A Scanning and Transmission Electron Microscope Examination of ACTH-Induced ‘Rounding up’ in Triton X-100 Cytoskeleton Residues of Cultured Adrenal Cells

A transmission electron micrograph study indicates that the material identified as the centromere in gonial mitotic cells is more localized in the lepidopterans, Ephestia kuehniella (Zeller) and Trichoplusia ni (Hübner), than in the hemipteran, Oncopeutus fasciatus (Dallas). The lepidopteran centromeres are similar in size to the centromeres found in several monokinetic species. In O. fasciatus the mitotic nuclear envelope disappears while the E. kuehniella and T. ni nuclear envelopes persist during division. Factors other than the extent of the centromere material may be involved in making the Lepidoptera more resistant to radiation sterilization than the Hemiptera.

Download Full-text

Relation between internal boundaries and critical current in textured YBa2Cu3O7−δ: Transmission electron microscope observations

Journal of Materials Research ◽

10.1557/jmr.1998.0384 ◽

1998 ◽

Vol 13 (10) ◽

pp. 2800-2806 ◽

Cited By ~ 1

Author(s):

A. Khalfi ◽

G. Trolliard ◽

B. Soulestin ◽

D. S. Smith ◽

J. P. Bonnet ◽

...

Keyword(s):

Electron Microscope ◽

Critical Current ◽

Strong Coupling ◽

Transmission Electron Microscope ◽

Melting Zone ◽

Optical Microscope ◽

Microscope Examination ◽

Transmission Electron ◽

Superconducting Current ◽

Misorientation Angles

The local critical current (Ic) at 77 K measured at the mm scale in a 60 mm long sample of YBa2Cu3O7−δ prepared by a melting zone process is correlated to the microstructure. Lower values of Ic (<20 A) were obtained in a part of the sample which optical microscope examination showed to be generally polycrystalline. In contrast, the rest of the sample, consisting mostly of large textured domains, gave values for Ic of 120 A and above. Transmission electron microscope observations revealed that the textured domains contain internal boundaries. Depending on the scale of observation, the misorientation angles across the boundaries could vary from a few tenths of a degree up to a few degrees. This seems characteristic for boundaries in textured material which allow strong coupling of the superconducting current across themselves.

Download Full-text

Anatomy and Ultrastructure of Pith Fleck-Like Tissues in Some Rosaceae Tree Species

IAWA Journal ◽

10.1163/22941932-90001344 ◽

1994 ◽

Vol 15 (1) ◽

pp. 65-73 ◽

Cited By ~ 4

Author(s):

Danny Rioux

Keyword(s):

Aqueous Solution ◽

Electron Microscope ◽

Transmission Electron Microscope ◽

Tree Species ◽

Tissue Formation ◽

Microscope Examination ◽

Transmission Electron ◽

Cambial Zone ◽

Histochemical Tests ◽

Anatomy And Ultrastructure

Unusual xylem tissues were found in Amelanchier laevis, Prunus pensylvanica, P. virginiana, Sorbus americana and S. aucuparia. These zones of abnormal xylem were composed of hypertrophied cells and bands that apparently comprised collapsed cells. The hypertrophied cells appeared to occupy gaps that began to form in the cambial zone. Histochemical tests indicated that the bands were highly lignified and impermeable to an aqueous solution of KMnO4, as revealed by fluorescence. Transmission electron microscope examination disclosed clearly that the bands were composed of collapsed cells and showed that the hypertrophied cells had thicker walls which contained, at times, additional layers. Although the cause of this tissue formation is unknown, its anatomy is quite similar to pith fleck tissues reported by others as being caused by cambium mining insects.

Download Full-text

A Reproducible Selective Stain for Cardiac Sarcoplasmic Reticulum

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100051086 ◽

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.

Download Full-text

Surface Structure of the Spores of Glugea Weissenbergi

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010006310x ◽

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.

Download Full-text

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

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100062798 ◽

1969 ◽

Vol 27 ◽

pp. 176-177 ◽

Cited By ~ 1

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.

Download Full-text

X-ray microanalysis of thin specimens in the transmission electron microscope at voltages up to 1000 Kv.

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100109847 ◽

1978 ◽

Vol 36 (1) ◽

pp. 540-541

Author(s):

G. Cliff ◽

M.J. Nasir ◽

G.W. Lorimer ◽

N. Ridley

Keyword(s):

Electron Microscope ◽

Transmission Electron Microscope ◽

Weight Fraction ◽

Present Series ◽

Constant Independent ◽

X Ray ◽

Transmission Electron ◽

Series Of Experiments ◽

Image Position ◽

X Ray Absorption

In a specimen which is transmission thin to 100 kV electrons - a sample in which X-ray absorption is so insignificant that it can be neglected and where fluorescence effects can generally be ignored (1,2) - a ratio of characteristic X-ray intensities, I1/I2 can be converted into a weight fraction ratio, C1/C2, using the equationwhere k12 is, at a given voltage, a constant independent of composition or thickness, k12 values can be determined experimentally from thin standards (3) or calculated (4,6). Both experimental and calculated k12 values have been obtained for K(11<Z>19),kα(Z>19) and some Lα radiation (3,6) at 100 kV. The object of the present series of experiments was to experimentally determine k12 values at voltages between 200 and 1000 kV and to compare these with calculated values.The experiments were carried out on an AEI-EM7 HVEM fitted with an energy dispersive X-ray detector.

Download Full-text