scholarly journals Observations of Microcrystalline Plagioclase Spherulites With the Transmission Electron Microscope

1982 ◽  
Vol 5 (1) ◽  
pp. 63-70
Author(s):  
R. Mark Bailey ◽  
H. R. Wenk
Keyword(s):  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
Fiber Diameter ◽  
Growth Direction ◽  
Fiber Axis ◽  
Constant Thickness ◽  
Fiber Morphology ◽  
Thin Sections ◽  
C Fibers ◽  
Transmission Electron

Two thin sections of macroscopic plagioclase spherulites of approximately 1 cm diameter found in a rhyolitic glass have been studied with the transmission electron microscope (TEM). Orientations of the thin sections were chosen to give views down and perpendicular to the major fiber axis. The crystalline fiber phase is high albite microtwinned on the (010) composition plane, elongated in the major growth direction, [001]. Fiber morphology is non-polygonal with an average fiber diameter of 2000 Å perpendicular to c*. Fibers are separated by a non-crystalline residuum layer of approximately constant thickness (300–500 Å). Microtwinning relationships, as well as selected area diffraction (SAD) patterns, reveal both crystallographic and non-crystallographic branching with the former unexpectedly dominant.

Thin-section photomicrography

1992 ◽  
Vol 50 (2) ◽  
pp. 970-971
Author(s):  
Jack Holm ◽  
Rachel Goss
Keyword(s):  
Electron Microscope ◽  
Image Quality ◽  
Light Microscopy ◽  
Transmission Electron Microscope ◽  
Fundamental Problem ◽  
Depth Of Field ◽  
Large Section ◽  
Thin Sections ◽  
Transmission Electron ◽  
Conventional Light Microscopy

A fundamental problem in conventional light microscopy has long been the lack of image quality brought about by the use of sections which are thicker than the depth of field (DOF) of the microscope. These sections are used because “paraffin & steel” microtomy techniques preclude sections thinner than a few microns. The transmission electron microscope, however, requires section thicknesses of less than a micron. This requirement has resulted in the development of “epoxy & glass” microtomy techniques, and the ability to cut sections as thin as a few hundred Ångstroms. These thin sections are not routinely used for light microscopy because of the difficulty of preparation, the need for large section areas, and because of photomicrographic problems. The first two reasons may inhibit the use of thin sections in some situations, but the photomicrographic problems are surmountable.There is some disagreement in the literature regarding the actual DOF in photomicrographic situations.

Characterization of beam-induced thinning and shrinkage of semi-thick sections in the HVEM

1990 ◽  
Vol 48 (3) ◽  
pp. 752-753
Author(s):  
J.R. Kremer ◽  
E.T. O'Toole ◽  
G.P. Wray ◽  
D.M. Mastronarde ◽  
S.J. Mitchell ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
Colloidal Gold ◽  
Similar Data ◽  
Thin Sections ◽  
Gold Particles ◽  
Dose Rates ◽  
Transmission Electron ◽  
Conventional Transmission Electron Microscope

It is well known that irradiation of plastic sections in a conventional transmission electron microscope (cTEM) causes specimen thinning and distortion. Thinning has been observed in the cTEM using several embedding media, using methods such as shrinkage of ordered paracrystalline structures, and shrinkage of sections coated with colloidal gold markers. The total thinning observed in the cTEM (80kev) is 30-50% for thin sections of epon araldite, but similar data do not exist for the HVEM at 1000 kev. Here we describe beam induced thinning and shrinkage of 0.2um sections in the HVEM.Experiments were performed using 0.2um sections of EPOX 812/Araldite or LX112 with 15 nm and 30 nm gold particles affixed to either surface of the section. The sections were initially tilted to approximately 25° and irradiated with known dose rates. Micrographs were taken at different times between 0-20 minutes then the sections were tilted back to 0° for a reference micrograph.

Scanning transmission electron microscopy and X-ray microanalysis of unstained biological thin sections

1978 ◽  
Vol 36 (2) ◽  
pp. 110-111
Author(s):  
R. Freeman ◽  
G.W. Griffiths ◽  
A. V. Jones ◽  
K.R. Leonard
Keyword(s):  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
Collection Efficiency ◽  
Individual Element ◽  
Fresh Tissue ◽  
Thin Sections ◽  
X Ray ◽  
Scanning Transmission Electron ◽  
Transmission Electron ◽  
Scanning Transmission

The scanning transmission electron microscope (STEM) has two distinct advantages over the conventional transmission electron microscope (CTEM) for the investigation of low contrast specimens such as unstained thin sections. These are the much higher collection efficiency for scattered electrons and the possibility of electronic enhancement of the image forming signal. The addition of an X-ray analysis system to STEM may also enable the identification of some of the elements contributing to the overall image contrast and to detect individual element concentrations in features of high contrast occurring in the specimens.Fresh tissue was fixed in 1-2.5% glutaraldehyde in PIPES buffer, quickly dehydrated in ethanol and embedded in epon. Thin (silver/grey) sections were collected on carbon coated copper or nylon grids and viewed in the STEM without further treatment. The microscope used was a Vacuum Generators HB5 STEM with field emission source operating at lOOkV with simultaneous bright field (BF) and dark field (DF) detection systems.

scholarly journals In situ Generation of Ruthenium Tetroxide and Osmium Tetroxide for the Physical Sciences and Their Reaction Indicators

2002 ◽  
Vol 10 (5) ◽  
pp. 20-23
Author(s):  
Paul Beauregard
Keyword(s):  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
Osmium Tetroxide ◽  
Physical Sciences ◽  
Thin Sections ◽  
Ruthenium Tetroxide ◽  
Transmission Electron ◽  
In Situ Generation

Recently, there was a suggestion on the MSA listserver about the use of osmium tetroxide (OsO4 and how to handle it. One suggestion was that ampoules be scored, placed in a glass jar, and the ampoule smashed to release the contents. This seemed like a very unsafe way to use osmium tetroxide or ruthenium tetroxide. The purpose of this article is to suggest a way to generate smaller amounts of these compounds in a safer manner than smashing ampoules and wondering about what to do with the unused portion after staining or storing. Another purpose is to discuss a new reaction indicator for mainly osmium tetroxide. The use of a reaction specific indicator was mandatory for judging the level or degree to which staining had proceeded in thin sections for the transmission electron microscope (TEM).

A Reproducible Selective Stain for Cardiac Sarcoplasmic Reticulum

1974 ◽  
Vol 32 ◽  
pp. 214-215
Author(s):  
R. A. Waugh ◽  
J. R. Sommer
Keyword(s):  
Complex System ◽  
Electron Microscope ◽  
Sarcoplasmic Reticulum ◽  
Transmission Electron Microscope ◽  
Electron Microscopic ◽  
Cardiac Sarcoplasmic Reticulum ◽  
Transmission Electron

Cardiac sarcoplasmic reticulum (SR) is a complex system of intracellular tubules that, due to their small size and juxtaposition to such electron-dense structures as mitochondria and myofibrils, are often inconspicuous in conventionally prepared electron microscopic material. This study reports a method with which the SR is selectively “stained” which facilitates visualizationwith the transmission electron microscope.

Surface Structure of the Spores of Glugea Weissenbergi

1969 ◽  
Vol 27 ◽  
pp. 238-239
Author(s):  
Sanford H. Vernick ◽  
Anastasios Tousimis ◽  
Victor Sprague
Keyword(s):  
Electron Microscope ◽  
Surface Structure ◽  
Transmission Electron Microscope ◽  
Mature Spore ◽  
Spore Surface ◽  
Sectioned Material ◽  
Transmission Electron ◽  
Surface Detail

Recent electron microscope studies have greatly expanded our knowledge of the structure of the Microsporida, particularly of the developing and mature spore. Since these studies involved mainly sectioned material, they have revealed much internal detail of the spores but relatively little surface detail. This report concerns observations on the spore surface by means of the transmission electron microscope.

A New High Resolution Transmission Electron Microscope with Second-Zone Objective Lens

1969 ◽  
Vol 27 ◽  
pp. 176-177 ◽  
Author(s):  
H. Tochigi ◽  
H. Uchida ◽  
S. Shirai ◽  
K. Akashi ◽  
D. J. Evins ◽  
...  
Keyword(s):  
Electron Microscope ◽  
High Resolution ◽  
Transmission Electron Microscope ◽  
Objective Lens ◽  
High Excitation ◽  
Transmission Electron ◽  
New Instrument

A New High Excitation Objective Lens (Second-Zone Objective Lens) was discussed at Twenty-Sixth Annual EMSA Meeting. A new commercially available Transmission Electron Microscope incorporating this new lens has been completed.Major advantages of the new instrument allow an extremely small beam to be produced on the specimen plane which minimizes specimen beam damages, reduces contamination and drift.

SEM Examination of a Used Diamond Knife

1971 ◽  
Vol 29 ◽  
pp. 452-453
Author(s):  
J. Temple Black
Keyword(s):  
Electron Microscope ◽  
High Voltage ◽  
High Magnification ◽  
Metallic Materials ◽  
Wide Spread ◽  
Thin Sections ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Scanning Electron ◽  
Diamond Knife

Since its introduction by Fernandez-Moran, the diamond knife has gained wide spread usage as a common material for cutting of thin sections of biological and metallic materials into thin films for examination in the transmission electron microscope. With the development of high voltage E.M. and scanning transmission E.M., microtomy applications will become increasingly important in the preparation of specimens. For those who can afford it, the diamond knife will thus continue to be an important tool to accomplish this effort until a cheaper but equally strong and sharp tool is found to replace the diamond, glass not withstanding.In Figs. 1 thru 3, a first attempt was made to examine the edge of a used (β=45°) diamond knife by means of the scanning electron microscope. Because diamond is conductive, first examination was tried without any coating of the diamond. However, the contamination at the edge caused severe charging during imaging. Next, a thin layer of carbon was deposited but charging was still extensive at high magnification - high voltage settings. Finally, the knife was given a light coating of gold-palladium which eliminated the charging and allowed high magnification micrographs to be made with reasonable resolution.

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