Analysis of Western Redcedar (Thuja plicata Donn) Heartwood Components by HPLC as a Possible Screening Tool for Trees with Enhanced Natural Durability
Bibliographic record
Abstract
A method is described for the quantitative analysis of seven known compounds, specifically plicatic acid, thujaplicatin methyl ether, beta-thujaplicin, gamma-thujaplicin, beta-thujaplicinol, thujic acid, and methyl thujate, in the ethanol extract of second growth western redcedar heartwood (Thuja plicata Donn) by high-performance liquid chromatography using diode array detection. The para bromo phenacyl ester of crotonic acid is synthesized for use as the internal standard for the method. Separation of compounds covering a wide range of polarities is achieved using an Inertsil ODS 3 3-micro column. Twenty seven second growth trees ranging in age from 40 to 125 years, originating from the coastal and interior regions of British Columbia, are selected for analysis and profiled using the described method. Samples consisting of five growth rings each are analyzed from the heartwood-sapwood boundary to the pith for each tree. Substantial variation in most heartwood compounds are detected within and between trees within a region. Significant variation in beta-thujaplicin, the ratio between gamma- and beta-thujaplicin, and methyl thujate is detected between coastal and interior populations.
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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".