The Use of Critical Point Phenomena in Preparing Specimens for the Electron Microscope

1950 ◽  
Vol 21 (7) ◽  
pp. 724-724 ◽  
Author(s):  
Thomas F. Anderson
Keyword(s):  
Electron Microscope ◽  
Critical Point ◽  
Critical Point Phenomena

Magnetostatic critical-point phenomena of Fe

1997 ◽  
Vol 82 (11) ◽  
pp. 5658-5661 ◽  
Author(s):  
Toshiro Tanaka ◽  
Kazuo Miyatani
Keyword(s):  
Critical Point ◽  
Critical Point Phenomena

Pulmonary microcirculation: tubules rather than sheet and post

1982 ◽  
Vol 53 (2) ◽  
pp. 510-515 ◽  
Author(s):  
W. G. Guntheroth ◽  
D. L. Luchtel ◽  
I. Kawabori
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Critical Point ◽  
Ringer Solution ◽  
Basic Component ◽  
Pulmonary Vasculature ◽  
Critical Point Drying ◽  
Pulmonary Microcirculation ◽  
Scanning Electron

We examined latex casts of the pulmonary microcirculation with the scanning electron microscope (SEM). Mature rats were anesthetized and ventilated; the pulmonary vasculature was washed out with lactated Ringer solution and then filled with a mixture of Geon latexes. The airways were filled with glutaraldehyde with resulting transmural vascular pressures of 10 cmH2O. After critical-point drying and corrosive removal of the lung tissue, SEM studies of the vascular replicas revealed two distinct patterns of pulmonary microcirculation: 1) sparse, long, tubular capillaries that comprise the thin subpleural layer and appear as “filler” in the peribronchial spaces; and 2) alveolar microcirculation that is composed of tightly matted, intersecting tubules, shorter but of the same diameter as type 1, in spherical array in two layers. The alveolar capillaries at low magnification appear superficially as sheets; however, the detailed morphology is not consistent with the sheet-and-post model. We conclude that the basic component of the pulmonary microcirculation is tubular and not different from other capillary beds except in density.

A comparison of microstructures of Cheddar cheese curd manufactured with calf rennet, bovine pepsin, and porcine pepsin

1976 ◽  
Vol 43 (1) ◽  
pp. 113-115 ◽  
Author(s):  
M. F. Eino ◽  
D. A. Biggs ◽  
D. M. Irvine ◽  
D. W. Stanley
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Critical Point ◽  
Cheddar Cheese ◽  
Microscope Examination ◽  
Porcine Pepsin ◽  
Electron Microscope Examination ◽  
Critical Point Drying ◽  
Cheese Curd ◽  
Scanning Electron

SummaryCalf rennet, bovine pepsin, and porcine pepsin were used to produce cheese curd, using the same milk and lactic culture for each. Specimens were prepared for scanning electron microscope examination by a modified critical-point drying technique.From examination of the micrographs, the curd made with bovine and porcine pepsin were similar in structure and in orientation of the coagulated protein, whereas the curd produced with rennet was different, having a more compact and organized structure.

scholarly journals THE STRANDEDNESS OF MEIOTIC CHROMOSOMES FROM ONCOPELTUS

1966 ◽  
Vol 31 (1) ◽  
pp. 31-42 ◽  
Author(s):  
Stephen L. Wolfe ◽  
Godfrey M. Hewitt
Keyword(s):  
Electron Microscope ◽  
Critical Point ◽  
Living Cells ◽  
Point Method ◽  
Oncopeltus Fasciatus ◽  
Langmuir Trough ◽  
Ringer’S Solution ◽  
Meiotic Chromosomes ◽  
Parallel Folding

Meiotic chromosomes were isolated from male Oncopeltus fasciatus by dissecting the testes under insect Ringer's solution and spreading the living cells on the Langmuir trough. After being dried by the critical point method, preparations were examined under the electron microscope. Chromosomes at all stages of prophase prove to be multistranded. A significant increase in the number of parallel 250 A fibers in the chromosomes occurs between zygotene and diakinesis. Parallel folding, rather than true multistrandedness, is interpreted as the mechanism responsible for this observed increase in multistrandedness. It has not been possible to determine whether the multistrandedness observed at leptotene represents true multistrandedness or is the result of parallel folding. Apparent multistrandedness is lost at metaphase when the 250 A fibers of the chromosomes become coiled more tightly. In preparations isolated by these methods, no structures other than the 250 A chromosome fibers are visible in the chromomeres, which appear as regionally coiled or folded areas of the fibers along the arm of the chromosome.

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