An Improved Cryogen for Plunge Freezing

An improved cryogen for plunge freezing.

The use of an alkane mixture that remains liquid at 77 K to freeze specimens has advantages over the use of a pure alkane that is solid at 77 K. It was found that a mixture of methane and ethane did not give a cooling rate adequate to produce vitreous ice, but a mixture of propane and ethane did result in vitreous ice. Furthermore, the latter mixture produced less damage to specimens mounted on...

Gating Movement of Acetylcholine Receptor Caught by Plunge-Freezing

The nicotinic acetylcholine (ACh) receptor converts transiently to an open-channel form when activated by ACh released into the synaptic cleft. We describe here the conformational change underlying this event, determined by electron microscopy of ACh-sprayed and freeze-trapped postsynaptic membranes. ACh binding to the α subunits triggers a concerted rearrangement in the ligand-binding domain, ...

An improved container for cells preserved by freezing.

The use of storage at low temperature to preserve cells for long periods has already proved valuable in medicine and biology and further applications of this technique may be expected. Though both fast and slow cooling have their advocates (see Smith, 1954, for a full comparative review), the most commonly used method employs glycerol (Polge, Smith, and Parkes, 1949) or dimethyl sulphoxide (Lov...

An Improved Algorithm for Network Reliability Evaluation

Binary Decision Diagram (BDD) is a data structure proved to be compact in representation and efficient in manipulation of Boolean formulas. Using Binary decision diagram in network reliability analysis has already been investigated by some researchers. In this paper we show how an exact algorithm for network reliability can be improved and implemented efficiently by using CUDD - Colorado Univer...

Quick freezing of mouse embryos by direct plunge into liquid nitrogen vapor: effects of sugars.