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Pharmaceuticals belong to pseudo-persistent pollutants because of constant entry into the environment and hazardous potential for non-target organisms, including plants, in which they can influence biochemical and physiological processes. Detailed analysis of results obtained by microscopic observations using fluorescent dyes (berberine hemisulphate, Fluorol Yellow 088), detection of phytohormone levels (radioimmunoassay, enzyme-linked immune sorbent assay) and thermogravimetric analysis of lignin content proved that the drug naproxen (NPX) can stimulate the formation of root structural barriers. In the primary root of plants treated with 0.5, 1, and 10 mg/L NPX, earlier Casparian strip formation and development of the whole endodermis circle closer to its apex were found after five days of cultivation (by 9-20% as compared to control) and after ten days from 0.1 mg/L NPX (by 8-63%). Suberin lamellae (SL) were deposited in endodermal cells significantly closer to the apex under 10 mg/L NPX by up to 75%. Structural barrier formation under NPX treatment can be influenced indirectly by auxin-supported cell division and differentiation caused by its eight-times higher level under 10 mg/L NPX and directly by stimulated SL deposition induced by abscisic acid (higher from 0.5 mg/L NPX), as proved by the higher proportion of cells with SL in the primary root base (by 8-44%). The earlier modification of endodermis in plant roots can help to limit the drug transfer and maintain the homeostasis of the plant.

This research explores the possibilities and limitations of WD-XRF, applied as a method for quantification of 20 elements in plant material, using spiked cellulose standards for calibration. Three different analytical methods were investigated: 1) standards created from pure spiked cellulose; 2) spiked cellulose mixed with 20% of binder and 3) spiked cellulose applied as a thin layer on an inert carrier. Sensitivity, linearity, limit of detection, limit of quantification, repeatability, intralaboratory reproducibility, and accuracy were determined and compared. The accuracy of the investigated methods was tested by analysis of standard reference materials and comparison with other routinely used analytical techniques (ICP-OES and ICP-MS). The comparison included real plant samples which were collected from the environment characterized by different pollution levels. The accuracy of the semiquantitative standardless method was also considered and compared with other investigated methods. Tested methods can be very precise, with good intralaboratory reproducibility over wide linear range. Supplementary material: [https://cherry.chem.bg.ac.rs/handle/123456789/4615] This is the peer-reviewed version of the article: Orlić, J., Gržetić, I., Goessler, W., Braeuer, S., Čáslavský, J., Pořízka, J.,& Ilijević, K.. (2021). Artificial cellulose standards as calibration standards for wavelength-dispersive X-ray fluorescence analysis of elements in plant samples. in Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms Elsevier., 502, 106-117. [https://doi.org/10.1016/j.nimb.2021.06.012]

Europe’s recent summer droughts have had devastating ecological and economic consequences, but the severity and cause of these extremes remain unclear. Here we present 27,080 annually resolved and absolutely dated measurements of tree-ring stable carbon and oxygen (δ13C and δ18O) isotopes from 21 living and 126 relict oaks (Quercus spp.) used to reconstruct central European summer hydroclimate from 75 bce to 2018 ce. We find that the combined inverse δ13C and δ18O values correlate with the June–August Palmer Drought Severity Index from 1901–2018 at 0.73 (P

The ERK signaling pathway, consisting of core protein kinases Raf, MEK and effector kinases ERK1/2, regulates various biological outcomes such as cell proliferation, differentiation, apoptosis, or cell migration. Signal transduction through the ERK signaling pathway is tightly controlled at all levels of the pathway. However, it is not well understood whether ERK pathway signaling can be modulated by the abundance of ERK pathway core kinases. In this study, we investigated the effects of low-level overexpression of the ERK2 isoform on the phenotype and scattering of cuboidal MDCK epithelial cells growing in discrete multicellular clusters. We show that ERK2 overexpression reduced the vertical size of lateral membranes that contain cell-cell adhesion complexes. Consequently, ERK2 overexpressing cells were unable to develop cuboidal shape, remained flat with increased spread area and intercellular adhesive contacts were present only on the basal side. Interestingly, ERK2 overexpression was not sufficient to increase phosphorylation of multiple downstream targets including transcription factors and induce global changes in gene expression, namely to increase the expression of pro-migratory transcription factor Fra1. However, ERK2 overexpression enhanced HGF/SF-induced cell scattering as these cells scattered more rapidly and to a greater extent than parental cells. Our results suggest that an increase in ERK2 expression primarily reduces cell-cell cohesion and that weakened intercellular adhesion synergizes with upstream signaling in the conversion of the multicellular epithelium into single migrating cells. This mechanism may be clinically relevant as the analysis of clinical data revealed that in one type of cancer, pancreatic adenocarcinoma, ERK2 overexpression correlates with a worse prognosis.

This paper describes the present applied research focused on pyrolysis oil as one of the three products of sewage sludge (SS) thermal treatment processing—microwave assisted pyrolysis (MAP). Specifically, the full-scale MAP unit with 3 kW magnetron and with the frequency of 2.45 GHz at low pressure conditions is in operation at AdMaS Research Centre, Brno University of Technology (AdMaS BUT). The aim of this paper is to present a chemical characterization of obtained pyrolysis oil together with the suitable analytical determination methods. Detailed characterization of pyrolysis oil from SS was realized by precipitation in n-pentane, fractionation of pentane-soluble part by column chromatography on activated silica by stepwise elution and analysis of obtained fractions by comprehensive orthogonal two-dimensional gas chromatography with time-of-flight mass spectrometric detection. Substances from several groups have been identified at the pyrolysis oil from SS sample: alkanes (110 compounds), alkenes and alkynes (184 compounds), cycloalkanes (104 compounds), aromatic and polyaromatic hydrocarbons (646 compounds), further lower numbers of alcohols, aldehydes, esters, carboxylic acids and heterocycles. The paper also presents a comparison of the above mentioned used two chromatographic methods and imply a basic ecotoxicological test—small algal screening.

This paper presents for the first time the determination of monensin monosodium salt (MnzNa) by means of square wave voltammetry (SWV), cyclic voltammetry (CV), and, in parallel, direct infusion electrospray ionization tandem mass spectrometry (DI–ESI–MS/MS). The influence of various factors, such as pH, buffer composition, and SWV parameters on current response was studied. The best SWV signal was obtained at about −1.50 V versus an Ag/AgCl/KCl reference electrode in Britton–Robinson (B–R) buffer. Under optimal conditions, the SWV response of the renewable silver amalgam film electrode Hg(Ag)FE was linear over two MnzNa concentration ranges, from 7.5 × 10−8 to 5.0 × 10−7 mol L−1 and from 5.0 × 10−7 to 1.0 × 10−5 mol L−1. The limits of detection and quantification were 1.27 × 10−8 mol L−1 and 4.23 × 10−8 mol L−1, respectively. The applicability of the developed SWV method was investigated in the determination of MnzNa in horse feed by the standard addition method. CV was applied to understand the electrode mechanism of MnzNa. Finally, direct infusion electrospray ionization tandem mass spectrometry (DI–ESI–MS/MS) was used to determine MnzNa in horse feed samples by the external calibration method. The detector response was linear in the concentration range of 1.1 × 10−7 to 1.4 × 10−6 mol L−1. The obtained limits of detection and quantification were 3.4 × 10−8 mol L−1 and 1.1 × 10−7 mol L−1, respectively. Statistical analysis of MnzNa determination results from SWV and DI–ESI–MS/MS did not reveal any significant differences between them.

A detailed investigation into the viscosity, density, and refractive index of a binary mixture of propane-1,3-diol/water was performed for the whole range of mass fractions of propane-1,3-diol. The viscosity and density were measured over a wide range of temperatures from T = 253.15 K to T = 353.15 K where possible, or to the nearest safe point before freezing. The refractive indices were measured for the same dilutions as in the case of the viscosity and density over a reduced temperature range of T = (278.15 to 318.15) K. A mathematical analysis via excess properties was conducted and fitted to the Redlich–Kister equation. Furthermore, a prediction of density data is provided by a polynomial and DIPPR exponential model. The viscosity data are fitted to Grunberg-Nissan, Lederer, McAllister, and Heric models and a new combined model with variable temperature and molar and mass fractions based on these models is presented. Data comparison of the propane-1,3-diol/water binary mixture is performed on propan-...

Alkaloids known as secondary metabolites are grouped by typical structural characteristics into large families such as pyrrolizidine alkaloids (PAs) comprising more than 350 individual heterocyclic compounds. The PAs present a serious health risk to human and livestock; hence there is a need for methods that allow these dangerous plant toxins to be determined. In this study, a fast, reliable and sensitive approach is proposed to identify and quantify PAs in feed samples. PAs including monocrotaline, senkirkine, senecionine, seneciphylline and retrorsine were determined by ultra-performance liquid chromatography coupled with tandem mass spectrometry. Sample preparation was based on a modified QuEChERS approach. The mean recovery, precision, matrix effects and limits of quantification were assessed for three matrices within the method validation. The presented method was used to inspect 41 various feed samples, where the presence of PAs was expected. Roughages and feed for rabbits contained the highest levels of PAs, in general.

In this study, an analytical method for the determination of 17 mycotoxins was developed and validated: common (aflatoxins B1, B2, G1, and G2, fumonisins B1 and B2, ochratoxin A, deoxynivalenol, nivalenol, zearalenone, T-2 and HT-2 toxin) and “emerging” toxins (enniatins A, A1, B, and B1, and beauvericin) were detected using ultra-performance liquid chromatography coupled to mass spectrometry. A modified QuEChERS method was used for extraction. The method was applied to a total set of 52 barley and malt samples. All samples were contaminated with at least one of mycotoxins. None of the investigated samples contained any of four aflatoxins nor ochratoxin A. Fumonisin B1 occurred only in one sample, Fumonisin B2 and zearalenone were found in two barley samples. Enniatins were detected in all samples. The values did not exceed the maximum allowable limit for the selected mycotoxins in unprocessed or processed cereals set by the European Union.

The solvent extraction process is regarded amongst other known methods to be applicable for decontamination of sensitive equipment components, especially in cases the components are contaminated in-depth with chemical warfare agents. Viability of the solvent extraction method was evaluated on coupons of butadiene rubber contaminated by sulphur mustard before decontamination by the solvent extraction. The contaminated coupons were extracted in a flow cell, which the solvent (ethoxynonafluorobutane) passed through. Three following specific operational factors, namely the temperature, the flow rate, and the power of ultrasound bath, were assessed for the extent of influencing upon the respective observed extraction efficiencies. The paper describes the results of the evaluation of the solvent extraction effectiveness. Defence Science Journal, 2014, 64(2), pp. 168-172. DOI: http://dx.doi.org/10.14429/dsj.64.3887

In 2008–2011, the occurrence of deoxynivalenol (DON), zearalenone (ZON), T-2 toxin (T-2), and HT-2 toxin (HT-2) was studied in 325 malting barley samples collected from various regions of the Czech Republic. The highest occurrence of fusarium mycotoxins was recorded in crop 2009 (2213.5, 59.4 and 145.0 μg/kg for DON, ZON and ∑T-2, HT-2, respectively). Only one measured value exceeded the maximum allowable limit for DON set by the European Union. The validated method of high-performance liquid chromatography coupled with mass spectrometry was used for the analysis of the above mentioned toxins. Limits of detection were 1.5 μg/kg for DON, ZON and HT-2 and 0.3 μg/kg for T-2, the limits of quantification were 5.0 μg/kg for DON, ZON and HT-2 and 1.0 μg/kg for T-2.

This study is focussed on a comprehensive investigation on the state of pollution of Danube and Sava rivers in Belgrade region. Different complementary analytical approaches have been used covering both (i) organic ccontaminants in river water by target analyses of hormones and neonicotinoids as well as non-target screening analyses and (ii) heavy metals in sediments. Finally, some common water quality parameters have been analysed. The overall state of pollution is on a moderate level. Bulk parameters did not reveal any unusual observation. Also quantification of preselected organic contaminants did not point to elevated pollution. A more significant contamination was measured for chromium, nickel, zinc and partially copper in sediments with values above target values according to Serbian regulations. Lastly, non-target screening analysis revealed a wider spectrum of organic contaminants comprising pharmaceuticals, technical additives, personal care products and pesticides. The study presented a comprehensive view on the state of pollution of Sava and Danube rivers and is the base for setting up further monitoring programs. As a superior outcome it has been illustrated how different chemical analyses can point to different assessments of the river quality. The comparison of target and non-target analyses pointed to potential misinterpretation of the real state of pollution.

The ERK (extracellular signal-regulated kinases) cascade has an evolutionarily conserved three tier architecture consisting of protein kinases Raf, MEK (MAPK/ERK kinase) and ERK. Following activation, ERK phosphorylates various cellular elements leading to diverse cellular responses. Downstream of ERK the family of p90 ribosomal S6 kinases (RSKs) has been proven to be an important conveyor of ERK signaling, however, little is known if ERK and RSK coordinate their functions to generate a specific biological response. Here we show that in epithelial cells conditional activation of the ERK pathway causes phenotypic conversion of epithelial cells to autonomously migrating cells. This process involves two sequential steps characterized by loss of apical–basal polarity followed by cell scattering. The activation of ERK, but not RSK, is sufficient for the execution of the first step and it requires calpain mediated remodeling of actin cytoskeleton. Conversely, RSK regulates the successive stage characterized by cell–cell contact weakening and increased cellular migration. Thus, ERK and RSK regulate different cellular subprograms and coordinated execution of these subprograms in time generates a relevant biological response. Our data also suggest that the mechanism by which the ERK pathway controls a cellular response may be distributed between ERK and RSK, rather than being elicited by a single effector kinase.

This study assessed the state of waters in Belgrade regarding pollution with musk compounds as the target contaminants. Eleven of these compounds were alicyclic, two were macrocyclic, and one was polycyclic. Solid-phase microextraction was used for the isolation of these compounds from waste, surface and underground waters and from processed water prepared for drinking, while comprehensive orthogonal two-dimensional gas chromatography with mass spectrometry was used as the final analytical method. In wastewater samples, galaxolide was detected in concentrations of 1.13 and 0.40 mu g/L, while in the Sava River and underground water its concentrations were 0.09 and 0.038 mu g/L. The lowest concentrations of the investigated musk compounds were detected in underground water samples, indicating that this is the cleanest water of all the analyzed sources with respect to musk compounds. Comparing the results of musk compound concentrations determined in surface river water samples and clean river water samples utilized for drinking, a lower concentration of these compounds was detected in the clean river water samples. The majority of musk compounds were found in waters utilized for drinking. Based on the concentration values, we conclude that the analyzed waters are moderately polluted with these compounds.

Water solutions of organic dye Direct Red 79 were treated by DC high voltage created by diaphragm discharge (input power up to 160 W). Higher dye decoloration (60% after 40 min) was observed in the anode part of the reactor by UV–VIS spectroscopy. Recorded absorption spectra showed shifts of absorption maximum to lower wavelength values that were related to the formation of stable degradation products. Absorption spectra obtained in the cathode part of the diaphragm reactor produced only negligible shifts of absorption maximum and the dye decomposition rate reached 25% after 80 min of the treatment. HPLC-MS method revealed five main compounds in the anode part and another three ones in the cathode part. Analysis of identified products showed on the initial decomposition of one azo-group in the original dye molecule. Significant changes of solution properties during the diaphragm discharge were observed, too. Solution conductivity increased in both parts of the reactor. Solution pH dropped from the initial neutral value to acidic conditions (up to 3) in the anode part and to alkaline conditions (up to 10) in the cathode part. Changes were induced by formation of reactive species by the discharge and by electrochemical reactions on electrodes.

The determination of polychlorinated biphenyls (PCBs) in water, sediment and fish samples from the Czech Republic was carried out using high resolution gas chromatography with electron capture detection. PCBs concentrations in water and sediment samples were rather low and corresponded with the findings from some prior studies. On the other hand, investigated samples of fish tissue were highly contaminated (on average 1.3-266 ng/g fat for individual PCBs), thus, a continuing contamination of fish species with PCBs was proved.

The spreading of adhering cells is a morphogenetic process during which cells break spherical or radial symmetry and adopt migratory polarity with spatially segregated protruding cell front and non-protruding cell rear. The organization and regulation of these symmetry-breaking events, which are both complex and stochastic, are not fully understood. Here we show that in radially spreading cells, symmetry breaking commences with the development of discrete non-protruding regions characterized by large but sparse focal adhesions and long peripheral actin bundles. Establishment of this non-protruding static region specifies the distally oriented protruding cell front and thus determines the polarity axis and the direction of cell migration. The development of non-protruding regions requires ERK2 and the ERK pathway scaffold protein RACK1. RACK1 promotes adhesion-mediated activation of ERK2 that in turn inhibits p190A-RhoGAP signaling by reducing the peripheral localization of p190A-RhoGAP. We propose that sustained ERK signaling at the prospective cell rear induces p190A-RhoGAP depletion from the cell periphery resulting in peripheral actin bundles and cell rear formation. Since cell adhesion activates both ERK and p190A-RhoGAP signaling this constitutes a spatially confined incoherent feed-forward signaling circuit.

A library of negative ion electrospray ionization mass spectra and tandem mass spectra (MS/MS) of sulfonated dyes has been developed for fast identification purposes. The uniform protocol has been elaborated and applied to the measurements of more than 50 anionic dyes. Three collision energies are selected in our protocol which ensures that at least one of them provides a suitable ratio of product ions to the precursor ion. The robustness is investigated with altered values of tuning parameters (e.g. the pressure of the nebulizing gas, the temperature and the flow rate of drying gas, and the mobile phase composition). The results of the inter-laboratory comparison of product ion mass spectra recorded on seven different tandem mass spectrometers (three ion traps, two triple quadrupoles and two hybrid quadrupole time of flight instruments) are presented for four representative anionic dyes--azo dye Acid Red 118, anthraquinone dye Acid Violet 43, triphenylmethane dye Acid Blue 1 and Al(III) metal-complex azo dye. The fragmentation patterns are almost identical for all tandem mass analyzers, only the ratios of product ions differ somewhat which confirms the possibility of spectra transfer among different mass analyzers with the goal of library formation.

Calix[4]arene derivatives bearing two residues A(–) derived from cobalt bis(dicarbollide)(1–) (1) and two CMPO groups B at their narrow rim were synthesized from tBu-calix[4]arene in four steps. The first step involved the preparation of tBu-calix[4]arene diether derivatives with appropriate precursors for amino groups (mostly nitriles 3). These were O-alkylated through ring-opening reactions with the zwitterionic dioxane derivative [(8-O(CH2CH2)2O-1,2-C2B9H10)-(1′,2′-C2B9H11)-3,3′-Co]0 (10) to produce ionic nitrile derivatives 4. Reduction of the nitrile groups with BH3·SMe2 (or deprotection in the case of the corresponding phthalimido or Boc derivatives 8) led to a series of diamines 5a–f, which were subsequently converted into the corresponding CMPO derivatives 6a–f by acylation with p-nitrophenyl(diphenylphosphoryl) acetate. Pure cone conformers were isolated in moderate to excellent yields after the second or third reaction step, although the presence of other conformers in the reaction mixtures was sometimes observed by NMR spectroscopy and HPLC, and in one case a di-A(–)-di-B derivative 6c* in the 1,3-alternate conformation was prepared. The novel ionic ligands 6a–f showed dramatically enhanced extraction abilities for trivalent actinides and lanthanides in relation to the previously reported simple covalent combination of one A(–) with one B group or to various synergistic mixtures of calixarenes substituted exclusively with two A(–) or two B moieties. A 1:1 mixture of calix[4]arenes containing four A(–) anions (13) and four CMPO functions (14), however, showed similarly high extraction efficiency, comparable to that of the best calixarenes 6b–d with mixed substitution. Complexation studies with 6c for La3+, Eu3+ and Yb3+ in methanol carried out by UV spectrophotometry and microcalorimetry revealed the formation of 1:1 and 1:2 metal-to-ligand complexes with log β values ranging from 9.6 to 11.7.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)

The synthesis of a new, paramagnetic closo-[(8-(-CH2CH2O)2-1,2-C2B9H10)(1′,2′-C2B9H11)-3,3′-Fe]0 (3) is reported. This compound can serve as a versatile building block for construction of both anionic and zwitterionic derivatives, as exemplified by the synthesis of a series of compounds of general formula closo-[(8-X-(CH2CH2O)2-1,2-C2B9H10)(1′,2′-C2B9H11)-3,3′-Fe], bearing organic end groups (X = NC5H5 (4), (C6H5)3P (5), OH (6), and 2-O(1-CH3O–C6H4) (7)) attached to the cluster by a diethyleneglycol spacer. Molecular structures of 3, 4, 5 and 7 were determined by single-crystal X-ray diffraction analysis and by the long-time neglected method of paramagnetic, high field NMR (1H, 13C and 11B) spectroscopy.

Single- and multibranched centrosymmetric derivatives incorporating B12 clusters [B12H11-N(H)=C(H)-C6H4-C6H4-C(H)=(H)N-B12H11]2- (3) and [1,3,5-(4-(B12H11-N(H)=C(H))-C6H4)-C6H3]3- (5) have been synthesized. Both derivatives were characterized by multinuclear NMR and ESI-MS analyses. To the best of our knowledge, compound 5 is the first example of a multicage derivative bearing three B12 units. Compounds 3 and 5 are only slightly yellowish colored. The UV-vis absorption curves of 3 and 5 show intense absorption bands at 360 and 314 nm, respectively. This result permits us to confirm the strong donor effect of the B12 cluster. The hypsochrome effect observed for compound 5 compared to that of compound 3 confirms the interest in multibranched derivatives for the preparation of two-photon absorption materials active in the visible range.

Semipermeable membrane devices (SPMDs) are nowadays used as passive samplers of organic pollutants. The knowledge of the sampling rate values (R S) of each substance trapped on membranes is necessary to calculate their average concentration. Here we calculate R S values for 16 polycyclic aromatic hydrocarbons using the comparison of active sampling method results and the amounts sequestered by SPMDs at varying exposure times.

Polycyclic aromatic hydrocarbons (PAHs) with molecular weight exceeding 278 amu were analyzed in air, water, and soils from the area and vicinity of the DEZA Chemical Plant (Vala w ske Mezi q i ) i, Czech Republic). Air and water were sampled using semipermeable membrane devices (SPMDs); grab sampling was applied for soils. Laser desorption/ionization-time-of-flight mass spectrometry (LDI-TOF MS) and liquid chromatography/ion trap mass spectrometry with atmospheric pressure chemical ionization (LC/APCI-ITMS) were employed for the quick assessment of PAH distribution and for the identification and quantification of some high-molecular-weight PAHs. Compounds with molecular mass up to 450 u were found. LDI-TOF mass spectra and selected LC/APCI-ITMS profiles (m/z 303, m/z 327, and m/z 351) were compared to identify potential source of contamination in this locality. High-molecular-weight PAHs were found in all environmental compartments in the area studied; their levels were quite high close to their source a...

A series of crown ether derivatives of the cobalta bis(dicarbollide) closo-[(1,2-C2B9H11)2-3,3′-Co]− (1) anion was prepared using two synthetic strategies. The first method employs dioxane ring cleavage of the closo-[{8-(C4H8O2)-1,2-C2B9H10}-3,3′-Co-(1′,2′-C2B9H11)]0 zwitterionic species with sodium oxymethyl crowns, producing a series of anions with spacer bonded crown ether moieties varying in crown ether ring size. Three compounds of this group; closo-[{8-(15-crown-5-CH2O)-(CH2CH2O)2-1,2-C2B9H10}-3,3′-Co-(1′,2′-C2B9H11)]− (2), closo-[{8-(18-crown-6-CH2O)-(CH2CH2O)2-1,2-C2B9H10}-3,3′-Co-(1′,2′-C2B9H11)]− (3) and [{8-(21-crown-7-CH2O)-(CH2CH2O)2-1,2-C2B9H10}-3,3′-Co-(1′,2′-C2B9H11)]− (4) were prepared in high yields. The second approach involved reaction of deprotonated closo-[8,8′-(OH-1,2-C2B9H12)2-3,3′-Co]− with p-toluenesulfonyl esters derived from hydroxymethyl crown ethers. Only compounds bearing one crown ether ring resulted in preparative amount from this reaction, the [(8-{(15-crown-5-CH2O)-1,2-C2B9H10}-3,3′-Co-{8′-(HO)-1′,2′-C2B9H10}]− (5) and [{8-(21-crown-7-CH2O)-1,2-C2B9H10}-3,3′-Co-(8′-HO-1′,2′-C2B9H10)]− (6). All compounds were characterized by high field 1H and 11B NMR methods, HPLC and MS, with electrospray ionization, and the molecular structure of the Cs+ complex of species 5 was determined by single crystal X-ray diffraction analysis. These compounds represent the first examples where oxygen crown ethers were successfully bonded to the cage of anion 1. The scope and limitations of the use of these compounds in the liquid–liquid extraction of Cs+ and Sr2+ from nuclear waste were studied, including comparison of extraction efficiency and selectivity of the covalently bonded species under study with synergistic mixtures of hexabrominated anion 1 with crown ethers. As a rule, crown ethers linked to the cobalta bis(dicarbollide) cage display distribution coefficients for Cs+ and Sr2+ comparable to the crown ethers mixed with the hexabromoderivative of 1, however, they were found to exhibit better selectivity with respect to Na+ cation.

Synthesis of two new B(12) substituted derivatives of the closo-[1-CB11H12]- anion (1) is reported. The zwitterionic derivative containing dioxane ring {12-[O(CH2CH2)2O]+-1-CB11H11-}0 (2) was obtained in moderate yield using reaction of anion 1 with dioxane as solvent, induced by dimethyl sulfate. The anion [12-(HO)-1-CB11H11]- (3) was obtained in high yield upon treatment of the parent anion with 80% H2SO4 at high temperature. Both compounds containing reactive functionalities were designed to serve as useful synthons for a variety of synthetic purposes. The compounds were characterized by 11B and 1H high-field NMR, IR spectroscopy, mass spectrometry, melting points and TLC. Molecular structure of compound 2 was determined by single crystal X-ray diffraction analysis.

In spite of the published claims to the contrary, Paracoccus denitrificans was shown to contain a heme derivative, virtually indistinguishable from the Escherichia coli heme O on the basis of the reverse-phase high-performance liquid chromatography and MALDI-TOF mass spectrometry analyses. Aeration of the anoxically grown culture resulted in the disappearance of a significant portion of this compound with concomitant build-up of heme A.

An overview of sources of PAHs in the Czech Republic and that of the values of emission factors and annual emissions are given. Residential heating, coal fired stations, and production of PAHs, carbon black, and coke were identified as the major sources of PAHs in Czech Republic. The total annual emission of 16 PAHs suggested by US EPA was assessed at 700 to 735 tons per annum.

In order to achieve sustainable development, environmental protection shall constitute an integral part of the development process and cannot be considered in isolation from it [1]. The environment, especially water ecosystem, is continuously loaded with foreign organic chemicals (xenobiotics) released by urban communities and industries. Water is not a com‐ mercial product like any other but, rather, a heritage which must be protected, defended and treated as such [2]. In the 20th century, many organic compounds, such as polychlorinat‐ ed biphenyls (PCBs), organochlorine pesticides (OCPs), polycyclic aromatic hydrocarbons (PAHs), polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) have been produced and, in part, released into the environment [3]. The ultimate sink for many of these contaminants is the aquatic environment, either due to direct discharges or to hydro‐ logic and atmospheric processes [4]. In the 21st century „new“ pollutants namely pharma‐ ceuticals, cosmetics and endocrine disrupting chemicals (EDCs) have become a source of concern. Collectively, they are referred to as PPCPs (Pharmaceuticals and Personal Care Products) and are now viewed as emerging contaminants. A wide range of pharmaceutical and personal care products (PPCPs) is available on the market. From this range various classes, e.g., antibiotics, antiphlogistics, antiepileptics, beta-blockers, lipid regulators, vaso‐ dilators, and sympathomimetics, have been detected in drinking water, groundwater, wastewater, sewage, and manure [5]. In last time there is increasing evidence that some of these compounds are persistent in the environment, impacting nontarget organisms in vari‐ ous ways including changes in sex ratios of higher organisms [6,7]. The presence of a xeno‐

The six high‐mountain soil samples (more than 1,100 m above sea level) from National Park Krkonose (North Bohemia, Czech‐Polish border) were analyzed for contents of PCBs, non‐ortho and mono‐ortho PCBs and PCDDs/Fs. The content of PCBs ranged between 31 and 137 ng.g‐1 dry soil. PCB 77 was predominant coplanar PCBs. The contents of PCDDs/Fs ranged between 17 and 29 pg.g‐1 1‐TEQ of PCDDs/Fs and were between 20.1 and 41.2 pg.g‐1 T‐TEQ of PCDDs/Fs and coplanar PCBs. The contents of PCDFs were significantly higher than those of PCDDs. The predominant congeners were OCDF and OCDD. The contribution of non‐ortho and mono‐ortho PCBs to the total 1‐TEQ ranged between 9.3 and 49.3%.

The possible negative effluents of model source of PAHs on the environment were observed. The model source of PAHs was Urx Chemical Factory, Valasske Mezifici, Czechoslovakia, who produced aromatic compounds from benzene to phenanthrene and some of their derivatives and carbon black.

The samples of soils, earthworms and vegetation (needles, lichens, mosses) were collected for the realization of Project TOCOEN (Toxic Organic Compounds in the ENvironment). The samples were collected from three TOCOEN model areas in Czechoslovakia—one city and two rural areas. The samples were analyzed for polycyclic aromatic hydrocarbons (PAHs), chlorinated pesticides (C1‐PEST) and polychlorinated biphenyls (PCBs).

Project TOCOEN (Toxic Organic COmpounds in the ENvironment) is a new nontraditional research project of the Department of Environmental Studies, Purkyne University, Brno, Czechoslovakia and many other Czechoslovak research institutes and factories. The aim of this Project is understanding the fate of selected organic pollutants (PAHs, chlorinated pesticides, PCBs, PCDDs, PCDFs) in all parts of the environment, and modelling the fate of these compounds in the environment.

Surface waters and bottom sediments were sampled for realization of Project TOCOEN (Toxic Organic Compounds in the ENvironment). The samples were collected from three TOCOEN model areas in Czechoslovakia—one city and two rural areas. The samples were analyzed for polycyclic aromatic hydrocarbons (PAHs), chlorinated pesticides (Cl‐PEST) and polychlorinated biphenyls (PCBs).

Different sample preparation methods for the determination of polycyclic aromatic hydrocarbons (PAHs) in lake and river sediments were compared and evaluated. Freeze‐dried sediment materials were e...

Pressurised fluid extraction using water or methanol was employed for the extraction of stevioside from Stevia rebaudiana Bertoni. The extraction method was optimised in terms of temperature and duration of the static or the dynamic step. Extracts were analysed by liquid chromatography followed by UV and mass-spectrometric (MS) detections. Thermal degradation of stevioside was the same in both solvents within the range 70-160 degrees C. Methanol showed better extraction ability for isolation of stevioside from Stevia rebaudiana leaves than water within the range 110-160 degrees C. However, water represents the green alternative to methanol. The limit of detection of stevioside in the extract analysed was 30 ng for UV detection and 2 ng for MS detection.

The covalent attachment of two CMPO-functions and two anionic Cosan groups to the narrow rim of tert-butylcalix[4]arene leads to a dramatic increase of the extraction efficiency for the cone isomer; Am(3+) is removed from 5 x 10(-8) M solution to more than 99% by a single extraction step with a 3 x 10(-6) M solution of the calixarene.

Non-centrosymmetric pi-conjugated systems incorporating closo-dodecaborate clusters, [NC-C6H4-C(H=N(H)-B12H11]-(2), [NC-C6H4-C(H)=C(H)-C(6)H(4)-C(H)=N(H)-B12H11]-(3), and [NC-C6H4-C(H)=C(H)-C6H4-C(H)=C(H)-C6H4-C(H)=N(H)-B12H11]-(4) have been synthesized by reaction of the monoamino derivative of B12, [B12H11NH3]-(1), with various arylaldehydes, R-C6H4-CHO. These Schiff base-like compounds were fully characterized by multinuclear NMR spectroscopy and mass spectrometry. In order to evaluate these boron rich pi-systems as potential materials for two-photon absorption (TPA) processes, UV linear absorption curves were recorded for 3 and 4, and comparatively studied with those of the boron-free pi-systems NC-C6H4-C(H)=N-CH3(5) and NC-C6H4-C(H)=C(H)-C6H4-C(H)=N-CH3(6). The donor effect of the boron cluster was evidenced by a shift to the lower energy of the absorption band in the spectra of systems incorporating B12. The two photon absorption (TPA) spectrum of compound , obtained by the up-conversion method, shows a resonance at 720 nm with a cross-section sigma(TPA) of 35 x 10(-50) cm(4) s photon(-1) molecule(-1). This value suggests the potential of B12 clusters to be used as new donor groups for the synthesis of non-linear materials.

Laser desorption-ionisation/time-of-flight mass spectrometry (LDI/TOF MS) and liquid chromatography/atmospheric pressure chemical ionisation-ion trap mass spectrometry (HPLC/APCI-ITMS) were used for the analysis of polycyclic aromatic hydrocarbons with molecular weight exceeding 278 Da (HMW-PAHs) in air, water and soil samples from the contaminated area of DEZA chemical plant, Valasske Mezřici, Czech Republic, and from its vicinity. Semipermeable membrane devices (SPMDs) were employed for passive sampling. LDI-TOF MS proved to be a suitable method for quick evaluation of the HMW-PAHs distribution; the presence of PAHs with molecular mass exceeding 500 Da in real samples was proved by this method. Identification and quantitation of individual PAHs was realised using LC/APCI-ITMS. LDI-TOF mass spectra and selected LC/APCI-MS profiles (m/z 303, 327 and 351) were used to confirm the source of contamination by high-molecular-weight PAHs in this area.

Polycyclic aromatic hydrocarbons (PAHs) were analysed in mosses (Hypnum cupressiforme) and pine needles (Pinus sylvestris) collected in the Czech Republic between 1988-94 at a regional background site in Kosetice, south Bohemia (1988-94) and two industrial sources. One industrial site (sampled 1989-91) in middle Moravia, was near a factory producing PAHs, carbon black and phthalates, the other (sampled 1991-93) near a coal and gas fuel production plant in western Bohemia. Selected chlorinated pesticides and polychlorinated biphenyl congeners were also analysed in samples at the regional background site. This study clearly shows that vegetation sampling can be used to show spatial differences in the atmospheric burden of a range of persistent organic pollutants with differences in the mixtures of compounds reflecting differences in their regional or local use/atmospheric emission.

SPMDs (Semipermeable Membrane Devices) were utilised for the monitoring of PAHs in the area of the DEZA chemical plant and in its vicinity. The devices were deployed in air, water, and soils. The passive samplers were successfully used in some places inside the factory where active air sampling methods could not be used due to safety or space reasons.