Chemical and Physical Characterization of McIntyre Powder using Inductively Coupled Plasma Mass Spectroscopy and Electron Microscopy
Bibliographic record
Abstract
Aim: The objective of this study was to determine the chemical and physical characteristics of McIntyre powder, which was stated to be a mixture of aluminum oxide and elemental aluminum. The aim was to (i) confirm this with current techniques and to see if there were any toxic metals present, which could contribute to health effects including neurological disorders, Parkinsons and (ii) obtain a precise particle size distribution. McIntyre Powder was inhaled by at least 27,500 gold and uranium miners of Ontario as a prophylaxis to prevent silicosis during 1944-1979. Materials and Methods: The chemical characterization involved analysis by inductively coupled plasma mass spectroscopy (ICP-MS) and by scanning electron microscopy. The physical characterization was carried out using transmission electron microscopy. Results: The chemical analysis results confirm that the McIntyre Powder contains mainly aluminum and only trace amounts of other metals. The physical characterization shows that it is about 12% ultra fine (also referred to as nano particles) and 88% fine particles. Approximate aerodynamic diameters of the particles are mean 321.5 nm (0.32 im), median 273.8 nm (0.27 im) with a range of 9.5 nm (0.01 im) to 1314 nm (1.31 im). Conclusion: There are no metallic impurities in McIntyre Powder in quantities that could make a significant contribution to health effects. There is a 12% ultrafine particle content which could be important because of the apparent ability to translocate to the brain.
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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 | 0.001 | 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".