Analysis and purification of peptide nucleic acids by denaturing PAGE
Bibliographic record
Abstract
A flexible and convenient protocol for the analysis and purification of peptide nucleic acid (PNA) oligomers and PNA-peptide chimeras by denaturing PAGE is described. Vertical slab gel electrophoresis, 26% in polyacrylamide and 8 M urea at pH 3, was suitable for analysis of oligomers ranging in size from tetramers (4-mers) to tetradodecamers (24-mers). Single-base resolution of oligomers was achieved and separations are generally superior to those given by standard RP-HPLC techniques. The separation of a related series of PNA oligomers showed the distance migrated was linearly dependent on the logarithm of the molecular weight. The migration of oligomers through the gel is dependent on the number of basic functional groups present, such as amino groups, and the A and C content of the oligomer. PNAs are amenable to detection by UV-shadowing technique illuminated at 260 nm or Coomassie blue staining, both with similar, sub-microgram per band detection limits.
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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 | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.000 | 0.002 |
| Insufficient payload (model declined to judge) | 0.003 | 0.005 |
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".