Structure of Phenylalanine Adsorbed on Polystyrene from Nonlinear Vibrational Spectroscopy Measurements and Electronic Structure Calculations
Bibliographic record
Abstract
We have used nonlinear vibrational spectroscopy to determine the structure of l -phenylalanine adsorbed at the solution−polystyrene interface. Quantitative analysis of nonlinear susceptibility tensor elements was enabled by collecting spectra under various calibrated polarization schemes. We have proposed a technique for fitting the spectra that is well-suited to the challenging line shape resulting from coherent interferences between vibrational modes. Molecular-level vibrational hyperpolarizabilities have then been determined by electronic structure calculations with use of an effective solvent model. These hyperpolarizability values are used to predict spectral amplitudes for comparison with experimental results in order to determine the orientation distribution of the phenylalanine CH 2 plane. We have found that the orientation of phenylalanine is relatively constrained at the polymer surface. Our data and analysis suggest amino acid aromatic rings may be inserted into polystyrene surface aromatic rings to achieve this quasi-immobilization.
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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".