Stereo imaging in the shadow electron microscope

Author(s):  
W. C. T. Dowell

Stereo imaging is not new to electron microscopy. Von Ardenne, who first published transmission pairs nearly forty hears ago, himself refers to a patent application by Ruska in 1934. In the early days of the electron microscope von Ardenne employed a pair of magnetic lenses to view untilted specimens but soon opted for the now standard technique of tilting the specimen with respect to the beam.In the shadow electron microscope stereo images can, of course, be obtained by tilting the specimen between micrographs. This obvious method suffers from the disadvantage that the magnification is very sensitive to small changes in specimen height which accompany tilting in the less sophisticated stages and it is also time consuming. A more convenient method is provided by horizontally displacing the specimen between micrographs. The specimen is not tilted and the technique is both simple and rapid, stereo pairs being obtained in less than thirty seconds.

1951 ◽  
Vol 29 (6) ◽  
pp. 491-494 ◽  
Author(s):  
William H. Barnes ◽  
Margaret S. Lambe

Experiments on the behavior of halides as shadow-casting agents in electron microscopy are described. The use of calcium fluoride, placed directly on the specimen screen, is suggested as a convenient method for routine qualitative shadowing of preparations in the preliminary stages of an electron microscopic study. No vacuum coating equipment is required.


Author(s):  
I. Yamamoto ◽  
B. Rosario

It is known that suitably buffered formaldehyde can be used as a killing agent and primary fixative for electron microscopy(Pease).We were interested in how long buffered formalin preserves tissue. Thus, in this study, an attempt was made to observe ultrastructure of surgical material fixed and stored in buffered formalin for a long time.Pieces of fresh tissues were, fixed in buffered formalin at 4°C for one hour, and then placed at room temparature for weeks and months without changing solution.Buffered formalin used was prepared as follows:A. “ reagent grade ” formalinB. 0.05 M Sorensen's phosphate buffer, pH 7.2-7.4 mix 1 part of A and 9 parts of B to make 10 % solution.Pieces of tissues were then minced and postfixed in 1 % osmic acid buffered with veronal acetate for two hours or more. Postfixed tissues were then embedded in an epoxy resin mixture through standard technique. Thin sections were stained with uranyl acetate followed by lead, and examined in a Hitachi 11C electron microscope.


Author(s):  
Linda M. Stannard ◽  
Margaret Lennon

Burnupena cincta and Fusus verruculatus are two whelks which inhabit the intertidal zones of the Cape Peninsula shore. Their respiratory pigments, or haemocyanins, are morphologically similar in structure (Figs. 1 and 2) and appear in the electron microscope as short cylindrical rods about 34 nm in diameter and 36 nm high. Viewed side-on the molecules show regular banding suggesting a structure composed of six equidistant rings of sub-units. Occasionally the particles have the appearance of possessing a central “belt” in the position of the 3rd and 4th rows of sub-units. End-on views of the haemocyanin molecules show a circular contour with a dense outer ring and a less dense inner ring in which 10 definite sub-units may frequently be distinguished. A number of molecules display an extra central inner component which appears either as a diffuse plug or as a discrete ring-shaped core ± 8 nm in diameter.


Author(s):  
O.C. de Hodgins ◽  
K. R. Lawless ◽  
R. Anderson

Commercial polyimide films have shown to be homogeneous on a scale of 5 to 200 nm. The observation of Skybond (SKB) 705 and PI5878 was carried out by using a Philips 400, 120 KeV STEM. The objective was to elucidate the structural features of the polymeric samples. The specimens were spun and cured at stepped temperatures in an inert atmosphere and cooled slowly for eight hours. TEM micrographs showed heterogeneities (or nodular structures) generally on a scale of 100 nm for PI5878 and approximately 40 nm for SKB 705, present in large volume fractions of both specimens. See Figures 1 and 2. It is possible that the nodulus observed may be associated with surface effects and the structure of the polymers be regarded as random amorphous arrays. Diffraction patterns of the matrix and the nodular areas showed different amorphous ring patterns in both materials. The specimens were viewed in both bright and dark fields using a high resolution electron microscope which provided magnifications of 100,000X or more on the photographic plates if desired.


Author(s):  
J. D. Hutchison

When the transmission electron microscope was commercially introduced a few years ago, it was heralded as one of the most significant aids to medical research of the century. It continues to occupy that niche; however, the scanning electron microscope is gaining rapidly in relative importance as it fills the gap between conventional optical microscopy and transmission electron microscopy.IBM Boulder is conducting three major programs in cooperation with the Colorado School of Medicine. These are the study of the mechanism of failure of the prosthetic heart valve, the study of the ultrastructure of lung tissue, and the definition of the function of the cilia of the ventricular ependyma of the brain.


Author(s):  
Lawrence W. Ortiz ◽  
Bonnie L. Isom

A procedure is described for the quantitative transfer of fibers and particulates collected on membrane filters to electron microscope (EM) grids. Various Millipore MF filters (Millipore AA, HA, GS, and VM; 0.8, 0.45, 0.22 and 0.05 μm mean pore size) have been used with success. Observed particle losses have not been size dependent and have not exceeded 10%. With fibers (glass or asbestos) as the collected media this observed loss is approximately 3%.


Author(s):  
E. U. Lee ◽  
P. A. Garner ◽  
J. S. Owens

Evidence for ordering (1-6) of interstitial impurities (O and C) has been obtained in b.c.c. metals, such as niobium and tantalum. In this paper we report the atomic and microstructural changes in an oxygenated c.p.h. metal (alpha titanium) as observed by transmission electron microscopy and diffraction.Oxygen was introduced into zone-refined iodide titanium sheets of 0.005 in. thickness in an atmosphere of oxygen and argon at 650°C, homogenized at 800°C and furnace-cooled in argon. Subsequently, thin foils were prepared by electrolytic polishing and examined in a JEM-7 electron microscope, operated at 100 KV.


Author(s):  
J. L. Farrant ◽  
J. D. McLean

For electron microscope techniques such as ferritin-labeled antibody staining it would be advantageous to have available a simple means of thin sectioning biological material without subjecting it to lipid solvents, impregnation with plastic monomers and their subsequent polymerization. With this aim in view we have re-examined the use of protein as an embedding medium. Gelatin which has been used in the past is not very satisfactory both because of its fibrous nature and the high temperature necessary to keep its solutions fluid. We have found that globular proteins such as the serum and egg albumins can be cross-linked so as to yield blocks which are suitable for ultrathin sectioning.


Author(s):  
H. Koike ◽  
S. Sakurai ◽  
K. Ueno ◽  
M. Watanabe

In recent years, there has been increasing demand for higher voltage SEMs, in the field of surface observation, especially that of magnetic domains, dislocations, and electron channeling patterns by backscattered electron microscopy. On the other hand, the resolution of the CTEM has now reached 1 ∼ 2Å, and several reports have recently been made on the observation of atom images, indicating that the ultimate goal of morphological observation has beem nearly achieved.


Author(s):  
Mircea Fotino

A new 1-MeV transmission electron microscope (Model JEM-1000) was installed at the Department of Molecular, Cellular and Developmental Biology of the University of Colorado in Boulder during the summer and fall of 1972 under the sponsorship of the Division of Research Resources of the National Institutes of Health. The installation was completed in October, 1972. It is installed primarily for the study of biological materials without many of the limitations hitherto unavoidable in standard transmission electron microscopy. Only the technical characteristics of the installation are briefly reviewed here. A more detailed discussion of the experimental program under way is being published elsewhere.


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