A Comparative Study of Fractographic Replicas

1974 ◽  
Vol 32 ◽  
pp. 566-567
Author(s):  
Loren Anderson ◽  
Pat Pizzo ◽  
Glen Haydon
Keyword(s):  
Electron Microscopy ◽  
Electron Microscopic Examination ◽  
Direct Examination ◽  
Electron Microscopic ◽  
Reliable Technique ◽  
Service Failures ◽  
Transmission Electron ◽  
Mode Of Failure ◽  
Scanning Electron Microscopic ◽  
Scanning Electron

Transmission electron microscopy of replicas has long been used to study the fracture surfaces of components which fail in service. Recently, the scanning electron microscope (SEM) has gained popularity because it allows direct examination of the fracture surface. However, the somewhat lower resolution of the SEM coupled with a restriction on the sample size has served to limit the use of this instrument in investigating in-service failures. It is the intent of this paper to show that scanning electron microscopic examination of conventional negative replicas can be a convenient and reliable technique for determining mode of failure.

A comparison of the effects of several antifungal imidazole derivatives and polyenes on Candida albicans: an ultrastructural study by scanning electron microscopy

1982 ◽  
Vol 28 (10) ◽  
pp. 1119-1126 ◽  
Author(s):  
M. Bastide ◽  
S. Jouvert ◽  
J.-M. Bastide
Keyword(s):  
Electron Microscopy ◽  
Cell Wall ◽  
Candida Albicans ◽  
Cytoplasmic Membrane ◽  
Electron Microscopic Examination ◽  
Yeast Cells ◽  
Electron Microscopic ◽  
Imidazole Derivatives ◽  
Scanning Electron Microscopic ◽  
Scanning Electron

The early events in the interaction of two polyene (amphotericin B and nystatin) and five imidazole (clotrimazole, ketoconazole, miconazole, isoconazole, and econazole) antimycotics used at fungicidal concentrations with the surface of Candida albicans were studied by scanning electron microscopic examination of treated intact young yeast cells, treated spheroplasts, and spheroplasts liberated from treated young yeast cells. In all cases, treatment lasted 2 h. The polyenes passed through the yeast cell wall and interacted with the cytoplasmic membrane causing the spheroplasts to lose their characteristic spheric form and to liberate their contents. Clotrimazole caused the formation of numerous circular openings in the cytoplasmic membrane, but only when the agent was used to treat spheroplasts directly. Ketoconazole, miconazole, isoconazole, and econazole interacted with the cell wall causing formation of convolutions and wrinkles. The three imidazole derivatives that are structurally closely related, miconazole, isoconazole, and econazole, inhibited the enzyme-catalyzed release of spheroplasts from young yeast cells.

scholarly journals Scanning Electron Microscopic Study of Modified Chloroplasts in Senescing Broccoli Florets

HortScience ◽  
2000 ◽  
Vol 35 (1) ◽  
pp. 99-103 ◽  
Author(s):  
Hirofumi Terai ◽  
Alley E. Watada ◽  
Charles A. Murphy ◽  
William P. Wergin
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Light Microscopy ◽  
Structural Changes ◽  
Freeze Fracture ◽  
Electron Microscopic ◽  
Transmission Electron ◽  
Scanning Electron Microscopic Study ◽  
Scanning Electron Microscopic ◽  
Scanning Electron

Structural changes in chloroplasts of broccoli (Brassica oleracea L., Italica group) florets during senescence were examined using light microscopy, scanning electron microscopy (SEM) with freeze-fracture technique, and transmission electron microscopy (TEM) to better understand the process of chloroplast degradation, particularly at the advanced stage of senescence. Light microscopy revealed that chloroplasts, which initially were intact and green, became obscure in shape, and their color faded during senescence. Small, colored particles appeared in cells as the florets approached the final stage of senescence and became full- to dark-yellow in color. Scanning electron microscopy showed that stroma thylakoids in the chloroplast initially were parallel to each other and grana thylakoids were tightly stacked. As senescence advanced, the grana thylakoids degenerated and formed globules. The globules became larger by aggregation as senescence progressed, and the large globules, called “thylakoid plexus,” formed numerous vesicles. The vesicles ultimately were expelled into the cytosol, and the light microscope revealed many colored particles in the senescent cells. These results indicate that the degradation of chloroplasts in broccoli florets progresses systematically, with the final product being colored particles, which are visible in yellow broccoli sepal cells.

A scanning electron microscopic method for assessing surface topography of bladders

1984 ◽  
Vol 42 ◽  
pp. 40-41
Author(s):  
Betty I. Tarnowski ◽  
Gregory R. Schonbaum
Keyword(s):  
Electron Microscopy ◽  
Electron Microscopic ◽  
Transmission Electron ◽  
Step Procedure ◽  
Critical Point Drying ◽  
Scanning Electron Microscopic ◽  
Sampling Procedures ◽  
Electron Microscopic Method ◽  
Scanning Electron ◽  
Sem Analyses

Neither light microscopy nor transmission electron microscopy lend themselves to an accurate assessment of focal changes of epithelium: both techniques are limited by sampling procedures. The same limitation, however, does not apply to scanning electron microscopy (SEM) (1,2) which permits statistically meaningful analyses on a larger number of samples. The usefulness of such an approach was explored in our studies on the induction of damage to rat urothelium by cyclophosphamide (3,4) and its prevention by adjunct therapy with 2,3-dimercaptopropane sulfonate (DMPS). Portions of the bladder were sampled from the dome, central region and trigone and the tissue was prepared for SEM by dehydration in acetone, followed by critical point drying and gold coating. SEM analyses were performed in a two-step procedure using a Novascan scanning electron microscope at low (20X) and high (100X) magnifications.

Scanning Electron Microscopic Examination of Nonbeating Cilia

1982 ◽  
Vol 91 (6) ◽  
pp. 612-614 ◽  
Author(s):  
James P. Dudley ◽  
Lance Eisner ◽  
James D. Cherry
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Electron Microscopic Examination ◽  
Organ Cultures ◽  
Electron Microscopic ◽  
Scanning Electron Microscopic ◽  
Respiratory Membrane ◽  
Additional Role ◽  
Scanning Electron

When cilia stop beating, their role in moving mucus ceases, but it is uncertain if nonmotile cilia preserve their external architecture and are thus capable of maintaining an additional role of retarding microbial access to the cell. Cilia of chicken embryo tracheal organ cultures were observed until their activity stopped. When examined with scanning electron microscopy, ciliary axonemes did not appear to differ significantly from normally functioning cilia when observed at lower magnifications. Since their density can remain essentially unchanged, nonbeating cilia may still have a role in protecting respiratory membrane from toxic microorganisms.

A Scanning Electron Microscopic Study of the Nephrotic Kidney

1974 ◽  
Vol 32 ◽  
pp. 10-11
Author(s):  
Peter M. Andrews
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Electron Microscopic ◽  
Vascular Perfusion ◽  
Transmission Electron ◽  
Scanning Electron Microscopic Study ◽  
Scanning Electron Microscopic ◽  
Aminonucleoside Nephrosis ◽  
Scanning Electron

Scanning electron microscopy, supplemented with light microscopy and transmission electron microscopy, was used to study aminonucleoside nephrosis in rats. Aminonucleoside nephrosis was induced by daily injections of puromycin aminonucIeoside (1.5 mg/10 gm). When the rats exhibited considerable proteinuria (10 mg/ml after 14 days of injections), their kidneys were fixed by vascular perfusion, sectioned and critical point dried.

A Scanning Electron Microscopic Study of the Uriniferous Tubules

1973 ◽  
Vol 31 ◽  
pp. 622-623
Author(s):  
Peter M. Andrews
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Renal Glomerulus ◽  
Electron Microscopic ◽  
Vascular Perfusion ◽  
Scanning Electron Microscopic Study ◽  
Scanning Electron Microscopic ◽  
Collecting Tubules ◽  
Bowman's Capsule ◽  
Scanning Electron

Although there have been a number of recent scanning electron microscopic reports on the renal glomerulus, the advantages of scanning electron microscopy have not yet been applied to a systematic study of the uriniferous tubules. In the present investigation, scanning electron microscopy was used to study the ultrastructural morphology of the proximal, distal, thin loop, and collecting tubules. Material for observation was taken from rat kidneys which were fixed by vascular perfusion, sectioned by either cutting or fracturing technigues, and critically point dried.The brush border characterising proximal tubules is first detected on the luminal surface of Bowman's capsule adjacent to the urinary pole orifice. In this region one frequently finds irregular microvilli characterized by broad and flattened bases with occasional bulbous structures protruding from their surfaces.

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