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Record W1965288442 · doi:10.1163/156856202320253965

Influence of surface morphology and chemistry on the enzyme catalyzed biodegradation of polycarbonate-urethanes

2002· article· en· W1965288442 on OpenAlex

Why this work is in the frame

A frame that forgets how it found something cannot be audited. These are the routes that admitted this work.

affAt least one author lists a Canadian institution in the pinned OpenAlex snapshot.

Bibliographic record

VenueJournal of Biomaterials Science Polymer Edition · 2002
Typearticle
Languageen
FieldChemistry
TopicAntimicrobial agents and applications
Canadian institutionsUniversity of Toronto
Fundersnot available
KeywordsPolycarbonateX-ray photoelectron spectroscopyPolyurethanePolymerChemical engineeringChemistryPolymer chemistryMorphology (biology)BiodegradationMaterials scienceOrganic chemistry

Abstract

fetched live from OpenAlex

Polycarbonate based polyurethanes were synthesized with varying hard segment content as well as hard segment chemistry based on three different diisocyanates,1,6-hexane diisocyanate (HDI), 4.4'-methylene bisphenyl diisocyanate (MDI) and 4,4-methylene biscyclohexyl diisocyanate (HMDI). The surface chemistry and morphology were characterized using X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). The polymers were incubated with cholesterol esterase (CE) in a phosphate buffer solution at 37 degrees C over 10 weeks. XPS results showed that the surface chemistry changed as the size and chemistry of the hard segment varied within the materials. AFM images exhibited distinctive surface morphologies for all polymers, and this was particularly apparent with changes in the hard segment chemistry. The results showed that the surface of HDI polymers consisted of relatively stiff rod-like structures, which corresponded to the soft segment domains. Polymers with a higher HDI content exhibited a dense top layer containing a relatively higher hard segment component, covering the sub-surface matrix of rod like structures. The MDI based polyurethane had large aggregates on its top surface, which corresponded to the aggregation of harder components. The HMDI based polycarbonate-urethane presented a relatively homogeneous surface where no phase separation could be detected. The relative differences in hard and soft segment content in their surface structure was supported by XPS findings. The analysis of the biodegradation results, concluded that enzyme catalyzed biodegradation within these materials was initiated in amorphous soft segment regions located in the region of the interface between hard and soft segments. A higher hard segment content at the surface contributed significantly to an increase in biostability. The findings provided an enhanced understanding for the role of surface molecular structure in the enzyme catalyzed biodegradation of polyurethanes.

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.

Full frame distilled prediction

Teacher imitation

Not 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.

metaresearch head score (Codex)0.000
metaresearch head score (Gemma)0.000
Version: codex-gemma-dda1882f352aValidation status: machine_predicted_unvalidated
Candidate categoriesnone
Consensus categoriesnone
DomainCandidate signal: none · Consensus signal: none
Study designCandidate signal: Bench or experimental · Consensus signal: Bench or experimental
GenreCandidate signal: Empirical · Consensus signal: Empirical
Teacher disagreement score0.001
Threshold uncertainty score0.416

Codex and Gemma teacher scores by category

CategoryCodexGemma
Metaresearch0.0000.000
Meta-epidemiology (narrow)0.0000.000
Meta-epidemiology (broad)0.0000.000
Bibliometrics0.0000.000
Science and technology studies0.0000.001
Scholarly communication0.0000.000
Open science0.0000.000
Research integrity0.0000.000
Insufficient payload (model declined to judge)0.0000.000

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.

Opus teacher head0.014
GPT teacher head0.231
Teacher spread0.217 · how far apart the two teachers sit on this one work
Validation statusscore_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from it