω-Cyclohexyl Fatty Acids
Bibliographic record
Abstract
A comparative monomolecular film study of a series of 1,2-di- O -(α- d -glucopyranosyl)- sn -glycerols in which the acyl chains were 16:0, 18:0, 19:iso, and 15:ω-cyclohexyl, was carried out at the air/water interface. Area/temperature isobars were obtained in the 20° through 60 °C range with the lipids going from fully condensed to fully expanded. It was found that the area/molecule shift between the expanded and condensed states decreased in the order 16:0 and 18:0 > 19:iso > 15-ω-cyclohexyl, with the expanded state of the ω-cyclohexyl glycolipid being the most condensed. Reduction of the area/molecule shift arose through an expansion of the condensed state and a condensation of the expanded state. Isotherms of the straight-chain glycolipids showed only a small expansion on changing the pH from 5.6 to 2.0, but the ω-cyclohexyl glycolipid showed no effect. All the glycolipids studied showed thermal stability up to the 60 °C range, in contrast with previously obtained results on similar phosphatidylcholines, which were unstable above 40 °C. These results help explain the greater than 70% abundance of ω-cyclohexyl glycolipids in several strains of Bacillus acidocaldarius, whose natural environment is in hot springs with a pH as low as 3 and a temperature of up to 65 °C. It is postulated that the ability to overcome the acidity arises through the insensitivity of the polar headgroup and the highly impermeable bilayer, whereas a glycolipid headgroup appears essential for survival at high temperatures.
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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".