Bibliographic record
Abstract
Long-term human spaceflight presents unprecedented challenges to the human body, such as microgravity-induced bone loss. Without intervention, astronauts lose between 1 – 2% bone mineral density per month in weight bearing bones and the cellular mechanisms involved in this process are still poorly understood. To date, the most abundant cell of bone, the osteocyte, has rarely been subjected to spaceflight. Yet osteocytes are known to be important regulators of bone loss in immobilized and elderly people. The first objective of this thesis was to develop novel 3D culture methods to study osteocytes using the Rotary Cell Culture System (RCCS). This device is commonly used for both suspension culture and simulated microgravity by clinorotation. The second objective was to investigate morphological and gene expression changes in MLO-Y4 cells following suspension culture or clinorotation. We found that the ideal 3D scaffold consisted of 2% type I collagen mixed with 6% synthetic hydroxyapatite (collagen-HA). The scaffold was successfully formed into droplets for suspension culture, whereas it was adhered to the RCCS vessel walls for clinorotation. After 3 days of suspension culture, MLO-Y4 cells embedded in the collagen-HA droplets showed reduced expression of the mechanosensitive genes DMP1, E11, IL-6, and RANKL and the number of cells was elevated compared to the static control. We estimated that the drag force acting on the aggregate of droplets was in the range of 2.1 – 4.4 dynes/cm2, speculated to provide a small but significant stimulatory effect on the cells located on the surface, which may de-sensitize them over the course of 3 days. Following clinorotation for 3 days, MLO-Y4 cells showed reduced expression of DMP1 and E11 genes while the cell number was unchanged compared to the static control. Since clinorotation and spaceflight cause the de-differentiation of other bone cells, we speculated that our MLO-Y4 cells were also de-differentiating during clinorotation, resulting in the lower expression of osteocyte-specific genes.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.001 | 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".