We propose a structured illumination microscopy method to combine super resolution and optical sectioning in three‐dimensional (3D) samples that allows the use of two‐dimensional (2D) data ...processing. Indeed, obtaining super‐resolution images of thick samples is a difficult task if low spatial frequencies are present in the in‐focus section of the sample, as these frequencies have to be distinguished from the out‐of‐focus background. A rigorous treatment would require a 3D reconstruction of the whole sample using a 3D point spread function and a 3D stack of structured illumination data. The number of raw images required, 15 per optical section in this case, limits the rate at which high‐resolution images can be obtained. We show that by a succession of two different treatments of structured illumination data we can estimate the contrast of the illumination pattern and remove the out‐of‐focus content from the raw images. After this cleaning step, we can obtain super‐resolution images of optical sections in thick samples using a two‐beam harmonic illumination pattern and a limited number of raw images. This two‐step processing makes it possible to obtain super resolved optical sections in thick samples as fast as if the sample was two‐dimensional.
Lay description
Structured illumination microscopy is a method used to build optical sections that reveal details closest together than the fundamental Abbe resolution limit. Fifteen images are classically required to compute the final super resolved section when the sample is three dimensional, while only seven are sufficient in the two dimensional case. The need for extra images in the three dimensional case is explained by the necessity to disentangle the information contained in optical section from the out of focus content.
In this paper we show that by estimating and subtracting the out of focus content from the images before combining, then only seven images are sufficient to build super resolved optical sections of three dimensional samples. The main difficulty lies in the evaluation of the weight of the out of focus part.
We evaluate the efficiency of our approach using simulated data. We show that it is insensitive to the illumination pattern structure and contrast.
We then present results obtained in a 100 micrometre thick C‐elegans worm. We compare optical sections computed using a limited number of images, with or without background subtraction, that clearly demonstrate the enhancement brought by our approach.
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BFBNIB, DOBA, FZAB, GIS, IJS, IZUM, KILJ, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBMB, SIK, UILJ, UKNU, UL, UM, UPUK
3.
Pathology in Practice Fragola, Jessica A; La Croix, Noelle C; Teixeira, Leandro B C ...
Journal of the American Veterinary Medical Association,
12/2019, Volume:
255, Issue:
12
Journal Article
Objective
To report 14 neoplasia‐free feline eyes enucleated for suspected intraocular neoplasia containing only iridociliary cysts. To analyze clinical findings that may have led veterinarians to ...suspect neoplasia in these globes.
Procedures
The archives at the Comparative Ocular Pathology Laboratory of Wisconsin (COPLOW) were searched to identify neoplasia‐free feline globes enucleated for suspected neoplasia. Clinical data were obtained from medical records, veterinarian surveys, and COPLOW submission forms. All samples were examined grossly and histologically.
Results
All eyes were free of neoplasia and contained one or more iridociliary cysts. Nine of 14 globes were enucleated by or based on the recommendation of a board‐certified veterinary ophthalmologist. In eight of 14 cases, the submitting clinician listed melanoma as the only suspected diagnosis; in six of 14 cases, ‘tumor’ or ‘mass’ was listed. Clinical examination revealed a darkly pigmented intraocular mass in 11 of 14 cases. The mass was clinically perceived to be within the iris in seven of 14 cases. When examined histologically, 11 of 14 eyes contained multiple cysts, 13 of 14 contained multiloculated cysts, eight of 14 had a hyperplastic iris pigmented epithelium or cysts with thick black walls, and five of 14 had cysts prolapsed into the anterior chamber.
Conclusions
Although most iridociliary cysts in cats are easily diagnosed on clinical examination, a subset may be mistaken for neoplasia. In cases of suspected iris melanoma, iridociliary cysts should be considered as a differential diagnosis, especially if a mass appears to emanate from behind the iris, dyscoria is present, or if similar changes are noted in the contralateral eye.
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In this contribution, the ability of simple oximes to bind a well-known nerve agent simulant (dimethylmethylphosphonate, DMMP) via hydrogen bond is reported. UV/Vis measurements indicate the ...formation of 1:1 complexes.
1
H-,
31
P-NMR titrations and T-ROESY experiments confirm that oximes bind the organophosphate via hydrogen bond.
Graphical Abstract
The ability of simple oximes to bind a well-known nerve agent simulant (dimethylmethylphosphonate, DMMP)
via
hydrogen bond is reported. UV/Vis measurements indicate the formation of 1:1 complexes.
1
H-,
31
P-NMR titrations and T-ROESY experiments give evidence that oximes bind the organophosphate
via
hydrogen bond.
We show that apertureless scanning near-field optical microscopes that use sharp vibrating conical tips can be operated in liquid environments. We have investigated the damping of the tip oscillation ...as a function of its shape and as a function of its depth under the liquid surface. The degradation of the quality factor from 150 in air down to 15 in liquid does not impede to perform topographic and optical measurements with a very good sensitivity. As an example of application, we present near-field fluorescence images of dye-doped polystyrene spheres immersed in a liquid.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
We have imaged fluorescent erbium‐doped fluoride glass particles by apertureless scanning near‐field optical microscopy. The optical excitation has been performed at λ = 780 nm whereas fluorescence ...emission has been collected around λ = 550 nm. This process, called upconversion by energy transfer, involves two erbium ions and is not linear. Besides an improvement of the lateral resolution, we have observed on some particles that the fluorescence is not homogeneously distributed, but is rather localized in some zones brighter than others. By making tip approach curves, we have also observed that the amount of fluorescence intensity scattered by the tip is increasing when the tip is approaching the sample surface.
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BFBNIB, DOBA, FZAB, GIS, IJS, IZUM, KILJ, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBMB, SIK, UILJ, UKNU, UL, UM, UPUK
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