Bibliographic record
Abstract
The molar absorption coefficient of pyrene aggregates, epsilon(E0), was determined for a series of pyrene-labeled poly(N,N-dimethylacrylamide)s (Py-PDMA) having different pyrene contents. Aqueous solutions of Py-PDMA having pyrene contents ranging from 263 to 645 mumol of pyrene per gram of polymer were studied by UV-vis absorbance and time-resolved fluorescence spectroscopy. The global analysis of the monomer and excimer fluorescence decays with the fluorescence blob model yielded the fractions of the overall absorption contributed by all the pyrene species present in solution. The combined knowledge of the fractions obtained from the global analysis of the time-resolved fluorescence decays, the total absorption of the Py-PDMA solution obtained from UV-vis spectroscopy, and the total pyrene concentration in the solution obtained from the known pyrene content of each Py-PDMA sample led to the determination of the molar absorption coefficient of pyrene aggregates. Regardless of the pyrene content of the Py-PDMA samples and hence the level of association of the pyrene pendants in solution, all Py-PDMA samples yielded similar epsilon(E0) values over the range of wavelengths studied, namely, from 325 to 350 nm. The averaged epsilon(E0) was found to be red-shifted relative to unassociated pyrenes by 3 nm as well as having a value at the 0-0 peak of 21 000 M(-1).cm(-1) reduced from 34 700 M(-1).cm(-1) for unassociated pyrenes. The determination of epsilon(E0) enabled the first determination of the absolute fraction of associated pyrenes for aqueous solutions of a series of pyrene-labeled water-soluble polymers. The procedure outlined in this study is applicable to any pyrene-labeled water-soluble polymer and provides a new means to study quantitatively the effect of the hydrophilic-to-lipophilic balance on the hydrophobic associations generated by hydrophobically modified water-soluble polymers. As an application, the average number of pyrenes involved in a pyrene aggregate generated by Py-PDMA in water is determined.
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 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 | 0.001 |
| 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 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 0.001 |
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".