SENSITIZATION TO HEAT BY X-RAYS

Sensitization to Heat by X-rays

1. Paramecium caudatum is sensitized to heat by sublethal dosages of x-rays. Thus if paramecia are irradiated, then exposed to a sublethal dosage of heat they are killed, but if the same heat exposure precedes the same dosage of radiations, they are not. 2. Sensitivity to both heat and x-rays is much greater in paramecia from the log growth phase than in those from the stationary phase of a cul...

Sensitization of Purine-starved Bacteria to X-rays.

1 Although the bottleneck traveling salesman problem has not apparently been discussed before, the closely related bottleneck assignment problem has been discussed and solved by 0. Gross, "The bottleneck assignment problem," the RAND Corporation P-1630, March 6, 1959. 2 See Kruskal, J. B., "On the shortest spanning subtree of a graph and the travelling salesman problem," Proc. Amer. Math. Soc.,...

Sensitization of Clostridium perfringens spores to heat by gamma radiation.

Spores of Clostridium perfringens, type A, were given separate or sequential treatments of gamma radiation (0 to 0.7 Mrad) and/or high temperature (93 to 103 degrees C). Prior heating, sufficient to inactivate 40 to 99% of the viable spores, had no effect on the subsequent radiation inactivation rate. Prior irradiation had a sensitizing effect on subsequently heated spores. The degree of sensit...

Chemical Analysis by X-Rays

Local Resistance to Spontaneous Mouse Cancer Induced by X-rays

Autografts from spontaneous cancers of mice when replanted into areas previously exposed to an erythema dose of x-rays, failed to grow in the majority of instances (71.4 per cent), while similar grafts inoculated into untreated areas grew in a large proportion of the animals (83.6 per cent). Autografts of spontaneous cancer, established and growing in the skin, disappeared in 76 per cent of ani...