Life Sciences Commons^™

An Organic Reference Specimen: Polyacrylonitrile Film Deposited On Oxidizable Metals By Electro-Polymerization, C. Boiziau, G. Lécayon

Scanning Electron Microscopy

Surface investigations of organic materials require the provision of reference specimens for calibrating experimental equipment.

Because of their specific properties (purity, reproducibility, well-known molecular structure and orderly inter-molecular structure, electronic properties associating conductive and insulating behaviour, quality of the film-to-metal bound), polyacrylonitrile films obtained through electro-polymerization on oxidizable metal cathodes (Fe, Ni, Cu) may be used as a first type of reference sample.

Experimental results, obtained by various surface investigation techniques are presented, and their validity evaluated.

Simulation With Pharmacological Agents Of Radiation Damage To Small Intestinal Villi, M. Indran, F. C. Boyle, K. E. Carr

Scanning Electron Microscopy

Irradiation induces damage to intestinal villi, resulting in a progressive decline in villous height and changes in topography. Gamma and neutron radiation are reported to cause changes in the structure of smooth muscle and nerve twigs of the intestinal wall. It is possible, therefore, that villous collapse may be due partly to changes in the underlying stromal elements as a result of damage to nerve or muscle.

To test this hypothesis, mice were treated with the drug reserpine which is known to affect the neural control of intestinal smooth muscle function and the small intestine was examined for topographical and …

Application Of Chelex Standard Beads In Integrated Morphometrical And X-Ray Microanalysis, W. C. De Bruijn, M. I. Cleton-Soeteman

Scanning Electron Microscopy

Chelex ion exchange beads loaded with a known amount (18.3% weight percentage (w/w)) of platinum, have been co-embedded with a mouse peritoneal cell population. To establish the influence of the various deconvolution methods applied, upon the platinum concentration in cytoplasmic granules and erythrocytes these cross-sectioned beads are used as a standard. It is concluded that irrespective of the deconvolution method chosen 1) the Pt concentration inside the particles is identical when the particles and the co-embedded Chelex Pt standard, are analysed strictly under the same instrumental conditions 2) the Pt concentration outside the particle is zero, or virtually zero when …

The Size Distribution Of Bovine Casein Micelles: A Review, C. Holt

Food Structure

This review considers the average size and size distribution of bovine casein micelles as measured by electron microscopy, light scattering and controlled pore glass chromatography, and the origin and biological function of the size distribution.

Recent work by electron microscopy has given average sizes in reasonable agreement with measurements on the same milk sample by light scattering . It is suggested that natural variations in averaqe micelle size and overestimation of micelle radii by light scattering methods as well as deficiencies in electron microscopical methodology were responsible for past discrepancies.

Electron microscopy and controlled pore glass chromatography provide evidence that …

Comparison Of The Microstructure Of Firm And Stem-End Softened Cucumber Pickles Preserved By Brine Fermentation, W. M. Walter Jr., H. P. Fleming, R. N. Trigiano

Food Structure

Soft and firm stem end tissues of cucumbers fermented at a low concentration of sodium chloride were examined by a combination of light microscopy {LM), transmission electron microscopy { TEM), and scanning electron microscopy { SEM) . When compared to firm tissue, softened tissue cell walls were swollen and striated, and the middle lamellae were poorly stained by the uranyl acetate-1 ead citrate used in TEM . When the tissue was penetrated by a circu l ar punch {1.5 mm diameter), cells in soft tissue tore along the middle l arne ll ae rather than across cell walls, as did …