Quantifying the backscattering of second harmonic generation in tissues with confocal multiphoton microscopy
Bibliographic record
Abstract
The backward second harmonic generation (SHG) in mouse tissues is studied with a confocal multiphoton microscopy system. The total backward collected SHG (B-SHG) consists of the backward generated SHG and the backward-scattered forward-generated SHG (BS-SHG), which can be modeled by a Gaussian and a uniform distribution, respectively, at the confocal pinhole plane. By varying the pinhole size with a series of collection fibers, the proportion of the BS-SHG to the B-SHG and the proportion of BS-SHG to the forward generated SHG can be obtained. The approach is first validated by Monte Carlo simulation. It is then applied to two types of mouse tissues: mouse tail tendon and Achilles tendon. It is found that the BS-SHG contributes less to the B-SHG for the tail tendon than Achilles tendon with thicknesses of ~300 μm. With the thickness of the Achilles tendon tissue increased to 1000 μm but the focal plane kept at the same depth, as high as ~10% of the total forward SHG is backscattered and collected. The results indicate that BS-SHG may not be the major source of B-SHG in the tail tendon, but it may be the major source in the Achilles tendon. These methods and results provide a noninvasive method and supporting information for investigating the generation mechanism of SHG and help with optimizing backward SHG microscopy and spectroscopy measurements.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| 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 | 0.000 | 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 teacher head, 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".