The Mossbauer spectroscopy and analytical investigations of the polycrystaline compounds with general formula ZnxSnyCr2Se4

We present combined X-ray powder diffraction and Mossbauer 119Sn studies of polycrystalline compounds with a general formula ZnxSnyCrzSe4 (where x + y + z ¼ 3). The obtained single-phase compounds crystallize in the spinel cubic structure | Fd3m. Tin ions are found to occupy both tetrahedral and octahedral sublattices. On the contrary to the strong tetrahedral site preference energy of Sn, the presented data strongly suggest that the increase in lattice parameters with Sn doping is caused by Sn ions that incorporated into octahedral positions. A quadrupole and isomer shifts of 119Sn in (SnSe4)6¡ and (SnSe6)4¡ are also reported

Synthesis of unsymmetrical alkyl acetals via addition of primary alcohols to allyl ethers mediated by ruthenium complexes

Ru-catalyzed synthesis of mixed alkyl–alkyl acetals via addition of primary alcohols to allyl ethers has been extended to include long-chain and/or functionalized substrates. The catalytic systems for these reactions were generated from RuCl2(PPh3)3 and [RuCl2(1,5-COD)]x and phosphines [PPh3 or P(p-chlorophenyl)3] or SbPh3 . Of particular importance is the almost quantitative elimination of transacetalization. The addition proceeds through allyl complexes, not via isomerization of allyl ethers––subsequent addition of ROH to vinyl ethers

Nondestructive analysis of single crystals of selenide spinels by X-ray spectrometry techniques

The paper presents possibilities and difficulties in nondestructive analysis of small multielement single crystals performed by means of X-ray spectrometry techniques: micro-X-ray fluorescence spectrometry (μ-XRF), energydispersive electron probe microanalysis (ED-EPMA), and X-ray photoelectron spectroscopy (XPS). The capability of the X-ray spectroscopy techniques in elemental analysis is demonstrated with the single crystals of selenide spinels of the general formula MxNyCrzSe4 (M+2 and N+3 are, for example, Zn+2, V+3, Ga+3, Cd+2, In+3, and Sb+3). The results of the nondestructive analyses (μ-XRF, ED-EPMA, and XPS) are compared with those obtained by inductively coupled plasma optical emission spectrometry (ICP-OES) and wavelength-dispersive X-ray spectrometry (WDXRF) following sample digestion. The present study shows satisfactory agreement between the results of μ-XRF analysis performed using the standardless fundamental parameter method and the results obtained with the WDXRF and ICP-OES analyses. If the measured single crystal is precisely positioned, the difference between μ- XRF and wet analysis (WDXRF and ICP-OES) does not exceed 5% rel. The reliable results of ED-EPMA can be obtained only if the measured area is sufficiently large, i.e., of 200×300 μm. Even if this condition is fulfilled, the relative difference between the ED-EPMA and the wet analysis may reach 10% rel. In case of the XPS analysis, the accuracy of results depends on the proper preparation of the sample surface. It should be free of contamination that can be obtained by scraping in situ in ultrahigh vacuum. The ion etching, commonly used for cleaning the surface, leads to preferential sputtering; therefore, the reliable results cannot be obtained

Selected ions and major and trace elements as contaminants in coalwaste dump water from the Lower and Upper Silesian Coal Basins (Poland)

Many temporary and permanent reservoirs of water occur on or near coal-waste dumps in the Lower- and Upper Silesian Coal Basins (Poland). Little or nothing is known of the degree to which their water chemistry might reflect (i) reservoir type, i.e., whether permanent or temporary, (ii) level of coal-waste thermal activity, i.e., whether inactive or self-heating or burnt-out or (iii) region, i.e., whether the dumps are in Upper- or Lower Silesia. To provide some answers, concentrations of selected ions (NH4 ?, HCO3 -, F-, Cl-, Br-, NO2-, NO3 -, PO43-,SO4 2-) were determined by ion chromatography and of nineteen elements (Al, B, Ba, Ca, Cd, Cr, Cu, Fe, K, Li, Mg, Mn, Na, P, Pb, S, Si, Sr, Zn) by inductively coupled plasma mass spectrometry (ICP-MS). The data allow a number of the following observations. When permanent reservoirs are considered, there is a clear relationship between concentrations of ions and major and trace elements and dump thermal activity. The highest concentrations occur where the thermal activity is high as inorganic components are transformed into more water-soluble forms. As dump thermal activity shows a regional pattern, it follows also that elemental and ion concentrations in the dump waters show significant regional differences. In temporary reservoirs, concentrations of ions and major and trace elements are much lower and any correlations between components less significant than in the permanent reservoirs; these reservoirs exist for too short a time for any balance between coal wasteand water components to be established

Zawartość metalicznych i niemetalicznych pierwiastków w homogenatach próbek tkankowych pobranych z amputowanych na poziomie uda z powodu miażdżycy kończyn dolnych. Doniesienie wstępne

Background: Metallic and non-metallic elements have influence on the development the changes within structure and function of arteries in different regions of vascular tree. The content of elements into arterial walls varies according to geographical origin of people. Material and methods: Tissue specimens were taken from the six lower limbs amputated on the level of thigh due to atherosclerosis. The mean age was 69 (57 to 84). Tissue specimens were collected from the limbs from the level of amputation, the popliteal fossa and the dorsal artery of foot. After chemical processing of the tissues homogenates determination of the content of elements using atomic emission spectrometry method with inductively coupled plasma (inductively coupled plasma optical emission spectroscopy) was performed. The content of Al, Ba, Ca, Cu, Fe, K, Mg, Mn, P, S, Sr and Zn was determined. Results: As a point of reference mean absolute value occurred from six specimens on the level of thigh was assumed as 100%. Content of non-metallic elements such as Ca, P and S rise towards to periphery of amputated limb reaching few times higher values on the level of dorsal artery of foot. Content of some metallic elements such as: Fe, Zn, K and Sr also rise towards to periphery of extremity. The Cu accumulation was the highest on the level of popliteal fossa, while Mn, Al and Mg concentration was the lowest on this same level and the highest in dorsal artery of foot. Conclusions: The influence of individual elements on development the atherosclerosis especially on necrotic changes requires further investigations. Described problem pose a preliminary report only in order to indicate the issue and to check the method of analysis

Fusicoccin Counteracts the Toxic Effect of Cadmium on the Growth of Maize Coleoptile Segments

The effects of cadmium (Cd; 0.1–1000 μM) and fusicoccin (FC) on growth, Cd2+ content, and membrane potential (Em) in maize coleoptile segments were studied. In addition, the Em changes and accumulation of Cd and calcium (Ca) in coleoptile segments treated with Cd2+ combined with 1 μM FC or 30 mM tetraethylammonium (TEA) chloride (K+-channel blocker) were also determined. In this study, the effects of Ca2+-channel blockers [lanthanum (La) and verapamil (Ver)] on growth and content of Cd2+ and Ca2+ in coleoptile segments were also investigated. It was found that Cd at high concentrations (100 and 1000 μM) significantly inhibited endogenous growth of coleoptile segments and simultaneously measured proton extrusion. FC combined with Cd2+ counteracted the toxic effect of Cd2+ on endogenous growth and significantly decreased Cd2+ content (not the case for Cd2+ at the highest concentration) in coleoptile segments. Addition of Cd to the control medium caused depolarization of Em, the extent of which was dependent on Cd concentration and time of treatment with Cd2+. Hyperpolarization of Em induced by FC was suppressed in the presence of Cd2+ at 1000 μM but not Cd2+ at 100 μM. It was also found that treatment of maize coleoptile segments with 30 mM TEA chloride caused hyperpolarization of Em and decreased Cd2+ content in coleoptile segments, suggesting that, in the same way as for FC, accumulation of Cd2+ was dependent on plasma membrane (PM) hyperpolarization. Similar to FC, TEA chloride also decreased Ca2+ content in coleoptile segments. La and Ver combined with Cd2+ (100 μM) significantly decreased Cd content in maize coleoptile segments, but only La completely abolished the toxic effect of Cd2+ on endogenous growth and growth in the presence of FC. Taken together, these results suggest that the mechanism by which FC counteracts the toxic effect of Cd2+ (except at 1000 μM Cd2+) on the growth of maize coleoptile segments involves both stimulation of PM H+-ATPase activity by FC as well as Cd2+-permeable, voltage-dependent Ca channels, which are blocked by FC and TEA chloride-induced PM hyperpolarization

Heavy metal bioaccumulation and antioxidative responses in Cardaminopsis arenosa and Plantago lanceolata leaves from metalliferous and non-metalliferous sites: a field study

The purpose of this study was to determine the concentrations of heavy metals (cadmium, lead, zinc, copper, iron and manganese) in soil, their bioavailability and bioaccumulation in plants leaves. This study also examined their influences on the antioxidant response of the plants Cardaminopsis arenosa and Plantago lanceolata grown in metal-contaminated and non-contaminated soils. The activities of guaiacol peroxidase and superoxide dismutase and the levels of antioxidants such as glutathione, proline and non-protein thiols were measured. Concentrations of the examined metals were several to thousands of times lower in the potentially bioavailable fraction than in the acid-extracted fraction of the soil. Similar mode of antioxidant responses in plant leaves of metalliferous populations indicates the tolerance of plants towards heavy metals. However POD and GSHt had a particularly strong role in defense reactions, as their increase was the most common reaction to heavy metal contamination.The levels of Zn, Cd and Pb in the leaves of C. arenosa better reflected metal concentrations in the metalliferous and non-metalliferous soil than the determined metal concentrations in P. lanceolata. Bioaccumulated Zn, Cd and Pb concentrations were above or in the ranges mentioned as toxic for plant tissues and therefore the studied plants have potential for use in phytostabilization