Low-e glass slide

Twenty human coronary tissue sections were obtained postmortem and mounted in paraffin onto low-e glass slides for IR microspectroscopy. A visible light image of a stained section of human coronary atherosclerotic plaque appears in Figure 34.7. This section was adjacent to the section used for IR microspectrometric imaging (see Figure 34.8). 

Individual cells may also be deposited onto a Cap2 window support, but perhaps the more practical and most appropriate (in terms of its match to cytological practices) method nowadays is to use a low-e glass slide and record a transflection spectrum, see next section. 

Vibrational microspectrometry will undoubtedly be applied to medical diagnosis in the near future. One particularly important application of microspectrometry is for the characterization of tissue samples. Tissue samples can be mounted on a water-insoluble infrared-transparent window such as ZnSe, but these windows are expensive and not conducive to visual examination (e.g., after staining of the tissue). A convenient alternative to transmission spectrometry is the measurement of the transflectance spectrum (see Section 13.5) of tissue samples mounted on low-emissivity glass slides [4]. These slides are transparent to visible light but highly reflective to mid-infrared radiation. 

Thin-film preparation is important, as in the case of the polythiophenes. The thin films can be obtained on suitable substrates such as glass slides either by casting from solution or by vacuum evaporation. In particular, the relatively low molecular weight of the materials enables a moderate rate of evaporation, ensuring the preparation of exceedingly uniform thin film [78]. Vacuum evaporation is usually carried out e.g. at a pressure of 10 Torr and at an appropriately elevated temperature of 180°C [79]. The thickness of the deposit can be controlled by adjusting the sample concentration in the solution or by changing the sample amount fed into a cmcible. 

The samples are usually prepared as thin films deposited on a suitable support (e.g., a glass slide), plates, or powders. However, by utilizing special accessories (e.g., optical fiber probes) and instrumental setups, in principle one can perform photoluminescence experiments on any object. As a consequence of the front-face geometry and the low transparency of the sample, it is often the case that luminescence measurements on solids involve only the outer part of the sample, for a depth on the order of a few micrometers or less. Therefore, particularly in the case of powdered samples, it is important to obtain a homogeneous dispersion of the granules and deposit it as a thin layer on a transparent support, such as glass or quartz, potentially utilizing an inert medium like mineral oil. 

For low-resolution work, we have used a low-NA, dry objective mounted on an upright microscope and have injected embryos mounted on a coverslip resting directly on a glass slide. This strategy is useful if injected embryos are subsequently observed on another microscope (e.g., an inverted, scanning confocal microscope). 

The shape of the maser curve not only depends on the rubber compound, but also on the surface on which it slides. On dry, clean polished glass the friction master curve for gum rubbers rises from very small values at low log ajv to a maximum which may reach friction coefficients of more than 3 and falls at high log ajv to values which are normally associated with hard materials, i.e., 0.3 shown for an ABR gum compound in Figure 26.2. If the position of the maximum on the log a-fV axis for different gum rubbers is compared with that of their maximum log E frequency curves, a constant length A = 6 X 10 m results which is of molecular dimension, indicating that this is an adhesion process [10]. 

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