Complexation of lanthanides, actinides and transition metal cations with a 6-(1,2,4-triazin-3-yl)-2,2′:6′,2′′-terpyridine ligand: implications for actinide(III)/lanthanide(III) partitioning

The quadridentate N-heterocyclic ligand 6-(5,5,8,8-tetramethyl-5,6,7,8-tetrahydro-1,2,4-benzotriazin- 3-yl)-2,2′ : 6′,2′′-terpyridine (CyMe4-hemi-BTBP) has been synthesized and its interactions with Am(III),U(VI), Ln(III) and some transition metal cations have been evaluated by X-ray crystallographic analysis, Am(III)/Eu(III) solvent extraction experiments, UVabsorption spectrophotometry, NMR studies and ESI-MS. Structures of 1 : 1 complexes with Eu(III), Ce(III) and the linear uranyl (UO2 2+) ion were obtained by X-ray crystallographic analysis, and they showed similar coordination behavior to related BTBP complexes. In methanol, the stability constants of the Ln(III) complexes are slightly lower than those of the analogous quadridentate bis-triazine BTBP ligands, while the stability constant for the Yb(III)complex is higher. 1H NMR titrations and ESI-MS with lanthanide nitrates showed that the ligand forms only 1 : 1 complexes with Eu(III), Ce(III) and Yb(III), while both 1 : 1 and 1 : 2 complexes were formed with La(III) and Y(III) in acetonitrile. A mixture of isomeric chiral 2 : 2 helical complexes was formed with Cu(I), with a slight preference (1.4 : 1) for a single directional isomer. In contrast, a 1 : 1 complex was observed with the larger Ag(I) ion. The ligand was unable to extract Am(III) or Eu(III) from nitric acid solutions into 1-octanol, except in the presence of a synergist at low acidity. The results show that the presence of two outer 1,2,4-triazine rings is required for the efficient extraction and separation of An(III)from Ln(III) by quadridentate N-donor ligands.

Desert dust deposition on Mt. Elbrus, Caucasus Mountains, Russia in 2009-2012 as recorded in snow and shallow ice core: high-resolution "provenancing", transport patterns, physical properties and soluble ionic composition

A record of dust deposition events between 2009 and 2012 on Mt. Elbrus, Caucasus Mountains derived from a snow pit and a shallow ice core is presented for the first time for this region. A combination of isotopic analysis, SEVIRI red-green-blue composite imagery, MODIS atmospheric optical depth fields derived using the Deep Blue algorithm, air mass trajectories derived using the HYSPLIT model and analysis of meteorological data enabled identification of dust source regions with high temporal (hours) and spatial (cf. 20–100 km) resolution. Seventeen dust deposition events were detected; fourteen occurred in March–June, one in February and two in October. Four events originated in the Sahara, predominantly in north-eastern Libya and eastern Algeria. Thirteen events originated in the Middle East, in the Syrian Desert and northern Mesopotamia, from a mixture of natural and anthropogenic sources. Dust transportation from Sahara was associated with vigorous Saharan depressions, strong surface winds in the source region and mid-tropospheric south-westerly flow with daily winds speeds of 20–30 m s−1 at 700 hPa level and, although these events were less frequent, they resulted in higher dust concentrations in snow. Dust transportation from the Middle East was associated with weaker depressions forming over the source region, high pressure centered over or extending towards the Caspian Sea and a weaker southerly or south-easterly flow towards the Caucasus Mountains with daily wind speeds of 12–18 m s−1 at 700 hPa level. Higher concentrations of nitrates and ammonium characterise dust from the Middle East deposited on Mt. Elbrus in 2009 indicating contribution of anthropogenic sources. The modal values of particle size distributions ranged between 1.98 μm and 4.16 μm. Most samples were characterised by modal values of 2.0–2.8 μm with an average of 2.6 μm and there was no significant difference between dust from the Sahara and the Middle East.

High-resolution provenance of desert dust deposited on Mt. Elbrus, Caucasus in 2009–2012 using snow pit and firn core records

The first record of dust deposition events on Mt. Elbrus, Caucasus Mountains derived from a snow pit and a shallow firn core is presented for the 2009–2012 period. A combination of isotopic analysis, SEVIRI red-greenblue composite imagery, MODIS atmospheric optical depth fields derived using the Deep Blue algorithm, air mass trajectories derived using the HYSPLIT model and analyses of meteorological data enabled identification of dust source regions with high temporal (hours) and spatial (ca. 20–100 km) resolution. Seventeen dust deposition events were detected; fourteen occurred in March–June, one in February and two in October. Four events originated in the Sahara, predominantly in northeastern Libya and eastern Algeria. Thirteen events originated in the Middle East, in the Syrian Desert and northern Mesopotamia, from a mixture of natural and anthropogenic sources. Dust transportation from Sahara was associated with vigorous Saharan depressions, strong surface winds in the source region and mid-tropospheric southwesterly flow with daily winds speeds of 20–30 m s−1 at 700 hPa level. Although these events were less frequent than those originating in the Middle East, they resulted in higher dust concentrations in snow. Dust transportation from the Middle East was associated with weaker depressions forming over the source region, high pressure centred over or extending towards the Caspian Sea and a weaker southerly or southeasterly flow towards the Caucasus Mountains with daily wind speeds of 12–18 m s−1 at 700 hPa level. Higher concentrations of nitrates and ammonium characterised dust from the Middle East deposited on Mt. Elbrus in 2009 indicating contribution of anthropogenic sources. The modal values of particle size distributions ranged between 1.98 µm and 4.16 µm. Most samples were characterised by modal values of 2.0– 2.8 µm with an average of 2.6 µm and there was no signifi- cant difference between dust from the Sahara and the Middle East.

Atmospheric electric fields during the Carrington flare

Karen Aplin and Giles Harrison examine international records of the 1859 Carrington flare and consider what they mean for our understanding of space weather today. Space weather is increasingly recognized as a hazard to modern societies, and one way to assess the extent of its possible impact is through analysis of historic space weather events. One such event was the massive solar storm of late August and early September 1859. This is now widely known as the “Carrington flare” or “Carrington event” after the visual solar emissions on 1 September first reported by the Victorian astronomer Richard Carrington from his observatory in Redhill, Surrey (Carrington 1859). The related aurorae and subsequent effects on telegraph networks are well documented (e.g. Clark 2007, Boteler 2006), but use of modern techniques, such as analysis of nitrates produced by solar protons in ice cores to retrospectively assess the nature of the solar flare, has proved problematic (Wolff et al. 2012). This means that there is still very little quantitative information about the flare beyond magnetic observations (e.g. Viljanen et al. 2014).

The effect of alkyl substitution on the extraction properties of BTPhen ligands for the partitioning of trivalent minor actinides and lanthanides in spent nuclear fuels

Bis-triazinylphenanthroline ligands (BTPhens), which contain additional alkyl (n-butyl and sec-butyl) groups attached to the triazine rings, have been synthesized, and the effects of this alkyl substitution on their extraction properties with Ln(III) and An(III) cations in simulated nuclear waste solutions have been studied. The speciation of n-butyl-substituted ligand (C4- BTPhen) with some trivalent lanthanide nitrates was elucidated by 1 H-NMR spectroscopic titrations. These experiments have shown that the dominant species in solution were the 1:2 complexes [Ln(III)(BTPhen)2], even at higher Ln(III) concentrations, and the relative stability of 2:1 to 1:1 BTPhen-Ln(III) complexes varied with different lanthanides. As expected, sec-butylsubstituted ligand (sec-C4 BTPhen) showed higher solubility than C4-BTPhen in certain diluents. A greater separation factor (SFAm/Eu = ca. 210) was observed for sec-C4-BTPhen compared to C4-BTPhen (SFAm/Eu = ca. 125) in 1-octanol at 4 M HNO3 solutions. The greater separation factor may be due to the higher solubility of the 2:1 complex for sec-C4-BTPhen at the interface than the 1:1 complex of C4-BTPhen.

Ni-Zn-Sm nanopowder ferrites: Morphological aspects and magnetic properties

Ni-Zn ferrites have been widely used in components for high-frequency range applications due to their high electrical resistivity, mechanical strength and chemical stability. Ni-Zn ferrite nanopowders doped with samarium with a nominal composition of Ni0.5Zn0.5Fe2-xSmxO4 (x = 0.0, 0.05, and 0.1 mol) were obtained by combustion synthesis using nitrates and urea as fuel. The morphological aspects of Ni-Zn-Sm ferrite nanopowders were investigated by X-ray diffraction, nitrogen adsorption by BET, sedimentation, scanning electron microscopy and magnetic properties. The results indicated that the Ni-Zn-Sm ferrite nanopowders were composed of soft agglomerates of nanoparticles with a high surface area (55.8-64.8 m(2)/g), smaller particles (18-20 nm) and nanocrystallite size particles. The addition of samarium resulted in a reduction of all the magnetic parameters evaluated, namely saturation magnetization (24-40 emu/g), remanent magnetization (2.2-3.5 emu/g) and coercive force (99.3-83.3 Oe). (c) 2007 Elsevier B. V. All rights reserved.

Luminescence and defect centres in Tb(3+) doped LaMgAl(11)O(19) phosphors

Terbium (Tb) doped LaMgAl(11)O(19) phosphors have been prepared by the combustion of corresponding metal nitrates (oxidizer) and urea (fuel) at furnace temperature as low as 500 C Combustion synthesized powder phosphor was characterized by X-ray diffraction and field emission scanning electron microscopy techniques LaMgAl(11)O(19) doped with trivalent terbium ions emit weakly in blue and orange light region and strongly in green light region when excited by the ultraviolet light of 261 nm Electron Spin Resonance (ESR) studies were carried out to study the defect centres Induced in the phosphor by gamma irradiation and also to identify the defect centres responsible for the thermally stimulated luminescence (TSL) process Room temperature ESR spectrum of irradiated phosphor appears to be a superposition of at least two defect centres One of the centres (centre I) with principal g-values g(parallel to) = 2 0417 and g(perpendicular to) = 2 0041 is identified as O(2)(-) ion while centre II with an axially symmetric g-tensor with principal values g(parallel to) = 19698 and g(perpendicular to) = 1 9653 is assigned to an F(+) centre (singly ionized oxygen vacancy) An additional defect centre is observed during thermal annealing experiments and this centre (assigned to F(+) centre) seems to originate from an F centre (oxygen vacancy with two electrons) The F centre and also the F+ centre appear to correlate with the observed high temperature TSL peak in LaMgAl(11)O(19) Tb phosphor (C) 2010 Elsevier Masson SAS All rights reserved

CuO and CuO-ZnO catalysts supported on CeO(2) and CeO(2)-LaO(3) for low temperature water-gas shift reaction

This paper describes an investigation on CuO and CuO-ZnO catalysts supported on CeO(2) and CeO(2)-La(2)O(3) oxides, which were designed for the low temperature water-gas shift reaction (WGSR). Bulk catalysts were prepared by co-precipitation of metal nitrates and characterized by energy-dispersive spectroscopy (EDS), X-ray diffraction (XRD), surface area (by the BET method), X-ray photoelectron spectroscopy (XPS), and in situ X-ray absorption near edge structure (XANES). The catalysts` activities were tested in the forward WGSR, and the CuO/CeO(2) catalyst presented the best catalytic performance. The reasons for this are twofold: (1) the presence of Zn inhibits the interaction between Cu and Ce ions, and (2) lanthanum oxide forms a solid solution with cerium oxide, which will cause a decrease in the surface area of the catalysts. Also the CuO/CeO(2) catalyst presented the highest Cu content on the surface, which could influence its catalytic behavior. Additionally, the Cu and Cu(1+) species could influence the catalytic activity via a reduction-oxidation mechanism, corroborating to the best catalytic performance of the Cu/Ce catalyst. (c) 2010 Elsevier B.V. All rights reserved.

Quenching of excited states of red-pigment zinc protoporphyrin IX by hemin and natural reductors in dry-cured hams

Zinc protoporphyrin IX (ZnPP), the major red pigment in hams dry-cured without nitrates/nitrites, is an efficient photosensitizer, which upon absorption of visible light forms short-lived excited singlet state ((1)ZnPP*) and by intersystem crossing yields the very reactive triplet-excited state ((3)ZnPP*). Using nano-second laser flash photolysis and transient absorption spectroscopy NADH, ascorbic acid, hemin and dehydroascorbic acid were each found to be efficient quenchers of (3)ZnPP*. The deactivation followed, in homogeneous dimethyl sulfoxide (DMSO) or DMSO:water (1:1) solutions, second-order kinetics. The rate constant for ascorbic acid and NADH for reductive quenching of (3)ZnPP* was at 25 A degrees C found to be 7.5 +/- A 0.1 x 10(4) L mol(-1) s(-1) and 6.3 +/- A 0.1 x 10(5) L mol(-1) s(-1), respectively. The polyphenols catechin and quercetin had no effect on (3)ZnPP*. The quenching rate constant for oxidative deactivation of (3)ZnPP* by dehydroascorbic acid and hemin was at 25 A degrees C: 1.6 +/- A 0.1 x 10(5) L mol(-1) s(-1) and 1.47 +/- A 0.1 x 10(9) L mol(-1) s(-1), respectively. Oxidized glutathione did not act as an oxidative quencher for (3)ZnPP*. After photoexcitation of ZnPP to (1)ZnPP*, fluorescence was only found to be quenched by the presence of hemin in a diffusion-controlled reaction. The efficient deactivation of (3)ZnPP* and (1)ZnPP* by the metalloporphyrin (hemin) naturally present in meat may accordingly inherently protect meat proteins and lipids against ZnPP photosensitized oxidation.

Projeto café do trabalhador como promotor de segurança alimentar e nutricional: avaliação da eficácia da unidade Natal-RN

The evaluation of public policies that promote Food Security and Nutrition (FSN) it s a multidisciplinary activity extremely relevant to the effectiveness of actions to legitimize the Human Right to Adequate Food (HRAF). This study aimed at assessing the effectiveness of the unit project Natal-RN Café do Trabalhador in promoting SAN to its users. The theoretical framework is based on the public and political and on the dimensions of the concept of FSN (quantity and quality-regularity). Through a qualitative approach, methodologically this was the work of an evaluation of efficiency of the unit Natal-RN of Café do Trabalhador project in light of the assumptions of the concept of SAN. Data collection was conducted through retrospective archival research in official documents of the project, semi-structured interviews with managers involved in its implementation (representative of the Secretary of State for Employment, Housing and Care of RN SETHAS and third party), socioeconomic questionnaire applied to the users of the unit, check the amount, regularity and quality of meals offered for 15 days (menu routine) using the descriptive form menu and form filling type checklist for verification of compliance with good practices . Methods of analysis, we used content analysis, descriptive statistics and compared to previously established parameters for the project. As categories of analysis were defined organizational arrangement, access, user, food quantity-regularity and food quality. The results show that, it was found in the category arrangement that will implement the project dismissed technical criteria for choosing the districts and the quantitative distribution of meals for each location. It was found that the valuation of the shares of the company outsources technical SETHA has not been performed. We observed in the access category, the unit has a strategic location, but lack of space in the refectory. The main obstacle to economic access for users is the lack of a register for the beneficiaries. In the category of users, it was identified that the clientele of the project it is predominantly men, with more than 51 years, low education, earning wages less 1 obtained through informal employment, which they move up through the unit transport collective, go to all days of operation due primarily to price. About the meals category quantity-regularity of food showed that the menu serves 95% of the desired needs, and that holidays and weekends are periods of disrupting the regularity of supply of meals. Regarding the category of food quality, it was found that the nutritional aspect on the menu are food sources rich in sodium, nitrates and low in fiber. In the aspect of hygiene and sanitation are the main limitations related to waste management, lack of exposure controls of food prepared and inadequacies of the physical structure. The results showed that in general and the institutional arrangement of the organs attached to the project should establish a systematic evaluation project is to establish as a promoter of and FSN overcome these obstacles

Síntese, caracterização e cinética da decomposição térmica dos materiais cerâmicos PrMO3 (M = Ni ou Co)

In this work have been studied the preparation, characterization and kinetic study of decomposition of the polymerizing agent used in the synthesis under non-isothermal condition ceramics PrMO3 of general formula (M = Co and Ni). These materials were obtained starting from the respective metal nitrates, as a cations source, and making use of gelatin as polymerizing agent. The powders were calcined at temperatures of 500°C, 700°C and 900°C and characterized by X-ray Diffraction (XRD), Thermogravimetric Analysis (TG / DTG/ DTA), Infrared Spectroscopy (FTIR), Temperature Programmed Reduction (TPR) and Scanning Electron Microscopy (SEM). The perovskite phase was detected in all the X-rays patterns. In the infrared spectroscopy observed the oxide formation as the calcination temperature increases with the appearance of the band metal - oxygen. The images of SEM revealed uniform distribution for the PrCoO3 and particles agglomerated as consequence of particle size for PrNiO3. From the data of thermal analysis, the kinetics of decomposition of organic matter was employed using the kinetics methods called Model Free Kinetics and Flynn and Wall, in the heating ratios 10, 20 and 30° C.min-1 between room temperature and 700°C. Finally, been obtained the values of activation energy for the region of greatest decomposition of organic matter in samples that were determined by the degree of conversion (α)

Impregnação de metais em xisto retortado para uso como adsorventes

Concern with the environment has lead to an increase in the research for new adsorption techniques, low cost adsorvent materials and with high availability. Many works search the development of higher selectivity modified adsorvents. The Brazil has the second world reserve of oiled shale, because of it, the use of that reject is of great interest. This study has the goal of characterize and analyze the retorted shale, reject of the pirobetuminous shale pyrolysis, and the retorted shale modified through the humid impregnation method, wich the precursors were the metals nitrates ( Cobalt, Nickel and Copper), to the usage has adsorvent materials. The samples were characterized chemically, textually and structurally by the X ray fluorescence (XRF), BET, X ray diffraction (XRD) and scanning electronic microscopy (SEM) techniques. The impregnated samples showed a reduction in the superficial area and in the pore volume when compared with the retorted shale. Besides that, diffractions referred to the impregnated metals where observed in the XRD analysis, wich were the same metals detected in the XRF and SEM analysis. The materials showed homogeneity in it s composition. The results shows that the materials presents adequate adsorption characteristics

Anti-leishmanial effects of purified compounds from aerial parts of Baccharis uncinella C. DC. (Asteraceae)

Species of Baccharis exhibit antibiotic, antiseptic, wound-healing, and anti-protozoal properties, and have been used in the traditional medicine of South America for the treatment of several diseases. In the present work, the fractionation of EtOH extract from aerial parts of Baccharis uncinella indicated that the isolated compounds caffeic acid and pectolinaringenin showed inhibitory activity against Leishmania (L.) amazonensis and Leishmania (V.) braziliensis promastigotes, respectively. Moreover, amastigote forms of both species were highly sensible to the fraction composed by oleanolic + ursolic acids and pectolinaringenin. Caffeic acid also inhibited amastigote forms of L. (L.) amazonensis, but this effect was weak in L. (V.) braziliensis amastigotes. The treatment of infected macrophages with these compounds did not alter the levels of nitrates, indicating a direct effect of the compounds on amastigote stages. The results presented herein suggest that the active components from B. uncinella can be important to the design of new drugs against American tegumentar leishmaniases.

Isolation and characterization of Flavobacterium columnare (Bernardet et al. 2002) from four tropical fish species in Brazil

Flavobacterium columnare é o agente etiológico da columnariose em peixes de água doce, ocasionando enfermidade na pele e nas brânquias, provocando freqüentemente um grande número de mortalidade. O objetivo deste estudo foi o isolamento e a caracterização de Flavobacterium columnare em peixes tropicais no Brasil. Piracanjuba (Brycon orbignyanus), pacu (Piaractus mesopotamicus), tambaqui (Colossoma macropomum) e cascudo (Hypostomus plecostomus) foram examinados externamente com relação a sinais característicos de columnariose, como manchas acinzentadas na cabeça, região dorsal e pedúnculo caudal dos peixes. A amostragem compreendeu a coleta de 50 exemplares de peixes, representando as quatro diferentes espécies escolhidas para este estudo. Amostras para o isolamento foram obtidas através de raspado com swab estéril das lesões e do rim dos peixes clinicamente diagnosticados como acometidos por columnarios e imediatamente semeados em meios de culturas artificiais (líquido e sólido) próprios para o estudo de Flavobacterium segundo Carlson e Pacha (1968). No meio líquido, houve o desenvolvimento de microrganismos que observados em gota pendente apresentaram a forma de bacilos finos, longos, móveis por deslizamento. Através da coloração de Gram, apresentaram morfologia de bacilos finos, Gram negativos, agrupados em colunas. em meio sólido, as colônias eram pequenas, cinza-amareladas, com borda em forma de raiz. No total, foram obtidos quatro isolamentos: 01 cepa de Brycon orbignyanus; 01 cepa de Piaractus mesopotamicus; 01 cepa de Colossoma macropomum; e 01 cepa de Hypostomus plecostomus. A caracterização bioquímica das amostras, como absorção do vermelho Congo, produção de flexirrubina, produção de H2S e redução do nitrato, sugere que os isolamentos poderiam ser classificados como Flavobacterium columnare.

Uso da tecnologia de troca iônica no tratamento de águas contaminadas com Nitrato do Aqüífero Dunas-Barreiras, Natal/RN-Brasil

The city of Natal comprises an area of about 170 km² (65,63 squares miles). The Dunas-Barreiras Aquifer is the most important reservoir of the coastal basin of RN. It is being responsible for the water supplying of about 70% of the population, however, due to the sewage disposal system by cesspools and drains, it is presently affected in a great extent by nitrates contamination. Thus, the present work proposes to research the utilization of contaminated water by nitrates of this fountainhead and find cost of the potable water through the ionic exchange technology. This technology consists in the removal of mineral salts by the exchange of cations for one ion of hydrogen (H+), through the passage of water by cationic resin bed and, secondly, by the exchange of the anions for hydroxyl ions (OH-) through a anionic resin bed. The obtained results have showed the waters derived from fountains, big water holes and shallow wells were microbiologically contaminated, while the waters derived from deep wells (above 70 m 76,58 yards) were free of contamination. Thus, only these ones are suitable to the use of ionic technology. The experiments were conducted with the resin IMAC-HP-555 such as kinetic, thermodynamic, and adsorption by fixed bed studies, being obtained several project variables for the experimental column, as follow: work temperature of 25oC; resin maximum capacity maximum e mean of adsorption ==0,01692 g NO3-1/g R e 0,0110 g NO3-1/g R, respectively. On the experimental column were performed breakthrough tests which pointed for an average ideal average speed of work of 13.2 m / h, with an average efficiency of 45% of adsorption, an optimal concentration of NaCl desorption of 8%, and an ideal desorption time of 80 minutes for the equilibrium conditions of water from the Dunas-Barreiras aquifer. Scale projection for ion-exchange column for denitrification, for these variables, using a computer modeling programme, to project the column of ion exchange ROREX-420/2000, obtained a cost for the drinking water denitrified by this system of R$ 0,16 / m3