Biodegradation of bovine spongiform encephalopathy prions in compost
Bibliographic record
Abstract
Abstract To reduce the transmission risk of bovine spongiform encephalopathy prions (PrPBSE), specified risk materials (SRM) that can harbour PrPBSE are prevented from entering the feed and food chains. As composting is one approach to disposing of SRM, we investigated the inactivation of PrPBSE in lab-scale composters over 28 days and in bin composters over 106–120 days. Lab-scale composting was conducted using 45 kg of feedlot manure with and without chicken feathers. Based on protein misfolding cyclic amplification (PMCA), after 28 days of composting, PrPBSE seeding activity was reduced by 3–4 log10 with feathers and 3 log10 without. Bin composters were constructed using ~ 2200 kg feedlot manure and repeated in 2017 and 2018. PMCA results showed that seeding activity of PrPBSE was reduced by 1–2 log10 in the centre, but only by 1 log10 in the bottom of bin composters. Subsequent assessment by transgenic (Tgbov XV) mouse bioassay confirmed a similar reduction in PrPBSE infectivity. Enrichment for proteolytic microorganisms through the addition of feathers to compost could enhance PrPBSE degradation. In addition to temperature, other factors including varying concentrations of PrPBSE and the nature of proteolytic microbial populations may be responsible for differential degradation of PrPBSE during composting.
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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".