Microscopy microscope slide

Particles become positively charged by a corona discharge and travel out of the charging chamber and collect on a substrate such as a microscope slide. Thus, the method is useful for particles which are to be examined by optical or electron microscopy. 

Observations are made in metaphase cells arrested with a spindle inhibitor such as colchicine or colcemid to accumulate cells in a metaphase-like stage of mitosis (c-metaphase) before hypotonic treatment to enlarge cells and fixation with alcohol-acetic acid solution. Cells are then dispersed on to microscope slides and stained and slides are randomized, coded and analyzed for chromosome aberrations with high-power light microscopy. Details of the procedure are given in Dean and Danford (1984) and Preston et al. (1981, 1987). The UKEMS guidelines (Scott et al., 1990) recommend that all tests be repeated regardless of the outcome of the first test and... 

Figure 9.29 Membrane formation by meteoritic amphiphilic compounds (courtesy of David Deamer). A sample of the Murchison meteorite was extracted with the chloroform-methanol-water solvent described by Deamer and Pashley, 1989. Amphiphilic compounds were isolated chromatographically on thin-layer chromatography plates (fraction 1), and a small aliquot ( 1 p,g) was dried on a glass microscope slide. Alkaline carbonate buffer (15 p,l, 10 mM, pH 9.0) was added to the dried sample, followed by a cover slip, and the interaction of the aqueous phase with the sample was followed by phase-contrast and fluorescence microscopy, (a) The sample-buffer interface was 1 min. The aqueous phase penetrated the viscous sample, causing spherical structures to appear at the interface and fall away into the medium, (b) After 30 min, large numbers of vesicular structures are produced as the buffer further penetrates the sample, (c) The vesicular nature of the structures in (b) is clearly demonstrated by fluorescence microscopy. Original magnification in (a) is x 160 in (b) and (c) x 400.

For inorganic substances, chemical reactions may be carried out on a small scale on microscope slides, the crystallization of reaction products being watched. Tests for particular ions or atom groups have been devised, the criterion of identity being, not solubility or colour, as in macroscopic qualitative chemical analysis, but crystallographic properties. For information on such methods, see Handbook of Chemical Microscopy, by Chamot and Mason (1958). 

Size Measurement. After the fractions were filtered, the millipore filters were sectioned to provide separate portions for chemical analysis and for size distribution measurements. One-eighth or one-fourth was set aside in reserve. The section designated for optical microscopy was transferred to a microscope slide and placed in a covered petri dish with a few drops of acetone. The acetone vapor is absorbed by the millipore and renders the filter transparent. 

The size fractions measured by electron microscopy were redispersed before filtration in a sonic shaker. About 100-200 was transferred to a microscope slide. After drying, a small amount of collodion (4% in amyl acetate) was added, and the solvent was allowed to evaporate. The collodion film was scribed into 3 mm. squares, floated off on water, and gathered on electron microscope grids. 

Analyze by FACS or by pipeting the cells onto a microscope slide for confocal laser microscopy. 

Digital microscopy is used to extract quantitative information from microscopic slides. A digital microscopic imaging system consists of the following six components (Huang, 1981b) ... 

Sample preparation must be done carefully because biases in sample preparation will lead to inaccurate results. The statistical diameters that are popular for characterizing particles in microscopy are based on a random orientation thus, biases in orientation due to improper sample preparation will affect the values. Any factors that cause the particles to preferentially orient on the microscope slide will affect the results. For example, spreading the particles out with a spatula may causes a preferential orientation. Another example is particles dispersed in a liquid when the liquid is sprayed or poured onto the microscope slide the particles could orient themselves with the flow lines of the liquid and this could lead to their non random orientation. 

It should also be mentioned that the majority of microbial airborne particles are dead or noncultivable , which means that they do not grow under the laboratory conditions chosen. This is, for example, true for microorganisms hke Stachybotrys chartarum. To fully survey the indoor microbial situation and to avoid overlooking fungal species which may be indicators of damage, additional samples have to be taken using methods hke direct microscopy which are not dependent on hving, cultivable cultures. Here, for example, microscopic slides with an adhesive surface are inserted in special impactor samplers. The airborne particles collected are stained in the laboratory. EspeciaUy spores with a characteristic shape hke those of S. chartarum are easily detected under the microscope. 

Techniques for phase identification are similar to those employed for thermotropic liquid crystals, although there are differences. Thus, optical microscopy is the most common technique used, but rather than prepare multiple samples at a range of concentrations it is more common to perform Lawrence Penetration Experiments [189]. In this experiment, some solid surfactant (maybe up to 50 mg) is placed on a microscope slide and a cover slip placed on the top. Water (or which ever solvent is to be used) is placed at the end of the cover slip and proceeds from one end to the other by capillary action, thus, setting up a concentration gradient across the sample. Now, at any given temperature, it is possible to have a snapshot of the whole phase diagram, and clear phase boundaries can often be seen. This experiment can be very... 

In the U.S. in 1957, McCrone presented a review of fusion methods, techniques, equipment, and applications (12). His definition of fusion methods included the methods and procedures useful in research and analysis, which involved heating a compound or mixture of compounds on a microscope slide (12). His text comprises five parts. Chapter I is an introduction discussing the scope and limitations of fusion microscopy, and Chapter II discusses the commercially available equipment at the time. Chapter III details the general techniques for hot stages, cold stages, and hot bars, characterization and identification of organic compounds, purity estimations,... 

Microscopy is not relevant to aerodynamic particle size, since the particles are stationary on the microscope slide. The technique is, however, asked for by some regulatory agencies. It is of value during development for examining deaggregation or Ostwald ripening. 

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