Mephedrone (Methylmethcathinone) in Toxicology Casework: A Northern Ireland Perspective
Bibliographic record
Abstract
Mephedrone (4-methylmethcathinone) is the beta-keto analogue of 4-methylmethylamphetamine. Before its control in April 2010, it became popular as a legal high in the United Kingdom, displacing methylenedioxymethylamphetamine as the stimulant drug of choice. The drug has stimulant and psychoactive properties, and therefore has forensic significance in criminal and morbid toxicology. The purpose of this study was to survey casework involving the drug (impaired driving and sudden death). The cases were received in the laboratory for analysis between late 2009 and the end of 2010. Analysis of blood samples for mephedrone was conducted by liquid chromatography-mass spectrometry (LC-MS). Routine screening for alcohol and a range of other pharmaceuticals and drugs of abuse was conducted using a combination of enzyme-linked immunoassay, gas chromatography (GC) headspace, GC-MS and high-performance liquid chromatography with diode array detection. Mephedrone was detected in a total of 12 fatal cases. Most of these cases involved death by mechanical means; in two cases, death was attributed directly to mephedrone intoxication (blood concentrations of 2.1 and 1.94 mg/L). Mephedrone was detected in a total of 32 impaired driving cases. Blood concentrations ranged up to 0.74 mg/L (mean 0.21, median 0.10). The casework evidence in this study indicated that recreational use of the drug can produce to blood levels as high as 0.74 mg/L, although the most common value encountered is likely to lie between 0.2 and 0.3 mg/L.
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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 | 0.002 | 0.007 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.005 | 0.003 |
| Science and technology studies | 0.002 | 0.004 |
| Scholarly communication | 0.004 | 0.003 |
| Open science | 0.003 | 0.004 |
| Research integrity | 0.004 | 0.002 |
| Insufficient payload (model declined to judge) | 0.009 | 0.002 |
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".