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Results for “MICROSCOPY, PHASE”

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At least 19 recordsLinked to original sources
PubMedDate not supplied

[Registration by dynamic phase microscopy of characteristic frequencies of phase height fluctuations of the myelin nerve fiber at rest and under stimulation].

The method of dynamic phase microscopy was used to study the dynamics of changes in the structure of paranodal and nodal regions of a myelin nerve fiber of brown frog Rana temporaria at rest and under stimulation. Regular structural changes with frequencies of 5.3 and 10.8 Hz in the nodal region of the myelin nerve fiber were detected. A rhythmic excitation leads to additional changes in the structure of the nodal region with a new frequency of 5.6 Hz. It is likely that the regular changes in the nodal region of the myelin nerve induced by rhythmic excitation are due to slow changes in the axolemma (changes in the mode of lateral diffusion of membrane phospholipids), induced by developing trace changes in the membrane potential of the axolemma. The fact that these changes do not occur in the paranodal region of the fibre may indicate either the localization of regular structural changes in the axolemma or the difficulties that arise during the registration of the useful signal in the vicinity of myelin by this method.

Animals↗
PubMedDate not supplied

Enumeration of previously frozen platelets using the Coulter Counter, phase microscopy, and the technicon optical system.

The Coulter Counter, phase microscopy, and the Technicon optical system were used to enumerate platelets in samples of whole blood, platelet-rich plasma, platelet concentrates before and after addition of DMSO, and on platelet concentrates that had been frozen, thawed, and washed. We observed agreement among the three counting methods when platelet counts were determined in whole blood, platelet-rich plasma, and platelet concentrate before and after DMSO addition. Enumeration after the cryopreservation process, however, showed highly significant differences among the counting systems. Platelet counts on platelet concentrates after freezing the thawing performed with the Coulter Counter were 25 per cent greater than with phase microscopy and 55 per cent greater than with Technicon. Counts with phase microscopy were 30 per cent greater than Technicon values. These data indicate that the method used to enumerate previously frozen platelets affects the apparent platelet count.

Cryoprotective Agents↗
PubMedDate not supplied

[Cooperative processes in mitochondria: registration by dyanmic phase microscopy].

The spectra of phase fluctuations in mitochondria were measured by the method of dynamic phase microscopy. Contrasting components were revealed whose intensity markedly changed at distances of 100-300 nm. Similar frequency components were observed in the spectra of ATP-stimulated fluctuations in liposomes with the incorporated ATPase. The values of the frequency and intensity of contrasting components in spectra of liposomes, mitochondria, and cells are presented. The possibility of determining the position of active enzyme complexes from their characteristic frequencies is discussed.

Adenosine Triphosphatases↗
PubMed2003

Emulated super-resolution using quantitative phase microscopy.

In the case of coherent illumination, knowledge of the phase and the amplitude of a light wave constitutes complete information. Phase and amplitude information can now be simply acquired using the technique of quantitative phase microscopy. It has been shown that this information allows other imaging modalities to be emulated. In this paper we consider how this information may be used to perform a form of super-resolution by emulating the effect of an annular pupil.

Image Processing, Computer-Assisted↗
PubMed1963

ULTRAVIOLET AND PHASE MICROSCOPY OF SPORULATING SACCHAROMYCES.

Miller, Glendon R. (Southern Illinois University, Carbondale), Dan O. McClary, and Wilbert D. Bowers, Jr. Ultraviolet and phase microscopy of sporulating Saccharomyces. J. Bacteriol. 85:725-731. 1963.-During active growth, the cytoplasm of yeast cells is densely absorbent to ultraviolet light at 260 mmu, whereas the nucleus is only faintly so, and the vacuole is nonabsorbent. After 24 hr on presporulation medium (about the age of transfer to acetate sporulation medium), the cells manifest many characteristics of starvation. The cytoplasm is weakly absorbent to ultraviolet light except for a dense zone immediately surrounding the vacuole and one or two groups of highly refractile granules clustered on one or both sides of the juncture of the nucleus and the vacuole. After several hours on the acetate sporulation medium, the cells undergo a progressive vacuolation until four or more large vacuoles appear, separated by granular cytoplasm. The nucleus is obscured to ultraviolet light during the vacuolation stage, at which time previous studies have shown its division to occur, and remains so during the rest of the cycle. Photographs of densely granulated cells, at various wavelengths of ultraviolet and visible light, indicated several different types of granules with respect to their absorption spectra. With continued development of the ascus, the granules increase in number until they fill the entire cell and obscure the vacuoles, after which they condense into a compact mass, leaving much of the cell empty. Spores emerge from the granular mass as separate, ultraviolet-absorbent regions without distinguishable cell walls, which seem to be the last structures formed. The rudimentary spores contain a central cluster of dense granules and are separated within the ascus by optically dense, granular partitions which diminish as spore walls are laid down. With the maturing of the ascus, the granules and epiplasm disappear, and the ascus wall is drawn tightly around the more or less homogeneously absorbent spores.

Cell Nucleus↗
PubMed1995

Recent developments in electron holography for phase microscopy.

This paper reports on the recent remarkable progress made in electron phase microscopy, especially due to the development of both a "coherent" field-emission electron beam and the related image processing techniques. With these techniques, the phase distribution of an electron beam transmitted through a specimen can now be measured with a precision of within 1/100 of the electron wavelength to observe the thickness distribution of a uniform specimen at the atomic level, the magnetic domain structures in a ferromagnetic thin film, and individual vortices in a superconducting thin film. Vortices in superconducting thin films have become dynamically observable by Lorentz microscopy.

Holography↗