The energy filtering TEM (EFTEM) in modern biological transmisson Electron Microscopy

Author(s):  
W. Probst ◽  
V.E. Bayer

Modern biological electron microscopy can no longer be a static tool merely describing morphology. In addition to ultrastructural information, insights into the molecular and chemical composition of a sample are needed so that new findings stemming from molecular biological and biochemical analyses can be given meaning in an ultrastructural context. Biological electron microscopy will be an essential tool for future discoveries involving the ultrastructural localization of molecules and chemical elements, and it will provide a means to identify the ultrastructural basis for a variety of reaction mechanisms. Many messenger compounds are currently known which can produce dynamic changes of either a subtle or dramatic nature at the ultrastructural level, but only the most basic of these can be examined using a conventional transmission electron microscope (CTEM). CTEMs provide limited information because they perform conventional imaging and do not employ all the signals available for analysis. Unlike a CTEM, an EFTEM permits the selection of a defined energy (wavelength) of electrons which are then used for imaging.

Author(s):  
P. M. Lowrie ◽  
W. S. Tyler

The importance of examining stained 1 to 2μ plastic sections by light microscopy has long been recognized, both for increased definition of many histologic features and for selection of specimen samples to be used in ultrastructural studies. Selection of specimens with specific orien ation relative to anatomical structures becomes of critical importance in ultrastructural investigations of organs such as the lung. The uantity of blocks necessary to locate special areas of interest by random sampling is large, however, and the method is lacking in precision. Several methods have been described for selection of specific areas for electron microscopy using light microscopic evaluation of paraffin, epoxy-infiltrated, or epoxy-embedded large blocks from which thick sections were cut. Selected areas from these thick sections were subsequently removed and re-embedded or attached to blank precasted blocks and resectioned for transmission electron microscopy (TEM).


Author(s):  
L.E. Murr ◽  
A.B. Draper

The industrial characterization of the machinability of metals and alloys has always been a very arbitrarily defined property, subject to the selection of various reference or test materials; and the adoption of rather naive and misleading interpretations and standards. However, it seems reasonable to assume that with the present state of knowledge of materials properties, and the current theories of solid state physics, more basic guidelines for machinability characterization might be established on the basis of the residual machined microstructures. This approach was originally pursued by Draper; and our presentation here will simply reflect an exposition and extension of this research.The technique consists initially in the production of machined chips of a desired test material on a horizontal milling machine with the workpiece (specimen) mounted on a rotary table vice. A single cut of a specified depth is taken from the workpiece (0.25 in. wide) each at a new tool location.


Author(s):  
L. D. Peachey ◽  
J. P. Heath ◽  
G. Lamprecht

Biological specimens of cells and tissues generally are considerably thicker than ideal for high resolution transmission electron microscopy. Actual image resolution achieved is limited by chromatic aberration in the image forming electron lenses combined with significant energy loss in the electron beam due to inelastic scattering in the specimen. Increased accelerating voltages (HVEM, IVEM) have been used to reduce the adverse effects of chromatic aberration by decreasing the electron scattering cross-section of the elements in the specimen and by increasing the incident electron energy.


Author(s):  
R. J. Lauf ◽  
H. Keating

The preparation of fragmented or particulate ceramic materials for transmission electron microscopy (TEM) examination has traditionally been difficult, particularly if a durable, permanent specimen is desired. Furthermore, most established methods for dealing with micron- and submicron-sized samples (e.g., dispersion in plastic films) do not permit selection of orientations or ion thinning. A technique has been developed that is useful for a variety of materials, permits the selection of specimen orientation, is compatible with ion milling requirements, and produces a durable specimen that can be reexamined later if necessary.


2011 ◽  
Vol 17 (S2) ◽  
pp. 790-791
Author(s):  
M Watanabe ◽  
F Allen

Extended abstract of a paper presented at Microscopy and Microanalysis 2011 in Nashville, Tennessee, USA, August 7–August 11, 2011.


2012 ◽  
Vol 48 (9) ◽  
pp. 322-330 ◽  
Author(s):  
Shin HORIUTI ◽  
Takeshi HANADA ◽  
Takayuki MIYAMAE ◽  
Tadae YAMANAKA ◽  
Kogoro OOSUMI ◽  
...  

2001 ◽  
Vol 7 (S2) ◽  
pp. 1038-1039
Author(s):  
S. Raddatz ◽  
E. P. Mark ◽  
A. Haking ◽  
W. Probst ◽  
M. Wiessler ◽  
...  

A promising aspect of ESI is its application in the detection of elemental labels introduced into biomolecules for cell and molecular biological techniques. Even though colloidal gold labeling for electron microscopy (EM) is highly developed, availability of alternative labels, especially for double or triple labeling applications would be helpful because of difficulties with gold concerning i) detection (gold diameters ≤1nm), ii) discrimination due to gold particle size variations in one size class, and iii) different labeling efficiencies depending on gold granule size. An alternative labeling molecule should contain a high concentration of a specific chemical element which is not or in minor concentrations present in the system under surveillance, and has to have the potential to be discriminated from “biological” elements by ESI.With respect to ESI, one candidate for elemental labeling is boron. It meets the criteria described above and substantial experience in the synthesis of labeling compounds exists. From the chemical point of view, the preferred labeling structure is a so called dendrimer, a highly branched regular three-dimensional monodisperse macromolecule. Dendritic structures offer a large variety of functionalities to incorporate an element detectable by energy filtering transmission electron microscopy (EFTEM).


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