Infrared spectra of carbonate apatites: Evidence for a connection between bone mineral and body fluids
Bibliographic record
Abstract
The complex asymmetric stretch ( ν 3 ) region infrared (IR) spectrum of synthetic sodium- and carbonate-bearing hydroxylapatites (CHAP) has been interpreted using overlapped Gaussian distributions for individual carbonate ion species. There is now good agreement for the distribution of carbonate ions between phosphate (type B) and c -axis channel (type A) positions using three independent methods: X-ray structure site occupancies, out-of-plane bend ( ν 2 ) band areas, and asymmetric stretch ( ν 3 ) band areas; B/A ratios for a well-crystallized CHAP sample being 0.77, 0.78, and 0.75, respectively. The reported dominance of type B carbonate ions in bone mineral and dental enamel is attributed to the anomalous shift of type A band frequencies into the spectral region of type B, resulting from the substitution of Ca 2+ by Na + in the nearest-neighbor cation shell of the channel carbonate ions. The infrared spectra show that the hydrogencarbonate (bicarbonate) ion in apatite crystals is a channel species, as are its room-temperature decomposition products, type A carbonate and labile (type L) carbonate. The research suggests that bone mineral crystals may actively communicate with body fluids through the apatite channel, pointing to a possible role for the apatite channel in mediating acid-base reactions in the body.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| 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) | 0.002 | 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".