Phase-contrast electron microscope lattice images of carbons

The direct visualization of crystal structure at "molecular" (ca 3Å) resolution has become a routine procedure in electron microscopy in the last few years for organic materials which are resistant to electron beam damage by virtue of π-electron derealization or electrical conductivity. More recently, similar images from an aliphatic material, i.e. the paraffin n-tetratetracontane, were published based on work with an electron microscope equipped with a He-cooled superconducting objective lens. Correlation-averaged electron images at 2.5A resolution were shown to correspond well to a theoretical image based on a multislice calculation for the known crystal structure and produced at the phase contrast transfer function of the electron microscope objective lens for the defocus value used in the experiment.

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Observation of biological macromolecules using various electron microscopic methods

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100081711 ◽

1978 ◽

Vol 36 (2) ◽

pp. 170-171

Author(s):

Mitsuo Ohtsuki ◽

Michael Sogard

Keyword(s):

Electron Microscope ◽

Phase Contrast ◽

Image Interpretation ◽

Density Lipoprotein ◽

Biological Macromolecules ◽

Contrast Effects ◽

Biological Structure ◽

Electron Microscopic ◽

Structural Investigations ◽

Staining Techniques

Structural investigations of biological macromolecules commonly employ CTEM with negative staining techniques. Difficulties in valid image interpretation arise, however, due to problems such as variability in thickness and degree of penetration of the staining agent, noise from the supporting film, and artifacts from defocus phase contrast effects. In order to determine the effects of these variables on biological structure, as seen by the electron microscope, negative stained macromolecules of high density lipoprotein-3 (HDL3) from human serum were analyzed with both CTEM and STEM, and results were then compared with CTEM micrographs of freeze-etched HDL3. In addition, we altered the structure of this molecule by digesting away its phospholipid component with phospholipase A2 and look for consistent changes in structure.

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The Imaging of Crystal Structures and Crystal Defects

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100069995 ◽

1978 ◽

Vol 36 (3) ◽

pp. 207-217

Author(s):

J.M. Cowley

Keyword(s):

Electron Microscope ◽

Crystal Structures ◽

Phase Contrast ◽

Crystal Defects ◽

Atom Density ◽

Lack Of Information ◽

Spatial Frequencies

The problem of "understandinq" electron microscope imaqes becomes more acute as the resolution is improved. The naive interpretation of an imaqe as representinq the projection of an atom density becomes less and less appropriate. We are increasinqly forced to face the complexities of coherent imaqinq of what are essentially phase objects. Most electron microscopists are now aware that, for very thin weakly scatterinq objects such as thin unstained bioloqical specimens, hiqh resolution imaqes are best obtained near the optimum defocus, as prescribed by Scherzer, where the phase contrast imaqe qives a qood representation of the projected potential, apart from a lack of information on the lower spatial frequencies. But phase contrast imaqinq is never simple except in idealized limitinq cases.

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Observation of Phase Contrast Images in STEM and CTEM Modes by Using 100 kV Field Emission Electron Gun

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100051967 ◽

1974 ◽

Vol 32 ◽

pp. 390-391

Author(s):

Y. Harada ◽

T. Goto ◽

H. Koike ◽

T. Someya

Keyword(s):

Field Emission ◽

Phase Contrast ◽

Image Formation ◽

Fresnel Diffraction ◽

Experimental Results ◽

Electron Gun ◽

Scanning Microscopy ◽

Emission Electron ◽

Lattice Images

Since phase contrasts of STEM images, that is, Fresnel diffraction fringes or lattice images, manifest themselves in field emission scanning microscopy, the mechanism for image formation in the STEM mode has been investigated and compared with that in CTEM mode, resulting in the theory of reciprocity. It reveals that contrast in STEM images exhibits the same properties as contrast in CTEM images. However, it appears that the validity of the reciprocity theory, especially on the details of phase contrast, has not yet been fully proven by the experiments. In this work, we shall investigate the phase contrast images obtained in both the STEM and CTEM modes of a field emission microscope (100kV), and evaluate the validity of the reciprocity theory by comparing the experimental results.

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Phase Contrast Aberration Corrected Electron Microscope for Phase Plate Imaging

Microscopy and Microanalysis ◽

10.1017/s1431927610057740 ◽

2010 ◽

Vol 16 (S2) ◽

pp. 534-535 ◽

Cited By ~ 2

Author(s):

E Majorovits ◽

B Barton ◽

G Benner ◽

C Dietl ◽

W Kühlbrandt ◽

...

Keyword(s):

Electron Microscope ◽

Phase Contrast ◽

Phase Plate ◽

Aberration Corrected

Extended abstract of a paper presented at Microscopy and Microanalysis 2010 in Portland, Oregon, USA, August 1 – August 5, 2010.

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THE SUBMICROSCOPIC ORGANIZATION OF AXON MATERIAL ISOLATED FROM MYELIN NERVE FIBERS

Journal of Experimental Medicine ◽

10.1084/jem.98.3.269 ◽

1953 ◽

Vol 98 (3) ◽

pp. 269-276 ◽

Cited By ~ 20

Author(s):

E. De Robertis ◽

C. M. Franchi

Keyword(s):

Electron Microscopy ◽

Electron Microscope ◽

Phase Contrast ◽

Nerve Fibers ◽

Myelinated Nerve ◽

Myelinated Nerve Fibers ◽

Dense Granules ◽

Small Clusters ◽

Membranous Material ◽

The Way

A technique has been developed for the extrusion of axon material from myelinated nerve fibers. This material is then compressed and prepared for observation with the electron microscope. All the stages of preparation and purification of the axon material can be checked microscopically and in the present paper they are illustrated with phase contrast photomicrographs. Observation with the electron microscope of the compressed axons showed the presence of the following components: granules, fibrils, and a membranous material. Only the larger granules could be seen with the ordinary microscope. A considerable number of dense granules were observed. Of these the largest resemble typical mitochondria of 250 mµ by 900 mµ. In addition rows or small clusters of dense granules ranging in diameter from 250 to 90 mµ were present. In several specimens fragments of a membrane 120 to 140 A thick and intimately connected with the axon were found. The entire axon appeared to be constituted of a large bundle of parallel tightly packed fibrils among which the granules are interspersed. The fibrils are of indefinite length and generally smooth. They are rather labile structures, less resistant in the rat than in the toad nerve. They varied between 100 and 400 A in diameter and in some cases disintegrated into very fine filaments (less than 100 A thick). The significance is discussed of the submicroscopic structures revealed by electron microscopy of the material prepared in the way described.

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High Resolution Lattice Images of G.P.Zones and Solute Clusters in Al-Cu and Cu-Be Alloys

MRS Proceedings ◽

10.1557/proc-21-131 ◽

1982 ◽

Vol 21 ◽

Cited By ~ 1

Author(s):

H. Yoshida ◽

H. Hashimoto ◽

Y. Yokota ◽

M. Takeda

Keyword(s):

Electron Microscope ◽

High Resolution ◽

Atomic Structures ◽

Resolution Electron ◽

Microscope Images ◽

Lattice Images ◽

Lattice Planes

ABSTRACTAtomic structures of G.P. zones and solute clusters in Al-Cu and Cu-Be alloys are studied by the atom resolution electron microscope images. The images of plate-like G.P. zones appear as dotted images with various brightnesses along (200) lattice planes. The solute clusters are also observed along (111) lattice planes.

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On Bridging the Gap in Cytology Between the Light and Electron Microscopes by Some Combined Observations on Snail Neurones

Journal of Cell Science ◽

10.1242/jcs.s3-105.70.139 ◽

1964 ◽

Vol s3-105 (70) ◽

pp. 139-162

Author(s):

S. M. McGEE-RUSSEL

Keyword(s):

Electron Microscope ◽

Phase Contrast ◽

Nile Blue ◽

Ultra Violet ◽

Object A ◽

Snail Neurones ◽

Cross Correlations ◽

Electron Microscopes ◽

Microscopy Data ◽

Dark Ground

Discrepancies between observations made with the light microscope only, and with the electron microscope only, can be clarified by using both instruments to study exactly the same section of the same object. A simple technique for doing this is outlined. Direct, phase-contrast, ‘anoptral’ phase-contrast, dark-ground, interference, and ultra-violet microscopy can all be used. When applied to snail neurones this technique of combined observations reveals intracellular organelles which have not previously been differentiated. These organelles are positively identified by criteria appropriate to each instrument. By combined observations it is possible to see the ‘Golgi apparatus’ in preparations stained only with Nile blue, by direct microscopy. Data obtained by combined observations are considered in relation to the previous literature. Unequivocal cross-correlations between the light and the electron microscope go a long way towards explaining past difficulties.

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