Probe studies, electron

Kent, B. E., Fletcher, K. E. Wilson, A. D. (1970). Dental silicate cements XI. Electron probe studies. Journal of Dental Research, 49, 86-92. 

Most kaolinites contain appreciable amounts of MgO (range 0.01—1.0% modal value between 0.2—0.3%). Bundy et al. (1965) found that MgO as well as total iron and soluble iron were directly related to the C.E.C. and suggested that the Mg and Fe were present in montmorillonite which they believe is commonly present, in amounts less than 5%, in kaolinites. This may be true in part, but electron probe studies (Weaver,1968) indicate that some of the MgO is related to the Ti02-Fe203 material and some is present in biotite. 

Boyd F. R. (1969) Electron-probe study of diopside inclusions from kimberlite. Am. J. Sci. 261 A, 50-69. 

Somlyo, A.V., Gonzalez-Serratos, H., Shuman, H., McClellan, G. and Somlyo, A.P. (1981). Calcium release and ionic changes in the sarcoplasmic reticulum of tetanized muscle an electron probe study. J. Cell Biol. 90, 577-594. 

Hooke, R.L., Yang, H. Weiblen, P.W. (1969) Desert varnish an electron probe study. Journal of Geology 77, 275-288. 

Degras and Lecante (81) in an electron-probe study of the CO-molybdenum system has suggested that the ionic desorption product... 

Figure 11. Relative Ft and Pd concentration profiles determined by electron probe studies of polished cross sections...

Electron probe studies have shown that the Jost mechanism is most likely in these cases. Other reactions of the general type discussed here which have been experimentally studied are the displacement reactions ... 

If the usage of AI2O3 is in order to improve the thermo-stability, and their contents are >1% (molar fractions), then in practice they may be solved incompletely, where a part would still exist as a form of separate phases. There is an evidence of electron probe studies for their existence. Thereafter, the maximum content is below 4%, with appropriate value to be about 2% (see Fig. 3.46). To further increase thermal stability, it may be possible to introduce such oxides as MgO, Zr02 and Si02. 

The elemental composition of the fish otoliths is a potential source of the useful information to recreate environment history of the individual fish in some of the species. In-depth study of the chemical composition of the otolith center (formed eaidy in fish life) and otolith edge (formed later in fish life) ensures chronological and environmental information stored in the otoliths [1]. This infoiTnation may be achieved by X-ray electron probe microanalysis (EPMA). EPMA is the analytical method to determine the elemental composition of different otolith s parts, their sizes varying from ten up to some tens of microns. 

The complex of the following destmctive and nondestmctive analytical methods was used for studying the composition of sponges inductively coupled plasma mass-spectrometry (ICP-MS), X-ray fluorescence (XRF), electron probe microanalysis (EPMA), and atomic absorption spectrometry (AAS). Techniques of sample preparation were developed for each method and their metrological characteristics were defined. Relative standard deviations for all the elements did not exceed 0.25 within detection limit. The accuracy of techniques elaborated was checked with the method of additions and control methods of analysis. 

Lauchli, A., Spurr, A.R. Wittkop, R.W. (1970). Electron probe analysis of freeze substituted, epoxy resin embedded tissue for ion transport studies in plants. Planta, 95, 341-50. 

In a study of dental silicate cements, Kent, Fletcher Wilson (1970) used electron probe analysis to study the fully set material. Their method of sample preparation varied slightly from the general one described above, in that they embedded their set cement in epoxy resin, polished the surface to flatness, and then coated it with a 2-nm carbon layer to provide electrical conductivity. They analysed the various areas of the cement for calcium, silicon, aluminium and phosphorus, and found that the cement comprised a matrix containing phosphorus, aluminium and calcium, but not silicon. The aluminosilicate glass was assumed to develop into a gel which was relatively depleted in calcium. 

Myelin in situ has a water content of about 40%. The dry mass of both CNS and PNS myelin is characterized by a high proportion of lipid (70-85%) and, consequently, a low proportion of protein (15-30%). By comparison, most biological membranes have a higher ratio of proteins to lipids. The currently accepted view of membrane structure is that of a lipid bilayer with integral membrane proteins embedded in the bilayer and other extrinsic proteins attached to one surface or the other by weaker linkages. Proteins and lipids are asymmetrically distributed in this bilayer, with only partial asymmetry of the lipids. The proposed molecular architecture of the layered membranes of compact myelin fits such a concept (Fig. 4-11). Models of compact myelin are based on data from electron microscopy, immunostaining, X-ray diffraction, surface probes studies, structural abnormalities in mutant mice, correlations between structure and composition in various species, and predictions of protein structure from sequencing information [4]. 

HN03. ICP-AES showed a wide variety of elements to be present with a particular build-up of cobalt, nickel and zinc (50-100 ppm). The presence of lead, cadmium and mercury at dangerously high levels was not indicated. Additional qualitative studies were made by electron probe analysis and ICP-MS. 

Gartner S, Le Faucheur L, Roinel N, Paris-Pireyre N. Preliminary studies on the elemental composition of xylem exudate from two varieties of wheat by electron probe analysis. Scanning Electron Microsc 1984 IV 1739-1744. 

Some of the disadvantages of the electron-probe method may be overcome, as in other methods, by the use of complementary techniques. Such techniques can complete the results obtained by electron microprobe. For instance, the introduction of a proton microprobe [39], which is much more sensitive (by two orders of magnitude) than the electron microprobe, and may be used with very good results in geochemical and cosmochemical studies. 

Lengyel and Kalman have reported an electron diffraction study of water 20>. The high energy electrons used permit the structure function to be probed at (large) values of s unattainable in either X-ray or neutron diffraction. This feature is valuable in that the wider the range of s for which data are available, the more accurate is the inversion of the observed h(s) to the direct space function h(R). Typical data, for D2O at 25 °C, are shown in Fig. 5. Note the similarities, and differences, between the electron diffraction, X-ray diffraction and neutron diffraction data. 

Antibiotic Mg complex induced alteration in the ultrastructural changes in the native and HI depleted chromatin were monitored by thermal melting analysis, polyacrylamide gel mobility assay, dynamic light scattering experiments and transmission electron microscopic studies. Micrococcal nuclease digestion is the biochemical probe to assess the accessibility of the antibiotic Mg + complexes to nucleosomal DNA. 

The first electron spectroscopic study of adsorbed hydrocarbons was that reported by Eastman and Demuth (78) who used He radiation to probe the valence electrons of benzene, acetylene, and ethylene. Figure 17 shows the difference spectrum of C2H4 adsorbed on Ni(lll) at 100 and 230 K compared with the results of Clarke et al. (79) for ethylene adsorption on Pt(lOO) at 290 K, propylene adsorption on Pt(lOO), and ethylene adsorption on Pt(lll). 

Accurate measurements of low order structure factors are based on the refinement technique described in section 4. Using the small electron probe, a region of perfect crystal is selected for study. The measurements are made by comparing experimental intensity profiles across CBED disks (rocking curves) with calculations, as illustrated in fig. 5. The intensity was calculated using the Bloch wave method, with structure factors, absorption coefficients, the beam direction and thickness treated as refinement parameters. 

Miura and Yoshida also investigated the changes in the microstructure of 1100 EW Nafion sulfonate membranes, in alkali, ammonium, and alkylammonium cation forms, that were induced by swelling in ethanol using DSC, dynamic mechanical analysis (DMA), SAXS, and electron probe microanalysis (EPMA). These studies were performed within the context of liquid pervaporation membranes that could potentially be used to separate ethanol from water... 

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