Verification of physicochemical structures of dialysis membrane using reversal dialysis technique
Bibliographic record
Abstract
Abstract Objective: Solute removal performance of the dialyzer is closely related to physicochemical structures of the membrane. The objective of this study is to devise a new in vitro evaluation technique to directly correlate the physicochemical structures of the membrane to the dialysis performance. Materials and Methods: Commercial 11 dialyzers with cellulose triacetate (CTA), ethylene vinylalcohol co‐polymer (EVAL), asymmetry CTA (termed ATA), 4 polysulfone (PSf), polyether sulfone (PES), and 3 polyester polymer alloy (PEPA) membranes were employed for investigation. Normal dialysis experiments were performed with aqueous creatinine (MW 113), bromophenol blue (MW 670), vitamin B12 (MW 1355), chymotrypsin (MW 25,000) test solutions. Reversal dialysis experiments were devised introducing the test solution outside the hollow fiber (HF) and the dialysate inside the HF, respectively. Clearances were measured under QB = 200 mL/min and QD = 500 mL/min at 310 K. The ratio of clearance in the reversal dialysis to that in the normal dialysis termed the yielding factor of asymmetry, fYA, was defined for evaluation. Results and Discussion: According to the classic mass transfer theory, clearance in the normal dialysis and that in the reversal dialysis are expected to be identical; however, the average fYA was 0.96 for creatinine and was always slightly lower than unity in 10 dialyzers out of 11. This may be caused by un‐uniform distribution of the test solution outside the HF, which was more likely to occur than when it flowed inside the HF. Unlike creatinine, the average fYA for vitamin B12 was 1.0 and that for chymotrypsin was 1.06 to 1.45 in membranes with heterogeneous structures (ATA, PSf, PEPA, and PES), but was almost unity (1.02) in homogeneous membrane (CTA). This must be based on the fact that the membrane permeability in the reversal dialysis is much larger than that in the normal dialysis due to the physicochemical structures of the heterogeneous membrane that has a wedge‐like pore size distribution in the radial direction. Conclusions: A wedge‐like pore size distribution in the radial direction in heterogeneous membrane was semiquantitatively evaluated by introducing a reversal dialysis technique with a new index.
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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) | 0.000 | 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 | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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".