Solvent effects on the effective interactions among colloidal particles: a simple molecular model

The vital role played by the lymphatic capillaries in the transfer of tissue fluids and particulate materials from the connective tissue area can be demonstrated by the rapid removal of injected vital dyes into the tissue areas. In order to ascertain the mechanisms involved in the transfer of substances from the connective tissue area at the ultrastructural level, we have injected colloidal particles of varying sizes which range from 80 A up to 900-mμ. These colloidal particles (colloidal ferritin 80-100A, thorium dioxide 100-200 A, biological carbon 200-300 and latex spheres 900-mμ) are injected directly into the interstitial spaces of the connective tissue with glass micro-needles mounted in a modified Chambers micromanipulator. The progress of the particles from the interstitial space into the lymphatic capillary lumen is followed by observing tissues from animals (skin of the guinea pig ear) that were injected at various time intervals ranging from 5 minutes up to 6 months.

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Toward an alignment of the actin molecule within the actin filament

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100075981 ◽

1983 ◽

Vol 41 ◽

pp. 450-451

Author(s):

P.R. Smith ◽

W.E. Fowler ◽

U. Aebi

Keyword(s):

Actin Filament ◽

Diffraction Data ◽

Quantitative Estimate ◽

Molecular Model ◽

Quantitative Comparison ◽

Regulatory Proteins ◽

Essential Information ◽

X Ray ◽

Maximum Resolution ◽

Lack Of Information

An understanding of the specific interactions of actin with regulatory proteins has been limited by the lack of information about the structure of the actin filament. Molecular actin has been studied in actin-DNase I complexes by single crystal X-ray analysis, to a resolution of about 0.6nm, and in the electron microscope where two dimensional actin sheets have been reconstructed to a maximum resolution of 1.5nm. While these studies have shown something of the structure of individual actin molecules, essential information about the orientation of actin in the filament is still unavailable.The work of Egelman & DeRosier has, however, suggested a method which could be used to provide an initial quantitative estimate of the orientation of actin within the filament. This method involves the quantitative comparison of computed diffraction data from single actin filaments with diffraction data derived from synthetic filaments constructed using the molecular model of actin as a building block. Their preliminary work was conducted using a model consisting of two juxtaposed spheres of equal size.

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Deposited emulsion particles in the pores of aluminum oxide film

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100109392 ◽

1978 ◽

Vol 36 (1) ◽

pp. 450-451

Author(s):

Michio Ashida ◽

Yasukiyo Ueda

Keyword(s):

Oxide Film ◽

Acid Solution ◽

Barrier Layer ◽

Colloidal Particles ◽

Oxalic Acid Solution ◽

Anodic Oxide ◽

Anodic Oxide Film ◽

Carbon Replica ◽

Sectioning Method ◽

Thin Sectioning

An anodic oxide film is formed on aluminum in an acidic elecrolyte during anodizing. The structure of the oxide film was observed directly by carbon replica method(l) and ultra-thin sectioning method(2). The oxide film consists of barrier layer and porous layer constructed with fine hexagonal cellular structure. The diameter of micro pores and the thickness of barrier layer depend on the applying voltage and electrolyte. Because the dimension of the pore corresponds to that of colloidal particles, many metals deposit in the pores. When the oxide film is treated as anode in emulsion of polyelectrolyte, the emulsion particles migrate onto the film and deposit on it. We investigated the behavior of the emulsion particles during electrodeposition.Aluminum foils (99.3%) were anodized in either 0.25M oxalic acid solution at 30°C or 3M sulfuric acid solution at 20°C. After washing with distilled water, the oxide films used as anode were coated with emulsion particles by applying voltage of 200V and then they were cured at 190°C for 30 minutes.

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