A vapor arc light source has been adapted to the study of the lethal action on bacteria of near-ultraviolet (UV) and visible light. Its use makes possible much shorter exposure times than could be obtained from previously available sources. The output of radiant energy is sufficient to provide a fairly detailed action spectrum for lethality in the long-UV and visible region without the addition of exogenous sensitizers. Populations of cells of
Escherichia coli
WP2 were inactivated through five log
10
cycles with light at 460 nm. Significant inactivation also was obtained with light at 550 and 650 nm.
A vapor arc light source has been adapted to the study of the lethal action on bacteria of near-ultraviolet (UV) and visible light. Its use makes possible much shorter exposure times than could be obtained from previously available sources. The output of radiant energy is sufficient to provide a fairly detailed action spectrum for lethality in the long-UV and visible region without the addition of exogenous sensitizers. Populations of cells of Escherichia coli WP2 were inactivated through five log10 cycles with light at 460 nm. Significant inactivation also was obtained with light at 550 and 650 nm.
A dual channel temperature recorder is described which can measure temperatures linearly over a range of 0 to 80 C. The sensitivity can be adjusted so that any temperature span, as small as 30, will cover recorder full scale, and temperatures can be read to 0.10. The recorder provides two independent, permanent records of temperature variations which can be related directly to the time of day.
A dual channel temperature recorder is described which can measure temperatures linearly over a range of 0 to 80 C. The sensitivity can be adjusted so that any temperature span, as small as 3�, will cover recorder full scale, and temperatures can be read to 0.1�. The recorder provides two independent, permanent records of temperature variations which can be related directly to the time of day.
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