title: Progression of fusion during rapid freezing for electron microscopy.
abstract: The method used to determine the rate of fusion was based on the large difference in the dielectric constants of water and ice. A thin (50--60 micrometers) slice of a gelatin gel was used as the dielectric in a plate condenser. The slice was placed on a metal electrode built in a specimen carrier which was dropped on a silver freezing surface kept at below 70 K, forming the other plate of the condenser. Freezing of the gelatin causes a marked decrease in a 20,000 cycle current passing through the condenser. Since the thickness of the layer of frozen material was shown to be a function of the reciprocal of the current, it was possible to determine the course of fusion of the section. Freezing started at a high rate which declined during the first 5 ms but then increased again and usually became quite high at the end of fusion.
mesh_terms: D000818:Animals; D002356:Cartilage; D002540:Cerebral Cortex; D004553:Electric Conductivity; D005615:Freezing; D005780:Gelatin; D006652:Histological Techniques; D007700:Kinetics; D008433:Mathematics; D008854:Microscopy, Electron
chemical_list: D005780:Gelatin