Raman and Fourier transform infrared study of phytol effects on saturated and unsaturated lipid multibilayers
Bibliographic record
Abstract
Abstract The effects of phytol on DPPC and OPPC multilayers were investigated using FT‐IR and Raman spectroscopy. The results were compared with those obtained with α‐tocopherol (α‐T) and α‐tocopherol acetate (α‐TA). The chain packing was analyzed using Raman intensity ratios measured in the CH 2 stretching region, whereas the number of gauche bonds introduced by phytol was estimated by the measure of the FT‐IR absorbance of the CH 2 wagging progression modes. It is shown that the chain packing is reduced and that gauche rotamer formation is promoted by phytol in the gel phase. Phytol has a very similar effect on the acyl chains of DPPC to α‐T but does not have the same impact on the CO stretching vibrations of this lipid. The results indicate that phytol perturbs the interfacial region of DPPC causing dehydration or a conformational modification of the ester groups. Furthermore, the modification of the OPPC chain order induced by phytol is slightly different with respect to α‐T. It is concluded that (1) a hydrogen bond between the hydroxyl group of α‐T and the phospholipid carbonyl groups may not necessarily be associated with the stabilization of the membrane, (2) the studied phytyl compounds may be located more or less close to the membrane interface, (3) the presence of the chromanol ring may strongly influence the location of vitamin E within the membrane and, consequently, its capacity to catch free radicals and (4) the hydroxyl group, chroman moiety and phytyl chain all play a crucial role that determines the effects of α‐T on lipid acyl chains and its location within membranes, which in turn can affect its biological function. Copyright © 2002 John Wiley & Sons, Ltd.
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 | 0.000 |
| 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".