Residual radionuclide concentrations and estimated radiation doses at the former French nuclear weapons test sites in Algeria.

In order to assess the level of residual radioactivity and evaluate the radiological conditions at the former French nuclear testing sites of Reggane and Taourirt Tan Afella in the south of Algeria, the International Atomic Energy Agency, at the request of the government of Algeria, conducted a field mission to the sites in 1999. At these locations, France conducted a number of nuclear tests in the early 1960s. At the ground zero locality of the ''Gerboise Blanche'' atmospheric test (Reggane) and in the vicinity of a tunnel where radioactive lava was ejected during a poorly contained explosion (Taourirt Tan Afella), non-negligible levels of radioactive material could still be measured. Using the information collected and using realistic potential exposure scenarios, radiation doses to potential occupants and visitors to the sites were estimated.

The new IAEA-372 grass-certified reference material for (40)K and (137)Cs.

A new grass-certified reference material characterized for (137)Cs and (40)K has been issued by the International Atomic Energy Agency. Characterization of this material was conducted by a group of national metrological institutes and expert laboratories. The paper describes the process for assigning the certified reference value to the material.

Functional properties of honey supplemented with bee bread and propolis.

The aim of this work was characterisation of functional properties of honey enriched with propolis and beebread. In first step of experiment, soft propolis extract (SPEx) was obtained by extraction of propolis with ethanol. SPEx (0.25 to 1.0% w/w) as well as beebread (5 to 15% w/w) were implemented into natural honey. Fortified honeys were investigated in terms of total phenolic content, radical scavenging activity and ferric reducing antioxidant power, also their effects on the micro-organisms growth was examined. It was found that beebread had the most significant influence on antioxidant properties. On the other hand, all tested honeys showed antibacterial activity against Escherichia coli but not against Micrococcus luteus. Honeys with 1% of propolis addition were the most effective in this case. Research has indicated that for antioxidant and antimicrobial properties of honey, it is beneficial to enrich it in both beebread and propolis.

Platelet-activating factor receptor-antagonist (BN 52021) stabilizes the oxidative-antioxidative balance and attenuates the morphological changes in the gastrointestinal tract in experimental hemorrhagic shock.

The influence of the platelet-activating factor receptor-antagonist (BN 52021) and polyelectrolyte solution (PES) on the morphology and oxidant-antioxidant equilibrium in the gastrointestinal wall in hemorrhagic shock was examined in rats. The animals were divided into five groups: I - control, II - sham operation, III - untreated hemorrhagic shock lasting 75 minutes, IV - shock treated with PES, and V - shock treated with BN 52021 and PES. The most expressed morphological changes were found in the small intestine in group IV (shock treated with PES) and in group III (untreated shock). Morphological changes were well correlated with the malondialdehyde (MDA) level reflecting oxidative tissue injury and with the antioxidative potential: sulfhydryl compounds (-SH) level, and superoxide dismutase (SOD) activity. The signs of morphological and biochemical injury to the gastrointestinal tract in animals from group V (treated with BN 52021 and PES) were significantly less expressed than those in groups III and IV. The results suggest an essential role of PAF in oxygen radicals-mediated gastrointestinal injury and a beneficial effect of the early application of BN 52021 in hemorrhagic shock.

Enhanced sensitivity for the determination of selenium by INAA.

A working analytical procedure for selenium determinations by INAA, using gamma spectrometry with a germanium well-type detector, is presented. The spectral line at 400.7 keV is employed, enhanced with the effect of energy summing in true coincidence of cascade photons. The main advantage of the method is high efficiency and reliable, interference-free results; potential drawbacks are increases in input count rate and pile-up losses, decrease in resolution, and sensitivity to errors in sample-to-detector geometry. The procedure is applied to certification analysis of reference materials, large-area biomonitoring by oak leave samples, and determination of separated proteins.

Detection and determination of selenoproteins by nuclear techniques.

Microbeam X-ray spectrometry, energy-dispersive X-ray fluorescence analysis, and neutron activation analysis were evaluated for the detection of selenium contained in the selenoprotein glutathione peroxidase. The glutathione peroxidase had been previously separated using polyacrylamide gel electrophoresis. The use of Bragg-reflected polarized X-ray beams was employed in the X-ray fluorescence measurements to minimize the problem of scatter owing to the gel matrix. Current detection limits of selenium in a gel matrix are 2.1 ng in the bench-top microbeam X-ray system and 30-60 ng using XRF with polarized beams. Neutron activation analysis was used for quality-control measurements, with a detection limit here of < 0.08 ng. The work has in principle established the feasibility of such an approach.

Isotopic composition and origin of uranium and plutonium in selected soil samples collected in Kosovo.

Soil samples collected from locations in Kosovo where depleted uranium (DU) ammunition was expended during the 1999 Balkan conflict were analysed for uranium and plutonium isotopes content (234U, 235U, 236U, 238U, 238Pu, (239 + 240)Pu). The analyses were conducted using gamma spectrometry (235U, 238U), alpha spectrometry (238Pu, (239 + 240)Pu), inductively coupled plasma-mass spectrometry (ICP-MS) (234U, 235U, 236U, 238U) and accelerator mass spectrometry (AMS) (236U)). The results indicated that whenever the U concentration exceeded the normal environmental values (approximately 2 to 3 mg/kg) the increase was due to DU contamination. 236U was also present in the released DU at a constant ratio of 236U (mg/kg)/238U (mg/kg) = 2.6 x 10(-5), indicating that the DU used in the ammunition was from a batch that had been irradiated and then reprocessed. The plutonium concentration in the soil (undisturbed) was about 1 Bq/kg and, on the basis of the measured 238Pu/(239 + 240)Pu, could be entirely attributed to the fallout of the nuclear weapon tests of the 1960s (no appreciable contribution from DU).

Ethanol ingestion decreases superoxide dismutase activity and diminishes -SH compounds in the liver and red blood cells in rats.

SOD activity and -SH compounds in the liver and RBCs, and some hematological parameters were investigated in control rats and in those submitted to chronic (3 months) intoxication with ethanol. We found significantly lower SOD activity and a decrease in -SH groups in the liver and RBCs of ethanol-treated rats in comparison with the control group. The hemoglobin content and mean corpuscular hemoglobin concentration were reduced, while mean corpuscular volume of RBCs was increased when compared with the control group.

Oxygen-derived free radicals in kidney in experimental hemorrhagic shock treated by PAF-receptor antagonist BN 52021.

Renal damage in rat hemorrhagic shock model was assessed by estimation of the reactive oxygen metabolites generation (malondialdehyde measured as thiobarbituric acid reactive substances) and antioxidative potential (activity of Cu-, Zn- superoxide dismutase, activity of glutathione reductase and level of sulfhydryl compounds). It was found that treatment with BN 52021 (a platelet-activating factor antagonist), and polyelektrolyte solution had had a beneficial effect in comparison with both the untreated shock and shock treated by reperfusion only.

Preparation and characterization of a set of IAEA reference air filters for quality control in air-pollution studies.

Several sets of reference air filters were prepared as part of an IAEA evaluation of the performance of laboratories involved in air-pollution studies. Each set comprised three polycarbonate membrane filters, two of which were loaded with urban air particulate matter (APM) obtained in Vienna or Prague, and one unloaded filter. The filters were loaded by filtration of a suspension of the APM materials in water. The homogeneity both of bulk APM materials and of the loaded filters was evaluated and found suitable by determining several elements by instrumental neutron-activation analysis (INAA), proton-induced X-ray emission (PIXE), and micro-X-ray energy-dispersive fluorescence analysis (micro-EDXRF). After evaluation of the homogeneity, INAA, PIXE, EDXRF, atomic absorption spectrometry (AAS), inductively coupled plasma optical emission spectrometry (ICP-OES), and ICP mass spectrometry (ICP-MS) were used to characterize the filter materials and establish "target values" and their associated standard deviations for 15 elements. Problems encountered during the preparation of these unique, simulated air filters and the criteria for setting both the target values and standard deviations are presented.