Variation of Chemical Composition of the Lipophilic Extracts from Yellow Birch (<i>Betula alleghaniensis</i>) Foliage
Bibliographic record
Abstract
The occurrence of biologically active compounds identified for the first time in the lipophilic extracts of yellow birch (Betula alleghaniensis Britt.) foliage led to the quantification of the seasonal variation of their concentrations. Yellow birch foliage was collected from late June until late September 2003 in two different regions of Quebec. The extraction yields using hexane as a solvent were determined, and the extracts were analyzed by GC-MS to identify their molecular composition. In terms of both extraction yields and the concentration of the targeted molecules present in the extracts, mid-September has been determined as the best time to collect foliage samples. A total of 14 constituents were identified in these extracts. This is the first report of the presence of all of these constituents in yellow birch foliage and of some of them in the genus Betula. The most important compounds identified in yellow birch foliage extracts are triterpene squalene and aliphatic hydrocarbon tetracosan, aliphatic alcohol phytol, fatty acids hexadecanoic and octadecanoic, pentacyclic triterpenes alpha- and beta-amyrin, and phytosterol stigmast-5-en-3-ol.
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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".