Environmental tritium of the Danube basin in Yugoslavia.

An overview of environmental distribution of tritium in the Danube basin in Yugoslavia during the period 1976-1990 is presented. Temporal and regional variations of environmental tritium in the Danube along its flow (1425-847 km from the confluence) and its tributaries (the Sava, the Tisa, the Velika Morava and the Timok) at various locations, as well as in alluvial groundwaters, are given. In Belgrade, monthly values of tritium in rainfall ranged from 1.

The Gamma Contamination Food Factor.

We suggest that radioactive food contamination, as determined solely by a quantitative gamma-ray spectroscopic measurement, may, apart from the total activity per unit mass, be for quick reference conveniently characterized by another single figure which we call the "Gamma Contamination Food Factor" (GCFF). This factor may be defined as the ratio of the total specific activity of gamma-ray-emitting radionuclides in the food sample (except that of 40K) to the specific activity of 40K either in the sample itself or in an "average man". We discuss briefly the meaning and advantages of these definitions.

The DNA guanyl radical: kinetics and mechanisms of generation and repair.

The one-electron oxidation of DNA bases and single-stranded DNA was studied by pulse radiolysis of aqueous solutions from pH 7-7.4 at 20 degrees C. Thallic ions, Tl(II), were found to rapidly oxidize the purine nucleotides, deoxyguanosine 5'-monophosphate, k[Tl(II) + dGMP2-] = 3.

Synthesis of p-aminohippuric acid analog and its labeling by technetium-99m.

A procedure is described for the synthesis of p-[(bisacarboxymethyl)aminomethyl carbamino] hippuric acid (PAHIDA). The compound was identified by i.r.

Investigation of the system: tri-n-butyl phosphate-n-tetradecane by gas-liquid chromatography.

The interaction of tri-n-butyl phosphate (TBP) with various solutes has been investigated by gas-liquid chromatography (GLC). In the case of benzene and chloroalkane solutes, the formation of 1:1 complexes has been assumed. The nonlinear behaviour of partition coefficients of the solutes with high TBP concentration in an inert solvent (n-tetradecane) has been explained in terms of the dimerization of TBP.

Absolute calorimeter for measuring low-energy outputs from CO2 lasers.

This paper describes the construction of a calibrated energy measuring device for pulsed CO(2) lasers of low output energy. An aluminium disk of low thermal capacity has been used for the detection of laser radiation. An Al(2)O(3) layer has been electrolytically deposited on the aluminium disks.

Ortho-effects of carboxyl, sulpho and arsono groups on the protonation and dissociation constants of mono-azo and bis-azo chromotropic acid derivatives.

The effect of carboxyl sulpho and arsono groups on the protonation and dissociation constants of mono-azo and bis-azo chromotropic acid derivatives has been investigated. From the value obtained for the effect of the substituents the equation; ortho-effect = log K(ortho)-log K para has been derived. The causes of the effect are discussed.

Spectrochemical determination of impurities in telluric acid.

An emission spectrographic method is described for determination of 20 elements present as impurities in telluric acid. Samples are excited in a 12-A. d.

Spectrophotometric determination of dimethyl sulphoxide.

A spectrophotometric method for the determination of milligram quantities of dimethyl sulphoxide in aqueous solutions has been developed. The method is based on the medium effect on the visible absorption spectra of metal salt solutions. Out of several compounds investigated, iron(III) alum was chosen as most suitable for this purpose.

New possibilities for routine use of oxalic acid solutions in in-pile dosimetry.

New data are given on the use of oxalic acid, in light and heavy water solutions, for in-pile chemical dosimetry. The method of calculating the absorbed doses in low-Z materials is described. Results of chemical measurements in the core of the heavy-water-moderated reactor at Vinca (Yugoslavia) are compared with the results of calorimetric measurements conducted under identical conditions.