Differential frequency-domain photoacoustic microscope for blood oxygen saturation measurements
Bibliographic record
Abstract
We have developed a low-cost frequency domain differential photoacoustic microscope. The microscope uses a low-cost PA sensor made up of a kHz microphone, low power CW lasers and an optical chopper with 6/5 dual-slot disc. The system used dual-slot chopper disc to modulate two laser beams simultaneously and the corresponding PA signals were measured. This simultaneous modulation enabled a single scan instead of two scans required for two lasers in previous configurations, reducing the scanning time half. The configuration also enabled two PA interrogations at the same location of the sample whereas in the conventional sequential measuring system any backslash of the translation stage would alter the location of the interrogation area during the next measurement. The developed sensor is used to study the oxygen saturation of a single RBC. Two types of RBCs containing predominately oxy and methemoglobin were investigated using three different lasers of wavelengths 473 nm, 533 nm, and 633 nm. The single cell study showed that half of the oxy-RBC and meth-RBC exhibit oxygen saturation of about 90 % and 38.61 % respectively.
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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 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.003 | 0.001 |
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".