No abstract available

[en] Activity distribution is plotted in a curve scan for precise differentiation of scintigrams. This permits a comparative presentation of the accumulating areas of both kidneys. A decrease of these areas results in an alteration of the quotient. In case of kidney insufficiency, the liver activity may be determined in comparison to the kidney activity. The analysis of the curve scan indicates different processes, thus facilitating the interpretation. (author)

[en] A positive parity band based on an isomeric 13/2⁺ level exists in all of the odd mass Hg isotopes at mass A~190, and it has been described as a (vi^-1_3/2) decoupling band, which, in the most recent studies, is increased to 49/2+ for ¹⁹⁷Hg. Another ∆I=2 sequence of negative parity band is also observed with a 21/2/^- bandhead and extended up to 45/2^- in ¹⁹⁷Hg, which are described as members of semi decoupled band. The levels of the 13/2⁺ band have a similar feature with their even core isotopes. In this report we will be discussing about the polarization measurements of ¹⁹⁷Hg which was computed and compared between experimental and theoretical results

[en] Here, the structure of decoupled positive-parity and semidecoupled negative-parity bands up to high spin in ^197,199Hg has been studied using multinucleon transfer reactions with the Gammasphere array. A positive-parity band in ¹⁹⁹Hg with the (vi_13/2)³ decoupled configuration that deexcites to levels in the negative-parity sequences is newly established. The semidecoupled sequences in both isotopes are extended to higher spin. Rotation-aligned angular momenta and crossing frequencies determined from experiment are in fair agreement with those from cranking calculations. Finally, a transition from oblate collective rotation at low spin to triaxial noncollective shapes at high spin is indicated.

[en] In lake food webs, pelagic basal organisms such as bacteria and phytoplankton incorporate mercury (Hg"2"+) from the dissolved phase and pass the adsorbed and internalized Hg to higher trophic levels. This experimental investigation addresses the incorporation of dissolved Hg"2"+ by four plankton fractions (picoplankton: 0.2–2.7 μm; pico + nanoplankton: 0.2–20 μm; microplankton: 20–50 μm; and mesoplankton: 50–200 μm) obtained from four Andean Patagonian lakes, using the radioisotope "1"9"7Hg"2"+. Species composition and abundance were determined in each plankton fraction. In addition, morphometric parameters such as surface and biovolume were calculated using standard geometric models. The incorporation of Hg"2"+ in each plankton fraction was analyzed through three concentration factors: BCF (bioconcentration factor) as a function of cell or individual abundance, SCF (surface concentration factor) and VCF (volume concentration factor) as functions of individual exposed surface and biovolume, respectively. Overall, this investigation showed that through adsorption and internalization, pico + nanoplankton play a central role leading the incorporation of Hg"2"+ in pelagic food webs of Andean lakes. Larger planktonic organisms included in the micro- and mesoplankton fractions incorporate Hg"2"+ by surface adsorption, although at a lesser extent. Mixotrophic bacterivorous organisms dominate the different plankton fractions of the lakes connecting trophic levels through microbial loops (e.g., bacteria–nanoflagellates–crustaceans; bacteria–ciliates–crustaceans; endosymbiotic algae–ciliates). These bacterivorous organisms, which incorporate Hg from the dissolved phase and through their prey, appear to explain the high incorporation of Hg"2"+ observed in all the plankton fractions. - Highlights: • Hg"2"+ incorporation in lake plankton fractions was studied using the isotope "1"9"7Hg"2"+. • Hg"2"+ incorporation was assessed using three different bioconcentration factors. • Bioconcentration factors related with fraction cell abundance, surface and biovolume. • Picoplankton and nanoplankton lead the incorporation of Hg"2"+ in pelagic food webs. • Mixotrophic species appear to enhance Hg incorporation via bacteria feeding

[en] Experiments to determine the mercury methylation potential were performed on sediments from two locations on the river Idrijca (Slovenia), differing in ambient mercury concentrations. The tracer used was the radioactive isotope ¹⁹⁷Hg. The benefit of using this tracer is its high specific activity, which enables spikes as low as 0.02 ng Hg²⁺ g^-1 of sample to be used. It was therefore possible to compare the efficiency of the methylation potential experiments over a range of spike concentrations from picogram to microgram levels. The first part of the work aimed to validate the experimental blanks and the second part consisted of several series of incubation experiments on two different river sediments using a range of tracer additions. The results showed high variability in the obtained methylation potentials. Increasing Hg²⁺ additions gave a decrease in the percentage of the tracer methylated during incubation; in absolute terms, the spikes that spanned four orders of magnitude (0.019-190 pg g^-1 of sediment slurry) resulted in MeHg formation between 0.01 and 0.1 ng MeHg g^-1 in Podroteja and Kozarska Grapa. Higher spikes resulted in slightly elevated MeHg production (up to a maximum of 0.27 ng g^-1). The values of methylation potential were similar in both sediments. The results imply that the experimental determination of mercury methylation potential strongly depends on the experimental setup itself and the amount of tracer added to the system under study. It is therefore recommended to use different concentrations of tracer and perform the experiments in several replicates. The amount of mercury available for methylation in nature is usually very small. Therefore, adding very low amounts of tracer in the methylation potential studies probably gives results that have a higher environmental relevance. It is also suggested to express the results obtained in absolute amounts of MeHg produced and not just as the percentage of the added tracer. (orig.)

[en] A ^natAu foil was irradiated with 23 MeV protons to produce no-carrier-added (NCA) ^{195(m,g),197m}Hg in the target matrix. The NCA Hg radioisotopes were separated from the natural Au target by liquid-liquid extraction (LLX) employing RTIL 1-butyl-3-methylimidazolium hexafluorophosphate (C₄mim)(PF₆) as extractant. The optimum separation condition was achieved at 10^-4 M HNO₃ and with 0.2 mL (C₄mim)(PF₆) after 10 min shaking and settling time, where 100% of the bulk Au was extracted to the IL phase leaving >99% NCA Hg in the aqueous phase. The IL was recovered by washing with 1 M K₂S₂O₅ and also with freshly prepared 1 M FeSO₄ and was reused. (author)

No abstract available

[en] Published in summary form only

[en] All the odd mass Hg isotopes around mass A~190 have a positive parity band built on an isomeric 13/2⁺ level, and been interpreted as a (vi^-1_13/2) decoupled band. This band is extended up to 49/2⁺ for ¹⁹⁷Hg in the latest work. Another ΔI=2 sequence of negative parity band is also observed with a 21/2^- bandhead and extended up to 45/2^- in ¹⁹⁷Hg, which are described as members of a semi decoupled band. The vi^-1_13/2 configuration of the decoupled band built on the isomeric 13/2⁺ level configuration of the semi-decoupled band built on the 21/2^- level are confirmed from our work also. Linear nature of the Energy vs I(I+1) plot confirms the rotational nature of the newly observed semi-decoupled band built on the 29/2^- (2364 keV) level. Its configuration is supposed to be of three quasi-particle in nature, with one neutron from the p_3/2 or f_5/2 and two i_13/2 neutrons. A known 530 keV and a newly observed 202 keV transitions connect the band head of the newly observed semi-dec with the 25/2^- and 29/2^- levels of the previously established semi-decoupled band