Poly(<i>para</i>-phenylene ethynylene)s functionalized with Gd(III) chelates as potential MRI contrast agents
Bibliographic record
Abstract
A poly(para-phenylene ethynylene) with water-solubilizing groups and Gd(III) chelates conjugated to the polymer backbone was designed and synthesized. Pre- and post-polymerization functionalization approaches were explored and the pre-polymerization approach for the introduction of the Gd(III) chelate was found to be more successful. The UV–vis absorption and fluorescence emission properties of the protected polymers were characterized and were found to be consistent with the results expected for this class of polymers. Removal of the protecting groups followed by chelation of Gd(III) led to a water-dispersible polymer. Relaxivity measurements were performed on this polymer with the aim of evaluating its potential as a new MRI contrast agent, and an r1 of 1.37 L mmol–1 s–1 at 310 K and 20 MHz was determined. These results, along with dynamic light scattering analyses, suggested that the polymers formed micrometre-sized assemblies in aqueous solution. Although the relaxivity was relatively modest, these results provide important insights into the assembly properties of this new class of polymers and into the design criteria for future agents.
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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".