Optical slice

Salt glands of plants from Atriplex genus contain inclusions in the form of crystals of siliceous or sulphate salts of calcium and magnesium (Fahn, 1979). Usually the crystal particles also include phenols (see Chapter 7). The crystals are seen as dark dense spots within the structures on OCM images of the optical slices from the gland (Fig. 4). Profiles of signal intensity along... 

Principle Well-seen image of a cellular structure and its optical slices show the changes induced by many experimental factors, including allelochemical testing. 

Fig. 3 Optical slices (through 1 pm) of vegetative microspore of Equisetum arvense. Excitement with laser beams 488 (emission > 520 nm, green pseudocolor), 543 and 633 nm (fluorescence is observed at 650-750 nm, red pseudocolor).

Fig. 5 The LCSM images of the pollen of Hippeastrum hybridum. Left - common image of dry pollen (excitation by laser beam 458 nm, emission > 520 nm and laser beam 633 nm, emission >670 nm), Right - the stack of optical slices cut through 2 mm of wet pollen (excitation by laser beam 458 nm, emission at 518 nm). Bar = 50 pm...

One of the features of confocal microscopy is that it can produce optical slices of defined thickness through thick specimens. Using a lens of high numerical aperture, thickness of the confocal sections can reach a theoretical limit of about 0.5 pm. Therefore, by moving the specimen up and down, a three-dimensional (3-D) image can be recorded. 

FIGURE 13.7 Reconstituted CLSM optical slices of the stratum corneum of the skin following skin delivery of FITC-Bac in vivo in SD rats. Comparison of skin permeation routes from systems containing 0.1% FITC-Bac following an 8 h skin exposure ethosomes vs. liposomes and hydroethanolic solution. (Reproduced from Godin, B. Touitou, E., J. Control. Release, 94, 365, 2004. With permission from Elsevier.)... 

Due to the efficient rejection of out-of focus photons, confocal microscopy can gain a factor of 1.3 in resolution compared to a conventional optical microscope. More important, however, is another benefit of the con-focal geometry it is possible to perform optical slicing of thick, transparent objects by simply shifting the focal plane to different positions along the optical axis and recording an image at each of these positions. For an excellent review on confocal microscopy see [39,40],... 

Detailed three-dimensional measurements of ICEO flows are now possible in microfluidic devices. Using particle-image velocimetry applied to thin optical slices, the ICEO flow field around a platinum cylinder has recently been reconstructed experimentally (Fig. 5b) and found to agree well with the theory, up to a scaling factor which could perhaps be attributable to compact-layer effects [6]. There has also been extensive experimental work on AC electro-osmotic flows in microfluidic devices, as discussed in a separate article. 

M. Ichiyanagi, Y. Sato, K. Hishida, Optically sliced measurement of velocity and ph distribution in microchannel. Exp. Fluids, 2007, 43 (2-3), 425-435. 

Park JS, Cjoi CK, Kihm KD (2004) Optically sliced micro-PIV using confocal laser scanning microscopy (CLSM), Exp. in Fluids 37 105-119... 

Fig. 20a-c Two-dimensional (2D) optical slices of the DPB/PB mixture undergoing SD at 40 °C for 2,846 min. Binarized images at three different depths from the glass surface, z, are presented a z=0 (at glass surface), b z 4 /im, c z=25 //m. White and black regions of the 2D images correspond, respectively, to PB-rich and DPB-rich phases. Bar corresponds to 100 i m... 

Figure 20 shows 2D optical slices of the DPB/PB mixture imdergoing SD at 40 °C for 2,846 min at three different depths, z, from the glass surface. The volume fraction of the PB-rich phase, 0pb, was found to be nearly 0.8 at the glass surface (see Fig. 20a), while 0pb at z 4 //m was only 0.2 (see Fig. 20b). 2D optical slices of the phase-separated structure at this depth looked much like an island-in-sea structure (PB-rich domains are islands), being different from that of the conventional bicontinuous structure deeper inside the specimen (z=25 //m) (see Fig. 20c). Such drastic variation of pb is demonstrated in Fig. 21, in which 0pb is plotted against z for the DPB/PB mixture (t=2,846 min).

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