The potential health hazard due to elevated radioactivity in old uranium mines in Dolina Białego,Tatra Mountains,Poland

Natural radioactivity is one of the essential components of the environment. Unlike the Sudety mountains area in Poland, the Tatra Mountains were not the subject of wide survey as regards the levels of natural radioactivity. Especially, the concentrations of radon (natural radioactive gas) have not been investigated there in terms of their possible negative health impact. Within the frame of bilateral cooperation between the Institute of Nuclear Physics in Kraków, Poland, and the Jo?ef Stefan Institute in Ljubljana, Slovenia, the measurements of natural radioactive elements in old uranium mines in the Tatra National Park were performed in June 2010. The investigated sites were located in Dolina Bia?ego (The Valley of the White). One of the mines is situated near the tourist path. The paper presents the results of complex measurements of natural radioactivity in both uranium drifts. The concentration of radon gas inside the mining drifts exceeded 28,000 Bq m^?3. Also, very high gamma dose rates were observed (up to 5600 nSv h^?1). The maximum concentrations of natural radioactive elements (potassium ⁴⁰K, radium ²²⁶Ra, thorium ²³²Th) in rock samples amounted to 535, 2137, and 18 Bq kg^?1, respectively. The effective dose rates due to radon and thoron inhalation have been assessed as 0.013 mSv h^?1 (for the lowest concentration) and 0.121 mSv h^?1 (for the highest concentration).     

Distance-Balanced Graphs

Distance-balanced graphs are introduced as graphs in which every edge uv has the following property The number of vertices closer to u than to v is equal to the number of vertices closer to v than to u. Basic properties of these graphs are obtained. The new concept is connected with symmetry conditions in graphs and local operations on graphs are studied with respect to it. Distance-balanced Cartesian and lexicographic products of graphs are also characterized. Several open problems are posed along the way. Received August 31, 2005     

Efficiency and characteristics of solid-phase (ion-exchange) extraction for removal of Cl- matrix

Certain types of samples contain chloride in concentrations that are too high to accurately determine other anions by ion chromatography without any pretreatment. One of the most widely used approaches for such samples is matrix elimination using disposable cartridges containing a cation-exchange resin in the Ag+ form. The efficiency and characteristics of the commercially available cartridge for Cl- removal were tested by the on-line connection of the cartridge effluent to an inductively coupled plasma mass spectrometer. Displacement efficiency of Ag+ ions and loading capacity of the cartridges were studied at different flow-rates. Significant amounts of silver were detected in the effluent, which were attributed to colloidal AgCl as well as dissolved Ag+ ions. Because silver ions can cause irreversible damage to the analytical column, an Ag cartridge followed by an on line filter (pore size 0.22 microm) and cartridge in the H3O+ form were proposed for improvement of this sample pretreatment technique for chloride removal.     

Determination of jasmonic acid in <Emphasis Type="Italic">Lemna minor</Emphasis> (L.) by liquid chromatography with fluorescence detection

A new method is described for the determination of endogenous jasmonic acid (JA) in Lemna minor plant extracts using liquid chromatography (LC) with fluorescence detection. Plant tissues were extracted and derivatised using 9-anthryldiazomethane (ADAM reagent) prepared in situ. Accuracy and precision were improved by using the internal standard dihydrojasmonic acid (dh-JA) for the correction of JA losses during sample preparation steps. Liquid chromatography–mass spectrometry (LC/MS) analysis of ADAM derivatives of JA and dh-JA confirmed that a single molecule of JA and dh-JA was coupled with one molecule of reagent. Derivatives of JA and dh-JA were separated with gradient elution on a C₁₈ reversed-phase column using acetonitrile/water as a mobile phase and detected by a fluorescence detector at excitation and emission wavelengths of 254 and 412 nm, respectively. The detection limits of JA and dh-JA were 2.9 ng mL⁻¹ and 3.7 ng mL⁻¹ per 50-μL injection. The method is reproducible and selective and yields single peaks for each compound regardless of isomer. The specificity and accuracy of the proposed LC/FD method was confirmed by liquid chromatography–TurboIon Spray tandem mass spectrometric (LC/MS/MS) analysis of free JA in Lemna minor samples under multiple reaction monitoring conditions.     

Amine Functionalisations of Glycidyl methacrylate Based PolyHIPE Monoliths

High internal phase emulsions were employed to prepare highly porous (up to 80% pore volume) monoliths of poly(glycidyl methacrylate-co-ethylenegycol dimethacrylate) by free radical polymerisations of continuous phases of emulsions. Monoliths with cavities approximately 4 µm in diameter and with interconnecting pores approximately 0.7 µm in diameter were obtained. In order to obtain monoliths with ion exchange groups on the surface of pores for chromatography applications, functionalisations with different amines were performed and various reaction conditions tested. FTIR spectroscopy and nitrogen content analysis were used to monitor the functionalisation processes. Monoliths were succesfully functionalised with 1,2-diaminoethane, 1,4-diaminobuthane, 1,8-diaminooctane and tris(diethylamino)amine.     

meso‐N,N′‐Oxalyl­divaline

The title compound, 2,2′‐(oxalyldiimino)bis(3‐methylbutanoic acid), C₁₂H₂₀N₂O₆, possesses a centre of symmetry. In the crystal, mol­ecules are connected by hydrogen bonds between ox­amide and carboxyl groups, similar to the pattern of the monoclinic forms of HO–Gly–CO–CO–Gly–OH and HO–Aib–CO–CO–Aib–OH (Gly is glycine and Aib is 2‐amino­isobutyric acid). The characteristic torsion angles in the title compound are close to those in peptide α‐helices.     

Interaction of cetylpyridinium chloride with giant lipid vesicles

The interaction of cationic surfactant cetylpyridinium chloride, CPC, with giant lipid vesicles prepared from 1-palmitoyl-2-oleoylphosphatidylcholine, POPC, was examined at various concentrations of the lipid component. The lipid concentration was determined by a spectrophotometric method. The potentiometric method based on surfactant-selective electrode was used for the determination of surfactant concentration in the external water solution. From these results, moles of surfactant incorporated in the membrane per mole of lipid (parameter beta) and two kinds of partition coefficients were calculated. Their values were found to be considerably larger than the available literature data. A three stage process of surfactant-induced solubilization of lipid vesicles was observed. First, stable mixed bilayers form, which become saturated with CPC at a value beta(sat) larger than 0.8, which then gradually disintegrate. Just prior to the breakdown of the vesicular structure, formation of ellipsoidal vesicles was observed by optical microscopy. This phenomenon was attributed to the cooperative incorporation of surfactant into the bilayer. Fluorescence measurements have shown that the second stage in the solubilization process of POPC by the C16 chain-length surfactant does not involve mixed micelles. These are formed only in the third stage, which is the complete solubilization of POPC bilayers. The corresponding critical micellization concentration decreases with increasing concentration of the lipid component.     

Intermolecular contacts in the crystal packing of 2,2′‐(N,N′‐oxalyldiimino)­bis(3‐phenyl­propanamide) di­methyl sulfoxide solvate

In the title compound, C₂₀H₂₂N₄O₄·C₂H₆OS, two distinct hydrogen‐bond systems connect oxal­amide groups in one pattern and primary amide groups in the other to form a two‐dimensional network perpendicular to the c axis. These hydro­philic layers are joined to the three‐dimensional structure through C—H?π interactions. The hydrogen‐bonded waved layers shape holes which are occupied by disordered di­methyl sulfoxide solvent mol­ecules.