Cyclotron production and radiochemical purification of (88,89)Zr via α-particle induced reactions on natural strontium.

The radionuclides (88)Zr and (89)Zr have been produced by cyclotron irradiation of (nat)SrO with 35 MeV α-particles at a beam current of 15 µA. The thick source production yield of (89)Zr is ~3.1 MBq µA(-1) h(-1). A two-step radiochemical purification utilising anion-exchange chromatography in hydrochloric and hydrofluoric acids has been developed to separate (88,89)Zr from the target material, natural strontium, the target substrate, aluminium, and long-lived (88)Y.

Chemical and mineralogical composition of the Mongolian rural soils and their uranium sorption behavior.

Distribution of uranium (VI) between soil solids and solutions is a key parameter in assessing the risk to the biosphere of disposing uranium-rich waste products from nuclear plants as well as uranium (U) ore mining. Both of these topics have recently been brought to public attention in Mongolia. Regional background levels of soil elements are an important dataset for accessing the actual environmental situation and monitoring pollution levels. Little information, however, is available on background concentrations of various elements in Mongolian soils. Thirteen rural soils were sampled from six provinces in Mongolia, and the concentrations of macro-, micro- and trace elements were measured. The values obtained served as a reference (baseline) for uncontaminated soils. The soils were characterized with slightly acidic to strongly alkaline pH values. With the exception of the sample from a western province, all the soils investigated contained little organic matter. The content of soil elements did not vary widely among geographical regions. The concentration of most micro elements was within the range of worldwide soil values but the value for Zn tended to be moderately higher. The U (VI) sorption into the soils was investigated using the batch technique and the (237)U radionuclide tracer, produced by the photo fission reaction (238)U(γ, n) (237)U at an electron accelerator. The (237)U distribution coefficient (K(d)), derived from the sorption isotherms, was related to solution pH and varying from 9 to 2547 mL g(-1) when the pH ranged between 3 and 7.7. The sorption process was interpreted in terms of the formation of different U (VI) species at given concentrations, calculated using the Speciation program with and without carbonate in the system. The U sorption isotherm displayed two general patterns: one where sorption decreased as solution pH increased, showing a maximum at pH 3, and another pattern revealed an adsorption maximum at pH 5 and then decreased up to pH 7.7 (the final solution pH). The observed decrease in K(d) when solution pH increased from 6 to 8 was consistent with the increased formation of soluble UO(2)(OH)(2) species. A linear negative correlation between lgK(d) and the solution pH was observed similarly to that reported for the soils with a pH ≥ 6.

Production of (117m)Sn with high specific activity by cyclotron.

A method to produce (117m)Sn radionuclide using accelerator production route is described. A new method is proposed to separate the (117m)Sn. Specific activities and thick target yield for (116)Cd(α,3n)(117m)Sn reaction at E(α)=35MeV bombarding energy were determined. The estimated production yield of (117m)Sn was 37.5kBq/µAh for 13.16 mg/cm(2) natural cadmium-oxide target and 410 kBq/µAh for 11.07 mg/cm(2) highly enriched (95%) (116)CdO target. The method developed for separation of (117m)Sn from Cd using anion-exchange resin (Dowex -1×8, fluorine form, 400 mesh) can achieve 98% radiochemical yield of (117m)Sn with more than 99% radionuclidic purity. The estimated specific activity is 2.4 GBq/mg that can be reached with the used irradiation conditions.

[Evaluation of the consequences of stress factors on plant seeds growing in a 30-km zone of Balakovo AES]. / Otsenka posledstvii vliianiia stressovykh faktorov na semena rastenii, proizrastaiushchikh v 30-kilometrovoi zone Balakovskoi AES.

The effect of stress factors (small doses of radiation and maximum temperatures in the econiche of the tested plants (tmax)) as well as aging on pea seeds, both acting independently and in combination, is estimated. Here we evaluate the influence of oxidizing stress on pea seeds in the laboratory (gamma-irradiated with 7 cGy at 0.3-19.1 cGy/h, tmax approximately 30-32 degrees C) and on natural plantain seeds collected in a 30-km zone of NPP (radiation exposure approximately 15 R/h, tmax approximately 38-40 degrees C). We have mathematically modeled CAs frequencies in root seedlings meristeme by invoking an enhancing factor transmitted from cell to cell. It is shown under the stress conditions: 1) CA frequency decreases whereas the fraction of inviable seeds (IS) increases, the dependence of IS on CA frequency being inversed; 2) a stimulation of proliferation of cell was observed; 3) a bystander effect appears; 4) antioxidative status (AOS) of seeds influences on adaptation on the all levels of the organization; 5) IS increases up to 73-80% under the combined effect of radiation and heat stresses.

Study of the 111In-DTPA complex by the electromigration method.

The electrophoretic behavior of the 111In-DTPA radiopharmaceutical has been investigated. The stability constant, diffusion coefficient and effective charge of the complex as well as the temperature dependence of the electrophoretic mobility were determined. No-carrier-added 111In with high specific activity was used in the electrophoretic experiments in ultramicroconcentrations (10(-9)M).

[The antioxidant status of the seeds in populations of the great plantain (Plantago major L.) growing in an area exposed to the Balakovo Atomic Electric Power Station and to chemical enterprises]. / Antioksidantnyi status semian populiatsii rastenii podorozhnika bol'shogo (Plantago major L.), proizrastaiushchikh v raione deistviia Balakovskoi AES i khimicheskikh predpriiatii.

The results of the determination of radionuclide and chemical (multielement analysis) soil pollution are presented. The data on antioxidant status of plantain (Plantago major L.) in conjunction with the data on radionuclide and chemical pollution are analyzed. The most significant decrease in antioxidant activity of plant seeds was observed in areas situated along the most frequent wind direction in the region in summer 1998. It is suggested that lower antioxidant status is caused by the chronic radionuclide release on the chemically polluted territories.

[Difference in the content of trace elements in muscles]. / Razlichiia myshts po mikroelementnomu sostavu.

By using X-ray fluorescence analysis we have performed a comparative study of the trace elements content of phasic and tonic muscles of scallops. The phasic (yellow) muscles were found to be richer in Fe and Cu and more deficient in Zn, Br, and Sr, as compared with the tonic (white) muscles. No appreciable difference in the Rb content was revealed. An analysis of the results obtained allows one to outline a classification of Fe, Cu, Zn, Br and Sr according to their properties which are connected with various homeostatic requirements of the muscles with regard to the trace elements.