Enzyme-induced biodegradation of polycarbonate polyurethanes: Dependence on hard-segment concentration
Bibliographic record
Abstract
Polycarbonate-based polyurethanes with varying hard segment contents were synthesized. The physical and chemical structures were characterized by using gel permeation chromatography, differential scanning calorimetry, water uptake testing, Fourier transform infrared, and attenuated total reflectance--Fourier transform infrared. The polymers were incubated with cholesterol esterase in a phosphate buffer solution at 37 degrees C over 10 weeks. A higher resistance to hydrolytic degradation was observed in polycarbonate-based urethanes with higher hard segment content. The analysis of the material structures revealed that the degradation of polycarbonate-based urethanes was preferentially initiated at non-hydrogen-bonded carbonates and urethanes. Although the crystallinity of the polycarbonate soft segment may contribute to reducing the hydrolytic degradation catalyzed by cholesterol esterase, it was found to be relatively minor in comparison to the importance of hydrogen bonding between the carbonate and urethane groups. These observations suggest that the biostability of polyurethanes and specifically polycarbonate-based polyurethanes can be improved by manipulating the degree of hydrogen bonding within the materials.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 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".