A Permeability Test with Radioactive Indicators

Permeability of Erythrocytes to Radioactive Potassium

The diffusion coefficients for the exchange of potassium across the membrane of erythrocytes of humans, rats, and rabbits have been determined by the use of artificially radioactive potassium, both into and out of the erythrocytes both in vitro and in vivo. The diffusion coefficients found in minutes(-1) were 0.2 to 0.25 x 10(-3) for human, 0.32 to 0.665 x 10(-3) for rabbits, and 1.0 x 10(-3) f...

Giant radioactive halos: indicators of unknown radioactivity?

A new group of giant radioactive halos has been found with radii in excess of anything previously discovered. Since alternate explanations for these giant halos are inconclusive at present, the possibility is considered that they originate with unknown alpha radioactivity, either from isomers of known elements or from superheavy elements.

A Virtual Rapid Chloride Permeability Test

The rapid chloride permeability test (RCPT), as it is commonly called, has been in existence for over 20 years and was standardized by ASTM over 15 years ago. The test is used extensively in the concrete industry for assessing concrete quality and is now being included in concrete specification documents. Because the underlying physics of the test are fairly well understood, it is possible to c...

The permeability of the hamster placenta to radioactive cadmium.

A tetrad test for causal indicators.

The authors propose a confirmatory tetrad analysis test to distinguish causal from effect indicators in structural equation models. The test uses "nested" vanishing tetrads that are often implied when comparing causal and effect indicator models. The authors present typical models that researchers can use to determine the vanishing tetrads for 4 or more variables. They also provide the vanishin...