States on systems of sets that are closed under symmetric difference

We consider extensions of certain states. The states are defined on the systems of sets that are closed under the formation of the symmetric difference (concrete quantum logics). These systems can be viewed as certain set‐representable quantum logics enriched with the symmetric difference. We first show how the compactness argument allows us to extend states on Boolean algebras over such systems of sets. We then observe that the extensions are sometimes possible even for non‐Boolean situations. On the other hand, a difference‐closed system can be constructed such that even two‐valued states do not allow for extensions. Finally, we consider these questions in a σ‐complete setup and find a large class of such systems with rather interesting state properties.     

Solvent extraction of calcium and strontium into nitrobenzene by using hydrogen dicarbollylcobaltate in the presence of polypropylene glycol PPG 425

From extraction experiments and γ-activity measurements, the exchange extraction constants corresponding to the general equilibrium M⁺(aq) + Cs⁺(org) ⟺ M⁺(org) + Cs⁺(aq) taking place in the two-phase water–phenyltrifluoromethyl sulfone (abbrev. FS 13) system (M⁺ = Li⁺, H₃O⁺, Na⁺, NH₄⁺ \hbox{NH}_{4}{}^{+} , Ag⁺, Tl⁺, K⁺, Rb⁺; aq = aqueous phase, org = FS 13 phase) were evaluated. Furthermore, the individual extraction constants of the M⁺ cations in the mentioned two-phase system were calculated; they were found to increase in the series of Li⁺ < H₃O⁺ < Na⁺< NH₄ ⁺ \hbox{NH}_{4}{}^{ + } < Ag⁺ < Tl⁺ < K⁺ < Rb⁺ < Cs⁺.     

<Superscript>99m</Superscript>Tc-labeling and molecular modeling of short dipeptide glycyl-<Emphasis Type="SmallCaps">l</Emphasis>-proline

Glycyl-l-proline (Gly-l-Pro) is the main degradation product of collagen and is a good diagnostic tool in various pathological conditions. The aim of this work was to prepare dipeptide Gly-l-Pro labeled with ^99mTc. Complex preparation was carried out under alkaline reaction conditions and its stability was assessed 10 and 120 min after preparation. The formation of two types of complex compounds was observed. High-performance liquid chromatography, paper electrophoresis, paper chromatography and thin layer chromatography were employed to monitor the formation of different complexes. Molecular modeling (semi-empirical method) was used to design their structure and composition. First complex cI with formula [TcO(Gly-l-Pro)]⁻¹ is unstable. After 120 min cI is completely transformed to complex cII with formula Tc(Gly-l-Pro)₃.     

Synergistic extraction of europium and americium into nitrobenzene by using hydrogen dicarbollylcobaltate and 1,2-(diphenylphosphino)ethane dioxide

Extraction of microamounts of europium and americium by a nitrobenzene solution of hydrogen dicarbollylcobaltate (H⁺B⁻) in the presence of 1,2-(diphenylphosphino)ethane dioxide (DPPEtDO, L) has been investigated. The equilibrium data have been explained assuming that the species HL⁺, HL₂ ⁺, ML₂ ³⁺ and ML₄ ³⁺ (M³⁺ = Eu³⁺, Am³⁺) are extracted into the organic phase. The values of extraction and stability constants of the species in nitrobenzene saturated with water have been determined. It was found that the stability constants of the corresponding complexes EuL _n ³⁺ and AmL _n ³⁺, where n = 2, 4 and L is DPPEtDO, in water-saturated nitrobenzene are comparable.     

Sorption of cesium from water solutions on potassium nickel hexacyanoferrate-modified <Emphasis Type="Italic">Agaricus bisporus</Emphasis> mushroom biomass

In order to gain biosorbent that would have the ability to bind cesium ions from water solution effectively, potassium nickel hexacyanoferrate(II) (KNiFC) was incorporated into the mushroom biomass of Agaricus bisporus. Cesium sorption by KNIFC-modified A. bisporus biosorbent was observed in batch system, using radiotracer technique using ¹³⁷Cs radioisotope. Kinetic study showed that the cesium sorption was quite rapid and sorption equilibrium was attained within 1 h. Sorption kinetics of cesium was well described by pseudo-second order kinetics. Sorption equilibrium was the best described by Freundlich isotherm and the distribution coefficient was at interval 7,662–159 cm³ g⁻¹. Cesium sorption depended on initial pH of solution. Cesium sorption was very low at pH₀ 1.0–3.0. At initial pH 11.0, maximum sorption of cesium was found. Negative effect of monovalent (K⁺, Na⁺, NH₄ ⁺) and divalent (Ca²⁺, Mg²⁺) cations on cesium sorption was observed. Desorption experiments showed that 0.1 M potassium chloride is the most suitable desorption agent but the complete desorption of cesium ions from KNiFC-modifed biosorbent was not achieved.     

Infrared laser-produced carbon-phase shield to oxidation of nanosized titanium monoxide

Pulsed infrared laser-irradiation of titanium monoxide leads to ablation and when carried out in gaseous benzene (1-5 Torr) to simultaneous dielectric breakdown of benzene into low molecular carbonaceous species which allow carbothermal reduction of ablated TiO_x particles and their protection by carbonaceous shell. The deposited particles are characterized by Fourier transform infrared Raman and X-ray photoelectron spectroscopy and by electron microscopy and shown to be stable towards oxidation in air. The reported process can find use in protection of gas-phase produced reactive nanoparticles by carbon phase.     

Affinity capillary electrophoresis and density functional theory employed for the characterization of hexaarylbenzene-based receptor complexation with alkali metal ions

In this study, affinity capillary electrophoresis (ACE) and quantum mechanical density functional theory (DFT) calculations were combined to investigate non-covalent binding interactions between the hexaarylbenzene-based receptor (R) and alkali metal ions, Rb(+) and Cs(+) , in methanol. The apparent binding (stability) constants (K(b) ) of the complexes of receptor R with alkali metal ions in the methanolic medium were determined by ACE from the dependence of effective electrophoretic mobility of the receptor R on the concentration of Rb(+) and Cs(+) ions in the BGE using a non-linear regression analysis. The receptor R formed relatively strong complexes both with rubidium (log K(b) =4.04±0.21) and cesium ions (log K(b) =3.72±0.22). The structural characteristics of the above alkali metal ion complexes with the receptor R were described by ab initio density functional theory calculations. These calculations have shown that the studied cations bind to the receptor R because they synergistically interact with the polar ethereal fence and with the central benzene ring via cation-π interaction.     

Determination of phytic acid and inositolphosphates in barley

Phytic acid (PA) and lower inositolphosphates (InsP(n) ) is the main storage form of phosphorus in grains or seeds. The content of PA and InsP(n) in different varieties of barley was analyzed by capillary isotachophoresis and online-coupled capillary isotachophoresis with CZE. The electrolytes (in demineralized water) for the isotachophoretic analysis consisted of 10?mM HCl, 14?mM glycylglycine, and 0.1% 2-hydroxyethylcellulose (leading) and 10?mM citric acid (terminating). The optimized electrolytes for the online coupling isotachophoresis with zone electrophoresis analysis were mixtures of 5?mM HCl, 7?mM glycylglycine, and 0.1% 2-hydroxyethylcellulose (leading), 20?mM citric acid, 10?mM glycylglycine, and 0.1% 2-hydroxyethylcellulose (background) and 10?mM citric acid (terminating). PA and all studied InsP(n) were separated within 25?min and detected by a conductivity detector. Simple sample preparation (acidic extraction), sufficient sensitivity, speed of analysis, and low running cost are important attributes of the electrophoretic methods. The method was used for the determination of PA and InsP(n) in barley varieties within an ongoing research project.     

Solvent extraction of some divalent metal cations into nitrobenzene by using a synergistic mixture of strontium dicarbollylcobaltate and hexaethyl calix[6]arene hexaacetate

Extraction of microamounts of cesium by a nitrobenzene solution of hydrogen dicarbollylcobaltate (H⁺B⁻) in the presence of polypropylene glycol PPG 425 (L) has been investigated. The equilibrium data have been explained assuming that the complex species HL⁺ and CsL⁺ (L = PPG 425) are extracted into the organic phase. The values of extraction and stability constants of the cationic complex species in nitrobenzene saturated with water have been determined.     

Semiquinol and phenol compounds from seven <Emphasis Type="Italic">Senecio</Emphasis> species

In this paper, examination of the aerial parts of seven Senecio species from Serbia and Montenegro is reported. Phytochemical investigation of Senecio erucifolius led to the isolation and characterization of semiquinol butyl 2-(1-hydroxy-4-oxocyclohexa-2,5-dienyl)acetate (I), along with methyl 2-(1-hydroxy-4-oxocyclohexa-2,5-dienyl)acetate (jacaranone, II), and methyl 2-(4-hidroxyphenyl)acetate (III). The structure of I was established based on spectroscopic studies (¹H- and ¹³C-NMR, IR, and CI-MS). Compound II was also isolated from S. carpathicus and S. subalpinus. The presence of jacaranone in the methanol extracts of S. wagneri, S. othonnae, and S. paludosus was confirmed by LC/ESI-TOF MS.