X‐ray microanalysis of epon sections after oxygen plasma microincineration

Barnard, Tudor; Thomas, Richard S.

doi:10.1111/j.1365-2818.1978.tb00105.x

Cited by 13 publications

(6 citation statements)

References 17 publications

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“…In agreement with previous studies of 0 2 rf ED etching of other biological specimens (Barnard & Thomas, 1978;Johansson & Camner, 1979;Thomas, 1981 ;Thomas & Corlett, 1981), morphologic contrast and visualization of ultrastructural features by SEM is generally enhanced (Fig. 3).…”

Section: 2 Radiofrequency ( R F ) Electrodeless Discharge (Ed) Psupporting

confidence: 92%

“…There has been a burgeoning interest in the use of both plasma and ion beam etching techniques to modify the surface morphology and chemical composition of fixed biological tissues (Linton et al, 1982;Barnard & Thomas, 1978;Bendet & Rizk, 1976;Johansson & Camner, 1979;Thomas, 1981;Thomas & Corlett, 1981). In the instance of electron microscopy and associated analytical techniques, selective etching of embedded tissues can provide enhanced morphologic contrast and improved X-ray microanalysis.…”

Section: Introductionmentioning

confidence: 99%

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Ultrastructural comparison of ion beam and radiofrequency plasma etching effects on biological tissue sections

Linton

Farmer

Ingram

et al. 1984

Journal of Microscopy

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K E Y WORDS. Ion beam sputtering, plasma etching, SEM, TEM, ultrastructure, frog skeletal muscle, preferential sputtering, ion microanalysis, surface topography. SUMMARY Three dry etching techniques (Ar+ ion beam, Oz+ ion beam, 0 2 radiofrequency electrodeless discharge) were compared with respect to preferential etching and damage to the ultrastructure of glutaraldehyde-fixed Epon-embedded frog skeletal muscle sections. SEM and TEM studies were performed on both unstained and stained (osmium tetroxide, uranyl acetate) sections. Etching effects were observed to differ for the various ion beam or plasma etching techniques. Whereas selective retention of electron dense structures (e.g. Z lines, nuclear heterochromatin) was observed for oxygen plasma etching, preferential etching of these components was observed using Ozf ion beam bombardment. Selectively etched Z lines and etch-resistant nucleoli were observed for both reactive ( 0 2 + ) and inert (Ar+) ion beam sputtering after sufficiently high ion doses. The above suggest that selective etching under keV ion beam irradiation is related more to physical sputtering processes (momentum transfer) than to the chemical reactivity of the incident ion. Heavy metal post-fixation and staining had no qualitative effect on the nature of the selective etching phenomena. The above findings are significant in that they potentially influence both electron and ion microprobe measurements of etched biological specimens.

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Section: 2 Radiofrequency ( R F ) Electrodeless Discharge (Ed) Psupporting

confidence: 92%

Section: Introductionmentioning

confidence: 99%

Ultrastructural comparison of ion beam and radiofrequency plasma etching effects on biological tissue sections

Linton

Farmer

Ingram

et al. 1984

Journal of Microscopy

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“…In fact, to generate a usable number of X-rays, a large current is required in the electron beam, and for a conventional tungsten filament of low brightness this requires a large beam diameter. Actual measurements of spatial resolution of X-ray microanalysis on standard biological specimens in standard instruments are in the region of 0.1-0.5/~m (Barnard & Thomas, 1978;Marshall, 1980a;Sumner, 1981, and unpublished observations). This is, of course, similar to the resolution limit of the light microscope, and quite inadequate for true ultrastructural microanalysis.…”

Section: Spatial Resolutionmentioning

confidence: 96%

X-ray microanalysis: a histochemical tool for elemental analysis

1983

Histochem J

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The interactions of electrons with specimens Types of interactionsWhen electrons strike an object, as in an electron microscope, a number of interactions occur that can be, and are, used to give information about the specimen (Table 1). The various types of interactions of electrons that are used to produce images in scanning or transmission electron microscopes are familiar to most biologists, in the form of electron micrographs. The density of a transmission electron micrograph is dependent on the mass of the specimen at that point; because of this, staining and histochemical methods have been developed for electron microscopy using heavy metals. In scanning electron microscopy, the generation of back-scattered electrons is also dependent on atomic number. The information that can be obtained about the composition of the specimen in these ways is, however, extremely crude compared with that obtainable by some other methods. Among these other methods is X-ray microanalysis (also known as electron probe microanalysis) which is foremost among such techniques at present for ease of application and interpretation, and availability of commercial equipment. In X-ray microanalysis, the electrons striking the specimen excite X-rays characteristic of the elements in the specimen. X-ray microanalysis is thus a form of elemental analysis. It has been applied to a wide variety of biological problems, and these will be considered later in the section entitled Some biological applications of X-ray microanalysis. The production of X-rays by electronsWhen an electron of sufficient energy passes through the cloud of electrons surrounding an atomic nucleus, it may cause the displacement of an inner orbital electron to an orbit of higher energy. In the process the primary electron is inelastically scattered; that is, it

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“…megaterium spores in bulk; however, no X-ray microanalyses of single spores before and after low-temperature ashing are available. Low-temperature ashing has also been used as a preconcentration step for elemental detection and localization (Thomas 1974;Hohman 1974;Barnard and Thomas 1978;Brenna and Morrison 1984).…”

Section: Microincineration Mechanisms Of Sporesmentioning

confidence: 99%

“…Ashing generally increases elemental X-ray intensities of biological specimens (Albright and Lewis 1965;Hohman and Schraer 1972;Scherrer and Gerhardt 1972;Meyer and Stewart 1977; Barnard and Thomas 1978;Adamec et al 1979).…”

Section: Introductionmentioning

confidence: 98%

Microincineration and elemental X-ray microanalysis of single Bacillus cereus T spores

Scherrer¹,

Shull²

1987

Can. J. Microbiol.

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Single whole spores of bacillus cereus T were analyzed by scanning electron microscopy and electron microprobe X-ray microanalysis before and after high-temperature (600 degrees C) ashing in air. High-temperature ashing consisted of a centripetal oxidation of the spore surface combined with pyrolysis of the spore's interior. Ashing of single spores produced a compact central ash particle, mimicking the much larger unashed spore body in outline but containing craterlike microregions, and a peripheral thin ash film. Ashing mostly eliminated the spore's organic matrix; however, ash residues still gave residual carbon-characteristic X-ray counts. Ashing of single spores produced a two-, five-, and six-fold increase of potassium, magnesium, and calcium X-ray intensities, respectively. Iron, although low in actual counts, became detectable after ashing. Phosphorus characteristic X-rays were decreased by 41% after ashing, while volatilization lowered sodium and manganese X-ray intensities by over 80%. High-temperature ashing enhanced element-characteristic X-ray intensities of the non-volatilizable mineral(ized) elements of spores by compacting them into ash residues, more so than by simply abolishing their organic matrix. Microincineration appears a generally useful preconcentration technique for elemental detection and localization in X-ray microanalysis.

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X‐ray microanalysis of epon sections after oxygen plasma microincineration

Cited by 13 publications

References 17 publications

Ultrastructural comparison of ion beam and radiofrequency plasma etching effects on biological tissue sections

Ultrastructural comparison of ion beam and radiofrequency plasma etching effects on biological tissue sections

X-ray microanalysis: a histochemical tool for elemental analysis

Microincineration and elemental X-ray microanalysis of single Bacillus cereus T spores

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