DNA Interduplex Crosslinks Induced by Al<sub>Kα</sub>X Rays under Vacuum
Bibliographic record
Abstract
Dry pGEM-3Zf(-) plasmid DNA was exposed to Al(kalpha) X rays (1.5 keV) for various times in an ultra-high vacuum chamber with mean absorbed dose rates ranging from 1.8 to 41.7 Gy s(-1). The different forms of plasmid DNA were separated by neutral agarose gel electrophoresis and quantified by staining and laser scanning. In addition to the bands for supercoiled, nicked circular, linear and concatameric forms of plasmid DNA, two additional bands were observed in X-irradiated samples; these migrated at rates similar to those for 8-kb and >10-kb linear double-stranded DNA. Digestion of irradiated DNA with the restriction enzymes EcoR1 and PvuI suggested that the two slowly migrating bands were interduplex crosslinked DNA. Alkaline agarose gel electrophoresis of irradiated DNA digested with EcoR1 confirmed that the interduplex crosslink was covalent. Exposure-response curves were determined for the formation of nicked circular, linear and interduplex crosslinked DNA as well as for the loss of supercoiled and concatameric DNA. Formation and loss of these species were independent of absorbed dose rate over a 20-fold range. The G values for DNA single-strand breaks, double-strand breaks and crosslinks were determined to be 62 +/- 6, 5.6 +/- 0.6 and 16 +/- 4 nmol J(-1), respectively. The formation of DNA interduplex crosslinks appears to be due to single event. The mechanism responsible for the formation of DNA interduplex crosslinks is discussed with emphasis on its implications in vivo.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot 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.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 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) | 0.000 | 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 teacher head, 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".