Energy-Filtered Electron Microscopy (EFEM) of Frozen Hydrated Biological Specimens
| العنوان: | Energy-Filtered Electron Microscopy (EFEM) of Frozen Hydrated Biological Specimens |
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| المؤلفون: | Erhard Zellmann, Wolfgang Probst, Richard Bauer |
| المصدر: | Proceedings, annual meeting, Electron Microscopy Society of America. 48:274-275 |
| بيانات النشر: | Cambridge University Press (CUP), 1990. |
| سنة النشر: | 1990 |
| مصطلحات موضوعية: | Frozen hydrated, Biological specimen, Materials science, law, Analytical chemistry, General Medicine, Electron microscope, law.invention |
| الوصف: | The preparation of hydrated biological specimens for the use in a TEM has made a great stride foreward due to the work of Dubochet et al. on vitrification and Muller et al. on high pressure freezing. Transfer units and cryo stages for the microscopes allow imaging of specimens in the 100K range. Due to simple physical reasons, however, contrast of such kinds of specimen is still a problemm in conventional transmission electron microscopes (CTEM). Solutions as they are provided by an EFEM will be shown and explained in the following.Ice is the main constituent of frozen hydrated specimens. The large ratio of inelastic-to-elastic total cross section of 4.0 in case of ice which is even more than that for carbon results in an unavoidable high amount of inelastically scattered electrons. Blurred images and lacking contrast are due to that fact. The EEL spectra from a frozen hydrated section of biological material before and after freeze drying in the microscope document this fact. (Figure 1). Increased scattering probability and thickness contribute to the inelastic loss. In Figure 2 the EEL spectrum from a thin pure ice layer without any support is compared to the spectrum from thin freeze dried cryo section on a thin support. In case of ice the maximum of the low loss range is clearly shifted towards zero loss, mainly due to oxygen low loss and plasmon and to hydrogen core loss. Thus for the images shown in the following Figures a narrow energy window of 10 eV is used really to cut off all the inelastically scattered electrons. |
| تدمد: | 2690-1315 0424-8201 |
| الوصول الحر: | https://explore.openaire.eu/search/publication?articleId=doi_________::e9eefa7d5ef4389b1776bdf7fbd2b1adTest https://doi.org/10.1017/s0424820100180124Test |
| حقوق: | CLOSED |
| رقم الانضمام: | edsair.doi...........e9eefa7d5ef4389b1776bdf7fbd2b1ad |
| قاعدة البيانات: | OpenAIRE |
| تدمد: | 26901315 04248201 |
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