Measurement of liquid scintillation sources of (210)Pb obtained from (222)Rn decay.
Liquid scintillation samples were filled with (222)Rn and the activity was measured with good precision after reaching the secular equilibrium with the progeny (218)Po, (214)Pb, (214)Bi and (214)Po. After decay of most of (222)Rn activity, the samples contain (210)Pb and progeny. The activities of (210)Pb and progeny can be calculated as a function of time using the initial (222)Rn activity. The samples were measured in a TDCR counter and the experimentally determined counting efficiencies are in accordance with previously published results.
Scintillating and wavelength shifting effect investigation of 3-methylpiridinium salicylate and its application in LSC measurements.
Possible application of a novel ionic liquid 3-methylpiridinium salicylate (3-MPS) in Liquid Scintillation Counting measurements has been explored. Its addition to several radionuclides' aqueous solutions shown a significant influence on 210Pb Cherenkov spectra, 210Pb and 226Ra gross alpha/beta spectra, even on 3H spectra appearance. 3-MPS manifested both wavelength shifting and scintillating effect, indicating that 3-MPS or other ionic liquids of similar structure soon might be implemented into the common LSC practise as an alternative to the commercial LSC cocktails.
THE IRON-ACETOCARMINE METHOD OF FIXING AND STAINING CHROMOSOMES
A short description of this procedure was given in Vol. 55 of the American Naturalist, pp. 573â€”574. The method has now been used almost daily for five years, and certain improvements have suggested themselves. The solution can be prepared by mixing about equal volumes of glacial acetic acid and water. To this is added powdered carmine in excess. The liquid is then â€ ? just brought to boil, cooled, and decanted. To the red solution there are then added a few drops of a solution of ferric hydrate in 50 per cent. acetic acid, to act as a mordant. The amount of iron varies with different objects. Too much produces a precipitate in a short time. The more