Effect of artificial gravity on calcaneal bone marrow adipose tissue and mineral content in female and male participants in 60 days of bed rest
Bibliographic record
Abstract
Abstract Modulation of bone marrow adipose tissue (BMAT) with prolonged inactivity was reported in haemopoietic but not in non‐haemopoietic bones. This prospective randomized controlled trial submitted 16 men and 8 women to 60 days of 6° head‐down‐tilt bed rest. They were assigned to control, continuous or intermittent artificial gravity (AG) interventions. The AG consisted of daily centrifugation at 2 g for 30 min. The serial foot pain questionnaire, MRI and dual‐energy X‐ray absorptiometry of the calcaneus were performed at baseline, during bed rest and at reambulation. At baseline, all groups had comparable calcaneal BMAT ( P = 0.581) and bone mineral density (BMD) ( P = 0.574). After bed rest, 83% of participants reported foot pain. Calcaneal BMAT was not significantly modulated after 60 days of bed rest (control, +0.2% ± 0.8%; continuous AG, +0.5% ± 1.1%; and intermittent AG, +0.1% ± 1.5%; P = 0.368). Calcaneal BMD was reduced at reambulation days 3 and 11 after 60 days of bed rest (−0.05 ± 0.06 and −0.06 ± 0.12 g/cm 2 , respectively; P = 0.008 and P = 0.020). The AG interventions did not significantly alter calcaneal BMAT or BMD. Sex‐based analyses demonstrated calcaneal BMD loss in men but not in women. Calcaneal BMAT and BMD were inversely correlated in women and in men (Spearman's ρ, −0.40 and −0.28, respectively; both P = 0.020). Sixty days of bed rest caused foot pain and calcaneal demineralization not rescued by AG interventions. Although inversely correlated with BMD, calcaneal BMAT was not statistically increased by 60 days of head‐down‐tilt bed rest, possibly owing to a ceiling effect, and no bone marrow reconversion was measured at reambulation. These results have clinical relevance when returning to activities after prolonged bed rest or returning from space.
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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 | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| 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".