Replacement of hydroxylapatite by whewellite: implications for kidney-stone formation
Bibliographic record
Abstract
Abstract Kidney stones consisting predominantly of whewellite (calcium oxalate monohydrate, COM) are often found attached to hydroxylapatite (HA) plaques that form in the soft tissue of kidneys, cause lesions and become exposed to urine. Although the processes of stone formation are not entirely known, it is an established view that so-called Randall’s plaques serve as substrates for COM crystal nucleation and growth from correspondingly supersaturated urine. However, the results presented here suggest an additional mineral replacement process is involved. In an experimental approach, HA was reacted in 0.25 mM, 0.5 mM and 1.0 mM oxalate solutions with pH ranging from 4.5 to 7.5, simulating normal to harsh conditions encountered in urine. Extremely acidic solutions induce dissolution of HA crystals coupled with re-precipitation of the released Ca2+ ions as COM on the HA surface. When, instead, bone was used as a substrate, being more similar to the pathological plaque (aggregated HA nanocrystals within an organic matrix), the HA-COM mineral-replacement reaction is induced even under much milder fluid conditions, commonly found in urine. Hence, a process of COM partly replacing and encrusting Randall’s plaque may take place in the urinary tract of idiopathic stone formers, representing a potential starting event for nephrolithiasis.
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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 | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 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".