Bacteriological Testing of Compressed Air Supplies

Abstract

Nutrient agar (pH 7·4) was, in general, used for the tests, as wort agar (pH 4·85) allowed excessive growth of yeasts and moulds which suppressed bacterial development. Open exposure of plates to compressed air causes entrainment of organisms from the atmosphere, giving falsely high results. With appropriate shielding of the plates, however, this difficulty can be avoided, though care must be exercised in the choice of shielding device, or low results may be obtained as a result of imperfect deposition; a modification of the Hollaender & Dalla Valle apparatus (Publ. Hlth. Rep., Wash., 1939, 54, 564) is preferred for comparative routine tests. If it is desired to use a filtration method, calcium alginate wool may be used as collecting medium, being thereafter dissolved in sodium hexametaphosphate solution as a preliminary to plating.

Water Soluble Polymers. 75. Responsive Microdomains in Labeled N-Octylamide-Substituted Poly(sodium maleate-alt-ethyl vinyl ether): Transient Fluorescence and Time-Resolved Fluorescence Anisotropy Studies

“…The Perrin−Weber equation (eq 2) was used to calculate the overall rotational correlation time, θ, and rotational diffusion coefficient, D , of the dansyl labels from the SSFA measurements 〈 r 〉 is the average steady-state anisotropy in the emission region of the peak wavelength (±35 nm) and is independent of the emission wavelength in these measurements, τ is the emission lifetime, and r 0 represents the limiting value of 〈 r 〉 in a medium where no rotational diffusion occurs and Brownian motion is frozen.…”

“…The Perrin-Weber equation 19 (eq 2) was used to calculate the overall rotational correlation time, θ, and rotational diffusion coefficient, D, of the dansyl labels from the SSFA measurements.…”