ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1974.tb03921.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

SUMMARYThe ToF atom‐probe FIM is a microanalytical tool of ultimate sensitivity. Design and performance of the three presently operating instruments are described, including applications to metallurgical problems and contributions to basic effects in field ion microscopy. Up to four‐fold ionic charges of metals, field adsorption of noble gases, and the occurrence of metal‐helide ions have been surprising results. The mass resolution of present atom‐probes is marginal due to random ion energy deficits. A new energy deficit compensated atom‐probe offers a very satisfactory mass resolution

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1974.tb03922.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

SUMMARYScanning electron microscopy is developing towards increased analytic capabilities such as characteristic X‐ray analysis as a routine adjunct to the topographic image. At the same time improved instrumentation will make higher resolution possible for both ultra‐thin and bulk specimens. Some of the newer techniques for specimen preparation are also no

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1974.tb03923.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1974.tb03924.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

SUMMARYFactors affecting the visibility of cell cytoplasmic structures and cell surface projections have been evaluated for examination of whole wet, unstained and unfixed cell preparations in the hydration chamber of a high voltage microscope.It was found that the thickness of the cells and that of the surrounding water layer were the most important factors affecting contrast and resolution of structures. One technique (surface spreading) flattened nuclei enough to see internal nuclear structure. Some washing and fixing (glutaraldehyde) methods caused regions of the grid of cultured cells to become hydrophobic with consequent improvement in contrast and resolution in these areas. Optimization of these factors appears feasible.The effects of cell freshness, blurring due to cell structure, vibration and Brownian movement, electron radiation and heat damage, microscope image mode, and photographic emulsion resolution are also discussed.Cell movements (e.g. cytoplasmic streaming) have not been observed to date, the possible reasons being radiation damage, cell bursting at lowered pressure, oxygen lack and concentration of metabolites on the grid surface.

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1974.tb03925.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

SUMMARYThe complementary replica technique for freeze‐etching was developed to help answer certain questions concerning fracture planes and contamination artefacts. In order to obtain this capability in our freeze‐etch laboratory we have chosen, for scientific as well as financial reasons, to adapt the Denton apposed specimen tooling to our already‐existing Balzers facilities. The method employed for this adaption and results obtained with it are reported h

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1974.tb03926.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

SUMMARYThe loss of mass from biological tissue sections during electron microprobe irradiation was observed by means of a silicon semiconductor detector set to record continuum X radiation. The rate of loss depended on several factors, conspicuously on specimen temperature. In accord with earlier observations with non‐focused beams, most of the ‘immediate’ loss occurred within an electron dose of the order of 10−

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1974.tb03927.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

SUMMARYAn apparatus for the rapid freezing of tissue is described, which can be used for the electron microscopy of arrested physiological processes. The material is frozen by bringing it in contact with a silver surface cooled to liquid nitrogen temperature at reduced pressure. The freezing surface is protected from condensation of moisture and gases from the air by a flow of helium gas. The cooling of the specimen during its descent through the cold helium is not large enough to interfere with physiological processes. Freezing occurs very rapidly in the surface but is retarded to about 8 msec at a depth of 10 μm. The apparatus was used to freeze frog muscle during contraction

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1974.tb03928.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

SUMMARYThe periodic acid‐silver methenamine method and the periodic acid‐thio‐carbohydrazide‐silver proteinate method have been used for the demonstration of carbohydrates in various plant and animal tissues. The comparison of the results obtained with both methods indicates that the periodic acid‐thiocarbohydrazide‐silver proteinate method is more specific and gives better quality pictures than the PA‐silver methenamine method. It is pointed out that adequate controls are necessary for a valid cytochemical interpretation of the results. With the PA‐thiocarbohydrazide‐silver proteinate method, no positively stained structure can be assumed to be of carbohydrate nature unless it is found unstained in non‐oxidized thiocarbohydrazide‐silver proteinate treated sections. Both methods have their limitations and do not demonstrate the total carbohydrate amou

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1974.tb03929.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

SUMMARYRed cells from metamorphosingXenopus laeviswere treated with a fluorescein‐conjugated guinea‐pig antibody toXenopustadpole haemoglobin, a rabbit antibody toXenopusadult haemoglobin, and a rhodamine‐conjugated goat anti‐rabbit globulin antibody. The presence of both red and green fluorescence in some cells indicated that at metamorphosis a proportion of the red cells contained both adult and tadpole haemo

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1974.tb03930.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY