Tagungsberichte

Es wurde eine X-X-Fluoreszensmethode (mit einer 30-mCi-²³⁸ Pu-Anregungsquelle und einem Proportionalzähler) zur Bestimmung von eisenhaltigen Verschleiβteilchen in Schmierölen für Schiffsmotoren erarbeitet. Die Methode ermöglicht eine schnelle Abschātzung des Verschleiβes von Miotorteilen. Die Empfindlichkeit der Methode beträgt ca. 0,005% Fe, der mittlere Fehler (nach dem Student-Test bei einer Zuverlässigkeit von 0,95) ca. ±5%.     

Die Anwendung der “Neutronenhaubitze” zur Borbertimmung in Glas

Die bei der ¹⁰B (n, α) ⁷ Li-Reaktion entstehende prompte Strahlung von E_γ = 478 ke V bildet die Grundlage für zerstörungsfreie und quantitative Bestimmung von Bor in Glas. Es wird eine als “Neutronenhaubitze” bezeichnete Bestrahlungseinrichtung beschrieben, die mit einer ²¹¹ Am-Be-Neutronenquelle von 5 Ci ausgerüstet ist. Damit lassen sich bei 10 min Meβzeit im Konzentrationsbereich 5· · ·25 Masse-% Aanlysenfehler ∠2% relativ erreichen.     

Methane-Derived Carbonates in a Native Sulfur Deposit: Stable Isotope and Trace Element Discriminations Related to the Transformation of Aragonite to Calcite

Abstract

Stable isotope (¹³C, ¹⁸O, ³⁴S) and trace element (Sr²⁺, Mg²⁺, Mn²⁺, Ba²⁺, Na⁺) investigations of elemental sulfur, primary calcites and mixtures of aragonite with secondary, post-aragonitic calcite from sulfur-bearing limestones have provided new insights into the geochemistry of the mineral forming environment of the native sulfur deposit at Machów (SE-Poland). The carbon isotopic composition of carbonates (δ¹³C = ?41 to ?47‰ vs. PDB) associated with native sulfur (δ³⁴S = + 10 to + 15‰ vs. V-CDT) relates their formation to the microbiological anaerobic oxidation of methane and the reduction of sulfate derived from Miocene gypsum. From a comparison with experimentally derived fractionation factors the element ratios of the aqueous fluids responsible for carbonate formation are estimated. In agreement with field and laboratory observations, ratios near seawater composition are obtained for primary aragonite, whereas the fluids were relatively enriched in dissolved calcium during the formation of primary and secondary calcites. Based on the oxygen isotope composition of the carbonates (δ¹⁸O = ?3.9 to ?5.9‰ vs. PDB) and a secondary SrSO₄ (δ¹⁸O = + 20‰ vs. SMOW; δ³⁴S = + 59‰ vs. V-CDT), maximum formation temperatures of 35°C (carbonates) and 47°C (celestite) are obtained, in agreement with estimates for West Ukraine sulfur ores. The sulfur isotopic composition of elemental sulfur associated with carbonates points to intense microbial reduction of sulfate derived from Miocene gypsum (δ³⁴S ≈ + 23‰) prior to the re-oxidation of dissolved reduced sulfur species.     

Moderne Arbeitsgeräte für die Grobstrukturprüfung mit 192Ir

Die Radiogaschromatographie stellt eine ausgezeichnete Methode für die Reinheitskontrolle ¹⁴C-markierter Präparate dar. Es werden jedoch in der Literatur kaum Größen zur Charakterisierung der Detektorempfindlichkeit für die radiogaschromatographische Messung angegeben.     

Preface - Contributions to the 8th International Conference on Applications of Stable Isotope Techniques to Ecological Studies (ISOECOL), Brest,France, 20–24 August 2012

Abstract

The study is focused on the dolomite-limestone drinking water aquifers in the Bo? massif, as well as on the andesite-aquifer containing mineral water in the vicinity of Roga?ka Slatina. The catchment area is limited and both drinking and mineral waters are discharged from the same source. The increasing use of deeper aquifers means that natural springs and shallow wells have become sporadic. Consequently new techniques of investigating recharge and aquifer capacity are required which can augment classical hydrogeological methods.

Current research into the mineral and drinking water aquifers in the area of Roga?ka Slatina is based on measuring the isotopic composition of light elements, (H, C and O) as natural tracers. It can be concluded that all the groundwaters investigated are typically infiltrated meteoric water. The drinking waters are generally young and were infiltrated up to about ten years ago. The isotopic composition of oxygen is similar to recent precipitation (δ¹⁸O = -9.3 ± 1‰) and the drinking waters contain tritium. It was found that exploited mineral waters recharged aquifers during colder periods; they are only partly mixed with younger water as can be seen from the isotopic composition of oxygen and corrected ¹⁴C dating, which puts the mean ages at between around 100 and 8,000 years. With regard to the “nuclear period” (1960-64) with abnormally high tritium activities of precipitation, all the waters examined can be divided into at least three main infiltration groups depending on their measured tritium content: around 35 years old (> 80 T.U.), older (> 10 T.U.) and younger (10 to 60 T.U.). Detailed dating is possible following the above classification. Isotope exchange between rocks and water is negligible and therefore very deep circulation at the temperature conditions above 80°C does not occur. Dissolved inorganic carbon (DIC) in the drinking waters is the result of equilibrium reactions between carbonates and organically produced CO₂ (δ¹³C = - 14.5 ± ‰), while the high concentrations of DIC (δ¹³C = + 3 ±‰) and CO₂ observed in the mineral waters are generated by low-temperature decarbonatization processes and indicate the deep origin of CO₂, from where gas migrates into mineral water aquifers.

Correlation analyses between the parameters studied are performed. Useful conclusions concerning water circulation and the capacities of aquifer reservoirs are described which support the future optimal pumping of mineral and drinking water at the limited catchment area of Roga?ka Slatina and Bo?.     

Mit Radioquecksilber markierte Nuklearpharmaka. Präparation und Untersuchung über Zusammenhänge zwischen chemischer Konstitution und Organaffinität

Mit Radioquecksilber markierte organische Präparate haben eine groβe Bedeutung für die nuklearmedizinische Diagnostik, speziell für die statische Nierenszintigraphie. Nach Diskussion von Kriterien für die Entwicklung von Nuklearpharmaka wird auf die Pharmakologie und Biochemie quecksilberhaltiger Pharmaka eingegangen. Am Beispiel der beiden Präparate Chlormerodrin und Mersalyl wird dargelegt, welche Möglichkeiten für Synthesen zur Veränderung der chemischen Konstitution und damit der Pharmakokinetik bestehen. Zum Schluβ des ersten Teiles wird kurz auf die Oxymerkurierung von Olefinen eingegangen.     

Calcium isotope fractionation in liquid chromatography with crown ether resin in methanol medium

Breakthrough mode liquid chromatography was employed to investigate calcium (Ca) isotope fractionation in methanol medium. Highly porous silica beads, the inner pores of which were embedded with a benzo-18-crown-6 ether resin, were used as column packing material. Enrichment of heavier isotopes of Ca was observed in the frontal part of the respective Ca chromatograms. The values of the isotope fractionation coefficient (?) were in the order of 10^?3 at 25 °C. Use of methanol as solvent has little advantage over the aqueous system as far as the values of ? are concerned. However, a substantial improvement was observed concerning the adsorption capacity of the crown ether resin for Ca ions. Molecular orbital calculations supported the present isotopic results in a qualitative fashion.     

Eine Apparatur zur Messung natürlicher 4C-Aktivitäten

Aufbau, Arbeitsweise und Eigenschaften einer Apparatur, mit der naturliche ^l4C-Aktiviäten in Grund- und Oberflächenwässern gemessen werden können, werden beschrieben.

Die Messung erfordert 3 Arbeitsschritte: Probenahme, Synthese von Benzol, welches dann den Probenkohlenstoff enthält, und Messung der ¹⁴C-Aktivität in einem Flüssigkeitsszintillationszähler.

Die Apparatur kann zur Datierung von Wasserproben im Altersbereich zwischen 200 und 37000 a verwendet werden.     

Labelling,Fractionation and Toxicity of Scorpion (Leiurus quinquestriatus H and E) Venom,using 125I, 131I and Gel-Filtration Technique

Labelling the venom of scorpion was achieved by means of a technique previously published by the author. The radioisotopes, used were both ¹²⁵I and ¹³¹I in a nascent form. Fractionation was done by the use of Sephadex G-100. Both the radioactivity and the extinction curves denoted the presence of three well defined peaks. The toxicity of the first fraction was found to be the most lethal. While the second peak was in the magnitude of 20 percent of the first, the third peak proved to be nontoxic to mice up to a concentration of 6 mg/kg body weight.     

Production of Hippuran-131I at Boris Kidrič Institute,Viněa Part II. Investigation of the Stability of Sodium ortho-131I-Hippurate as a Function of the Ageing Time,Presence of some Bacteriostatics and Stabilizers,Radioactivity, and the Sterilization Process of its Solutions

Stability of radioactive sodium ortho-¹³¹I-hippurate produced at the Boris Kidri? Institute, Vin?a, according to the modified procedure for application in nuclear medicine in Yugoslavia was investigated.

In these investigations stability was observed as a function of the ageing time of the solutions, their radioactivity (A mCi/ml; A mCi/mg of the carrier; A_tot), the presence of some bacteriostatics and stabilizers (C₆H₅—CH₂OH, Na-citrate), sterilization process and storage conditions.