Embedding in epoxy

Figure 2 shows STEM images of a 8%wt Pd/2%wt Pt catalyst which is supported on charcoal. The sample was prepared for microscopy by embedding in epoxy resin and sectioning with a diamond knife in an ultramicrotome, and was examined in a Vacuum Generator s Ltd HB5 STEM, with a 5A probe. The sample thickness is about 500A. 

Tissue processing tissue specimen (0.5 1.0 mm3) are fixed in 4% buffered formalin for 30 60 min, post-fixed in 1% osmium tetroxide in cacodylate or phosphate buffer, pH 7.2 7.4, stained en bloc for 30 min with 2% aqueous uranyl acetate, then dehydrated in ethanol and embedded in epoxy or acrylic resin. 

Ren Y, Fu YQ, Liao K, Li F, Cheng HM (2004). Fatigue failure mechanisms of single-walled carbon nanotube ropes embedded in epoxy. Appl. Phys. Lett. 84 2811-2813. 

Many Quantro II membranes varying incrementally in composition have been under test for 18 months at Albany International Research Co. Tests are performed on experimental samples of fiber. Approximately 16 inches of multifilament yarn are typically subjected to various feeds and conditions. Such a yarn sample is embedded in epoxy which is sealed into a pressure system. Several test facilities are in operation to provide various feeds and conditions. 

Fig. 13.3.7 Typical SEM photographs of a bare polyethylene surface and silica arrangements, embedded in epoxy resin after fracture (a and d) detached silica (0.3 p,m) arrangement after fracture (b) silica (0.3 p,m) arrangement before fracture (c) bare polyethylene surface after fracture (10 p,m).

Single particles are analyzed directly by being fixed on such tape or embedded in epoxy, and mass spectrometric measurements are carried out on cut and polished cross sections. 

In TEM, thin sections of samples are embedded in epoxy resins or, alternatively, platinum-carbon replicas of the samples are produced in order to the avoid release of vapor or gases. 

Fig. 5 TEM micrograph of a craze in bulk HDPE deformed in tension at room temperature (embedded in epoxy and stained in Ru04)...

Fig. 8a, b The crack-tip deformation zone in a first generation HDPE tested with an initial K of 0.3 MPa m1/2 in air. a Low magnification TEM image of the deformation zone tip (the dark areas of over-stained epoxy correspond to cavities), b Detail of the internal structure of the region marked (i) in a (embedded in epoxy and stained in Ru04, tensile axis as indicated by the arrows) [73]... 

After the last experiments, the rats are euthanized by injection of an overdose of pentobarbital and then perfused intracardially with a phosphate-buffered 2.0% paraformadehyde - 2.5% glutaraldehyde fixative. Methyl green solution was injected to confirm the location of the catheter after the perfusion. The spinal cord and nerve roots were dissected out and immersed in the same fixative for 4 h. Two specimens (10 mm rostral and caudal to the conus medullaris from each rat were postfixed with cacodylate-buffered 1 % osmium tetroxide dehydrated in a series of graded alcohol solutions, and embedded in epoxy resin. From the embedded tissue, 1-pm transverse sections were obtained and stained with toluidine blue dyes. Sections obtained from 10 mm rostral to the conus (caudal spinal cord) were used for qualitative evaluation. Quantitative analysis of nerve injury was performed using the sections obtained form 10 mm caudal to the conus. Each fascicle present in the cross section was assigned to an injury score 0 to 3. The injury score for each cross section was then calculated as the average score of all fascicles present in the cross section. 

Polished embedded in epoxy samples were analyzed by Camebax SX-50 electron probe microanalyzer. Element mapping were recorded by means of WDX-spectrometer with the Ep = 15 kV from the area 512 x 512 /[Pg.219]

Zeolite single crystals may serve as zeolite membrane models. We mention the early elegant work of Hayhurst and Paravar [10] on an oriented large silicalite-1 crystal embedded in epoxy resin. 

Several plagioclasc grains from annealed samples as well as shock-loaded run products were embedded in epoxy resin and polished. Observation was performed with an optical microscope using reflected and transmitted light Major and minor element compositions were determined by an electron probe microanalyzer. Shock textures were also examined in detail with a scanning electron microscope using back-scattered electron images. 

Scanning force microscopy (SFM) has been widely used for visualization of biomedical objects because of combination of extreme resolution, simplicity of sample preparation and ability to operate under physiological conditions. Nowadays SFM is increasingly applied to investigate the ultrastructure of biomedical samples embedded in epoxy resin [1]. In the present work, we are focusing on application of SFM, confocal laser scanning microscopy and ultramicrotomy to the K562 leukemic cells study. 

The aim of this study is to apply SFM combined with confocal laser scanning microscopy to investigate K562 cells surface morphology in details. Also an attempt was made to visualize with SFM the internal ultrastructure of embedded in epoxy resin of K562 leukemic cells. 

Figure 3. SFM image of the internal ultrastructure of embedded in epoxy resin of K562 cell.

Fig. 3 shows SFM image of one of the sections (thickness of - 100 nm) of K562 cell embedded in epoxy resin. It should be noticed that topographical contrast and the identification of the K562 internal ultrastructure critically depend on the procedure of cell preparation before embedding (chemical fixation or high-pressure freezing and freeze-substitution). 

Figure 2 illustrates how a typical analysis was conducted. An SEM micrograph of an alumina particle, a cross section embedded in epoxy in this case, was generated first. Then the electron beam was parked at different spots in this cross-section and an EDS elemental analysis was performed. The sampling volume in this mode of analysis was an order of magnitude smaller than the dimension of alumina particles. 

TEM (Transmission Electron Microscopy) analysis. This analysis was done on a Philips 420T microscope (120kV, maximum resolution 5A) equipped with an EDAX PV9900 EDS. The catalysts were ground to a powder, embedded in epoxy resin and then microtomed with a diamond l fe to obtain sections about 300A thick. Images were taken at 100 kV. Diameters of about 100 isometric-shaped Pt crystallites were measured for each sample. 

Fig. 4. Electron micrographs of L-Asp-LI and L-GIu-LI in hippocampus CAl from a hypoglycemic rat subjected to perfusion fixation. The tissue was treated with uranyl acetate before embedding in epoxy resin. The figure shows accumulation of immunoreactivities over synaptic vesicle clusters (sv) versus over cytoplasmic matrix (cm) in terminals making asymmetrical synapses on spines (s). Broken lines mark the houndary between the vesicle-rich and vesicle-poor parts of the terminals. Scale bar = 0.2 pm. (Modified from Gundersen et al., 1998.)...

The crystals were embedded in epoxy, cut longitudinal and polished using diamond spray down to a grain size of 3 pm. Fig. 2b shows a SEM image of a crystal with a gradient in the chromium doping. In this case a crystal with a sharp transition was investigated. 

There are two different ways to perform electron microscopic immunocytochemistry pre-embedding and postembedding (Stirling, 1990). Pre-embedding electron microscopic immunocytochemistry applies the antibodies and label to samples just after fixation but before embedding in epoxy resin and sectioning. Postembedding electron microscopic immunocytochemistry applies antibodies and label to thin sections made after the samples have been embedded in epoxy resin and sectioned. 

Postembedding electron microscopic immunocytochemistry - a method that uses antibodies applied to sections after embedding in epoxy resin and sectioning with an ultramicrotome. 

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