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Water pollution is a constant challenge for humanity. Sustainable economic development and environmental protection through a green economy structure provide the opportunity to project a model of scientific, social, and economic flows. Considering new chemical use in water treatment, we tested two β-diketonates that we previously synthesized in the reaction between methyl ketone and diethyl oxalate under basic conditions. For water treatment, we used the appropriate salts of the mentioned compounds due to better solubility in water. In cooperation with the partner organizations PUC (public utility companies) Kragujevac, LTD (Private Limited Company), "Rudnik," and FIAT (Fabbrica Italiana Automobili Torino), we conducted research on their wastewater treatment. The results appeared to be more convincing in practice than the conventional methods. As a result of the study, no negative effects exerted on living organisms were found. Therefore, we are on the right track for potential application in the treatment of drinking water. Appropriate β-diketonates were tested on twelve microorganisms (isolates from the wastewater and standard strains of bacteria and yeast). One of the two tested compounds showed promising antimicrobial activity. Further investigations showed that the tested compounds significantly reduce the concentration of heavy metals, which was confirmed by statistical calculations. Also, the main advantage of this method is a small volume of waste requiring disposal, no need for driving off excess moisture, used recyclability of the coagulants, reducing hazardous waste, and therefore reducing the costs for water treatment.

The aim of this study was to determine the bioaccumulation of the metals in Rumex acetosella L. collected from the tailings of abandoned mine in Žitkovac (near Kosovska Mitrovica, Kosovo and Metohija), and to establish the possibility of using those plants for medicinal purposes. Concentrations of heavy metals (Mn, Fe, Pb, Ni, Cr, Cu, Cd, Zn, Ca and Mg) in soil, roots and aboveground parts of R. acetosella were determined by wet mineralization with nitric and perchloric acid. The results of the research indicate that R. acetosella accumulates large amounts of Ni, Cu, Pb, Zn, Cr, and Mn. The total phenol content, the total amount of flavonoids and the antioxidant activity of three different extracts of the root and aboveground parts of R. acetosella were determined by spectrophotometric methods. The acetone extracts contain the highest concentration of phenols and flavonoids. Ethyl acetate has proven to be a solvent that releases the least amount of phenols and flavonoids. The methanol extract of aboveground parts has the highest, while acetone root extract has the lowest antioxidant activity. Rumex acetosella can be used for medicinal purposes, but only collected from uncontaminated soil.

Stark broadening parameters - full widths at half maximum (FWHM) and shifts for 11 Re II lines have been calculated. The plasma parameters used were electron density of 1017 cm−3 and temperature from 5 000 K to 80 000 K. Calculations were performed using the simplified modified semiempirical (SMSE) approach and compared with calculations by Cowley’s approximative Stark broadening formula at 10000 K, usefull in spectrum synthesis. The results have also been considered in the atmosphere model of A type star and for DB white dwarfs.

The study investigates mosses (Hypnum cupressiforme Hedw.) as bioindicators of pollution in three non-urban mountain areas of northern Kosovo and Metohija regions. Concentrations of radionuclides and metals were measured in moss and soil samples. 137Cs specific activities in soil were strongly correlated with organic matter content. 137Cs in mosses was significantly higher in coniferous than in deciduous forests. 7Be measured in moss samples was increasing with altitude. Concentrations of Ni, Cr, Cu and Zn exceeded regulatory limits in many soil samples from two mountains (Kopaonik and Rogozna). However, concentrations of elements in mosses were weakly correlated with those in soil.

In this work, we present the data of Stark widths of rare-earth element Nb iii, calculated for 21 spectral lines by using the modified semi-empirical method. Obtained results have been used to study the influence of Stark broadening on spectral lines in hot stars atmospheres such as A-type star and DA and DB white dwarfs.

The aim of this study was to determine the concentration of some metals (Ca, Mg, Mn, Fe, Zn, Ni, Cr, Cd) in the soil and species of Tussilago farfara L. and Clematis vitalba L. on the tailings and flotation of the mine DOO "Rudnik". Concentrations in the soil were: Pb and Cu - higher than the maximum allowed, limit and remediation values; Cd, Cr and Ni - higher than the maximum allowed and limit values, and Zn higher than the limit values (according to the regulations of the Republic of Serbia). Better bioaccumulation of all tested metals was shown by T. farfara species, especially leaves for Zn. The results indicate the possible use of aboveground parts of both plant species in the revitalization of tailings by bioaccumulation of tested metals.

This research aimed to investigate the quality of drinking water from the rural area of village Pajsijević (Šumadija, central Serbia). The water is consumed as raw since it is not purified or chlorinated before consumption. The water was collected at three sampling points – in the spring of Kotlenik Mountain stream (W1 sample), in the local reservoir (W2 sample), and from the tap (W3 sample). Also, the sediment samples (soil and sand) were analyzed, too. The health risks related to the presence and concentration of some major and trace elements (Ca, Cr, Cu, Fe, Mg, Mn, Ni, Zn) and N, NO, NN3, NH4, P, P2O5, and PO4 were evaluated. Additionally, the presence and the number of total coliform bacteria and Escherichia coli (as an indicator of fecal contamination) were evaluated. The concentrations of analyzed major and trace elements in all water samples were below those at which toxic effects may occur. The exception was the concentrations of Fe (2.02 – 2012 mg/L), which were higher than is allowed. The origin of Fe in water is from sediment (soil and sand), which also showed high content of Fe (3006.0 mg/g and 2229.9 mg/g, respectively). The results of the Colorimetric test indicated the presence of coliform bacteria as well as the presence of E. coli in all water samples. Further research needs to include characterization of isolated coliform bacteria and serological investigation of E. coli strains in order to evaluate the risks of consumption related to waterborne illness.

Achillea millefolium L. has a great value as medicinal plant. The aim of the research is to determine the uptake potential for heavy metals and the intraspecial difference between unique species of A. millefolium from different localities based on the heavy metals uptake, their distribution in plant organs and enrichment factors. The results showed that plants growing on soil rich in heavy metals (tailings) absorb significantly higher amounts of metals compared to plants from the Ovčar-Kablar gorge (non-contaminated soil).

The limited reserves and well-known disadvantages of using fossil energy sources have increased the need for appropriate renewable substitutes in the production of various chemicals and materials. Biomass has been shown to be worthy of attention since it can be converted to biofuels and value-added chemicals relatively easily. The design of biomass valorisation process requires knowledge on the thermodynamic behaviour of the biomass-derived compounds, such as furfural and furfuryl alcohol. The thermodynamic and transport properties of the binary system furfural + furfuryl alcohol were studied at various temperatures and pressures. Density, speed of sound and refractive index were measured in the temperature range T = (288.15–345.15) K and viscosity was measured at temperatures up to 373.15 K, all at atmospheric pressure. Further, the density of pure components was obtained in the temperature range (293.15–413.15) K for furfural and (293.15–373.15) K for furfuryl alcohol at pressures up to 60.0 MPa. The obtained density values were correlated using the modified Tammann–Tait equation with an average absolute deviation lower than 0.009% for furfural and furfuryl alcohol. The optimised parameters were used for the calculation of the isothermal compressibility, the isobaric thermal expansivity, the internal pressure and the isobaric and isochoric specific heat capacities. The reported data are a valuable source of information for the further application of the investigated compounds.

International audience; Quasi-thermal noise (QTN) spectroscopy has been extensively used as an accurate tool to measure electron density and temperature in space plasmas. If the antenna length to radius ratio is sufficiently large, a typical measured spectrum clearly shows a resonance at the electron plasma frequency and a lower frequency plateau that quantify the electron distributions. The Wind spacecraft, with its long, thin antennas, is considered the mission par excellence for the implementation of the QTN method. However, a major issue in applying QTN spectroscopy is contamination from signals other than the ubiquitous plasma noise in the vicinity of plasma frequency, affecting the measured spectra and confusing their physical interpretation. In this work, we present a new method for selecting the observations of uncontaminated QTN, distinguishing it from other plasma and spacecraft effects. The selected measurements are used to obtain accurate values for both thermal and suprathermal electron parameters. Testing of the method on 1.5M observations under various conditions in the solar wind, including slow and fast wind and solar transients, confirms the reliability and accuracy of the method with no systematic flaws.

Paper description: ● Phenolic compounds have the properties of allelochemicals that cause radicle growth inhibition of herbaceous plant species. ● Phenolic compounds, as potential allelochemicals derived from woody plant species growing on fly ash deposits, were investigated. ● The chemical characteristics of substrates in allelopathic plant relationships could be useful in understanding the impact of ecological factors on plant allelopathic activity as they influence invasive plants during initiation of the pedogenetic process of sterile substrate, such as fly ash. Abs tract: The objective of this study was to determine the allelopathic potential of Robinia pseudoacacia L., Ailanthus altissima (Mill.) Swingle and Amorpha fruticosa L. that grow on the fly-ash deposits at the “Nikola Tesla – A” thermoelectric power plant in Obrenovac. The chemical characteristics of fly ash, such as pH, electrical conductivity (EC), content of carbon (C) and nitrogen (N), contents of available phosphorus (P 2 O 5 ) and potassium (K 2 O), the contents of total and available Fe, Cu, Mn, Ni and Zn as well as of phenolic acids (3,5 dihydroxybenzoic acid (3,5-DHBA) and ferulic acid) and flavonoids (rutin and quercetin) were analyzed in control fly ash (bare zones without vegetation cover) and plant rhizospheric fly ash. In order to determine the allelopathic activity of phenolic compounds in fly ash, modified soil sandwich allelopathic biotests were performed, and Trifolium pratense L. (red clover) was used as the indicator species. A. fruticosa showed the highest allelopathic activity, followed by A. altissima whereas R. pseudoacacia showed the lowest allelopathic potential. Negative correlation was noted between radicle and hypocotyl growth inhibition of red clover and the pH of fly ash. Positive correlations were found between radicle growth inhibition and the content of C, P 2 O 5 , total concentrations of Cu, available concentrations of Mn and Ni, the contents of ferulic acid, 3,5-DHBA, and rutin. Our results indicate that A. fruticosa and A. altissima increased the content of phenolics in fly ash, which can act as allelochemicals leading to radicle growth inhibition of red clover in the pioneer plant community on fly-ash deposits. These woody species that colonized fly-ash deposits can initiate the beginning of pedogenetic processes altering the ecosystem processes at degraded sites. https://doi.org/10.2298/ABS180823050G Received : August 23, 2018; Revised : October 12, 2018; Accepted : October 17, 2018; Published online: November 7, 2018 How to cite this article: Grbovic F, Gajic G, Brankovic S, Simic Z, Ciric A, Rakonjac Lj, Pavlovic P, Topuzovic M. Allelopathic potential of selected woody species growing on fly-ash deposits. Arch Biol Sci. 2019;71(1):83-94.

Woody plants are increasingly used in the remediation of contaminated land. The content of metals (Mn, Fe, Cu, Zn, Cr, Ca, Mg) was analyzed in the plant species Populus nigra L. and Populus tremula L. and in the soil on which they grow. The aim of the research was to determine differences between these two species based on the content of metals in plant organs (sprouts and leaves) and bioaccumulation potential and point out the potential application of these species in phytoremediation. Atomic absorption spectrometry was used to measure these heavy metals in soil and plant material. The results showed that P. tremula was a better metal accumulator because it absorbed larger quantities of Mn, Fe, Cu and Zn from P. nigra. P. nigra absorbed more chromium than P. tremula. Both species proved to be good zinc accumulators, and better bioaccumulation potential was found in P. tremula of P. nigra, although aspen had a strong negative correlation with Zn.

Densities, viscosities, speeds of sound and refractive indices have beenmeasured for the ternary systemethyl oleate+ n-hexadecane+1-butanol, and for the corresponding binaries ethyl oleate+1-butanol and ethyl oleate+ n-hexadecane, in the temperature range fromT=(293.15 to 343.15) K and at atmospheric pressure. Experimental data were employed to calculate some derived thermodynamic parameters, i.e. excess molar volumes (V-E), viscosity deviations (Delta eta.) and deviations in refractive index (.nD). Additionally, molar excess Gibbs free energies of activation of viscous flow (Delta G*(E)) and deviations in isentropic compressibility (Delta kappa(s)) were calculated. A graphical representation of excess molar volumes and refractive indices show positive deviation from ideal behavior for both binary systems whereas deviation in viscosity shows negative nature for the ethyl oleate + n-hexadecane system and an inversion sign for ethyl oleate +1-butanol binary system. A negative deviation in isentropic compressibility was confirmed for the systems ethyl oleate +1-butanol while positive deviation was observed in ethyl oleate + n-hexadecane system. It can be concluded that dispersive forces predominate between the components in binary systems and the observed behavior seems to suggest that the properties obtained for the ternary mixture are dominated by the binary effects. The viscosities of the binary systems were modeled by UNIFAC-VISCO, ASOG-VISCO, Teja-Rice and McAllister models. The results showed that McAllister's multibodymodel is suitable to describe viscosities for binary systemswithmaximumpercentage deviations less than 0.5%.

We present an analysis of hydrogen Balmer line shapes observed in two white dwarf spectra. One spectrum presents singlet lines while the second one presents lines with a triplet structure. The latter is a feature of the presence of a strong magnetic field. Using both Stark and Zeeman effects, we infer the density and the magnetic field. Our line shape calculations employ a computer simulation technique. The radiative transfer is accounted for through a onedimensional slab model.

International audience; Stark broadening parameters, line width and shift, are needed for investigations, analysis and modelling of astrophysical, laboratory, laser produced and technological plasmas. Especially in astrophysics, due to constantly increasing resolution of satellite borne spectrographs, and large terrestrial telescopes, data on trace elements, which were previously insignificant, now have increasing importance. Using the modified semiempirical method of Dimitrijević and Konjević, here, Stark widths have been calculated for 2 Se IV, 6 Sn IV, 2 Sb IV and 1 Te IV transitions. Results have been compared with existing theoretical data for Sn IV. Obtained results will be implemented in the STARK-B database, which is also a part of Virtual atomic and molecular data center (VAMDC).

The construction, general performance characteristics and analytical application of a titanium dioxide–modified carbon paste electrode sensitive to hydrogen ions, based on incorporation of titanium dioxide in a carbon paste matrix, is described. The proposed electrochemical sensor exhibits a linear response in the pH range from 2 to 10, at 25 °C, with a sub-Nernstian slope. The value of a slope is in a direct correlation with the electrode composition – the optimum content of a titanium dioxide in carbon paste is 30 %. Titanium dioxide-modified carbon paste electrode shows fast response time and reproducibility, confirmed by different compounds determination in both, individual and complex material, namely, in synthetic and real samples. Besides, the electrode shows high selectivity in the presence of the alkali and the alkaline earth ions as Na+, K+, Ca2+ or Mg2+. The standard deviation of the investigated acids (acetic, oxalic, 5-sulfosalicylic, p-toluensulfonic acid, and amino acid-glycine) and bases (N,N′-diphenylguanidine and collidine) is less than 1.3 %. The obtained data are compared with those obtained by using a conventional glass pH-electrode under the same experimental conditions and indicate a high correlation between them.

Stark widths for 18 Zr IV spectral lines have been calculated by using the modified semi-empirical method. The obtained results have been used to investigate the influence of Stark broadening on the spectra of atmospheres of chemically peculiar stars of A spectral type and hydrogen-rich DA and helium-rich DB white dwarfs. Our results have been used also to test possibility to predict new data using some approximate methods developed on the basis on regularities and systematic trends.

Electrochemical characterization of palladium electrode has been reported. The investigated electrode showed a linear dynamic response for p-toluensulfonic acid and iodide ions in the concentrations range between 5 × 10−1 and 1 × 10−5 mol L−1 with a Nernstian slope of 55 mV for p-toluensulfonic acid and 63 mV per decade for iodide ions in water, as well as 53 mV for p-toluensulfonic acid and 51 mV per decade for iodide ions in dioxane. The response time of the electrodes was less than 10 s in the used solvents. Some potential analytical applications of the sensors have been pointed. Palladium electrode for the potentiometric titrations of acids (citric, barbituric, and p-toluensulfonic acid), bases (N,N’-diphenylguanidine, tributylamine, and 2,2'–bipyridine), halides, and some real samples in aqueous and non-aqueous solutions were studied. Тetrabutylammonium hydroxide, perchloric acid, and silver nitrate proved to be very suitable titrating agents for these titrations. The standard deviation of the determination of the investigated compounds was less than 0.9 % from those obtained with a glass electrode, i.e., silver electrode.

Elevated heavy metal concentrations cause environmental pollution. Our study examines the content of heavy metals (Pb, Ni, Mn, Fe and Cu) in the aboveground parts of Polygonum aviculare L. (Polygonaceae) sampled from five different locat ions in the city of Kraljevo and its surroundings. In order to evaluate the bioindicative ability of P. aviculare we have chosen localities which had different level of contamination. The analysis of heavy metals in the plant material was conducted by atomic absorption spectrophotometry. There is a correlation between t he higher concentrations of Pb, Cu, Ni, Mn and Fe measured in plant tissues and environmental pollution caused by traffic. Other emission sources and soil composition are considere d to be an important influence on the quantity of metals in plants. Based on the results, the species P. aviculare can be used as an important bioindicator of habitat pollution by heav y metals.

The purpose of this comparative analysis is the determination of the total quantity of metals (Mg, Ca, K, Ni, Fe, Mn, Zn, Cu, Cr and Pb) in soil samples, above ground plant parts and tea made of plants Teucrium montanum and T. chamaedrys from different serpentine and calcareous habitats as well as of the total quantity of phenolic compounds and antioxidant activity. The obtained results showed that the quantities of certain metals (Mg, Fe, Ni and Mn) in the soil from the serpentine habitats were greater in comparison with other metals (Ca, Zn and Pb) which were more frequently found in the soil from the calcareous habitats. The results demonstrated that the analysed plant samples from the serpentine habitats contained higher quantity of Fe, Ni and Cr as opposed to the plant samples from the calcareous habitats which contained greater quantity of Ca and Zn. Although the studied species accumulate analysed metals in different quantities, depending on the substrate type, they are not hyperaccumulators of these metals. The use of these species from serpentine habitats for tea preparation is safe to a great extent, because in spite of the determined metal absorption by plant organs, the tea does not contain dangerous quantity of heavy metals. The results showed greater total quantity of phenolic compounds and the higher level of antioxidant activity in the plant samples from serpentine habitats in comparison with the samples from calcareous habitats, which is an indicator of one of the mechanisms of adaptation to the serpentine habitat conditions.

International audience; White dwarfs with magnetic field strengths larger than 10 T are understood to represent more than 10% of the total population of white dwarfs. The presence of such strong magnetic fields is clearly indicated by the Zeeman triplet structure visible on absorption lines. In this work, we discuss the line broadening mechanisms and focus on the sensitivity of hydrogen lines on the magnetic field. We perform new calculations in conditions relevant to magnetized DA stellar atmospheres using models inspired from magnetic fusion plasma spectroscopy. A white dwarf spectrum from the Sloan Digital Sky Survey (SDSS) database is analyzed. An effective temperature is provided by an adjustment of the background radiation with a Planck function, and the magnetic field is inferred from absorption lines presenting a Zeeman triplet structure. An order-of-magnitude estimate for the electron density is also performed from Stark broadening analysis

Sodium is a very important element for the research and analysis of astrophysical, laboratory, and technological plasmas, but neither theoretical nor experimental data on Stark broadening of Na IV spectral lines are present in the literature. Using the modified semiempirical method of Dimitrijević and Konjević, here Stark widths have been calculated for nine Na IV transitions. Na IV belongs to the oxygen isoelectronic sequence, and we have calculated Stark widths belonging to singlets, triplets, and quintuplets, as well as with different parent terms. This is used to discuss similarities within one transition array with different multiplicities and parent terms. Additionally, calculated widths will be implemented in the STARK-B database (http://stark-b.obspm.fr) which is also a part of the Virtual Atomic and Molecular Data Center (VAMDC—http://www.vamdc.org/).

Stark broadening parameters for 157 multiplets of helium like boron (B IV) have been calculated using the impact semiclassical perturbation formalism. Obtained results have been used to investigate the regularities within spectral series. An example of the influence of Stark broadening on B IV lines in DO white dwarfs is given., 6 pages, 2 figures

The construction and general performance characteristics of a novel potentiometric electrode responsives to hydrogen (lyonium/lyate) ions are described. This sensor is based on the use of the magnetite mineral as the working surface of the electrode. The sensor exhibits fast, stable and sub-Nernstian for the p -toluenesulphonic acid over the concentration range 1 × 10 −1 to 1 × 10 −3 M at 25 °C with slope of 39.3 ± 0.6 and 41.0 ± 0.5 per concentration decade in propylene carbonate and γ-butyrolactone, respectively. The response time is 13 and 15 s in the same order in both solvents. The change in the electrode potential from the acidic to basic region was 375 to −75 mV in γ-butyrolactone and 394 to 6 mV in propylene carbonate. The determination of 25–30 mg of some important organic acids (benzoic, anthranilic, and salicylic acid) in non-aqueous media shows an average recovery of 100.2% and 99.8% with relative standard deviation of 0.17–0.47% in both solvents. Potentiometric titrations of acids involving potassium hydroxide as titrant are monitored in both solvents with inflection point from 207 to 109 mV.

Electrochemical characterization of palladium and platinum oxide electrodes is reported. Palladium (platinum) oxide layer has been formed by thermal oxidation of smooth Pd(Pt) electrode. The palladium/palladium oxide electrode enables fast measurements, with good sensitivity of 54 ± 0.9 mV per decade, in acidic and base solutions (linear range of response up to the concentration 1 × 10−6 M) in acetonitrile and 49 ± 1.2 mV per decade in propionitrile. The response of the platinum/platinum oxide was linear in the concentration range between 5 × 10−2 and 1 × 10−6 M, and a sensitivity of 52 ± 1.6 mV per decade in acetonitrile was obtained. The response time of the electrodes was less than 15 s in the both solvents. The properties of the palladium oxide electrode were similar to those of the platinum one. Some potential analytical applications of the sensors are pointed. Palladium and platinum oxide electrodes for the potentiometric titrations of acids (benzoic, anthranilic, salicylic acids, and sulfadiazine) and bases (N,N'-diphenylguanidine, tributylamine, and collidine) in acetonitrile and propionitrile were studied. Potassium hydroxide, tetrabutylammonium hydroxide and perchloric acid proved to be very suitable titrating agents for these titrations. The standard deviation of the determination of the investigated acids and bases was less than 0.7% from those obtained with a glass electrode. The electrodes have the following advantages: fast response, and reproducibility, the service life is long and without considerable divergence in potentials, the manufacture is simple, the production cost is low.

A novel acid–base sensor based on the natural mineral arsenopyrite for titrations in γ-butyrolactone and propylene carbonate is validated and studied. This sensor, which requires only small sample volumes, was employed for the titrations of some important organic acids (benzoic, anthranilic, and salicylic acid) with potassium hydroxide. A stable stationary potential was attained at the arsenopyrite electrode in γ-butyrolactone and propylene carbonate in less than 5 min. The change in the electrode potential from the acidic to basic region was 379 to −160 mV in γ-butyrolactone and 434 to −67 mV in propylene carbonate. The arsenopyrite electrode showed a relatively fast response time in the investigated solvents (11 s in γ-butyrolactone and 14 s in propylene carbonate). It can be used without any time limit or without considerable divergence in the potential. The investigated electrode showed a linear dynamic response for p-toluenesulfonic acid concentrations in the range 0.1–0.001 M, and a sub-Nernst dependence in γ-butyrolactone as well as in propylene carbonate. Unlike traditional pH titration, an end-point color indicator is unnecessary in this method, and real-time monitoring can be realized. The relative standard deviations for measurements of benzoic, anthranilic, and salicylic acids were 0.10–0.31%, which show that the repeatability and accuracy of measurements taken with the sensor are satisfactory.

Based on the cyclic voltammetric method, in the present study we have employed carbon paste for arsenopyrite mineral characterization in non-aqueous solution. Arsenopyrite yields well-defined cyclic voltammetric responses with well-defined oxidation (in the potential region from −0.7 to 0.7 V, versus Ag/AgCl) and reduction (from −1.0 to 0.8 V) peaks using this electrode. In addition, arsenopyrite mineral was studied as a new indicator electrode for the potentiometric titrations of acids (benzoic, anthranilic and salicylic acids) and bases (N,N′-diphenylguanidine, tributylamine and collidine) in acetonitrile and propionitrile. Potassium hydroxide, tetrabutylammonium hydroxide (TBAH) and perchloric acid proved to be very suitable titrating agents for these titrations. The investigated electrode showed a linear dynamic response for p-toluenesulfonic acid concentrations in the range 0.1–0.001 M, with a Nernstian slope of 38.5 mV in acetonitrile and 44.6 mV in propionitrile. The electrode showed a relatively fast response time and can be used without any time limit or without considerable divergence in potentials. The response time of the electrode was less than 10 s in both solvents. The standard deviation of the determination of the investigated acids and bases was less than 0.6% from those obtained with a glass electrode. The advantages of the electrodes are long-term stability, fast response and reproducibility, while the sensors are easy to prepare and are of low cost.

With the development of astronomical observations from space, spectral lines of trace elements can now be observed in stellar spectra with good resolution, and atomic data for such atoms and ions have an increasing significance. We review here work in Belgrade on the influence of Stark broadening of trace elements on stellar spectra and present new determinations of Stark broadening parameters of neutral tellurium. Also the corresponding Stark and Doppler widths are compared in atmospheres of A type stars.

International audience; Large differences between previous calculations of the Mn II spectral line Stark widths [Popovic, L.C., Dimitrijevic, M.S., 1997a. A&AS 128, 203; Popovic, L.C., Dimitrijevic, M.S., 1997b. SAJ 156, 173] and a recent experiment by [Djenize, S., Bukvic, S., Sreckovic, A., Nikolic, Z., 2006. NewA 11, 256] are considered. In order to do so, new semiclassical perturbation calculations of the Stark broadening parameters of three spectral lines within Mn II 3d 54s a 7S-3d 54p z 7P o and three within Mn II 3d 54s a 5S-3d 54p z 5P o multiplets, are performed. The influence of hfs on the Stark broadening parameters determination as a possible reason of disagreement is also discussed, on the example of Mn II 260.6455 nm and 259.4497 nm lines. Namely, measured and calculated values taking into account the hfs effect are compared. We found that this effect cannot explain the large discrepancy between experiment and theory. Other possible reasons for disagreement like the configuration interaction are discussed as well. The new semiclassical perturbation calculations, more sophisticated than previous ones, performed by using the modified semiempirical theory, are in better agreement with experiment, but a large difference up to a factor 2.39 for the width, still exist.

The electron-impact widths for 27 Lu III spectral lines have been calculated by using the modified semiempirical method. Calculations have been also performed with the published relativistic Hartree-Fock oscillator strengths and additionally, with the approximate formula of Cowley. With the obtained results, the influence of Stark broadening on Lu III lines was investigated in the spectra of A-type stars. The obtained data will be included in the STARK-B database, which is part of the Virtual Atomic and Molecular Data Center - VAMDC.

In order to complete Stark broadening data for Ne I spectral lines which are needed for analysis of stellar atmospheres, collisional widths and shifts (the so-called Stark broadening parameters) of 29 isolated spectral lines of neutral neon have been determined within the impact semiclassical perturbation method. Calculations have been performed for the broadening by collisions with electrons, protons and ionized helium for astrophysical applications, and for collisions with ionized neon and argon for laboratory plasma diagnostics. The shifts have been compared with existing experimental values. The obtained data will be included in the STARK-B database, which is a part of the Virtual Atomic and Molecular Data Center - VAMDC.

5-Alkenyl hydantoins are converted into bycyclic or tricyclic hydantoins under indirect electrochemical conditions generating selenium cations. Regiospecific 5-exo ring closure process occurred. The reactions proceeded in good yields and the influence of electrochemical conditions on diastereoselectivity of the reactions are investigated.

Stark broadening parameters have been calculated for 60 spectral lines of Xe VIII, for broadening by electron, proton, and He III impacts. For calculations, the semiclassical perturbation approach in the impact approximation has been used. The widths and shifts are provided for temperatures from 20 000 K to 500 000 K and for an electron density of 10(17) cm(-3). Obtained results have been used to study the influence of Stark broadening on spectral lines in DO white dwarf atmospheres and it has been found that exist broad layers where this broadening mechanism is dominant in comparison with thermal Doppler broadening.

International audience; We will consider Stark broadening of non hydrogenic spectral lines in the impact approximation in compact stars: pre-white dwarf and white dwarf atmospheres. In order to show an example, Stark broadening parameters have been calculated, using the impact semiclassical perturbation approach for four Xe VI spectral lines. Obtained results have been used to demonstrate the influence of Stark broadening in DA and DB white dwarf atmospheres.

The electron-impact widths for 15 doubly charged Nb ion lines have been theoretically determined by using the modified semiempirical method. Using the obtained results, we considered the influence of the electron-impact mechanism on line shapes in spectra of chemically peculiar stars and white dwarfs., 10 pages, 2 figures, 1 table, accepted in Advances in Space Research

Stark broadening parameters for 36 multiplets of B IV have been calculated using the semi-classical perturbation formalism. Obtained results have been used to investigate the regularities within spectral series and temperature dependence., 8 pages, 6 figures, 1 table, in press in Advances in Space Research