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Sample records for europium silicates

  1. Synthesis and optical features of an europium organic-inorganic silicate hybrid

    Energy Technology Data Exchange (ETDEWEB)

    Franville, A.C.; Zambon, D.; Mahiou, R.; Chou, S.; Cousseins, J.C. [Universite Blaise Pascal, Aubiere (France). Lab. des Materiaux Inorganiques; Troin, Y. [Laboratoire de Chimie des Heterocycles et des Glucides, EA 987, Universite Blaise-Pascal and ENSCCF, F-63177 Aubiere Cedex (France)

    1998-07-24

    A europium organic-inorganic silicate hybrid was synthesized by grafting a coordinative group (dipicolinic acid) to a silicate network precursor (3-aminopropyltriethoxysilane) via a covalent bonding. Sol-gel process and complexation were performed using different experimental conditions. The hybrid materials, in particular the Eu{sup 3+} coordination mode, were characterized by infrared and luminescence spectroscopies. Morphology of the materials and TG analysis showed that grafted silica enhanced thermal and mechanical resistances of the organic part. (orig.) 7 refs.

  2. Sol-Gel Synthesis, X-Ray Diffraction Studies, and Electric Conductivity of Sodium Europium Silicate

    Directory of Open Access Journals (Sweden)

    Ekaterina V. Borisova

    2013-01-01

    Full Text Available Sodium europium silicate, NaEu9(SiO46O2, with apatite structure has been obtained and studied using X-ray diffraction and SEM. It has been shown that sodium sublimation does not take place upon synthesis by the sol-gel method. Rietveld refinement has revealed that sodium atoms are ordered and occupy the 4f position. O(4 atoms not related to silicate ions are placed at the centers of Eu(2 triangles. DC and AC electric conductivity and activation energy have been determined for the compound studied.

  3. Sorption of Europium in zirconium silicate; Sorcion de Europio en silicato de circonio

    Energy Technology Data Exchange (ETDEWEB)

    Garcia R, G. [ININ, Carretera Mexico-Toluca Km. 36.5, 52045 Estado de Mexico (Mexico)

    2004-07-01

    Some minerals have the property of sipping radioactive metals in solution, that it takes advantage to manufacture contention barriers that are placed in the repositories of nuclear wastes. The more recent investigations are focused in the development of new technologies guided to the sorption of alpha emissors on minerals which avoid their dispersion in the environment. In an effort to contribute to the understanding of this type of properties, some studies of sorption of Europium III are presented like homologous of the americium, on the surface of zirconium silicate (ZrSiO{sub 4}). In this work the results of sorption experiences are presented as well as the interpretation of the phenomena of the formation of species in the surface of the zirconium silicate. (Author)

  4. TOF SIMS analysis and generation of white photoluminescence from strontium silicate codoped with europium and terbium

    Energy Technology Data Exchange (ETDEWEB)

    Tshabalala, Modiehi A.; Swart, Hendrik C.; Ntwaeaborwa, Odireleng M., E-mail: ntwaeab@ufs.ac.za [Department of Physics, University of the Free State, P.O Box 339, Bloemfontein 9300 South Africa (South Africa)

    2014-03-15

    White light emitting terbium (Tb{sup 3+}) and europium (Eu{sup 3+}) codoped strontium silicate (Sr{sub 2}SiO{sub 4}) phosphors were prepared by a solid state reaction process. The structure, particle morphology, chemical composition, ion distribution, photoluminescence (PL), and decay characteristics of the phosphors were analyzed by x-ray diffraction (XRD), scanning electron microscopy (SEM), time-of-flight secondary ion mass spectrometry (TOF-SIMS), and PL spectroscopy, respectively. The XRD data showed that our Sr{sub 2}SiO{sub 4} composed of two phases, namely, β-Sr{sub 2}SiO{sub 4} and α′-Sr{sub 2}SiO{sub 4}, and the α′-Sr{sub 2}SiO{sub 4} phase was more prominent than the β-Sr{sub 2}SiO{sub 4} phase. The SEM micrographs showed that the particles were agglomerated together and they did not have definite shapes. All ions (i.e., negative and positive) present in our materials were identified by TOF-SIMS. In addition, the chemical imaging performed with the TOF-SIMS demonstrated how the individual ions including the dopants (Eu{sup 3+} and Tb{sup 3+}) were distributed in the host lattice. White photoluminescence was observed when the Sr{sub 2}SiO{sub 4}:Tb{sup 3+}, Eu{sup 3+} phosphor was excited at 239 nm using a monochromatized xenon lamp as the excitation source. The phosphor exhibited fast decay lifetimes implying that it is not a good candidate for long afterglow applications.

  5. Orange-red emitting europium doped strontium ortho-silicate phosphor prepared by a solid state reaction method.

    Science.gov (United States)

    Sahu, Ishwar Prasad

    2017-05-01

    In the present article we report europium-doped strontium ortho-silicates, namely Sr 2 SiO 4 :xEu 3+ (x = 1.0, 1.5, 2.0, 2.5 or 3.0 mol%) phosphors, prepared by solid state reaction method. The crystal structures of the sintered phosphors were consistent with orthorhombic crystallography with a Pmna space group. The chemical compositions of the sintered phosphors were confirmed by energy dispersive X-ray spectroscopy (EDS). Thermoluminescence (TL) kinetic parameters such as activation energy, order of kinetics and frequency factors were calculated by the peak shape method. Orange-red emission originating from the 5 D 0 - 7 F J (J = 0, 1, 2, 3) transitions of Eu 3+ ions could clearly be observed after samples were excited at 395 nm. The combination of these emissions constituted orange-red light as indicated on the Commission Internationale de l'Eclairage (CIE) chromaticity diagram. Mechanoluminescence (ML) intensity of the prepared phosphor increased linearly with increasing impact velocity of the moving piston that suggests that these phosphors can also be used as sensors to detect the stress of an object. Thus, the present investigation indicates that the piezo-electricity was responsible for producing ML in the prepared phosphor. Copyright © 2016 John Wiley & Sons, Ltd.

  6. Photoluminescence properties of europium doped di-strontium magnesium di-silicate phosphor by solid state reaction method

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    Ishwar Prasad Sahu

    2015-01-01

    Full Text Available Europium doped di-strontium magnesium di-silicate phosphor namely (Sr2MgSi2O7:Eu3+ was prepared by the traditional high temperature solid state reaction method. The phase structure of sintered phosphor was akermanite type structure which belongs to the tetragonal crystallography with space group P42¯1m, this structure is a member of the melilite group and forms a layered compound. The EDX and FTIR spectra confirm the present elements in Sr2MgSi2O7:Eu3+ phosphor. Photoluminescence measurements showed that the phosphor exhibited strong emission peak with good intensity, corresponding to 5D0 → 7F2 (613 nm red emission and weak 5D0 → 7F1 (590 nm orange emission. The excitation spectra monitored at 613 nm show broad band from 220 to 300 nm ascribed to O–Eu charge-transfer band (CTB centered at about 269 nm, and the other peaks in the range of 300–400 nm originated from f–f transitions of Eu3+ ions. The strongest band at 395 nm can be assigned to 7F0 / 5L6 transition of Eu3+ ions due to the typical f–f transitions within Eu3+ of 4f6 configuration.

  7. Europium doped di-calcium magnesium di-silicate orange–red emitting phosphor by solid state reaction method

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    Ishwar Prasad Sahu

    2015-07-01

    Full Text Available A new orange–red europium doped di-calcium magnesium di-silicate (Ca2MgSi2O7:Eu3+ phosphor was prepared by the traditional high temperature solid state reaction method. The prepared Ca2MgSi2O7:Eu3+ phosphor was characterized by X-ray diffractometer (XRD, transmission electron microscopy (TEM, field emission scanning electron microscopy (FESEM with energy dispersive x-ray spectroscopy (EDX, fourier transform infrared spectra (FTIR, photoluminescence (PL and decay characteristics. The phase structure of sintered phosphor was akermanite type structure which belongs to the tetragonal crystallography with space group P4¯21m, this structure is a member of the melilite group and forms a layered compound. The chemical composition of the sintered Ca2MgSi2O7:Eu3+ phosphor was confirmed by EDX spectra. The PL spectra indicate that Ca2MgSi2O7:Eu3+ can be excited effectively by near ultraviolet (NUV light and exhibit bright orange–red emission with excellent color stability. The fluorescence lifetime of Ca2MgSi2O7:Eu3+ phosphor was found to be 28.47 ms. CIE color coordinates of Ca2MgSi2O7:Eu3+ phosphor is suitable as orange-red light emitting phosphor with a CIE value of (X = 0.5554, Y = 0.4397. Therefore, it is considered to be a new promising orange–red emitting phosphor for white light emitting diode (LED application.

  8. Sorption behavior of cesium, cobalt and europium radionuclides onto hydroxyl magnesium silicate

    Energy Technology Data Exchange (ETDEWEB)

    Hamed, Mostafa M.; Holiel, M.; Ahmed, I.M. [Atomic Energy Authority, Cairo (Egypt). Hot Laboratories and Waste Management Center

    2016-07-01

    The radioactive wastes from different activities have to be safely disposed of and isolated from the human environment. The retardation of radioactive materials by designed barriers is originally controlled by the sorption ability of the mineral compositions. In this work, a naturally available mineral composite, a hydroxyl magnesium silicate (HMS) was investigated as potential natural inorganic sorbent for the retention of long-lived radionuclides ({sup 134}Cs, {sup 60}Co and {sup 152+154}Eu) from aqueous solutions. The factors affecting the sorption process, such as contact time and pH were evaluated. Furthermore X-ray fluorescence (XRF), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), X-ray diffraction (XRD), differential thermal and thermogravimetry analyses (DTA/TGA) measurements were examined in order to assess the physicochemical properties of the magnesium silicate mineral. Langmuir and Freundlich isotherms fitted the result s substantially better than the Flory-Huggins isotherm and the sorption was found to follow pseudo-first order kinetic model. The proposed mineral has been successfully applied for the sorption of {sup 134}Cs, {sup 60}Co and {sup 152+154}Eu radionuclides from real radioactive waste. The results indicated that about 97.4-99% of {sup 134}Cs, {sup 60}Co and {sup 152+154}Eu radionuclides were efficiently retained onto the HMS mineral. Based on the results obtained, it can be concluded that the HMS mineral is an economic and efficient retaining material for environmental hazardous migration and/or leakage of some radionuclides such as {sup 134}Cs, {sup 60}Co and {sup 152+154}Eu and trivalent actinide ({sup 241}Am, {sup 242m}Am and {sup 243}Am) ions. Therefore, this study could be used as a starting point to establish and consider that mineral as an engineered barrier around the disposal facilities at the nuclear activity centres.

  9. Study of sorption mechanisms of europium(3) and uranium(6) ions on clays : impact of silicates; Etude des mecanismes de retention des ions U(6) et Eu(3) sur les argiles: influence des silicates

    Energy Technology Data Exchange (ETDEWEB)

    Kowal-Fouchard, A

    2002-11-01

    Bentonite clay has been selected as a potential buffer or backfill material in a number of disposal programmes for high level waste. In order to enhance the thermodynamic database of sorption phenomena at the solid-water interface, we have investigated sorption mechanisms of europium(III) and uranium(VI) ions onto montmorillonite and bentonite. Thermodynamic data were obtained for different ions concentrations, different background electrolytes and different ionic strengths. The structural identification of the surface complexes and sorption sites was carried out using two spectroscopies, XPS and TRLIFS, while sorption edges were performed using batch experiments. However, clays are complex minerals and in order to understand these sorption mechanisms we have studied europium(III) and uranium(VI) retention on a silica and an alumina because these solids are often considered as basic components of clays. The comparison of structural results shows that europium ions are significantly sorbed on permanently charged sites of clay until pH 7. But this ion is also sorbed on {identical_to}SiOH and {identical_to}AlOH sites of montmorillonite at pH higher than 6. Uranyl ions sorption on montmorillonite is mainly explained by retention of three complexes on {identical_to}SiOH sites. Moreover, we have shown that nitrate ions and dissolved silicates affect on uranium(VI) sorption mechanisms onto alumina. Nevertheless, uranyl ions sorption on montmorillonite and bentonite only decreases with increasing carbonate concentration. Finally, all the sorption edges were then modeled using these results and a surface complexation model (2 pK and constant capacitance models). (author)

  10. 40 CFR 721.9511 - Silicic acid (H6SiO2O7), magnesium, strontium salt(1:1:2), dysprosium and europium-doped.

    Science.gov (United States)

    2010-07-01

    ..., strontium salt(1:1:2), dysprosium and europium-doped. 721.9511 Section 721.9511 Protection of Environment...), magnesium, strontium salt(1:1:2), dysprosium and europium-doped. (a) Chemical substance and significant new..., strontium salt(1:1:2), dysprosium and europium-doped. (PMN P-98-848; CAS No.181828-07-9) is subject to...

  11. Fluorescent Europium Chelate Stain

    Science.gov (United States)

    Scaff, W. L.; Dyer, D. L.; Mori, K.

    1969-01-01

    The europium chelate of 4,4,4-trifluoro-1-(2-thienyl)-1,3-butanedione (thenoyl-trifluoroacetone; TTA) is firmly bound to microorganisms. It fluoresces brightly at 613 nm with activation at 340 nm. Cells may be stained with 10−3m chelate in 50% ethyl alcohol, followed by washing with 50% ethyl alcohol. Equal or better stains are produced with 10−3m aqueous europium salt, water wash, and 10−2m aqueous TTA. A noncomplexing buffer should be used to maintain the pH at 6.5 to 6.8. Images PMID:4181107

  12. Europium-155 in Debris from Nuclear Weapons

    DEFF Research Database (Denmark)

    Aarkrog, Asker; Lippert, Jørgen Emil

    1967-01-01

    The lithium-drifted germanium detector enables determination of europium-155 on a routine basis in environmental samples contaminated with debris from nuclear weapons. From measurements of europium-155, cesium-144, and strontium-90 in air filters collected between 1961 and 1966, the yield...... of europium-155 from weapons was estimated at 1400 atoms per 10$^{6}$ fissions, which is close to the yield of europium-155 from fast fission of uranium-238....

  13. The electrochemical synthesis of europium boride

    Directory of Open Access Journals (Sweden)

    Bukatova G.A.

    2003-01-01

    Full Text Available The electroreduction of boron, europium and the electrochemical synthesis of europium boride have been investigated in NaCl-KCl-NaF(10 wt. % melt on silver and molybdenum electrodes. The parameters of boron reduction in the chloride-fluoride melt have been obtained and the character of its joint deposition with europium has been studied.

  14. The electrochemical synthesis of europium boride

    OpenAIRE

    Bukatova G.A.; Kuznetsov S.A.; Gaune-Escard M.

    2003-01-01

    The electroreduction of boron, europium and the electrochemical synthesis of europium boride have been investigated in NaCl-KCl-NaF(10 wt. %) melt on silver and molybdenum electrodes. The parameters of boron reduction in the chloride-fluoride melt have been obtained and the character of its joint deposition with europium has been studied.

  15. Liposome Biodistribution via Europium Complexes.

    Science.gov (United States)

    Mignet, Nathalie; Scherman, Daniel

    2017-01-01

    The drug delivery field needs tools to follow vector biodistribution. Radioactive tracers and conventional fluorophores are widely used. We propose here to use europium complexes. Use of pulsed light source time-resolved fluorimetry takes into account the fluorescence decay time of the lanthanide chelates to gain sensitivity in biological media. The method was developed to follow liposome biodistribution. Octadecyl-DTPA.Eu compound has been prepared and incorporated into liposomes without alteration of its fluorescence signal. The method has been validated by comparison with fluorophore-labeled liposomes. The way to proceed to use this method for liposomes or other vectors is detailed.

  16. Resonance ionization scheme development for europium

    CERN Document Server

    Chrysalidis, K; Fedosseev, V N; Marsh, B A; Naubereit, P; Rothe, S; Seiffert, C; Kron, T; Wendt, K

    2017-01-01

    Odd-parity autoionizing states of europium have been investigated by resonance ionization spectroscopy via two-step, two-resonance excitations. The aim of this work was to establish ionization schemes specifically suited for europium ion beam production using the ISOLDE Resonance Ionization Laser Ion Source (RILIS). 13 new RILIS-compatible ionization schemes are proposed. The scheme development was the first application of the Photo Ionization Spectroscopy Apparatus (PISA) which has recently been integrated into the RILIS setup.

  17. Resonance ionization scheme development for europium

    Energy Technology Data Exchange (ETDEWEB)

    Chrysalidis, K., E-mail: katerina.chrysalidis@cern.ch; Goodacre, T. Day; Fedosseev, V. N.; Marsh, B. A. [CERN (Switzerland); Naubereit, P. [Johannes Gutenberg-Universität, Institiut für Physik (Germany); Rothe, S.; Seiffert, C. [CERN (Switzerland); Kron, T.; Wendt, K. [Johannes Gutenberg-Universität, Institiut für Physik (Germany)

    2017-11-15

    Odd-parity autoionizing states of europium have been investigated by resonance ionization spectroscopy via two-step, two-resonance excitations. The aim of this work was to establish ionization schemes specifically suited for europium ion beam production using the ISOLDE Resonance Ionization Laser Ion Source (RILIS). 13 new RILIS-compatible ionization schemes are proposed. The scheme development was the first application of the Photo Ionization Spectroscopy Apparatus (PISA) which has recently been integrated into the RILIS setup.

  18. Test of zircon materials for sorption of europium; Pruebas de materiales circoniferos para sorcion de europio

    Energy Technology Data Exchange (ETDEWEB)

    Ordonez R, E.; Fernandez V, S.M.; Garcia R, G. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico)

    2003-07-01

    In previous works it has already been made notice that some phosphates have the property of sipping radioactive metals in solution, what takes advantage to fabricate reactive barriers that are placed in the repositories of nuclear wastes. In our laboratory it has been obtained to the zirconium silicate (ZrSiO{sub 4}) and the alpha zirconium hydrogen phosphate (Zr(HPO{sub 4}) 2H{sub 2}0) starting from sea sand in an easy and economic way. With the interest of knowing if these compounds can be used in contention barriers the evaluation of their surface properties it is made and of europium sorption. (Author)

  19. Electronic state of europium atoms on surface of oxidized tungsten

    CERN Document Server

    Davydov, S Y

    2001-01-01

    The energy scheme of the europium atoms adsorption system on the tungsten surface, coated with the oxygen monolayer, is considered. The evaluations of the europium adatoms charged state on the oxidized tungsten surface are performed. It is established, that europium, adsorbed at the oxidized tungsten surface, is a positive ion with the charge close to the unit. The zonal scheme of the Eu-O/W adsorption system for the europium low and high concentrations is proposed

  20. Europium anomaly in plagioclase feldspar - Experimental results and semiquantitative model.

    Science.gov (United States)

    Weill, D. F.; Drake, M. J.

    1973-01-01

    The partition of europium between plagioclase feldspar and magmatic liquid is considered in terms of the distribution coefficients for divalent and trivalent europium. A model equation is derived giving the europium anomaly in plagioclase as a function of temperature and oxygen fugacity. The model explains europium anomalies in plagioclase synthesized under controlled laboratory conditions as well as the variations of the anomaly observed in natural terrestrial and extraterrestrial igneous rocks.

  1. Fermi Surface and Antiferromagnetism in Europium Metal

    DEFF Research Database (Denmark)

    Andersen, O. Krogh; Loucks, T. L.

    1968-01-01

    We have calculated the Fermi surface of europium in order to find those features which determine the wave vector of the helical moment arrangement below the Néel point. We find that there are two pieces of Fermi surface: an electron surface at the symmetry point H, which has the shape of rounded...... of the nearly cubical part of the hole surface at P, and we also discuss the effects of the electron surface at H. Since it is likely that barium and europium have similar Fermi surfaces, we have presented several extremal areas and the corresponding de Haas-van Alphen frequencies in the hope that experimental...

  2. Organophosphate Nerve Agent Detection with Europium Complexes

    Directory of Open Access Journals (Sweden)

    Jake R. Schwierking

    2004-01-01

    Full Text Available We explore the detection of paraoxon, a model compound for nonvolatile organophosphate nerve agents such as VX. The detection utilizes europium complexes with 1,10 phenanthroline and thenoyltrifluoroacetone as sensitizing ligands. Both europium luminescence quenching and luminescence enhancement modalities are involved in the detection, which is simple, rapid, and sensitive. It is adaptable as well to the more volatile fluorophosphate nerve agents. It involves nothing more than visual luminescence observation under sample illumination by an ordinary hand-held ultraviolet lamp.

  3. Silicate volcanism on Io

    Science.gov (United States)

    Carr, M. H.

    1986-03-01

    This paper is mainly concerned with the nature of volcanic eruptions on Io, taking into account questions regarding the presence of silicates or sulfur as principal component. Attention is given to the generation of silicate magma, the viscous dissipation in the melt zone, thermal anomalies at eruption sites, and Ionian volcanism. According to the information available about Io, it appears that its volcanism and hence its surface materials are dominantly silicic. Several percent of volatile materials such as sulfur, but also including sodium- and potassium-rich materials, may also be present. The volatile materials at the surface are continually vaporized and melted as a result of the high rates of silicate volcanism.

  4. Nanostructured silicate polymer concrete

    Directory of Open Access Journals (Sweden)

    Figovskiy Oleg L'vovich

    2014-03-01

    Full Text Available It has been known that acid-resistant concretes on the liquid glass basis have high porosity (up to 18~20 %, low strength and insufficient water resistance. Significant increasing of silicate matrix strength and density was carried out by incorporation of special liquid organic alkali-soluble silicate additives, which block superficial pores and reduce concrete shrinkage deformation. It was demonstrated that introduction of tetrafurfuryloxisilane additive sharply increases strength, durability and shock resistance of silicate polymer concrete in aggressive media. The experiments showed, that the strength and density of silicate polymer concrete increase in case of decreasing liquid glass content. The authors obtained optimal content of silicate polymer concrete, which possesses increased strength, durability, density and crack-resistance. Diffusive permeability of concrete and its chemical resistance has been investigated in various corroding media.

  5. Europium enabled luminescent nanoparticles for biomedical applications

    Energy Technology Data Exchange (ETDEWEB)

    Syamchand, S.S., E-mail: syamchand.ss@gmail.com; Sony, G., E-mail: emailtosony@gmail.com

    2015-09-15

    Lanthanide based nanoparticles are receiving great attention ought to their excellent luminescent and magnetic properties and find challenging biomedical applications. Among the luminescent lanthanide NPs, europium based NPs (Eu-NPs) are better candidates for immunoassay and imaging applications. The Eu-NPs have an edge over quantum dots (QDs) by means of their stable luminescence, long fluorescence lifetime, sharp emission peaks with narrow band width, lack of blinking and biocompatibility. This review surveys the synthesis and properties of a variety of Eu-NPs consolidated from different research articles, for their applications in medicine and biology. The exquisite luminescent properties of Eu-NPs are explored for developing biomedical applications such as immunoassay and bioimaging including multimodal imaging. The biomedical applications of Eu-NPs are mostly diagnostic in nature and mainly focus on various key analytes present in biological systems. The luminescent properties of europium enabled NPs are influenced by a number of factors such as the site symmetry, the metal nanoparticles, metal ions, quantum dots, surfactants, morphology of Eu-NPs, crystal defect, phenomena like antenna effect and physical parameters like temperature. Through this review we explore and assimilate all the factors which affect the luminescence in Eu-NPs and coil a new thread of parameters that control the luminescence in Eu-NPs, which would provide further insight in developing Eu-based nanoprobes for future biomedical prospects. - Highlights: • The review describes 14 major factors that influence the luminescence properties of europium enabled luminescent nanoparticles (Eu-NPs). • Surveys different types of europium containing nanoparticles that have been reported for their biomedical applications. • Eu-NPs are conveniently divided into four different categories, based on the type of the substrates involved. The four categories are (1) virgin Eu-substrate based NPs; (2

  6. The Europium Oxybarometer: Power and Pitfalls

    Science.gov (United States)

    McKay, G.

    2004-01-01

    One of the most important characteristics of a planet is the oxidation state of its mantle, as reflected in primitive basalts. Petrologists have devised several methods to estimate the oxygen fugacity under which basalts crystallized. One method that has been the subject of recent interest involves the depth of the Eu anomaly in first-crystallizing minerals. A discussion detailing the experimental calibration of the Europium oxybarometer and the application of this device to Angrites and Martian basaltic meteorites are presented. The strengths and weaknesses of the instrument are also included.

  7. Europium Effect on the Electron Transport in Graphene Ribbons

    Energy Technology Data Exchange (ETDEWEB)

    Bobadilla, Alfredo D.; Ocola, Leonidas E.; Sumant, Anirudha V.; Kaminski, Michael; Kumar, Narendra; Seminario, Jorge M.

    2015-10-01

    We report in this complementary theoretical-experimental work the effect of gating on the election transport of grapheme ribbons when exposed to very low concentration of europium in an aqueous solution. We find a direct correlation between the level of concentration of europium ions in the solvent and the change in electron transport in graphene, observing a change of up to 3 orders of magnitude at the lowest level of concentration tested (0.1 mM), suggesting a possibility that graphene ribbons can be used for detecting very low concentrations of europium in liquid solutions.

  8. Paramagnetic Europium Salen Complex and Sickle-Cell Anemia

    Science.gov (United States)

    Wynter, Clive I.; Ryan, D. H.; May, Leopold; Oliver, F. W.; Brown, Eugene; Hoffman, Eugene J.; Bernstein, David

    2005-04-01

    A new europium salen complex, Eu(salen)2NH4, was synthesized, and its composition was confirmed by chemical analysis and infrared spectroscopy. Further characterization was carried out by 151 Eu Mössbauer spectroscopy and magnetic susceptibility measurements. Mössbauer spectroscopic measurements were made at varying temperatures between 9 K and room temperature and a value of Debye temperature of 133 ±5 K was computed. Both Mössbauer and magnetic susceptibility measurements confirmed the paramagnetic behavior of this complex and the trivalent state of the europium ion. In view of the fact that the "odd" paramagnetic molecule NO has been shown to reverse sickling of red blood cells in sickle cell anemia, the interaction between the paramagnetic europium salen complex and sickle cells was examined after incubation with this europium complex and shown to have similar effects.

  9. Polymer-Layer Silicate Nanocomposites

    DEFF Research Database (Denmark)

    Potarniche, Catalina-Gabriela

    Nowadays, some of the material challenges arise from a performance point of view as well as from recycling and biodegradability. Concerning these aspects, the development of polymer layered silicate nanocomposites can provide possible solutions. This study investigates how to obtain polymer layered...... silicate nanocomposites and their structure-properties relationship. In the first part of the thesis, thermoplastic layered silicates were obtained by extrusion. Different modification methods were tested to observe the intercalation treatment effect on the silicate-modifier interactions. The silicate...

  10. Europium polyoxometalates encapsulated in silica nanoparticles - characterization and photoluminescence studies

    Energy Technology Data Exchange (ETDEWEB)

    Neves, Cristina S.; Granadeiro, Carlos M.; Cunha-Silva, Luis; Eaton, Peter; Balula, Salete S.; Pereira, Eulalia [REQUIMTE/Departamento de Quimica e Bioquimica, Faculdade de Ciencias, Universidade do Porto (Portugal); Ananias, Duarte [CICECO, Departamento de Quimica, Universidade de Aveiro (Portugal); Gago, Sandra [REQUIMTE, Departamento de Quimica, Faculdade de Ciencias e Tecnologia, Universidade Nova de Lisboa, Monte de Caparica (Portugal); Feio, Gabriel [CENIMAT/I3N, Departamento de Ciencia dos Materiais, Faculdade de Ciencias e Tecnologia, Universidade Nova de Lisboa, Monte de Caparica (Portugal); Carvalho, Patricia A. [ICEMS/Departamento de Bioengenharia, Instituto Superior Tecnico, Lisboa (Portugal)

    2013-06-15

    The incorporation of europium polyoxometalates into silica nanoparticles can lead to a biocompatible nanomaterial with luminescent properties suitable for applications in biosensors, biological probes, and imaging. Keggin-type europium polyoxometalates Eu(PW{sub 11}){sub x} (x = 1 and 2) with different europium coordination environments were prepared by using simple methodologies and no expensive reactants. These luminescent compounds were then encapsulated into silica nanoparticles for the first time through the water-in-oil microemulsion methodology with a nonionic surfactant. The europium polyoxometalates and the nanoparticles were characterized by using several techniques [FTIR, FT-Raman, {sup 31}P magic angle spinning (MAS) NMR, and TEM/energy-dispersive X-ray spectroscopy (TEM-EDS), AFM, dynamic light scattering (DLS), and inductively coupled plasma MS (ICP-MS) analysis]. The stability of the material and the integrity of the europium compounds incorporated were also examined. Furthermore, the photoluminescence properties of the Eu(PW{sub 11}){sub x} rate at SiO{sub 2} nanomaterials were evaluated and compared with those of the free europium polyoxometalates. The silica surface of the most stable nanoparticles was successfully functionalized with appropriate organosilanes to enable the covalent binding of oligonucleotides. (Copyright copyright 2013 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  11. Spectral Properties of a bis-Azospiropyran Complexed with Europium

    Science.gov (United States)

    Nourmohammadian, F.; Ghahari, M.; Gholami, M. Davoudzadeh

    2015-09-01

    The complexation of recently synthesized symmetrical bifunctional bis-azospiropyran photochromic dye with europium nitrate and its effect on UV-vis absorption and fluorescent emission was studied. Upon addition of Eu 3+ to colorless spiropyran, a yellow merocyanine europium complex was obtained with an absorption band at 410 nm. Negatively charged phenolic oxygenin zwitterionic ring-open form provides an effective metal binding site for Eu 3+ . Meanwhile, the inherent fluorescence emission of the photochromic dye at 380 nm is switched off due to the Eu 3+ - induced drive of spiro-mero equilibrium to form mero form. The stoichiometry of dye-europium complexation was evaluated by fluorescence emission and UV-vis absorption spectroscopy and a 8:1 ratio was obtained in both cases. The binding constant (K) value of the dye-europium complex was 3 × 106 M -1 . In conclusion, the current molecular switch is a useful sensitive dual measuring tool for solutions containing europium or europium-like elements by evaluation of visible absorption or fluorescent emission spectroscopy.

  12. Metal plasmon enhanced europium complex luminescence

    Energy Technology Data Exchange (ETDEWEB)

    Liu Feng [Department of Chemistry, Queen' s University, 90 Bader Lane, Kingston, Ontario, K7L 3N6 (Canada); Aldea, Gabriela [Department of Chemistry, Queen' s University, 90 Bader Lane, Kingston, Ontario, K7L 3N6 (Canada); Petru Poni Institute of Macromolecular Chemistry Iasi, Aleea Grigore Ghica Voda 41A, 700487 Iasi (Romania); Nunzi, Jean-Michel, E-mail: nunzijm@queensu.c [Department of Chemistry, Queen' s University, 90 Bader Lane, Kingston, Ontario, K7L 3N6 (Canada)

    2010-01-15

    The plasmon enhanced luminescence of a rare-earth complex Tris(6, 6, 7, 7, 8, 8, 8-heptafluoro-2, 2-dimethyl-3, 5-octanedionato) europium (Eu(fod){sub 3}) was investigated. A polyvinyl alcohol (PVA) thin film was successfully adopted as a spacer to separate the Eu complex from the silver island film (SIF), and five-fold enhancement of the radiative decay rate of the Eu complex on SIF was demonstrated based on the luminescence intensity and lifetime measurement. Investigation of the distance dependent luminescence indicates that 7 nm is an optimal distance for SIF enhanced Eu luminescence. Plasmon enhanced rare-earth luminescence based on an organic film spacer would find potential applications in plasmon enhanced organic light emitting diode (OLED) devices.

  13. Novel fluorescent probe for low density lipoprotein, based on the enhancement of Europium emission band

    OpenAIRE

    Courrol, Lilia Coronato; Monteiro, A.M.; SILVA, F.R.O.; L. Gomes; VIEIRA, N.D.; Gidlund, Magnus; Figueiredo Neto, A.M.

    2007-01-01

    We report here the observation of the enhancement of Europium-tetracycline complex emission in Low Density Lipoprotein (LDL) solutions. Europium emission band of tetracycline solution containing Europium (III) chloride hexahydrate was tested to obtain effective enhancement in the presence of native LDL and oxidized LDL. Europium emission lifetime in the presence of lipoproteins was measured, resulting in a simple method to measure the lipoproteins quantity in an aqueous solution at physiologi...

  14. Europium ion as a probe for binding sites to carrageenans

    Energy Technology Data Exchange (ETDEWEB)

    Ramos, Ana P.; Goncalves, Rogeria R.; Serra, Osvaldo A. [Departamento de Quimica, Faculdade de Filosofia, Ciencias e Letras de Ribeirao Preto, Universidade de Sao Paulo, Ribeirao Preto, Sao Paulo 14040-901 (Brazil); Zaniquelli, Maria Elisabete D. [Departamento de Quimica, Faculdade de Filosofia, Ciencias e Letras de Ribeirao Preto, Universidade de Sao Paulo, Ribeirao Preto, Sao Paulo 14040-901 (Brazil)], E-mail: medzaniquelli@ffclrp.usp.br; Wong, Kenneth [Laboratorio de Fisico-Quimica, Centro de Pesquisas de Paulinia, Rhodia Brasil, Paulinia, Sao Paulo (Brazil)

    2007-12-15

    Carrageenans, sulfated polysaccharides extracted from red algae, present a coil-helix transition and helix aggregation dependence on the type and concentration of counterions. In this study, we focus attention on a mixed valence counterion system: Eu{sup 3+}/Na{sup +} or K{sup +} with different gel-forming carrageenans: kappa, iota, and kappa-2. Results of stationary and time-dependent luminescence showed to be a suitable tool to probe ion binding to both the negatively charged sulfate group and the hydroxyl groups present in the biopolymer. For lower europium ion concentrations, a single longer decay emission lifetime was detected, which was attributed to the binding of europium ion to the carrageenan sulfate groups. An additional decay ascribed to europium binding to hydroxyl groups was observed above a threshold concentration, and this decay was dependent on the carrageenan charge density. Symmetry of the europium ion microenvironment was estimated by the ratio between the intensities of its emission bands, which has been shown to depend on the concentration of europium ions and on the specificity of the monovalent counterion bound to the carrageenan.

  15. First-Principles Investigations on Europium Monoxide

    KAUST Repository

    Wang, Hao

    2011-05-01

    Europium monoxide is both an insulator and a Heisenberg ferromagnet (Tc=69 K). In the present thesis, the author has investigated the electronic structure of different types of EuO by density functional theory. The on-site Coulomb interaction of the localized Eu 4f and 5d electrons, which is wrongly treated in the standard generalized gradient approximation method, is found to be crucial to obtain the correct insulating ground state as observed in experiments. Our results show that the ferromagnetism is stable under pressure, both hydrostatic and uniaxial. For both types of pressure an insulator-metal transition is demonstrated. Moreover, the experimentally observed insulator-metal transition in oxygen deficient and gadolinium-doped EuO is reproduced in our calculations for impurity concentrations of 6.25% and 25%. Furthermore, a 10- layer EuO thin film is theoretically predicted to be an insulator with a narrow band gap of around 0.08 eV, while the Si/EuO interface shows metallic properties with the Si and O 2p as well as Eu 5d bands crossing the Fermi level.

  16. Chloride, bromide and iodide scintillators with europium

    Science.gov (United States)

    Zhuravleva, Mariya; Yang, Kan

    2016-09-27

    A halide scintillator material is disclosed where the halide may comprise chloride, bromide or iodide. The material is single-crystalline and has a composition of the general formula ABX.sub.3 where A is an alkali, B is an alkali earth and X is a halide which general composition was investigated. In particular, crystals of the formula ACa.sub.1-yEu.sub.yI.sub.3 where A=K, Rb and Cs were formed as well as crystals of the formula CsA.sub.1-yEu.sub.yX.sub.3 (where A=Ca, Sr, Ba, or a combination thereof and X=Cl, Br or I or a combination thereof) with divalent Europium doping where 0.ltoreq.y.ltoreq.1, and more particularly Eu doping has been studied at one to ten mol %. The disclosed scintillator materials are suitable for making scintillation detectors used in applications such as medical imaging and homeland security.

  17. Electrochemical extraction of europium from molten fluoride media

    Energy Technology Data Exchange (ETDEWEB)

    Gibilaro, M. [Universite de Toulouse, INPT, UPS, Laboratoire de Genie Chimique, Departement Procedes Electrochimiques, F-31062 Toulouse cedex 09 (France); CNRS, Laboratoire de Genie Chimique, F-31062 Toulouse cedex 09 (France); Massot, L., E-mail: massot@chimie.ups-tlse.f [Universite de Toulouse, INPT, UPS, Laboratoire de Genie Chimique, Departement Procedes Electrochimiques, F-31062 Toulouse cedex 09 (France); CNRS, Laboratoire de Genie Chimique, F-31062 Toulouse cedex 09 (France); Chamelot, P.; Cassayre, L.; Taxil, P. [Universite de Toulouse, INPT, UPS, Laboratoire de Genie Chimique, Departement Procedes Electrochimiques, F-31062 Toulouse cedex 09 (France); CNRS, Laboratoire de Genie Chimique, F-31062 Toulouse cedex 09 (France)

    2009-12-15

    This work concerns the extraction of europium from molten fluoride media. Two electrochemical ways have been examined: (i) the use of a reactive cathode made of copper and (ii) the co-deposition with aluminium on inert electrode, leading to the formation of europium-copper and europium-aluminium alloys, respectively, as identified by SEM-EDS analysis. Cyclic voltammetry and square wave voltammetry were used to identify the reduction pathway and to characterise the step of Cu-Eu and Al-Eu alloys formation. Then, electrochemical extractions using the two methodologies have been performed with extraction efficiency around 92% for copper electrode and 99.7% for co-reduction with aluminium ions.

  18. Solubilization of europium fulvate in aqueous solutions containing complexing agents

    Energy Technology Data Exchange (ETDEWEB)

    Legin, E.K.; Trifonov, Yu.I.; Khokhlov, M.L. [Khlopin Radium Inst., St. Petersburg (Russian Federation)] [and others

    1995-07-01

    The europium fulvate complex is synthesized and characterized by spectroscopic and chemical methods. By an example of this complex, it is demonstrated that metal complexes of humic substances are solubilized in the presence of complexing anions such as OAc{sup {minus}}, C{sub 2}O{sup 2{minus}}{sub 4}, and EDTA{sup 2{minus}}. The solubilization is studied by the optical and radioactive tracer methods. The solubilization of europium fulvate increases parallel to the complexing power of anions. In the solid fulvate europium is bonded stronger than in the ethylenediaminetetraacetate complex. The solubilization is considered as a potential source for decomposition of the {open_quotes}absorbing soil complex,{close_quotes} resulting in mobile forms of a metal and humic component in soils and soil waters.

  19. Excess europium content in Precambrian sedimentary rocks and continental evolution

    Science.gov (United States)

    Jakes, P.; Taylor, S. R.

    1974-01-01

    It is proposed that the europium excess in Precambrian sedimentary rocks, relative to those of younger age, is derived from volcanic rocks of ancient island arcs, which were the source materials for the sediments. Precambrian sedimentary rocks and present-day volcanic rocks of island arcs have similar REE patterns, total REE abundances, and excess Eu, relative to the North American shale composite. The present upper crustal REE pattern, as exemplified by that of sediments, is depleted in Eu, relative to chondrites. This depletion is considered to be a consequence of development of a granodioritic upper crust by partial melting in the lower crust, which selectively retains europium.

  20. Silicates in Alien Asteroids

    Science.gov (United States)

    2009-01-01

    This plot of data from NASA's Spitzer Space Telescopes shows that asteroid dust around a dead 'white dwarf' star contains silicates a common mineral on Earth. The data were taken primarily by Spitzer's infrared spectrograph, an instrument that breaks light apart into its basic constituents. The yellow dots show averaged data from the spectrograph, while the orange triangles show older data from Spitzer's infrared array camera. The white dwarf is called GD 40.

  1. Thermochemistry of Silicates

    Science.gov (United States)

    Costa, Gustavo; Jacobson, Nathan

    2015-01-01

    The thermodynamic properties of vapor and condensed phases of silicates are crucial in many fields of science. These quantities address fundamental questions on the formation, stability, transformation, and physical properties of silicate minerals and silicate coating compositions. Here the thermodynamic activities of silica and other species in solid solution have been measured by the analysis of the corresponding high temperature vapors using Knudsen Effusion Mass Spectrometry (KEMS). In first set of experiments KEMS has been used to examine the volatility sequence of species (Fe, SiO, Mg, O2 and O) present in the vapor phase during heating of fosterite-rich olivine (Fo93Fa7) up to 2400 C and to measure the Fe, SiO and Mg activities in its solid solution. The data of fosterite-rich olivine are essential for thermochemical equilibrium models to predict the atmospheric and surface composition of hot, rocky exoplanets (Lava Planets). In the second set of experiments the measured thermodynamic activities of the silica in Y2O3-SiO2 and Yb2O3-SiO2 systems are used to assess their reactivity and degradation recession as environmental barrier coatings (EBCs) in combustion environments (e.g. non-moveable parts of gas turbine engine).

  2. Murine High Specificity/Sensitivity Competitive Europium Insulin Autoantibody Assay

    Science.gov (United States)

    Babaya, Naru; Liu, Edwin; Miao, DongMei; Li, Marcella; Yu, Liping

    2009-01-01

    Abstract Background Most insulin autoantibody assays for both human and animal models are in a radioassay format utilizing 125I-insulin, but despite the radioassay format international workshops have documented difficulty in standardization between laboratories. There is thus a need for simpler assay formats that do not utilize radioactivity, yet retain the high specificity and sensitivity of radioassays. Methods To establish an easier enzyme-linked immunosorbent assay (ELISA) for insulin autoantibodies of non-obese diabetic (NOD) mice, we used an ELISA format, competition with unlabeled insulin, europium-avidin, and time-resolved fluorescence detection (competitive europium insulin autoantibody assay). Results The competitive europium assay of insulin autoantibodies when applied to sera from NOD mice had high sensitivity and specificity (92% sensitivity, 100% specificity) compared to our standard insulin autoantibody radioassay (72% sensitivity, 100% specificity) in analyzing blind workshop sera. It is noteworthy that though the assay has extremely high sensitivity for murine insulin autoantibodies and utilizes human insulin as target autoantigen, human sera with high levels of insulin autoantibodies are not detected. Conclusions Our results clearly indicate that low levels of insulin autoantibodies can be detected in an ELISA-like format. Combining a europium-based ELISA with competition with fluid-phase autoantigen can be applicable to many autoantigens to achieve high specificity and sensitivity in an ELISA format. PMID:19344197

  3. Tridentate benzimidazole-pyridine-tetrazolates as sensitizers of europium luminescence.

    Science.gov (United States)

    Shavaleev, Nail M; Eliseeva, Svetlana V; Scopelliti, Rosario; Bünzli, Jean-Claude G

    2014-05-19

    We report on new anionic tridentate benzimidazole-pyridine-tetrazolate ligands that form neutral 3:1 complexes with trivalent lanthanides. The ligands are UV-absorbing chromophores that sensitize the red luminescence of europium with energy-transfer efficiency of 74-100%. The lifetime and quantum yield of the sensitized europium luminescence increase from 0.5 ms and 12-13% for the as-prepared solids to 2.8 ms and 41% for dichloromethane solution. From analysis of the data, the as-prepared solids can be described as aqua-complexes [Ln(κ(3)-ligand)2(κ(1)-ligand)(H2O)x] where the coordinated water molecules are responsible for the strong quenching of the europium luminescence. In solution, the coordinated water molecules are replaced by the nitrogen atoms of the κ(1)-ligand to give anhydrous complexes [Ln(κ(3)-ligand)3] that exhibit efficient europium luminescence. X-ray structures of the anhydrous complexes confirm that the lanthanide ion (La(III), Eu(III)) is nine-coordinate in a distorted tricapped trigonal prismatic environment and that coordination of the lanthanide ion by tetrazolate is weaker than by carboxylate.

  4. Europium 2-benzofuranoate: Synthesis and use for bioimaging

    Science.gov (United States)

    Utochnikova, V. V.; Koshelev, D. S.; Medvedko, A. V.; Kalyakina, A. S.; Bushmarinov, I. S.; Grishko, A. Yu; Schepers, U.; Bräse, S.; Vatsadze, S. Z.

    2017-12-01

    Europium 2-benzofuranoate Eu(BFC)3(H2O)3 was successfully used for bioimaging in cellulo due to the combination of high solubility and high luminescence intensity in solution. It was possible due to the purposeful variation of the aromatic core of carboxylate anion.

  5. Luminescence studies on the europium doped strontium metasilicate phosphor prepared by solid state reaction method

    Directory of Open Access Journals (Sweden)

    Ishwar Prasad Sahu

    2017-03-01

    Full Text Available Europium doped strontium meta-silicate (namely SrSiO3:Eu3+ phosphor was prepared by a high temperature solid state reaction method. The sintered SrSiO3:Eu3+ phosphor possesses a monoclinic structure by the XRD. Energy dispersive X-ray spectrum (EDS confirms the presence of elements in the desired sample. Thermoluminescence (TL kinetic parameters such as activation energy (E, order of kinetics (b, and frequency factor (s were calculated by the peak shape method. The orange–red emission was shown to originate from the 5D0–7FJ (J = 0, 1, 2, 3, 4 transitions of Eu3+ ions as the sample was excited at 396 nm. The SrSiO3:Eu3+ phosphor with almost pure orange-red color purity (99.62% shows the quantum efficiency of 10.2% (excited by 396 nm, which is higher than those of commercial red phosphors Y2O3:Eu3+ and Y2O2S:Eu3+ with quantum efficiencies of 9.6% (excited by 394 nm and 4.2% (excited by 395 nm, respectively. Mechanoluminescence (ML intensity of the SrSiO3:Eu3+ phosphor was also found to increase linearly with increasing the impact velocity of the moving piston, suggesting that the discussed phosphor can be used as a stress sensor.

  6. SEPARATION OF EUROPIUM FROM OTHER LANTHANIDE RAE EARTHS BY SOLVENT EXTRACTION

    Science.gov (United States)

    Peppard, D.F.; Horwitz, E.P.; Mason, G.W.

    1963-02-12

    This patent deals with a process of separating europium from other lanthanides present in aqueous hydrochloric or sulfuric acid solutions. The europium is selectively reduced to the divalent state with a divalent chromium salt formed in situ from chromium(III) salt plus zinc amalgam. The other trivalent lanthanides are then extracted away from the divalent europium with a nitrogen-flushed phosphoric acid ester or a phosphonic acid ester. (AEC)

  7. Distribution, elimination, and renal effects of single oral doses of europium in rats.

    Science.gov (United States)

    Ohnishi, Keiko; Usuda, Kan; Nakayama, Shin; Sugiura, Yumiko; Kitamura, Yasuhiro; Kurita, Akihiro; Tsuda, Yuko; Kimura, Motoshi; Kono, Koichi

    2011-11-01

    Single doses of europium (III) chloride hexahydrate were orally administered to several groups of rats. Cumulative urine samples were taken at 0-24 h, and blood samples were drawn after 24-h administration. The europium concentration was determined in these samples by inductively coupled plasma atomic emission spectroscopy. The volume, creatinine, ß-2-microglobulin, and N-acetyl-ß-D-glucosaminidase were measured in the urine samples to evaluate possible europium-induced renal effects. The blood samples showed low europium distribution, with an average of 77.5 μg/L for all groups. Although the urinary concentration and excretion showed dose-dependent increases, the percentage of europium excreted showed a dose-dependent decrease, with an average of 0.31% in all groups. The administration of europium resulted in a significant decrease of creatinine and a significant increase of urinary volume, N-acetyl-ß-D-glucosaminidase, and ß-2-microglobulin. Rare earth elements, including europium, are believed to form colloidal conjugates that deposit in the reticuloendothelial system and glomeruli. This specific reaction may contribute to low europium bioavailability and renal function disturbances. Despite low bioavailability, the high performance of the analytical method for determination of europium makes the blood and urine sampling suitable tools for monitoring of exposure to this element. The results presented in this study will be of great importance in future studies on the health impacts of rare earth elements.

  8. [Synthesis and luminescence properties of reactive ternary europium complexes].

    Science.gov (United States)

    Guo, Dong-cai; Shu, Wan-gen; Zhang, Wei; Liu, You-nian; Zhou, Yue

    2004-09-01

    In this paper, five new reactive ternary europium complexes were synthesized with the first ligand of 1,10-phenanthroline and the reactive second ligands of maleic anhydride, acrylonitrile, undecenoic acid, oleic acid and linoleic acid, and also characterized by means of elemental analysis, EDTA titrimetric method, FTIR spectra and UV spectra. The fluorescence spectra show that the five new ternary complexes have much higher luminescence intensity than their corresponding binary complexes, and the synergy ability sequence of the five reactive ligands is as follows: linoleic acid > oleic acid > acrylonitrile > maleic anhydride > undecenoic acid. At the same time, the reactive ternary europium complexes coordinated with the reactive ligands, which can be copolymerized with other monomers, will provide a new way for the synthesis of bonding-type rare earth polymer functional materials with excellent luminescence properties.

  9. Solvent extraction of europium(III) to a fluorine-free ionic liquid phase with a diglycolamic acid extractant

    OpenAIRE

    Rout, Alok; Souza, Ernesto Rezende; Binnemans, Koen

    2014-01-01

    Europium(III) was extracted by bis(2-ethylhexyl)diglycolamic acid (DEHDGA) dissolved in the non-fluorinated ionic liquid tetraoctylammonium dodecyl sulphate, [N8888][DS]. The extraction behaviour of europium(III) was investigated as a function of various parameters: pH, extractant concentration, concentration of the europium(III) ion in the aqueous feed and concentration of the salting-out agent. A comparison was made with extraction of europium(III) by the acidic extractants bis(2-ethylhexyl...

  10. Silver lead borate glasses doped with europium ions for phosphors ...

    Indian Academy of Sciences (India)

    2017-07-25

    Jul 25, 2017 ... Abstract. Europium (Eu3+) doped silver lead borate glasses with the composition of xEu2O3−(1 − x)Ag2. O−29PbO−70B2O3 (x = 0, 0.1, 0.2, 0.3, 0.4 and 0.5 mol%) have been successfully prepared by conventional melt quenching method. Thermal, structural and luminescence properties have been studied ...

  11. Silver lead borate glasses doped with europium ions for phosphors ...

    Indian Academy of Sciences (India)

    Europium (Eu 3 + ) doped silver lead borate glasses with the composition of x Eu 2 O 3 −( 1 − x )Ag 2 O−29PbO−70B 2 O 3 ( x = 0 , 0.1, 0.2, 0.3, 0.4 and 0.5 mol%) have been successfully prepared by conventional meltquenching method. Thermal, structural and luminescence properties have been studied using ...

  12. Synthesis and luminescence properties for europium oxide nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Mo Zunli, E-mail: mozl@163.com [Key Laboratory of Eco-Environment-Related Polymer Materials, Ministry of Education of China, Key Laboratory of Polymer Materials of Gansu Province, College of Chemistry and Chemical Engineering, Northwest Normal University, Lanzhou 730070 (China) and State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi' an 710072 (China); Deng Zhepeng; Guo Ruibin [Key Laboratory of Eco-Environment-Related Polymer Materials, Ministry of Education of China, Key Laboratory of Polymer Materials of Gansu Province, College of Chemistry and Chemical Engineering, Northwest Normal University, Lanzhou 730070 (China); Fu Qiangang [State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi' an 710072 (China); Feng Chao; Liu Pengwei; Sun Yu [Key Laboratory of Eco-Environment-Related Polymer Materials, Ministry of Education of China, Key Laboratory of Polymer Materials of Gansu Province, College of Chemistry and Chemical Engineering, Northwest Normal University, Lanzhou 730070 (China)

    2012-01-25

    Highlights: Black-Right-Pointing-Pointer A novel high temperature sensitive fluorescent CNTs/Eu{sub 2}O{sub 3} nanocomposite was fabricated. Black-Right-Pointing-Pointer The nanocomposite showed strong fluorescent emission peaks at around 540 and 580 nm after calcined beyond 620 Degree-Sign C for 4 h. Black-Right-Pointing-Pointer The ultrahigh fluorescence intensity of the nanocomposites resulted from a synergetic effect of CNTs and europium oxide. Black-Right-Pointing-Pointer We also discovered that CNTs had an effect of fluorescence quenching. - Abstract: A novel high temperature sensitive fluorescent nanocomposite has been successfully synthesized by an economic hydrothermal method using carbon nanotubes (CNTs), europium oxide, and sodium dodecyl benzene sulfonate (SDBS). To our great interest, the nanocomposites show high temperature sensitivity after calcinations at various temperatures, suggesting a synergetic effect of CNTs and europium oxide which leads to ultrahigh fluorescence intensity of europium oxide nanotubes. When the novel high temperature sensitive fluorescent nanocomposites were calcined beyond 620 Degree-Sign C for 4 h, the obtained nanocomposites have a strong emission peak at around 540 and 580 nm, due to the {sup 5}D{sub 0} {yields} {sup 7}F{sub j} (j = 0, 1) forced electric dipole transition of Eu{sup 3+} ions. In turn, the emission spectra showed a slight blue shift. The intensity of this photoluminescence (PL) band is remarkably temperature-dependent and promotes strongly beyond 620 Degree-Sign C. This novel feature is attributed to the thermally activated carrier transfer process from nanocrystals and charged intrinsic defects states to Eu{sup 3+} energy levels. The novel high temperature sensitive fluorescent nanocomposite has potential applications in high temperature warning materials, sensors and field emission displays. It is also interesting to discover that CNTs have the effect of fluorescence quenching.

  13. Optical and magnetization studies on europium based iron pnictides

    Energy Technology Data Exchange (ETDEWEB)

    Zapf, Sina Maria Ute

    2015-07-01

    The investigations carried out in the framework of this thesis mainly concentrate on europium based iron pnictides. These are a peculiar member of the 122 family as they develop at low temperatures (∝20K) an additional magnetic order of the local rare earth moments. Therefore, europium based iron pnictides provide a unique platform to study the interplay of structural, magnetic and electronic effects in high-temperature superconductors. For this challenging purpose, we have employed SQUID magnetometry and Fourier-transform infrared spectroscopy on EuFe{sub 2}(As{sub 1-x}P{sub x}){sub 2} single crystals. By systematic studies of the in- and out-of-plane magnetic properties of a series of single crystals, we derived the complex magnetic phase diagram of europium based iron pnictides, which contains an A-type antiferromagnetic and a re-entrant spin glass phase. Furthermore, we have investigated the magneto-optical properties of EuFe{sub 2}As{sub 2}, revealing a much more complex magnetic detwinning process than expected. These studies demonstrate a remarkable interdependence between magnetic, electronic and structural effects that might be very important to understand the unconventional superconductivity in these fascinating materials.

  14. Use of europium ions for SAD phasing of lysozyme at the Cu Kα wavelength

    OpenAIRE

    Vijayakumar, Balakrishnan; Velmurugan, Devadasan

    2012-01-01

    Europium(III) ions bound to the surface of hen egg-white lysozyme were found to exhibit good anomalous signal facilitating SAD phasing using laboratory-source data and automated model building. The europium ion-binding sites were observed up to the 15σ level.

  15. Environmental silicate nano-biocomposites

    CERN Document Server

    Pollet, Eric

    2012-01-01

    Environmental Silicate Nano-Biocomposites focuses on nano-biocomposites, which are obtained by the association of silicates such as bioclays with biopolymers. By highlighting recent developments and findings, green and biodegradable nano-composites from both renewable and biodegradable polymers are explored. This includes coverage of potential markets such as packaging, agricultures, leisure and the fast food industry. The knowledge and experience of more than twenty international experts in diverse fields, from chemical and biochemical engineering to applications, is brought together in four different sections covering: Biodegradable polymers and Silicates, Clay/Polyesters Nano-biocomposites, Clay/Agropolymers Nano-biocomposites, and Applications and biodegradation of Nano-biocomposites. By exploring the relationships between the biopolymer structures, the processes, and the final properties Environmental Silicate Nano-Biocomposites explains how to design nano-materials to develop new, valuable, environmenta...

  16. Enhancement in red emission at room temperature from europium doped ZnO nanowires by 1,10 phenanthroline-europium interface induced resonant excitations

    Directory of Open Access Journals (Sweden)

    Soumen Dhara

    2017-02-01

    Full Text Available We show that europium doped ZnO nanowires after surface modification with organic ligand, 1,10 phenanthroline (phen leads to strong red emission at 613 nm which is a characteristic emission from the atomic levels of Eu3+. Surface modification with phen leads to formation of phenanthroline-europium interface on the surface of the nanowires due to attachment of Eu3+ ions. After an optimized surface modification with phen, intensity of both the UV emission (band edge and red emission improved by two orders of magnitude at room temperature. We observed multiple energy transfer pathways to the energy levels of Eu3+ ions through the phenanthroline-europium interface, which found to be very effective to the significant enhancement of emission from the dopant Eu3+. This study shows a new insight in to the energy transfer process from phen to the europium doped ZnO system.

  17. Optical properties and Judd–Ofelt analysis of Eu{sup 3+} activated calcium silicate

    Energy Technology Data Exchange (ETDEWEB)

    Barve, R.A., E-mail: rujuta_barve2003@yahoo.com; Suriyamurthy, N.; Panigrahi, B.S.; Venkatraman, B.

    2015-10-15

    Eu{sup 3+} activated calcium silicate was synthesized in stoichiometric ratio using the co-precipitation technique. The phosphors were characterized using X-ray diffraction and photoluminescence technique. Based on Judd–Ofelt (J–O) analysis, the intensity parameters Ω{sub 2} and Ω{sub 4} were calculated from the emission spectra for various Europium concentrations. The determined values indicate higher hypersensitive behavior of the {sup 5}D{sub 0}→{sup 7}F{sub 2} transition of Eu{sup 3+} ions in the host matrix and a stronger covalency. Different radiative properties have been discussed as the function of Eu{sup 3+} concentration. The lifetime decay pattern recorded for these samples indicated single exponential behavior. The quantum efficiency has been calculated to be 62% from the emission spectrum and the fluorescence lifetime was found to be 2.9 ms.

  18. Understanding silicate hydration from quantitative analyses of hydrating tricalcium silicates

    Science.gov (United States)

    Pustovgar, Elizaveta; Sangodkar, Rahul P.; Andreev, Andrey S.; Palacios, Marta; Chmelka, Bradley F.; Flatt, Robert J.; d'Espinose de Lacaillerie, Jean-Baptiste

    2016-01-01

    Silicate hydration is prevalent in natural and technological processes, such as, mineral weathering, glass alteration, zeolite syntheses and cement hydration. Tricalcium silicate (Ca3SiO5), the main constituent of Portland cement, is amongst the most reactive silicates in water. Despite its widespread industrial use, the reaction of Ca3SiO5 with water to form calcium-silicate-hydrates (C-S-H) still hosts many open questions. Here, we show that solid-state nuclear magnetic resonance measurements of 29Si-enriched triclinic Ca3SiO5 enable the quantitative monitoring of the hydration process in terms of transient local molecular composition, extent of silicate hydration and polymerization. This provides insights on the relative influence of surface hydroxylation and hydrate precipitation on the hydration rate. When the rate drops, the amount of hydroxylated Ca3SiO5 decreases, thus demonstrating the partial passivation of the surface during the deceleration stage. Moreover, the relative quantities of monomers, dimers, pentamers and octamers in the C-S-H structure are measured. PMID:27009966

  19. Dual doped graphene oxide for electrochemical sensing of europium ion

    Science.gov (United States)

    Kumar, Sunil; Patra, Santanu; Madhuri, Rashmi; Sharma, Prashant K.

    2017-05-01

    This present work represents a single step hydrothermal method for the preparation of N, and N, S dual doped graphene oxide (GO). First time, a comparative electrochemical study between single dope and dual doped GO was carried out using potassium ferrocyanide as an electro-active probe molecule and found that the dual doped GO has the highest electrocatalytic activity than single doped, due to the presence of two heteroatoms as a doping material. Afterwards, the dual doped GO was successfully applied for the electrochemical detection of a rare earth element i.e. europium, with LOD value of 5.92 μg L-1.

  20. Crystal growth of nanoscaled europium selenide having characteristic crystal shapes

    Energy Technology Data Exchange (ETDEWEB)

    Tanaka, Atsushi; Adachi, Taka-aki [Graduate School of Materials Science, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara 630-0192 (Japan); Hasegawa, Yasuchika, E-mail: hasegawa@ms.naist.j [Graduate School of Materials Science, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara 630-0192 (Japan); Kawai, Tsuyoshi [Graduate School of Materials Science, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara 630-0192 (Japan)

    2009-12-04

    Tetrapod-shaped EuSe nanocrystals were prepared through the thermal reduction of europium chloride an organic selenide complex, n-hexadecylamine, and two additives oleic acid and oleylamine. The obtained EuSe nanoparticles were characterized by X-ray diffraction (XRD). The crystal grain size from the XRD spectrum was estimated to be 50 nm. In contrast, observation of the transmission electron microscope (TEM) gave larger sized EuSe (average size: 200 nm). Anisotropic crystal-growth of EuSe nanocrystals was achieved by addition of a small amount of oleic acid in the crystal growth process.

  1. Final report on the safety assessment of aluminum silicate, calcium silicate, magnesium aluminum silicate, magnesium silicate, magnesium trisilicate, sodium magnesium silicate, zirconium silicate, attapulgite, bentonite, Fuller's earth, hectorite, kaolin, lithium magnesium silicate, lithium magnesium sodium silicate, montmorillonite, pyrophyllite, and zeolite.

    Science.gov (United States)

    Elmore, Amy R

    2003-01-01

    This report reviews the safety of Aluminum, Calcium, Lithium Magnesium, Lithium Magnesium Sodium, Magnesium Aluminum, Magnesium, Sodium Magnesium, and Zirconium Silicates, Magnesium Trisilicate, Attapulgite, Bentonite, Fuller's Earth, Hectorite, Kaolin, Montmorillonite, Pyrophyllite, and Zeolite as used in cosmetic formulations. The common aspect of all these claylike ingredients is that they contain silicon, oxygen, and one or more metals. Many silicates occur naturally and are mined; yet others are produced synthetically. Typical cosmetic uses of silicates include abrasive, opacifying agent, viscosity-increasing agent, anticaking agent, emulsion stabilizer, binder, and suspending agent. Clay silicates (silicates containing water in their structure) primarily function as adsorbents, opacifiers, and viscosity-increasing agents. Pyrophyllite is also used as a colorant. The International Agency for Research on Cancer has ruled Attapulgite fibers >5 microm as possibly carcinogenic to humans, but fibers Cosmetic Ingredient Review (CIR. The Cosmetic Ingredient Review (CIR) Expert Panel concluded that the extensive pulmonary damage in humans was the result of direct occupational inhalation of the dusts and noted that lesions seen in animals were affected by particle size, fiber length, and concentration. The Panel considers that most of the formulations are not respirable and of the preparations that are respirable, the concentration of the ingredient is very low. Even so, the Panel considered that any spray containing these solids should be formulated to minimize their inhalation. With this admonition to the cosmetics industry, the CIR Expert Panel concluded that these ingredients are safe as currently used in cosmetic formulations. The Panel did note that the cosmetic ingredient, Talc, is a hydrated magnesium silicate. Because it has a unique crystalline structure that differs from ingredients addressed in this safety assessment, Talc is not included in this report.

  2. Photoprotective properties of the fluorescent europium complex in UV-irradiated skin.

    Science.gov (United States)

    Vogt, O; Lademann, J; Rancan, F; Meinke, M C; Schanzer, S; Stockfleth, E; Sterry, W; Lange-Asschenfeldt, B

    2013-01-01

    In this study, we compared the UV-protective abilities of the europium complex compared to titanium dioxide, which represents the most common physical filter for ultraviolet light in the broad-band spectral range. The UV absorption and light transformative capacities of the europium complex were evaluated using a spectrometer with a double-integrating sphere showing that the europium complex does not only absorb and reflect UV light, but transforms it into red and infrared light. It was found that the europium complex binds to the surface of Jurkat cells in vitro. Cells incubated with the europium complex showed a significantly higher viability after UVA and UVB irradiation as compared to untreated cells and cells incubated with titanium dioxide pointing out its photoprotective properties. The europium complex and titanium dioxide show similar penetration capacities into the stratum corneum as tested in human and porcine skin using tape stripping analysis. The europium complex has proved to be an efficient UV filter with a low cyto- and phototoxic profile and therefore represents a potential candidate for use in sunscreen formulations. Copyright © 2013 S. Karger AG, Basel.

  3. NON-AUTOCLAVE SILICATE BRICK

    Directory of Open Access Journals (Sweden)

    V. N. Yaglov

    2015-01-01

    Full Text Available The paper proposes a technology for obtaining bricks on the basis of lime-silica mixtures where chemical interactions are practically completely realized in dispersive state at the stage of preparation of binding contact maturing and raw mixture as a whole. The role of forming operation (moulding is changed in principle because in this case conversion of dispersive system into a rock-like solid occurs and due to this the solid obtains complete water-resistance in contact with water immediately after forming operation. Theoretical basis for the developed technology is capability of silicate dispersive substances (hydrated calcium silicate to transit in non-stable state, to form a rock-like water-resistant solid in the moment of mechanical load application during forming process. Specific feature of the proposed method is an exclusion of additional operations for autoclaving of products from the process of obtaining a silicate brick.Synthetic hydrated calcium silicate in contrast to natural ones are more uniform in composition and structure, they contain less impurities and they are characterized by dispersive composition and due to the mentioned advantages they find wider practical application. Contact-condensation binders permit to manipulate product properties on their basis and ensure maximum correspondence to the requirements of the concrete application. Raw material sources for obtaining synthetic hydrated calcium silicates are practically un-limited because calcium-silicon containing substances are found as in various technogenic wastes so in natural compounds as well. So the problem for obtaining hydrated calcium silicates having contact-condensation ability for structure formation becomes more and more actual one. This transition is considered as dependent principally on arrangement rate of substance particles which determined the level of its instability.

  4. Low-voltage cathodoluminescence of europium-activated yttrium orthovanadate

    Energy Technology Data Exchange (ETDEWEB)

    Phillips, M.L.F.

    1995-03-01

    Emissive flat panel display systems operating in full color demand higher performance at low voltages (ca. 501000 V) from cathodoluminescent (CL) phosphors than cathode ray tubes require. Hydrothermal synthesis has been suggested as a route to phosphors with improved efficiencies, lower voltage thresholds, and increased saturation power. This hypothesis was tested in europium-doped yttrium orthovanadate (YVO{sub 4}:Eu), an efficient, red emitting CL phosphor. The CL efficiency of YVO{sub 4}:Eu crystallized from aqueous solution at 200{degrees}C is relatively low until it is annealed. The distribution of particle sizes in the low-temperature phosphor is similar to that in material made via a solid-state route, but crystallites remain much smaller (ca. 400 {Angstrom}) until they are annealed. These observations, along with the anomalously strong dependence of CL intensity on europium concentration, support a model in which efficiency principally depends on crystallite size. CL efficiency of both solid state and hydrothermal YVO{sub 4}:Eu increases with voltage at constant power. Surface-bound electrons are likely the dominant influence on efficiency at voltages near threshold. Saturation power is independent of synthetic route. It is apparent that the CL properties of hydrothermally synthesized YVO{sub 4}:Eu are essentially the same as those of YVO{sub 4}:Eu produced via conventional, high-temperature routes.

  5. In Vivo Toxicity Studies of Europium Hydroxide Nanorods in Mice

    Science.gov (United States)

    Patra, Chitta Ranjan; Abdel Moneim, Soha S.; Wang, Enfeng; Dutta, Shamit; Patra, Sujata; Eshed, Michal; Mukherjee, Priyabrata; Gedanken, Aharon; Shah, Vijay H; Mukhopadhyay, Debabrata

    2009-01-01

    Lanthanide nanoparticles and nanorods have been widely used for diagnostic and therapeutic applications in biomedical nanotechnology due to their fluorescence properties and pro-angiogenic to endothelial cells, respectively. Recently, we have demonstrated that europium (III) hydroxide [EuIII(OH)3] nanorods, synthesized by the microwave technique and characterized by several physico-chemical techniques, can be used as pro-angiogenic agents which introduce future therapeutic treatment strategies for severe ischemic heart/limb disease, and peripheral ischemic disease. The toxicity of these inorganic nanorods to endothelial cells was supported by several in vitro assays. To determine the in vivo toxicity, these nanorods were administered to mice through intraperitoneal injection (IP) everyday over a period of seven days in a dose dependent (1.25 to 125 mgKg−1day−1) and time dependent manner (8–60 days). Bio-distribution of europium elements in different organs was analyzed by inductively coupled plasma mass spectrometry (ICPMS). Short-term (S-T) and long-term (L-T) toxicity studies (mice sacrificed on day 8 and 60 for S-T and L-T, respectively) show normal blood hematology and serum clinical chemistry with the exception of a slight elevation of liver enzymes. Histological examination of nanorod treated vital organs (liver, kidney, spleen and lungs) showed no or only mild histological changes that indicate mild toxicity at the higher dose of nanorods. PMID:19616569

  6. Temperature dependences in electron-stimulated desorption of neutral europium

    CERN Document Server

    Ageev, V N; Madey, T E

    2003-01-01

    The electron-stimulated desorption (ESD) yield for neutral europium (Eu) atoms from Eu layers adsorbed on oxygen-covered tungsten surfaces has been measured as a function of electron energy, europium coverage and degree of oxidation of tungsten, with an emphasis on effects of substrate temperature. The measurements have been carried out using a time-of-flight method and surface ionization detector. We expand on an earlier report, and compare ESD of multivalent Eu with ESD of monovalent alkali atoms, studied previously. The Eu atom ESD is a complicated function of Eu coverage, electron energy and substrate temperature. In the coverage range 0.05-0.35 monolayer (ML), overlapping resonant-like Eu atom yield peaks are observed at electron energies E sub e of 36 and 41 eV that might be associated with Eu or W shallow core level excitations. Additional resonant-like peaks are seen at E sub e of 54 and 84 eV that are associated with W 5p and 5s level excitations. The Eu atom yield peaks at 36 and 41 eV are seen only...

  7. The Oxidation State of Europium in Halide Glasses

    Science.gov (United States)

    Weber, J.K.R.; Vu, M.; Paßlick, C.; Schweizer, S.; Brown, D.E.; Johnson, C.E.; Johnson, J.A.

    2012-01-01

    The luminescent properties of divalent europium ions can be exploited to produce storage phosphors for x-ray imaging applications. The relatively high cost and limited availability of divalent europium halides makes it desirable to synthesize them from the readily available trivalent salts. In this work, samples of pure EuCl3 and fluoride glass melts doped with EuCl3 were processed at 700-800 °C in an inert atmosphere furnace. The Eu oxidation state in the resulting materials was determined using fluorescence and Mössbauer spectroscopy. Heat treatment of pure EuCl3 for 10 minutes at 710 °C resulted in a material comprising approximately equal amounts of Eu2+ and Eu3+. Glasses made using mixtures of EuCl2 and EuCl3 in the starting material contained both oxidation states. This paper describes the sample preparation and analysis and discusses the results in the context of chemical equilibria in the melts. PMID:22101252

  8. Innovative triboluminescence study of multivitamin doped europium tetrakis

    Energy Technology Data Exchange (ETDEWEB)

    Fontenot, R.S. [Alabama A and M University, Department of Physics, Chemistry, and Mathematics, P.O. Box 1268, Normal, Alabama 35762 (United States); University of Louisiana at Lafayette, Department of Physics, P.O. Box 44210, Lafayette, LA 70504 (United States); Bhat, K.N.; Aggarwal, M.D. [Alabama A and M University, Department of Physics, Chemistry, and Mathematics, P.O. Box 1268, Normal, Alabama 35762 (United States); Hollerman, W.A. [University of Louisiana at Lafayette, Department of Physics, P.O. Box 44210, Lafayette, LA 70504 (United States)

    2012-05-15

    As the Space Shuttle program ends, NASA is developing the next generation of space vehicles. These new concept designs will require new and innovative structural health monitoring capabilities. One way to solve this problem is with smart impact sensors that use triboluminescent materials. In 2011, the authors reported an 82% increase in the triboluminescence yield of europium dibenzoylmethide triethylammonium (EuD{sub 4}TEA) by changing the starting material. It has been shown that introduction of dopants tends to enhance the triboluminescent light yield. Here we report the successful synthesis of a multivitamin doped europium tetrakis which appears to be spherical in shape. Inductively Coupled Plasma - Optical Emission Spectroscopy analysis showed the presence of 3.6% calcium, 0.62% magnesium, 0.1% iron, 0.01% copper and manganese. This new product has no shift in the triboluminescent or photoluminescent emission peaks, but only a change in the intensity. In addition, the doped EuD{sub 4}TEA powder statistically emits more triboluminescence while having the same decay time. (copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  9. Battery components employing a silicate binder

    Science.gov (United States)

    Delnick, Frank M [Albuquerque, NM; Reinhardt, Frederick W [Albuquerque, NM; Odinek, Judy G [Rio Rancho, NM

    2011-05-24

    A battery component structure employing inorganic-silicate binders. In some embodiments, casting or coating of components may be performed using aqueous slurries of silicates and electrode materials or separator materials.

  10. Submarine silicic volcanism: Processes and products

    Digital Repository Service at National Institute of Oceanography (India)

    Kalangutkar, N.G.; Iyer, S.D.

    The occurrence of submarine silicic volcanics is rare at the mid-oceanic ridges, abyssal depths, seamounts and fracture zones. Hydrothermal processes are active in submarine silicic environments and are associated with host ores of Cu, Au, Ag, Pb...

  11. Amended Silicated for Mercury Control

    Energy Technology Data Exchange (ETDEWEB)

    James Butz; Thomas Broderick; Craig Turchi

    2006-12-31

    Amended Silicates{trademark}, a powdered, noncarbon mercury-control sorbent, was tested at Duke Energy's Miami Fort Station, Unit 6 during the first quarter of 2006. Unit 6 is a 175-MW boiler with a cold-side electrostatic precipitator (ESP). The plant burns run-of-the-river eastern bituminous coal with typical ash contents ranging from 8-15% and sulfur contents from 1.6-2.6% on an as-received basis. The performance of the Amended Silicates sorbent was compared with that for powdered activated carbon (PAC). The trial began with a period of baseline monitoring during which no sorbent was injected. Sampling during this and subsequent periods indicated mercury capture by the native fly ash was less than 10%. After the baseline period, Amended Silicates sorbent was injected at several different ratios, followed by a 30-day trial at a fixed injection ratio of 5-6 lb/MMACF. After this period, PAC was injected to provide a comparison. Approximately 40% mercury control was achieved for both the Amended Silicates sorbent and PAC at injection ratios of 5-6 lbs/MMACF. Higher injection ratios did not achieve significantly increased removal. Similar removal efficiencies have been reported for PAC injection trials at other plants with cold-side ESPs, most notably for plants using medium to high sulfur coal. Sorbent injection did not detrimentally impact plant operations and testing confirmed that the use of Amended Silicates sorbent does not degrade fly ash quality (unlike PAC). The cost for mercury control using either PAC or Amended Silicates sorbent was estimated to be equivalent if fly ash sales are not a consideration. However, if the plant did sell fly ash, the effective cost for mercury control could more than double if those sales were no longer possible, due to lost by-product sales and additional cost for waste disposal. Accordingly, the use of Amended Silicates sorbent could reduce the overall cost of mercury control by 50% or more versus PAC for locations where

  12. Photoactive thin films of polycaprolactam doped with europium (III) complex using phenylalanine as ligand

    Energy Technology Data Exchange (ETDEWEB)

    Santos Garcia, Irene Teresinha, E-mail: irene@iq.ufrgs.br [Departamento de Fisico-Quimica, Instituto de Quimica, Universidade Federal do Rio Grande do Sul, Av. Bento Goncalves 9500, Bairro Agronomia, CEP 91501-970, Porto Alegre, RS (Brazil); Velleda Ribeiro, Patricia; Silva Correa, Diogo; Neto da Cunha, Igor Michel; Lenin Villarreal Carreno, Neftali [Instituto de Quimica e Geociencias, Universidade Federal de Pelotas, Campus Capao do Leao, s/n. CEP 96010-900, Pelotas, RS (Brazil); Ceretta Moreira, Eduardo [PPGEE, Universidade Federal do Pampa, Campus Bage, Bage- RS (Brazil); Severo Rodembusch, Fabiano [Departamento de Quimica Organica, Instituto de Quimica, Universidade Federal do Rio Grande do Sul, Av. Bento Goncalves 9500, Bairro Agronomia, CEP 91501-970, Porto Alegre, RS (Brazil)

    2011-12-01

    A photoactive complex based on europium(III) using the amino acid phenylalanine as ligand was prepared and characterized. The obtained europium(III)/phenylalanine complex presents an effective energy transfer from ligands to the rare earth center. The observed photoluminescent behavior for europium(III)/phenylalanine complex was similar to the well known europium(III)/ acetyl-{beta}-acetonate hydrate. New photoactive polyamide thin films were prepared using polycaprolactam as host of these complexes. The structural characterizations of the films were studied through Rutherford backscattering (RBS), Fourier transform infrared (FTIR) and Raman spectroscopies. The polyamide films doped with the amino acid and acetyl-{beta}-acetonate rare earth complexes maintain the original photoluminescent behavior, narrow emission bands corresponding to transitions {sup 5}D{sub 0} {yields} {sup 7}F{sub 0-4}, which indicates that this polymer is an excellent host to these complexes.

  13. Synthesis and luminescence properties of salicylaldehyde isonicotinoyl hydrazone derivatives and their europium complexes.

    Science.gov (United States)

    Shan, Wenfei; Liu, Fen; Liu, Jiang; Chen, Yanwen; Yang, Zehui; Guo, Dongcai

    2015-09-01

    Four novel salicylaldehyde isonicotinoyl hydrazone derivatives and their corresponding europium ion complexes were synthesized and characterized, while the luminescence properties and the fluorescence quantum yields of the target complexes were investigated. The results indicated that the ligands favored energy transfers to the emitting energy level of europium ion, and four target europium complexes showed the characteristic luminescence of central europium ion. Besides the luminescence intensity of the complex with methoxy group, which possessed the highest fluorescence quantum yield (0.522), was stronger than that of other complexes. Furthermore, the electrochemical properties of the target complexes were further investigated by cyclic voltammetry, the results indicated that the highest occupied molecular orbital (HOMO), lowest unoccupied molecular orbital (LUMO) energy levels and the oxidation potential of the complexes with electron donating group increased, however, that of the complexes with accepting electron group decreased. Copyright © 2015 Elsevier Inc. All rights reserved.

  14. [Synthesis and luminescence properties of ternary complexes of europium with aromatic carboxylic acid and acrylonitrile].

    Science.gov (United States)

    Guo, Dong-cai; Yi, Li-ming; Shu, Wan-gen; Zhang, Zhen-zhen; Zeng, Zhao-rong; Zhang, Xi-qian

    2006-11-01

    Five ternary complexes were synthesized from europium with aromatic carboxylic acid (p-methylbenzoic acid, methoxybenzoic acid, m-chlorobenzoic acid and benzoic acid, p-hydroxylbenzoic acid) and acrylonitrile, and characterized by means of elemental analysis, thermal analysis, FTIR spectra and UV spectra. The fluorescence spectra show that five ternary complexes have good luminescence properties, and the sequence of the ability of the aromatic carboxylic acids to transfer light energy to europium ion is as follows: p-methylbenzoic acid>benzoic acid>m-chlorobenzoic acid>p-hydroxylbenzoic acid>methoxybenzoic acid. Meanwhile, the ternary europium complexes containing a reactive ligand acrylonitrile will possibly have a potential application to the fabrication of bonding-type europium polymer luminescent materials.

  15. Optical characterization of europium-doped indium hydroxide nanocubes obtained by Microwave-Assisted Hydrothermal method

    OpenAIRE

    Motta, Fabiana Villela da; Marques,Ana Paula de Azevedo; Araújo,Vinícius Dantas de; Tavares, Mara Tatiane De Souza; Delmonte,Mauricio Roberto Bomio; Paskocimas, Carlos Alberto; Li, Máximo Siu; Nascimento, Rubens Maribondo do; Longo, Elson [UNESP

    2014-01-01

    Crystalline europium-doped indium hydroxide (In(OH)3:Eu) nanostructures were prepared by rapid and efficient Microwave-Assisted Hydrothermal (MAH) method. Nanostructures were obtained at low temperature. FE-SEM images confirm that these samples are composed of 3D nanostructures. XRD, optical diffuse reflectance and photoluminescence (PL) measurements were used to characterize the products. Emission spectra of europium-doped indium hydroxide (IH:xEu) samples under excitation (350.7 nm) present...

  16. Structural and optical properties of europium doped zirconia single crystals fibers grown by laser floating zone

    OpenAIRE

    Soares, M.R.N.; Nico, C.; Peres, M.; Ferreira, N.; Fernandes, A.J.S.; Monteiro, T.; COSTA, F.M.

    2011-01-01

    Yttria stabilized zirconia single crystal fibers doped with europium ions were developed envisaging optical applications. The laser floating zone technique was used in order to grow millimetric high quality single crystal fibers. The as-grown fibers are completely transparent and inclusion free, exhibiting a cubic structure. Under ultraviolet (UV) excitation, a broad emission band appears at 551 nm. The europium doped fibers are translucent with a tetragonal structure and exhibit an intense r...

  17. A non-aqueous reduction process for purifying ¹⁵³Gd produced in natural europium targets.

    Science.gov (United States)

    Johnsen, Amanda M; Soderquist, Chuck Z; McNamara, Bruce K; Fisher, Darrell R

    2013-12-01

    Gadolinium-153 is a low-energy gamma-emitter used in nuclear medicine imaging quality assurance. Produced in nuclear reactors using natural Eu₂O₃ targets, ¹⁵³Gd is radiochemically separated from europium isotopes by europium reduction. However, conventional aqueous europium reduction produces hydrogen gas, a flammability hazard in radiological hot cells. We altered the traditional reduction method, using methanol as the process solvent to nearly eliminate hydrogen gas production. This new, non-aqueous reduction process demonstrates greater than 98% europium removal and gadolinium yields of 90%. © 2013 Elsevier Ltd. All rights reserved.

  18. Intercalated europium metal in epitaxial graphene on SiC

    Science.gov (United States)

    Anderson, Nathaniel A.; Hupalo, Myron; Keavney, David; Tringides, Michael C.; Vaknin, David

    2017-10-01

    X-ray magnetic circular dichroism (XMCD) reveals the magnetic properties of intercalated europium metal under graphene on SiC(0001). The intercalation of Eu nanoclusters (average size 2.5 nm) between graphene and SiC substate are formed by deposition of Eu on epitaxially grown graphene that is subsequently annealed at various temperatures while keeping the integrity of the graphene layer. Using sum-rules analysis of the XMCD of Eu M4 ,5 edges at T =15 K, our samples show paramagnetic-like behavior with distinct anomaly at T ≈90 K, which may be related to the Nèel transition, TN=91 K, of bulk metal Eu. We find no evidence of ferromagnetism due to EuO or antiferromagnetism due to Eu2O3 , indicating that the graphene layer protects the intercalated metallic Eu against oxidation over months of exposure to atmospheric environment.

  19. Fluorescent lifetime imaging microscopy using Europium complexes improves atherosclerotic plaques discrimination.

    Science.gov (United States)

    Sicchieri, Letícia Bonfante; de Andrade Natal, Rodrigo; Courrol, Lilia Coronato

    2016-10-01

    The objective of this study is to characterize arterial tissue with and without atherosclerosis by fluorescence lifetime imaging microscopy (FLIM) using Europium Chlortetracycline complex (EuCTc) as fluorescent marker. For this study, twelve rabbits were randomly divided into a control group (CG) and an experimental group (EG), where they were fed a normal and hypercholesterolemic diet, respectively, and were treated for 60 days. Cryosections of the aortic arch specimens were cut in a vertical plane, mounted on glass slides, and stained with Europium (Eu), Chlortetracycline (CTc), Europium Chlortetracycline (EuCTc), and Europium Chlortetracycline Magnesium (EuCTcMg) solutions. FLIM images were obtained with excitation at 405 nm. The average autofluorescence lifetime within plaque depositions was ~1.36 ns. Reduced plaque autofluorescence lifetimes of 0.23 and 0.31 ns were observed on incubation with EuCTc and EuCTcMg respectively. It was observed a quenching of collagen, cholesterol and TG emission spectra increasing EuCTc concentration. The drastic reduction in fluorescence lifetimes is due to a resonant energy transfer between collagen, triglycerides, cholesterol and europium complexes, quenching fluorescence.

  20. Visible-light sensitized luminescent europium(III)-β-diketonate complexes: bioprobes for cellular imaging.

    Science.gov (United States)

    Reddy, M L P; Divya, V; Pavithran, Rani

    2013-11-21

    Visible-light sensitized luminescent europium(III) molecular materials are of considerable importance because their outstanding photophysical properties make them well suited as labels in fluorescence-based bioassays and low-voltage driven pure red-emitters in optoelectronic technology. One challenge in this field is development of visible-light sensitizing ligands that can form highly emissive europium(III) complexes with sufficient stability and aqueous solubility for practical applications. Indeed, some of the recent reports have demonstrated that the excitation-window can be shifted to longer-wavelengths in europium(III)-β-diketonate complexes by appropriate molecular engineering and suitably expanded π-conjugation in the complex molecules. In this review, attention is focused on the latest innovations in the syntheses and photophysical properties of visible-light sensitized europium(III)-β-diketonate complexes and their application as bioprobes for cellular imaging. Furthermore, luminescent nanomaterials derived from long-wavelength sensitized europium(III)-β-diketonate complexes and their application in life sciences are also highlighted.

  1. The electronic properties of mixed valence hydrated europium chloride thin film.

    Science.gov (United States)

    Silly, M G; Charra, F; Lux, F; Lemercier, G; Sirotti, F

    2015-07-28

    We investigate the electronic properties of a model mixed-valence hydrated chloride europium salt by means of high resolution photoemission spectroscopy (HRPES) and resonant photoemission spectroscopy (RESPES) at the Eu 3d → 4f and 4d → 4f transitions. From the HRPES spectra, we have determined that the two europium oxidation states are homogeneously distributed in the bulk and that the hydrated salt film is exempt from surface mixed valence transition. From the RESPES spectra, the well separated resonant contributions characteristic of divalent and trivalent europium species (4f(6) and 4f(7) final states, respectively) are accurately extracted and quantitatively determined from the resonant features measured at the two edges. The partial absorption yield spectra, obtained by integrating the photoemission intensity in the valence-band region, can be well reproduced by atomic multiplet calculation at the M(4,5) (3d-4f) absorption edge and by an asymmetric Fano-like shape profile at the N(4,5) (4d-4f) absorption edge. The ratio of Eu(2+) and Eu(3+) species measured at the two absorption edges matches with the composition of the mixed valence europium salt as determined chemically. We have demonstrated that the observed spectroscopic features of the mixed valence salt are attributed to the mixed-valence ground state rather than surface valence transition. HRPES and RESPES spectra provide reference spectra for the study of europium salts and their derivatives.

  2. Tailoring polymer properties with layered silicates

    Science.gov (United States)

    Xu, Liang

    Polymer layered silicate nanocomposites have found widespread applications in areas such as plastics, oil and gas production, biomedical, automotive and information storage, but their successful commercialization critically depends on consistent control over issues such as complete dispersion of layered silicate into the host polymer and optimal interaction between the layered silicates and the polymers. Polypropylene is a commercially important polymer but usually forms intercalated structures with organically modified layered silicate upon mixing, even it is pre-treated with compatibilizing agent such as maleic anhydride. In this work, layered silicate is well dispersed in ammonium modified polypropylene but does not provide sufficient reinforcement to the host polymer due to poor interactions. On the other hand, interactions between maleic anhydride modified polypropylene and layered silicate are fine tuned by using a small amount of maleic anhydride and mechanical strength of the resultant nanocomposites are significantly enhanced. In particular, the melt rheological properties of layered silicate nanocomposites with maleic anhydride functionalized polypropylene are contrasted to those based on ammonium-terminated polypropylene. While the maleic anhydride treated polypropylene based nanocomposites exhibit solid-like linear dynamic behavior, consistent with the formation of a long-lived percolated nanoparticle network, the single-end ammonium functionalized polypropylene based nanocomposites demonstrated liquid-like behavior at comparable montmorillonite concentrations. The differences in the linear viscoelasticity are attributed to the presence of bridging interaction in maleic anhydride functionalized nanocomposites, which facilitates formation of a long-lived silicate network mediated by physisorbed polymer chains. Further, the transient shear stress of the maleic anhydride functionalized nanocomposites in start-up of steady shear is a function of the shear

  3. Europium-doped calcium titanate: Optical and structural evaluations

    Energy Technology Data Exchange (ETDEWEB)

    Mazzo, Tatiana Martelli; Pinatti, Ivo Mateus [INCTMN, LIEC, Departamento de Química, Universidade Federal de São Carlos, P.O. Box 676, 13565-905 São Carlos, SP (Brazil); Macario, Leilane Roberta [INCTMN, LIEC, Instituto de Química, Universidade Estadual Paulista, P.O. Box 355, 14800-900 Araraquara, SP (Brazil); Avansi, Waldir [Centro de Ciências Exatas e de Tecnologia, Departamento de Física, Universidade Federal de São Carlos, Jardim Guanabara, 13565-905 São Carlos, SP (Brazil); Moreira, Mario Lucio [Instituto de Física e Matemática, Universidade Federal de Pelotas, P.O. Box 354, Campus do Capão do Leão, 96001-970 Pelotas, RS (Brazil); Rosa, Ieda Lucia Viana, E-mail: ilvrosa@ufscar.br [INCTMN, LIEC, Departamento de Química, Universidade Federal de São Carlos, P.O. Box 676, 13565-905 São Carlos, SP (Brazil); Mastelaro, Valmor Roberto [Instituto de Física de São Carlos, Departamento de Física e Ciência dos Materiais, Universidade de São Paulo, P.O. Box 369, Av Trabalhador São Carlense 400, 13560-970 São Carlos, SP (Brazil); Varela, José Arana; Longo, Elson [INCTMN, LIEC, Instituto de Química, Universidade Estadual Paulista, P.O. Box 355, 14800-900 Araraquara, SP (Brazil)

    2014-02-05

    Highlights: • CaTiO{sub 3}:Eu{sup 3+} were obtained using low temperatures and very short reactional times. • The Eu{sup 3+} changes the local order–disorder of the [TiO{sub 6}] and [CaO{sub 12}] clusters. • Lifetime decay curves reveal two sites of symmetry of the Eu{sup 3+} in the CT matrix. • CaTiO{sub 3}:Eu{sup 3+} exhibit the strongest luminescent intensity and pure red color. -- Abstract: Pure Calcium Titanate (CT-pure) and Europium doped Calcium Titanate Ca{sub 1−x}Eu{sub x}TiO{sub 3} (x = 0.5%, 1.0% and 2.0% molar ratio of Eu{sup 3+} ions) powders were synthesized by hydrothermal microwave method (HTMW) at 140 °C for 8 min. The HTMW method appears to be an efficient method to prepare the luminescence materials using low temperatures and very short reactional times. In addition it is possible to determine specific correlations imposed by TiCl{sub 4} replacement by titanium isopropoxide [Ti(OC{sub 3}H{sub 7}){sub 4}] changing the reaction character and resulting in two different options of europium doping CT syntesis. To evaluate the influence of the structural order–disorder among the reactions and different properties of these materials, the following techniques were used for characterization. XANES spectroscopy that revealed that the introduction of Eu{sup 3+} ions into the CT lattice induces to significant changes in the local order–disorder around both, [TiO{sub 6}] and [CaO{sub 12}], complex clusters. PL spectra show Eu{sup 3+} emission lines ascribed to the Eu{sup 3+} transitions from {sup 5}D{sub 0} excited states to {sup 7}F{sub J} (J = 0, 1–4) fundamental states in CT:Eu{sup 3+} powders excited at 350 and 394 nm.

  4. Nanoscale zinc silicate from phytoliths

    Science.gov (United States)

    Qadri, S. B.; Gorzkowski, E. P.; Rath, B. B.; Feng, C. R.; Amarasinghe, R.; Freitas, J. A.; Culbertson, J. C.; Wollmershauser, J. A.

    2017-10-01

    We report a faster, less expensive method of producing zinc silicate nanoparticles. Such particles are used in high volume to make phosphors and anti-corrosion coatings. The approach makes use of phytoliths (plant rocks), which are microscopic, amorphous, and largely silicate particles embedded in plants, that lend themselves to being easily broken down into nanoparticles. Nanoparticles of Zn2SiO4 were produced in a two stage process. In the refinement stage, plant residue, mixed with an appropriate amount of ZnO, was heated in an argon atmosphere to a temperature exceeding 1400 °C for four to six hours and then heated in air at 650 °C to remove excess carbon. TEM shows 50-100 nm nanoparticles. Raman scattering indicates that only the -Zn2SiO4 crystalline phase was present. X-ray analysis indicated pure rhombohedral R 3 bar phase results from using rice/wheat husks. Both samples luminesced predominantly at 523 nm when illuminated with X-rays or UV laser light.

  5. RBS and RNRA studies on sorption of europium by apatite

    Energy Technology Data Exchange (ETDEWEB)

    Ohnuki, Toshihiko; Kozai, Naofumi; Isobe, Hiroshi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Murakami, Takashi; Yamamoto, Shunya; Aoki, Yasushi; Naramoto, Hiroshi

    1997-03-01

    The sorption mechanism of europium, alternative of trivalent TRU has been studied based on the depth profiles of elements obtained by Rutherford Backscattering Spectroscopy (RBS) and Resonant Nuclear Reaction Analysis (RNRA). The positive peak for Eu and the negative peak for Ca were observed in the subtracted RBS spectra of the apatites on which Eu was sorbed from that of the fresh apatite. This indicates that Eu was sorbed on apatite, while a fraction of Ca was released from apatite. The peak height for Eu in the RBS spectrum of the apatite obtained at 75degC was higher than that of the apatite at 40degC. The depth profile of hydrogen of the apatite on which Eu was sorbed was similar to that of the fresh apatite. The concentration of Eu in the solution decreased with increasing temperature. On the contrary, the concentration of Ca increased with increasing temperature. Thus, it is concluded that a fraction of Eu is exchanged for Ca in the structure of apatite. (author)

  6. Spectrofluorimetric determination of heparin using doxycycline-europium probe

    Energy Technology Data Exchange (ETDEWEB)

    Li Jing [Department of Chemistry, Shandong Normal University, Jinan 250014 (China); Liu Jinkai [Department of Chemistry, Shandong Normal University, Jinan 250014 (China); Zhu Xiaojing [Department of Chemistry, Shandong Normal University, Jinan 250014 (China); Peng Qian [Department of Chemistry, Shandong Normal University, Jinan 250014 (China); Jiang Chongqiu [Department of Chemistry, Shandong Normal University, Jinan 250014 (China)]. E-mail: jiangchongqiu@sdnu.edu.cn

    2005-06-15

    A new spectrofluorimetric method was developed for the determination of the trace amount of heparin (Hep). Using doxycycline (DC)-europium ion (Eu{sup 3+}) as a fluorescent probe, in the buffer solution of pH=8.9, Hep can remarkably enhance the fluorescence intensity of the DC-Eu{sup 3+} complex at {lambda}=612 nm and the enhanced fluorescence intensity of Eu{sup 3+} ion is in proportion to the concentration of Hep. Optimum conditions for the determination of Hep were also investigated. The linear range and detection limit for the determination of Hep are 0.04-0.8 {mu}g/mL and 19.7 ng/mL, respectively. This method is simple, practical, and relatively free of interference from coexisting substances and can be successfully applied to assess Hep in biological samples. By the Rosenthal graphic method, the association constant and binding numbers of Hep with the probe are 6.60x10{sup 4} L/mol and 33.9. Moreover, the enhancement mechanism of the fluorescence intensity in the DC-Eu{sup 3+} system and the DC-Eu{sup 3+}-Hep-CTMAB system have been also discussed.

  7. Extraction of americium and europium by CMPO-substituted adamantylcalixarenes

    Energy Technology Data Exchange (ETDEWEB)

    Babain, V.A.; Alyapyshev, M.Yu.; Karavan, M.D. [V.G. Khlopin Radium Inst., St. Petersburg (Russian Federation); Boehmer, V.; Wang, L. [Johannes Guttenberg Univ., Mainz (Germany); Shokova, E.A.; Motornaya, A.E.; Vatsouro, I.M.; Kovalev, V.V. [M. V. Lomonosov Moscow State Univ., Moscow (Russian Federation)

    2005-07-01

    Eight p-adamantylcalix[4]arene derivatives, bearing four CMPO-like functions [-(CH{sub 2}){sub n}-NH-C(O)-CH{sub 2-}P(O)Ph{sub 2}] at the wide (4a,b, n = 0, 1) or narrow (5a-c and 6a-c, n = 2-4) rims were synthesized for the first time. Studies of the extraction of americium(III) and europium(III) from 3 M HNO{sub 3} solutions to organic phases (dichloromethane, m-nitro-trifluoromethylbenzene) showed: (i) The extraction ability for all the adamantylcalixarene ligands is much better than for their monomeric analogues -N-(1-adamantyl)-, N-(1-adamantylmethyl)- and N,N-(dibutyl)carbamoylmethyldiphenylphosphine oxides 7a, 7b, 8; (ii) The extraction percentage increases strongly with increasing length of the spacer for all types of ligands 4-6, and best extraction results were found for 4b (n = 1) and 5c (n = 4); (iii) The separation coefficient D{sub Am}/D{sub Eu} for the investigated compounds did not exceed 2, which is close to the narrow rim CMPO calixarenes, studied earlier; (iv) Variation of the spacer length between CMPO groups attached to the 1,3- and 2,4-positions of the calixarene platform in 6 did not lead to appreciably improved extractants, neither with respect to the extraction abilities (D) nor to the selectivities (D{sub Am}/D{sub Eu}). (orig.)

  8. Preparation of europium-labelled DNA probes and their properties.

    Science.gov (United States)

    Hurskainen, P; Dahlén, P; Ylikoski, J; Kwiatkowski, M; Siitari, H; Lövgren, T

    1991-01-01

    A chemical method for labelling DNA with a europium chelate is presented. First, primary aliphatic amino groups are introduced onto DNA in a transamination reaction. The transamination reaction is altered by adjusting temperature and duration of the reaction. Subsequently, the modified DNA is reacted with an isothiocyanate derivative of a Eu chelate. The optimum amount of Eu chelates on a DNA probe is 4-8% of total nucleotides. There is a decrease of 0.7 degrees C in the melting temperature of DNA for each incorporated Eu chelate on 100 bases. Hybridization efficiency is lowered by the introduction of Eu chelates but this effect can be partly overcome by using high DNA probe concentrations. The detection limit of the Eu-labelled probe is 0.15 attomoles of target DNA in a mixed-phase hybridization assay on microtitration wells. In addition to high sensitivity the Eu-labelled probes offer convenience in use and results which are quantitative and easy to interpret. PMID:1826948

  9. Chloride, bromide and iodide scintillators with europium doping

    Science.gov (United States)

    Zhuravleva, Mariya; Yang, Kan

    2014-08-26

    A halide scintillator material is disclosed where the halide may comprise chloride, bromide or iodide. The material is single-crystalline and has a composition of the general formula ABX.sub.3 where A is an alkali, B is an alkali earth and X is a halide which general composition was investigated. In particular, crystals of the formula ACa.sub.1-yEu.sub.yI.sub.3 where A=K, Rb and Cs were formed as well as crystals of the formula CsA.sub.1-yEu.sub.yX.sub.3 (where A=Ca, Sr, Ba, or a combination thereof and X=Cl, Br or I or a combination thereof) with divalent Europium doping where 0.ltoreq.y.ltoreq.1, and more particularly Eu doping has been studied at one to ten mol %. The disclosed scintillator materials are suitable for making scintillation detectors used in applications such as medical imaging and homeland security.

  10. Spectrofluorimetric determination of lecithin using a tetracycline-europium probe

    Energy Technology Data Exchange (ETDEWEB)

    Wang Ting [Department of Chemistry, Shandong Normal University, Jinan, Shandong 250014 (China); Jiang Chongqiu [Department of Chemistry, Shandong Normal University, Jinan, Shandong 250014 (China)]. E-mail: jiangchongqiu@sdnu.edu.cn

    2006-03-02

    Trace amount of lecithin (PC) was determined in the buffer solution of pH 5.7, using tetracycline (TC)-europium ion (Eu{sup 3+}) as a fluorescent probe. PC can remarkably enhance the fluorescence intensity of the TC-Eu{sup 3+} complex at {lambda} = 612 nm and the enhanced fluorescence intensity of Eu{sup 3+} is in proportion to the concentration of PC. Optimum conditions for the determination of PC were also investigated. The linear range and detection limit for the determination of PC are 4.0 x 10{sup -7} to 1.4 x 10{sup -5} mol/L and 3.9 x 10{sup -8} mol/L. This method is simple, practical and relatively free of interference from coexisting substances and can be successfully applied to assess PC in serum samples. Moreover, the enhancement mechanism of the fluorescence intensity in the TC-Eu{sup 3+} system, the TC-Eu{sup 3+}-PC system, and the TC-Eu{sup 3+}-PC-sodium dodecyl benzene sulfonate (SDS) system is also discussed.

  11. Artifacts in the determination of the binding of americium and europium to an aquatic fulvic acid

    Energy Technology Data Exchange (ETDEWEB)

    Lead, J.R.; Hamilton-Taylor, J.; Kelly, M. [Institute of Environmental and Biological Sciences, Lancaster University, Lancaster (United Kingdom)

    1995-11-23

    The binding of europium and americium by an aquatic fulvic acid was investigated using an equilibrium ion exchange technique (Schubert`s method). The results for europium were consistent with literature data. Americium gave anomalous results for both the D{sub o} values (partition coefficient of the metal between the resin and solution phases in the absence of the fulvic acid) and D values (partition coefficient of the metal between the resin and solution phases in the presence of the fulvic acid). The values for americium were unexpectedly low and, in the case of D values, only slightly pH dependent. The cause of the discrepancy was found to be the partial dissolution of the resin or the loss of small colloidal material from the resin. The effects on the europium results were minimal due to the use of lower resin weights and higher metal concentrations

  12. Synthesis and luminescence properties of 2-(benzylcarbamoyl)phenyl derivatives and their europium complexes.

    Science.gov (United States)

    Guo, Dongcai; He, Wei; Liu, Bang; Gou, Lining; Li, Ruixia

    2013-01-01

    Six novel 2-(benzylcarbamoyl)phenyl derivatives were synthesized and characterized by (1) H-NMR, mass spectrometry, infrared spectra and elemental analysis. Their europium complexes were prepared and characterized by elemental analysis, EDTA titrimetric analysis, IR and UV spectra as well as molar conductivity measurements. The luminescence properties of these complexes were investigated and results show that 2-(benzylcarbamoyl)phenyl derivatives possess high selectivity and good coordination with the europium ion. Complex Eu-2-(benzylcarbamoyl)phenyl-2-phenylacetate showed green luminescence that was emitted by the ligand of 2-(benzylcarbamoyl)phenyl-2-phenylacetate, while other complexes showed the characteristic red luminescence of europium ion and also possessed high luminescence intensity. Copyright © 2012 John Wiley & Sons, Ltd.

  13. Induction of Circularly Polarized Luminescence from Europium by Amino Acid Based Ionic Liquids.

    Science.gov (United States)

    Zercher, Ben; Hopkins, Todd A

    2016-11-07

    Materials that emit circularly polarized light have application in several important industries. Because they show large optical activity and emit sharp visible light transitions, europium complexes are often exploited in applications that require circularly polarized luminescence (CPL). Chiral and coordinating ionic liquids based on prolinate, valinate, and aspartate anions are used to induce CPL from a simple achiral europium triflate salt. The sign of the induced CPL is dependent on the handedness (l vs d) of the amino acid anion. Comparison of the CPL spectra in ionic liquid with proline and valine vs aspartate shows that the number of carboxylate groups in the amino acid anion influences the europium coordination environment. DFT calculations predict a chiral eight-coordinate Eu(Pro)4- structure in the prolinate ionic liquid and a chiral seven- or eight-coordinate Eu(Asp)33- structure in the aspartate ionic liquid.

  14. Comparative analysis of conjugated alkynyl chromophore-triazacyclononane ligands for sensitized emission of europium and terbium.

    Science.gov (United States)

    Soulié, Marine; Latzko, Frédéric; Bourrier, Emmanuel; Placide, Virginie; Butler, Stephen J; Pal, Robert; Walton, James W; Baldeck, Patrice L; Le Guennic, Boris; Andraud, Chantal; Zwier, Jurriaan M; Lamarque, Laurent; Parker, David; Maury, Olivier

    2014-07-07

    A series of europium and terbium complexes based on a functionalized triazacyclononane carboxylate or phosphinate macrocyclic ligand is described. The influence of the anionic group, that is, carboxylate, methylphosphinate, or phenylphosphinate, on the photophysical properties was studied and rationalized on the basis of DFT calculated structures. The nature, number, and position of electron-donating or electron-withdrawing aryl substituents were varied systematically within the same phenylethynyl scaffold in order to optimize the brightness of the corresponding europium complexes and investigate their two-photon absorption properties. Finally, the europium complexes were examined in cell-imaging applications, and selected terbium complexes were studied as potential oxygen sensors. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Magnetic and structural properties of yellow europium oxide compound and Eu(OH){sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Dongwook, E-mail: dongwookleedl324@gmail.com [Cavendish Laboratory, University of Cambridge, J. J Thomson Av., Cambridge CB3 0HE (United Kingdom); Seo, Jiwon, E-mail: jiwonseo@yonsei.ac.kr [Department of Physics and IPAP, Yonsei University, Seoul 120-749 (Korea, Republic of); Valladares, Luis de los Santos [Cavendish Laboratory, University of Cambridge, J. J Thomson Av., Cambridge CB3 0HE (United Kingdom); Avalos Quispe, O. [Laboratorio de Cerámicos y Nanomateriales, Facultad de Ciencias Físicas, Universidad Nacional Mayor de San Marcos, Ap. Postal 14-0149, Lima, Perú (Peru); Barnes, Crispin H.W. [Cavendish Laboratory, University of Cambridge, J. J Thomson Av., Cambridge CB3 0HE (United Kingdom)

    2015-08-15

    A new material based on a yellow europium oxide compound was prepared from europium oxide in a high vacuum environment. The structural and magnetic properties of the material were investigated. Owing to the absence of a crystal structure, the material exhibited a disordered magnetic behavior. In a reaction with deionized (DI) water without applied heat, the compound assumed a white color as soon as the DI water reached the powder, and the structure became polycrystalline Eu(OH){sub 3}. The magnetic properties, such as the thermal hysteresis, disappeared after the reaction with DI water, and the magnetic susceptibility of the yellow oxide compound weakened. The magnetic properties of Eu(OH){sub 3} were also examined. Although Eu{sup 3+} is present in Eu(OH){sub 3}, a high magnetic moment due to the crystal field effect was observed. - Graphical abstract: (top left) Optical image of the yellow europium oxide compound. (top right) Optical image of the product of DI water and yellow europium oxide. (bottom) Magnetization curves as a function of temperature measured in various magnetic field. - Highlights: • We prepared a new material based on a yellow europium oxide compound from europium oxide. • We characterized the magnetic properties of the material which exhibits a disordered magnetic behavior such as thermal hysteresis. • The compound turned white (Eu(OH){sub 3}) as soon as the DI water reached the powder. • The thermal hysteresis disappeared after the reaction with DI water and the magnetic susceptibility of the yellow oxide compound weakened.

  16. Europium stearate additives delay oxidation of UHMWPE for orthopaedic applications: a pilot study.

    Science.gov (United States)

    Gallardo, Luis A; Carpentieri, Ilenia; Laurent, Michel P; Costa, Luigi; Wimmer, Markus A

    2011-08-01

    Ultrahigh-molecular-weight polyethylene (UHMWPE) is used as an articulating surface in prosthetic devices. Its failure under various mechanisms after oxidation is of utmost concern. Free radicals formed during the sterilization process using high-energy irradiation result in oxidation. Europium, an element of the lanthanide family, has a unique electron configuration with an unusual lack of preference for directional bonding and notable bonding to oxygen. Because of this, it currently is used in studies for stabilization of polymers such as polyvinyl chloride. We asked whether europium stearate could enhance the oxidation resistance after irradiation in nitrogen of UHMWPE. Conventional nonirradiated and gamma-irradiated in nitrogen UHMWPE were compared with polyethylene doped with 375 ppm and 3750 ppm europium(III) stearate under the same treatment conditions. Chemical characterization was performed by Fourier transform infrared (FTIR) microspectroscopy using 200-μm thin films. The oxidation of doped samples with time was compared with that of conventional samples using accelerated oven aging. The types of oxidation products were identified by FTIR and quantified per material and treatment condition as indications of the oxidation level and mechanism. The generation rate of hydroperoxides and ketones was decelerated proportionally with concentration of europium stearates. The oxidative mechanism appeared similar to that of conventional polyethylene with the same types of measurable end products as ketones and hydroperoxides. Yet, the rate of generation of the latter appeared to be slowed down by the action of europium stearate. Europium stearate mixed in UHMWPE decelerated the oxidation reactions triggered by gamma irradiation in nitrogen, seemingly without major alteration of the oxidation mechanism.

  17. Silicates materials of high vacuum technology

    CERN Document Server

    Espe, Werner

    2013-01-01

    Materials of High Vacuum Technology, Volume 2: Silicates covers silicate insulators of special importance to vacuum technology. The book discusses the manufacture, composition, and physical and chemical properties of technical glasses, quartz glass, quartzware, vycor glass, ceramic materials, mica, and asbestos.

  18. Temperature dependent luminescence of a europium complex incorporated in poly(methyl methacrylate).

    Science.gov (United States)

    Liang, Hao; Xie, Fang; Ren, Xiaojun; Chen, Yifa; Chen, Biao; Guo, Fuquan

    2013-12-01

    An europium β-diketonate complex with a dipyrazolyltriazine derivative ligand, Eu(TTA)3DPBT, has been incorporated into poly(methyl methacryate) (PMMA). The influence of temperature on its luminescence properties has been investigated. The fluorescence emission spectra and luminescence lifetimes showed temperature sensitivity. The analysis of the relative intensity ratio (R) of (5)D0 → (7)F2 to (5)D0 → (7)F1 transition and Judd-Ofelt experimental intensity parameters Ω2 indicated that the local structure and asymmetry in the vicinity of europium ions show no obvious change when the temperature is increased. Copyright © 2013 Elsevier B.V. All rights reserved.

  19. Mesoporous Silicate Materials in Sensing

    Directory of Open Access Journals (Sweden)

    Paul T. Charles

    2008-08-01

    Full Text Available Mesoporous silicas, especially those exhibiting ordered pore systems and uniform pore diameters, have shown great potential for sensing applications in recent years. Morphological control grants them versatility in the method of deployment whether as bulk powders, monoliths, thin films, or embedded in coatings. High surface areas and pore sizes greater than 2 nm make them effective as adsorbent coatings for humidity sensors. The pore networks also provide the potential for immobilization of enzymes within the materials. Functionalization of materials by silane grafting or through cocondensation of silicate precursors can be used to provide mesoporous materials with a variety of fluorescent probes as well as surface properties that aid in selective detection of specific analytes. This review will illustrate how mesoporous silicas have been applied to sensing changes in relative humidity, changes in pH, metal cations, toxic industrial compounds, volatile organic compounds, small molecules and ions, nitroenergetic compounds, and biologically relevant molecules.

  20. Study of the europium behavior in aqueous media; Estudio sobre el comportamiento del europio en medios acuosos

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez R, E.; Jimenez R, M.; Solache R, M.; Martinez M, V. [Instituto Nacional de Investigaciones Nucleares, Departamento de Quimica, A.P. 18-1027, C.P. 11801 Mexico D.F. (Mexico)

    2000-07-01

    Europium as waste can produce a pollution problem in water that is in contact with it, what would has a heavy environmental impacts, because of the possibilities of diffusion of these wastes from their place of confinement or storage until the geo and biosphere. The solution of such problem requires of a lot of knowledge over the behavior of several chemical elements such as europium in aqueous solutions. In this work it was used a low ion force (0.02 M). The data set will allow extrapolate the hydrolytic behavior of europium in too much minors ion force media, such as the ground waters, including in ion force zero.

  1. Alkali Silicate Vehicle Forms Durable, Fireproof Paint

    Science.gov (United States)

    Schutt, John B.; Seindenberg, Benjamin

    1964-01-01

    The problem: To develop a paint for use on satellites or space vehicles that exhibits high resistance to cracking, peeling, or flaking when subjected to a wide range of temperatures. Organic coatings will partially meet the required specifications but have the inherent disadvantage of combustibility. Alkali-silicate binders, used in some industrial coatings and adhesives, show evidence of forming a fireproof paint, but the problem of high surface-tension, a characteristic of alkali silicates, has not been resolved. The solution: Use of a suitable non-ionic wetting agent combined with a paint incorporating alkali silicate as the binder.

  2. Model Dust Envelopes Around Silicate Carbon Stars

    Directory of Open Access Journals (Sweden)

    Kyung-Won Suh

    2006-03-01

    Full Text Available We have modeled dust envelopes around silicate carbon stars using optical properties for a mixture of amorphous carbon and silicate dust grains paying close attention to the infrared observations of the stars. The 4 stars show various properties in chemistry and location of the dust shell. We expect that the objects that fit a simple detached silicate dust shell model could be in the transition phase of the stellar chemistry. For binary system objects, we find that a mixed dust chemistry model would be necessary.

  3. Thermodynamic and structural description of europium complexation in 1-octanol - H{sub 2}O solutions

    Energy Technology Data Exchange (ETDEWEB)

    Vu, T.H.; Charbonnel, M.C.; Boubals, N.; Couston, L. [CEA Marcoule, DEN/DRCP/SCPS/LCAM, BP 17171, 30207 Bagnols-sur-Ceze (France); Arnaud, F. [Laboratoire de Chimie Physique, IPHC, 25 rue Becquerel, 67087 Strasbourg (France)

    2008-07-01

    Polydentate N-bearing ligands such as bis-triazinyl-pyridines (BTPs) are interesting extractants for actinide(III)/lanthanide(III) separation. A description of europium complexation in 1-octanol solutions was undertaken to enhance the knowledge of the extraction mechanisms. The first solvation shell for europium(III) nitrate, chloride, and perchlorate with different amounts of water was determined by Time-Resolved Laser-Induced Fluorescence (TRLIF) spectroscopy. Europium nitrate complexation by iPr-BTP was then studied by TRLIF and micro-calorimetry; similar stability constants related to the formation of Eu(BTP){sub 2}{sup 3+} and Eu(BTP){sub 3}{sup 3+} were obtained by both techniques (log({beta}{sub 2}) = 9.0 {+-} 0.3 and log({beta}{sub 3}) = 13.8 {+-} 0.2). The presence of water in the octanol diluent has an influence on solvation of europium and also on the [Eu(BTP){sub 2}{sup 3+}] / [Eu(BTP){sub 3}{sup 3+}] ratio. (authors)

  4. A novel biocompatible europium ligand for sensitive time-gated immunodetection.

    Science.gov (United States)

    Sayyadi, Nima; Connally, Russell E; Try, Andrew

    2016-01-21

    We describe the synthesis of a novel hydrophilic derivative of a tetradentate β-diketone europium ligand that was used to prepare an immunoconjugate probe against Giardia lamblia cysts. We used a Gated Autosynchronous Luminescence Detector (GALD) to obtain high quality delayed luminescence images of cells 30-fold faster than ever previously reported.

  5. Europium-doped barium halide scintillators for x-ray and ?-ray detections

    NARCIS (Netherlands)

    Selling, J.; Birowosuto, M.D.; Dorenbos, P.; Schweizer, S.

    2007-01-01

    Single crystals of undoped or europium-doped barium chloride, bromide, and iodide were investigated under x-ray and ?-ray excitations. The Eu2+-related x-ray excited luminescence found in the Eu-doped barium halides occurs at 402, 404, and 425?nm for the chloride, bromide, and iodide, respectively.

  6. A europium luminescence assay of lactate and citrate in biological fluids†

    Science.gov (United States)

    Pal, Robert; Costello, Leslie C.

    2013-01-01

    Ratiometric methods of analysis have been developed for the selective determination of lactate or citrate in microlitre samples of human serum, urine or prostate fluids following comparison of anion binding affinities for a family of nine luminescent europium(III) complexes. PMID:19343236

  7. Molecular interactions of Leucoagaricus naucinus with uranium(VI) and europium(III)

    Energy Technology Data Exchange (ETDEWEB)

    Wollenberg, Anne; Raff, Johannes [Helmholtz-Zentrum Dresden-Rossendorf e.V., Dresden (Germany). Biogeochemistry; Guenther, A. [Helmholtz Institute Freiberg for Resource Technology, Freiberg (Germany)

    2017-06-01

    With regard to a molecular understanding of the interaction of fungal mycelium with radionuclides and its possible application for precautionary radiation protection and bio-remediation, the binding mechanism of the radionuclide uranium and the metal europium, as surrogate for trivalent actinides, where investigated with different starting conditions by the living fungal cells of Leucoagaricus naucinus.

  8. Europium doped In(Zn)P/ZnS colloidal quantum dots

    NARCIS (Netherlands)

    Thuy, Ung Thi Dieu; Maurice, Axel; Liem, Nguyen Quang; Reiss, Peter

    2013-01-01

    Chemically synthesised In(Zn)P alloy nanocrystals are doped with Eu(3+) ions using europium oleate as a molecular precursor and are subsequently covered with a ZnS shell. The presence of zinc in the synthesis of the InP core nanocrystals leads to the formation of an In(Zn)P alloy structure, making

  9. NO fluorescence sensing by europium tetracyclines complexes in the presence of H2O2.

    Science.gov (United States)

    Simões, Eliana F C; Leitão, João M M; Esteves da Silva, Joaquim C G

    2013-07-01

    The effect on the fluorescence of the europium:tetracycline (Eu:Tc), europium:oxytetracycline (Eu:OxyTc) and europium:chlortetracycline (Eu:ClTc) complexes in approximately 2:1 ratio of nitric oxide (NO), peroxynitrite (ONOO(-)), hydrogen peroxide (H2O2) and superoxide (O2 (·-)) was assessed at three ROS/RNS concentrations levels, 30 °C and pH 6.00, 7.00 and 8.00. Except for the NO, an enhancement of fluorescence intensity was observed at pH 7.00 for all the europium tetracyclines complexes-the high enhancement was observed for H2O2. The quenching of the fluorescence of the Tc complexes, without and with the presence of other ROS/RNS species, provoked by NO constituted the bases for an analytical strategy for NO detection. The quantification capability was evaluated in a NO donor and in a standard solution. Good quantification results were obtained with the Eu:Tc (3:1) and Eu:OxyTc (4:1) complexes in the presence of H2O2 200 μM with a detection limit of about 3 μM (Eu:OxyTc).

  10. Long-term tagging of elvers, Anguilla anguilla, with radioactive europium

    DEFF Research Database (Denmark)

    Hansen, Heinz Johs. Max; Fattah, A. T. A.

    1986-01-01

    -life of added europium of 1.6 .+-. 0.5 years. Thirteen hundred 155Eu-labelled elvers (50 Bq per eel), each weighing on average 0.21 g, were set out near Oskarshamn on the east coast of Sweden in June 1982. Three of these were caught nearby in May 1985 and one was caught in August 1985. They weighed...

  11. ULTRAVIOLET TRANSITIONS IN EUROPIUM STUDIED WITH A FREQUENCY-DOUBLED CW RING DYE-LASER

    NARCIS (Netherlands)

    Eliel, E.R.; Hogervorst, W.; van Leeuwen, K.A.H.; Post, B.H.

    1981-01-01

    High resolution laser spectroscopy has been applied to the study of three ultraviolet transitions in Europium at λ = 294.8, 295.1 and 295.8 nm. The tunable narrowband UV has been generated by intracavity frequency doubling in a cw ring dye laser using a temperate tuned, Brewster angled ADA crystal.

  12. Optical and Morphological Characterization of Sonochemically Assisted Europium Doped Copper (I) Oxide Nanostructures

    Science.gov (United States)

    Cosico, J. A. M.; Ruales, P. K.; Marquez, M. C.

    2017-06-01

    In the age where application of nanotechnology in our society has proven to be eminent, different routes of synthesizing nanoparticles have emerged. In this study nanoparticles of cuprous oxide (Cu2O) doped with different amounts of europium was prepared by using solution precursor route approach with the aid of ultrasonic sound. Copper sulphate and europium (III) nitrate pentahydrate was used as source for copper ions and europium ions respectively. X-ray diffraction (XRD) and Fourier Transform Infrared spectroscopy (FTIR) were used to elucidate the cubic crystal structure and organic impurities present on Cu2Onanoparticles. UV-Vis spectroscopy was used to determine the absorption spectrum of the nanoparticles in the wavelength range of 400nm to 700nm. The bandgap of the undoped and doped Cu2O were found to fall between 2.1eV - 2.3eV. Scanning Electron Microscopy (SEM) coupled with energy dispersive x-ray was used to observe the dendritic and rodlike morphology and the presence of europium in the synthesized Cu2O nanoparticles. The observed effect on the absorbance of Cu2O upon adding Eu and a facile way of synthesizing Cu2O nanoparticles could bring a positive impact on the production of functional devices for optoelectronic and energy applications.

  13. Siliceous microfossil extraction from altered Monterey rocks

    Energy Technology Data Exchange (ETDEWEB)

    Nelson, C.O.; Casey, R.E.

    1986-04-01

    Samples of altered Monterey rocks of differing lithologies were processed by various methods to develop new techniques for extracting siliceous microfossils. The preliminary use of thin sections made from the same rocks reduced the number of probable samples (samples worth further processing) by about one-third. Most of the siliceous microfossils contained in altered Monterey rocks appear to be highly recrystallized and are extremely fragile; however, some contained silicified and silica-infilled radiolarians and planktonic and benthonic foraminifera, which are very tough. In general the most useful techniques were gently hydrochloric acid, hydrogen peroxide, formic acid, monosodium glutamate, and regular siliceous microfossil extraction techniques. Unsuccessful techniques and a new siliceous microfossil flotation technique are also documented.

  14. Carbon Monoxide Silicate Reduction System Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The Carbon Monoxide Silicate Reduction System (COSRS) is a novel technology for producing large quantities of oxygen on the Moon. Oxygen yields of 15 kilograms per...

  15. Carbon Monoxide Silicate Reduction System Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The Carbon Monoxide Silicate Reduction System (COSRS) is an innovative method that for the first time uses the strong reductant carbon monoxide to both reduce iron...

  16. Peralkaline silicic volcanic rocks in northwestern nevada.

    Science.gov (United States)

    Noble, D C; Chipman, D W; Giles, D L

    1968-06-21

    Late Tertiary silicic ashflow tuffs and lavas peralkaline in chemical character (atomic Na + K greater than Al), mainly comendites, occur over wide areas in northwestern Nevada and appear to be widespread in southeastern Oregon. Such peralkaline rocks-which are not uncommon in the western United States-and other chemically unusual silicic rocks are found near the margins rather than toward the center of the Great Basin.

  17. Thermodynamics and Kinetics of Silicate Vaporization

    Science.gov (United States)

    Jacobson, Nathan S.; Costa, Gustavo C. C.

    2015-01-01

    Silicates are a common class of materials that are often exposed to high temperatures. The behavior of these materials needs to be understood for applications as high temperature coatings in material science as well as the constituents of lava for geological considerations. The vaporization behavior of these materials is an important aspect of their high temperature behavior and it also provides fundamental thermodynamic data. The application of Knudsen effusion mass spectrometry (KEMS) to silicates is discussed. There are several special considerations for silicates. The first is selection of an appropriate cell material, which is either nearly inert or has well-understood interactions with the silicate. The second consideration is proper measurement of the low vapor pressures. This can be circumvented by using a reducing agent to boost the vapor pressure without changing the solid composition or by working at very high temperatures. The third consideration deals with kinetic barriers to vaporization. The measurement of these barriers, as encompassed in a vaporization coefficient, is discussed. Current measured data of rare earth silicates for high temperature coating applications are discussed. In addition, data on magnesium-iron-silicates (olivine) are presented and discussed.

  18. Occurrence of photoluminescence and onion like structures decorating graphene oxide with europium using sodium dodecyl sulfate surfactant

    Science.gov (United States)

    Cedeño, V. J.; Rangel, R.; Cervantes, J. L.; Lara, J.; Alvarado, J. J.; Galván, D. H.

    2017-07-01

    Graphene oxide decoration with europium was carried out using SDS (sodium dodecyl sulfate) as the surfactant. The reaction was performed in a microwave oven and subsequently underwent thermal treatment under hydrogen flow. The results found in the present work demonstrate that through the use of SDS surfactant aggregates of hemi-cylindrical and onion-like structures could be obtained; which propitiate an enhanced synergistic photoluminescence located at the red wavelength. On the other hand, after thermal treatment the aggregates disappear providing a good dispersion of europium, however a decrease in the photoluminescence signal is observed. The graphene oxide decorated with europium was characterized by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), Fourier infrared transform spectroscopy (FTIR), RAMAN spectroscopy, x-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM) techniques, showing the characteristic features of graphene oxide and europium.

  19. Synthesis, characterization, and properties of reduced europium molybdates and tungstates

    Energy Technology Data Exchange (ETDEWEB)

    Abeysinghe, Dileka [Department of Chemistry and Biochemistry, University of South Carolina, Columbia, SC 29208 (United States); Gerke, Birgit [Institut für Anorganische und Analytische Chemie, Universität Münster , Corrensstrasse 30, Münster D-48149 (Germany); Morrison, Gregory; Hsieh, Chun H.; Smith, Mark D. [Department of Chemistry and Biochemistry, University of South Carolina, Columbia, SC 29208 (United States); Pöttgen, Rainer [Institut für Anorganische und Analytische Chemie, Universität Münster , Corrensstrasse 30, Münster D-48149 (Germany); Makris, Thomas M. [Department of Chemistry and Biochemistry, University of South Carolina, Columbia, SC 29208 (United States); Loye, Hans-Conrad zur, E-mail: zurloye@mailbox.sc.edu [Department of Chemistry and Biochemistry, University of South Carolina, Columbia, SC 29208 (United States)

    2015-09-15

    Single crystals of K{sub 0.094}Eu{sub 0.906}MoO{sub 4}, K{sub 0.097}Eu{sub 0.903}WO{sub 4}, EuWO{sub 4}, and EuMoO{sub 4} were grown from molten chloride fluxes contained in vacuum-sealed fused silica and structurally characterized via single crystal X-ray diffraction. The in situ reduction of Eu{sup 3+} to Eu{sup 2+} was carried out using Mo, W, and Zn as metal reducing agents. All four compounds crystallize in the tetragonal space group of I4{sub 1}/a and adopt the scheelite (CaWO{sub 4}) structure type. The magnetic susceptibility of the reported compounds shows paramagnetic behavior down to 2 K. {sup 151}Eu Mössbauer spectroscopy was used to analyze the relative Eu{sup 2+} and Eu{sup 3+} content of the samples. All the compounds were further characterized by EPR, and UV-vis spectroscopy. - Graphical abstract: TOC Caption Two new reduced europium containing quaternary oxides, K{sub 0.094}Eu{sub 0.906}MoO{sub 4} and K{sub 0.097}Eu{sub 0.903}WO{sub 4}, and two previously reported ternary reduced oxides, EuWO{sub 4} and EuMoO{sub 4}, were synthesized via an in situ reduction of Eu{sup 3+} to Eu{sup 2+} under flux method using Mo, W, and Zn as metal reducing agents. {sup 151}Eu Mössbauer spectroscopy was used to analyze the relative Eu{sup 2+} and Eu{sup 3+} content of the samples. - Highlights: • K{sub 0.094}Eu{sub 0.906}MoO{sub 4}, K{sub 0.097}Eu{sub 0.903}WO{sub 4}, EuWO{sub 4}, and EuMoO{sub 4} have been synthesized and characterized. • The in situ reduction of Eu{sup 3+} to Eu{sup 2+} was carried out using Mo, W, and Zn as metal reducing agents. • Magnetic susceptibility data were collected. • {sup 151}Eu Mössbauer spectroscopy was used to analyze Eu{sup 2+} and Eu{sup 3+} content.

  20. A highly sensitive and selective fluorescent sensor for detection of Al(3+) using a europium(III) quinolinecarboxylate.

    Science.gov (United States)

    Xu, Wentao; Zhou, Youfu; Huang, Decai; Su, Mingyi; Wang, Kun; Hong, Maochun

    2014-07-07

    Eu2PQC6 has been developed to detect Al(3+) by monitoring the quenching of the europium-based emission, with the lowest detection limit of ∼32 pM and the quantitative detection range to 150 μM. Eu2PQC6 is the first ever example that the europium(III) complex serves as an Al(3+) fluorescent sensor based on "competition-displacement" mode.

  1. Hyperfine interactions at europium sites in oxide glasses

    Science.gov (United States)

    Concas, G.; Congiu, F.; Muntoni, C.; Bettinelli, M.; Speghini, A.

    1996-03-01

    The shape of the γ resonance absorption peak of the Eu3+ ion in a disordered structure was investigated in some phosphate, borate, and silicate glasses by using 151Eu Mössbauer spectroscopy. The quality of the fits was tested by using the Durbin-Watson d statistics. The observed full width at half maximum of the peak was resolved in a contribution of the broadening and a contribution of the quadrupole splitting, due to the distortion of the Eu site compared to a cubic symmetry. The Eu-O bond was found to have a covalent admixture with 6s character. The axial component of the electric-field gradient at the Eu site was found to be correlated with the optical basicity of the glass.

  2. The effect of two additional Eu3+ lumophors in two novel trinuclear europium complexes on their photoluminescent properties.

    Science.gov (United States)

    Yang, Chaolong; Xu, Jing; Ma, Jianying; Zhu, Dongyu; Zhang, Yunfei; Liang, Liyan; Lu, Mangeng

    2013-02-01

    Two novel trinuclear europium complexes based on trisphen(1,3,5-tris{4-((1,10-phenanthroline-[5,6-d]imidazol-2yl)phenoxy)methyl}-2,4,6-trimethyl-benzene) as a second ligand were designed, synthesized, and characterized by FT-IR, (1)H NMR, UV-visible, photoluminescence (PL) spectroscopy, elemental analysis (EA) and ESI-MS. The geometries of these two trinuclear europium complexes were predicted using the Sparkle/PM3 model and suggested a chemical environment of very low symmetry around the lanthanide ions (C(1)), which is in agreement with the luminescent spectra. CV analysis demonstrated that the trinuclear complexes possessed excellent electro-injection abilities. The effects of two additional Eu(3+) lumophors in these trinuclear europium complexes on their photoluminescent properties were investigated in detail. The results indicated that these trinuclear europium complexes exhibited highly luminescent quantum efficiencies and experimental intensity parameters in the solid state. Especially, due to the contribution of the two additional Eu(3+) lumophors in the trinuclear europium complexes, the quantum efficiency of the trinuclear complex Eu(3)(TTA)(9)trisphen was higher (ca. 34%) than the mononuclear europium complex Eu(TTA)(3)imidazophen.

  3. Influence of biofilms on migration of uranium, americium and europium in the environment; Einfluss von Biofilmen auf das Migrationsverhalten von Uran, Americium und Europium in der Umwelt

    Energy Technology Data Exchange (ETDEWEB)

    Baumann, Nils; Zirnstein, Isabel; Arnold, Thuro

    2015-07-01

    The report on the influence of biofilms on migration of uranium, americium and europium in the environment deals with the contamination problems of uranium mines such as SDAG WISMUT in Saxonia and Thuringia. In mine waters microorganisms form a complex microbiological biocoenosis in spite of low pH values and high heavy metal concentrations including high uranium concentrations. The analyses used microbiological methods like confocal laser scanning microscopy and molecular-biological techniques. The interactions of microorganism with fluorescent radioactive heavy metal ions were performed with TRLFS (time resolved laser-induced fluorescence spectroscopy).

  4. Incorporation of europium III complex into nanoparticles and films obtained by the Sol-Gel methodology

    Directory of Open Access Journals (Sweden)

    Faley Jean de Sousa

    2010-03-01

    Full Text Available The sol-gel process is very effective for the preparation of new materials with potential applications in optics, sensors, catalyst supports, coatings, and specialty inorganic polymers that can be used as hosts for the accommodation of organic molecules. The low temperature employed in the process is the main advantage of this methodology. In this work, the europium (III complex with 1,10-phenantroline was prepared, and this luminescent complex was incorporated into silica nanoparticles and films by the sol-gel process. The nanoparticles were obtained by the modified Stöber methodology. The films were obtained by the dip-coating technique, at different deposition rates and numbers of layers. The nanoparticles and films were characterized by photoluminescence, thermal analysis, and Raman and infrared spectroscopies. Characterization revealed that the europium (III complex was not affected upon incorporation into the nanoparticles and films, opening a new field for the application of these materials.

  5. A Simple and Sensitive Method to Quantify Biodegradable Nanoparticle Biodistribution using Europium Chelates.

    Science.gov (United States)

    Crawford, Lindsey; Higgins, Jaclyn; Putnam, David

    2015-09-08

    The biodistribution of biodegradable nanoparticles can be difficult to quantify. We report a method using time resolved fluorescence (TRF) from a lanthanide chelate to minimize background autofluorescence and maximize the signal to noise ratio to detect biodegradable nanoparticle distribution in mice. Specifically, antenna chelates containing europium were entrapped within nanoparticles composed of polylactic acid-polyethylene glycol diblock copolymers. Tissue accumulation of nanoparticles following intravenous injection was quantified in mice. The TRF of the nanoparticles was found to diminish as a second order function in the presence of serum and tissue compositions interfered with the europium signal. Both phenomena were corrected by linearization of the signal function and calculation of tissue-specific interference, respectively. Overall, the method is simple and robust with a detection limit five times greater than standard fluorescent probes.

  6. A Comprehensive Strategy to Boost the Quantum Yield of Luminescence of Europium Complexes

    Science.gov (United States)

    Lima, Nathalia B. D.; Gonçalves, Simone M. C.; Júnior, Severino A.; Simas, Alfredo M.

    2013-01-01

    Lanthanide luminescence has many important applications in anion sensing, protein recognition, nanosized phosphorescent devices, optoelectronic devices, immunoassays, etc. Luminescent europium complexes, in particular, act as light conversion molecular devices by absorbing ultraviolet (UV) light and by emitting light in the red visible spectral region. The quantum yield of luminescence is defined as the ratio of the number of photons emitted over the number of UV photons absorbed. The higher the quantum yield of luminescence, the higher the sensitivity of the application. Here we advance a conjecture that allows the design of europium complexes with higher values of quantum yields by simply increasing the diversity of good ligands coordinated to the lanthanide ion. Indeed, for the studied cases, the percent boost obtained on the quantum yield proved to be strong: of up to 81%, accompanied by faster radiative rate constants, since the emission becomes less forbidden. PMID:23928866

  7. Assembly of europium organic framework–gold nanoparticle composite thin films on silicon substrate

    Energy Technology Data Exchange (ETDEWEB)

    Deep, Akash, E-mail: dr.akashdeep@gmail.com [Central Scientific Instruments Organisation (CSIR-CSIO), Sector 30 C, Chandigarh 160030 (India); Academy of Scientific and Innovative Research, CSIR-CSIO, Sector 30 C, Chandigarh 160030 (India); Kaur, Rajnish [Central Scientific Instruments Organisation (CSIR-CSIO), Sector 30 C, Chandigarh 160030 (India); Academy of Scientific and Innovative Research, CSIR-CSIO, Sector 30 C, Chandigarh 160030 (India); Kumar, Parveen [Central Scientific Instruments Organisation (CSIR-CSIO), Sector 30 C, Chandigarh 160030 (India); Kumar, Pawan; Paul, A.K. [Central Scientific Instruments Organisation (CSIR-CSIO), Sector 30 C, Chandigarh 160030 (India); Academy of Scientific and Innovative Research, CSIR-CSIO, Sector 30 C, Chandigarh 160030 (India)

    2014-08-28

    Metal organic frameworks are a sub-class of coordination polymers and rapidly generating huge research interests in several technological areas. One of the emerging areas of their potential applications is the photovoltaics. The present study proposes the assembly of europium organic framework–gold nanoparticle nanocomposite thin film on silicon substrate. Microscopic, X-ray diffraction, surface area measurement and thermal studies have indicated the formation of the desired thin film. Spectral studies have been used to highlight their solid state optical property. Current–voltage studies have established semiconducting property of the above thin films. - Highlights: • Thin film of europium organic framework/gold nanoparticles is prepared on silicon. • Fairly homogeneous films with a roughness factor of 5–10 nm are obtained. • Above thin films offer solid-state photoluminescence and semiconducting properties.

  8. Hydrothermal Synthesis of Dicalcium Silicate Based Cement

    Science.gov (United States)

    Dutta, N.; Chatterjee, A.

    2017-06-01

    It is imperative to develop low energy alternative binders considering the large amounts of energy consumed as well as carbon dioxide emissions involved in the manufacturing of ordinary Portland cement. This study is on the synthesis of a dicalcium silicate based binder using a low temperature hydrothermal route.The process consists of synthesizing an intermediate product consisting of a calcium silicate hydrate phase with a Ca:Si ratio of 2:1 and further thermal treatment to produce the β-Ca2SiO4 (C2S) phase.Effect of various synthesis parameters like water to solid ratio, dwell time and temperature on the formation of the desired calcium silicate hydrate phase is reported along with effect of heating conditions for formation of the β-C2S phase. Around 77.45% of β-C2S phase was synthesized by thermal treatment of the intermediate phase at 820°C.

  9. Development of a microchip Europium nanoparticle immunoassay for sensitive point-of-care HIV detection.

    Science.gov (United States)

    Liu, Jikun; Du, Bingchen; Zhang, Panhe; Haleyurgirisetty, Mohan; Zhao, Jiangqin; Ragupathy, Viswanath; Lee, Sherwin; DeVoe, Don L; Hewlett, Indira K

    2014-11-15

    Rapid, sensitive and specific diagnostic assays play an indispensable role in determination of HIV infection stages and evaluation of efficacy of antiretroviral therapy. Recently, our laboratory developed a sensitive Europium nanoparticle-based microtiter-plate immunoassay capable of detecting target analytes at subpicogram per milliliter levels without the use of catalytic enzymes and signal amplification processes. Encouraged by its sensitivity and simplicity, we continued to miniaturize this assay to a microchip platform for the purpose of converting the benchtop assay technique to a point-of-care test. It was found that detection capability of the microchip platform could be readily improved using Europium nanoparticle probes. We were able to routinely detect 5 pg/mL (4.6 attomoles) of HIV-1 p24 antigen at a signal-to-blank ratio of 1.5, a sensitivity level reasonably close to that of microtiter-plate Europium nanoparticle assay. Meanwhile, use of the microchip platform effectively reduced sample/reagent consumption 4.5 fold and shortened total assay time 2 fold in comparison with microtiter plate assays. Complex matrix substance in plasma negatively affected the microchip assays and the effects could be minimized by diluting the samples before loading. With further improvements in sensitivity, reproducibility, usability, assay process simplification, and incorporation of portable time-resolved fluorescence reader, Europium nanoparticle immunoassay technology could be adapted to meet the challenges of point-of-care diagnosis of HIV or other health-threatening pathogens at bedside or in resource-limited settings. Copyright © 2014 Elsevier B.V. All rights reserved.

  10. Green Luminescence of Divalent Europium in the Hydride Chloride EuHCl

    NARCIS (Netherlands)

    Kunkel, Nathalie; Rudolph, Daniel; Meijerink, A; Rommel, Stefan; Weihrich, Richard; Kohlmann, Holger; Schleid, Thomas

    Luminescence properties of divalent europium in the mixed-anion hydride chloride EuHCl were studied for the first time. Olive-green single crystals of EuHCl (PbFCl-type structure: tetragonal, P4/nmm, a = 406.58(3) pm, c = 693.12(5) pm, c/a = 1.705, Z = 2) resulted from the reaction of elemental

  11. Silicate mineral dissolution during heap bioleaching.

    Science.gov (United States)

    Dopson, Mark; Halinen, Anna-Kaisa; Rahunen, Nelli; Boström, Dan; Sundkvist, Jan-Eric; Riekkola-Vanhanen, Marja; Kaksonen, Anna H; Puhakka, Jaakko A

    2008-03-01

    Silicate minerals are present in association with metal sulfides in ores and their dissolution occurs when the sulfide minerals are bioleached in heaps for metal recovery. It has previously been suggested that silicate mineral dissolution can affect mineral bioleaching by acid consumption, release of trace elements, and increasing the viscosity of the leach solution. In this study, the effect of silicates present in three separate samples in conjunction with chalcopyrite and a complex multi-metal sulfide ore on heap bioleaching was evaluated in column bioreactors. Fe(2+) oxidation was inhibited in columns containing chalcopyrite samples A and C that leached 1.79 and 1.11 mM fluoride, respectively but not in sample B that contained 0.14 mM fluoride. Microbial Fe(2+) oxidation inhibition experiments containing elevated fluoride concentrations and measurements of fluoride release from the chalcopyrite ores supported that inhibition of Fe(2+) oxidation during column leaching of two of the chalcopyrite ores was due to fluoride toxicity. Column bioleaching of the complex sulfide ore was carried out at various temperatures (7-50 degrees C) and pH values (1.5-3.0). Column leaching at pH 1.5 and 2.0 resulted in increased acid consumption rates and silicate dissolution such that it became difficult to filter the leach solutions and for the leach liquor to percolate through the column. However, column temperature (at pH 2.5) only had a minor effect on the acid consumption and silicate dissolution rates. This study demonstrates the potential negative impact of silicate mineral dissolution on heap bioleaching by microbial inhibition and liquid flow. Copyright 2007 Wiley Periodicals, Inc.

  12. Ferromagnetic semiconductor-metal transition in heterostructures of electron doped europium monoxide

    Energy Technology Data Exchange (ETDEWEB)

    Stollenwerk, Tobias

    2013-09-15

    In the present work, we develop and solve a self-consistent theory for the description of the simultaneous ferromagnetic semiconductor-metal transition in electron doped Europium monoxide. We investigate two different types of electron doping, Gadolinium impurities and Oxygen vacancies. Besides the conduction band occupation, we can identify low lying spin fluctuations on magnetic impurities as the driving force behind the doping induced enhancement of the Curie temperature. Moreover, we predict the signatures of these magnetic impurities in the spectra of scanning tunneling microscope experiments. By extending the theory to allow for inhomogeneities in one spatial direction, we are able to investigate thin films and heterostructures of Gadolinium doped Europium monoxide. Here, we are able to reproduce the experimentally observed decrease of the Curie temperature with the film thickness. This behavior is attributed to missing coupling partners of the localized 4f moments as well as to an electron depletion at the surface which leads to a reduction of the number of itinerant electrons. By investigating the influence of a metallic substrate onto the phase transition in Gadolinium doped Europium monoxide, we find that the Curie temperature can be increased up to 20%. However, as we show, the underlying mechanism of metal-interface induced charge carrier accumulation is inextricably connected to a suppression of the semiconductor-metal transition.

  13. Redox electrochemistry of europium fluoride complexes in an equimolar NaCl-KCl melt

    Energy Technology Data Exchange (ETDEWEB)

    Kuznetsov, S.A., E-mail: kuznet@chemy.kolasc.net.ru [Institute of Chemistry, Kola Science Centre RAS, 26 Akademgorodok., 184209 Apatity, Murmansk region (Russian Federation); Gaune-Escard, M. [Ecole Polytechnique, Mecanique Energetique, Technopole de Chateau Gombert, 5 rue Enrico Fermi, 13453 Marseille Cedex 13 (France)

    2011-07-15

    The electrochemical behavior of europium fluoride complexes was studied by different electrochemical methods at a glassy carbon electrode in the temperature range 973-1100 K in the NaCl-KCl melt. The diffusion coefficients of Eu(III) and Eu(II) were determined by linear sweep voltammetry. The standard rate constants of charge transfer for the Eu(III)/Eu(II) redox couple were found on the base cyclic voltammetry, impedance spectroscopy and chronoamperometry data. The formal standard redox potentials E{sub Eu(III)/Eu(II)}{sup *} were obtained by linear sweep and cyclic voltammetry. The electrochemical behavior of europium fluoride and europium chloride complexes in NaCl-KCl melt was compared and discussed in connection with the strength and stability of these complexes. It was shown that the formation of stronger fluoride complexes reduced values of diffusion coefficients, standard rate constants for charge transfer of the Eu(III)/Eu(II) redox couple and shifted the formal standard redox potentials to the more electronegative values.

  14. Lateral flow immunoassay using europium chelate-loaded silica nanoparticles as labels.

    Science.gov (United States)

    Xia, Xiaohu; Xu, Ye; Zhao, Xilin; Li, Qingge

    2009-01-01

    Despite their ease of use, lateral flow immunoassays (LFIAs) often suffer from poor quantitative discrimination and low analytical sensitivity. We explored the use of a novel class of europium chelate-loaded silica nanoparticles as labels to overcome these limitations. Antibodies were covalently conjugated onto europium chelate-loaded silica nanoparticles with dextran as a linker. The resulting conjugates were used as labels in LFIA for detection of hepatitis B surface antigen (HBsAg). We performed quantification with a digital camera and Adobe Photoshop software. We also used 286 clinical samples to compare the proposed method with a quantitative ELISA. A detection limit of 0.03 microg/L was achieved, which was 100 times lower than the colloidal gold-based LFIAs and lower than ELISA. A precise quantitative dose-response curve was obtained, and the linear measurement range was 0.05-3.13 microg/L, within which the CVs were 2.3%-10.4%. Regression analysis of LFIA on ELISA results gave: log (LFIA) = -0.14 log (ELISA) + 1.03 microg/L with r = 0.99 for the quantification of HBsAg in 35 positive serum samples. Complete agreement was observed for the qualitative comparison of 286 clinical samples assayed with LFIA and ELISA. Europium chelate-loaded silica nanoparticle labels have great potential to improve LFIAs, making them useful not only for simple screening applications but also for more sensitive and quantitative immunoassays.

  15. Luminescent solutions and films of new europium complexes with chelating ligands

    Science.gov (United States)

    Kharcheva, Anastasia V.; Ivanov, Alexey V.; Borisova, Nataliya E.; Kaminskaya, Tatiana P.; Patsaeva, Svetlana V.; Popov, Vladimir V.; Yuzhakov, Viktor I.

    2015-03-01

    The development of new complexes of rare earth elements (REE) with chelating organic ligands opens up the possibility of purposeful alteration in the composition and structure of the complexes, and therefore tuning their optical properties. New ligands possessing two pyridine rings in their structure were synthesized to improve coordination properties and photophysical characteristics of REE compounds. Complexes of trivalent europium with novel chelating ligands were investigated using luminescence and absorption spectroscopy, as well as atomic force microscopy. Luminescence properties of new compounds were studied both for solutions and films deposited on the solid support. All complexes exhibit the characteristic red luminescence of Eu (III) ion with the absolute lumenescence quantum yield in polar acetonitrile solution varying from 0.21 to 1.45 % and emission lifetime ranged from 0.1 to 1 ms. Excitation spectra of Eu coordination complexes correspond with absorption bands of chelating ligand. The energy levels of the triplet state of the new ligands were determined from the phosphorescence at 77 K of the corresponding Gd (III) complexes. The morphology of films of europium complexes with different substituents in the organic ligands was investigated by atomic force microscopy (AFM). It strongly depends both on the type of substituent in the organic ligand, and the rotation speed of the spin-coater. New europium complexes with chelating ligands containing additional pyridine fragments represent outstanding candidates for phosphors with improved luminescence properties.

  16. Use of europium ions for SAD phasing of lysozyme at the Cu Kα wavelength.

    Science.gov (United States)

    Vijayakumar, Balakrishnan; Velmurugan, Devadasan

    2013-01-01

    Europium is shown to be a good anomalous scatterer in SAD phasing for solving the structure of biological macromolecules. The large value of the anomalous contribution of europium, f'' = 11.17 e(-), at the Cu Kα wavelength is an advantage in de novo phasing and automated model building. Tetragonal crystals of hen egg-white lysozyme (HEWL) incorporating europium(III) chloride (50 mM) were obtained which diffracted to a resolution of 2.3 Å at a wavelength of 1.54 Å (Cu Kα). The master data set (360° frames) was split and analyzed for anomalous signal-to-noise ratio, multiplicity, completeness, SAD phasing and automated building. The structure solution and model building of the split data sets were carried out using phenix.autosol and phenix.autobuild. The contributions of the Eu ions to SAD phasing using in-house data collection are discussed. This study revealed successful lysozyme phasing by SAD using laboratory-source data involving Eu ions, which are mainly coordinated by the side chains of Asn46, Asp52 and Asp101 together with some water molecules.

  17. Hydrothermal treatment for preparation of europium-lanthanum phosphates and exploration of their fluorescence properties

    Directory of Open Access Journals (Sweden)

    Hiroaki Onoda

    2014-04-01

    Full Text Available Europium-substituted lanthanum phosphates (Eu; 5 mol% were prepared from lanthanum nitrate, europium nitrate, and sodium polyphosphate solutions by a hydrothermal process at 120 and 160 °C up to 8 h. The obtained phosphates were studied using XRD, IR spectroscopy, TG–DTA, and SEM. UV–vis absorbance and reflectance, as well as fluorescence, were estimated as functional properties of these phosphate materials. We found that samples prepared without hydrothermal treatment were amorphous (as indicated by their XRD patterns, whereas those prepared by a hydrothermal treatment contained peaks corresponding to lanthanum orthophosphate, indicating that the hydrothermal process caused the polyphosphate(s to decompose into orthophosphate(s. The TG–DTA curves of the samples prepared by a hydrothermal treatment were different from those of the samples prepared without hydrothermal treatment. All samples reported herein had no specified shape despite using prolonged hydrothermal treatment times. Although the samples prepared without hydrothermal treatment showed only weak fluorescence peaks, those prepared by a hydrothermal treatment showed strong peaks at 556, 590, 615, and 690 nm. These peaks corresponded to transitions from 5D0 to 7F0, 7F1, 7F2, and 7F4, respectively. Collectively, these results indicate that the hydrothermal treatment is a useful method of obtaining europium-substituted lanthanum phosphates with fluorescence properties.

  18. Fabrication of coated graphite electrode for the selective determination of europium (III) ions.

    Science.gov (United States)

    Upadhyay, Anjali; Singh, Ashok Kumar; Bandi, Koteswara Rao; Jain, A K

    2013-10-15

    Preliminary complexation study showed that two ligands (ionophores) (2-((2-phenyl-2-(pyridin-2-yl)hydazono)methyl)pyridine) [L1], (2-((2-phenyl-2-(pyridin-2-yl)hydazono) methyl)phenol) [L2] can act as europium selective electrode. Europium selective coated graphite electrodes (CGE) were prepared by using ligands [L1] and [L2] and their potentiometric characteristics were determined. Membranes having different compositions of poly(vinylchloride) (PVC), the different plasticizers, anionic additives and ionophores were coated onto the graphite surface. The potential response measurements showed that the best performance was exhibited by the proposed CGE. This electrode had the widest working concentration range, Nernstian slope and fast response times of 10s. The selectivity studies showed that this electrode have higher selectivity towards Eu(3+) over a large number of cations. Furthermore, the electrode generated constant potentials in the pH range 2.7-9.0. This electrode can be used to quantify europium in soil, binary mixtures and also used as an indicator electrode in the potentiometric titration of Eu(3+) with EDTA. The proposed electrode was also successfully applied to the determination of fluoride ions in real samples. © 2013 Elsevier B.V. All rights reserved.

  19. Fluorescent Sulfur-Tagged Europium(III) Coordination Polymers for Monitoring Reactive Oxygen Species.

    Science.gov (United States)

    Wang, Huai-Song; Bao, Wen-Jing; Ren, Shi-Bin; Chen, Ming; Wang, Kang; Xia, Xing-Hua

    2015-07-07

    Oxidative stress caused by reactive oxygen species (ROS) is harmful to biological systems and implicated in various diseases. A variety of selective fluorescent probes have been developed for detecting ROS to uncover their biological functions. Generally, the preparation of the fluorescent probes usually undergoes multiple synthetic steps, and the successful fluorescent sensing usually relies on trial-and-error tests. Herein we present a simple way to prepare fluorescent ROS probes that can be used both in biological and environmental systems. The fluorescent europium(III) coordination polymers (CPs) are prepared by simply mixing the precursors [2,2'-thiodiacetic acid and Eu(NO3)3·6H2O] in ethanol. Interestingly, with the increase of reaction temperature, the product undergoes a morphological transformation from microcrystal to nanoparticle while the structure and fluorescent properties retain. The fluorescence of the sulfur-tagged europium(III) CPs can be selectively quenched by ROS, and thus, sensitive and selective monitoring of ROS in aerosols by the microcrystals and in live cells by the nanoparticles has been achieved. The results reveal that the sulfur-tagged europium(III) CPs provide a novel sensor for imaging ROS in biological and environmental systems.

  20. Facile Synthesis, Characterization, and Cytotoxic Activity of Europium-Doped Nanohydroxyapatite

    Science.gov (United States)

    Niño-Martínez, Nereyda; Patiño-Marín, Nuria

    2016-01-01

    The objective of this study was to synthetize europium-doped nanohydroxyapatite using a simple aqueous precipitation method and, thereafter, characterize and impregnate selected samples with 5-fluorouracil in order to explore the properties and the releasing capacity of this material. The nanohydroxyapatite was doped with 3, 5, 10, and 20 wt% of europium. The obtained samples were characterized after they were dried at 80°C and hydrothermal treated at 120°C by 2 hours. The samples were analyzed by transmission electron microscopy, X-ray diffraction analysis, Fourier transform infrared spectroscopy, and photoluminescence. Also, impregnation and release of 5-fluorouracil were assessed in PBS. The toxicity effects of all samples were studied using viability assays on human fibroblasts cells (HGF-1) in vitro. The sizes of the crystallites were about 10–70 nm with irregular morphology and present the phase corresponding to the JCPDS card 9–0432 for hydroxyapatite. The results of the toxicity experiments indicated that doped and undoped powders are biocompatible with fibroblasts cells. Hydroxyapatite samples doped with 5% of europium and loaded with 5-fluorouracil release almost 7 mg/L of the drug after 60 minutes in PBS and decrease the viability of HeLa cells after 24 hours. PMID:27965525

  1. Nanostructure of Calcium Silicate Hydrates in Cements

    KAUST Repository

    Skinner, L. B.

    2010-05-11

    Calcium silicate hydrate (CSH) is the major volume phase in the matrix of Portland cement concrete. Total x-ray scattering measurements with synchrotron x rays on synthetic CSH(I) shows nanocrystalline ordering with a particle diameter of 3.5(5) nm, similar to a size-broadened 1.1 nm tobermorite crystal structure. The CSH component in hydrated tricalcium silicate is found to be similar to CSH(I). Only a slight bend and additional disorder within the CaO sheets is required to explain its nanocrystalline structure. © 2010 The American Physical Society.

  2. Real-time in situ monitoring via europium emission of the photo-release of antitumor cisplatin from a Eu-Pt complex.

    Science.gov (United States)

    Li, Hongguang; Lan, Rongfeng; Chan, Chi-Fai; Jiang, Lijun; Dai, Lixiong; Kwong, Daniel W J; Lam, Michael Hon-Wah; Wong, Ka-Leung

    2015-09-25

    A water-soluble light-responsive antitumor agent, PtEuL, based on a cisplatin-linked europium-cyclen complex has been synthesized and evaluated for controlled cisplatin release by linear/two-photon excitation in vitro with concomitant turn-on and long-lived europium emission as a responsive traceable signal.

  3. Stability constants for silicate adsorbed to ferrihydrite

    DEFF Research Database (Denmark)

    Hansen, Hans Christian Bruun; Wetche, T.P.; Raulund-Rasmussen, Karsten

    1994-01-01

    Intrinsic surface acidity constants (K(a1)intr, K(a2)intr) and surface complexation constant for adsorption of orthosilicate onto synthetic ferrihydrite (K(Si) for the complex = FeOSi(OH)3) have been determined from acid/base titrations in 0.001-0.1 m NaClO4 electrolytes and silicate adsorption e...

  4. Combustion synthesis and photoluminescence study of silicate ...

    Indian Academy of Sciences (India)

    Silicate based bioceramics are promising candidates as biomaterials for tissue engineering. The combustion synthesis method provides control on the morphology and particle size of the synthesized material. This paper discusses the combustion synthesis of akermanite (Ca2MgSi2O7 and Sr2MgSi2O7), which has been ...

  5. Europium doping induced symmetry deviation and its impact on the second harmonic generation of doped ZnO nanowires

    Science.gov (United States)

    Dhara, Soumen; Imakita, Kenji; Mizuhata, Minoru; Fujii, Minoru

    2014-06-01

    In this work, we investigated the effects of europium doping on the second harmonic generation (SHG) of ZnO nanowires (NWs). A non-monotonic enhancement in the SHG is observed with the increase of the europium concentration. Maximum SHG is observed from the 1 at.% europium doped ZnO NWs with an enhancement factor of 4.5. To understand the underlying mechanism, the effective second order non-linear coefficient (deff) is calculated from the theoretical fitting with consideration of the absorption effect. Microstructural characterization reveals the structural deformation of the ZnO NWs caused by europium doping. We estimated the deviation in the crystal site symmetry around the Eu3+ ions (defined as the asymmetric factor) from photoluminescence measurement and it is found to be strongly correlated with the calculated deff value. A strong linear dependence between the magnitudes of deff and the asymmetric factor suggests that deviation in the local site symmetry of the ZnO crystal by europium doping could be the most probable origin of the observed large second order non-linearity.

  6. Suppressive effects of a polymer sodium silicate solution on ...

    African Journals Online (AJOL)

    The silicon contents in the roots of the miniature rose treated with polymer sodium silicate were significantly greater than that in plants treated with monomer sodium silicate. In conclusion, the suppressive effects of sodium silicate in the polymer form were confirmed against powdery mildew and root rot diseases of the ...

  7. The role of water in silicate oligomerization reaction

    NARCIS (Netherlands)

    Trinh, T.T.; Jansen, A.P.J.; Santen, R.A.; Meijer, E.J.

    2009-01-01

    The silicate oligomerization reaction is key to sol-gel chemistry and zeolite synthesis. Numerous experimental and theoretical studies have been devoted to investigating the physical chemistry of silicate oligomers in the prenucleation stage of siliceous zeolite formation. Most of the previous

  8. Suppressive effects of a polymer sodium silicate solution on ...

    African Journals Online (AJOL)

    Mohsen

    2015-10-21

    Oct 21, 2015 ... Sodium silicate was dissolved in water in either a monomer form or polymer form; the effects of both forms of sodium silicate aqueous solution on rose powdery mildew and root rot diseases of miniature rose were examined. Both forms of sodium silicate aqueous solution were applied to the roots of the.

  9. Charge growth, dispersion in europium manganite (EuMnO{sub 3-{delta}}) ceramics revealed using opto-impedance probe

    Energy Technology Data Exchange (ETDEWEB)

    Radhakrishnan, S. [Central Electrochemical Research Institute, Karaikudi-630006, T.N. (India); Jagannathan, R., E-mail: jags57_99@yahoo.com [Central Electrochemical Research Institute, Karaikudi-630006, T.N. (India)

    2011-05-19

    Highlights: > In this study, using opto-, magneto-opto impedance techniques, experimental proof for charge growth in europium manganite (EuMnO{sub 3}) near the region of its Neel temperature is presented. > This study gives data related to dielectric properties of europium manganite. > This study may open-up new avenues for investigating the dielectric characteristics of many electronic-ceramics. - Abstract: In this preliminary report, we present the impedance characteristics of poly-crystalline europium manganite, a promising colossal magneto resistance (CMR) system investigated under optical ({approx}5 eV) and magnetic (0.1 T) perturbations yielding some clues on the charge build-up and dispersion processes. This may possibly be resulting from switching between ferromagnetic and anti-ferromagnetic phases through a charge transfer transition mediated process centering Mn{sup 3+/4+} 3d spins thereby meriting a more detailed study correlating with magnetic measurements.

  10. Rapid and accurate tumor-target bio-imaging through specific in vivo biosynthesis of a fluorescent europium complex.

    Science.gov (United States)

    Ye, Jing; Wang, Jianling; Li, Qiwei; Dong, Xiawei; Ge, Wei; Chen, Yun; Jiang, Xuerui; Liu, Hongde; Jiang, Hui; Wang, Xuemei

    2016-04-01

    A new and facile method for rapidly and accurately achieving tumor targeting fluorescent images has been explored using a specifically biosynthesized europium (Eu) complex in vivo and in vitro. It demonstrated that a fluorescent Eu complex could be bio-synthesized through a spontaneous molecular process in cancerous cells and tumors, but not prepared in normal cells and tissues. In addition, the proteomics analyses show that some biological pathways of metabolism, especially for NADPH production and glutamine metabolism, are remarkably affected during the relevant biosynthesis process, where molecular precursors of europium ions are reduced to fluorescent europium complexes inside cancerous cells or tumor tissues. These results proved that the specific self-biosynthesis of a fluorescent Eu complex by cancer cells or tumor tissues can provide a new strategy for accurate diagnosis and treatment strategies in the early stages of cancers and thus is beneficial for realizing precise surgical intervention based on the relevant cheap and readily available agents.

  11. Polystyrene latex particles containing europium complexes prepared by miniemulsion polymerization using bovine serum albumin as a surfactant for biochemical diagnosis.

    Science.gov (United States)

    Aikawa, Tatsuo; Mizuno, Akihiro; Kohri, Michinari; Taniguchi, Tatsuo; Kishikawa, Keiki; Nakahira, Takayuki

    2016-09-01

    Luminescent particles have been attracting significant attention because they can be used in biochemical applications, such as detecting and imaging biomolecules. In this study, luminescent polystyrene latex particles were prepared through miniemulsion polymerization of styrene with dissolved europium complexes in the presence of bovine serum albumin (BSA) and poly(ethylene glycol) monomethoxy methacrylate as surfactants. The solubility of the europium complex in styrene has a strong effect on the yield of the particle. Europium tris(2-thenoyl trifluoroacetonate) di(tri-n-octyl phosphine oxide), which has a high solubility in styrene, was sufficiently incorporated into the polystyrene particles compared to europium tris(2-thenoyl trifluoroacetonate), which has a low solubility in styrene. The luminescence property of the europium complex could remain intact even after its incorporation through the miniemulsion polymerization. In the aqueous dispersion, the resulting particles could emit strong luminescence, which is a characteristic of the europium complex. The antibody fragments were covalently attached to BSA-covered particles after a reaction with a bifunctional linker, N-(6-maleimidocaproyloxy)succinimide. The time-resolved fluoroimmunoassay technique showed that 3.3pg/mL of human α-fetoproteins (AFP) can be detected by using the resulting luminescent particles. An immunochromatographic assay using the resulting particles was also performed as a convenient method to qualitatively detect biomolecules. The detection limit of AFP measured by the immunochromatographic assay was determined to be 2000pg/mL. These results revealed that the luminescent particles obtained in this study can be utilized for the highly sensitive detection of biomolecules and in vitro biochemical diagnosis. Copyright © 2016 Elsevier B.V. All rights reserved.

  12. Highly specific ''sensing'' of tryptophan by a luminescent europium(III) complex

    Energy Technology Data Exchange (ETDEWEB)

    Stubenrauch, Jan A.; Mevissen, Christian; Schulte, Marie F.; Bochenek, Steffen; Albrecht, Markus [RWTH Univ. Aachen (Germany). Inst. fuer Organische Chemie; Subramanian, Palani S. [Central Salt and Marine Chemicals, Research Institute (CSRI), Gujarat (India)

    2016-07-01

    The europium(III) complex 1-Cl{sub 3} (S,S-2,2{sup '}-(((1,10-phenanthroline-2,9-diyl)bis(methanylylidene))bis (azanylyliden e))bis(3-methylbutanamide)europiumtrichloride) undergoes, only in the presence of the amino acid tryptophan, a change of emission at 615 nm. In the presence of few equivalents of tryptophan, emission of the europium complex is enhanced while it disappears upon addition of large amounts. This behavior can be assigned to displacement of the sensitizing phenanthroline ligand of 1-Cl{sub 2} x Trp in the latter case.

  13. Electron-induced desorption of europium atoms from oxidized tungsten surface: concentration dependence of low-energy peak

    CERN Document Server

    Davydov, S Y

    2002-01-01

    One discusses nature of electron induced desorption of Eu sup 0 europium atoms under E sub e irradiating electron low-energies (approx 30 eV) and peculiarities of yield dependence of Eu sup 0 atoms on their concentration at oxidized tungsten surface. Primary act of vacancy origination in europium adatom inner 5p-shell turned to be the determining stage. Evaluations have shown that just the first of two possible scenarios of ionization (electron intra-atomic to Eu adatom external quasi-level or realise of knocked out electron into vacuum) leads to Eu sup 0 desorption. One determined concentration threshold for yield of Eu sup 0 atoms

  14. Optical properties of europium(III) {beta}-diketonate/polymer-doped systems using supercritical carbon dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Gerasimova, V.I., E-mail: vis@srd.sinp.msu.ru [Skobel' tsyn Research Institute of Nuclear Physics, Moscow State University, Leninskie Gory 1-2, GSP-1, 119991 Moscow (Russian Federation); Antoshkov, A.A.; Zavorotny, Yu.S.; Rybaltovskii, A.O. [Skobel' tsyn Research Institute of Nuclear Physics, Moscow State University, Leninskie Gory 1-2, GSP-1, 119991 Moscow (Russian Federation); Lemenovskii, D.A., E-mail: dali@org.chem.msu.ru [Chemistry Department, Moscow State University, Leninskie Gory 1-3, GSP-1, 119991 Moscow (Russian Federation)

    2013-02-15

    The optical properties of fluoropolymers and polypropylene doped with europium(III) {beta}-diketonates Eu(L){sub 3}{center_dot}2H{sub 2}O and Eu(L){sub 3}phen (L: fod=6,6,7,7,8,8,8-heptafluoro-2,2-dimethyl-3,5-octanedionato, bta=4,4,4-trifluoro-1-phenyl-1,3-butanedione, tta=4,4,4-trifluoro-1-(2-thienyl)-1,3-butanedione, and phen=1,10-phenanthroline) using supercritical carbon dioxide were investigated by absorption and emission spectra. A comparative analysis of the PL decay times of Eu{sup 3+} ions in the initial europium (III) {beta}-diketonates and impregnated fluoropolymers was carried out. The supercritical fluid (SCF) impregnation of polymer samples with europium(III) {beta}-diketonates containing 1,10-phenanthroline was found to be obstructed differently depending on the type of ligand in the entire investigated impregnation temperature range (T{sub SCF}=50-90 Degree-Sign S). It is shown that from the variety of Eu(L){sub 3}phen only Eu(fod){sub 3}phen can be introduced into the polymer matrix by this method. - Highlights: Black-Right-Pointing-Pointer The optical properties of polymers doped with Eu{sup 3+} {beta}-diketonates using SC CO{sub 2} were investigated. Black-Right-Pointing-Pointer A comparative analysis of the PL decay times in the initial Eu{sup 3+} {beta}-diketonates and doped polymers was carried out. Black-Right-Pointing-Pointer The SC CO{sub 2} impregnation of polymers with Eu{sup 3+} {beta}-diketonates containing 1,10-phenanthroline was found to be obstructed.

  15. Reverse lyotropic liquid crystals from europium nitrate and P123 with enhanced luminescence efficiency.

    Science.gov (United States)

    Yi, Sijing; Li, Qintang; Liu, Hongguo; Chen, Xiao

    2014-10-02

    Fabrication of lyotropic aggregates containing the lanthanide ions is becoming a preferable way to prepare novel functional materials. Here, the lyotropic liquid crystals (LLCs) of reverse hexagonal, reverse bicontinuous cubic, and lamellar phases have been constructed in sequence directly from the mixtures of Eu(NO3)3·6H2O and Pluronic P123 amphiphilc block copolymer with increasing the salt proportion. Their phase types and structural characteristics were analyzed using polarized optical microscopy (POM) and small-angle X-ray scattering (SAXS) measurements. The driving forces of reverse LLC phase formation were investigated using Fourier-transformed infrared spectroscopy (FTIR) and rheological measurements. The hydrated europium salt was found to act not only as a solvent here, but also as the bridge to form hydrogen bonding between coordinated water molecules and PEO blocks, which played a key role in the reverse LLCs formation. Compared to those in aqueous solutions and solid state, the enhanced luminescence quantum yields and prolonged excited state lifetimes were observed in two europium containing reverse mesophases. The luminescence quenching effect of lanthanide ions was efficiently suppressed, probably due to the substitution of coordinated water molecules by oxyethyl groups of P123 and ordered phase structures of LLCs, where the coordinated europium ions were confined and isolated by PEO blocks. The optimum luminescence performance was then found to exist in the reverse hexagonal phase. The obtained results on such lanthanide-induced reverse LLCs should be referable for designing new luminescent soft materials construction to expand their application fields.

  16. How Do Radionuclides Accumulate in Marine Organisms? A Case Study of Europium with Aplysina cavernicola.

    Science.gov (United States)

    Maloubier, Melody; Shuh, David K; Minasian, Stefan G; Pacold, Joseph I; Solari, Pier-Lorenzo; Michel, Hervé; Oberhaensli, François R; Bottein, Yasmine; Monfort, Marguerite; Moulin, Christophe; Den Auwer, Christophe

    2016-10-04

    In the ocean, complex interactions between natural and anthropogenic radionuclides, seawater, and diverse marine biota provide a unique window through which to examine ecosystem and trophic transfer mechanisms in cases of accidental dissemination. The nature of interaction between radionuclides, the marine environment, and marine species is therefore essential for better understanding transfer mechanisms from the hydrosphere to the biosphere. Although data pertaining to the rate of global transfer are often available, little is known regarding the mechanism of environmental transport and uptake of heavy radionuclides by marine species. Among marine species, sponges are immobile active filter feeders and have been identified as hyperaccumulators of several heavy metals. We have selected the Mediterranean sponge Aplysina cavernicola as a model species for this study. Actinide elements are not the only source of radioactive release in cases of civilian nuclear events; however, their physicochemical transfer mechanisms to marine species remain largely unknown. We have targeted europium(III) as a representative of the trivalent actinides such as americium or curium. To unravel biological uptake mechanisms of europium in A. cavernicola, we have combined radiometric (γ) measurements with spectroscopic (time-resolved laser-induced fluorescence spectroscopy, TRLIFS, and X-ray absorption near-edge structure, XANES) and imaging (transmission electron microscopy, TEM, and scanning transmission X-ray microscopy, STXM) techniques. We have observed that the colloids of NaEu(CO3)2·nH2O formed in seawater are taken up by A. cavernicola with no evidence that lethal dose has been reached in our working conditions. Spectroscopic results suggest that there is no change of speciation during uptake. Finally, TEM and STXM images recorded at different locations across a sponge cross section, together with differential cell separation, indicate the presence of europium particles (around

  17. Trace electrochemical analysis of Europium, Ytterbium, and Cerium at their joint presence in solution

    Directory of Open Access Journals (Sweden)

    Rema Matakova

    2012-03-01

    Full Text Available In the course of several decades at the department of analytical chemistry and chemistry of rare elements there were studied the electrode processes with participation of rare-earth metals (REM in accordance with the long awaiting problem of the development of rare-metal and rare-earth branch of non-ferrous metallurgy of Kazakhstan. With the aim of express and highly sensitive analytical control of raw materials and final product of rare-earth industry there were developed the methods of inversion-voltamperometric determination of low concentrations of europium, ytterbium and cerium under the conditions of their individual and combined presence in the solution.

  18. Synergistic extraction of europium and americium into nitrobenzene by using hydrogen dicarbollylcobaltate and dodecaethylene glycol.

    Science.gov (United States)

    Makrlík, Emanuel; Vaňura, Petr; Selucký, Pavel

    2013-01-01

    Extraction of microamounts of europium and americium by a nitrobenzene solution of hydrogen dicarbollylcobaltate (H+B-) in the presence of dodecaethylene glycol (DDEG, L) has been investigated. The equilibrium data have been explained assuming that the species HL+, H2L2+, ML3+ and MH-1L2+ (M3+ = Eu3+, Am3+; L = DDEG) are extracted into the organic phase. The values of extraction and stability constants of the complex species in nitrobenzene saturated with water have been determined. It was found that in this nitrobenzene medium, the stability constant of the EuL3+ complex is comparable with that of AmL3+.

  19. Red/blue electroluminescence from europium-doped organic light emitting diodes

    Science.gov (United States)

    Hagen, Joshua A.; Li, Wayne X.; Grote, James G.; Steckl, Andrew J.

    2006-02-01

    Red/Blue emitting organic light emitting diodes (OLED) devices have been obtained using a Europium-doped organic emitting layer (NPB:Eu). The Eu-doped OLEDs emit in 2 color ranges: a broad blue (~420-500nm) band due to NPB emission and a narrow red peak at 620nm due to Eu emission. The red/blue devices achieve a brightness ~13x more intense than a similarly structured green (Alq 3) emitting OLED. These NPB:Eu emitting structures also reach a maximum efficiency of 0.2 cd/A at brightnesses above 100 cd/m2.

  20. New Class of Bright and Highly Stable Chiral Cyclen Europium Complexes for Circularly Polarized Luminescence Applications.

    Science.gov (United States)

    Dai, Lixiong; Lo, Wai-Sum; Coates, Ian D; Pal, Robert; Law, Ga-Lai

    2016-09-06

    High glum values of +0.30 (ΔJ = 1, 591 nm, in DMSO) and -0.23 (ΔJ = 1, 589 nm, in H2O) were recorded in our series of newly designed macrocyclic europium(III) complexes. A sterically locking approach involving a bidentate chromophore is adopted to control the formation of one stereoisomer, giving rise to extreme rigidity, high stability, and high emission intensity. The combination of a chiral substituent on a macrocyclic chelate for lanthanide ions opens up new perspectives for the further development of circulary polarized luminescent chiral tags in optical and bioapplications.

  1. A microemulsion preparation of nanoparticles of europium in silica with luminescence enhancement using silver

    Science.gov (United States)

    Ma, Zhi Ya; Dosev, Dosi; Kennedy, Ian M

    2010-01-01

    A facile one-pot microemulsion method has been developed for the synthesis of spherical silver core–silica shell (Ag@SiO2) nanoparticles with europium chelates doped in the shell through a silane agent. The method is significantly more straightforward than other extant methods. Measurements of the luminescent emissions from the Ag@SiO2 nanoparticles, in comparison with control silica nanoparticles without silver cores, showed that the presence of the silver cores can increase the fluorescence intensity approximately 24-fold and decrease the luminescence lifetime. This enhancement offers a potential increase in overall particle detectability with increased fluorophore photostability. PMID:19417456

  2. Metal Controlled Diastereoselective Self-assembly and Circularly Polarized Luminescence of a Chiral Heptanuclear Europium Wheel

    Science.gov (United States)

    Bozoklu, Gülay; Gateau, Christelle; Imbert, Daniel; Pécaut, Jacques; Robeyns, Koen; Filinchuk, Yaroslav; Memon, Farah; Muller, Gilles

    2012-01-01

    The chiral dissymmetric tetradentate ligand SPhbipox (6’-(4-phenyloxazolin-2-yl)-2,2’-bipyridine-6-carboxylic acid) leads to the diastereoselective assembly of a homochiral Eu(III) triangle and of a highly emissive (QY=27%) heptanuclear wheel which is the largest example of chiral luminescent complex of Eu(III) reported to date. We show that the nuclearity of the assembly is controlled by the solvent and the europium cation. All the compounds show large circularly polarized luminescence with an activity which varies with the nature of the assembly (highest for the homochiral trimer). PMID:22548280

  3. A europium(III)-based PARACEST agent for sensing singlet oxygen by MRI

    Science.gov (United States)

    Song, Bo; Wu, Yunkou; Yu, Mengxiao; Zhao, Piyu; Zhou, Cheng; Kiefer, Garry E.

    2013-01-01

    A europium (III) DOTA-tetraamide complex was designed as a MRI sensor of singlet oxygen (1O2). The water soluble, thermodynamically stable complex reacts rapidly with 1O2 to form an endoperoxide derivative that results in an ∼3 ppm shift in the position of the Eu(III)-bound water chemical exchange saturation transfer (CEST) peak. The potential of using this probe to detect accumulation of the endoperoxide derivative in biological media by ratiometric CEST imaging was demonstrated. PMID:23575743

  4. Silicate release from glass for pharmaceutical preparations.

    Science.gov (United States)

    Bohrer, Denise; Bortoluzzi, Fabiana; Nascimento, Paulo Cícero; Carvalho, Leandro Machado; Ramirez, Adrian Gustavo

    2008-05-01

    Glass is made of polymeric silica and other minor components, which are necessary for turning the silica into a material more easily moldable and resistant to temperature changes. Glass containers for pharmaceutical usage are classified according to their resistance to a chemical attack, a test carried out in the presence of water and heat. The test is designed to show the released alkalinity, a variable dependent on the amount of sodium oxide, one of the minor components added to the glass mass. In this work, the release of silica from glass by action of constituents from pharmaceutical formulations was investigated. The study included products used in large volumes and usually stored in glass containers. Solutions of amino acids, electrolytes, glucose, oligoelements and others such as heparin and sodium bicarbonate were individually stored in glass containers and heated at 121 degrees C for 30min, as in the water attack test. The test was also carried out only with water, where the pH varied from 2 to 12. The released silicate was measured either by photometry or atomic absorption spectrometry, depending on the nature of the sample. The results showed that silicate is released during the heating cycle even if the contact is with pure water only. The pH exerts a considerable influence on the release, being that the higher the pH, the higher the silica dissolved. An elevated pH, however, is not the only factor responsible for silica dissolution. While in the solutions of NaCl, KCl, Mg Cl2 and ZnSO4 and in most of the amino acids, the concentration of silicate was as high as in pure water (0.1-1.0mg Si/L). In the solutions of sodium acetate, bicarbonate and gluconate, its concentration was much higher, over 30mg Si/L. These results were confirmed by the analysis of commercial products, where in solutions of amino acids the level of silicate ranged from 0.14 to 0.19mg Si/L. On the other hand, calcium gluconate, sodium bicarbonate and potassium phosphate presented

  5. Synthesis and Characterisation of the Europium (III Dimolybdo-Enneatungsto-Silicate Dimer, [Eu(α-SiW9Mo2O392]13−

    Directory of Open Access Journals (Sweden)

    Loïc Parent

    2015-07-01

    Full Text Available The chemistry of polyoxometalates (POMs keeps drawing the attention of researchers, since they constitute a family of discrete molecular entities whose features may be easily modulated. Often considered soluble molecular oxide analogues, POMs possess enormous potential due to a myriad of choices concerning size, shape and chemical composition that may be tailored in order to fine-tune their physico-chemical properties. Thanks to the recent progress in single-crystal X ray diffraction, new POMs exhibiting diverse and unexpected structures have been regularly reported and described. We find it relevant to systematically analyse the different equilibria that govern the formation of POMs, in order to be able to establish reliable synthesis protocols leading to new molecules. In this context, we have been able to synthesise the Eu3+-containing silico-molybdo-tungstic dimer, [Eu(α-SiW9Mo2O392]13−. We describe the synthesis and characterisation of this new species by several physico-chemical methods, such as single-crystal X-ray diffraction, 183W NMR and electrochemistry.

  6. Neutron and Charged-Particle Induced Cross Sections for Radiochemistry in the Region of Samarium, Europium, and Gadolinium

    Energy Technology Data Exchange (ETDEWEB)

    Hoffman, R D; Kelley, K; Dietrich, F S; Bauer, R; Mustafa, M

    2004-11-30

    We have developed a set of modeled nuclear reaction cross sections for use in radiochemical diagnostics. Systematics for the input parameters required by the Hauser-Feshbach statistical model were developed and used to calculate neutron and proton induced nuclear reaction cross sections in the mass region of samarium, europium and gadolinium (62 {le} Z {le} 64, 82 {le} N {le} 96).

  7. Colloidal europium nanoparticles via a solvated metal atom dispersion approach and their surface enhanced Raman scattering studies.

    Science.gov (United States)

    Urumese, Ancila; Jenjeti, Ramesh Naidu; Sampath, S; Jagirdar, Balaji R

    2016-08-15

    Chemistry of lanthanide metals in their zerovalent state at the nanoscale remains unexplored due to the high chemical reactivity and difficulty in synthesizing nanoparticles by conventional reduction methods. In the present study, europium(0) nanoparticles, the most reactive of all the rare earth metals have been synthesized by solvated metal atom dispersion (SMAD) method using hexadecyl amine as the capping agent. The as-prepared europium nanoparticles show surface Plasmon resonance (SPR) band in the visible region of the electromagnetic spectrum. This lead to the investigation of its surface enhanced Raman scattering (SERS) using visible light excitation source. The SERS activity of europium nanoparticles has been followed using 4-aminothiophenol and biologically important molecules such as hemoglobin and Cyt-c as the analytes. This is the first example of lanthanide metal nanoparticles as SERS substrate which can possibly be extended to other rare-earth metals. Since hemoglobin absorbs in the visible region, the use of visible light excitation source leads to surface enhanced resonance Raman spectroscopy (SERRS). The interaction of biomolecules with Eu(0) has been followed using FT-IR and UV-visible spectroscopy techniques. The results indicate that there is no major irreversible change in the structure of biomolecules upon interaction with europium nanoparticles. Copyright © 2016 Elsevier Inc. All rights reserved.

  8. Rapid screening of oxytetracycline residue in catfish muscle by dispersive liquid-liquid microextraction and europium-sensitized luminescence

    Science.gov (United States)

    Oxytetracycline (OTC) residue in catfish muscle was screened by dispersive liquid-liquid microextraction (DLLME) and europium-sensitized luminescence (ESL). After extraction in EDTA, HCl, and acetonitrile, cleanup was carried out by DLLME, and ESL was measured at microgram = 385 nm and wavelength = ...

  9. Luminescence variations in europium-doped silicon-substituted hydroxyapatite nanobiophosphor via three different methods

    Energy Technology Data Exchange (ETDEWEB)

    Thang, Cao Xuan; Pham, Vuong-Hung, E-mail: vuong.phamhung@hust.edu.vn

    2015-07-15

    Highlights: • Europium doped silicon-substituted hydroxyapatite was synthesized by wet chemical synthesis method. • Morphology of nanoparticles depended on the synthesized method. • Photoluminescence intensity of the sample increases with the increasing of Si substitutions, Eu dopants and thermal annealing. - Abstract: This paper reports the first attempt for the synthesis of europium-doped Si-substituted hydroxyapatite (HA) nanostructure to achieve strong and stable luminescence of nanobiophosphor, particularly, by addition of different Eu dopants, Si substitutions, and application of optimum annealing temperatures of up to 1000 °C. The nanobiophosphor was synthesized by the coprecipitation, microwave, and hydrothermal methods. The nanoparticles demonstrated a nanowire to a spindle-like morphology, which was dependent on the method of synthesis. The photoluminescence (PL) intensity of the sample increases with the increase in Si substitutions and Eu dopants. The luminescent nanoparticles also showed the typical luminescence of Eu{sup 3+} centered at 610 nm, which was more efficient for the annealed Eu-doped Si-HA nanoparticles than for the as-synthesized nanoparticles. Among the different synthesis methods, the hydrothermal method reveals the best light emission represented by high PL intensity and narrow PL spectra. These results suggest the potential application of Eu-doped Si-HA in stable and biocompatible nanophosphors for light emission and nanomedicine.

  10. Resonance ionization spectroscopy of Europium The first application of the PISA at ISOLDE-RILIS

    CERN Document Server

    AUTHOR|(CDS)2099873; Marsh, Bruce Alan

    The following work has been carried out at the radioactive ion beam facility ISOLDE at CERN. A compact atomic beam unit named PISA (Photo Ionization Spectroscopy Apparatus) has been implemented as a recent addition to the laboratory of the Resonance Ionization Laser Ion Source (RILIS). The scope of this thesis work was to demonstrate different applications of the PISA, using the existing and highly developed laser setup of the RILIS installation. In a demonstration of the suitability of PISA for ionization scheme development, a new ionization scheme for Europium has been developed. This resulted in the observation of several new autoionizing states and Rydberg series. Through the analysis of the observed Rydberg resonances a refined value of $45734.33(3)(3)$ cm$^{-1}$ for the ionization potential of the europium atom has been determined. In addition this thesis reports on the feasibility of the use of the PISA as a RILIS performance monitoring device during laser ion source operations. Finally the present wor...

  11. Structural and electrical properties of the europium-doped indium zinc oxide thin film transistors

    Energy Technology Data Exchange (ETDEWEB)

    Ting, Chu-Chi, E-mail: ccting@ccu.edu.tw [Graduate Institute of Opto-Mechatronics Engineering, National Chung Cheng University, 168 University Rd., Min-Hsiung, Chia-Yi, Taiwan, ROC (China); Advanced Institute for Manufacturing with High-Tech Innovations, National Chung Cheng University, 168 University Rd., Min-Hsiung, Chia-Yi, Taiwan, ROC (China); Li, Wei-Yang; Wang, Ching-Hua; Yong, Hua-En [Graduate Institute of Opto-Mechatronics Engineering, National Chung Cheng University, 168 University Rd., Min-Hsiung, Chia-Yi, Taiwan, ROC (China)

    2014-07-01

    The EuInZnO (EIZO) thin film transistor (TFT) devices were fabricated by the sol–gel spin-coating technique. The EIZO TFT operates in the n-channel depletion mode and exhibits a well-defined pinch-off and saturation region. Because europium ion possesses lower electronegativity (1.2) and standard electrode potential (− 1.991 V), it can act as the carrier suppressor to reduce the carrier concentrations of the IZO (In:Zn = 1:1) thin film. Eu{sup 3+} (13 mol%)-doped IZO TFT possesses the optimum performance, and its field-effect mobility in the saturated regime, threshold voltage, on–off ratio, and S-factor are 1.23 cm{sup 2}/Vs, 3.28 V, 1.07 × 10{sup 6}, and 2.28 V/decade, respectively. - Highlights: • Europium ions can act as the carrier suppressor in the InZnO system. • The EuInZnO forms an n-channel material for the thin film transistor (TFT) device. • The optimum performance of the EuInZnO TFT is the sample with 13 mol% Eu{sup 3+} doping.

  12. Europium phosphomolybdate and osmium metallopolymer multi-functional LbL films: redox and electrocatalytic properties.

    Science.gov (United States)

    Fernandes, Diana M; Vos, Johannes G; Freire, Cristina

    2014-04-15

    Hybrid multilayer films composed by osmium metallopolymer [Os(bpy)2(PVP)10Cl]Cl (Os-poly) and europium phosphomolybdate, K₁₁[Eu(III)(PMo₁₁O₃₉)₂] (Eu(PMo11)2), were prepared using the electrostatic layer-by-layer (LbL) self-assembly method. The film build-up, monitored by electronic spectroscopy, showed a regular stepwise growth indicating a strong interaction between layers. The XPS measurements corroborated the successful fabrication of the hybrid films with the Os-poly/Eu(PMo11)2 composition. SEM images revealed a completely covered surface with a highly roughened texture. Electrochemical characterisation of films by cyclic voltammetry revealed three Mo-based reduction processes (Mo(VI)→Mo(V)) in the potential range between -0.4 and 0.1 V and one Os reduction process (Os(III)→Os(II)) at ≈0.270 V. The cyclic voltammograms of two electroactive probes, [Fe(CN)₆](3-/4-) and [Ru(NH₃)₆](3+/2+) on {Os-poly/Eu(PMo11)2}n modified electrodes revealed redox mediation between film and the probes. Furthermore, the {Os-poly/Eu(PMo11)2}n multilayer films also showed excellent Mo-based electrocatalytic activity towards reduction of nitrite and iodate, confirming the multi-functional properties of the hybrid europium phosphomolybdate - osmium metallopolymer LbL films. Copyright © 2014 Elsevier Inc. All rights reserved.

  13. Theoretical spectroscopic study of the conjugate microcystin-LR-europium cryptate

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Julio G.; Dutra, Jose Diogo L.; Costa Junior, Nivan B. da; Freire, Ricardo O., E-mail: rfreire@ufs.br [Universidade Federal de Sergipe (UFS), Sao Cristovao, SE (Brazil). Departamento de Quimica; Alves Junior, Severino; Sa, Gilberto F. de [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Departamento de Quimica Fundamental

    2013-02-15

    In this work, theoretical tools were used to study spectroscopic properties of the conjugate microcystin-LR-europium cryptate. The Sparkle/AM1 model was applied to predict the geometry of the system and the INDO/S-CIS model was used to calculate the excited state energies. Based on the Judd-Ofelt theory, the intensity parameters were predicted and a theoretical model based on the theory of the 4f-4f transitions was applied to calculate energy transfer and backtransfer rates, radiative and non-radiative decay rates, quantum efficiency and quantum yield. A detailed study of the luminescent properties of the conjugate Microcystin-LR-europium cryptate was carried out. The results show that the theoretical quantum yield of luminescence of 23% is in good agreement with the experimental value published. This fact suggests that this theoretical protocol can be used to design new systems in order to improve their luminescence properties. The results suggest that this luminescent system may be a good conjugate for using in assay ELISA for detection by luminescence of the Microcystin-LR in water. (author)

  14. pH-controlled delivery of luminescent europium coated nanoparticles into platelets

    Science.gov (United States)

    Davies, Amy; Lewis, David J.; Watson, Stephen P.; Thomas, Steven G.; Pikramenou, Zoe

    2012-01-01

    Water soluble, luminescent gold nanoparticles are delivered into human platelets via a rapid, pH-controlled mechanism using a pH low insertion peptide, pHLIP. The approach introduces cocoating of gold nanoparticles with a europium luminescent complex, EuL and the pHLIP peptide to give pHLIP•EuL•Au. The 13-nm diameter gold nanoparticles act as a scaffold for the attachment of both the luminescent probe and the peptide to target delivery. Their size allows delivery of approximately 640 lanthanide probes per nanoparticle to be internalized in human platelets, which are not susceptible to transfection or microinjection. The internalization of pHLIP•EuL•Au in platelets, which takes just minutes, was studied with a variety of imaging modalities including luminescence, confocal reflection, and transmission electron microscopy. The results show that pHLIP•EuL•Au only enters the platelets in low pH conditions, pH 6.5, mediated by the pHLIP translocation across the membrane, and not at pH 7.4. Luminescence microscopy images of the treated platelets show clearly the red luminescence signal from the europium probe and confocal reflection microscopy confirms the presence of the gold particles. Furthermore, transmission electron microscopy gives a detailed insight of the internalization and spatial localization of the gold nanoparticles in the platelets. Thus, we demonstrate the potential of the design to translocate multimodal nanoparticle probes into cells in a pH dependent manner. PMID:22308346

  15. Analysis of metal surfaces coated with europium-doped titanium dioxide by laser induced breakdown spectroscopy.

    Science.gov (United States)

    Głogocka, Daria; Noculak, Agnieszka; Pucińska, Joanna; Jopek, Wojciech; Podbielska, Halina; Langner, Marek; Przybyło, Magdalena

    2015-01-01

    The surface passivation with titanium sol-gel coatings is a frequently used technique to control the adsorption of selected biological macromolecules and to reduce the exposure of the bulk material to biological matter. Due to the increasing number of new coating-preparation methods and new gel compositions with various types of additives, the quality and homogeneity determination of the surface covering is a critical factor affecting performance of any implanted material. While coating thickness is easy to determine, the homogeneity of the surface distribution of coating materials requires more elaborate methodologies. In the paper, the laser induced breakdown spectroscopy (LIBS) based method, capable to quantitate the homogeneity and uniformity of the europium in titanium dioxide sol-gel coatings on stainless steel surfaces prepared with two different procedures: spin-coating and dip-coating, is presented. The emission intensity of titanium has been used to determine the coating thickness whereas the relative values of europium and titanium emission intensities provide data on the coating homogeneity. The obtained results show that the spin-coating technique provides better surface coverage with titanium dioxide. However, when the surface coating compositions were compared the dip-coating technique was more reliable.

  16. Europium(III) Macrocyclic Complexes with Alcohol Pendant Groups as Chemical Exchange Saturation Transfer Agents

    Science.gov (United States)

    Woods, Mark; Woessner, Donald E.; Zhao, Piyu; Pasha, Azhar; Yang, Meng-Yin; Huang, Ching-Hui; Vasalitiy, Olga; Morrow, Janet R.; Sherry, A. Dean

    2009-01-01

    Paramagnetic lanthanide(III) complexes that contain hyperfine-shifted exchangeable protons offer considerable advantages over diamagnetic molecules as chemical exchange saturation transfer (CEST) agents for MRI. As part of a program to investigate avenues to improve the sensitivity of such agents, the CEST characteristics of europium(III) macrocyclic complexes having appended hydroxyethyl groups were investigated. The CEST spectrum of the asymmetrical complex, EuCNPHC3+, shows five distinct peaks for each magnetically nonequivalent exchangeable proton in the molecule. The CEST spectra of this complex were fitted to NMR Bloch theory to yield exchange rates between each of six exchanging proton pools (five on the agent plus bulk water). Exchange between the Eu3+-bound hydroxyl protons and bulk water protons was slow in dry acetonitrile but accelerated incrementally upon stepwise addition of water. In pure water, exchange was too fast to observe a CEST effect. The utility of this class of europium(III) complex for CEST imaging applications is ultimately limited by the small chemical shifts induced by the hydroxyl-appended ligands of this type and the resulting small Δω values for the exchangeable hydroxyl protons. PMID:16881645

  17. Red light emission from europium doped zinc sodium bismuth borate glasses

    Science.gov (United States)

    Hegde, Vinod; Viswanath, C. S. Dwaraka; Upadhyaya, Vyasa; Mahato, K. K.; Kamath, Sudha D.

    2017-12-01

    Zinc sodium bismuth borate (ZNBB) glasses doped with different concentrations of europium were prepared by conventional melt quenching method and characterized through the measurements of density, refractive index, X-ray diffraction (XRD), Fourier Transform Infrared (FTIR) spectra, optical absorption, luminescence and radiative lifetimes. FTIR spectra showed seven characteristic peaks of bismuth and borate functional groups in the range of 400-1600 cm-1. The optical band gap and bonding parameters have been calculated from absorption spectra. Photoluminescence spectra recorded in the visible region with 394 nm excitation are used to calculate the Judd-Ofelt (JO) intensity parameters (Ω2 and Ω4). The JO intensity parameters have been used to calculate the radiative parameters such as branching ratio (β), stimulated emission cross-section (σse), transition probability (A) for the fluorescent level of 5D0→7F2. Decay rates through single exponential are used to calculate the lifetime (τm) of the meta-stable state 5D0 of (Eu3+ ion) these glasses. The radiative parameters measured for all these glasses show 0.7 mol% europium doped zinc sodium bismuth borate glass 5D0→7F2 transition has the potential for red laser applications. The quality of the colour emitted by the present glasses are estimated quantitatively by CIE chromaticity coordinates, which confirms the suitability of these glasses as a red emitting material for field emission technologies and LEDs.

  18. Samarium-153 EDTMP for metastatic bone pain palliation: the impact of europium impurities.

    Science.gov (United States)

    Kalef-Ezra, J A; Valakis, S T; Pallada, S

    2015-02-01

    To evaluate the impact on the radiation protection policies of the radiocontaminants in Samarium-153 ethylenediamine tetramethylene phosphonate ((153)Sm-EDTMP). The internal contamination of patients treated with (153)Sm-EDMTP for palliation of painful disseminated multiple bone metastases due to long-lived impurities was assessed by direct measurements. These measurements were coupled with dose-rate measurements close to their bodies and spectroscopic analysis of the residual activity in post-treatment radiopharmaceutical vials. Whole-body counting carried out in six patients showed a 30-81-kBq europium -152 plus europium-154 contamination. The 0.85 mean (152)Eu- to -(154)Eu activity ratio obtained by direct counting was similar to that assessed by analysis of post-treatment residual activities in twelve radiopharmaceutical vials following radiopharmaceutical injection. The long-lived radiocontaminants in the patient's bodies and the treatment wastes require modifications of the applicable radiation protection policies. Copyright © 2014 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

  19. Induced Europium Circularly Polarized Luminescence Monitors Reversible Drug Binding to Native α1 -Acid Glycoprotein.

    Science.gov (United States)

    Jennings, Laura; Waters, Ryan S; Pal, Robert; Parker, David

    2017-02-03

    Alpha-1-acid glycoprotein (α1 -AGP) is an important blood plasma glycoprotein. Following an acute-phase reaction such as stress, inflammation, burn, or infection, the bloodstream concentration of α1 -AGP can increase up to 400 % of its normal concentration. A wide range of drugs is known to bind α1 -AGP. Increased binding of pharmacologically active compounds to α1 -AGP moderates their clinical effect by decreasing the amount of unbound drug in the bloodstream. This has important clinical ramifications for such applications as the duration of anesthesia and in determining dosage for drug therapy. In this study, the competitive binding to α1 -AGP of a dynamically racemic europium(III) complex with seven pharmacologically active drugs absorbing in the range λ 250-290 nm was monitored by following changes in europium total emission and in induced circularly polarized luminescence (CPL). Binding affinities corresponding to Kd values in the range 0.5-100 μm were measured, in good agreement with published data. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Europium-doped amorphous calcium phosphate porous nanospheres: preparation and application as luminescent drug carriers

    Directory of Open Access Journals (Sweden)

    Zhang Kui-Hua

    2011-01-01

    Full Text Available Abstract Calcium phosphate is the most important inorganic constituent of biological tissues, and synthetic calcium phosphate has been widely used as biomaterials. In this study, a facile method has been developed for the fabrication of amorphous calcium phosphate (ACP/polylactide-block-monomethoxy(polyethyleneglycol hybrid nanoparticles and ACP porous nanospheres. Europium-doping is performed to enable photoluminescence (PL function of ACP porous nanospheres. A high specific surface area of the europium-doped ACP (Eu3+:ACP porous nanospheres is achieved (126.7 m2/g. PL properties of Eu3+:ACP porous nanospheres are investigated, and the most intense peak at 612 nm is observed at 5 mol% Eu3+ doping. In vitro cytotoxicity experiments indicate that the as-prepared Eu3+:ACP porous nanospheres are biocompatible. In vitro drug release experiments indicate that the ibuprofen-loaded Eu3+:ACP porous nanospheres show a slow and sustained drug release in simulated body fluid. We have found that the cumulative amount of released drug has a linear relationship with the natural logarithm of release time (ln(t. The Eu3+:ACP porous nanospheres are bioactive, and can transform to hydroxyapatite during drug release. The PL properties of drug-loaded nanocarriers before and after drug release are also investigated.

  1. LABORATORY INVESTIGATIONS OF SILICATE MUD CONTAMINATION WITH CALCIUM

    Directory of Open Access Journals (Sweden)

    Nediljka Gaurina-Međimurec

    2004-12-01

    Full Text Available The silicate-based drilling fluid is a low solids KCl/polymer system with the addition of soluble sodium or potassium silicate to enhance inhibition and wellbore stability. Silicate-based drilling fluids exhibit remarkable shale and chalk stabilizing properties, resulting in gauge hole and the formation of firm cuttings when drilling reactive shales and soft chalks. Silicates protect shales by in-situ gellation when exposed to the neutral pore fluid and precipitation, which occurs on contact with divalent ions present at the surface of the shale. Also, silicates prevent the dispersion and washouts when drilling soft chalk by reacting with the Ca2+ ions present on chalk surfaces of cutting and wellbore to form a protective film. The silicate-based drilling fluid can be used during drilling hole section through shale interbeded anhydrite formations because of its superior shale stabilizing characteristics. However, drilling through the anhydrite can decrease the silicate concentration and change rheological and filtration fluid properties. So, the critical concentration of calcium ions should be investigated by lab tests. This paper details the mechanism of shale inhibition using silicate-based drilling fluid, and presents results of lab tests conducted to ascertain the effect of Ca2+ ions on silicate level in the fluid and the fluid properties.

  2. "Rigid" Luminescent Soft Materials: Europium-Containing Lyotropic Liquid Crystals Based on Polyoxyethylene Phytosterols and Ionic Liquids.

    Science.gov (United States)

    Yi, Sijing; Wang, Jiao; Feng, Zhenyu; Chen, Xiao

    2017-10-05

    Soft materials of europium β-diketonate complexes constructed in lyotropic liquid crystals (LLCs) mediated by ionic liquids (ILs) are impressive for their excellent luminescence performance and stability. For the aim to further improve their mechanical processability and luminescent tunablility, the polyoxyethylene phytosterols (BPS-n) were introduced here as structure directing agents to prepare relatively "rigid" lamellar luminescent LLCs in 1-butyl-3-methyl-imidazolium hexafluorophosphate by doping europium β-diketonate complexes with different imidazolium counterions. As a result of the solvophobic sterol ring structure of BPS-n, the more effective isolation and confinement effects of europium complexes could be achieved. The longest fluorescence lifetime and the highest quantum efficiency reported so far for europium containing lyotropic organized soft materials were thus obtained. Changing the molecular structures of BPS-n with different oxyethylene chains or doped complexes with imidazolium counterions of different alkyl chain lengths, the spacings of lamellar LLC matrixes and position of dispersed complexes became tunable. The measured luminescent and rheological properties for such composite LLCs showed a dependence on the rigidity and isolation capability afforded by sterol molecules. It was also found that the increase of counterion alkyl chain length would weaken the LLC matrix's confinement and isolation effects and therefore exhibit the deteriorated luminescence performance. The enhanced luminescence efficiency and stability of doped BPS-n LLCs reflected the excellent segregation of europium complexes from each other and therefore the reduced self-quenching process. The obtained results here present the designability of LLC matrixes and their great potential to promote achieving the luminescence tunability of soft materials.

  3. Preparation and photoluminescence of some europium (III) ternary complexes with β-diketone and nitrogen heterocyclic ligands

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Dunjia, E-mail: dunjiawang@163.com; Pi, Yan; Zheng, Chunyang; Fan, Ling; Hu, Yanjun; Wei, Xianhong

    2013-10-15

    Highlights: •Preparation of europium (III) ternary complexes with β-diketone and nitrogen heterocyclic ligands. •Photoluminescence behavior of europium (III) ternary complexes. •Analysis of the Judd–Ofelt intensity parameters (Ω{sub t}), the lifetime (τ) and the luminescent quantum yield (η). -- Abstract: Preparation and photoluminescence behavior of four new europium (III) ternary complexes with β-diketones (1-(6-methoxy-naphthalen-2-yl)-3-phenyl-propane-1,3-dione (MNPPD) and 1-(4-tert-butyl-phenyl)-3-(6-methoxy-naphthalen-2-yl)-propane-1,3-dione (BPMPD)) and 2,2-dipyridine (Bipy) or 1,10-phenanthroline (Phen) were reported, in the solid state. Complexes Eu(MPPD){sub 3}·Bipy, Eu(BMPD){sub 3}·Bipy, Eu(MPPD){sub 3}·Phen and Eu(BMPD){sub 3}·Phen were characterized by elemental analysis, FT-IR, {sup 1}H NMR, UV–vis absorption. The emission spectra show narrow emission bands that arise from the {sup 5}D{sub 0} → {sup 7}F{sub J} (J = 0–4) transitions of the europium ion. Based on the emission spectra and luminescence decay curves in solid state, the intensity parameters (Ω{sub t}), lifetime (τ) and emission quantum efficiency (η) were determined. The Ω{sub 2} values indicate that the Eu(III) ion in these complexes is in a highly polarizable chemical environment. Complexes Eu(MPPD){sub 3}·Bipy and Eu(MPPD){sub 3}·Phen showed a longer lifetime (τ) and a higher luminescence quantum efficiency (η), which indicated that the energy transfer to the europium ion from MNPPD ligand is more efficient than that from BPMPD ligand.

  4. Activity composition relationships in silicate melts

    Energy Technology Data Exchange (ETDEWEB)

    Glazner, A.F.

    1990-01-01

    Equipment progress include furnace construction and electron microprobe installation. The following studies are underway: phase equilibria along basalt-rhyolite mixing line (olivine crystallization from natural silicic andensites, distribution of Fe and Mg between olivine and liquid, dist. of Ca and Na between plagioclase and liquid), enthalpy-composition relations in magmas (bulk heat capacity of alkali basalt), density model for magma ascent and contamination, thermobarometry in igneous systems (olivine/plagioclase phenocryst growth in Quat. basalt), high-pressure phase equilibria of alkali basalt, basalt-quartz mixing experiments, phase equilibria of East African basalts, and granitic minerals in mafic magma. (DLC)

  5. Determination of chlorine in silicate rocks

    Science.gov (United States)

    Peck, L.C.

    1959-01-01

    In a rapid accurate method for the determination of chlorine in silicate rocks, the rock powder is sintered with a sodium carbonate flux containing zinc oxide and magnesium carbonate. The sinter cake is leached with water, the resulting solution is filtered, and the filtrate is acidified with nitric acid. Chlorine is determined by titrating this solution with mercuric nitrate solution using sodium nitroprusside as the indicator. The titration is made in the dark with a beam of light shining through the solution. The end point of the titration is found by visually comparing the intensity of this beam of light with that of a similar beam of light in a reference solution.

  6. Microbial dissolution of silicate materials. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Schwartzman, D. [Howard Univ., Washington, DC (United States). Dept. of Biology

    1996-03-26

    The objective of this research was to better understand the role of selected thermophilic bacteria in the colonization and dissolution of silicate minerals, with potential applications to the HDR Project. The demonstration of enhanced dissolution from microbial effects is critically dependent on providing a mineral bait within a media deficient in the critical nutrient found in the mineral (e.g., Fe). Reproducible experimental conditions in batch experiments require agitation to expose mineral powders, as well as nearly similar initial conditions for both inoculated cultures and controls. It is difficult, but not impossible to ensure reproducible conditions with microbes favoring filamentous growth habits.

  7. Thermochemistry of dense hydrous magnesium silicates

    Science.gov (United States)

    Bose, Kunal; Burnley, Pamela; Navrotsky, Alexandra

    1994-01-01

    Recent experimental investigations under mantle conditions have identified a suite of dense hydrous magnesium silicate (DHMS) phases that could be conduits to transport water to at least the 660 km discontinuity via mature, relatively cold, subducting slabs. Water released from successive dehydration of these phases during subduction could be responsible for deep focus earthquakes, mantle metasomatism and a host of other physico-chemical processes central to our understanding of the earth's deep interior. In order to construct a thermodynamic data base that can delineate and predict the stability ranges for DHMS phases, reliable thermochemical and thermophysical data are required. One of the major obstacles in calorimetric studies of phases synthesized under high pressure conditions has been limitation due to the small (less than 5 mg) sample mass. Our refinement of calorimeter techniques now allow precise determination of enthalpies of solution of less than 5 mg samples of hydrous magnesium silicates. For example, high temperature solution calorimetry of natural talc (Mg(0.99) Fe(0.01)Si4O10(OH)2), periclase (MgO) and quartz (SiO2) yield enthalpies of drop solution at 1044 K to be 592.2 (2.2), 52.01 (0.12) and 45.76 (0.4) kJ/mol respectively. The corresponding enthalpy of formation from oxides at 298 K for talc is minus 5908.2 kJ/mol agreeing within 0.1 percent to literature values.

  8. Carbon Mineralization Using Phosphate and Silicate Ions

    Science.gov (United States)

    Gokturk, H.

    2013-12-01

    Carbon dioxide (CO2) reduction from combustion of fossil fuels has become an urgent concern for the society due to marked increase in weather related natural disasters and other negative consequences of global warming. CO2 is a highly stable molecule which does not readily interact with other neutral molecules. However it is more responsive to ions due to charge versus quadrupole interaction [1-2]. Ions can be created by dissolving a salt in water and then aerosolizing the solution. This approach gives CO2 molecules a chance to interact with the hydrated salt ions over the large surface area of the aerosol. Ion containing aerosols exist in nature, an example being sea spray particles generated by breaking waves. Such particles contain singly and doubly charged salt ions including Na+, Cl-, Mg++ and SO4--. Depending on the proximity of CO2 to the ion, interaction energy can be significantly higher than the thermal energy of the aerosol. For example, an interaction energy of 0.6 eV is obtained with the sulfate (SO4--) ion when CO2 is the nearest neighbor [2]. In this research interaction between CO2 and ions which carry higher charges are investigated. The molecules selected for the study are triply charged phosphate (PO4---) ions and quadruply charged silicate (SiO4----) ions. Examples of salts which contain such molecules are potassium phosphate (K3PO4) and sodium orthosilicate (Na4SiO4). The research has been carried out with first principle quantum mechanical calculations using the Density Functional Theory method with B3LYP functional and Pople type basis sets augmented with polarization and diffuse functions. Atomic models consist of the selected ions surrounded by water and CO2 molecules. Similar to the results obtained with singly and doubly charged ions [1-2], phosphate and silicate ions attract CO2 molecules. Energy of interaction between the ion and CO2 is 1.6 eV for the phosphate ion and 3.3 eV for the silicate ion. Hence one can expect that the selected

  9. Luminescent method of determination of composition of europium and terbium complexes in solution by change of intensity ratio of luminescence bands

    Energy Technology Data Exchange (ETDEWEB)

    Bel' tyukova, S.V.; Nazarenko, N.A.; Poluehktov, N.S.

    1982-03-01

    The complexes of europium and terbium with phenanthroline, ethylenediaminetetraacetate, nitrilotriacetate, some acids-phenol derivatives and ..beta..-diketones series have been used as an example to demonstrate that the value of the ratio of intensities on the two bands of europium(terbium) luminescence spectra - the one corresponding to the hypersensitive'' transition and the other, to the magnetic dipole one - can be used for determination of the complexes composition in solutions.

  10. Syntheses and electroluminescent properties of two europium ternary complexes Eu(DBM){sub 3}(PBO) and Eu(DBM){sub 3}(PBT)

    Energy Technology Data Exchange (ETDEWEB)

    Guan Min [State Key Laboratory of Rare Earth Materials Chemistry and Applications, Peking University, Beijing 100871 (China); Gao Lihua [Department of Chemistry, Beijing Normal University, Beijing 100875 (China); Wang Shanshan [State Key Laboratory of Rare Earth Materials Chemistry and Applications, Peking University, Beijing 100871 (China); Huang Chunhui [State Key Laboratory of Rare Earth Materials Chemistry and Applications, Peking University, Beijing 100871 (China)], E-mail: chhuang@pku.edu.cn; Wang Kezhi [Department of Chemistry, Beijing Normal University, Beijing 100875 (China)

    2007-12-15

    Two europium complexes, Eu(DBM){sub 3}(PBO) and Eu(DBM){sub 3}(PBT) (DBM=dibenzoylmethanato, PBO=2-(2-pyridyl)benzoxazole, PBT=2-(2-pyridyl)benzothiazole), were prepared and used as emitting materials in organic electroluminescent (EL) devices. The devices with the structures ITO/TPD/Eu(DBM){sub 3}(PBO) (or Eu(DBM){sub 3}(PBT)/BCP/Alq{sub 3}/Mg:Ag/Ag emit red light originating from the europium complexes.

  11. Petrology and Geochemistry of Calc-Silicate Schists and Calc ...

    African Journals Online (AJOL)

    Chemically the calc-silicate schists are characterized by relatively high CaO, MgO, Cr, Ni, Sr, La, Ce and Nd contents compared with the mica schist regionally associated with the marble as well as the Post-Archean Australian Shale (PAAS). Relative to the ultramafic schist the calc-silicate schists are characterized by higher ...

  12. 40 CFR 721.9513 - Modified magnesium silicate polymer (generic).

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Modified magnesium silicate polymer (generic). 721.9513 Section 721.9513 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED... Specific Chemical Substances § 721.9513 Modified magnesium silicate polymer (generic). (a) Chemical...

  13. [Adsorption characteristic and form distribution of silicate in lakes sediments].

    Science.gov (United States)

    Lü, Chang-Wei; Cui, Meng; Gao, Ji-Mei; Zhang, Xi-Yan; Wan, Li-Li; He, Jiang; Meng, Ting-Ting; Bai, Fan; Yang, Xu

    2012-01-01

    Taking surface sediments from the Wuliangsuhai Lake and Daihai Lake as adsorbent, the isothermal adsorption experiments of silicate on sediments were carried out and the adsorption behavior was explained by Langmuir, Freundlich and Temkin crossover-type equations, then the form distribution characters of silicate were studied after adsorption in this work. The results showed that the adsorption behavior of silicate on the two lakes sediments can be linear fitting in the lower concentration dose (Temkin crossover-type equations can be used to explain the adsorption behavior of silicate on the two lakes sediments, and the native adsorption silicate (NAS) and equilibrium silicate concentration (ESC(0)) calculated by the three equations could be used to explain the sink and source effects of the sediments from the two lakes; the silicate form distribution in the sediments after adsorption indicated that silicate adsorbed on particles were mainly added on the form of IEF-Si, CF-Si, IMOF-Si and OSF-Si, and the IMOF-Si and OSF-Si had important potential bioavailability.

  14. Fire Resistance of Wood Impregnated with Soluble Alkaline Silicates

    OpenAIRE

    Andrea Marisa Pereyra; Carlos Alberto Giudice

    2007-01-01

    The aim of this paper is to determine the fire performance of wood panels (Araucaria angustifolia) impregnated with soluble alkaline silicates. Commercial silicates based on sodium and potassium with 2.5/1.0 and 3.0/1.0 silica/alkali molar ratios were selected; solutions and glasses ...

  15. Natural Weathering Rates of Silicate Minerals

    Science.gov (United States)

    White, A. F.

    2003-12-01

    Silicates constitute more than 90% of the rocks exposed at Earth's land surface (Garrels and Mackenzie, 1971). Most primary minerals comprising these rocks are thermodynamically unstable at surface pressure/temperature conditions and are therefore susceptible to chemical weathering. Such weathering has long been of interest in the natural sciences. Hartt (1853) correctly attributed chemical weathering to "the efficacy of water containing carbonic acid in promoting the decomposition of igneous rocks." Antecedent to the recent interest in the role of vegetation on chemical weathering, Belt (1874) observed that the most intense weathering of rocks in tropical Nicaragua was confined to forested regions. He attributed this effect to "the percolation through rocks of rain water charged with a little acid from decomposing vegetation." Chamberlin (1899) proposed that the enhanced rates of chemical weathering associated with major mountain building episodes in Earth's history resulted in a drawdown of atmospheric CO2 that led to periods of global cooling. Many of the major characteristics of chemical weathering had been described when Merrill (1906) published the groundbreaking volume Rocks, Rock Weathering, and Soils.The major advances since that time, particularly during the last several decades, have centered on understanding the fundamental chemical, hydrologic, and biologic processes that control weathering and in establishing quantitative weathering rates. This research has been driven by the importance of chemical weathering to a number environmentally and economically important issues. Undoubtedly, the most significant aspect of chemical weathering is the breakdown of rocks to form soils, a process that makes life possible on the surface of the Earth. The availability of many soil macronutrients such as magnesium, calcium, potassium, and PO4 is directly related to the rate at which primary minerals weather. Often such nutrient balances are upset by anthropogenic

  16. Stability constants of europium complexes with a nitrogen heterocycle substituted methane-1,1-diphosphonic acid

    Energy Technology Data Exchange (ETDEWEB)

    Jensen, M.P.; Rickert, P.G.; Schmidt, M.A.; Nash, K.L.

    1996-06-01

    Even in moderately acidic solutions ([H{sup +}] > 0.01 M), N-piperidinomethane-1,1-diphosphonic acid (H{sub 4}PMDPA) is a strong complexant of trivalent lanthanide ions that shows enhanced complex solubility over previously studied 1,1-diphosphonic acids. The protonation constants of PMDPA in 2.0 M H/NaClO{sub 4} were determined by potentiometric and NMR titrations, and the stability constants for formation of complexes with Eu{sup 3+} were determined by solvent extraction. Difference in protonation equilibria induced by addition of the nitrogen heterocycle results in an increase in the complexation strength of PMDPA. In solutions containing 0.1 M H{sup +} and ligand concentrations greater than 0.02 M, PMDPA is the most effective 1,1-diphosphonic acid for europium complexation studied thus far.

  17. First principles description of the insulator-metal transition in europium monoxide

    KAUST Repository

    Wang, Hao

    2012-02-01

    Europium monoxide, EuO, is a ferromagnetic insulator. Its electronic structure under pressure and doping is investigated by means of density functional theory. We employ spin polarized electronic structure calculations including onsite electron-electron interaction for the localized Eu 4f and 5d electrons. Our results show that under pressure the ferromagnetism is stable, both for hydrostatic and uniaxial pressure, while the compound undergoes an insulator-metal transition. The insulator-metal transition in O deficient and Gd doped EuO is reproduced for an impurity concentration of 6.25%. A 10 monolayer thick EuO(1 0 0) thin film is predicted to be an insulator with a narrow band gap of 0.08 eV. © 2011 Elsevier B.V. All rights reserved.

  18. Development of europium doped BaSO4 TL OSL dual phosphor for radiation dosimetry applications

    Science.gov (United States)

    Patle, Anita; Patil, R. R.; Kulkarni, M. S.; Bhatt, B. C.; Moharil, S. V.

    2015-08-01

    This paper presents the results on the preparation and characterization of Europium-doped Barium sulfate (BaSO4: Eu) TL /OSL dual phosphor. The OSL sensitivity was found to be 11% of the commercially available Al2O3: C, using area integration method. The sample also shows good TL sensitivity and the dosimetric peak appears around 190°C with a shoulder at 282°C. After OSL readout, No change in the TL glow curve is observed. Since the observed TL peaks are not responsible for the observed OSL, good OSL as well as TL sensitivity and low fading will make this phosphor suitable for applications in radiation dosimetry using OSL as well as TL.

  19. Chemiluminescence determination of tetracyclines using Fenton system in the presence europium(III) ions

    Energy Technology Data Exchange (ETDEWEB)

    Kaczmarek, Malgorzata [Department of Rare Earths, Faculty of Chemistry, Adam Mickiewicz University, Grunwaldzka 6, 60 - 780 Poznan (Poland); Lis, Stefan, E-mail: blis@amu.edu.pl [Department of Rare Earths, Faculty of Chemistry, Adam Mickiewicz University, Grunwaldzka 6, 60 - 780 Poznan (Poland)

    2009-04-20

    A new simple chemiluminescent method for the determination of chlortetracycline (Chlor-TC), oxytetracycline (Oxy-TC) and doxycycline (Doxy-TC) is described. This method is based on the europium(III) emission as a result of the energy transfer process from the excited product of the tetracyclines oxidation to the uncomplexed Eu(III). Under the optimum conditions, calibration graphs were obtained for 4 x 10{sup -7} to 2 x 10{sup -5} mol L{sup -1} of Chlor-TC; 2 x 10{sup -7} to 2 x 10{sup -5} mol L{sup -1} of Oxy-TC and 1 x 10{sup -7} to 3 x 10{sup -5} mol L{sup -1} of Doxy-TC. The method was successfully applied to the determination of these drugs in pharmaceutical and veterinary formulation and honey.

  20. Europium-doped aluminum oxide phosphors as indicators for frontal polymerization dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Carranza, Arturo; Gewin, Mariah; Pojman, John A., E-mail: japojman@lsu.edu [Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803-1804 (United States)

    2014-06-15

    In this study, we present an inexpensive and practical method that allows the monitoring and visualization of front polymerization, propagation, and dynamics. Commercially available europium-doped aluminum oxide powders were combined with video imaging to visualize free-radical propagating polymer fronts. In order to demonstrate the applicability of this method, frontal copolymerization reactions of propoxylated glycerin triacrylate (EB53), pentaerythritol triacrylate (PETA), and pentaerythritol tetra-acrylate (PETEA) with 1,1-Bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane (Luperox 231®) as an initiator were studied and compared to the results obtained by IR imaging. Systems exhibiting higher filler loading, higher EB53 content, and less acrylated monomers showed a marked decrease in front velocity, while those with more acrylated monomers and higher crosslinking density showed a marked increase in front velocity. Finally, in order to show the potential of the imaging technique, we studied fronts propagating in planar and spherical geometries.

  1. Europium-doped aluminum oxide phosphors as indicators for frontal polymerization dynamics.

    Science.gov (United States)

    Carranza, Arturo; Gewin, Mariah; Pojman, John A

    2014-06-01

    In this study, we present an inexpensive and practical method that allows the monitoring and visualization of front polymerization, propagation, and dynamics. Commercially available europium-doped aluminum oxide powders were combined with video imaging to visualize free-radical propagating polymer fronts. In order to demonstrate the applicability of this method, frontal copolymerization reactions of propoxylated glycerin triacrylate (EB53), pentaerythritol triacrylate (PETA), and pentaerythritol tetra-acrylate (PETEA) with 1,1-Bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane (Luperox 231®) as an initiator were studied and compared to the results obtained by IR imaging. Systems exhibiting higher filler loading, higher EB53 content, and less acrylated monomers showed a marked decrease in front velocity, while those with more acrylated monomers and higher crosslinking density showed a marked increase in front velocity. Finally, in order to show the potential of the imaging technique, we studied fronts propagating in planar and spherical geometries.

  2. Electrochemiluminescence Study of Europium (III Complex with Coumarin3-Carboxylic Acid

    Directory of Open Access Journals (Sweden)

    Stefan Lis

    2008-01-01

    Full Text Available The europium (III complex of coumarin-3-carboxylic acid (C3CA has been prepared and characterized on the basis of elemental analysis, IR, and emission (photoluminescence and electrochemiluminescence spectroscopy. The synthesised complex having a formula Eu(C3CA2(NO3(H2O2 was photophysically characterized in solution and in the solid state. Electrochemiluminescence, ECL, of the system containing the Eu(III/C3CA complex was studied using an oxide-covered aluminium electrode. The goal of these studies was to show the possibility of the use of electrochemical excitation of the Eu(III ion in aqueous solution for emission generation. The generated ECL emission was very weak, and therefore its measurements and spectral analysis were carried out with the use of cut-off filters method. The studies proved a predominate role of the ligand-to-metal energy transfer (LMET in the generated ECL.

  3. Europium incorporated in silica matrix obtained by sol-gel: luminescent materials

    Directory of Open Access Journals (Sweden)

    Nassar Eduardo José

    2003-01-01

    Full Text Available In this work we report some aspects of the chemistry involved in the preparation of modified silicon oxide by the sol-gel process. Europium III compounds were used as luminescent probe. An organic-inorganic hybrid was obtained by hydrolysis of tetraethylorthosilicate (TEOS and 3-aminopropyltriethoxysilane (APTS. The Eu III compounds were added in different ways. In the first, silica was prepared in the presence of Eu III, and in the second, Eu III was added on the silica surface. These materials were studied by luminescence, infrared spectroscopy and termogravimetric analysis. The results obtained for the hybrid material show different behavior for Eu III emission, which could be excited by the antenna effect and the influence of the surrounding in the luminescence quenching. The thermogravimetric data present different mass loss in samples to range temperature 50 - 150 °C. Thermogravimetric and infrared spectra showed that inorganic polymers incorporated the organic part.

  4. Europium as an inhibitor of Amyloid-β(1-42) induced membrane permeation.

    Science.gov (United States)

    Williams, Thomas L; Urbanc, Brigita; Marshall, Karen E; Vadukul, Devkee M; Jenkins, A Toby A; Serpell, Louise C

    2015-10-24

    Soluble Amyloid-beta (Aβ) oligomers are a source of cytotoxicity in Alzheimer's disease (AD). The toxicity of Aβ oligomers may arise from their ability to interact with and disrupt cellular membranes mediated by GM1 ganglioside receptors within these membranes. Therefore, inhibition of Aβ-membrane interactions could provide a means of preventing the toxicity associated with Aβ. Here, using Surface Plasmon field-enhanced Fluorescence Spectroscopy, we determine that the lanthanide, Europium III chloride (Eu(3+)), strongly binds to GM1 ganglioside-containing membranes and prevents the interaction with Aβ42 leading to a loss of the peptides ability to cause membrane permeation. Here we discuss the molecular mechanism by which Eu(3+) inhibits Aβ42-membrane interactions and this may lead to protection of membrane integrity against Aβ42 induced toxicity. Copyright © 2015 The Authors. Published by Elsevier B.V. All rights reserved.

  5. Radiation effects on beta /10.6/ of pure and europium doped KCl

    Science.gov (United States)

    Grimes, H. H.; Maisel, J. E.; Hartford, R. H.

    1975-01-01

    Changes in the optical absorption coefficient as the result of X-ray and electron bombardment of pure monocrystalline and polycrystalline KCl and of divalent europium doped polycrystalline KCl were determined. A constant heat flow calorimetric method was used to measure the optical absorption coefficients. Both 300 kV X-ray irradiation and 2 MeV electron irradiation produced increases in the optical absorption coefficient at room temperature. X-ray irradiation produced more significant changes in pure monocrystalline KCl than equivalent amounts of electron irradiation. Electron irradiation of pure and Eu-doped polycrystalline KCl produced increases in the absorption by as much as a factor of 20 over untreated material. Bleaching of the electron-irradiated doped KCl with 649 millimicron light produced a further increase.

  6. Excitation functions for the formation of longer lived isotopes by deuteron irradiation of Europium

    Energy Technology Data Exchange (ETDEWEB)

    Takács, S., E-mail: stakacs@atomki.hu [Institute for Nuclear Research, Hungarian Academy of Sciences, 4026 Debrecen (Hungary); Tárkányi, F. [Institute for Nuclear Research, Hungarian Academy of Sciences, 4026 Debrecen (Hungary); Hermanne, A.; Adam-Rebeles, R. [Cyclotron Laboratory, Vrije Universiteit Brussel, Brussels 1090 (Belgium); Takács, M.P. [Institute for Nuclear Research, Hungarian Academy of Sciences, 4026 Debrecen (Hungary); Institute of Physics, University of Debrecen, 4026 Debrecen (Hungary)

    2013-09-01

    Excitation functions for nuclear reactions induced on natural europium targets by energetic deuterons were studied up to 50 MeV. A standard stacked foil technique was used for irradiation and high resolution gamma spectrometry was applied for activity assessment. Direct or cumulative cross sections for reaction products with half-life longer than 2 h were determined. Reactions leading to the formation of the radionuclides {sup 147,149,151,153}Gd, {sup 147,148,149,150m,150g,152m,152g,154g}Eu, {sup 153}Sm and {sup 150}Pm were studied. In most cases no earlier data were available in the literature. The new experimental results were compared with values tabulated in the on-line TENDL2011 library.

  7. Quadrupole splitting and Eu partial lattice dynamics in europium orthophosphate EuPO {sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Klobes, B., E-mail: b.klobes@fz-juelich.de [JARA-FIT - Forschungszentrum Jülich GmbH, Jülich Centre for Neutron Science JCNS and Peter Grünberg Institute PGI (Germany); Arinicheva, Y., E-mail: y.arinicheva@fz-juelich.de; Neumeier, S., E-mail: s.neumeier@fz-juelich.de [Forschungszentrum Jülich GmbH, Institute of Energy and Climate Research (IEK-6) Nuclear Waste Management and Reactor Safety (Germany); Simon, R. E., E-mail: r.simon@fz-juelich.de; Jafari, A., E-mail: a.jafari@fz-juelich.de [JARA-FIT - Forschungszentrum Jülich GmbH, Jülich Centre for Neutron Science JCNS and Peter Grünberg Institute PGI (Germany); Bosbach, D., E-mail: d.bosbach@fz-juelich.de [Forschungszentrum Jülich GmbH, Institute of Energy and Climate Research (IEK-6) Nuclear Waste Management and Reactor Safety (Germany); Hermann, R. P., E-mail: hermannrp@ornl.gov [JARA-FIT - Forschungszentrum Jülich GmbH, Jülich Centre for Neutron Science JCNS and Peter Grünberg Institute PGI (Germany)

    2016-12-15

    Hyperfine interactions in europium orthophosphate EuPO{sub 4} were investigated using {sup 151}Eu Mössbauer spectroscopy from 6 to 300 K. The value of the quadrupole splitting and the asymmetry parameter were refined and further substantiated by nuclear forward scattering data obtained at room temperature. The temperature dependence of the relative absorption was modeled with an Eu specific Debye temperature of 221(1) K. Eu partial lattice dynamics were probed by means of nuclear inelastic scattering and the mean force constant, the Lamb-Mössbauer factor, the internal energy, the vibrational entropy, the average phonon group velocity were calculated using the extracted density of phonon states. In general, Eu specific vibrations are characterized by rather small phonon energies and contribute strongly to the total entropy of the system. Although there is no classical Debye like behavior at low vibrational energies, the average phonon group velocity can be reasonably approximated using a linear fit.

  8. Photoluminescent polymer electrolyte based on agar and containing europium picrate for electrochemical devices

    Energy Technology Data Exchange (ETDEWEB)

    Lima, E. [Centro de Quimica, Universidade do Minho, Gualtar, 4710-057 Braga (Portugal); Raphael, E.; Sentanin, F. [IQSC, Universidade de Sao Paulo, 13566-590 Sao Carlos, SP (Brazil); Rodrigues, L.C. [Centro de Quimica, Universidade do Minho, Gualtar, 4710-057 Braga (Portugal); Ferreira, R.A.S.; Carlos, L.D. [Departamento de Fisica, CICECO, Universidade de Aveiro, 3810-193 Aveiro (Portugal); Silva, M.M., E-mail: nini@quimica.uminho.pt [Centro de Quimica, Universidade do Minho, Gualtar, 4710-057 Braga (Portugal); Pawlicka, A. [IQSC, Universidade de Sao Paulo, 13566-590 Sao Carlos, SP (Brazil)

    2012-04-15

    Highlights: Black-Right-Pointing-Pointer We prepared ionic conducting membranes for the specific requirements of the device. Black-Right-Pointing-Pointer Luminescent reporter groups, with many applications in biotechnology. Black-Right-Pointing-Pointer Thermal and electrochemical stability of electrolytes is adequate for application. - Abstract: Dispersion of photoluminescent rare earth metal complexes in polymer matrices is of great interest due to the possibility of avoiding the saturation of the photoluminescent signal. The possibility of using a natural ionic conducting polymer matrix was investigated in this study. Samples of agar-based electrolytes containing europium picrate were prepared and characterized by physical and chemical analyses. The FTIR spectra indicated strong interaction of agar O-H and 3,6-anhydro-galactose C-O groups with glycerol and europium picrate. The DSC analyses revealed no glass transition temperature of the samples in the -60 to 250 Degree-Sign C range. From the thermogravimetry (TG), a thermal stability of the samples of up to 180 Degree-Sign C was stated. The membranes were subjected to ionic conductivity measurement, which provided the values of 2.6 Multiplication-Sign 10{sup -6} S/cm for the samples with acetic acid and 1.6 Multiplication-Sign 10{sup -5} S/cm for the samples without acetic acid. Moreover, the temperature-dependent ionic conductivity measurements revealed both Arrhenius and VTF models of the conductivity depending on the sample. Surface visualization through scanning electron microscopy (SEM) demonstrated good uniformity. The samples were also applied in small electrochromic devices and showed good electrochemical stability. The present work confirmed that these materials may perform as satisfactory multifunctional component layers in the field of electrochemical devices.

  9. Spectroscopic investigation on europium doped heavy metal borate glasses for red luminescent application

    Energy Technology Data Exchange (ETDEWEB)

    Hegde, Vinod; Wagh, Akshatha; Kamath, Sudha D. [Manipal University, Department of Physics, Manipal Institute of Technology, Manipal (India); Hegde, Hemanth [Manipal University, Department of Chemistry, Manipal Institute of Technology, Manipal (India); Vishwanath, C.S.D. [Sri Venkateswara University, Department of Physics, Tirupati (India)

    2017-05-15

    The present study explores a new borate family glasses based on 10ZnO-5Na{sub 2}O-10Bi{sub 2}O{sub 3}-(75 - x) B{sub 2}O{sub 3}-xEu{sub 2}O{sub 3} (x = 0, 0.1, 0.5, 1, 1.5, 2, 3 mol%) composition, synthesized by rapid melt quench technique. Prepared glasses were subjected to the density and refractive index measurements and their values were used to calculate other physical properties of the glass matrix as a function of Eu{sup 3+} concentration. XRD confirmed amorphous nature of the glasses. FTIR spectra in the absorption mode were recorded in the 400-4000 cm{sup -1} region to identify different functional groups in the glass matrix. Deconvoluted FTIR spectra showed increase in BO{sub 4} units with rise in europium content which confirmed the 'network strengthener' role of europium ions by creating bridging oxygens (BOs). Optical properties were investigated for their luminescence behavior through various spectroscopic techniques such as UV-Vis-NIR absorption, excitation, emission, decay profiles, and color measurements at room temperature. Lasing properties of the glasses like total radiative life time, branching ratio, emission cross section, and optical gain were obtained from the calculated Judd-Ofelt (Ω{sub 2},Ω{sub 4}) intensity parameters. From the measured values of emission, cross sections, branching ratios, life times, strong photoluminescence features, and CIE chromaticity coordinates, 0.5 mol% of Eu{sup 3+} ions doped ZnNaBiB glasses showed optimum performance and are potential candidate for red light generation at 613 nm. (orig.)

  10. Europium nanoparticle-based high performing immunoassay for the screening of treponemal antibodies.

    Directory of Open Access Journals (Sweden)

    Sheikh M Talha

    Full Text Available Treponema pallidum subspecies pallidum (Tp is the causative agent of syphilis which mainly spreads through sexual contact, blood transfusion and perinatal route. In order to curtail the spread of the infection and to clinically manage the disease, timely, accurate and reliable diagnosis is very important. We have developed an immunoassay for the detection of treponemal antibodies in human serum or plasma samples. In vivo biotinylated and non-biotinylated versions of the recombinant antigen were designed by the fusion of three Tp-specific antigens namely Tp15, Tp17 and Tp47. These fusion antigens were expressed in E. coli and purified using single-step metal affinity chromatography. Biotinylated fusion antigen immobilized on streptavidin coated plate was used to capture the treponemal antibodies and the non-biotinylated antigen coated on europium nanoparticles was used as tracer. Assays with two different incubation times of 10 min and 1 h were developed, and following the incubation the europium fluorescence was measured using time-resolved fluorometry. The developed time-resolved fluorometric (TRF immunoassays were evaluated with in-house and commercial serum/plasma sample panels. For well-established treponemal antibodies positive or negative samples, the sensitivity of TRF immunoassay with 10 min incubation time was 97.4%, and of TRF immunoassay with 1 h incubation time was 98.7%, and the specificities of both the TRF immunoassays were 99.2%. For the samples with discordant results with the reference assays, both the TRF immunoassays showed better specificity than the Enzygnost syphilis enzyme immunoassay as a screening test. The two different incubation times did not have any significant effect on the signal to cutoff (S/Co ratios obtained with the two immunoassays (p=0.06. Our results indicate that the developed immunoassay with a short incubation time of 10 min has the potential to be used in clinical laboratories and in blood

  11. Visible-light-excited and europium-emissive nanoparticles for highly-luminescent bioimaging in vivo.

    Science.gov (United States)

    Wu, Yongquan; Shi, Mei; Zhao, Lingzhi; Feng, Wei; Li, Fuyou; Huang, Chunhui

    2014-07-01

    Europium(III)-based material showing special milliseconds photoluminescence lifetime has been considered as an ideal time-gated luminescence probe for bioimaging, but is still limited in application in luminescent small-animal bioimaging in vivo. Here, a water-soluble, stable, highly-luminescent nanosystem, Ir-Eu-MSN (MSN = mesoporous silica nanoparticles, Ir-Eu = [Ir(dfppy)2(pic-OH)]3Eu·2H2O, dfppy = 2-(2,4-difluorophenyl)pyridine, pic-OH = 3-hydroxy-2-carboxypyridine), was developed by an in situ coordination reaction to form an insoluble dinuclear iridium(III) complex-sensitized-europium(III) emissive complex within mesoporous silica nanoparticles (MSNs) which had high loading efficiency. Compared with the usual approach of physical adsorption, this in-situ reaction strategy provided 20-fold the loading efficiency (43.2%) of the insoluble Ir-Eu complex in MSNs. These nanoparticles in solid state showed bright red luminescence with high quantum yield of 55.2%, and the excitation window extended up to 470 nm. These Ir-Eu-MSN nanoparticles were used for luminescence imaging in living cells under excitation at 458 nm with confocal microscopy, which was confirmed by flow cytometry. Furthermore, the Ir-Eu-MSN nanoparticles were successfully applied into high-contrast luminescent lymphatic imaging in vivo under low power density excitation of 5 mW cm(-2). This synthetic method provides a universal strategy of combining hydrophobic complexes with hydrophilic MSNs for in vivo bioimaging. Copyright © 2014 Elsevier Ltd. All rights reserved.

  12. Europium Nanoparticle-Based High Performing Immunoassay for the Screening of Treponemal Antibodies

    Science.gov (United States)

    Talha, Sheikh M.; Hytönen, Jukka; Westhorpe, Adam; Kumar, Sushil; Khanna, Navin; Pettersson, Kim

    2013-01-01

    Treponema pallidum subspecies pallidum (Tp) is the causative agent of syphilis which mainly spreads through sexual contact, blood transfusion and perinatal route. In order to curtail the spread of the infection and to clinically manage the disease, timely, accurate and reliable diagnosis is very important. We have developed an immunoassay for the detection of treponemal antibodies in human serum or plasma samples. In vivo biotinylated and non-biotinylated versions of the recombinant antigen were designed by the fusion of three Tp-specific antigens namely Tp15, Tp17 and Tp47. These fusion antigens were expressed in E. coli and purified using single-step metal affinity chromatography. Biotinylated fusion antigen immobilized on streptavidin coated plate was used to capture the treponemal antibodies and the non-biotinylated antigen coated on europium nanoparticles was used as tracer. Assays with two different incubation times of 10 min and 1 h were developed, and following the incubation the europium fluorescence was measured using time-resolved fluorometry. The developed time-resolved fluorometric (TRF) immunoassays were evaluated with in-house and commercial serum/plasma sample panels. For well-established treponemal antibodies positive or negative samples, the sensitivity of TRF immunoassay with 10 min incubation time was 97.4%, and of TRF immunoassay with 1 h incubation time was 98.7%, and the specificities of both the TRF immunoassays were 99.2%. For the samples with discordant results with the reference assays, both the TRF immunoassays showed better specificity than the Enzygnost syphilis enzyme immunoassay as a screening test. The two different incubation times did not have any significant effect on the signal to cutoff (S/Co) ratios obtained with the two immunoassays (p = 0.06). Our results indicate that the developed immunoassay with a short incubation time of 10 min has the potential to be used in clinical laboratories and in blood-bank settings as a

  13. Semiconducting polymer encapsulated mesoporous silica particles with conjugated Europium complexes: toward enhanced luminescence under aqueous conditions.

    Science.gov (United States)

    Zhang, Jixi; Prabhakar, Neeraj; Näreoja, Tuomas; Rosenholm, Jessica M

    2014-01-01

    Immobilization of lanthanide organic complexes in meso-organized hybrid materials for luminescence applications have attracted immense interest due to the possibility of controlled segregation at the nanoscopic level for novel optical properties. Aimed at enhancing the luminescence intensity and stability of the hybrid materials in aqueous media, we developed polyvinylpyrrolidone (PVP) stabilized, semiconducting polymer (poly(9-vinylcarbazole), PVK) encapsulated mesoporous silica hybrid particles grafted with Europium(III) complexes. Monosilylated β-diketonate ligands (1-(2-naphthoyl)-3,3,3-trifluoroacetonate, NTA) were first co-condensed in the mesoporous silica particles as pendent groups for bridging and anchoring the lanthanide complexes, resulting in particles with an mean diameter of ∼ 450 nm and a bimodal pore size distribution centered at 3.5 and 5.3 nm. PVK was encapsulated on the resulted particles by a solvent-induced surface precipitation process, in order to seal the mesopores and protect Europium ions from luminescence quenching by producing a hydrophobic environment. The obtained polymer encapsulated MSN-EuLC@PVK-PVP particles exhibit significantly higher intrinsic quantum yield (Φ(Ln) = 39%) and longer lifetime (τ(obs) = 0.51 ms), as compared with those without polymer encapsulation. Most importantly, a high luminescence stability was realized when MSN-EuLC@PVK-PVP particles were dispersed in various aqueous media, showing no noticeable quenching effect. The beneficial features and positive attributes of both mesoporous silica and semiconducting polymers as lanthanide-complex host were merged in a single hybrid carrier, opening up the possibility of using these hybrid luminescent materials under complex aqueous conditions such as biological/physiological environments.

  14. Surface-imprinted nanofilaments for europium-amplified luminescent detection of fluoroquinolone antibiotics.

    Science.gov (United States)

    Zdunek, Jolanta; Benito-Peña, Elena; Linares, Ana; Falcimaigne-Cordin, Aude; Orellana, Guillermo; Haupt, Karsten; Moreno-Bondi, María C

    2013-07-29

    The development and characterization of novel, molecularly imprinted polymer nanofilament-based optical sensors for the analysis of enrofloxacin, an antibiotic widely used for human and veterinary applications, is reported. The polymers were prepared by nanomolding in porous alumina by using enrofloxacin as the template. The antibiotic was covalently immobilized on to the pore walls of the alumina by using different spacers, and the prepolymerization mixture was cast in the pores and the polymer synthesized anchored onto a glass support through UV polymerization. Various parameters affecting polymer selectivity were evaluated to achieve optimal recognition, namely, the spacer arm length and the binding solvent. The results of morphological characterization, binding kinetics, and selectivity of the optimized polymer material for ENR and its derivatives are reported. For sensing purposes, the nanofilaments were incubated in solutions of the target molecule in acetonitrile/HEPES buffer (100 mM, pH 7.5, 50:50, v/v) for 20 min followed by incubation in a 10 mM solution of europium(III) ions to generate a europium(III)-enrofloxacin complex on the polymer surface. The detection event was based on the luminescence of the rare-earth ion (λexc=340 nm; λem=612 nm) that results from energy transfer from the antibiotic excited state to the metal-ion emitting excited state. The limit of detection of the enrofloxacin antibiotic was found to be 0.58 μM. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Faster Synthesis of Beta-Diketonate Ternary Europium Complexes: Elapsed Times & Reaction Yields.

    Science.gov (United States)

    Lima, Nathalia B D; Silva, Anderson I S; Gerson, P C; Gonçalves, Simone M C; Simas, Alfredo M

    2015-01-01

    β-diketonates are customary bidentate ligands in highly luminescent ternary europium complexes, such as Eu(β-diketonate)3(L)2, where L stands for a nonionic ligand. Usually, the syntheses of these complexes start by adding, to an europium salt such as EuCl3(H2O)6, three equivalents of β-diketonate ligands to form the complexes Eu(β-diketonate)3(H2O)2. The nonionic ligands are subsequently added to form the target complexes Eu(β-diketonate)3(L)2. However, the Eu(β-diketonate)3(H2O)2 intermediates are frequently both difficult and slow to purify by recrystallization, a step which usually takes a long time, varying from days to several weeks, depending on the chosen β-diketonate. In this article, we advance a novel synthetic technique which does not use Eu(β-diketonate)3(H2O)2 as an intermediate. Instead, we start by adding 4 equivalents of a monodentate nonionic ligand L straight to EuCl3(H2O)6 to form a new intermediate: EuCl3(L)4(H2O)n, with n being either 3 or 4. The advantage is that these intermediates can now be easily, quickly, and efficiently purified. The β-diketonates are then carefully added to this intermediate to form the target complexes Eu(β-diketonate)3(L)2. For the cases studied, the 20-day average elapsed time reduced to 10 days for the faster synthesis, together with an improvement in the overall yield from 42% to 69%.

  16. Modified magnetic and optical properties of manganese nanoparticles incorporated europium doped magnesium borotellurite glass

    Energy Technology Data Exchange (ETDEWEB)

    Aziz, Siti Maisarah; Sahar, M.R., E-mail: mrahim057@gmail.com; Ghoshal, S.K.

    2017-02-01

    This paper reports the modified optical and magnetic properties of europium (Eu{sup 3+}) ions doped and Manganese nanoparticles (NPs) embedded Magnesium Borotellurite glass synthesized via melt quenching method. The influence of varying Mn NPs concentrations on the magnetic, absorption and emission properties of such glass samples are determined. Stables, transparent and amorphous glasses are obtained. The observed modification of the electronic polarizability is interpreted in terms of the generation of non-bridging oxygen (NBO) and bridging oxygen (BO) in the amorphous network. TEM images manifested the growth of Mn NPs with average diameter 11±1 nm. High-resolution TEM reveals that the lattice spacing of manganese nanoparticles is 0.308 nm at (112) plane. The emission spectra revealed four prominent peaks centered at 587 nm, 610 nm, 651 nm and 700 nm assigned to the transition from {sup 5}D{sub 0} →{sup 7}F{sub J} (J=1, 2, 3, 4) states of Eu{sup 3+} ion. A significant drop in the luminescence intensity due to the incorporation of Mn NPs is ascribed to the enhanced energy transfer from the Eu{sup 3+} ion to NPs. Prepared glass systems exhibited paramagnetic behavior. - Highlights: • The europium doped magnesium borotellurite glasses embedded Mn NPs prepared using the conventional melt-quenching method. • The TEM result reveals the size of Mn NPs while its planar spacing has been determined by HRTEM. • The luminescence properties of TeO{sub 2}–B{sub 2}O{sub 3}–MgO–Eu{sub 2}O{sub 3}–Mn{sub 3}O{sub 4} glasses have been investigated as effect of Mn NPs content. • The magnetization measurement of glass sample is carried out using vibrating sample magnetometer (VSM)

  17. Red polymer light-emitting devices based on an oxadiazole-functionalized europium(III) complex

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yu, E-mail: liuyu03b@126.com [Department of Chemistry, Key Lab of Environment-Friendly Chemistry and Application in the Ministry of Education, Xiangtan University, Xiangtan 411105 (China); Wang, Yafei [Department of Chemistry, Key Lab of Environment-Friendly Chemistry and Application in the Ministry of Education, Xiangtan University, Xiangtan 411105 (China); Li, Chun [Institute of Polymer Optoelectronic Materials and Devices, South China University of Technology, Guangzhou 510640 (China); Huang, Ying; Dang, Dongfeng; Zhu, Meixiang [Department of Chemistry, Key Lab of Environment-Friendly Chemistry and Application in the Ministry of Education, Xiangtan University, Xiangtan 411105 (China); Zhu, Weiguo, E-mail: zhuwg18@126.com [Department of Chemistry, Key Lab of Environment-Friendly Chemistry and Application in the Ministry of Education, Xiangtan University, Xiangtan 411105 (China); Cao, Yong, E-mail: yongcao@scut.edu.cn [Institute of Polymer Optoelectronic Materials and Devices, South China University of Technology, Guangzhou 510640 (China)

    2014-02-14

    A novel tris(dibenzoylmethanato)[5-(2-(4-tert-butylbenzenyl)-5-benzenyl-1,3, 4-oxadiazole-4′)-1,10-phenanthroline]europium(III) [Eu(DBM){sub 3}(BuOXD-Phen)] containing an electron-transporting oxadiazole-functionalized phenanthroline ligand was synthesized and characterized. Its UV–vis absorption and photoluminescence (PL), as well as the electroluminescence (EL) in polymer light-emitting devices (PLEDs) were investigated. The double-layer PLEDs with a configuration of ITO/PEDOT:PSS (50 nm)/PVK (40 nm)/PFO:PBD (30%):Eu(DBM){sub 3}(BuOXD-Phen) (1–8 wt %) (80 nm)/Ba (4 nm)/Al (150 nm) were fabricated. Saturated red Eu{sup 3+} ion emission, based on the {sup 5}D{sub 0} → {sup 7}F{sub 2} transition, is centered at a wavelength of 614 nm with a full width at half maximum (FWHM) of 10 nm. The highest external quantum efficiency (QE{sub ext}) of 1.26% at current density of 1.65 mA cm{sup −2}, with a maximum brightness of 568 cd m{sup −2} at 137.8 mA cm{sup −2} was achieved from the device at 1 wt % dopant concentration. - Highlights: • An oxadiazole-functionalized europium(III) complex of Eu(DBM){sub 3}(BuOXD-Phen) was presented. • The optophysical properties of Eu(DBM){sub 3}(BuOXD-Phen) were investigated. • Saturated red emission was observed in the PLEDs. • An external quantum efficiency of 1.26% was obtained in these devices.

  18. Kinetics of iron oxidation in silicate melts

    Energy Technology Data Exchange (ETDEWEB)

    Magnien, V.; Neuville, D.R.; Cormier, L.; Mysen, B.O.; Pinet, O.; Richet, P

    2004-07-01

    High-temperature XANES experiments at the Fe K-edge have been used to study the kinetics of iron oxidation in a supercooled melt of Fe-bearing pyroxene composition. These experiments, made just above the glass transition between 600 and 700 deg C, show that variations in relative abundances of ferric and ferrous iron can be determined in situ at such temperatures. The kinetics of iron oxidation do not vary much with temperature down to the glass transition. This suggests that rate-limiting factor in this process is not oxygen diffusion, which is coupled to relaxation of the silicate network, but diffusion of network modifying cations along with a counter flux of electrons. To give a firmer basis to redox determinations made from XANES spectroscopy, the redox state of a series of a samples was first determined from wet chemical, Moessbauer spectroscopy and electron microprobe analyses. (authors)

  19. Selective silicate-directed motility in diatoms

    DEFF Research Database (Denmark)

    Bondoc, Karen Grace V.; Heuschele, Jan; Gillard, Jeroen

    2016-01-01

    Diatoms are highly abundant unicellular algae that often dominate pelagic as well as benthic primary production in the oceans and inland waters. Being strictly dependent on silica to build their biomineralized cell walls, marine diatoms precipitate 240 × 10(12) mol Si per year, which makes them...... the major sink in the global Si cycle. Dissolved silicic acid (dSi) availability frequently limits diatom productivity and influences species composition of communities. We show that benthic diatoms selectively perceive and behaviourally react to gradients of dSi. Cell speed increases under d......Si-limited conditions in a chemokinetic response and, if gradients of this resource are present, increased directionality of cell movement promotes chemotaxis. The ability to exploit local and short-lived dSi hotspots using a specific search behaviour likely contributes to micro-scale patch dynamics in biofilm...

  20. Thermal Ablation Modeling for Silicate Materials

    Science.gov (United States)

    Chen, Yih-Kanq

    2016-01-01

    A general thermal ablation model for silicates is proposed. The model includes the mass losses through the balance between evaporation and condensation, and through the moving molten layer driven by surface shear force and pressure gradient. This model can be applied in the ablation simulation of the meteoroid and the glassy ablator for spacecraft Thermal Protection Systems. Time-dependent axisymmetric computations are performed by coupling the fluid dynamics code, Data-Parallel Line Relaxation program, with the material response code, Two-dimensional Implicit Thermal Ablation simulation program, to predict the mass lost rates and shape change. The predicted mass loss rates will be compared with available data for model validation, and parametric studies will also be performed for meteoroid earth entry conditions.

  1. Lithium alumino-silicate ion source development

    Science.gov (United States)

    Roy, Prabir Kumar; Seidl, Peter A.; Kwan, Joe W.; Greenway, Wayne G.; Waldron, William L.; Wu, James K.; Mazaheri, Kavous

    2009-11-01

    We report experimental progress on Li+ source development in preparation for warm dense matter heating experiments. To uniformly heat targets to electron-volt temperatures for the study of warm dense matter, we are pursuing the use of a low (E spodumene and β-eucryptite, each of area 0.31 cm2, have been fabricated for ion emission measurements. These surface ionization sources are heated to 1200 to 1300 C where they preferentially emit singly ionized alkali ions. Tight process controls were necessary in preparing and sintering the alumino-silicate to the porous tungsten substrate to produce an emitter that gives uniform ion emission, sufficient current density and low beam emittance. Current density limit of the two kinds have been measured, and ion species identification of possible contaminants has been verified with a Wien (E x B) filter.

  2. Electron paramagnetic resonance and photoluminescence investigation of europium local structure in oxyfluoride glass ceramics containing SrF2 nanocrystals

    Science.gov (United States)

    Antuzevics, A.; Kemere, M.; Krieke, G.; Ignatans, R.

    2017-10-01

    Different compositions of europium doped aluminosilicate oxyfluoride glass ceramics prepared in air atmosphere have been studied by electron paramagnetic resonance (EPR) and optical spectroscopy methods. X-ray diffraction (XRD) and transmission electron microscopy (TEM) measurements show presence of homogenously distributed SrF2 nanocrystals after the heat treatment of the precursor glass. Efficient Eu3+ incorporation in the high symmetry environment of glass ceramics is observed from the photoluminescence spectra. EPR spectra indicate Eu3+ → Eu2+ reduction upon precipitation of crystalline phases in the glass matrix. For composition abundant with Eu2+ in the glassy state such behaviour is not detected. Local structure around europium ions is discussed based on differences in chemical compositions.

  3. Bright, highly water-soluble triazacyclononane europium complexes to detect ligand binding with time-resolved FRET microscopy.

    Science.gov (United States)

    Delbianco, Martina; Sadovnikova, Victoria; Bourrier, Emmanuel; Mathis, Gérard; Lamarque, Laurent; Zwier, Jurriaan M; Parker, David

    2014-09-26

    Luminescent europium complexes are used in a broad range of applications as a result of their particular emissive properties. The synthesis and application of bright, highly water-soluble, and negatively charged sulfonic- or carboxylic acid derivatives of para-substituted aryl-alkynyl triazacyclononane complexes are described. Introduction of the charged solubilizing moieties suppresses cellular uptake or adsorption to living cells making them applicable for labeling and performing assays on membrane receptors. These europium complexes are applied to monitor fluorescent ligand binding on cell-surface proteins with time-resolved Förster resonance energy transfer (TR-FRET) assays in plate-based format and using TR-FRET microscopy. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Optical and spectral studies on pure and europium doped olgite type Na(Sr,Ba)PO4 ceramics.

    Science.gov (United States)

    Jawaher, K Rackesh; Jagannathan, R; Das, S Jerome; Krishnan, S

    2015-04-05

    Europium ion doped olgite type Na(Sr,Ba)PO4 ceramics, a new generation of light emitting bulb, was prepared by a high temperature solid-state reaction method. The synthesized materials were subjected to various characterizations such as X-ray powder diffraction, Scanning electron microscopy and FT-IR spectra measurements. The EPR spectrum of the sample exhibits a well-resolved hyperfine structure of 151Eu2+ and 153Eu2+ isotopes and the g value has been calculated. Fluorescence spectra revealed that europium ions were present in divalent as well as in the trivalent oxidation states. The critical distance for energy transfer between Eu2+ and Eu2+ ion is calculated as 20Å, which is in good agreement with that of experimental data. The FTIR analysis reveals all the vibrations of PO4(3-) ions. Copyright © 2015 Elsevier B.V. All rights reserved.

  5. A highly sensitive europium nanoparticle-based immunoassay for detection of influenza A/B virus antigen in clinical specimens.

    Science.gov (United States)

    Zhang, Panhe; Vemula, Sai Vikram; Zhao, Jiangqin; Du, Bingchen; Mohan, Haleyurgirisetty; Liu, Jikun; El Mubarak, Haja Sittana; Landry, Marie L; Hewlett, Indira

    2014-12-01

    We report the development of a novel europium nanoparticle-based immunoassay (ENIA) for rapid detection of influenza A and influenza B viruses. The ENIA demonstrated sensitivities of 90.7% (147/162) for influenza A viruses and 81.80% (9/11) for influenza B viruses compared to those for an in-house reverse transcription (RT)-PCR assay in testing of influenza-positive clinical samples. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

  6. Semiconducting polymer dots doped with europium complexes showing ultranarrow emission and long luminescence lifetime for time-gated cellular imaging.

    Science.gov (United States)

    Sun, Wei; Yu, Jiangbo; Deng, Ruiping; Rong, Yu; Fujimoto, Bryant; Wu, Changfeng; Zhang, Hongjie; Chiu, Daniel T

    2013-10-18

    Bright dots: Semiconducting polymer dots (Pdots) doped with europium complexes possess line-like fluorescence emission, high quantum yield, and long fluorescence lifetime. The Pdots successfully labeled receptors on cells. The long fluorescence lifetime of the Pdots was used to distinguish them from other red fluorescence emitting nanoparticles, and improve the signal-to-noise ratio for time-gated cellular imaging. PVK=poly(9-vinylcarbazole). Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Translocation and biokinetic behavior of nanoscaled europium oxide particles within 5 days following an acute inhalation in rats.

    Science.gov (United States)

    Creutzenberg, Otto; Kock, Heiko; Schaudien, Dirk

    2016-03-01

    Nanoscaled europium oxide (Eu2O3) particles were inhaled by rats after acute exposure and the potential translocation of particles followed by chemical analysis and transmission electron microscopy (TEM) was investigated. An aqueous dispersion (phosphate buffer/bovine serum albumin) of a commercially available Eu2O3 particle fraction consisting partially of nanoscaled particles was aerosolized with pressurized air. After rapid evaporation, rats inhaled the dry aerosol for 6 h in a single exposure resulting in an alveolar calculated dose of approximately 39.5 μg Eu2O3. Using chemical analysis, 36.8 μg Eu2O3 was detected 1 h after lung inhalation. The amount declined slightly to 34.5 μg after 1 day and 35.0 μg after 5 days. The liver showed an increase of Eu2O3 from 32.3 ng 1 h up to 294 ng 5 days after inhalation. Additionally, lung-associated lymph nodes, thymus, kidneys, heart and testis exhibited an increase of europium over the period investigated. In the blood, the highest amount of europium was found 1 h after treatment whereas feces, urine and mesenteric lymph nodes revealed the highest amount 1 day after treatment. Using TEM analysis, particles could be detected only in lungs, and in the liver, no particles were detectable. In conclusion, the translocation of Eu2O3 within 5 days following inhalation could be determined very precisely by chemical analysis. A translocation of Eu2O3 particulate matter to liver was not detectable by TEM analysis; thus, the overproportional level of 0.8% of the lung load observed in the liver after 5 days suggests a filtering effect of dissolved europium with accumulation. Copyright © 2015 John Wiley & Sons, Ltd.

  8. A Highly Sensitive Europium Nanoparticle-Based Immunoassay for Detection of Influenza A/B Virus Antigen in Clinical Specimens

    Science.gov (United States)

    Zhang, Panhe; Zhao, Jiangqin; Du, Bingchen; Mohan, Haleyurgirisetty; Liu, Jikun; El Mubarak, Haja Sittana; Landry, Marie L.

    2014-01-01

    We report the development of a novel europium nanoparticle-based immunoassay (ENIA) for rapid detection of influenza A and influenza B viruses. The ENIA demonstrated sensitivities of 90.7% (147/162) for influenza A viruses and 81.80% (9/11) for influenza B viruses compared to those for an in-house reverse transcription (RT)-PCR assay in testing of influenza-positive clinical samples. PMID:25297327

  9. Nature of the concentration thresholds of europium atom yield from the oxidized tungsten surface under electron stimulated desorption

    CERN Document Server

    Davydov, S Y

    2002-01-01

    The nature of the electron-stimulated desorption (ESD) of the europium atoms by the E sub e irradiating electrons energies, equal to 50 and 80 eV, as well as peculiarities of the Eu atoms yield dependence on their concentration on the oxidized tungsten surface are discussed. It is shown, that the ESD originates by the electron transition from the interval 5p- or 5s shell of the tungsten surface atom onto the oxygen external unfilled 2p-level

  10. Lattice thermal conductivity of silicate glasses at high pressures

    Science.gov (United States)

    Chang, Y. Y.; Hsieh, W. P.

    2016-12-01

    Knowledge of the thermodynamic and transport properties of magma holds the key to understanding the thermal evolution and chemical differentiation of Earth. The discovery of the remnant of a deep magma ocean above the core mantle boundary (CMB) from seismic observations suggest that the CMB heat flux would strongly depend on the thermal conductivity, including lattice (klat) and radiative (krad) components, of dense silicate melts and major constituent minerals around the region. Recent measurements on the krad of dense silicate glasses and lower-mantle minerals show that krad of dense silicate glasses could be significantly smaller than krad of the surrounding solid mantle phases, and therefore the dense silicate melts would act as a thermal insulator in deep lower mantle. This conclusion, however, remains uncertain due to the lack of direct measurements on the lattice thermal conductivity of silicate melts under relevant pressure-temperature conditions. Besides the CMB, magmas exist in different circumstances beneath the surface of the Earth. Chemical compositions of silicate melts vary with geological and geodynamic settings of the melts and have strong influences on their thermal properties. In order to have a better view of heat transport within the Earth, it is important to study compositional and pressure dependences of thermal properties of silicate melts. Here we report experimental results on lattice thermal conductivities of silicate glasses with basaltic and rhyolitic compositions up to Earth's lower mantle pressures using time-domain thermoreflectance coupled with diamond-anvil cell techniques. This study not only provides new data for the thermal conductivity of silicate melts in the Earth's deep interior, but is crucial for further understanding of the evolution of Earth's complex internal structure.

  11. Ultrasmall Superparamagnetic Iron Oxide Nanoparticles with Europium(III) DO3A as a Bimodal Imaging Probe.

    Science.gov (United States)

    Carron, Sophie; Bloemen, Maarten; Vander Elst, Luce; Laurent, Sophie; Verbiest, Thierry; Parac-Vogt, Tatjana N

    2016-03-18

    A new prototype consisting of ultrasmall superparamagnetic iron oxide (USPIO) nanoparticles decorated with europium(III) ions encapsulated in a DO3A organic scaffold was designed as a platform for further development of bimodal contrast agents for MRI and optical imaging. The USPIO nanoparticles act as negative MRI contrast agents, whereas the europium(III) ion is a luminophore that is suitable for use in optical imaging detection. The functionalized USPIO nanoparticles were characterized by TEM, DLS, XRD, FTIR, and TXRF analysis, and a full investigation of the relaxometric and optical properties was conducted. The typical luminescence emission of europium(III) was observed and the main red emission wavelength was found at 614 nm. The relaxometric study of these ultrasmall nanoparticles showed r2 values of 114.8 mM(-1) Fes(-1) at 60 MHz, which is nearly double the r2 relaxivity of Sinerem(®). © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. A lysosome targetable luminescent bioprobe based on a europium β-diketonate complex for cellular imaging applications.

    Science.gov (United States)

    George, T M; Krishna, Mahesh S; Reddy, M L P

    2016-11-22

    Herein, we report a novel lysosome targetable luminescent bioprobe derived from a europium coordination compound, namely Eu(pfphOCH3IN)3(DDXPO) 4 [where HpfphOCH3IN = 4,4,5,5,5-pentafluoro-3-hydroxy-1-(1-(4-methoxyphenyl)-1H-indol-3-yl)pent-2-en-1-one and DDXPO = 4,5-bis(diphenylphosphino)-9,9-dimethylxanthene oxide]. Notably, the newly designed europium complex exhibits significant quantum yield (Φoverall = 25 ± 3%) and 5D0 excited state lifetime (τ = 398 ± 3 μs) values under physiological pH (7.2) conditions when excited at 405 nm. Hence the developed europium complex has been evaluated for live cell imaging applications using mouse pre-adipocyte cell lines (3T3L1). Colocalization studies of the designed bio-probe with commercial Lysosome-GFP in 3T3L1 cells demonstrated the specific localization of the probe in the lysosome with a high colocalization coefficient (A = 0.83). Most importantly, the developed bioprobe exhibits good cell permeability, photostability and non-cytotoxicity.

  13. Mössbauer spectroscopy of europium-doped fluorochlorozirconate glasses and glass ceramics: optimization of storage phosphors in computed radiography.

    Science.gov (United States)

    Pfau, C; Paßlick, C; Gray, S K; Johnson, J A; Johnson, C E; Schweizer, S

    2013-05-22

    Eu(2+)-doped fluorochlorozirconate (FCZ) glasses and glass ceramics, which are being developed for medical and photovoltaic applications, have been analysed by Mössbauer spectroscopy. The oxidation state and chemical environment of the europium ions, which are important for the performance of these materials, were investigated. Routes for maximizing the divalent europium content were also investigated. By using EuCl2 instead of EuF2 in the starting material a fraction of about 90% of the europium was maintained in the Eu(2+) state as opposed to about 70% when using EuF2. The glass ceramics produced by subsequent thermal processing contain BaCl2 nanocrystals in which Eu(2+) is incorporated, as shown by the narrower linewidth in the Mössbauer spectrum. Debye temperatures of 147 K and 186 K for Eu(2+) and Eu(3+), respectively, were determined from temperature dependent Mössbauer measurements. The f-factors were used to obtain the Eu(2+)/Eu(3+) ratio from the area ratio of the corresponding absorption lines.

  14. Viscosity of Heterogeneous Silicate Melts: A Non-Newtonian Model

    Science.gov (United States)

    Liu, Zhuangzhuang; Blanpain, Bart; Guo, Muxing

    2017-12-01

    The recently published viscosity data of heterogeneous silicate melts with well-documented structure and experimental conditions are critically re-analyzed and tabulated. By using these data, a non-Newtonian viscosity model incorporating solid fraction, solid shape, and shear rate is proposed on the basis of the power-law equation. This model allows calculating the viscosity of the heterogeneous silicate melts with solid fraction up to 34 vol pct. The error between the calculated and measured data is evaluated to be 32 pct, which is acceptable considering the large error in viscosity measurement of the completely liquid silicate melt.

  15. Fire Resistance of Wood Impregnated with Soluble Alkaline Silicates

    Directory of Open Access Journals (Sweden)

    Carlos Alberto Giudice

    2007-01-01

    Full Text Available The aim of this paper is to determine the fire performance of wood panels (Araucaria angustifolia impregnated with soluble alkaline silicates. Commercial silicates based on sodium and potassium with 2.5/1.0 and 3.0/1.0 silica/alkali molar ratios were selected; solutions and glasses were previously characterized. Experimental panels were tested in a limiting oxygen chamber and in a two-foot tunnel. Results displayed a high fire-retardant efficiency using some soluble silicates.

  16. Mechanistic study and modeling of radionuclides retention by the hydrated calcium silicates (HCS) of cements; Etude mecanistique et modelisation de la retention de radionucleides par les silicates de calcium hydrates (CSH) des ciments

    Energy Technology Data Exchange (ETDEWEB)

    Pointeau, I

    2000-09-01

    This work attempts to investigate the modelling of radioisotopes (Cs{sup +}, Pb{sup 2+}, Eu{sup 3+}) immobilization in cement matrix, in the frame of the design of engineered barrier of a deep radwaste repository. The model development concept consists of three major steps: - surface chemistry modelling of the calcium silicate hydrate CSH, used to simulate hydrated cement behaviour; - solid analysis of the batch sorption experiments: identification of the uptake mechanism; - both previous steps are used, with isotherm data, in the modelling of the radioisotopes immobilization in the CSH matrix. Final results: (all modelling are available for all the range of studied Ca/Si ratios and have been validated with predictive calculations). - A thermodynamic modelling of the CSH surface chemistry has been developed. The labile calcium and proton sorption constants on silanol sites (>SiOH) have been extracted. - Cs{sup +} is sorbed on two sites. The silanol site (weak site) has a high site density (10 sites.nm{sup -2}), which accounts for the CSH unsaturation in high [CS{sup +}]. A strong site is also identified. - Pb{sup 2+} immobilization in CSH matrix is modelled with surface equilibria and solubility equilibrium. - Eu{sup 3+} fixation has been investigated with solid analysis: Site-Selective anti Time-Resolved Luminescence Spectroscopy, XPS and SEM-EDS. Eu{sup 3+} thus does not precipitate in CSH water but is sorbed on the CSH surface (high hydroxylated environment). Europium is also (minority site) inserted in the CSH framework. (author)

  17. Conversion of rice hull ash into soluble sodium silicate

    Directory of Open Access Journals (Sweden)

    Edson Luiz Foletto

    2006-09-01

    Full Text Available Sodium silicate is used as raw material for several purposes: silica gel production, preparation of catalysts, inks, load for medicines, concrete hardening accelerator, component of detergents and soaps, refractory constituent and deflocculant in clay slurries. In this work sodium silicate was produced by reacting rice hull ash (RHA and aqueous sodium hydroxide, in open and closed reaction systems. The studied process variables were time, temperature of reaction and composition of the reaction mixture (expressed in terms of molar ratios NaOH/SiO2 and H2O/SiO2. About 90% silica conversion contained in the RHA into sodium silicate was achieved in closed system at 200 °C. The results showed that sodium silicate production from RHA can generate aggregate value to this residue.

  18. Study of thermal effects of silicate-containing hydroxyapatites

    Science.gov (United States)

    Golovanova, O. A.; Zaits, A. V.; Berdinskaya, N. V.; Mylnikova, T. S.

    2016-02-01

    The possibility of modifications of hydroxyapatite silicate ions, from the extracellular fluid prototype solution under near-physiological conditions has been studied. Formation of silicon-structured hydroxyapatite with different extent of substitution of phosphate groups in the silicate group has been established through chemical and X-ray diffraction analyses, FTIR spectroscopy and optical microscopy. The results obtained are in agreement and suggest the possibility of substitution of phosphate groups for silicate groups in the hydroxyapatite structure when introducing different sources of silica, tetraethoxysilane and sodium silicate, in the reaction mixture. Growth in the amount of silicon in Si-HA results in the increase in the thermal stability of the samples. The greatest mass loss occurs at temperatures in the range of 25-400 0C that is caused by the removal of the crystallization and adsorption water and volatile impurities. It is shown that the modified apatites are of imperfect structure and crystallize in a nanocrystalline state.

  19. Silicate Urolithiasis during Long-Term Treatment with Zonisamide

    Directory of Open Access Journals (Sweden)

    Satoru Taguchi

    2013-01-01

    Full Text Available Silicate urinary calculi are rare in humans, with an incidence of 0.2% of all urinary calculi. Most cases were related to excess ingestion of silicate, typically by taking magnesium trisilicate as an antacid for peptic ulcers over a long period of time; however, there also existed unrelated cases, whose mechanism of development remains unclear. On the other hand, zonisamide, a newer antiepileptic drug, is one of the important causing agents of iatrogenic urinary stones in patients with epilepsy. The supposed mechanism is that zonisamide induces urine alkalinization and then promotes crystallization of urine components such as calcium phosphate by inhibition of carbonate dehydratase in renal tubular epithelial cells. Here, we report a case of silicate urolithiasis during long-term treatment with zonisamide without magnesium trisilicate intake and discuss the etiology of the disease by examining the silicate concentration in his urine.

  20. Tris (catecholato) silicates of nickel: Synthesis, characterization and ...

    Indian Academy of Sciences (India)

    catecholato)silicates of nickel: Synthesis, characterization and first observation of inter-ion ligand transfer. J Vijeyakumar Kingston G S M Sundaram M N Sudheendra Rao. Volume 112 Issue 3 June 2000 pp 402-402 ...

  1. Optical Characterization of Nano- and Microcrystals of EuPO₄ Created by One-Step Synthesis of Antimony-Germanate-Silicate Glass Modified by P₂O₅.

    Science.gov (United States)

    Zmojda, Jacek; Kochanowicz, Marcin; Miluski, Piotr; Baranowska, Agata; Pisarski, Wojciech A; Pisarska, Joanna; Jadach, Renata; Sitarz, Maciej; Dorosz, Dominik

    2017-09-09

    Technology of active glass-ceramics (GC) is an important part of luminescent materials engineering. The classic method to obtain GC is based on annealing of parent glass in proper temperature and different time periods. Generally, only the bulk materials are investigated as a starting host for further applications. However, the effect of an additional heat-treatment process on emission and structural properties during GC processing is omitted. Here, we focus on the possibility of obtaining transparent glass-ceramic doped with europium ions directly with a melt-quenching method. The influence of phosphate concentration (up to 10 mol %) on the inversion symmetry of local environment of Eu3+ ions in antimony-germanate-silicate (SGS) glass has been investigated. The Stark splitting of luminescence spectra and the local asymmetry ratio estimated by relation of (⁵D₀→⁷F₂)/(⁵D₀→⁷F₁) transitions in fabricated glass confirms higher local symmetry around Eu3+ ions. Based on XRD and SEM/EDX measurements, the EuPO₄ nano- and microcrystals with monoclinic geometry were determined. Therefore, in our experiment, we confirmed possibility of one-step approach to fabricate crystalline structures (glass-ceramic) in Eu-doped SGS glass without additional annealing process.

  2. Conversion of rice hull ash into soluble sodium silicate

    OpenAIRE

    Edson Luiz Foletto; Ederson Gratieri; Leonardo Hadlich de Oliveira; Sérgio Luiz Jahn

    2006-01-01

    Sodium silicate is used as raw material for several purposes: silica gel production, preparation of catalysts, inks, load for medicines, concrete hardening accelerator, component of detergents and soaps, refractory constituent and deflocculant in clay slurries. In this work sodium silicate was produced by reacting rice hull ash (RHA) and aqueous sodium hydroxide, in open and closed reaction systems. The studied process variables were time, temperature of reaction and composition of the reacti...

  3. Comparison of silicon nanoparticles and silicate treatments in fenugreek.

    Science.gov (United States)

    Nazaralian, Sanam; Majd, Ahmad; Irian, Saeed; Najafi, Farzaneh; Ghahremaninejad, Farrokh; Landberg, Tommy; Greger, Maria

    2017-06-01

    Silicon (Si) fertilization improves crop cultivation and is commonly added in the form of soluble silicates. However, most natural plant-available Si originates from plant formed amorphous SiO2 particles, phytoliths, similar to SiO2-nanoparticles (SiNP). In this work we, therefore, compared the effect by sodium silicate and that of SiNP on Si accumulation, activity of antioxidative stress enzymes catalase, peroxidase, superoxide dismutase, lignification of xylem cell walls and activity of phenylalanine ammonia-lyase (PAL) as well as expression of genes for the putative silicon transporter (PST), defensive (Tfgd 1) and phosphoenolpyruvate carboxykinase (PEPCK) and protein in fenugreek (Trigonella foenum-graecum L.) grown in hydroponics. The results showed that Si was taken up from both silicate and SiNP treatments and increasing sodium silicate addition increased the translocation of Si to the shoot, while this was not shown with increasing SiNP addition. The silicon transporter PST was upregulated at a greater level when sodium silicate was added compared with SiNP addition. There were no differences in effects between sodium silicate and SiNP treatments on the other parameters measured. Both treatments increased the uptake and accumulation of Si, xylem cell wall lignification, cell wall thickness, PAL activity and protein concentration in seedlings, while there was no effect on antioxidative enzyme activity. Tfgd 1 expression was strongly downregulated in leaves at Si addition. The similarity in effects by silicate and SiNP would be due to that SiNP releases silicate, which may be taken up, shown by a decrease in SiNP particle size with time in the medium. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  4. Effects of silicate application on soil fertility and wheat yield

    Directory of Open Access Journals (Sweden)

    Marcos Vinícius Mansano Sarto

    2015-12-01

    Full Text Available An improvement in soil chemical properties and crop development with silicate application has been confirmed in several plant species. The effects of silicate application on soil chemical properties and wheat growth were investigated in the present study. The experiment was carried out in 8-L plastic pots in a greenhouse. Treatments were arranged in a randomized block design in a 3 × 5 factorial: three soils [Rhodic Acrudox (Ox1, Rhodic Hapludox (Ox2 and Arenic Hapludult (Ult] and five silicate rates (0, 1, 2, 4 and 6 Mg ha–1 of calcium/magnesium silicate, with four replications. The plant length, number of spikes per pot, shoot dry matter and grain yield, were measured after 115 days of wheat (Triticum aestivum L. growth. Changes in the soil chemical properties (pH, H+ + Al3+, Al3+, P, K, Ca, Mg, Si, Cu, Zn, Fe and Mn were analyzed after wheat harvest. Application of calcium/magnesium silicate reduces the potential acidity (H+ + Al3+ and Al3+ phytotoxic; and increases the soil pH, available Ca, Mg and Si, cation exchange capacity (CEC and soil base saturation. Silicate application did not affect the available P, exchangeable K and availability of micronutrients (Cu, Zn, Fe and Mn in the three soils. The application of calcium/magnesium silicate in an acid clayey Rhodic Hapludox improves the development and yield of wheat; however, the silicate application in soil with pH higher to 5.3 and high Si availability does not affect the agronomic characteristics and grain yield of wheat. 

  5. History of Nebular Processing Traced by Silicate Stardust in IDPS

    Science.gov (United States)

    Messenger, Scott R.; Keller, L. P.; Nakamura-Messenger, K.

    2010-01-01

    Chondritic porous interplanetary dust particles (CP-IDPs) may be the best preserved remnants of primordial solar system materials, in part because they were not affected by parent body hydrothermal alteration. Their primitive characteristics include fine grained, unequilibrated, anhydrous mineralogy, enrichment in volatile elements, and abundant molecular cloud material and silicate stardust. However, while the majority of CP-IDP materials likely derived from the Solar System, their formation processes and provenance are poorly constrained. Stardust abundances provide a relative measure of the extent of processing that the Solar System starting materials has undergone in primitive materials. For example, among primitive meteorites silicate stardust abundances vary by over two orders of magnitude (less than 10-200 ppm). This range of abundances is ascribed to varying extents of aqueous processing in the meteorite parent bodies. The higher average silicate stardust abundances among CP-IDPs (greater than 375 ppm) are thus attributable to the lack of aqueous processing of these materials. Yet, silicate stardust abundances in IDPs also vary considerably. While the silicate stardust abundance in IDPs having anomalous N isotopic compositions was reported to be 375 ppm, the abundance in IDPs lacking N anomalies is less than 10 ppm. Furthermore, these values are significantly eclipsed among some IDPs with abundances ranging from 2,000 ppm to 10,000 ppm. Given that CP-IDPs have not been significantly affected by parent body processes, the difference in silicate stardust abundances among these IDPs must reflect varying extents of nebular processing. Here we present recent results of a systematic coordinated mineralogical/isotopic study of large cluster IDPs aimed at (1) characterizing the mineralogy of presolar silicates and (2) delineating the mineralogical and petrographic characteristics of IDPs with differing silicate stardust abundances. One of the goals of this study is

  6. Fast and Selective Preconcentration of Europium from Wastewater and Coal Soil by Graphene Oxide/Silane@Fe3O4 Dendritic Nanostructure.

    Science.gov (United States)

    Patra, Santanu; Roy, Ekta; Madhuri, Rashmi; Sharma, Prashant K

    2015-05-19

    In this study, nanocomposite of graphene oxide and silane modified magnetic nanoparticles (silane@Fe3O4) were synthesized in a form of dendritic structure. For this, silane@Fe3O4 nanoparticle gets sandwiched between two layers of graphene oxide by chemical synthesis route. The synthesized dendritic structure was used as a monomer for synthesis of europium ion imprinted polymer. The synthesis of imprinted polymer was contemplated onto the surface of the vinyl group modified silica fiber by activated generated free radical atom-transfer radical polymerization, that is, AGET-ATRP technique. The synthesized dendritic monomer was characterized by XRD, FT-IR, VSM, FE-SEM, and TEM analyses. The imprinted polymer modified silica fiber was first validated in the aqueous and blood samples for successful extraction and detection of europium ion with limit of detection = 0.050 pg mL(-1) (signal/noise = 3). The imprinted polymer modified silica fiber was also used for preconcentration and separation of europium metal ion from various soil samples of coal mine areas. However, the same silica fiber was also used for wastewater treatment and shows 100% performance for europium removal. The findings herein suggested that dendritic nanocomposite could be potentially used as a highly effective material for the enrichment and preconcentration of europium or other trivalent lanthanides/actinides in nuclear waste management.

  7. Development of europium doped core-shell silica cobalt ferrite functionalized nanoparticles for magnetic resonance imaging.

    Science.gov (United States)

    Kevadiya, Bhavesh D; Bade, Aditya N; Woldstad, Christopher; Edagwa, Benson J; McMillan, JoEllyn M; Sajja, Balasrinivasa R; Boska, Michael D; Gendelman, Howard E

    2017-02-01

    The size, shape and chemical composition of europium (Eu3+) cobalt ferrite (CFEu) nanoparticles were optimized for use as a "multimodal imaging nanoprobe" for combined fluorescence and magnetic resonance bioimaging. Doping Eu3+ ions into a CF structure imparts unique bioimaging and magnetic properties to the nanostructure that can be used for real-time screening of targeted nanoformulations for tissue biodistribution assessment. The CFEu nanoparticles (size ∼7.2nm) were prepared by solvothermal techniques and encapsulated into poloxamer 407-coated mesoporous silica (Si-P407) to form superparamagnetic monodisperse Si-CFEu nanoparticles with a size of ∼140nm. Folic acid (FA) nanoparticle decoration (FA-Si-CFEu, size ∼140nm) facilitated monocyte-derived macrophage (MDM) targeting. FA-Si-CFEu MDM uptake and retention was higher than seen with Si-CFEu nanoparticles. The transverse relaxivity of both Si-CFEu and FA-Si-CFEu particles were r2=433.42mM-1s-1 and r2=419.52mM-1s-1 (in saline) and r2=736.57mM-1s-1 and r2=814.41mM-1s-1 (in MDM), respectively. The results were greater than a log order-of-magnitude than what was observed at replicate iron concentrations for ultrasmall superparamagnetic iron oxide (USPIO) particles (r2=31.15mM-1s-1 in saline) and paralleled data sets obtained for T2 magnetic resonance imaging. We now provide a developmental opportunity to employ these novel particles for theranostic drug distribution and efficacy evaluations. A novel europium (Eu3+) doped cobalt ferrite (Si-CFEu) nanoparticle was produced for use as a bioimaging probe. Its notable multifunctional, fluorescence and imaging properties, allows rapid screening of future drug biodistribution. Decoration of the Si-CFEu particles with folic acid increased its sensitivity and specificity for magnetic resonance imaging over a more conventional ultrasmall superparamagnetic iron oxide particles. The future use of these particles in theranostic tests will serve as a platform for

  8. Tuning Eu{sup 3+} emission in europium sesquioxide films by changing the crystalline phase

    Energy Technology Data Exchange (ETDEWEB)

    Mariscal, A., E-mail: antonio.mariscal@csic.es [Laser Processing Group, Instituto de Óptica, CSIC, C/ Serrano 121, 28006 Madrid (Spain); Quesada, A. [Ceramics for Smart Systems Group, Instituto de Cerámica y Vidrio, C/ Kelsen 5, 28049 Madrid (Spain); Camps, I. [Laser Processing Group, Instituto de Óptica, CSIC, C/ Serrano 121, 28006 Madrid (Spain); Palomares, F.J. [Instituto de Ciencia de Materiales de Madrid, C/ Sor Juana Inés de la Cruz 3, 28049 Madrid (Spain); Fernández, J.F. [Ceramics for Smart Systems Group, Instituto de Cerámica y Vidrio, C/ Kelsen 5, 28049 Madrid (Spain); Serna, R. [Laser Processing Group, Instituto de Óptica, CSIC, C/ Serrano 121, 28006 Madrid (Spain)

    2016-06-30

    Highlights: • PLD production of high quality europium sesquioxide (Eu{sub 2}O{sub 3}) films. • The deposition of Al{sub 2}O{sub 3} capping and/or buffer layers modifies the crystallization for Eu{sub 2}O{sub 3} films upon annealing. • The formation of cubic or monoclinic phases can be favored. • Eu{sup 3+} emission tuning is achieved as a consequence of crystal field effects. - Abstract: We report the growth of europium sesquioxide (Eu{sub 2}O{sub 3}) thin films by pulsed laser deposition (PLD) in vacuum at room temperature from a pure Eu{sub 2}O{sub 3} ceramic bulk target. The films were deposited in different configurations formed by adding capping and/or buffer layers of amorphous aluminum oxide (a-Al{sub 2}O{sub 3}). The optical properties, refractive index and extinction coefficient of the as deposited Eu{sub 2}O{sub 3} layers were obtained. X-ray photoelectron spectroscopy (XPS) measurements were done to assess its chemical composition. Post-deposition annealing was performed at 500 °C and 850 °C in air in order to achieve the formation of crystalline films and to accomplish photoluminescence emission. According to the analysis of X-ray diffraction (XRD) spectra, cubic and monoclinic phases were formed. It is found that the relative amount of the phases is related to the different film configurations, showing that the control over the crystallization phase can be realized by adequately designing the structures. All the films showed photoluminescence emission peaks (under excitation at 355 nm) that are attributed to the intra 4f-transitions of Eu{sup 3+} ions. The emission spectral shape depends on the crystalline phase of the Eu{sub 2}O{sub 3} layer. Specifically, changes in the hypersensitive {sup 5}D{sub 0} → {sup 7}F{sub 2} emission confirm the strong influence of the crystal field effect on the Eu{sup 3+} energy levels.

  9. Silicates in orthopedics and bone tissue engineering materials.

    Science.gov (United States)

    Zhou, Xianfeng; Zhang, Nianli; Mankoci, Steven; Sahai, Nita

    2017-07-01

    Following the success of silicate-based glasses as bioactive materials, silicates are believed to play important roles in promoting bone formation and have therefore been considered to provide a hydroxyapatite (HAP) surface layer capable of binding to bone as well as potentially being a pro-osteoinductive factor. Natural silicate minerals and silicate-substituted HAPs are also being actively investigated as orthopaedic bone and dental biomaterials for application in tissue engineering. However, the mechanisms for the proposed roles of silicate in these materials have not been fully understood and are controversial. Here, we review the potential roles of silicate for bone tissue engineering applications and recent breakthroughs in identifying the cellular-level molecular mechanisms for the osteoinductivity of silica. The goal of this article is to inspire new ideas for the rational design of third-generation cell-and gene-affecting biomaterials. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 2090-2102, 2017. © 2017 Wiley Periodicals, Inc.

  10. On the Mg/Fe Ratio in Silicate Minerals in the Circumstellar Environments I. The Mg/Fe Ratio in Silicate Mineral Constituents of the Kaba Meteorite

    Science.gov (United States)

    Futó, P.

    2017-11-01

    The moderately high ratio of Mg in the silicates of the solar environment indicates that Mg-rich silicates are likely to be frequent in the interstellar medium and the circumstellar environments in case of chondritic-like composition.

  11. Potassium silicate and calcium silicate on the resistance of soybean to Phakopsora pachyrhizi infection

    Directory of Open Access Journals (Sweden)

    Maria Fernanda Cruz

    2013-01-01

    Full Text Available The control of Asian Soybean Rust (ASR, caused by Phakopsora pachyrhizi, has been difficult due to the aggressiveness of the pathogen and the lack of resistant cultivars. The objective of this study was to evaluate the effects of spray of potassium silicate (PS and soil amendment with calcium silicate (CS on soybean resistance to ASR. The PS solution was sprayed to leaves 24 hours prior to fungal inoculation while CS was amended to the soil at thirty-five days before sowing. The infection process of P. pachyrhizi was investigated by scanning electron microscopy. The uredia on leaves of plants sprayed with PS were smaller and more compact than those observed on the leaves of plants grown in soil amended with CS or in soil non-amended with CS (control treatment. On leaves of plants from the control treatment, uredia produced many urediniospores at 9 days after inoculation, and the ASR severity was 15, 8 and 9%, respectively, for plants from control, PS and CS treatments. In conclusion, the spray of PS contributed to reduce the number of uredia per cm² of leaf area and both PS spray and CS resulted in lower ASR symptoms.

  12. Viscoelastic properties of polymer based layered-silicate nanocomposites

    Science.gov (United States)

    Ren, Jiaxiang

    Polymer based layered-silicate nanocomposites offer the potential for dramatically improved mechanical, thermal, and barrier properties while keeping the material density low. Understanding the linear and non-linear viscoelastic response for such materials is crucial because of the ability of such measurements to elucidate the mesoscale dispersion of layered-silicates and changes in such dispersion to applied flows as would be encountered in processing of these materials. A series of intercalated polystyrene (and derivatives of polystyrene) layered-silicate nanocomposites are studied to demonstrate the influence of mesoscale dispersion and organic---inorganic interactions on the linear and non-linear viscoelastic properties. A layered-silicate network structure is exhibited for the nanocomposites with strong polymer-silicate interaction such as montmorillonite (2C18M) and fluorohectorite (C18F) and the percolation threshold is ˜ 6 wt % for the 2C18M based hybrids. However, the nanocomposites based on hectorite (2C18H) with weak polymer-silicate interaction exhibit liquid-like terminal zone behavior. Furthermore, the enhanced terminal zone elastic modulus and viscosity of high brominated polystyrene and high molecular weight polystyrene based 2C18M nanocomposites suggest an improved delamination and dispersion of layered-silicates in the polymer matrix. The non-linear viscoelastic properties, specifically, the non-linear stress relaxation behavior and the applicability of time---strain separability, the effect of increasing strain amplitude on the oscillatory shear flow properties, and the shear rate dependence of the steady shear flow properties are examined. The silicate sheets (or collections of sheets) exhibit the ability to be oriented by the applied flow. Experimentally, the empirical Cox - Merz rule is demonstrated to be inapplicable for the hybrids. Furthermore, the K-BKZ constitutive model is used to model the steady shear properties. While being able to

  13. Highly efficient precipitation of phosphoproteins using trivalent europium, terbium, and erbium ions

    Energy Technology Data Exchange (ETDEWEB)

    Guezel, Yueksel; Rainer, Matthias; Mirza, Munazza Raza; Bonn, Guenther K. [Leopold-Franzens University, Institute of Analytical Chemistry and Radiochemistry, Innsbruck (Austria)

    2012-05-15

    This study describes a highly efficient method for the selective precipitation of phosphoproteins by trivalent europium, terbium, and erbium metal ions. These metal cations belong to the group of lanthanides and are known to be hard acceptors with an overwhelming preference for oxygen-containing anions such as phosphates to which they form very tight ionic bonds. The method could be successfully applied to specifically precipitate phosphoproteins from complex samples including milk and egg white by forming solid metal-protein complexes. Owing to the low solubility product of the investigated lanthanide salts, the produced metal-protein complexes showed high stability. The protein pellets were extensively washed to remove nonphosphorylated proteins and contaminants. For the analysis of proteins the pellets were first dissolved in 30 % formic acid and subjected to matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) MS. For peptide mass-fingerprint analysis the precipitated phosphoproteins were enzymatically digested using microwave-assisted digestion. The method was found to be highly specific for the isolation and purification of phosphoproteins. Protein quantification was performed by colorimetric detection of total precipitated phosphoproteins and revealed more than 95 % protein recovery for each lanthanide salt. (orig.)

  14. Effects of europium polyoxometalate encapsulated in silica nanoparticles (nanocarriers) in soil invertebrates

    Science.gov (United States)

    Bicho, Rita C.; Soares, Amadeu M. V. M.; Nogueira, Helena I. S.; Amorim, Mónica J. B.

    2016-12-01

    Polyoxometalates (POMs) are metal oxo clusters that have been investigated for several applications in material sciences, catalysis, and biomedicine; these gained increasing interest in the field of nanotechnology as nanocarriers for drug delivery. Associated to the increasing applications, there is the need for information regarding the effects on the environment of these compounds, which is completely absent in the literature. In the present study, the effects of europium polyoxometalates encapsulated into silica nanoparticles (Eu-POM/SiO2 NPs) were assessed on the soil representative Enchytraeus crypticus. The individual materials were also assessed (Eu-POMs and SiO2 NPs). Toxicity was evaluated in various test media with increasing complexity: water, soil/water extracts, and soil. Toxicity was only observed for Eu-POM/SiO2 NPs and in the presence of soil components. Despite the fact that effects were observed for concentrations higher than current predicted environmental concentration (PEC), attention should be given to the growing use of these compounds. The present study shows the importance of assessing the effects in soil media, also compared to water. Moreover, results of "no effect" are critically needed and often unpublished. The present study can contribute to the improvement of the OECD guidelines for safety of manufactured nanomaterials on environmental toxicity in the soil compartment providing an improved test alternative.

  15. Spectral Interferences Manganese (Mn) - Europium (Eu) Lines in X-Ray Fluorescence Spectrometry Spectrum

    Science.gov (United States)

    Tanc, Beril; Kaya, Mustafa; Gumus, Lokman; Kumral, Mustafa

    2016-04-01

    X-ray fluorescence (XRF) spectrometry is widely used for quantitative and semi quantitative analysis of many major, minor and trace elements in geological samples. Some advantages of the XRF method are; non-destructive sample preparation, applicability for powder, solid, paste and liquid samples and simple spectrum that are independent from chemical state. On the other hand, there are some disadvantages of the XRF methods such as poor sensitivity for low atomic number elements, matrix effect (physical matrix effects, such as fine versus course grain materials, may impact XRF performance) and interference effect (the spectral lines of elements may overlap distorting results for one or more elements). Especially, spectral interferences are very significant factors for accurate results. In this study, semi-quantitative analyzed manganese (II) oxide (MnO, 99.99%) was examined. Samples were pelleted and analyzed with XRF spectrometry (Bruker S8 Tiger). Unexpected peaks were obtained at the side of the major Mn peaks. Although sample does not contain Eu element, in results 0,3% Eu2O3 was observed. These result can occur high concentration of MnO and proximity of Mn and Eu lines. It can be eliminated by using correction equation or Mn concentration can confirm with other methods (such as Atomic absorption spectroscopy). Keywords: Spectral Interferences; Manganese (Mn); Europium (Eu); X-Ray Fluorescence Spectrometry Spectrum.

  16. Performance of fluorescent europium(III) nanoparticles and colloidal gold reporters in lateral flow bioaffinity assay.

    Science.gov (United States)

    Juntunen, Etvi; Myyryläinen, Tiina; Salminen, Teppo; Soukka, Tero; Pettersson, Kim

    2012-09-01

    Lateral flow (LF) immunoassays (i.e., immunochromatographic assays) have traditionally been applied to analytes that do not require very high analytical sensitivity or quantitative results. The selection of potential analytes is often limited by the performance characteristics of the assay technology. Analytes with more demanding sensitivity requirements call for reporter systems enabling high analytical sensitivity. In this study, we systematically compared the performance of fluorescent europium(III) [Eu(III)] chelate dyed polystyrene nanoparticles and colloidal gold particles in lateral flow assays. The effect of time-resolved measurement mode was also studied. Because binder molecules used in immunoassays might not behave similarly when conjugated to different reporter particles, two model assays were constructed to provide reliable technical comparison of the two reporter systems. The comparative experiment demonstrated that the fluorescent nanoparticles yielded 7- and 300-fold better sensitivity compared with colloidal gold in the two test systems, respectively. Although the two reporter particles may induce variable effects using individual binders, overall the high specific activity of Eu(III) nanoparticles has superior potential over colloidal gold particles for the development of robust high-sensitivity bioaffinity assays. Copyright © 2012 Elsevier Inc. All rights reserved.

  17. Carbon nanotube-loaded Nafion film electrochemical sensor for metal ions: europium.

    Science.gov (United States)

    Wang, Tingting; Zhao, Daoli; Guo, Xuefei; Correa, Jaime; Riehl, Bill L; Heineman, William R

    2014-05-06

    A Nafion film loaded with novel catalyst-free multiwalled carbon nanotubes (MWCNTs) was used to modify a glassy carbon (GC) electrode to detect trace concentrations of metal ions, with europium ion (Eu(3+)) as a model. The interaction between the sidewalls of MWCNTs and the hydrophobic backbone of Nafion allows the MWCNTs to be dispersed in Nafion, which was then coated as a thin film on the GC electrode surface. The electrochemical response to Eu(3+) was found to be ∼10 times improved by MWCNT concentrations between 0.5 and 2 mg/mL, which effectively expanded the electrode surface into the Nafion film and thereby reduced the diffusion distance of Eu(3+) to the electrode surface. At low MWCNT concentrations of 0.25 and 0.5 mg/mL, no significant improvement in signal was obtained compared with Nafion alone. Scanning electron microscopy and electrochemical impedance spectroscopy were used to characterize the structure of the MWCNT-Nafion film, followed by electrochemical characterization with Eu(3+) via cyclic voltammetry and preconcentration voltammetry. Under the optimized conditions, a linear range of 1-100 nM with a calculated detection limit of 0.37 nM (signal/noise = 3) was obtained for determination of Eu(3+) by Osteryoung square-wave voltammetry after a preconcentration time of 480 s.

  18. Effects of europium polyoxometalate encapsulated in silica nanoparticles (nanocarriers) in soil invertebrates

    Energy Technology Data Exchange (ETDEWEB)

    Bicho, Rita C., E-mail: ritabicho@ua.pt; Soares, Amadeu M.V.M. [Universidade de Aveiro, Departamento de Biologia & CESAM (Portugal); Nogueira, Helena I.S. [Universidade de Aveiro, Departamento de Química & CICECO (Portugal); Amorim, Mónica J.B. [Universidade de Aveiro, Departamento de Biologia & CESAM (Portugal)

    2016-12-15

    Polyoxometalates (POMs) are metal oxo clusters that have been investigated for several applications in material sciences, catalysis, and biomedicine; these gained increasing interest in the field of nanotechnology as nanocarriers for drug delivery. Associated to the increasing applications, there is the need for information regarding the effects on the environment of these compounds, which is completely absent in the literature. In the present study, the effects of europium polyoxometalates encapsulated into silica nanoparticles (Eu-POM/SiO{sub 2} NPs) were assessed on the soil representative Enchytraeus crypticus. The individual materials were also assessed (Eu-POMs and SiO{sub 2} NPs). Toxicity was evaluated in various test media with increasing complexity: water, soil/water extracts, and soil. Toxicity was only observed for Eu-POM/SiO{sub 2} NPs and in the presence of soil components. Despite the fact that effects were observed for concentrations higher than current predicted environmental concentration (PEC), attention should be given to the growing use of these compounds. The present study shows the importance of assessing the effects in soil media, also compared to water. Moreover, results of “no effect” are critically needed and often unpublished. The present study can contribute to the improvement of the OECD guidelines for safety of manufactured nanomaterials on environmental toxicity in the soil compartment providing an improved test alternative.

  19. EUROPIUM ION INFLUENCE ON THE FORMATION OF Ag-NANOPARTICLES IN FLUORINE PHOSPHATE GLASSES

    Directory of Open Access Journals (Sweden)

    R. O. Pysh'ev

    2015-05-01

    Full Text Available The paper deals with research of formation characteristics of silver nanoparticles in fluorophosphate glasses 0.25 Na2O - 0.5 P2O5 - 0.10 Ga2O3 - 0.075 AlF3 - 0.025 NaF - 0.05 ZnF2 doped with EuF3 (0.8 and 4 wt.% and without them. The synthesis was carried out in closed glassy carbon crucibles in argon atmosphere. Nanoparticles were formed after a low temperature process of Ag+ → Na+ ion-exchange (320 °C and subsequent heat treatment. It was shown that in the initial glasses doped with EuF3, rare earth ions exist in two valence forms (Eu2+ and Eu3+ in dynamic equilibrium and the concentration of Eu2+ increases proportionally to the total concentration of fluoride. It was shown that sizes of molecular clusters or metal nanoparticles depend on the concentration of europium fluoride and duration of ion exchange. The metallic Ag-nanoparticles sizes were defined for different times of heat treatment and ion exchange. The possibility of the stimulating growth of nanoparticles through the introduction of additional EuF3 in the glass was proved. The possibility of obtaining nanoparticles without the heat treatment in glasses with a high concentration of EuF3 was shown. Chemical mechanism for the formation of Ag-nanoparticles during the ion exchange was suggested.

  20. Nanoparticles in the zirconia-europium niobate system via hydrothermal route.

    Science.gov (United States)

    Hirano, Masanori; Dozono, Hayato

    2013-10-01

    The effect of the composition on the hydrothermal formation, structure, and properties of nanocrystalline luminescent materials in the zirconia (ZrO2)-europium niobate 1/4(Eu3NbO7) system was investigated. In the composition range 40 particles with crystallite size 6.0-7.6 nm that were hydrothermally formed from the precursor solutions of NbCl5, ZrOCI2, and EuCl3 under weakly basic conditions at 240 degrees C showed cubic structure. The lattice parameter when estimated as a single cubic phase linearly decreased as the concentration of ZrO2 increased. The presence of zirconia component effectively promoted the formation of nanocrystals containing the niobate, Eu3NbO7 under hydrothermal condition. The nanocrystalline particles could be excited by ultraviolet light 395 nm (f-f transition) and emitted orange (590 nm) and red light (610 nm) corresponding to 5D0 --> 7F1 and 5D0 --> 7F2 transitions of Eu3+, respectively. The intensity of the electric dipole transition (5D0 --> 7F2) that was expressed in values relative to the magnetic dipole transition (5D0 --> 7F1) increased with increased heat-treatment temperature in the range from 950 to 1200 degrees C.

  1. Photoluminescence of monocrystalline and stain-etched porous silicon doped with high temperature annealed europium

    Energy Technology Data Exchange (ETDEWEB)

    Guerrero-Lemus, R; Montesdeoca-Santana, A; Gonzalez-Diaz, B; Diaz-Herrera, B; Hernandez-Rodriguez, C; Jimenez-Rodriguez, E [Departamento de Fisica Basica, Universidad de La Laguna (ULL), Avenida AstrofIsico Francisco Sanchez, 2. 38206 La Laguna, Tenerife (Spain); Velazquez, J J, E-mail: rglemus@ull.es [Departamento de Fisica Fundamental y Experimental, Electronica y Sistemas, Universidad de La Laguna (ULL), Avenida Astrofisico Francisco Sanchez, 2. 38206 La Laguna, Tenerife (Spain)

    2011-08-24

    In this work, for the first time, the photoluminescent emission and excitation spectra of non-textured layers and stain-etched porous silicon layers (PSLs) doped with high temperature annealed europium (Eu) are evaluated. The PSLs are evaluated as a host for rare earth ions and as an antireflection coating. The applied doping process, which consists in a simple impregnation method followed by a high-temperature annealing step, is compatible with the standard processes in the fabrication of solar cells. The results show down-shifting processes with a maximum photoluminescent intensity at 615 nm, related to the transition {sup 5}D{sub 0} {yields} {sup 7}F{sub 2}. Different initial concentrations of Eu(NO{sub 3}){sub 3} are evaluated to study the influence of the rare earth concentration on the photoluminescent intensity. The chemical composition and the morphology of Eu-doped PSLs are examined by means of x-ray dispersion spectroscopy, Fourier-transform infrared spectroscopy and scanning electron microscopy. These Eu-doped layers are considered to be applied as energy converters in silicon-based third generation solar cells.

  2. Europium (III) and Uranium (VI) complexation by natural organic matter (NOM): Effect of source.

    Science.gov (United States)

    Kautenburger, Ralf; Sander, Jonas M; Hein, Christina

    2017-03-01

    For the safe long-term storage of high-level radioactive waste (HLW), detailed information about geo-chemical behavior of radioactive and toxic metal ions under environmental conditions is important. Natural organic matter (NOM) can play a crucial role in the immobilization or mobilization of these metal ions due to its complexation and colloid formation tendency. In this study, the complexation of europium (as chemical homologue of trivalent actinides such as americium) and uranium (as main component of HLW) by ten humic acids (HA) from different sources and Suwannee NOM river extract has been analyzed. Capillary electrophoresis in combination with inductively coupled plasma mass spectrometry has been used for the evaluation of complex stability constants log β. In order to determine the complex stability constants a conservative single site model was used in this study. In dependence of their source and thus of NOM structure the log β values for the analyzed humic acids are in the range of 6.1-7.0 for Eu(III) and 5.2-6.4 for U(VI) (UO 2 2+ ), respectively. In contrast to the results for HA the used Suwannee river NOM reveals log β values in the range of nearly two orders of magnitude lower (4.6 for Eu 3+ and 4.5 for UO 2 2+ ) under the geochemical conditions applied in this study. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Europium incorporated into titanium oxide by the sol-gel method

    Directory of Open Access Journals (Sweden)

    Lucas Alonso Rocha

    2005-09-01

    Full Text Available In this work titanium sol was prepared from tetraethylorthotitanate (TEOT in ethanol, stabilized with beta-diketonate 2,4 pentanedione in molar ratio 1:1 homogenized by magnetic stirring, europium ion was add as structural probe. The xerogels were heat treated at 500, 750 and 1000 °C and the characterization was realized by x-ray diffraction (XRD, transmission electron microscopy (TEM, thermogravimetric analysis (TGA/DSC and photoluminescence (PL. The excitation spectra of Eu (III ion present maximum in 394 nm correspondent to 5L6 level and emission spectra present bands characteristic transitions arising from the 5 D0 -> 7F J (J = 0, 1, 2, 3, 4 manifolds to samples treat at 500 and 750 °C. The Eu (III emission disappear, when heated at 1000 °C, probably due to phase transition anatase to rutile and migrations of ions to the external surface that was proved by x-ray diffraction, transmission electronic microscopy and the thermogravimetric analyses of xerogels.

  4. Europium Luminescence Used for Logic Gate and Ions Sensing with Enoxacin As the Antenna.

    Science.gov (United States)

    Lu, Lixia; Chen, Chuanxia; Zhao, Dan; Sun, Jian; Yang, Xiurong

    2016-01-19

    Luminescent lanthanide ion complexes have received increasing attention because of their unique optical properties. Herein, we discovered that the luminescence of europium(III) (Eu(3+)) could be regulated by Ag(+) and SCN(-) in seconds with enoxacin (ENX) as the antenna. Under given conditions, only the simultaneous introduction of Ag(+) and SCN(-) could remarkably enhance the luminescence intensity of Eu(3+)-ENX complexes. This phenomenon has been exploited to design an "AND" logic gate and specific luminescence turn-on assays for sensitively sensing Ag(+) and SCN(-) for the first time. Furthermore, the addition of S(2-) resulted in efficient luminescence quenching of the Eu(3+)/ENX/Ag(+)/SCN(-) system due to the strong affinity between Ag(+) and S(2-). Thus, a new luminescent sensing platform for S(2-) was established, which exhibited excellent selectivity and high sensitivity. S(2-) could be detected within the concentration range of 100 nM to 12.5 μM with a detection limit of 60 nM. Such sensing system features simplicity, rapidity, and flexibility. Moreover, this proposed Eu(3+)-based luminescent assay could be successfully applied in the real environmental water sample analysis.

  5. Radiation effects on beta 10.6 of pure and europium doped KCl

    Science.gov (United States)

    Grimes, H. H.; Maisel, J. E.; Hartford, R. H.

    1975-01-01

    Changes in the optical absorption coefficient as a result of X-ray and electron bombardment of pure KCl (monocrystalline and polycrystalline), and divalent europium doped polycrystalline KCl were determined. The optical absorption coefficients were measured by a constant heat flow calorimetric method. Both 300 KV X-irradiation and 2 MeV electron irradiation produced significant increases in beta 10.6, measured at room temperature. The X-irradiation of pure moncrystalline KCl increased beta 10.6 by 0.005/cm for a 113 MR dose. For an equivalent dose, 2 MeV electrons were found less efficient in changing beta 10.6. However, electron irradiation of pure and Eu-doped polycrystalline KCl produced marked increases in adsorption. Beta increased to over 0.25/cm in Eu-doped material for a 30 x 10 to the 14th power electrons/sq cm dose, a factor of 20 increase over unirradiated material. Moreover, bleaching the electron irradiated doped KCl with 649 m light produced and additional factor of 1.5 increase. These findings will be discussed in light of known defect-center properties in KCl.

  6. Accelerating the clearance of mutant huntingtin protein aggregates through autophagy induction by europium hydroxide nanorods.

    Science.gov (United States)

    Wei, Peng-Fei; Zhang, Li; Nethi, Susheel Kumar; Barui, Ayan Kumar; Lin, Jun; Zhou, Wei; Shen, Yi; Man, Na; Zhang, Yun-Jiao; Xu, Jing; Patra, Chitta Ranjan; Wen, Long-Ping

    2014-01-01

    Autophagy is one of the well-known pathways to accelerate the clearance of protein aggregates, which contributes to the therapy of neurodegenerative diseases. Although there are numerous reports that demonstrate the induction of autophagy with small molecules including rapamycin, trehalose and lithium, however, there are few reports mentioning the clearance of aggregate-prone proteins through autophagy induction by nanoparticles. In the present article, we have demonstrated that europium hydroxide [Eu(III)(OH)3] nanorods can reduce huntingtin protein aggregation (EGFP-tagged huntingtin protein with 74 polyQ repeats), responsible for neurodegenerative diseases. Again, we have found that these nanorods induce authentic autophagy flux in different cell lines (Neuro 2a, PC12 and HeLa cells) through the expression of higher levels of characteristic autophagy marker protein LC3-II and degradation of selective autophagy substrate/cargo receptor p62/SQSTM1. Furthermore, depression of protein aggregation clearance through the autophagy blockade has also been observed by using specific inhibitors (wortmannin and chloroquine), indicating that autophagy is involved in the degradation of huntingtin protein aggregation. Since [Eu(III)(OH)3] nanorods can enhance the degradation of huntingtin protein aggregation via autophagy induction, we strongly believe that these nanorods would be useful for the development of therapeutic treatment strategies for various neurodegenerative diseases in near future using nanomedicine approach. Copyright © 2013 Elsevier Ltd. All rights reserved.

  7. High-resolution Thermal Micro-imaging Using Europium Chelate Luminescent Coatings.

    Science.gov (United States)

    Benseman, Timothy M; Hao, Yang; Vlasko-Vlasov, Vitalii K; Welp, Ulrich; Koshelev, Alexei E; Kwok, Wai-Kwong; Divan, Ralu; Keiser, Courtney; Watanabe, Chiharu; Kadowaki, Kazuo

    2017-04-16

    Micro-electronic devices often undergo significant self-heating when biased to their typical operating conditions. This paper describes a convenient optical micro-imaging technique which can be used to map and quantify such behavior. Europium thenoyltrifluoroacetonate (EuTFC) has a 612 nm luminescence line whose activation efficiency drops strongly with increasing temperature, due to T-dependent interactions between the Eu3+ ion and the organic chelating compound. This material may be readily coated on to a sample surface by thermal sublimation in vacuum. When the coating is excited with ultraviolet light (337 nm) an optical micro-image of the 612 nm luminescent response can be converted directly into a map of the sample surface temperature. This technique offers spatial resolution limited only by the microscope optics (about 1 micron) and time resolution limited by the speed of the camera employed. It offers the additional advantages of only requiring comparatively simple and non-specialized equipment, and giving a quantitative probe of sample temperature.

  8. In vivo synthesis of europium selenide nanoparticles and related cytotoxicity evaluation of human cells.

    Science.gov (United States)

    Kim, Eun Bee; Seo, Ji Min; Kim, Gi Wook; Lee, Sang Yup; Park, Tae Jung

    2016-12-01

    Nanotechnology strives to combine new materials for development of noble nanoparticles. As the nanoparticles exhibit unique optical, electronic, and magnetic properties depending on their composition, developing safe, cost-effective and environmentally friendly technologies for the synthesis have become an important issue. In this study, in vivo synthesis of europium selenide (EuSe) nanoparticles was performed using recombinant Escherichia coli cells expressing heavy-metal binding proteins, phytochelatin synthase and metallothionein. The formation of EuSe nanoparticles was confirmed by using UV-vis spectroscopy, spectrofluorometry, X-ray diffraction, energy dispersive X-ray and transmission electron microscopy. The synthesized EuSe nanoparticles exhibited high fluorescence intensities as well as strong magnetic properties. Furthermore, anti-cancer effect of EuSe nanoparticles against cancer cell lines was investigated. This strategy for the biogenic synthesis of nanoparticles has a great potential as bioimaging tools and drug carrying agents in biomedical fields due to its simplicity and nontoxicity. Copyright © 2016 Elsevier Inc. All rights reserved.

  9. Circularly Polarized Luminescence in Enantiopure Europium and Terbium Complexes with Modular, All-Oxygen Donor Ligands

    Science.gov (United States)

    Seitz, Michael; Do, King; Ingram, Andrew J.; Moore, Evan G.; Muller, Gilles; Raymond, Kenneth N.

    2009-01-01

    Abstract: Circulaly polarized luminescence from terbium(III) complexed and excited by chiral antenna ligands gives strong emission The modular synthesis of three new octadentate, enantiopure ligands are reported - one with the bidentate chelating unit 2-hydroxyisophthalamide (IAM) and two with 1-hydroxy-2-pyridinone (1,2-HOPO) units. A new design principle is introduced for the chiral, non-racemic hexamines which constitute the central backbones for the presented class of ligands. The terbium(III) complex of the IAM ligand, as well as the europium(III) complexes of the 1,2-HOPO ligands are synthesized and characterized by various techniques (NMR, UV, CD, luminescence spectroscopy). All species exhibit excellent stability and moderate to high luminescence efficiency (quantum yields ΦEu = 0.05–0.08 and ΦTb = 0.30–0.57) in aqueous solution at physiological pH. Special focus is put onto the properties of the complexes in regard to circularly polarized luminescence (CPL). The maximum luminescence dissymmetry factors (glum) in aqueous solution are high with |glum|max = 0.08 – 0.40. Together with the very favorable general properties (good stability, high quantum yields, long lifetimes), the presented lanthanide complexes can be considered as good candidates for analytical probes based on CPL in biologically relevant environments. PMID:19639983

  10. Complexation and molecular modeling studies of europium(III)-gallic acid-amino acid complexes.

    Science.gov (United States)

    Taha, Mohamed; Khan, Imran; Coutinho, João A P

    2016-04-01

    With many metal-based drugs extensively used today in the treatment of cancer, attention has focused on the development of new coordination compounds with antitumor activity with europium(III) complexes recently introduced as novel anticancer drugs. The aim of this work is to design new Eu(III) complexes with gallic acid, an antioxida'nt phenolic compound. Gallic acid was chosen because it shows anticancer activity without harming health cells. As antioxidant, it helps to protect human cells against oxidative damage that implicated in DNA damage, cancer, and accelerated cell aging. In this work, the formation of binary and ternary complexes of Eu(III) with gallic acid, primary ligand, and amino acids alanine, leucine, isoleucine, and tryptophan was studied by glass electrode potentiometry in aqueous solution containing 0.1M NaNO3 at (298.2 ± 0.1) K. Their overall stability constants were evaluated and the concentration distributions of the complex species in solution were calculated. The protonation constants of gallic acid and amino acids were also determined at our experimental conditions and compared with those predicted by using conductor-like screening model for realistic solvation (COSMO-RS) model. The geometries of Eu(III)-gallic acid complexes were characterized by the density functional theory (DFT). The spectroscopic UV-visible and photoluminescence measurements are carried out to confirm the formation of Eu(III)-gallic acid complexes in aqueous solutions. Copyright © 2016 Elsevier Inc. All rights reserved.

  11. Luminescent single-walled carbon nanotube-sensitized europium nanoprobes for cellular imaging

    Science.gov (United States)

    Avti, Pramod K; Sitharaman, Balaji

    2012-01-01

    Lanthanoid-based optical probes with excitation wavelengths in the ultra-violet (UV) range (300–325 nm) have been widely developed as imaging probes. Efficient cellular imaging requires that lanthanoid optical probes be excited at visible wavelengths, to avoid UV damage to cells. The efficacy of europium-catalyzed single-walled carbon nanotubes (Eu-SWCNTs), as visible nanoprobes for cellular imaging, is reported in this study. Confocal fluorescence microscopy images of breast cancer cells (SK-BR-3 and MCF-7) and normal cells (NIH 3T3), treated with Eu-SWCNT at 0.2 μg/mL concentration, showed bright red luminescence after excitation at 365 nm and 458 nm wavelengths. Cell viability analysis showed no cytotoxic effects after the incubation of cells with Eu-SWCNTs at this concentration. Eu-SWCNT uptake is via the endocytosis mechanism. Labeling efficiency, defined as the percentage of incubated cells that uptake Eu-SWCNT, was 95%–100% for all cell types. The average cellular uptake concentration was 6.68 ng Eu per cell. Intracellular localization was further corroborated by transmission electron microscopy and Raman microscopy. The results indicate that Eu-SWCNT shows potential as a novel cellular imaging probe, wherein SWCNT sensitizes Eu3+ ions to allow excitation at visible wavelengths, and stable time-resolved red emission. The ability to functionalize biomolecules on the exterior surface of Eu-SWCNT makes it an excellent candidate for targeted cellular imaging. PMID:22619533

  12. Europium(III) DOTA-derivatives having ketone donor pendant arms display dramatically slower water exchange

    Science.gov (United States)

    Green, Kayla N.; Viswanathan, Subha; Rojas-Quijano, Federico A.; Kovacs, Zoltan; Sherry, A. Dean

    2011-01-01

    A series of new 1,4,7,10-tetraazacyclododecane-derivatives having a combination of amide and ketone donor groups as side-arms were prepared and their complexes with europium(III) studied in detail by high resolution NMR spectroscopy. The chemical shift of the Eu3+-bound water resonance, the chemical exchange saturation transfer (CEST) characteristics of the complexes, and the bound water residence lifetimes (τm) were found to vary dramatically with the chemical structure of the side-arms. Substitution of ketone oxygen donor atoms for amide oxygen donor atoms resulted in an increase in residence water lifetimes (τm) and a decrease in chemical shift of the Eu3+-bound water molecule (Δω). These experimental results along with density functional theory (DFT) calculations demonstrate that introduction of weakly donating oxygen atoms in these complexes results in a much weaker ligand field, more positive charge on the Eu3+ ion and an increased water residence lifetime as expected for a dissociative mechanism. These results provide new insights into the design of paramagnetic CEST agents with even slower water exchange kinetics that will make them more efficient for in vivo imaging applications. PMID:21306137

  13. Urinary monitoring of exposure to yttrium, scandium, and europium in male Wistar rats.

    Science.gov (United States)

    Kitamura, Yasuhiro; Usuda, Kan; Shimizu, Hiroyasu; Fujimoto, Keiichi; Kono, Rei; Fujita, Aiko; Kono, Koichi

    2012-12-01

    On the assumption that rare earth elements (REEs) are nontoxic, they are being utilized as replacements of toxic heavy metals in novel technological applications. However, REEs are not entirely innocuous, and their impact on health is still uncertain. In the past decade, our laboratory has studied the urinary excretion of REEs in male Wistar rats given chlorides of europium, scandium, and yttrium solutions by one-shot intraperitoneal injection or oral dose. The present paper describes three experiments for the suitability and appropriateness of a method to use urine for biological monitoring of exposure to these REEs. The concentrations of REEs were determined in cumulative urine samples taken at 0-24 h by inductively coupled plasma atomic emission spectroscopy, showing that the urinary excretion of REEs is <2 %. Rare earth elements form colloidal conjugates in the bloodstream, which make high REEs accumulation in the reticuloendothelial system and glomeruli and low urinary excretion. The high sensitivity of inductively coupled plasma-argon emission spectrometry analytical methods, with detection limits of <2 μg/L, makes urine a comprehensive assessment tool that reflects REE exposure. The analytical method and animal experimental model described in this study will be of great importance and encourage further discussion for future studies.

  14. Europium Luminescence: Electronic Densities and Superdelocalizabilities for a Unique Adjustment of Theoretical Intensity Parameters

    Science.gov (United States)

    Dutra, José Diogo L.; Lima, Nathalia B. D.; Freire, Ricardo O.; Simas, Alfredo M.

    2015-09-01

    We advance the concept that the charge factors of the simple overlap model and the polarizabilities of Judd-Ofelt theory for the luminescence of europium complexes can be effectively and uniquely modeled by perturbation theory on the semiempirical electronic wave function of the complex. With only three adjustable constants, we introduce expressions that relate: (i) the charge factors to electronic densities, and (ii) the polarizabilities to superdelocalizabilities that we derived specifically for this purpose. The three constants are then adjusted iteratively until the calculated intensity parameters, corresponding to the 5D0→7F2 and 5D0→7F4 transitions, converge to the experimentally determined ones. This adjustment yields a single unique set of only three constants per complex and semiempirical model used. From these constants, we then define a binary outcome acceptance attribute for the adjustment, and show that when the adjustment is acceptable, the predicted geometry is, in average, closer to the experimental one. An important consequence is that the terms of the intensity parameters related to dynamic coupling and electric dipole mechanisms will be unique. Hence, the important energy transfer rates will also be unique, leading to a single predicted intensity parameter for the 5D0→7F6 transition.

  15. Structural and spectroscopic analyses of europium doped yttrium oxyfluoride powders prepared by combustion synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Rakov, Nikifor [PG-Ciência dos Materiais, Universidade Federal do Vale do São Francisco, 48902-300 Juazeiro, BA (Brazil); Guimarães, R. B.; Maciel, Glauco S. [Instituto de Física, Universidade Federal Fluminense, 24210-346 Niterói, RJ (Brazil); Lozano B, W. [Departamento de Física, Universidade Federal de Pernambuco, 50670-901 Recife, PE (Brazil)

    2013-07-28

    A facile widely spread technique employed to produce low-cost high-yield oxide powders, combustion synthesis, was used to prepare yttrium oxyfluoride crystalline ceramic powders. The structure of the powders was analyzed by X-ray powder diffraction and Rietveld refinement. Samples heat treated at 700 °C had a predominance of vernier orthorhombic Y{sub 6}O{sub 5}F{sub 8} phase, while samples heat treated at 800 °C crystallized in stoichiometric rhombohedral YOF phase. The samples were doped with luminescent europium trivalent ions (Eu{sup 3+}) in different concentrations (1–15 wt.%) and Judd-Ofelt theory was used to probe the distortion from the inversion symmetry of the local crystal field and the degree of covalency between the rare-earth ion and the surrounding ligands. The luminescence lifetime was measured and the luminescence quantum efficiency (LQE) was estimated. We observed that Eu{sup 3+}:Y{sub 6}O{sub 5}F{sub 8} samples presented higher LQE in spite of the larger local crystal field anisotropy found for Eu{sup 3+}:YOF samples.

  16. COMPARISON OF SOL-GEL SILICATE COATINGS ON Ti SUBSTRATE

    Directory of Open Access Journals (Sweden)

    DIANA HORKAVCOVÁ

    2012-12-01

    Full Text Available The objective of the submitted work was to prepare and to characterize two types of silicate coatings prepared by the sol-gel method using the dip-coating technique on a titanium substrate. Efforts have been made to use mechanical properties of bio-inert titanium and bioactive properties of a silicate layer enriched with an admixture of compounds identified below. The first group consisted of silicate coatings containing silver, brushite and monetite. The other group of silicate coatings contained calcium nitrate and triethyl phosphate. Mechanically and chemically treated titanium substrates were dipped into sols and dried and fired. Silicate coatings from the first group were also chemically treated in 10 mol.l-1 solution of sodium hydroxide. All coatings were measured to determine their adhesive and bioactive properties and furthermore the antibacterial properties were tested in the case of first group. Surfaces of the coated substrates were investigated after the firing and after the individual tests with optical and electron microscopy and X-ray microdiffraction. A tape test demonstrated excellent adhesive property of all coatings to the substrate, classified with degree 5. A static in vitro test demonstrated bioactivity of nearly all the coatings. The basic silicate coating from the first group and one type of coating from the second group were identified as inert. Antibacterial properties of silicate coatings containing silver showed to be different when tested against Escherichia coli bacteria. A complete inhibition of the growth of bacteria under our experimental conditions was observed for the coating containing silver and monetite and a partial inhibition of the growth of bacteria for coatings containing silver and silver in combination with brushite.

  17. Synthesis, photophysics, electrochemistry, thermal stability and electroluminescent performances of a new europium complex with bis(β-diketone) ligand containing carbazole group.

    Science.gov (United States)

    Liu, Jian; Liang, Quan-Bin; Wu, Hong-Bin

    2017-05-01

    We synthesized a new europium complex [Eu(ecbpd)3 (Phen)] with bis(β-diketone) ligand containing a carbazole group, in which ecbpd and Phen are dehydro-3,3'-(9-ethyl-9H-carbazole-3,6-diyl)bis(1-phenylpropane-1,3-dione) and 1,10-phenanthroline, respectively. Its UV/vis and photoluminescent spectra, quantum yield, luminescence lifetime, electrochemistry, thermal stability and electroluminescent performances were studied. This europium complex showed low efficiency luminescence, which is probably due to the mismatching energy levels of its ligand and Eu3+ , as well as the double Eu3+ core resonance. Copyright © 2016 John Wiley & Sons, Ltd.

  18. SON68 glass dissolution driven by magnesium silicate precipitation

    Energy Technology Data Exchange (ETDEWEB)

    Fleury, Benjamin, E-mail: benjamin.fleury@cea.fr [CEA Marcoule, DEN/DTCD/SECM/LCLT, BP17171, 30207 Bagnols-sur-cèze (France); Godon, Nicole [CEA Marcoule, DEN/DTCD/SECM/LCLT, BP17171, 30207 Bagnols-sur-cèze (France); Ayral, André [IEM, University Montpellier 2, CC 047, Place Eugène Bataillon, 34095 Montpellier Cedex 5 (France); Gin, Stéphane [CEA Marcoule, DEN/DTCD/SECM/LCLT, BP17171, 30207 Bagnols-sur-cèze (France)

    2013-11-15

    Experimental results are reported on the effect of magnesium silicate precipitation on the mechanisms and rate of borosilicate glass dissolution. Leaching experiments with SON68 glass, a borosilicate containing no Mg, were carried out in initially deionized water at 50 °C with a glass-surface-area-to-solution-volume ratio of 20,000 m{sup −1}. After 29 days of alteration the experimental conditions were modified by the addition of Mg to trigger the precipitation of Mg-silicate. Additional experiments were conducted to investigate the importance of other parameters such as pH or dissolved silica on the mechanisms of precipitation of Mg-silicates and their consequences on the glass dissolution rate. Mg-silicates precipitate immediately after Mg is added. The amount of altered glass increases with the quantity of added Mg, and is smaller when silicon is added in solution. A time lag is observed between the addition of magnesium and the resumption of glass alteration because silicon is first provided by partial dissolution of the previously formed alteration gel. It is shown that nucleation does not limit Mg-silicate precipitation. A pH above 8 is necessary for the phase to precipitate under the investigated experimental conditions. On the other hand the glass alteration kinetics limits the precipitation if the magnesium is supplied in solution at a non-limiting rate.

  19. Heterogeneous nucleation of protein crystals on fluorinated layered silicate.

    Directory of Open Access Journals (Sweden)

    Keita Ino

    Full Text Available Here, we describe an improved system for protein crystallization based on heterogeneous nucleation using fluorinated layered silicate. In addition, we also investigated the mechanism of nucleation on the silicate surface. Crystallization of lysozyme using silicates with different chemical compositions indicated that fluorosilicates promoted nucleation whereas the silicates without fluorine did not. The use of synthesized saponites for lysozyme crystallization confirmed that the substitution of hydroxyl groups contained in the lamellae structure for fluorine atoms is responsible for the nucleation-inducing property of the nucleant. Crystallization of twelve proteins with a wide range of pI values revealed that the nucleation promoting effect of the saponites tended to increase with increased substitution rate. Furthermore, the saponite with the highest fluorine content promoted nucleation in all the test proteins regardless of their overall net charge. Adsorption experiments of proteins on the saponites confirmed that the density of adsorbed molecules increased according to the substitution rate, thereby explaining the heterogeneous nucleation on the silicate surface.

  20. Silicate fertilizer and irrigation depth in corn production

    Directory of Open Access Journals (Sweden)

    Edvaldo Eloy Dantas Júnior

    2013-08-01

    Full Text Available Calcium-magnesium silicates improve the soil physicochemical properties and provide benefits to plant nutrition, since they are sources of silica, calcium and magnesium. The objective of this study was to evaluate the grain yield of irrigated corn fertilized with calcium-magnesium silicate. The experiment was carried out in a greenhouse in Campina Grande - PB, Brazil, using plastic pots containing 80 kg of soil. The treatments consisted of the combination of four irrigation depths, related to water replacement of 50, 75, 100 and 125% of the crop evapotranspiration, with fertilizer levels of 0, 82, 164 and 246 g of calcium-magnesium silicate, with three replications. The experimental design was in randomized blocks, with the irrigation depths distributed in bands while the silicon levels constituted the subplots. Corn yield was influenced by calcium-magnesium silicate and by irrigation depth, obtaining the greatest grain yield with the dose of 164 g pot-1 irrigated at the highest water level. The water-use efficiency of in corn production tended to decrease when the irrigation depth was increased. The best water-use efficiency was observed when the irrigation level was between 87 and 174 mm, and the dose of silicate was 164 g pot-1.

  1. Europium (III) PVC membrane sensor based on N-pyridine-2-carboxamido-8-aminoquinoline as a sensing material

    Energy Technology Data Exchange (ETDEWEB)

    Zamani, Hassan Ali, E-mail: haszamani@yahoo.com [Department of Applied Chemistry, Quchan branch, Islamic Azad University, Quchan (Iran, Islamic Republic of); Kamjoo, Rahman [Department of Applied Chemistry, Quchan branch, Islamic Azad University, Quchan (Iran, Islamic Republic of); Mohammadhosseini, Majid [Department of Chemistry, Faculty of Basic Sciences, Shahrood Branch, Islamic Azad University, Shahrood (Iran, Islamic Republic of); Zaferoni, Mojdeh; Rafati, Zynab [Department of Applied Chemistry, Quchan branch, Islamic Azad University, Quchan (Iran, Islamic Republic of); Ganjali, Mohammad Reza [Center of Excellence in Electrochemistry, Faculty of Chemistry, University of Tehran, Tehran (Iran, Islamic Republic of); Endocrinology and Metabolism Research Center, Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Faridbod, Farnoush [Endocrinology and Metabolism Research Center, Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Meghdadi, Soraia [Department of Chemistry, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of)

    2012-04-01

    Conductometric study in acetonitrile solution shows the selectivity of PCQ toward europium ion. Therefore, a new europium PVC membrane electrode was prepared based on N-pyridine-2-carboxamido-8-aminoquinoline (PCQ) as an ion carrier. The electrode has a wide concentration range from 1.0 Multiplication-Sign 10{sup -2} and 1.0 Multiplication-Sign 10{sup -6} mol L{sup -1}, Nernstian slope of 19.8 {+-} 0.3 mV per decade and a detection limit of 6.4 Multiplication-Sign 10{sup -7} mol L{sup -1}. The potentiometric response is pH independent in the range of 2.4-7.4. The proposed sensor has a relatively fast response time less than 10 s and it can be used for at least 2 months without any considerable divergence in its potentials. The proposed electrode revealed good selectivity toward europium ion in comparison with variety of other metal ions. The practical utility of the electrodes has been demonstrated by their use as indicator electrodes in the potentiometric titration of Eu{sup 3+} ions with EDTA and for determination of Eu{sup 3+} ion concentration in mixtures of two and three different ions. - Highlights: Black-Right-Pointing-Pointer A new ion carrier is introduced to preparation of a selective sensor for Eu{sup 3+} ions. Black-Right-Pointing-Pointer This technique is very simple and it's not necessary to use sophisticated equipment. Black-Right-Pointing-Pointer The novelty of this work is the high affinity of the ionophore toward the Eu{sup 3+} ions. Black-Right-Pointing-Pointer The sensor is superior to the formerly reported Eu{sup 3+} sensors in terms of selectivity.

  2. A novel tridentate bis(phosphinic acid)phosphine oxide based europium(III)-selective Nafion membrane luminescent sensor.

    Science.gov (United States)

    Sainz-Gonzalo, F J; Popovici, C; Casimiro, M; Raya-Barón, A; López-Ortiz, F; Fernández, I; Fernández-Sánchez, J F; Fernández-Gutiérrez, A

    2013-10-21

    A new europium(III) membrane luminescent sensor based on a new tridentate bis(phosphinic acid)phosphine oxide (3) system has been developed. The synthesis of this new ligand is described and its full characterization by NMR, IR and elemental analyses is provided. The luminescent complex formed between europium(III) chloride and ligand 3 was evaluated in solution, observing that its spectroscopic and chemical characteristics are excellent for measuring in polymer inclusion membranes. Included in a Nafion membrane, all the parameters (ligand and ionic additives) that can affect the sensitivity and selectivity of the sensing membrane as well as the instrumental conditions were carefully optimized. The best luminescence signal (λexc = 229.06 nm and λem = 616.02 nm) was exhibited by the sensing film having a Nafion : ligand composition of 262.3 : 0.6 mg mL(-1). The membrane sensor showed a short response time (t95 = 5.0 ± 0.2 min) and an optimum working pH of 5.0 (25 mM acetate buffer solution). The membrane sensor manifested a good selectivity toward europium(III) ions with respect to other trivalent metals (iron, chromium and aluminium) and lanthanide(III) ions (lanthanum, samarium, terbium and ytterbium), although a small positive interference of terbium(III) ions was observed. It provided a linear range from 1.9 × 10(-8) to 5.0 × 10(-6) M with a very low detection limit (5.8 × 10(-9) M) and sensitivity (8.57 × 10(-7) a.u. per M). The applicability of this sensing film has been demonstrated by analyzing different kinds of spiked water samples obtaining recovery percentages of 95-97%.

  3. A Responsive Europium(III) Chelate that Provides a Direct Readout of pH by MRI

    Science.gov (United States)

    Wu, Yunkou; Soesbe, Todd C.; Kiefer, Garry E.; Zhao, Piyu; Sherry, A. Dean

    2010-01-01

    A europium(III) DO3A-tris(amide) complex is reported for imaging pH by MRI using ratiometric CEST principles. Deprotonation of a single phenolic proton between pH 6 and 7.6 results in an ~5 ppm shift in the water exchange CEST peak that is easily detected by MRI. Collection of two CEST images at two slightly different activation frequencies provides a direct readout of solution pH without the need of a concentration marker. PMID:20853833

  4. Steam based conversion coating on AA6060 alloy: Effect of sodium silicate chemistry and corrosion performance

    Science.gov (United States)

    Din, Rameez Ud; Bordo, Kirill; Tabrizian, Naja; Jellesen, Morten Stendahl; Ambat, Rajan

    2017-11-01

    Surface treatment of aluminium alloy AA6060 using an industrially applicable pilot steam jet system with and without silicate chemistry has been investigated. Treatment using steam alone and steam with silicate, resulted in an oxide layer formation with thickness ∼425 nm and ∼160 nm, respectively. Moreover, the use of sodium silicate resulted in the formation of distinct microstructure and incorporation of silicate into the oxide film. These oxide films reduced the anodic activity 4 times, while the corrosion protection by silicate containing oxide was the function of its concentration. Further, in acid salt spray and filiform corrosion tests, oxide layer containing silicate exhibited two times higher corrosion resistance.

  5. Copper Containing Silicates as Catalysts for Liquid Phase Cyclohexane Oxidation

    Directory of Open Access Journals (Sweden)

    Cruz Rosenira S. da

    2002-01-01

    Full Text Available Copper containing silicates have been prepared by an acid-catalyzed sol-gel process. The materials were characterized by X-ray diffraction and fluorescence, EPR spectroscopy, elemental analysis, N2-physisorption, thermogravimetry, differential scanning calorimetry, temperature-programmed reduction, FTIR and UV/VIS spectroscopy. The silicates were shown to be efficient catalysts for the oxidation of cyclohexane with tert-butyl hydroperoxide as oxidant. Cyclohexanol and cyclohexanone were obtained as the main products. The metal was shown to be weakly bound to the silicate matrix and metal leaching was observed. Leaching was quantified by X-ray fluorescence and leaching tests showed that the catalytic activity is due to supported copper species. Leached copper showed no activity in the homogeneous phase.

  6. Rubber curing chemistry governing the orientation of layered silicate

    Directory of Open Access Journals (Sweden)

    2007-11-01

    Full Text Available The effect of curing systems on the orientation and the dispersion of the layered silicates in acrylonitrile butadiene rubber nanocomposite is reported. Significant differences in X-ray diffraction pattern between peroxide curing and sulfur curing was observed. Intense X-ray scattering values in the XRD experiments from peroxide cured vulcanizates indicate an orientation of the layers in a preferred direction as evinced by transmission electron micrographs. However, sulfur cured vulcanizates show no preferential orientation of the silicate particles. Nevertheless, a closer inspection of transmission electron microscopy (TEM images of peroxide and sulfur cured samples shows exfoliated silicate layers in the acrylonitrile butadiene rubber (NBR matrix. It was revealed in the prevailing study that the use of an excess amount of stearic acid in the formulation of the sulfur curing package leads to almost exfoliated type X-ray scattering pattern.

  7. Petrophysical Analysis of Siliceous Ooze Sediments, Ormen Lange Field, Norway

    DEFF Research Database (Denmark)

    Awedalkarim, Ahmed; Fabricius, Ida Lykke

    structure is complex and the solids are mechanically fragile and hydrous. Normal petrophysical methods used in formation evaluation might not be suitable for interpreting siliceous ooze. For example, density and neutron logging tools are calibrated to give correct porosity readings in a limestone formation...... to analyse and interpret logging data acquired through siliceous ooze sediments. Our main objectives were to characterize and evaluate the petrophysics of siliceous ooze and to find the true porosity and water saturation to test its hydrocarbon reservoir potential. We used and integrated core analysis data...... with logging data from four Ormen Lange wells, and included X-ray diffraction analysis (XRD) data. Additionally, other available information such as petrographic thin-section analysis, core computed tomography scans (CT-scans), scanning electron microscope (SEM), and other published data were used here...

  8. Potential of calcium silicate to mitigate water deficiency in maize

    Directory of Open Access Journals (Sweden)

    Douglas José Marques

    2016-01-01

    Full Text Available ABSTRACT The aim of this study was to evaluate the potential of calcium silicate to mitigate the effects of water deficiency in maize plants yield. A completely randomized factorial design, consisting of five combinations of calcium silicate (0, 25, 50, 75, and 100% and five different soil moisture levels (30, 70, 100, 130, and 160%, was adopted. The following parameters were evaluated: soil matric potential, xylem water potential, silicon concentration, leaf dry weight, and dry mass production. Matric potential monitoring confirmed that the irrigation depths employed resulted in different environments for maize plant development during the experiment. Confirming the hypothesis of the study, at the lower irrigation depths, the maize production has accompanied the increase in calcium silicate used as corrective up to the proportion of 50%. These results indicate that silicon mitigated the impact of water deficiency in maize plants and increased the xylem water potential.

  9. Energetic Processing of Interstellar Silicate Grains by Cosmic Rays

    Energy Technology Data Exchange (ETDEWEB)

    Bringa, E M; Kucheyev, S O; Loeffler, M J; Baragiola, R A; Tielens, A G Q M; Dai, Z R; Graham, G; Bajt, S; Bradley, J; Dukes, C A; Felter, T E; Torres, D F; van Breugel, W

    2007-03-28

    While a significant fraction of silicate dust in stellar winds has a crystalline structure, in the interstellar medium nearly all of it is amorphous. One possible explanation for this observation is the amorphization of crystalline silicates by relatively 'low' energy, heavy ion cosmic rays. Here we present the results of multiple laboratory experiments showing that single-crystal synthetic forsterite (Mg{sub 2}SiO{sub 4}) amorphizes when irradiated by 10 MeV Xe{sup ++} ions at large enough fluences. Using modeling, we extrapolate these results to show that 0.1-5.0 GeV heavy ion cosmic rays can rapidly ({approx}70 Million yrs) amorphize crystalline silicate grains ejected by stars into the interstellar medium.

  10. Potassium Silicate Foliar Fertilizer Grade from Geothermal Sludge and Pyrophyllite

    Directory of Open Access Journals (Sweden)

    Muljani Srie

    2016-01-01

    Full Text Available Potassium silicate fertilizer grade were successfully produced by direct fusion of silica (SiO2 and potasium (KOH and K2CO3 in furnaces at temperatures up to melting point of mixture. The geothermal sludge (98% SiO2 and the pyrophyllite (95% SiO2 were used as silica sources. The purposes of the study was to synthesise potassium silicate fertilizer grade having solids concentrations in the range of 31-37% K2O, and silica in the range of 48-54% SiO2. The weight ratio of silicon dioxide/potasium solid being 1:1 to 5:1. Silica from geothermal sludge is amorphous, whereas pyrophylite is crystalline phase. The results showed that the amount of raw materials needed to get the appropriate molar ratio of potassium silicate fertilizer grade are different, as well as the fusion temperature of the furnace. Potassium silicate prepared from potassium hydroxide and geothermal sludge produced a low molar ratio (2.5: 1 to 3: 1. The potassium required quite small (4:1 in weight ratio, and on a fusion temperature of about 900 °C. Meanwhile, the potassium silicate prepared from pyrophyllite produced a high molar ratio (1.4 - 9.4 and on a fusion temperature of about 1350 °C, so that potassium needed large enough to meet the required molar ratio for the fertilizer grade. The product potassium silicate solid is amorphous with a little trace of crystalline.

  11. Spectroscopic properties and luminescence behaviour of europium doped lithium borate glasses

    Energy Technology Data Exchange (ETDEWEB)

    Anjaiah, J., E-mail: anjaiah.juluru@gmail.com [Department of Physics, The University of Dodoma, Tanzania, East Africa (Tanzania, United Republic of); Department of Physics, Geethanjali College of Engineering and Technology, Keesara, RR Dist., Hyderabad 501 301 (India); Laxmikanth, C. [Department of Physics, The University of Dodoma, Tanzania, East Africa (Tanzania, United Republic of); Veeraiah, N. [Department of Physics, Acharya Nagarjuna University, Nagarjuna Nagar, Guntur 522 510, AP. (India)

    2014-12-01

    Li{sub 2}O–MO–B{sub 2}O{sub 3} (MO=ZnO, CaO and CdO) glasses doped with europium are prepared by using the melt quenching technique to study their absorption and luminescence properties to understand their lasing potentialities. The XRD pattern of the glasses confirmed the amorphous nature and the IR spectra reveal the presence of BO{sub 3} and BO{sub 4} units in the glass network. Judd–Ofelt intensity parameters Ω{sub λ} (λ=2, 4, 6) are evaluated from the intensities of various absorption bands of optical absorption spectra. The J–O parameters have been used to calculate transition probabilities (A), lifetime (τ{sub R}), branching ratios (β{sub R}) and stimulated emission cross-section (σ{sub P}) for the {sup 5}D{sub 0}→{sup 7}F{sub J} (J=1–4) transitions of the Eu{sup 3+} ions. The decay from the {sup 5}D{sub 0} level of Eu{sup 3+} ions in these glasses has been measured and analysed. Branching ratios and stimulated emission cross-sections measured for all these glasses show that the {sup 5}D{sub 0}→{sup 7}F{sub 1} transition under investigation has the potential for laser applications. The high stimulated emission cross-section and branching ratios from the present glasses suggests their potential for infra red lasers. The study of the thermoluminescence is also carried out and the data suggests that the CdBEu glass is suitable for thermoluminescence emission output among the three Eu{sup 3+} doped glasses.

  12. Size-dependent cytotoxicity of europium doped NaYF{sub 4} nanoparticles in endothelial cells

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Shizhu; Zhang, Cuimiao; Jia, Guang; Duan, Jianlei; Wang, Shuxiang, E-mail: wsx@hbu.edu.cn; Zhang, Jinchao, E-mail: jczhang6970@163.com

    2014-10-01

    Lanthanide-doped sodium yttrium fluoride (NaYF{sub 4}) nanoparticles exhibit novel optical properties which make them be widely used in various fields. The extensive applications increase the chance of human exposure to these nanoparticles and thus raise deep concerns regarding their riskiness. In the present study, we have synthesized europium doped NaYF{sub 4} (NaYF{sub 4}:Eu{sup 3+}) nanoparticles with three diameters and used endothelial cells (ECs) as a cell model to explore the potential toxic effect. The cell viability, cytomembrane integrity, cellular uptake, intracellular localization, intracellular reactive oxygen species (ROS), mitochondrial membrane potential (MMP), apoptosis detection, caspase-3 activity and expression of inflammatory gene were studied. The results indicated that these nanoparticles could be uptaken into ECs and decrease the cell viability, induce the intracellular lactate dehydrogenase (LDH) release, increase the ROS level, and decrease the cell MMP in a size-dependent manner. Besides that, the cells were suffered to apoptosis with the caspase-3 activation, and the inflammation specific gene expressions (ICAM1 and VCAM1) were also increased. Our results suggest that the damage pathway may be related to the ROS generation and mitochondrial damage. The results provide novel evidence to elucidate their toxicity mechanisms and may be helpful for more rational applications of these compounds in the future. - Highlights: • NaYF{sub 4}:Eu{sup 3+} nanoparticles with three diameters have been synthesized. • NaYF{sub 4}:Eu{sup 3+} nanoparticles could be uptaken by endothelial cells (ECs). • NaYF{sub 4}:Eu{sup 3+} nanoparticles show a significant cytotoxicity on ECs. • The size of NaYF{sub 4}:Eu{sup 3+} nanoparticles may be important to their toxicology effect.

  13. Two-dimensional high spatial-resolution dosimeter using europium doped potassium chloride: a feasibility study

    Science.gov (United States)

    Li, H. Harold; Driewer, Joseph P.; Han, Zhaohui; Low, Daniel A.; Yang, Deshan; Xiao, Zhiyan

    2014-01-01

    Recent research has shown that KCl:Eu2+ has great potential for use in megavoltage radiation therapy dosimetry because this material exhibits excellent storage performance and is reusable due to strong radiation hardness. This work reports the authors’ attempts to fabricate 2D KCl:Eu2+ storage phosphor films (SPFs) using both a physical vapor deposition (PVD) method and a tape casting method. X ray diffraction analysis showed that a 10 µm thick PVD sample was composed of highly crystalline KCl. No additional phases were observed, suggesting that the europium activator had completed been incorporated into the KCl matrix. Photostimulated luminescence and photoluminescence spectra suggested that F (Cl-) centers were the electron storage centers post×ray irradiation and that Eu2+ cations acted as luminescence centers in the photostimulation process. The 150-µm thick casted KCl:Eu2+ SPF showed sub-millimeter spatial resolution. Monte Carlo simulations further demonstrated that the admixture of 20% KCl:Eu2+ and 80% low Z polymer binder exhibited almost no energy dependence in a 6 MV beam. KCl:Eu2+ pellet samples showed a large dynamic range from 0.01 cGy to 60 Gy dose-to-water, and saturated at approximately 500 Gy as a result of KCl’s intrinsic high radiation hardness. Taken together, this work provides strong evidence that KCl:Eu2+ based SPF with associated readout apparatus could result in a novel electronic film system that has all the desirable features associated with classic radiographic film and, importantly, water equivalence and the capability of permanent identification of each detector. PMID:24651448

  14. A Novel Europium Chelate Coated Nanosphere for Time-Resolved Fluorescence Immunoassay

    Science.gov (United States)

    Shen, Yifeng; Xu, Shaohan; He, Donghua

    2015-01-01

    A novel europium ligand 2, 2’, 2’’, 2’’’-(4, 7-diphenyl-1, 10-phenanthroline-2, 9-diyl) bis (methylene) bis (azanetriyl) tetra acetic acid (BC-EDTA) was synthesized and characterized. It shows an emission spectrum peak at 610 nm when it is excited at 360 nm, with a large Stock shift (250 nm). It is covalently coated on the surface of a bare silica nanosphere containi free amino groups, using 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride and N-Hydroxysuccinimide. We also observed an interesting phenomenon that when BC-EDTA is labeled with a silica nanosphere, the chelate shows different excitation spectrum peaks of about 295 nm. We speculate that the carboxyl has a significant influence on its excitation spectrum. The BC-EDTA/Eu3+coated nanosphere could be used as a fluorescent probe for time-resolved fluorescence immunoassay. We labeled the antibody with the fluorescent nanosphere to develop a nanosphere based hepatitis B surface antigen as a time-resolved fluorescence immunoassay reagent, which is very easy to operate and eliminates potential contamination of Eu3+ contained in the environment. The analytical and functional sensitivities are 0.0037 μg/L and 0.08 μg/L (S/N≥2.0) respectively. The detection range is 0.08-166.67 μg/L, which is much wider than that of ELISA (0.2-5μg/L). It is comparable to the commercial dissociation-enhanced lanthanide fluoro-immunoassay system (DELFIA) reagents (0.2-145μg/L). We propose that it can fulfill clinical applications. PMID:26056826

  15. A Novel Europium Chelate Coated Nanosphere for Time-Resolved Fluorescence Immunoassay.

    Directory of Open Access Journals (Sweden)

    Yifeng Shen

    Full Text Available A novel europium ligand 2,2',2'',2'''-(4,7-diphenyl-1,10-phenanthroline-2,9-diyl bis (methylene bis (azanetriyl tetra acetic acid (BC-EDTA was synthesized and characterized. It shows an emission spectrum peak at 610 nm when it is excited at 360 nm, with a large Stock shift (250 nm. It is covalently coated on the surface of a bare silica nanosphere containi free amino groups, using 1-ethyl-3-(3-dimethylaminopropyl carbodiimide hydrochloride and N-Hydroxysuccinimide. We also observed an interesting phenomenon that when BC-EDTA is labeled with a silica nanosphere, the chelate shows different excitation spectrum peaks of about 295 nm. We speculate that the carboxyl has a significant influence on its excitation spectrum. The BC-EDTA/Eu3+coated nanosphere could be used as a fluorescent probe for time-resolved fluorescence immunoassay. We labeled the antibody with the fluorescent nanosphere to develop a nanosphere based hepatitis B surface antigen as a time-resolved fluorescence immunoassay reagent, which is very easy to operate and eliminates potential contamination of Eu3+ contained in the environment. The analytical and functional sensitivities are 0.0037 μg/L and 0.08 μg/L (S/N≥2.0 respectively. The detection range is 0.08-166.67 μg/L, which is much wider than that of ELISA (0.2-5 μg/L. It is comparable to the commercial dissociation-enhanced lanthanide fluoro-immunoassay system (DELFIA reagents (0.2-145 μg/L. We propose that it can fulfill clinical applications.

  16. Thermoluminescence of europium-doped zinc oxide exposed to beta particle irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Iriqui R, J. L.; Cruz V, C. [Universidad de Sonora, Departamento de Investigacion en Polimeros y Materiales, Apdo. Postal 130, 83000 Hermosillo, Sonora (Mexico); Bernal, R. [Universidad de Sonora, Departamento de Investigacion en Fisica, Apdo. Postal 5-088, 83000 Hermosillo, Sonora (Mexico); Castano, V. M., E-mail: jorgeiriqui@gimmunison.com [UNAM, Instituto de Fisica, Centro de Fisica Aplicada y Tecnologia Avanzada, Apdo. Postal 1-1010, 76000 Queretaro, Qro. (Mexico)

    2015-10-15

    Full text: Zn O is a promising material for a range of optoelectronics applications, due to its direct wide band gap (E{sub g} ∼3.3 eV at 300 K) and large exciton binding energy (60 MeV). Its applications include UV light emitters, varistors, surface acoustic wave devices, piezoelectric transducers, and chemical and gas sensing. Rare-earth activation of phosphors has long been seen as an effective process since coupling energy into the rare-earth-ion site, either by ionization, charge exchange or a resonance energy process, results in light production. It is reported that Europium modifies the response thermoluminescence (Tl) for pure zinc oxide, when is irradiated with X-ray, created a peak at 365 degrees C. In this work, Zn O:Eu phosphors were synthesized by a chemical method. Some samples were exposed to beta particle irradiation for doses ranging from 1 up to 100 Gy. Tl response as a function of dose is linear throughout the studied dose range. The glow curve exhibits three maxima, centered at 176, 279 and 340 degrees C. The reusability studies obtained after ten repeated cycles of annealing irradiation readout for the Zn O:Eu shows that the variation in the Tl response is ten percent and tends to stabilization. The results indicate that these new Zn O:Eu phosphors are promising detectors and dosimeters for beta radiation. The structural and morphological characterization was carried out by X-ray diffraction and scanning electron microscopy, respectively. (Author)

  17. Polymer layered silicate nanocomposites: Structure, morphology, and properties

    Science.gov (United States)

    Nawani, Pranav

    Layered silicates are important fillers for improving various mechanical, flame retardant, and barrier properties of polymers, which can be attributed to their sheet-like morphology. Layered silicates can be modified with organic surfactants to render them compatible with polymer matrices. Organically modified silicates (organoclays) having large surface areas are very cost-efficient non-toxic nanofillers effective at very low loads and are readily available. Upon amalgamation of organoclays with polymer matrix nanocomposites, polymer chains can penetrate in between the silicate layers and result in an intercalated structure where the clay stack remains intact but the interlayer spacing is increased. When penetration becomes more severe, disintegration of clay stacks can occur, resulting in an exfoliated structure. It has often been observed that exfoliation is not complete down to the level of isolated silicate layers; rather, the large clay stacks are broken up into shorter stacks termed 'tactoids' together with a few individual silicate layers, resulting in a kind of mixed intercalated-exfoliated structure. Organoclay particles are mostly intercalated, having a preferred orientation with the clay gallery planes being preferentially parallel to the plane of the pressed film. Preferential orientation of organoclays affects the barrier properties of polymer membranes. Additional fillers like carbon black can induce a change in the orientation of organoclays. The effect of carbon black on the orientation of organoclays was elucidated and a relationship between orientation and permeability of air through such membranes was established. We have also investigated the flammability properties of a series of polymer nanocomposites, containing various Transition Metal Ion (TMI) modified organoclays. The improved fire retardation in nanocomposites with TMI-modified organoclays can be attributed to enhanced carbonaceous char formation during combustion, i.e., charring

  18. Leaf application of silicic acid to upland rice and corn

    Directory of Open Access Journals (Sweden)

    Carlos Alexandre Costa Crusciol

    2013-12-01

    Full Text Available This study aimed to evaluate the effect of Si (stabilized silicic acid, Silamol® leaf application on mineral nutrition and yield in upland rice and corn crops. The treatments were the control (without Si and Si foliar split spraying using 2 L ha-1 of the Silamol® commercial product, with 0.8% soluble Si as concentrated stabilized silicic acid. Silicon leaf application increased the concentrations of K, Ca and Si in rice and corn leaves, the number of panicles per m2 of rice and the number of grains per ear of corn; accordingly, the Si leaf application provided a higher grain yield in both crops.

  19. EPR measurement of the effect of glass composition on the oxidation states of europium

    Science.gov (United States)

    Morris, R. V.; Haskin, L. A.

    1974-01-01

    An investigation was conducted concerning the dependence of the concentration ratio of Eu(2+) to Eu(3+) on composition for silicate liquids whose compositional end members are CaAl2Si2O8 and MgSiO3, MG2SiO4, CaMgSi2O6, CaMgSiO4, CaSiO3, or Ca2SiO4. The liquids were quenched to produce glasses. An electron paramagnetic resonance spectrometer was used to determine the concentration ratios of Eu(2+) to Eu(3+) in the glasses.

  20. Synthesis and characterization of barium titanate, doped with europium and neodymium; Sintese e caracterizacao de titanato de bario, dopados com europio e neodimio

    Energy Technology Data Exchange (ETDEWEB)

    Sousa, Fernanda L.C.; Cabral, Alciney M.; Silva, Ademir O.; Oliveiro, Joao B.L., E-mail: nanda_louise@yahoo.com.br [Universidade Federal do Rio Grande do Norte (UFRN), Natal (Brazil). Instituto de Quimica

    2013-07-01

    This work aims at synthesize and characterize mixed oxides in Barium Titanium matrix in doping with Neodymium and Europium analyzing thermogravimetric curves, characteristic bands at infrared region of the polymer complex, which are intermediates to mixed oxides, and identify the formation thereof, and the crystallinity using XRD analysis.

  1. Stability constants of the Europium complexes with the chloride ions; Constantes de estabilidad de los complejos del europio con los iones cloruro

    Energy Technology Data Exchange (ETDEWEB)

    Jimenez R, M.; Solache R, M.; Rojas H, A. [Instituto Nacional de Investigaciones Nucleares, Departamento de Quimica, A.P. 18-1027, C.P. 11801 Mexico D.F. (Mexico)

    2000-07-01

    The stability constants of lanthanides complexes with chloride ions which were determined at the same ionic force but in different media, are significantly different. It does not exist a systematic study over these stability constants. The purpose of this work is to determine the stability constants of the europium complexes with chloride ions at 303 K, by the solvents extraction method. (Author)

  2. LA-ICP-MS Allows Quantitative Microscopy of Europium-Doped Iron Oxide Nanoparticles and is a Possible Alternative to Ambiguous Prussian Blue Iron Staining.

    Science.gov (United States)

    Scharlach, Constantin; Müller, Larissa; Wagner, Susanne; Kobayashi, Yuske; Kratz, Harald; Ebert, Monika; Jakubowski, Norbert; Schellenberger, Eyk

    2016-05-01

    The development of iron oxide nanoparticles for biomedical applications requires accurate histological evaluation. Prussian blue iron staining is widely used but may be unspecific when tissues contain substantial endogenous iron. Here we tested whether microscopy by laser ablation coupled to inductively coupled plasma mass spectrometry (LA-ICP-MS) is sensitive enough to analyze accumulation of very small iron oxide particles (VSOP) doped with europium in tissue sections. For synthesis of VSOP, a fraction of Fe3+ (5 wt%) was replaced by Eu3+, resulting in particles with 0.66 mol% europium relative to iron (Eu-VSOP) but with otherwise similar properties as VSOP. Eu-VSOP or VSOP was intravenously injected into ApoE-/- mice on Western cholesterol diet and accumulated in atherosclerotic plaques of these animals. Prussian blue staining was positive for ApoE-/- mice with particle injection but also for controls. LA-ICP-MS microscopy resulted in sensitive and specific detection of the europium of Eu-VSOP in liver and atherosclerotic plaques. Furthermore, calibration with Eu-VSOP allowed calculation of iron and particle concentrations in tissue sections. The combination of europium-doped iron oxide particles and LA-ICP-MS microscopy provides a new tool for specific and quantitative analysis of particle distribution at the tissue level and allows correlation with other elements such as endogenous iron.

  3. Novel Time-Resolved Fluorescence Europium Nanoparticle Immunoassay for Detection of Human Immunodeficiency Virus-1 Group O Viruses Using Microplate and Microchip Platforms.

    Science.gov (United States)

    Haleyur Giri Setty, Mohan Kumar; Liu, Jikun; Mahtani, Prerna; Zhang, Panhe; Du, Bingchen; Ragupathy, Viswanath; Devadas, Krishnakumar; Hewlett, Indira K

    2016-06-01

    Accurate detection and quantification of HIV-1 group O viruses have been challenging for currently available HIV assays. We have developed a novel time-resolved fluorescence (TRF) europium nanoparticle immunoassay for HIV-1 group O detection using a conventional microplate enzyme-linked immunosorbent assay (ELISA) and a microchip platform. We screened several antibodies for optimal reactivity with several HIV-1 group O strains and identified antibodies that can detect all the strains of HIV-1 group O that were available for testing. The antibodies were used to develop a conventional ELISA format assay and an in-house developed europium nanoparticle-based assay for sensitivity. The method was evaluated on both microwell plate and microchip platforms. We identified two specific and sensitive antibodies among the six we screened. The antibodies, C65691 and ANT-152, were able to quantify 15 and detect all 17 group O viruses, respectively, as they were broadly cross-reactive with all HIV-1 group O strains and yielded better signals compared with other antibodies. We have developed a sensitive assay that reflects the actual viral load in group O samples by using an appropriate combination of p24 antibodies that enhance group O detection and a highly sensitive TRF-based europium nanoparticle for detection. The combination of ANT-152 and C65690M in the ratio 3:1 was able to give significantly higher signals in our europium-based assay compared with using any single antibody.

  4. Lanthanide-to-lanthanide energy-transfer processes operating in discrete polynuclear complexes: can trivalent europium be used as a local structural probe?

    Science.gov (United States)

    Zaïm, Amir; Eliseeva, Svetlana V; Guénée, Laure; Nozary, Homayoun; Petoud, Stéphane; Piguet, Claude

    2014-09-15

    This work, based on the synthesis and analysis of chemical compounds, describes a kinetic approach for identifying intramolecular intermetallic energy-transfer processes operating in discrete polynuclear lanthanide complexes, with a special emphasis on europium-containing entities. When all coordination sites are identical in a (supra)molecular complex, only heterometallic communications are experimentally accessible and a Tb → Eu energy transfer could be evidenced in [TbEu(L5)(hfac)6] (hfac = hexafluoroacetylacetonate), in which the intermetallic separation amounts to 12.6 Å. In the presence of different coordination sites, as found in the trinuclear complex [Eu3(L2)(hfac)9], homometallic communication can be induced by selective laser excitation and monitored with the help of high-resolution emission spectroscopy. The narrow and non-degenerated character of the Eu((5)D0 ↔ (7)F0) transition excludes significant spectral overlap between donor and acceptor europium cations. Intramolecular energy-transfer processes in discrete polynuclear europium complexes are therefore limited to short distances, in agreement with the Fermi golden rule and with the kinetic data collected for [Eu3(L2)(hfac)9] in the solid state and in solution. Consequently, trivalent europium can be considered as a valuable local structural probe in discrete polynuclear complexes displaying intermetallic separation in the sub-nanometric domain, a useful property for probing lanthanido-polymers. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Optical isomers of N,N′-bis(1-phenylethyl)-2,6-pyridinedicarboxamide coordinated to europium(III) ions as reliable circularly polarized luminescence calibration standards†

    Science.gov (United States)

    Bonsall, Steven D.; Houcheime, Mona; Straus, Daniel A.; Muller, Gilles

    2009-01-01

    The synthesis of two optical isomers of N,N′-bis(1-phenylethyl)-2,6-pyridinedicarboxamide and the constant circularly polarized luminescence (CPL) activity of their acetonitrile trivalent europium complex solutions over a long period of time open new perspectives for performing accurate routine CPL calibration tests at low cost. PMID:17728891

  6. Photoluminescence behavior of europium (III) complexes containing 1-(4-tert-butylphenyl)-3-(2-naphthyl)-propane-1,3-dione ligand.

    Science.gov (United States)

    Wang, Dunjia; Zheng, Chunyang; Fan, Ling; Hu, Yanjun; Zheng, Jing

    2014-01-03

    Three novel europium complexes with 1-(4-tert-butylphenyl)-3-(2-naphthyl)-propane-1,3-dione (TNPD) and 2,2-dipyridine (Bipy) or 1,10-phenan-throline (Phen) were synthesized and confirmed by FT-IR, (1)H NMR, UV-vis absorption and elemental analysis. Photoluminescence behavior of complexes Eu(TNPD)3, Eu(TNPD)3·Bipy and Eu(TNPD)3·Phen were investigated in detail. Their emission spectra exhibited the characteristic emission bands that arise from the (5)D0→(7)FJ (J=0-4) transitions of the europium ion in solid state. Meanwhile, the results of their lifetime decay curves indicated that only one chemical environment existed around the europium ion. The intrinsic luminescence quantum efficiency (η) and the experimental intensity parameters (Ωt) of europium complexes were determined according to the emission spectra and luminescence decay curves in solid state. The complex Eu(TNPD)3·Phen showed much longer lifetime (τ) and higher luminescence quantum efficiency (η) than complexes Eu(TNPD)3 and Eu(TNPD)3·Bipy. Copyright © 2013 Elsevier B.V. All rights reserved.

  7. Synthesis, crystal structure and photophysical properties of europium(III) and terbium(III) complexes with pyridine-2,6-dicarboxamide

    NARCIS (Netherlands)

    Tanase, S.; Gallego, P.M.; Gelder, R. de; Fu, W.T.

    2007-01-01

    The reactions of pyridine-2,6-dicarboxamide with europium(III) and terbium(III) triflates led to the formation of mononuclear complexes of formula [Ln(pcam)(3)](CF3SO3)(3) (Ln = Eu 1, Tb 2; pcam stands for pyridine-2,6-dicarboxamide). From single-crystal X-ray diffraction analysis, the complexes

  8. Structural investigation and photoluminescent properties of gadolinium(III), europium(III) and terbium(III) 3-mercaptopropionate complexes.

    Science.gov (United States)

    Souza, E R; Mazali, I O; Sigoli, F A

    2014-01-01

    This work reports on the synthesis, crystallographic determination and spectroscopic characterization of gadolinium(III), terbium(III) and europium(III) 3-mercaptopropionate complexes, aqua-tris(3-mercaptopropionate)lanthanide(III)--[Ln(mpa)3(H2O)]. The Judd-Ofelt intensity parameters were experimentally determined from emission spectrum of the [Eu(mpa)3(H2O)]complex and they were also calculated from crystallographic data. The complexes are coordination polymers, where the units of each complex are linked together by carboxylate groups leading to an unidimensional and parallel chains that by chemical interactions form a tridimensional framework. The emission spectrum profile of the [Eu(mpa)3(H2O)] complex is discussed based on point symmetry of the europium(III) ion, that explains the bands splitting observed in its emission spectrum. Photoluminescent analysis of the [Gd(mpa)3(H2O)] complex show no efficient ligand excitation but an intense charge transfer band. The excitation spectra of the [Eu(mpa)3(H2O)] and [Tb(mpa)3(H2O)] complexes do not show evidence of energy transfer from the ligand to the excited levels of these trivalent ions. Therefore the emission bands are originated only by direct f-f intraconfigurational excitation of the lantanide(III) ions.

  9. Simple preparation of fluorescent composite films based on cerium and europium doped LaF3 nanoparticles

    Science.gov (United States)

    Secco, Henrique de L.; Ferreira, Fabio F.; Péres, Laura O.

    2018-03-01

    The combination of materials to form hybrids with unique properties, different from those of the isolated components, is a strategy used to prepare functional materials with improved properties aiming to allow their application in specific fields. The doping of lanthanum fluoride with other rare earth elements is used to obtain luminescent particles, which may be useful to the manufacturing of electronic devices' displays and biological markers, for instance. The application of the powder of nanoparticles has limitations in some fields; to overcome this, the powder may be incorporated in a suitable polymeric matrix. In this work, lanthanum fluoride nanoparticles, undoped and doped with cerium and europium, were synthesized through the co-precipitation method in aqueous solution. Aiming the formation of solid state films, composites of nanoparticles in an elastomeric matrix, the nitrile rubber (NBR), were prepared. The flexibility and the transparency of the matrix in the regions of interest are advantages for the application of the luminescent composites. The composites were applied as films using the casting and the spin coating techniques and luminescent materials were obtained in the samples doped with europium and cerium. Scanning electron microscopy images showed an adequate dispersion of the particles in the matrix in both film formation techniques. Aggregates of the particles were detected in the samples which may affect the uniformity of the emission of the composites.

  10. A microwave-assisted solution combustion synthesis to produce europium-doped calcium phosphate nanowhiskers for bioimaging applications.

    Science.gov (United States)

    Wagner, Darcy E; Eisenmann, Kathryn M; Nestor-Kalinoski, Andrea L; Bhaduri, Sarit B

    2013-09-01

    Biocompatible nanoparticles possessing fluorescent properties offer attractive possibilities for multifunctional bioimaging and/or drug and gene delivery applications. Many of the limitations with current imaging systems center on the properties of the optical probes in relation to equipment technical capabilities. Here we introduce a novel high aspect ratio and highly crystalline europium-doped calcium phosphate nanowhisker produced using a simple microwave-assisted solution combustion synthesis method for use as a multifunctional bioimaging probe. X-ray diffraction confirmed the material phase as europium-doped hydroxyapatite. Fluorescence emission and excitation spectra and their corresponding peaks were identified using spectrofluorimetry and validated with fluorescence, confocal and multiphoton microscopy. The nanowhiskers were found to exhibit red and far red wavelength fluorescence under ultraviolet excitation with an optimal peak emission of 696 nm achieved with a 350 nm excitation. Relatively narrow emission bands were observed, which may permit their use in multicolor imaging applications. Confocal and multiphoton microscopy confirmed that the nanoparticles provide sufficient intensity to be utilized in imaging applications. Copyright © 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  11. Europium nanoparticle-based simple to perform dry-reagent immunoassay for the detection of hepatitis B surface antigen.

    Science.gov (United States)

    Talha, Sheikh M; Salminen, Teppo; Juntunen, Etvi; Spangar, Anni; Gurramkonda, Chandrasekhar; Vuorinen, Tytti; Khanna, Navin; Pettersson, Kim

    2016-03-01

    Hepatitis B infection, caused by hepatitis B virus (HBV), presents a huge global health burden. Serological diagnosis of HBV mainly relies on the detection of hepatitis B surface antigen (HBsAg). Although there are high sensitivity commercial HBsAg enzyme immunoassays (EIAs) available, many low-resource laboratories lacking trained technicians continue to use rapid point-of-care assays with low sensitivities for HBsAg detection, due to their simplicity to operate. We developed a time-resolved fluorometric dry-reagent HBsAg immunoassay which meets the detection limit of high sensitivity EIAs but is simple to operate. To develop the assay, anti-HBsAg monoclonal antibody coated on europium nanoparticles was dried atop of biotinylated anti-HBsAg polyclonal antibody immobilized on streptavidin-coated microtiter wells. To test a sample in dry-reagent assay, serum sample and assay buffer were added to the wells, incubated, washed and europium signals were measured. The assay showed a detection limit of 0.25 ng/ml using HBsAg spiked in serum sample. When evaluated with 24 HBV positive and 37 negative serum samples, assay showed 100% sensitivity and specificity. Assay wells are stable for at least 26 weeks when stored at 4°C, and can tolerate elevated temperatures of up to 35°C for two weeks. The developed assay has high potential to be used in low-resource laboratories. Copyright © 2016 Elsevier B.V. All rights reserved.

  12. Bright mono-aqua europium complexes based on triazacyclononane that bind anions reversibly and permeate cells efficiently.

    Science.gov (United States)

    Butler, Stephen J; McMahon, Brian K; Pal, Robert; Parker, David; Walton, James W

    2013-07-15

    A series of five europium(III) complexes has been prepared from heptadentate N5O2 ligands that possess a brightness of more than 10 mM(-1) cm(-1) in water, following excitation over the range λ=330-355 nm. Binding of several oxy anions has been assessed by emission spectral titrimetric analysis, with the binding of simple carboxylates, lactate and citrate involving a common ligation mode following displacement of the coordinated water. Selectivity for bicarbonate allows the rapid determination of this anion in human serum, with K(d)=37 mM (295 K). The complexes are internalised quickly into mammalian cells and exhibit a mitochondrial localisation at early time points, migrating after a few hours to reveal a predominant lysosomal distribution. Herein, we report the synthesis and complexation behaviour of strongly emissive europium (III) complexes that bind oxy-anions in aqueous media with an affinity and selectivity profile that is distinctively different from previously studied systems. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Highly luminescent charge-neutral europium(iii) and terbium(iii) complexes with tridentate nitrogen ligands.

    Science.gov (United States)

    Senthil Kumar, Kuppusamy; Schäfer, Bernhard; Lebedkin, Sergei; Karmazin, Lydia; Kappes, Manfred M; Ruben, Mario

    2015-09-21

    We report on the synthesis of tridentate-nitrogen pyrazole-pyridine-tetrazole (L(1)H) and pyrazole-pyridine-triazole (L(2)H) ligands and their complexation with lanthanides (Ln = Gd(iii), Eu(iii) and Tb(iii)) resulting in stable, charge-neutral complexes Ln(L(1))3 and Ln(L(2))3, respectively. X-ray crystallographic analysis of the complexes with L(1) ligands revealed tricapped trigonal coordination geometry around the lanthanide ions. All complexes show bright photoluminescence (PL) in the solid state, indicating efficient sensitization of the lanthanide emission via the triplet states of the ligands. In particular, the terbium complexes show high PL quantum yields of 65 and 59% for L(1) and L(2), respectively. Lower PL efficiencies of the europium complexes (7.5 and 9%, respectively) are attributed to large energy gaps between the triplet states of the ligands and accepting levels of Eu(iii). The triplet state energy can be reduced by introducing an electron withdrawing (EW) group at the 4 position of the pyridine ring. Such substitution of L(1)H with a carboxylic ester (COOMe) EW group leads to a europium complex with increased PL quantum yield of 31%. A comparatively efficient PL of the complexes dissolved in ethanol indicates that the lanthanide ions are shielded against nonradiative deactivation via solvent molecules.

  14. Highly Sensitive Luminescence Assessment of Bile Acid Using a Balofloxacin-Europium(III) Probe in Micellar Medium

    Energy Technology Data Exchange (ETDEWEB)

    Cai, Huan; Zhao, Fang; Si, Hailin; Zhang, Shuaishuai; Wang, Chunchun; Qi, Peirong [Shihezi Univ., Shihezi (China)

    2012-12-15

    A novel and simple method of luminescence enhancement effect for the determination of trace amounts of bile acid was proposed. The procedure was based on the luminescence intensity of the balofloxacin-europium(III) complex that could be strongly enhanced by bile acid in the presence of sodium dodecyl benzene sulfonate (SDBS). Under the optimum conditions, the enhanced luminescence intensity of the system exhibited a good linear relationship with the bile acid concentration in the range 5.0 Χ 10{sup -9} - 7.0 Χ 10{sup -7} mol L{sup -1} with a detection limit of 1.3 Χ 10{sup -9} mol L.1 (3σ). The relative standard deviation (RSD) was 1.7% (n = 11) for 5.0 Χ 10{sup -8} mol L{sup -1} bile acid. The applicability of the method to the determination of bile acid was demonstrated by investigating the effect of potential interferences and by analyzing human serum and urine samples. The possible enhancement mechanism of luminescence intensity in balofloxacin-europium(III)-bile acid-SDBS system was also discussed briefly.

  15. Investigation of the influence of silver and tin on the luminescence of trivalent europium ions in glass

    Energy Technology Data Exchange (ETDEWEB)

    Jimenez, J.A. [Department of Chemistry, University of Puerto Rico, Mayagueez, PR 00681 (United States); Lysenko, S. [Department of Physics, University of Puerto Rico, Mayagueez, PR 00681 (Puerto Rico); Liu, H., E-mail: hliu@uprm.ed [Department of Physics, University of Puerto Rico, Mayagueez, PR 00681 (Puerto Rico); Fachini, E.; Cabrera, C.R. [Center for Nanoscale Materials, University of Puerto Rico, Rio Piedras, PR 00931 (Puerto Rico)

    2010-01-15

    Europium-doped aluminophosphate glasses prepared by the melt-quenching technique have been studied by photoluminescence (PL) and X-ray photoelectron spectroscopy (XPS). The effects of silver and tin doping, and of further thermal processing on Eu{sup 3+} ions luminescence have been assessed. For the glass system containing only europium, Eu{sup 3+} PL observed under UV excitation is suggested to occur through energy transfer from the excited glass host. After silver and tin doping, an enhanced UV excited Eu{sup 3+} PL has been indicated to occur essentially due to radiative energy transfer from isolated Ag{sup +} ions and/or two fold-coordinated Sn centers. Since thermal processing of the material leads to a quenching effect on Eu{sup 3+} PL and Ag nanoparticles (NPs) formation due to reduction of silver ions by tin, XPS was employed in order to investigate the possibility for Eu{sup 3+}->Eu{sup 2+} reduction during HT as a potential source of the PL decrease. The data points towards Ag NPs as main responsible for the observed weakening of Eu{sup 3+} PL.

  16. Non-conservative controls on distribution of dissolved silicate in Cochin Backwaters

    Digital Repository Service at National Institute of Oceanography (India)

    Balachandran, K.K.; Sankaranarayanan, V.N.; Joseph, T.; Nair, M.

    Cochin backwater system was studied with regard to dissolved silicate (DSi) to understand its seasonal distribution and behaviour during estuarine mixing. Silicate had a linear relationship with salinity during the high river discharge period...

  17. Quantitative Estimation of the Reinforcing Effect of Layered Silicates in PP Nanocomposites

    NARCIS (Netherlands)

    Szazdi, Laszlo; Pukansky Jr, Bela; Vancso, Gyula J.; Pukanszky, B.; Pukanszky, Bela

    2006-01-01

    Various polypropylene/layered silicate composites were prepared with different silicate contents. Montmorillonites with and without organophilization as well as three maleinated polypropylenes were used to change the extent of exfoliation and hence the properties of the composites. Structure was

  18. PETROLOGY AND GEOCHEMISTRY OF CALC-SILICATE SCHISTS ...

    African Journals Online (AJOL)

    DR OKONKOWO

    2012-02-29

    Feb 29, 2012 ... Calc-silicate diffusion zones between marble and pelitic schist. Journal of. Petrology, 16, 314-346. Turner, D. C., 1983. Upper Proterozoic Schist Belts in the Nigerian sector of the Pan-African province of West Africa. Precambrian Research, 21, 55-. 79. Van de Kamp, P. C., 1968. Geochemistry and origin of.

  19. Dry phosphorus silicate glass etching for multicrystalline silicon solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Nositschka, W.A.; Voigt, O.; Kurz, H. [Aachen Univ. (Germany). Inst. of Semiconductor Electronics; Kenanoglu, A.; Borchert, D. [Fraunhofer Inst. for Solar Energy Systems, Gelsenkirchen (Germany)

    2003-07-01

    A dry plasma etching process for phosphorus silicate glass (PSG) in a SiN-PECVD batch reactor is developed. In the same reactor PSG etching and anti-reflective coating (ARC) can be performed successively. To demonstrate industrial feasibility, screen-printed solar cells are manufactured and compared with cells prepared by a standard wet chemical process. (Author)

  20. Effects of Mixed Alkaline Earth Oxides in Potash Silicate Glass ...

    African Journals Online (AJOL)

    The aim of this work is to investigate the effects of mixed alkaline earth oxide in potash silicate glasses with regards to their physical properties. More recently; there has been an increase in the demand for light weight glasses which retains their physical and chemical properties for both domestic and industrial applications.

  1. High-pressure physical properties of magnesium silicate post ...

    Indian Academy of Sciences (India)

    dLaboratory for Shock Wave and Detonation Physics Research, Institute of Fluid Physics, Academy of Engineering. Physics, PO Box 919-102, Mianyang 621900, China. MS received 1 May 2011. Abstract. The structure, thermodynamic and elastic properties of magnesium silicate (MgSiO3) post-perovskite at high pressure ...

  2. Vesuvianite–wollastonite–grossular-bearing calc-silicate rock near ...

    Indian Academy of Sciences (India)

    This paper reports the occurrence of vesuvianite + wollastonite + grossular + diopside + microcline + quartz assemblage in an enclave of calc-silicate rocks occurring within quartzofeldspathic gneiss near Tatapani in the western part of Chhotanagpur Gneissic Complex. The enclave contains phlogopite-absent and ...

  3. Effects of Aluminium–Magnesium Silicate on Newcastle Disease ...

    African Journals Online (AJOL)

    Effect of a synthetic Aluminium – Magnesium Silicate (AMS) on Newcastle Disease Virus (NDV) was tested. Equal amounts, of the AMS and of NDV, on a volume to weight (v/w) basis, were incubated for one hour at room temperature, and then centrifuged. The supernatant was tested for NDV titre. Portions of a virulent NDV ...

  4. Preparation and characterization of magnesium–aluminium–silicate ...

    Indian Academy of Sciences (India)

    A three-stage heating schedule involving calcination, nucleation and crystallization, has been evolved for the preparation of magnesium aluminium silicate (MAS) glass ceramic with MgF2 as a nucleating agent. The effect of sintering temperature on the density of compacted material was studied. Microstructure and ...

  5. Determination of reactivity rates of silicate particle-size fractions

    Directory of Open Access Journals (Sweden)

    Angélica Cristina Fernandes Deus

    2014-04-01

    Full Text Available The efficiency of sources used for soil acidity correction depends on reactivity rate (RR and neutralization power (NP, indicated by effective calcium carbonate (ECC. Few studies establish relative efficiency of reactivity (RER for silicate particle-size fractions, therefore, the RER applied for lime are used. This study aimed to evaluate the reactivity of silicate materials affected by particle size throughout incubation periods in comparison to lime, and to calculate the RER for silicate particle-size fractions. Six correction sources were evaluated: three slags from distinct origins, dolomitic and calcitic lime separated into four particle-size fractions (2, 0.84, 0.30 and <0.30-mm sieves, and wollastonite, as an additional treatment. The treatments were applied to three soils with different texture classes. The dose of neutralizing material (calcium and magnesium oxides was applied at equal quantities, and the only variation was the particle-size material. After a 90-day incubation period, the RER was calculated for each particle-size fraction, as well as the RR and ECC of each source. The neutralization of soil acidity of the same particle-size fraction for different sources showed distinct solubility and a distinct reaction between silicates and lime. The RER for slag were higher than the limits established by Brazilian legislation, indicating that the method used for limes should not be used for the slags studied here.

  6. Estimation of high temperature metal-silicate partition coefficients

    Science.gov (United States)

    Jones, John H.; Capobianco, Christopher J.; Drake, Michael J.

    1992-12-01

    It has been known for some time that abundances of siderophile elements in the upper mantle of the Earth are far in excess of those expected from equilibrium between metal and silicate at low pressures and temperatures. Murthy (1991) has re-examined this excess of siderophile element problem by estimating liquid metal/liquid silicate partition coefficients reduces from their measured values at a lower temperature, implying that siderophile elements become much less siderophilic at high temperatures. Murthy then draws the important conclusion that metal/silicate equilibrium at high temperatures can account for the abundances of siderophile elements in the Earth's mantle. Of course, his conclusion is critically dependent on the small values of the partition coefficients he calculates. Because the numerical values of most experimentally-determined partition coefficients increase with increasing temperature at both constant oxygen fugacity and at constant redox buffer, we think it is important to try an alternative extrapolation for comparison. We have computed high temperature metal/silicate partition coefficients under a different set of assumptions and show that such long temperature extrapolations yield values which are critically dependent upon the presumed chemical behavior of the siderophile elements in the system.

  7. In vitro bioactivity and cytocompatibility of tricalcium silicate

    Indian Academy of Sciences (India)

    In vitro cytocompatible evaluation reveals that osteoblasts adhere and spread well on the Ca3SiO5 ceramics, indicating good bioactivity and cytocompatibility. Keywords. Tricalcium silicate; bioactivity; cytocompatibility; hydroxyapatite; osteoblasts. 1. Introduction. Up to now, many bioactive biomaterials, such as A/W glass.

  8. Mineralogy and trace element chemistry of the Siliceous Earth of ...

    Indian Academy of Sciences (India)

    R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

    We report the presence of a 3–5 cm thick loose fragmental layer in the Siliceous Earth at Matti ka. Gol in the Barmer basin of Rajasthan. Petrographic, chemical and mineralogical study reveals the presence of abundant volcanic debris such as glass shards, agglutinates, hollow spheroids, kinked biotites, feldspars showing ...

  9. Potassium silicate-zinc oxide solution for metal finishes

    Science.gov (United States)

    Schutt, J. B.

    1970-01-01

    Examples of zinc dust formulations, which are not subject to cracking or crazing, are fire retardant, and have high adhesive qualities, are listed. The potassium silicate in these formulations has mol ratios of dissolved silica potassium oxide in the range 4.8 to 1 - 5.3 to 1.

  10. Fluoroalkylsilane versus Alkylsilane as Hydrophobic Agents for Silica and Silicates

    Directory of Open Access Journals (Sweden)

    Damian Ambrożewicz

    2013-01-01

    Full Text Available Hydrophobic powders were obtained via surface modification of silica or magnesium silicate with selected silanes. A modified precipitation method, carried out in an emulsion system, was used for monodisperse silica synthesis, while magnesium silicate was precipitated in a traditional water system. Functionalization of the obtained inorganic supports was performed with selected alkylsilanes: one newly synthesized, 3-(2,2,3,3,4,4,5,5-octafluoropentyloxypropyltriethoxysilane (OPF, and two commercial, octadecylsilane (ODS and octyltriethoxysilane C14H32O3Si (OCS, in amounts of 3, 5, or 10 weight parts by mass of SiO2. It was determined how the chemical modification of the silica or magnesium silicate surface affected its physicochemical properties. The dispersive characteristics of both unmodified and functionalized silica-based systems were evaluated. The morphology and microstructure of the samples obtained were analyzed using scanning electron microscopy. The parameters of porous structure of the prepared systems were evaluated on the basis of BET equation as well as nitrogen adsorption/desorption isotherms. Wettability tests as well as elemental analysis of the obtained inorganic oxide hybrids were also performed. In order to verify the effectiveness of silica and magnesium silicate surface functionalization with selected silanes, FTIR spectra were investigated. The resulting experimental data allowed calculation of the degree of coverage of the silica-based systems with modifying agents.

  11. Evaluation of Calcium Silicate Cement Bond Strength after Using ...

    African Journals Online (AJOL)

    2018-01-24

    Jan 24, 2018 ... Objectives: To determine the effect of different gutta‑percha solvents. (chloroform, Endosolv E, orange oil, and eucalyptol) on the push‑out bond strength of calcium silicate cements (CSCs; white mineral trioxide aggregate. [WMTA]; capsule‑form mineral trioxide aggregate [CMTA], and Biodentine). Materials ...

  12. Energetics of silicate melts from thermal diffusion studies

    Energy Technology Data Exchange (ETDEWEB)

    Walker, D.

    1992-07-01

    Efforts are reported in the following areas: laboratory equipment (multianvils for high P/T work, pressure media, SERC/DL sychrotron), liquid-state thermal diffusion (silicate liquids, O isotopic fractionation, volatiles, tektites, polymetallic sulfide liquids, carbonate liquids, aqueous sulfate solutions), and liquid-state isothermal diffusion (self-diffusion, basalt-rhyolite interdiffusion, selective contamination, chemical diffusion).

  13. 77 FR 21676 - Silicic Acid, Sodium Salt etc.; Tolerance Exemption

    Science.gov (United States)

    2012-04-11

    ... chlorotrimethylsilane and iso-propyl alcohol, reaction with poly(oxypropylene)-poly(oxyethylene) glycol; when used as an... residues of Silicic acid, sodium salt, reaction products with chlorotrimethylsilane and iso-propyl alcohol...-OPP-2011-0934, by one of the following methods. Federal eRulemaking Portal: http://www.regulations.gov...

  14. Ubiquitous high-FeO silicates in enstatite chondrites

    Science.gov (United States)

    Lusby, David; Scott, Edward R. D.; Keil, Klaus

    1987-01-01

    SEM and EMPA were used to determine the mineral contents of four EH3 chondrites. All four showed the dominant enstatite peak, Fs 0-5, with 4-8 percent of FeO-rich pyroxene with Fs 5-20. Among the 542 objects found to contain high-FeO silicates, 18 were chondrules, 381 were rimmed or unrimmed grains, and 143 were aggregates. The high-FeO silicates in these objects are very largely pyroxene with Fs 5-23. Large grains of both FeO-rich and FeO-poor silicates were found to be present in the FeO-rich chondrules. This fact, together with the absence of clasts of FeO-rich chondritic material in the EH3 chondrites, suggests that FeO-rich grains were introduced before or during chondrule formation. It is concluded that FeO-rich and FeO-poor silicates were both present in the nebular region where E chondrites originated.

  15. Mineralogy and trace element chemistry of the Siliceous Earth of ...

    Indian Academy of Sciences (India)

    We report the presence of a 3-5 cm thick loose fragmental layer in the Siliceous Earth at Matti ka Gol in the Barmer basin of Rajasthan. Petrographic, chemical and mineralogical study reveals the presence of abundant volcanic debris such as glass shards, agglutinates, hollow spheroids, kinked biotites, feldspars showing ...

  16. Oxygen from the lunar soil by molten silicate electrolysis

    Science.gov (United States)

    Colson, Russell O.; Haskin, Larry A.

    1992-01-01

    Accepting that oxygen, rather than gigantic gems or gold, is likely to make the Moon's Klondike, the extraction of oxygen from the lunar soil by molten silicate electrolysis has chosen to be investigated. Process theory and proposed lunar factory are addressed.

  17. A Siliceous Microfossil View of Middle Eocene Arctic Paleoenvironments

    Science.gov (United States)

    Stickley, C. E.; Koc, N.; Brumsack, H.; Jordan, R. W.; Suto, I.

    2007-12-01

    Integrated Ocean Drilling Program Expedition 302, "The Arctic Coring Expedition" (ACEX) made arguably the most significant discovery of Paleogene siliceous microfossils in nearly 2 decades. 100 m of mm to sub-mm laminated biosiliceous sediments of Middle Eocene age are rich in marine and freshwater siliceous microfossils allowing intriguing insights into central Arctic paleoenvironments during the start of Cenozoic cooling to icehouse conditions. Largely endemic assemblages of marine diatoms and ebridians are preserved along with very high abundances of chrysophyte cysts, the endogenously formed resting stage of freshwater algae. These siliceous microfossil groups imply an overall brackish environment, but variations in group dominance suggest episodic variations in salinity, stratification and trophic status. We synthesize the overall characteristics of the biosiliceous sediments by reporting on broad scale variations in siliceous microfossils and give some exciting insights into the composition of the laminae which may help explain the formation of these sediments. Our results indicate basin-wide paleo-environmental fluctuations on long- and possibly seasonal timescales.

  18. Mesoporous silicates: Materials science and biological applications

    Science.gov (United States)

    Roggers, Robert Anthony

    This thesis dissertation presents the collective research into the advancement of mesoporous silicate particles as biointerface devices, the development of new materials and the application of these particles as solid supports for heterogeneous catalysis. Mesoporous silica has been utilized in the aforementioned applications due to several reasons; the first being the ability to achieve high surface areas (500 - 1000 m2 g-1) with controlled pore sizes and particle morphology. Another reason for their popularity is their robustness in applications of heterogeneous catalysis and the ability to functionalize the surface with a wide variety of organic functional groups. In the field of biointerface devices, mesoporous silica nanoparticles represent a class of materials that exhibit high biocompatibility. In addition, the ability to functionalize the surfaces (outer surface and pore interiors) allows the particles to be targeted to specific cell types as well as the ability to release many different therapeutic molecules under specific stimuli. A unique particle coating consisting of a chemically cleavable lipid bilayer that allows for the encapsulation of a fluorescent molecule and increases the biocompatibility of the particle has been developed. The lipid bilayer coated mesoporous silica nanoparticle (LB-MSN) was characterized using X-ray diffraction, transmission electron microscopy and nitrogen `sorption isotherms. The finished LB-MSN was then incubated with mammalian cells in order to prove their biocompatibility. Confocal micrographs demonstrate the endocytosis of the particles into the cells. In addition the micrographs also show that the LB-MSNs are separate from the endosomal compartments, however due to the lipophilic nature of the dye used to label the endosome there is some debate regarding this conclusion. The lipid bilayer coating was then applied to a large pore MSN (l-MSN) which had been previously shown to cause lysis of red blood cells (RBCs) at low

  19. Behaviour of europium (III) and its hydroxo and carbonate complexes in a solvent extraction system with HDBM in 2 M NaCl at 303 K

    Energy Technology Data Exchange (ETDEWEB)

    Jimenez-Reyes, M. [Inst. Nacional de Investigaciones Nucleares, Dept. de Quimica, Mexico, D. F. (Mexico); Univ. Autonoma Metropolitana-Iztapalapa, Area de Electroquimica, Mexico, D. F. (Mexico); Solache-Rios, M. [Inst. Nacional de Investigaciones Nucleares, Dept. de Quimica, Mexico, D. F. (Mexico); Rojas-Hernandez, A. [Univ. Autonoma Metropolitana-Iztapalapa, Area de Electroquimica, Mexico, D. F. (Mexico)

    1999-07-01

    The behaviour of europium in the solvent extraction system Eu{sup 3+}-water-2 M NaCl-HDBM-benzene was studied, taking into account the pC{sub H} and the carbonate ion concentration in the solutions. The stability constants for the hydrolysis and carbonate complexes of europium were determined at 303 K in the same medium by pH titration followed by a computational refinement. The obtained data were: log {beta}{sub Eu,H} = -8.29 {+-} 0.02, log {beta}{sub Eu,2H} = -16.37 {+-} 0.02, log {beta}{sub Eu,3H} = -24.54 {+-} 0.11, log {beta}{sub Eu,4H} = -34.91 {+-} 0.26, log {beta}{sub CO{sub 2}{sup 2-},H} = 9.30 {+-} 0.05, log {beta}{sub Eu,CO{sub 3}{sup 2-}} = 5.96 {+-} 0.03, log {beta}{sub Eu,CO{sub 3}{sup 2-},H} = -1.24 {+-} 0.05 and log {beta}{sub Eu,CO{sub 3}{sup 2-},2H} = -11.39 {+-} 0.11. Log K{sub W} was -13.78 {+-} 0.06. The behaviour of europium in this solvent extraction system was simulated, taking into account the hydrolysis and carbonate complexes plus the formation of Eu(DBM){sub 3}(OH){sup 1-} and Eu(DBM){sub 3}(CO{sub 3}){sup 2-} in the aqueous phase. The only europium species considered in the organic phase was Eu(DBM){sub 3}. The first hydrolysis constant of europium was also determined by using this solvent extraction system under the same conditions. A good conformity was found with the results obtained by both techniques. (orig.)

  20. Bis(acridine-9-carboxylate)-nitro-europium(III) dihydrate complex a new apoptotic agent through Flk-1 down regulation, caspase-3 activation and oligonucleosomes DNA fragmentation.

    Science.gov (United States)

    Azab, Hassan A; Hussein, Belal H M; El-Azab, Mona F; Gomaa, Mohamed; El-Falouji, Abdullah I

    2013-01-01

    New bis(acridine-9-carboxylate)-nitro-europium(III) dihydrate complex was synthesized and characterized. In vivo anti-angiogenic activities of bis(acridine-9-carboxylate)-nitro-europium(III) dihydrate complex against Ehrlich ascites carcinoma (EAC) cells are described. The newly synthesized complex resulted in inhibition of proliferation of EAC cells and ascites formation. The anti-tumor effect was found to be through anti-angiogenic activity as evident by the reduction of microvessel density in EAC solid tumors. The anti-angiogenic effect is mediated through down-regulation of VEGF receptor type-2 (Flk-1). The complex was also found to significantly increase the level of caspase-3 in laboratory animals compared to the acridine ligand and to the control group. This was also consistent with the DNA fragmentation detected by capillary electrophoresis that proved the apoptotic effect of the new complex. Our complex exhibited anti-angiogenic and apoptotic activity in vivo, a thing that makes it a potential effective chemotherapeutic agent. The interaction of calf thymus DNA (ct-DNA) with bis(acridine-9-carboxylate)-nitro-europium(III) dihydrate complex has been investigated using fluorescence technique. A competitive experiment of the europium(III)-acridine complex with ethidium bromide (EB) to bind DNA revealed that interaction between the europium(III)-acridine and DNA was via intercalation. The interaction of the synthesized complex with tyrosine kinases was also studied using molecular docking simulation to further substantiate its mode of action. Copyright © 2012 Elsevier Ltd. All rights reserved.

  1. Silicate Dispersion and Mechanical Reinforcement in Polysiloxane/Layered Silicate Nanocomposites

    KAUST Repository

    Schmidt, Daniel F.

    2010-01-12

    We report the first in-depth comparison of the mechanical properties and equilibrium solvent uptake of a range of polysiloxane nanocomposites based on treated and untreated montmorillonite and fumed silica nanofillers. We demonstrate the ability of equilibrium solvent uptake data (and, thus, overall physical and chemical cross-link density) to serve as a proxy for modulus (combining rubber elasticity and Flory-Rehner theory), hardness (via the theory of Boussinesq), and elongation at break, despite the nonideal nature of these networks. In contrast, we find that tensile and tear strength are not well-correlated with solvent uptake. Interfacial strength seems to dominate equilibrium solvent uptake and the mechanical properties it predicts. In the montmorillonite systems in particular, this results in the surprising consequence that equilibrium solvent uptake and mechanical properties are independent of dispersion state. We conclude that edge interactions play a more significant role than degree of exfoliation, a result unique in the field of polymer nanocomposites. This demonstrates that even a combination of polymer/nanofiller compatibility and thermodynamically stable nanofiller dispersion levels may not give rise to reinforcement. These findings provide an important caveat when attempting to connect structure and properties in polymer nanocomposites, and useful guidance in the design of optimized polymer/layered silicate nanocomposites in particular. © 2009 American Chemical Society.

  2. Production test IP-728 half-plant sodium silicate test. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Geier, R.G.

    1966-07-28

    The sodium silicate addition to the coolant reduced the effluent concentrations of certain radionuclides. Nothing was observed during the course of the test to indicate that sodium silicate could not be used at all plants. However, the reductions obtained in effluent activity are not believed commensurate with the cost of silicate usage.

  3. Silicate Phases on the Surfaces of Trojan Asteroids

    Science.gov (United States)

    Martin, Audrey; Emery, Joshua P.; Lindsay, Sean S.

    2017-10-01

    Determining the origin of asteroids provides an effective means of constraining the solar system’s dynamic past. Jupiter Trojan asteroids (hereafter Trojans) may help in determining the amount of radial mixing that occurred during giant planet migration. Previous studies aimed at characterizing surface composition show that Trojans have low albedo surfaces and are spectrally featureless in the near infrared. The thermal infrared (TIR) wavelength range has advantages for detecting silicates on low albedo asteroids such as Trojans. The 10 μm region exhibits strong features due to the Si-O fundamental molecular vibrations. Silicates that formed in the inner solar system likely underwent thermal annealing, and thus are crystalline, whereas silicates that accreted in the outer solar system experienced less thermal processing, and therefore are more likely to have remained in an amorphous phase. We hypothesize that the Trojans formed in the outer solar system (i.e., the Kuiper Belt), and therefore will have a more dominant amorphous spectral silicate component. With TIR spectra from the Spitzer Space Telescope, we identify mineralogical features from the surface of 11 Trojan asteroids. Fine-grain mixtures of crystalline pyroxene and olivine exhibit a 10 μm feature with sharp cutoffs between about 9 μm and 12 μm, which create a broad flat plateau. Amorphous phases, when present, smooth the sharp emission features, resulting in a dome-like shape. Preliminary results indicate that the surfaces of analyzed Trojans contain primarily amorphous silicates. Emissivity spectra of asteroids 1986 WD and 4709 Ennomos include small peaks in the 10 μm region, diagnostic of small amounts of crystalline olivine. One explanation is that Trojans formed in the same region as Kuiper Belt objects, and when giant planet migration ensued, they were swept into Jupiter’s stable Lagrange points where they are found today. As such, it is possible that an ancestral group of Kuiper Belt

  4. Wastewater reuse in liquid sodium silicate manufacturing in alexandria, egypt.

    Science.gov (United States)

    Ismail, Gaber A; Abd El-Salam, Magda M; Arafa, Anwar K

    2009-01-01

    Soluble sodium silicates (waterglass) are liquids containing dissolved glass which have some water like properties. They are widely used in industry as sealants, binders, deflocculants, emulsifiers and buffers. Their most common applications in Egypt are in the pulp and paper industry (where they improve the brightness and efficiency of peroxide bleaching) and the detergent industry, in which they improve the action of the detergent and lower the viscosity of liquid soaps. The survey results showed that the production was carried out batch-wise, in an autoclave (dissolver). Sodium silicate in the state of crushed glass was charged in an autoclave (dissolver) with sodium hydroxide and water. The product is filtered through a press. The left over sludge (mud and silicates impurities) is emptied into the local sewer system. Also, sludge (silica gel) was discharged from the neutralization process of the generated alkaline wastewater and consequently clogging the sewerage system. So this study was carried out to modify the current wastewater management system which eliminates sludge formation, the discharge of higher pH wastewater to the sewer system, and to assess its environmental and economic benefits. To assess the characteristics of wastewater to be reused, physico-chemical parameters of 12 samples were tested using standard methods. The survey results showed that a total capacity of the selected enterprise was 540 tons of liquid sodium silicates monthly. The total amount of wastewater being discharged was 335 m3/month. Reusing of wastewater as feed autoclave water reduced water consumption of 32.1% and reduced wastewater discharge/month that constitutes 89.6% as well as saving in final product of 6 ton/month. It was concluded that reusing of wastewater generated from liquid sodium silicate manufacturing process resulted in cheaper and environmental-friendly product.

  5. Effect of silicate module of water glass on rheological parameters of poly(sodium acrylate)/sodium silicate hydrogels

    Science.gov (United States)

    Mastalska-Popiawska, J.; Izak, P.

    2017-01-01

    The poly(sodium acrylate)/sodium silicate hydrogels were synthesized in the presence of sodium thiosulphate and potassium persulphate as the redox initiators and N,N’-methylene-bisacrylamide as the cross-linking monomer. 20 wt% aqueous solution of sodium acrylate was polymerized together with water glass with different silicate modules (M) from 1.74 to 2.29, in three mass ratio of the monomer solution to the water glass 2:1, 1:1 and 1:2. Such obtained hybrid composites were rheologically tested using the oscillation method. It allowed to designate the crossover point during polymerization, as well as to define the viscoelastic properties of the casted hydrogel samples one week after the reaction. The obtained results of the oscillation measurements showed that cross-linking reaction proceeds very quickly and the lower the silicate module is, the process starts faster. After the completion of the reaction the silicate-polymer hydrogels are strongly elastic materials and the highest elasticity characterizes systems with the mass ratio 1:2, i.e. with the highest water glass content.

  6. Europium(III) reduction and speciation within a Wells-Dawson heteropolytungstate.

    Science.gov (United States)

    Jing, Jing; Burton-Pye, Benjamin P; Francesconi, Lynn C; Antonio, Mark R

    2008-08-04

    The redox speciation of Eu(III) in the 1:1 stoichiometric complex with the alpha-1 isomer of the Wells-Dawson anion, [alpha-1-P 2W 17O 61] (10-), was studied by electrochemical techniques (cyclic voltammetry and bulk electrolysis), in situ XAFS (X-ray absorption fine structure) spectroelectrochemistry, NMR spectroscopy ( (31)P), and optical luminescence. Solutions of K 7[(H 2O) 4Eu(alpha-1-P 2W 17O 61)] in a 0.2 M Li 2SO 4 aqueous electrolyte (pH 3.0) show a pronounced concentration dependence to the voltammetric response. The fully oxidized anion and its reduced forms were probed by Eu L 3-edge XANES (X-ray absorption near edge structure) measurements in simultaneous combination with controlled potential electrolysis, demonstrating that Eu(III) in the original complex is reduced to Eu(II) in conjunction with the reduction of polyoxometalate (POM) ligand. After exhaustive reduction, the heteropoly blue species with Eu(II) is unstable with respect to cluster isomerization, fragmentation, and recombination to form three other Eu-POMs as well as the parent Wells-Dawson anion, alpha-[P 2W 18O 62] (6-). EXAFS data obtained for the reduced, metastable Eu(II)-POM before the onset of Eu(II) autoxidation provides an average Eu-O bond length of 2.55(4) A, which is 0.17 A longer than that for the oxidized anion, and consistent with the 0.184 A difference between the Eu(II) and Eu(III) ionic radii. The reduction of Eu(III) is unusual among POM complexes with Lindqvist and alpha-2 isomers of Wells-Dawson anions, that is, [Eu(W 5O 18) 2] (9-) and [Eu(alpha-2-As 2W 17O 61) 2] (17-), but not to the Preyssler complex anion, [EuP 5W 30O 110] (12-), and fundamental studies of materials based on coupling Eu and POM redox properties are still needed to address new avenues of research in europium hydrometallurgy, separations, and catalysis sciences.

  7. Structural, optical and electrical properties of europium picrate tetraethylene glycol complex as emissive material for OLED

    Energy Technology Data Exchange (ETDEWEB)

    Kusrini, Eny, E-mail: ekusrini@che.ui.ac.id [Department of Chemical Engineering, Faculty of Engineering, Universitas Indonesia, 16424 Depok (Indonesia); Saleh, Muhammad I.; Adnan, Rohana [School of Chemical Sciences, Universiti Sains Malaysia, 11800 Penang (Malaysia); Yulizar, Yoki [Department of Chemistry, Faculty of Mathematics and Natural Sciences, Universitas Indonesia, 16424 Depok (Indonesia); Sha Shiong, Ng; Fun, H.K. [School of Physics, Universiti Sains Malaysia, 11800 Penang (Malaysia); Adhha Abdullah, M.A.; Mamat, Mazidah [Department of Chemical Sciences, Faculty of Science and Technology, Universiti Malaysia Terengganu, 21030 Kuala Terengganu, Terengganu Darul Iman (Malaysia); Za' aba, N.K.; Abd. Majid, W.H. [Solid State Research Laboratory, Department of Physics, Universiti Malaya, 50603 Kuala Lumpur (Malaysia)

    2012-01-15

    A new europium complex [Eu(Pic){sub 2}(H{sub 2}O)(EO4)](Pic).0.75H{sub 2}O was synthesized and used as the emission material for the single layer device structure of ITO/EO4-Eu-Pic/Al, using a spin-coating technique. Study on the optical properties of the [Eu(Pic){sub 2}(H{sub 2}O)(EO4)](Pic).0.75H{sub 2}O complex where EO4=tetraethylene glycol and Pic=picrate anion, had to be undertaken before being applicable to the study of an organic light emitting diode (OLED). The electrical property of an OLED using current-voltage (I-V) measurement was also studied. In complex, the Eu(III) ion was coordinated with the EO4 ligand as a pentadentate mode, one water molecule, and with two Pic anions as bidentate and monodentate modes, forming a nine-coordination number. The photoluminescence (PL) spectra of the crystalline complex in the solid state and its thin film showed a hypersensitive peak at 613.5-614.9 nm that assigned to the {sup 5}D{sub 0}{yields}{sup 7}F{sub 2} transition. A narrow band emission from the thin film EO4-Eu-Pic was obtained. The typical semiconductor I-V curve of device ITO/EO4-Eu-Pic/Al showed the threshold and turn on voltages at 1.08 and 4.6 V, respectively. The energy transfer process from the ligand to the Eu(III) ion was discussed by investigating the excitation and PL characteristics. Effect of the picrate anion on the device performance was also studied. - Highlights: > The [Eu(Pic){sub 2}(H{sub 2}O)(EO4)](Pic).0.75(H{sub 2}O) is crystallized in triclinic with space group P-1. > The complex is applied as a emissive center in single layer device structure of ITO/EO4-Eu-Pic/Al. > The complex displays a red luminescence in both the crystalline complex and its thin film state. > The low turn on voltage of the device (4.6 V), indicating that this material is suitable for OLED. > The roughness and morphology of the thin film affects luminance and electrical properties of OLED.

  8. Biological and therapeutic effects of ortho-silicic acid and some ortho-silicic acid-releasing compounds: New perspectives for therapy

    Directory of Open Access Journals (Sweden)

    Jurkić Lela Munjas

    2013-01-01

    Full Text Available Abstract Silicon (Si is the most abundant element present in the Earth's crust besides oxygen. However, the exact biological roles of silicon remain unknown. Moreover, the ortho-silicic acid (H4SiO4, as a major form of bioavailable silicon for both humans and animals, has not been given adequate attention so far. Silicon has already been associated with bone mineralization, collagen synthesis, skin, hair and nails health atherosclerosis, Alzheimer disease, immune system enhancement, and with some other disorders or pharmacological effects. Beside the ortho-silicic acid and its stabilized formulations such as choline chloride-stabilized ortho-silicic acid and sodium or potassium silicates (e.g. M2SiO3; M= Na,K, the most important sources that release ortho-silicic acid as a bioavailable form of silicon are: colloidal silicic acid (hydrated silica gel, silica gel (amorphous silicon dioxide, and zeolites. Although all these compounds are characterized by substantial water insolubility, they release small, but significant, equilibrium concentration of ortho-silicic acid (H4SiO4 in contact with water and physiological fluids. Even though certain pharmacological effects of these compounds might be attributed to specific structural characteristics that result in profound adsorption and absorption properties, they all exhibit similar pharmacological profiles readily comparable to ortho-silicic acid effects. The most unusual ortho-silicic acid-releasing agents are certain types of zeolites, a class of aluminosilicates with well described ion(cation-exchange properties. Numerous biological activities of some types of zeolites documented so far might probably be attributable to the ortho-silicic acid-releasing property. In this review, we therefore discuss biological and potential therapeutic effects of ortho-silicic acid and ortho-silicic acid -releasing silicon compounds as its major natural sources.

  9. Synthesis of Luminescent Ink from Europium-Doped Y2O3 Dispersed in Polyvinyl Alcohol Solution

    Directory of Open Access Journals (Sweden)

    Astuti

    2009-01-01

    Full Text Available Luminescent ink from europium-doped Y2O3 ( Y2O3:Eu has been synthesized by two steps method: first, synthesis of luminescent powder of Y2O3:Eu by simple heating of metallic nitrates in a polymer solution and second, dispersing the powder in a polyvinyl alcohol (PVA solution. The stability of the ink (luminescent colloid was strongly affected by mixing process of the powder and the solution. Mixing process must be performed for a long time (about 8 hours at above room temperature to product stable colloids. We observed that mixing at 30–40∘C resulted in a stable and highly dispersed colloid. The writing test was performed on a white paper to show the potential use of the colloid for making security codes.

  10. Induced europium CPL for the selective signalling of phosphorylated amino-acids and O-phosphorylated hexapeptides.

    Science.gov (United States)

    Neil, Emily R; Fox, Mark A; Pal, Robert; Parker, David

    2016-05-17

    Two bright, europium(iii) complexes based on an achiral heptadentate triazacyclononane ligand bearing two strongly absorbing chromophores have been evaluated for the selective emission and CPL signalling of various chiral O-phosphono-anions. Binding of O-phosphono-Ser and Thr gives rise to a strong induced CPL signature and a favoured Δ complex configuration is adopted. A similarly large induced CPL signal arises when [Eu·](2+) binds to lysophosphatidic acid (LPA), where the strong binding (log K 5.25 (295 K)) in methanol allowed its detection over the range 5 to 40 μM. Strong and chemoselective binding to the phosphorylated amino-acid residues was also observed with a set of four structurally related hexapeptides: in one case, the sign of the gem value in the ΔJ = 1 transition allowed differentiation between the binding to O-P-Ser and O-P-Tyr residues.

  11. Modeling the viscosity of silicate melts containing manganese oxide

    Directory of Open Access Journals (Sweden)

    Kim Wan-Yi

    2013-01-01

    Full Text Available Our recently developed model for the viscosity of silicate melts is applied to describe and predict the viscosities of oxide melts containing manganese oxide. The model requires three pairs of adjustable parameters that describe the viscosities in three systems: pure MnO, MnO-SiO2 and MnO-Al2O3-SiO2. The viscosity of other ternary and multicomponent silicate melts containing MnO is then predicted by the model without any additional adjustable model parameters. Experimental viscosity data are reviewed for melts formed by MnO with SiO2, Al2O3, CaO, MgO, PbO, Na2O and K2O. The deviation of the available experimental data from the viscosities predicted by the model is shown to be within experimental error limits.

  12. Thermochemistry of Rare Earth Silicates for Environmental Barrier Coatings

    Science.gov (United States)

    Costa, Gustavo; Jacobson, Nathan

    2015-01-01

    Rare earth silicates are promising candidates as environmental protective coatings (EBCs) for silica-forming ceramics and composites in combustion environments since they are predicted to have lower reactivity with the water vapor combustion products. The reactivity of rare earth silicates is assessed by the thermodynamic activity of the silica component which is best measured by Knudsen effusion mass spectrometry (KEMS). Here, we discuss a novel method based on a reducing agent to increase the partial pressure of SiO(g) which is then used to calculate thermodynamic activity of silica in Y2O3-SiO2 and Yb2O3-SiO2 systems. After the KEMS measurements, samples were probed by X-ray diffraction and their phase content was calculated from Rietveld refinement.

  13. The viscosity window of the silicate glass foam production

    DEFF Research Database (Denmark)

    Petersen, Rasmus Rosenlund; König, Jakob; Yue, Yuanzheng

    2017-01-01

    The production of silicate glass foam allows diverse resources and waste materials to be used in the production. Testing of such large palette of materials complicates and prolongs the optimisation process. Therefore, it is crucial to find a universal criterion for foaming silicate glass melts...... which can offer a practical starting point for the optimisation procedure. The melt viscosity might be the most important parameter for controlling the foaming process and the glass foam density. In this work, we attempt to define a viscosity range in which foaming of different glasses results...... in a maximum of foam expansion. The expansion maximum is obtained for different glasses (labware, E-glass, CRT panel, soda-lime-silica) by foaming with CaCO3 at isokom temperature and from literature data. In general, the viscosity window was found to be within 104–106 Pa s when foaming with MnO2 or metal...

  14. Participation of bacteria in weathering processes of silicates

    Directory of Open Access Journals (Sweden)

    Peter Javorský

    2005-11-01

    Full Text Available Biological processes presented by the metabolic activity of different species of bacteria adhered at the mineral surfaces are a part of the geochemical processes. These bacteria accelerate, by the production of organic acids into the minerals structural bonds, the leaching of elements and their subsequent and gradual transformation to the secondary minerals. Microbial destructions of silicates are studied in order to processing low-quality mineral raw-materials and the remediation of soils, sediments and waters contaminated by industrial pollutants. The samples of material, used in our research, were obtained at 9 deposits of non-metallic raw-materials in Slovakia. The sediment sample was taken from the area of Baikal Lake. The presence of microorganisms in the matrix most frequently was determined by a subsequent isolation of microorganisms and identification of bacterial species presented in the silicate matrix. The species of Bacillus and Pseudomonas genus were the common representative of the microorganisms.

  15. Enzyme-Mimicking properties of silicates and other minerals

    Science.gov (United States)

    Siegel, B. Z.; Siegel, S. M.

    The adsorptive and/or catalytic properties of clays, silicates in general, and other minerals are well known. More recently, their probable role in prebiotic syntheses of bio-organic compounds has become a matter of record. We demonstrate that, in addition to their role in de novo formation of important biomolecules, clays, micas, fibrous silicates and other minerals mimick the activities of contemporary enzymes including oxidases, esterases, phosphatases and glucosidases. The existence of such capabilities in substances likely to be represented on the surfaces of Earth-like planets may offer a challenge to the technology and design of remote life detection systems which must then distinguish between bona fide biological chemistry and mineral-base pseudometabolism. It also raises questions about the importance of mineral surfaces in post-mortem transformations of organic metabolites in our own biosphere.

  16. The solubility of gold in silicate melts: First results

    Science.gov (United States)

    Borisov, A.; Palme, H.; Spettel, B.

    1993-01-01

    The effects of oxygen fugacity and temperature on the solubility of Au in silicate melts were determined. Pd-Au alloys were equilibrated with silicate of anorthite-diopside eutectic composition at different T-fO2 conditions. The behavior of Au was found to be similar to that of Pd reported recently. Au solubilities for alloys with 30 to 40 at. percent Au decrease at 1400 C from 12 ppm in air to 160 ppb at a log fO2 = -8.7. The slope of the log(Me-solubility) vs. log(fO2) curve is close to 1/4 for Au and the simultaneously determined Pd suggesting a formal valence of Au and Pd of 1+. Near the IW buffer Pd and Au solubilities become even less dependent on fO2 perhaps reflecting the presence of some metallic Au and Pd.

  17. A new europium(III)-β-diketonate complex based on diphenylethyne as red phosphors applied in LED

    Energy Technology Data Exchange (ETDEWEB)

    Shao, Guang, E-mail: shaog@mail.sysu.edu.cn [School of Chemistry and Chemical Engineering, Sun Yat-sen University, Guangzhou 510275 (China); Zhang, Na; Lin, Duan [School of Chemistry and Chemical Engineering, Sun Yat-sen University, Guangzhou 510275 (China); Feng, Kenjun [Department of Chemical Engineering, Hui-Zhou University, Huizhou 516007 (China); Cao, Rihui, E-mail: caorihui@mail.sysu.edu.cn [School of Chemistry and Chemical Engineering, Sun Yat-sen University, Guangzhou 510275 (China); Gong, Menglian [School of Chemistry and Chemical Engineering, Sun Yat-sen University, Guangzhou 510275 (China)

    2013-06-15

    A new europium(III) ternary complex based on a fluorinated β-diketonate ligand and 1,10-phenanthroline as an ancillary ligand has been prepared and evaluated as a candidate for light-emitting diode (LED). The complex exhibits a high decomposition temperature (316 °C). Photophysical properties such as FT-IR spectra, UV–vis absorption spectra, excitation and emission spectra, luminescence decay curve and quantum yield were investigated. The excitation band is well matched with the characteristic emission of 395 nm-emitting InGaN chips. The complex exhibits an efficient energy transfer pathway from the ligands to the central Eu{sup 3+} ion via a ligand-sensitized luminescence process. An intense red-emitting LED was fabricated by coating the complex onto a 395 nm-emitting InGaN chip, and its Commission International de I'Eclairage (CIE) chromaticity coordinate (x=0.6389, y=0.3255) is close to the National Television Standard Committee (NTSC) standard value for red color. Meanwhile, the energy transfer from the InGaN chip to the complex is very efficient. All the findings demonstrate the potential application of the Eu(III) complex as red-emitting phosphors for UV-based white LEDs. -- Highlights: ► A new europium(III)-β-diketonate complex was synthesized and characterized. ► Thermal stability and photophysical properties were investigated in detail. ► PL mechanism was proposed to involve a ligand-sensitized luminescence process. ► An intense red-emitting LED was fabricated by using the complex. ► CIE chromaticity coordinate is close to NTSC standard value for red color.

  18. Mitochondria Targetable Time-Gated Luminescence Probe for Singlet Oxygen Based on a β-Diketonate-Europium Complex.

    Science.gov (United States)

    Sun, Jingyan; Song, Bo; Ye, Zhiqiang; Yuan, Jingli

    2015-12-21

    Singlet oxygen ((1)O2) plays a key role in the photodynamic therapy (PDT) technique of neoplastic diseases. In this work, by using a 9,10-dimethyl-2-anthryl-containing β-diketone, 1,1,1,2,2-pentafluoro-5-(9',10'-dimethyl-2'-anthryl)-3,5-pentanedione (Hpfdap), as a (1)O2-recognition ligand, a novel β-diketonate-europium(III) complex that can act as a luminescence probe for (1)O2, [Eu(pfdap)3(tpy)] (tpy = 2,2',2″-terpyridine), has been designed and synthesized for the time-gated luminescence detection of (1)O2 in living cells. The complex is weakly luminescent due to the quenching effect of 9,10-dimethyl-2-anthryl groups. After reaction with (1)O2, accompanied by the formation of endoperoxides of 9,10-dimethyl-2-anthryl groups, the luminescence quenching disappears, so that the long-lived luminescence of the europium(III) complex is switched on. The complex showed highly selective luminescence response to (1)O2 with a remarkable luminescence enhancement. Combined with the time-gated luminescence imaging technique, the complex was successfully used as a luminescent probe for the monitoring of the time-dependent generation of (1)O2 in 5-aminolevulinic acid (a PDT drug) loaded HepG2 cells during the photodynamic process. In addition, by coloading the complex and a mitochondrial indicator, Mito-Tracker Green, into HepG2 cells, the specific localization of [Eu(pfdap)3(tpy)] molecules in mitochondria of HepG2 cells was demonstrated by confocal fluorescence imaging measurements.

  19. Conductivity studies of lithium zinc silicate glasses with varying ...

    Indian Academy of Sciences (India)

    WINTEC

    biomedical applications (McMillan 1979). The lithium– zinc–silicate (LZS) glass containing Li2O–ZnO–SiO2–. Na2O–B2O3–P2O5 has been used as the base glass for producing glass ceramics that are suitable for applications in hermetic glass–ceramic–to–metal seals with a variety of metals and alloys (Sharma et al 2004) ...

  20. Cracking phenomena in lithium-di-silicate glass ceramics

    Indian Academy of Sciences (India)

    Unknown

    Abstract. Lithium-di-silicate glass ceramic (Li2O, SiO2) with uniformly oriented crystals was placed on a. Vickers indentation with extrusion axis horizontally parallel to the base axis. The material was rotated through. 0°– 90° and at each angle a 20 N load was applied to ascertain the crack path. It was observed that the crack.

  1. Cracking phenomena in lithium-di-silicate glass ceramics

    Indian Academy of Sciences (India)

    Lithium-di-silicate glass ceramic (Li2O, SiO2) with uniformly oriented crystals was placed on a Vickers indentation with extrusion axis horizontally parallel to the base axis. The material was rotated through 0°– 90° and at each angle a 20 N load was applied to ascertain the crack path. It was observed that the crack length ...

  2. Apatite: a new redox proxy for silicic magmas?

    OpenAIRE

    Miles, A.J.; Graham, C M; Hawkesworth, C.J.; Gillespie, M.R.; Hinton, R.W.; Bromiley, G.D.

    2014-01-01

    The oxidation states of magmas provide valuable information about the release and speciation of volatile elements during volcanic eruptions, metallogenesis, source rock compositions, open system magmatic processes, tectonic settings and potentially titanium (Ti) activity in chemical systems used for Ti-dependent geothermometers and geobarometers. In this paper we explore the use of Mn in apatite as an oxybarometer in intermediate and silicic igneous rocks. Increased Mn concentrations in apati...

  3. INORGANIC PHOSPHORS IN GLASS BASED ON LEAD SILICATE GLASSES

    Directory of Open Access Journals (Sweden)

    V. A. Aseev

    2014-09-01

    Full Text Available We created and synthesized luminescent composite of the "phosphor in glass" type, based on the lead-silicate matrix and fine-dispersed powder of cerium-activated yttrium-aluminum garnet crystal. Lead-silicate system (40SiO2- 20PbO-(40-x PbF2-xAlF3, x = 0-25 was chosen as the glassy matrix. Initial glass was reduced to powder (frit for "phosphor in glass" composite with a particle size about 50 µm. Glass frit and powder of commercial YAG:Ce3+ phosphor were mixed in a ratio of 30 to 70 (wt %. Then this composite was pressed in a tablet and sintered on a quartz substrate at 823 К for 30 minutes. Thus, the plane parallel sheet for composite of the "phosphor in glass" was obtained with a diameter equal to 10 mm. For the purpose to reduce the loss of light in the presence of dispersion at a glass-phosphor boundary, optimization of glass mixture was done by adjusting the refractive index. X-ray phase and spectral-luminescent analysis of the derived composite were done. The results of these studies showed that there was no degradation of YAG: Ce powder during sintering. Dependence of luminescence intensity from temperature in the range from room temperature to 473 К was studied. It was shown, that with the phosphor in glass usage thermal quenching of luminescence was reduced in comparison with the silicone. The model of white LED was created with the "phosphor in glass" composite based on lead-silicate glasses with low temperature of vitrifying. The derived LED emits white light with a color temperature of 4370 K, and the luminous efficiency is equal to 58 lm/W. The developed luminescent composite based on the lead-silicate matrix can be used for the production of high-power white light LED.

  4. Soda-Lime-Silicate Float Glass: A Property Comparison

    Science.gov (United States)

    2017-10-01

    Laboratory Soda-Lime-Silicate Float Glass: A Property Comparison by Andrew Cachiaras Science and Mathematics Academy at Aberdeen High School...Aberdeen, MD Luke Gilde Oak Ridge Institute for Science and Education, Oak Ridge, TN George D Quinn National Institute of Standards and...transparent armor systems. Thus, it is necessary to measure and compare the chemical composition as well as the physical and mechanical properties of

  5. Cleavage Energies of Modified Layered Silicates by Molecular Dynamics Simulation

    Science.gov (United States)

    Fu, Yao-Tsung; Heinz, Hendrik

    2009-03-01

    The cleavage energy of organically modified layered silicates indicates the thermodynamic propensity of exfoliation in polymer matrices. We find substantial cleavage energy differences upon variation in cation exchange capacity (CEC) (90 and 145 meq/100g), head groups (-NH3 and --NMe3), and chain length of the surfactants (C2 to C14) due to layering effects of the surfactants in the galleries using molecular dynamics simulation. Model systems of full atomistic detail are periodic in the xy plane, open in the z direction, are subjected to sheet separation starting at equilibrium distance. Overall, the cleavage energy, consistent with experimentally measured surface tensions and previous calculations for selected organoclays, shows complex fluctuations as a function of chain length and head group structure. Computed cleavage energies are in the range 25-50 mJ/m^2 for C2˜C14 (-NH3 headgroup) and 40-200 mJ/m^2 for C2˜C14 (--NMe3 headgroup) at two CEC layered silicates. The progression is not linear and related to the packing density of the interlayer of self-assembled surfactant chains and surface reconstruction of the modified layered silicates upon cleavage.

  6. Silicate dissolution boosts the CO2 concentrations in subduction fluids.

    Science.gov (United States)

    Tumiati, S; Tiraboschi, C; Sverjensky, D A; Pettke, T; Recchia, S; Ulmer, P; Miozzi, F; Poli, S

    2017-09-20

    Estimates of dissolved CO2 in subduction-zone fluids are based on thermodynamic models, relying on a very sparse experimental data base. Here, we present experimental data at 1-3 GPa, 800 °C, and ∆FMQ ≈ -0.5 for the volatiles and solute contents of graphite-saturated fluids in the systems COH, SiO2-COH ( + quartz/coesite) and MgO-SiO2-COH ( + forsterite and enstatite). The CO2 content of fluids interacting with silicates exceeds the amounts measured in the pure COH system by up to 30 mol%, as a consequence of a decrease in water activity probably associated with the formation of organic complexes containing Si-O-C and Si-O-Mg bonds. The interaction of deep aqueous fluids with silicates is a novel mechanism for controlling the composition of subduction COH fluids, promoting the deep CO2 transfer from the slab-mantle interface to the overlying mantle wedge, in particular where fluids are stable over melts.Current estimates of dissolved CO2 in subduction-zone fluids based on thermodynamic models rely on a very sparse experimental data base. Here, the authors show that experimental graphite-saturated COH fluids interacting with silicates at 1-3 GPa and 800 °C display unpredictably high CO2 contents.

  7. A Review: Fundamental Aspects of Silicate Mesoporous Materials

    Directory of Open Access Journals (Sweden)

    Zeid A. ALOthman

    2012-12-01

    Full Text Available Silicate mesoporous materials have received widespread interest because of their potential applications as supports for catalysis, separation, selective adsorption, novel functional materials, and use as hosts to confine guest molecules, due to their extremely high surface areas combined with large and uniform pore sizes. Over time a constant demand has developed for larger pores with well-defined pore structures. Silicate materials, with well-defined pore sizes of about 2.0–10.0 nm, surpass the pore-size constraint (<2.0 nm of microporous zeolites. They also possess extremely high surface areas (>700 m2 g−1 and narrow pore size distributions. Instead of using small organic molecules as templating compounds, as in the case of zeolites, long chain surfactant molecules were employed as the structure-directing agent during the synthesis of these highly ordered materials. The structure, composition, and pore size of these materials can be tailored during synthesis by variation of the reactant stoichiometry, the nature of the surfactant molecule, the auxiliary chemicals, the reaction conditions, or by post-synthesis functionalization techniques. This review focuses mainly on a concise overview of silicate mesoporous materials together with their applications. Perusal of the review will enable researchers to obtain succinct information about microporous and mesoporous materials.

  8. Development of Li+ alumino-silicate ion source

    Energy Technology Data Exchange (ETDEWEB)

    Roy, P.K.; Seidl, P.A.; Waldron, W.; Greenway, W.; Lidia, S.; Anders, A.; Kwan, J.

    2009-04-21

    To uniformly heat targets to electron-volt temperatures for the study of warm dense matter, one strategy is to deposit most of the ion energy at the peak of energy loss (dE/dx) with a low (E< 5 MeV) kinetic energy beam and a thin target[1]. Lower mass ions have a peak dE/dx at a lower kinetic energy. To this end, a small lithium (Li+) alumino-silicate source has been fabricated, and its emission limit has been measured. These surface ionization sources are heated to 1000-1150 C where they preferentially emit singly ionized alkali ions. Alumino-silicates sources of K+ and Cs+ have been used extensively in beam experiments, but there are additional challenges for the preparation of high-quality Li+ sources: There are tighter tolerances in preparing and sintering the alumino-silicate to the substrate to produce an emitter that gives uniform ion emission, sufficient current density and low beam emittance. We report on recent measurements ofhigh ( up to 35 mA/cm2) current density from a Li+ source. Ion species identification of possible contaminants is being verified with a Wien (E x B) filter, and via time-of-flight.

  9. Investigation of synthesized Be-bearing silicate glass as laboratory reference sample at X-ray electron probe microanalysis of silicates

    Science.gov (United States)

    Belozerova, Olga Yu.; Mikhailov, Mikhail A.; Demina, Tamara V.

    2017-01-01

    The article discusses estimates of the stability and homogeneity in Be-Mg-Al-silicate glass produced by the authors and its applicability as a laboratory reference sample for X-ray electron probe microanalysis (EPMA) of Be-bearing silicate matters: crystals and quenching melt (glasses), silicates and oxides. The results were obtained using Superprobe-733 and Superprobe JXA-8200 (JEOL Ltd, Japan) devices. The sample homogeneity was studied on macro (10-100 μm) and micro (1-10 μm) levels and was evaluated by the scheme of dispersion analysis. The applicability of Be-bearing silicate glass as a reference sample for Mg, Al, Si determinations was tested on the international certified reference glasses and laboratory reference samples of minerals with a known composition. The obtained experimental metrological characteristics correspond to the "applied geochemistry" type of analysis (second category) and suggest that Be-bearing silicate glass is appropriate as a laboratory reference sample for EPMA of Be-bearing silicate matters, silicates and oxides. Using Be-Mg-Al-silicate glass as a reference sample we obtained satisfactory data on the composition of both some minerals including cordierite and beryllium cordierite, beryllium indialite, beryl and metastable phases (chrysoberyl, compounds with structure of β-quartz and petalite).

  10. Excitation energy transfer in europium chelate with doxycycline in the presence of a second ligand in micellar solutions of nonionic surfactants

    Science.gov (United States)

    Smirnova, T. D.; Shtykov, S. N.; Kochubei, V. I.; Khryachkova, E. S.

    2011-01-01

    The complexation of Eu3+ with doxycycline (DC) antibiotic in the presence of several second ligands and surfactant micelles of different types is studied by the spectrophotometric and luminescence methods. It is found that the efficiency of excitation energy transfer in Eu3+-DC chelate depends on the nature of the second ligand and surfactant micelles. Using thenoyltrifluoroacetone (TTA) as an example, it is shown that the second ligand additionally sensitizes the europium fluorescence, and the possibility of intermediate sensitization of DC and then of europium is shown by the example of 1,10-phenanthroline. In all cases, the excitation energy transfer efficiency was increased due to the so-called antenna effect. The decay kinetics of the sensitized fluorescence of the binary and mixed-ligand chelates in aqueous and micellar solutions of nonionic surfactants is studied and the relative quantum yields and lifetimes of fluorescence are determined.

  11. A Smart Europium-Ruthenium Complex as Anticancer Prodrug: Controllable Drug Release and Real-Time Monitoring under Different Light Excitations.

    Science.gov (United States)

    Li, Hongguang; Xie, Chen; Lan, Rongfeng; Zha, Shuai; Chan, Chi-Fai; Wong, Wing-Yan; Ho, Ka-Lok; Chan, Brandon Dow; Luo, Yuxia; Zhang, Jing-Xiang; Law, Ga-Lai; Tai, William C S; Bünzli, Jean-Claude G; Wong, Ka-Leung

    2017-11-09

    A unique, dual-function, photoactivatable anticancer prodrug, RuEuL, has been tailored that features a ruthenium(II) complex linked to a cyclen-europium chelate via a π-conjugated bridge. Under irradiation at 488 nm, the dark-inactive prodrug undergoes photodissociation, releasing the DNA-damaging ruthenium species. Under evaluation-window irradiation (λirr = one-photon 350 nm or two-photon 700 nm), the drug delivery process can be quantitatively monitored in real-time because of the long-lived red europium emission. Linear relationships between released drug concentration and ESI-MS or luminescence responses are established. Finally, the efficiency of the new prodrug is demonstrated both in vitro RuEuL anticancer prodrug over some existing ones and open the way for decisive improvements in multipurpose prodrugs.

  12. Confined Water in Layered Silicates: The Origin of Anomalous Thermal Expansion Behavior in Calcium-Silicate-Hydrates.

    Science.gov (United States)

    Krishnan, N M Anoop; Wang, Bu; Falzone, Gabriel; Le Pape, Yann; Neithalath, Narayanan; Pilon, Laurent; Bauchy, Mathieu; Sant, Gaurav

    2016-12-28

    Water, under conditions of nanoscale confinement, exhibits anomalous dynamics, and enhanced thermal deformations, which may be further enhanced when such water is in contact with hydrophilic surfaces. Such heightened thermal deformations of water could control the volume stability of hydrated materials containing nanoconfined structural water. Understanding and predicting the thermal deformation coefficient (TDC, often referred to as the CTE, coefficient of thermal expansion), which represents volume changes induced in materials under conditions of changing temperature, is of critical importance for hydrated solids including: hydrogels, biological tissues, and calcium silicate hydrates, as changes in their volume can result in stress development, and cracking. By pioneering atomistic simulations, we examine the physical origin of thermal expansion in calcium-silicate-hydrates (C-S-H), the binding agent in concrete that is formed by the reaction of cement with water. We report that the TDC of C-S-H shows a sudden increase when the CaO/SiO2 (molar ratio; abbreviated as Ca/Si) exceeds 1.5. This anomalous behavior arises from a notable increase in the confinement of water contained in the C-S-H's nanostructure. We identify that confinement is dictated by the topology of the C-S-H's atomic network. Taken together, the results suggest that thermal deformations of hydrated silicates can be altered by inducing compositional changes, which in turn alter the atomic topology and the resultant volume stability of the solids.

  13. Structural and optical analysis on europium doped AZrO{sub 3} (A=Ba, Ca, Sr) phosphor for display devices application

    Energy Technology Data Exchange (ETDEWEB)

    Dubey, Vikas, E-mail: jsvikasdubey@gmail.com [Department of Physics, Bhilai Institute of Technology Raipur, 493661 (India); Tiwari, Neha [Department of Physics, Govt. Model Science College, Jabalpur (India)

    2016-05-06

    Behavior displayed by europium doped AZrO{sub 3} phosphor which was synthesized by solid state reaction method. For synthesis of BaZrO{sub 3}, SrZrO{sub 3} and CaZrO{sub 3} phosphor with fixed concentration of europium ion was calcination at 1000°C and sintered at 1300°C following intermediate grinding. Synthesized sample was characterized by X-ray diffraction analysis and crystallite sized was calculated by Scherer’s formula. From PL spectra of prepared phosphors shows intense emission centred at 612nm (red emission) with high intensity for SrZrO{sub 3}:Eu{sup 3+}. For europium doped BaZrO{sub 3} and CaZrO{sub 3} (613nm) phosphor shows less intense PL spectra as compared to SrZrO{sub 3}:Eu{sup 3+}. The strong emission peak of AZrO{sub 3}:Eu{sup 3+} phosphor is due to forced electric dipole transition of {sup 5}D{sub 0} to {sup 7}F{sub 2} centered at 612 and 613nm. It is characteristic red emission for europium ion. The excitation spectra of AZrO{sub 3}:Eu{sup 3+} phosphor mainly consists of the charge transfer and (CTB) of Eu{sup 3+} located in 200–350 nm centred at 254nm. The present phosphors can act as single host for red light emission in display devices. The CIE coordinates were calculated by Spectrophotometric method using the spectral energy distribution of the AZrO{sub 3}:Eu{sup 3+} sample.

  14. Metal-organic framework luminescence in the yellow gap by codoping of the homoleptic imidazolate ∞(3)[Ba(Im)2] with divalent europium.

    Science.gov (United States)

    Rybak, Jens-Christoph; Hailmann, Michael; Matthes, Philipp R; Zurawski, Alexander; Nitsch, Jörn; Steffen, Andreas; Heck, Joachim G; Feldmann, Claus; Götzendörfer, Stefan; Meinhardt, Jürgen; Sextl, Gerhard; Kohlmann, Holger; Sedlmaier, Stefan J; Schnick, Wolfgang; Müller-Buschbaum, Klaus

    2013-05-08

    The rare case of a metal-triggered broad-band yellow emitter among inorganic-organic hybrid materials was achieved by in situ codoping of the novel imidazolate metal-organic framework ∞(3)[Ba(Im)2] with divalent europium. The emission maximum of this dense framework is in the center of the yellow gap of primary light-emitting diode phosphors. Up to 20% Eu2+ can be added to replace Ba2+ as connectivity centers without causing observable phase segregation. High-resolution energy-dispersive X-ray spectroscopy showed that incorporation of even 30% Eu2+ is possible on an atomic level, with 2-10% Eu2+ giving the peak quantum efficiency (QE = 0.32). The yellow emission can be triggered by two processes: direct excitation of Eu2+ and an antenna effect of the imidazolate linkers. The emission is fully europium-centered, involving 5d → 4f transitions, and depends on the imidazolate surroundings of the metal ions. The framework can be obtained by a solvent-free in situ approach starting from barium metal, europium metal, and a melt of imidazole in a redox reaction. Better homogeneity for the distribution of the luminescence centers was achieved by utilizing the hydrides BaH2 and EuH2 instead of the metals.

  15. α-Titanium phosphate intercalated with propylamine: An alternative pathway for efficient europium(III uptake into layered tetravalent metal phosphates

    Directory of Open Access Journals (Sweden)

    Jorge García-Glez

    2017-09-01

    Full Text Available α-Ti(HPO42·H2O (α-TiP and its propylamine intercalation product, Ti(HPO42·2C3H7NH2·H2O (α-TiPPr, have been synthesized and characterized. Later, their sorption capacity for europium(III was investigated, and this purpose was accomplished by treating α-TiP and α-TiPPr with europium(III nitrate solutions at different concentrations until the equilibrium is reached. All samples were characterized, among others, by powder X-ray diffraction (PXRD, scanning and transmission electron microscopies (SEM, TEM, STEM-EDX, SAED, thermogravimetric analysis (TGA, and photoluminescence (PL measurements. The results show that the Eu3+ uptake is limited to surface when α-TiP is used as sorbent. Nevertheless, the Eu-retention is considerably enhanced with α-TiPPr as a consequence of an ion-exchange process into the interlayer space of the layered titanium phosphate (involving propylammonium cations, C3H7NH3+, and hexahydrate europium(III species, [Eu(H2O6]3+, and the crystal structure of a hypothetical final product, α-[Eu(H2O6]2/3Ti(PO42·[(H2O6]1/3, has been proposed by using DFT calculations.

  16. Microstructure engineering of Portland cement pastes and mortars through addition of ultrafine layer silicates

    DEFF Research Database (Denmark)

    Lindgreen, Holger; Geiker, Mette Rica; Krøyer, Hanne

    2008-01-01

    Pozzolanic submicron-sized silica fume and the non-pozzolanic micron- and nano-sized layer silicates (clay minerals) kaolinite, smectite and palygorskite have been used as additives in Portland cement pastes and mortars. These layer silicates have different particle shape (needles and plates...... is that the cement paste structure and porosity can be engineered by addition of selected layer silicates having specific particle shapes and surface properties (e.g., charge and specific surface area). This seems to be due to the growth of calcium-silicate hydrates (C-S-H) on the clay particle surfaces......, and the nano-structure of the C-S-H depends on type of layer silicate. The effect of layer silicate addition is most pronounced for palygorskite and smectite having the largest surface area and negative charges on the particle surfaces. The cement pastes containing palygorskite and bentonite have...

  17. Pyrolytic Synthesis of Carbon Nanotubes from Sucrose on a Mesoporous Silicate

    Science.gov (United States)

    Abdel-Fattah, Tarek; Siochi, Mia; Crooks, Roy

    2005-01-01

    Multiwall carbon nanotubes were synthesized from sucrose by a pyrolytic technique using mesoporous MCM-41 silicate templates without transition metal catalysts. The Nanotubes were examined in the carbon/silicate composite and after dissolution of the silicate. High resolution transmission electron microscopy study of the multiwall nanotubes showed them to be 15 nm in diameter, 200 nm in length and close-ended. There was variation in crystallinity with some nanotubes showing disordered wall structures.

  18. Proton tunneling in low dimensional cesium silicate LDS-1

    Energy Technology Data Exchange (ETDEWEB)

    Matsui, Hiroshi, E-mail: matsui-ldp@m.tohoku.ac.jp; Iwamoto, Kei [Department of Physics, Graduate School of Science, Tohoku University, Sendai 980-8578 (Japan); Mochizuki, Dai [Interdisciplinary Cluster for Cutting Edge Research, Center for Energy and Environmental Science, Shinshu University, 3-15-1 Tokida, Ueda, Nagano 386-8567 (Japan); Osada, Shimon; Asakura, Yusuke [Department of Applied Chemistry, Faculty of Science and Engineering, Waseda University, Tokyo 169-8555 (Japan); Kuroda, Kazuyuki [Department of Applied Chemistry, Faculty of Science and Engineering, Waseda University, Tokyo 169-8555 (Japan); Kagami Memorial Research Institute for Material Science and Technology, Waseda University, Tokyo 169-0051 (Japan)

    2015-07-14

    In low dimensional cesium silicate LDS-1 (monoclinic phase of CsHSi{sub 2}O{sub 5}), anomalous infrared absorption bands observed at 93, 155, 1210, and 1220 cm{sup −1} are assigned to the vibrational mode of protons, which contribute to the strong hydrogen bonding between terminal oxygen atoms of silicate chain (O–O distance = 2.45 Å). The integrated absorbance (oscillator strength) for those modes is drastically enhanced at low temperatures. The analysis of integrated absorbance employing two different anharmonic double-minimum potentials makes clear that proton tunneling through the potential barrier yields an energy splitting of the ground state. The absorption bands at 93 and 155 cm{sup −1}, which correspond to the different vibrational modes of protons, are attributed to the optical transition between the splitting levels (excitation from the ground state (n = 0) to the first excited state (n = 1)). Moreover, the absorption bands at 1210 and 1220 cm{sup −1} are identified as the optical transition from the ground state (n = 0) to the third excited state (n = 3). Weak Coulomb interactions in between the adjacent protons generate two types of vibrational modes: symmetric mode (93 and 1210 cm{sup −1}) and asymmetric mode (155 and 1220 cm{sup −1}). The broad absorption at 100–600 cm{sup −1} reveals an emergence of collective mode due to the vibration of silicate chain coupled not only with the local oscillation of Cs{sup +} but also with the proton oscillation relevant to the second excited state (n = 2)

  19. SILICATES ON IAPETUS FROM CASSINI’S COMPOSITE INFRARED SPECTROMETER

    Energy Technology Data Exchange (ETDEWEB)

    Young, Cindy L.; Wray, James J. [School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA (United States); Clark, Roger N. [Planetary Science Institute, Tucson, AZ (United States); Spencer, John R. [Southwest Research Institute, Boulder, CO (United States); Jennings, Donald E. [NASA Goddard Space Flight Center, Greenbelt, MD (United States); Hand, Kevin P.; Carlson, Robert W. [Jet Propulsion Laboratory, Pasadena, CA (United States); Poston, Michael J. [Caltech, Pasadena, CA (United States)

    2015-10-01

    We present the first spectral features obtained from Cassini’s Composite Infrared Spectrometer (CIRS) for any icy moon. The spectral region covered by CIRS focal planes (FP) 3 and 4 is rich in emissivity features, but previous studies at these wavelengths have been limited by low signal-to-noise ratios (S/Ns) for individual spectra. Our approach is to average CIRS FP3 spectra to increase the S/N and use emissivity spectra to constrain the composition of the dark material on Iapetus. We find an emissivity feature at ∼855 cm{sup −1} and a possible doublet at 660 and 690 cm{sup −1} that do not correspond to any known instrument artifacts. We attribute the 855 cm{sup −1} feature to fine-grained silicates, similar to those found in dust on Mars and in meteorites, which are nearly featureless at shorter wavelengths. Silicates on the dark terrains of Saturn’s icy moons have been suspected for decades, but there have been no definitive detections until now. Serpentines reported in the literature at ambient temperature and pressure have features near 855 and 660 cm{sup −1}. However, peaks can shift depending on temperature and pressure, so measurements at Iapetus-like conditions are necessary for more positive feature identifications. As a first investigation, we measured muscovite at 125 K in a vacuum and found that this spectrum does match the emissivity feature near 855 cm{sup −1} and the location of the doublet. Further measurements are needed to robustly identify a specific silicate, which would provide clues regarding the origin and implications of the dark material.

  20. Light-cured Tricalcium Silicate Toxicity to the Dental Pulp.

    Science.gov (United States)

    Jeanneau, Charlotte; Laurent, Patrick; Rombouts, Charlotte; Giraud, Thomas; About, Imad

    2017-12-01

    Numerous studies reported dentin bridge formation after pulp capping with tricalcium silicates. By contrast, pulp capping with resins leads to pulp toxicity and inflammation. Hybrid materials made up of tricalcium silicates and resins have also been developed to be used in direct pulp capping. This work was designed to study the consequences of adding resins to tricalcium silicates by investigating TheraCal (BISCO, Lançon De Provence, France) and Biodentine (Septodont, Saint Maur des Fosses, France) interactions with the dental pulp. Media conditioned with the biomaterials were used to analyze pulp fibroblast proliferation using the MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide) test and proinflammatory cytokine interleukin 8 (IL-8) secretion using the enzyme-linked immunosorbent assay. The effects of conditioned media on dentin sialoprotein (DSP) and nestin expression by dental pulp stem cells (DPSCs) were investigated by immunofluorescence. The materials' interactions with the vital pulp were investigated using the entire tooth culture model. TheraCal-conditioned media significantly decreased pulp fibroblast proliferation, whereas no effect was observed with Biodentine. When DPSCs were cultured with Biodentine-conditioned media, immunofluorescence showed an increased expression of DSP and nestin. This expression was lower with TheraCal, which significantly induced proinflammatory IL-8 release both in cultured fibroblasts and entire tooth cultures. This IL-8 secretion increase was not observed with Biodentine. Entire tooth culture histology showed a higher mineralization with Biodentine, whereas significant tissue disorganization was observed with TheraCal. Within the limits of these preclinical results, resin-containing TheraCal cannot be recommended for direct pulp capping. Copyright © 2017 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  1. Low- 18O silicic magmas: why are they so rare?

    Science.gov (United States)

    Balsley, Steven D.; Gregory, Robert T.

    1998-10-01

    Low- 18O silicic magmas are reported from only a small number of localities (e.g., Yellowstone and Iceland), yet petrologic evidence points to upper crustal assimilation coupled with fractional crystallization (AFC) during magma genesis for nearly all silicic magmas. The rarity of low- 18O magmas in intracontinental caldera settings is remarkable given the evidence of intense low- 18O meteoric hydrothermal alteration in the subvolcanic remnants of larger caldera systems. In the Platoro caldera complex, regional ignimbrites (150-1000 km 3) have plagioclase δ 18O values of 6.8±0.1‰, whereas the Middle Tuff, a small-volume (est. 50-100 km 3) post-caldera collapse pyroclastic sequence, has plagioclase δ 18O values between 5.5 and 6.8‰. On average, the plagioclase phenocrysts from the Middle Tuff are depleted by only 0.3‰ relative to those in the regional tuffs. At Yellowstone, small-volume post-caldera collapse intracaldera rhyolites are up to 5.5‰ depleted relative to the regional ignimbrites. Two important differences between the Middle Tuff and the Yellowstone low- 18O rhyolites elucidate the problem. Middle Tuff magmas reached water saturation and erupted explosively, whereas most of the low- 18O Yellowstone rhyolites erupted effusively as domes or flows, and are nearly devoid of hydrous phenocrysts. Comparing the two eruptive types indicates that assimilation of low- 18O material, combined with fractional crystallization, drives silicic melts to water oversaturation. Water saturated magmas either erupt explosively or quench as subsurface porphyries before the magmatic 18O can be dramatically lowered. Partial melting of low- 18O subvolcanic rocks by near-anhydrous magmas at Yellowstone produced small-volume, low- 18O magmas directly, thereby circumventing the water saturation barrier encountered through normal AFC processes.

  2. Low-(18)O Silicic Magmas: Why Are They So Rare?

    Energy Technology Data Exchange (ETDEWEB)

    Balsley, S.D.; Gregory, R.T.

    1998-10-15

    LOW-180 silicic magmas are reported from only a small number of localities (e.g., Yellowstone and Iceland), yet petrologic evidence points to upper crustal assimilation coupled with fractional crystallization (AFC) during magma genesis for nearly all silicic magmas. The rarity of 10W-l `O magmas in intracontinental caldera settings is remarkable given the evidence of intense 10W-l*O meteoric hydrothermal alteration in the subvolcanic remnants of larger caldera systems. In the Platoro caldera complex, regional ignimbrites (150-1000 km3) have plagioclase 6180 values of 6.8 + 0.1%., whereas the Middle Tuff, a small-volume (est. 50-100 km3) post-caldera collapse pyroclastic sequence, has plagioclase 8]80 values between 5.5 and 6.8%o. On average, the plagioclase phenocrysts from the Middle Tuff are depleted by only 0.3%0 relative to those in the regional tuffs. At Yellowstone, small-volume post-caldera collapse intracaldera rhyolites are up to 5.5%o depleted relative to the regional ignimbrites. Two important differences between the Middle Tuff and the Yellowstone 10W-180 rhyolites elucidate the problem. Middle Tuff magmas reached water saturation and erupted explosively, whereas most of the 10W-l 80 Yellowstone rhyolites erupted effusively as domes or flows, and are nearly devoid of hydrous phenocrysts. Comparing the two eruptive types indicates that assimilation of 10W-180 material, combined with fractional crystallization, drives silicic melts to water oversaturation. Water saturated magmas either erupt explosively or quench as subsurface porphyrins bejiire the magmatic 180 can be dramatically lowered. Partial melting of low- 180 subvolcanic rocks by near-anhydrous magmas at Yellowstone produced small- volume, 10W-180 magmas directly, thereby circumventing the water saturation barrier encountered through normal AFC processes.

  3. Synthesis of magnesium silicate from wheat husk ash: Effects of parameters on structural and surface properties

    OpenAIRE

    Pinar Terzioglu; Sevil Yucel

    2012-01-01

    In the present study, magnesium silicate was produced by using wheat husk ash. Wheat husk was burned at 600 °C to obtain an amorphous ash structure, and the ash was processed with sodium hydroxide solution with heat to extract silica. Sodium silicate solution and magnesium salts were used to synthesize magnesium silicate. The present study investigates effects of the feeding rate on magnesium silicate production (0.6 mL/min, 35 mL/min, 70 mL/min), the type of magnesium salt (MgSO4 • 7H2O or M...

  4. Studies on Thermal Degradation Behavior of Siliceous Agriculture Waste (Rice Husk, Wheat Husk and Bagasse)

    National Research Council Canada - National Science Library

    Syed H. Javed; Umair Aslam; Mohsin Kazmi; Masooma Rustam; Sheema Riaz; Zahid Munir

    2015-01-01

    Various siliceous agriculture waste (SAW) such as rice husk, wheat husk and bagasse have been investigated to study their thermal degradation behavior using Thermogravimetric Analyzer (TGA) technique...

  5. High-temperature silicate volcanism on Jupiter's moon Io

    Science.gov (United States)

    McEwen, A.S.; Keszthelyi, L.; Spencer, J.R.; Schubert, G.; Matson, D.L.; Lopes-Gautier, R.; Klaasen, K.P.; Johnson, T.V.; Head, J.W.; Geissler, P.; Fagents, S.; Davies, A.G.; Carr, M.H.; Breneman, H.H.; Belton, M.J.S.

    1998-01-01

    Infrared wavelength observations of Io by the Galileo spacecraft show that at last 12 different vents are erupting lavas that are probably hotter than the highest temperature basaltic eruptions on Earth today. In at least one case, the eruption near Pillan Patea, two independent instruments on Galileo show that the lava temperature must have exceeded 1700 kelvin and may have reached 2000 kelvin. The most likely explanation is that these lavas are ultramafic (magnesium-rich) silicates, and this idea is supported by the tentative identification of magnesium-rich orthopyroxene in lava flows associated with thse high-temperature hot spots.

  6. Alkali-metal silicate binders and methods of manufacture

    Science.gov (United States)

    Schutt, J. B. (Inventor)

    1979-01-01

    A paint binder is described which uses a potassium or sodium silicate dispersion having a silicon dioxide to alkali-metal oxide mol ratio of from 4.8:1 to 6.0:1. The binder exhibits stability during both manufacture and storage. The process of making the binder is predictable and repeatable and the binder may be made with inexpensive components. The high mol ratio is achieved with the inclusion of a silicon dioxide hydrogel. The binder, which also employs a silicone, is in the final form of a hydrogel sol.

  7. Activity composition relationships in silicate melts. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Glazner, A.F.

    1990-12-31

    Equipment progress include furnace construction and electron microprobe installation. The following studies are underway: phase equilibria along basalt-rhyolite mixing line (olivine crystallization from natural silicic andensites, distribution of Fe and Mg between olivine and liquid, dist. of Ca and Na between plagioclase and liquid), enthalpy-composition relations in magmas (bulk heat capacity of alkali basalt), density model for magma ascent and contamination, thermobarometry in igneous systems (olivine/plagioclase phenocryst growth in Quat. basalt), high-pressure phase equilibria of alkali basalt, basalt-quartz mixing experiments, phase equilibria of East African basalts, and granitic minerals in mafic magma. (DLC)

  8. Calcium silicate hydrates: Solid and liquid phase composition

    OpenAIRE

    Lothenbach Barbara; Nonat André

    2015-01-01

    © 2015 Elsevier Ltd. This paper presents a review on the relationship between the composition the structure and the solution in which calcium silicate hydrate (C S H) is equilibrated. The silica chain length in C S H increases with the silicon concentration and the calcium content in the interlayer space with the calcium concentrations. Sodium and potassium are taken up in the interlayer space preferentially at low calcium concentrations and thus by low Ca/Si C S H. Aluminium uptake in C S H ...

  9. Space Weathering of Silicate Asteroids: An Observational Investigation

    Science.gov (United States)

    MacLennan, Eric M.; Emery, Joshua; Lindsay, Sean S.

    2017-10-01

    Solar wind exposure and micrometeoroid bombardment are known to cause mineralogical changes in the upper few microns of silicate grains (by forming amorphous “composition” rims with embedded nano-phase Fe0). These processes, jointly called space weathering (SW), affect the light-scattering properties and subsequently the geometric albedo and spectral parameters (spectral slope and band depth). Earth’s Moon exhibits the well known “lunar-style” of SW: albedo decrease, spectral slope increase, and absorption band suppression. However, space mission images of (243) Ida and (433) Eros suggest that different SW “styles” exist among the silicate-bearing (olivine and pyroxene) S-complex asteroids, which exhibit diagnostic absorption features near 1 & 2 μm. While Eros generally shows only albedo differences between younger and older locations, Ida’s surface only shows changes in spectral slope and band depth. It is not clear if these SW styles are unique to Ida and Eros or if they can be observed throughout the entire asteroid population.We hypothesize that the SW styles seen on Eros and Ida also exist on other asteroid surfaces. Additionally, we hypothesize that increased solar wind exposure, smaller regolith particles, higher olivine abundance, and older asteroid surfaces will increase the observed degree of SW. Our dataset includes publicly available Visible (0.4-0.8 μm) and Near Infrared (~0.7-2.5 μm) reflectance spectra of silicate-bearing asteroids (those with 1 & 2 μm bands) from the PDS and the SMASS, S3OS2 and MIT-UH-IRTF spectral surveys. We have also conducted a spectral survey with the IRTF/SpeX targeting 52 silicate asteroids for which we have constraints for regolith grain sizes from interpretation of thermal-IR data. The relevant band parameters to SW and to interpreting mineralogical properties are calculated using the band analysis code, SARA. Geometric albedos are calculated using thermal-IR data from WISE/NEOWISE. Using these derived

  10. Infrared spectroscopy and hydrogen isotope geochemistry of hydrous silicate glasses

    Energy Technology Data Exchange (ETDEWEB)

    Epstein, S.; Stolper, E.

    1992-01-01

    The focus of this project is the combined appication of infrared spectroscopy and stable isotope geochemistry to the study of hydrogen-bearing species dissolved in silicate melts and glasses. We are conducting laboratory experiments aimed at determining the fractionation of D and H between melt species (OH and H{sub 2}O) and hydrous vapor and the diffusivities of these species in glasses and melts. Knowledge of these parameters is critical to understanding the behavior of hydrogen isotopes during igneous processes and hydrothermal processes. These results also could be valuable in application of glass technology to development of nuclear waste disposal strategies.

  11. Tin in silicate glasses: structure, thermodynamics and kinetics

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Verena; Ksenofontov, Vadim [Johannes Gutenberg-Universitaet Mainz, Institut fuer Anorganische Chemie und Analytische Chemie (Germany); Aigner, Maria-Louisa; Pfeiffer, Thomas; Sprenger, Dirk [Schott AG Mainz (Germany); Felser, Claudia, E-mail: felser@uni-mainz.de [Johannes Gutenberg-Universitaet Mainz, Institut fuer Anorganische Chemie und Analytische Chemie (Germany)

    2008-04-15

    In this work Moessbauer spectroscopy is used to investigate the oxidation states and structures of tin in silicate glasses. Thermal treatment of the glasses in atmospheres with varying oxygen partial pressure leads to the simultaneous appearance of reduction and diffusion. Experiments with varying treatment time give the opportunity to study diffusion and reduction processes in detail. Comparison of the hyperfine parameters of reference materials with measured parameter provides information about the local surroundings of the tin atoms. An octahedral surrounding for Sn{sup 4+} is presumed, while Sn{sup 2+} and three oxygen atoms form a tetrahedral coordination.

  12. Infrared Spectroscopy and Stable Isotope Geochemistry of Hydrous Silicate Glasses

    Energy Technology Data Exchange (ETDEWEB)

    Stolper, Edward

    2007-03-05

    The focus of this DOE-funded project has been the study of volatile components in magmas and the atmosphere. Over the twenty-one year period of this project, we have used experimental petrology and stable isotope geochemistry to study the behavior and properties of volatile components dissolved in silicate minerals and melts and glasses. More recently, we have also studied the concentration and isotopic composition of CO2 in the atmosphere, especially in relation to air quality issues in the Los Angeles basin.

  13. Calorimetric signature of structural heterogeneity in a ternary silicate glass

    DEFF Research Database (Denmark)

    Zhang, Yanfei; Yang, G.; Yue, Yuanzheng

    2013-01-01

    We investigate the structural heterogeneity in a silicate glass by hyperquenching–annealing–calorimetry approach. The results show a striking phenomenon: two separated sub-Tg relaxation peaks appear on the calorimetric curve of the hyperquenched CaO–MgO–SiO2 glass, implying the existence of two...... distinct structural domains of higher and lower potential energies, respectively. The higher energy domains in nanoscale are so unstable that they become ordered during hyperquenching. This is verified by the high-resolution transmission electron microscopy image exhibiting nanoordered domains in the glass...

  14. Competitive Adsorption of Arsenite and Silicic Acid on Goethite

    OpenAIRE

    Luxton, Todd Peter

    2002-01-01

    The adsorption behavior of silicic acid and arsenite alone and competitively on goethite over a broad pH range (3-11) at environmentally relevant concentrations was investigated utilizing pH adsorption data and zeta potential measurements. Both addition scenarios (Si before As(III) and As(III) before Si) were examined. The results of the adsorption experiments and zeta potential measurements were then used to model the single ion and competitive ion adsorption on goethite with the CD-MUSIC ...

  15. Electron tunneling transport across heterojunctions between europium sulfide and indium arsenide

    Science.gov (United States)

    Kallaher, Raymond L.

    This dissertation presents research done on utilizing the ferromagnetic semiconductor europium sulfide (EuS) to inject spin polarized electrons into the non-magnetic semiconductor indium arsenide (InAs). There is great interest in expanding the functionality of modern day electronic circuits by creating devices that depend not only on the flow of charge in the device, but also on the transport of spin through the device. Within this mindset, there is a concerted effort to establish an efficient means of injecting and detecting spin polarized electrons in a two dimensional electron system (2DES) as the first step in developing a spin based field effect transistor. Thus, the research presented in this thesis has focused on the feasibility of using EuS, in direct electrical contact with InAs, as a spin injecting electrode into an InAs 2DES. Doped EuS is a concentrated ferromagnetic semiconductor, whose conduction band undergoes a giant Zeeman splitting when the material becomes ferromagnetic. The concomitant difference in energy between the spin-up and spin-down energy bands makes the itinerant electrons in EuS highly spin polarized. Thus, in principle, EuS is a good candidate to be used as an injector of spin polarized electrons into non-magnetic materials. In addition, the ability to adjust the conductivity of EuS by varying the doping level in the material makes EuS particularly suited for injecting spins into non-magnetic semiconductors and 2DES. For this research, thin films of EuS have been grown via e-beam evaporation of EuS powder. This growth technique produces EuS films that are sulfur deficient; these sulfur vacancies act as intrinsic electron donors and the resulting EuS films behave like heavily doped ferromagnetic semiconductors. The growth parameters and deposition procedures were varied and optimized in order to fabricate films that have minimal crystalline defects. Various properties and characteristics of these EuS films were measured and compared to

  16. Synthesis, Optical Investigation and Biological Properties of Europium(III) Complexes with 2-(4-Chlorophenyl)-1-(2-Hydroxy-4-Methoxyphenyl)Ethan-1-one and Ancillary Ligands.

    Science.gov (United States)

    Nandal, Poonam; Khatkar, S P; Kumar, Rajesh; Khatkar, Avni; Taxak, V B

    2017-01-01

    Synthesis and photoluminescence behaviour of six novel europium complexes with novel β-hydroxyketone ligand, 2-(4-chlorophenyl)-1-(2-hydroxy-4-methoxyphenyl)ethan-1-one (CHME) and 2,2'-bipyridine (bipy) or neocuproine (neo) or 1,10-phenanthroline (phen) or 5,6-dimethyl-1,10-phenanthroline (dmphen) or bathophenanthroline (bathophen) were reported in solid state. The free ligand CHME and europium complexes, Eu(CHME)3.2H2O [1] Eu(CHME)3.bipy [2], Eu(CHME)3.neo [3], Eu(CHME)3.phen [4], Eu(CHME)3.dmphen [5] and Eu(CHME)3.bathophen [6]were characterized by elemental analysis, FT-IR and 1H-NMR. The photoluminescence emission spectra exhibited four characteristic peaks arising from the 5D0 → 7FJ (J = 1-4) transitions of the europium ion in the solid state on monitoring excitation at λex = 395 nm. The luminescence decay curves of these europium complexes possess single exponential behaviour indicating the presence of a single luminescent species and having only one site symmetry in the complexes. The luminescence quantum efficiency (η) and the experimental intensity parameters, Ω 2 and Ω 4 of europium complexes have also been calculated on the basis of emission spectra and luminescence decay curves. In addition, the antimicrobial and antioxidant activities were also studied of the investigated complexes.

  17. Highly luminescent pure-red-emitting fluorinated β-diketonate europium(III) complex for full solution-processed OLEDs

    Energy Technology Data Exchange (ETDEWEB)

    Martins, Joao P. [CEMDRX, Physics Department, Universidade de Coimbra, Rua Larga, Coimbra P-3004-516 (Portugal); Serviço de Medicina Nuclear, SESARAM E.P.E., Avenida Luís de Camões 57, Funchal 9004-514, Madeira (Portugal); Martín-Ramos, Pablo [CEMDRX, Physics Department, Universidade de Coimbra, Rua Larga, Coimbra P-3004-516 (Portugal); Higher Technical School of Telecommunications Engineering, Universidad de Valladolid, Campus Miguel Delibes, Paseo Belén 15, Valladolid 47011 (Spain); Coya, Carmen, E-mail: carmen.coya@urjc.es [Escuela Superior de Ciencias Experimentales y Tecnología (ESCET), Universidad Rey Juan Carlos, Madrid 28933 (Spain); Silva, Manuela Ramos [CEMDRX, Physics Department, Universidade de Coimbra, Rua Larga, Coimbra P-3004-516 (Portugal); Eusebio, M. Ermelinda S. [Chemistry Department, Faculdade de Ciências e Tecnologia, Universidade de Coimbra, Coimbra P-3004-535 (Portugal); Andrés, Alicia de [Instituto de Ciencia de Materiales de Madrid, Consejo Superior de Investigaciones Científicas (CSIC), Cantoblanco, Madrid 28049 (Spain); Álvarez, Ángel L. [Escuela Superior de Ciencias Experimentales y Tecnología (ESCET), Universidad Rey Juan Carlos, Madrid 28933 (Spain); Martín-Gil, Jesús [Advanced Materials Laboratory, ETSIIAA, Universidad de Valladolid, Avenida de Madrid 44, Palencia 34004 (Spain)

    2015-03-15

    Current manufacturing technologies for OLEDs involve the use of expensive high vacuum techniques and call for thermal stability requirements which are not fulfilled by many materials. These problems disappear when the OLED films are deposited directly from solution. In this study, we have designed, synthesized and characterized a novel octacoordinated complex, Tris(1-(4-chlorophenyl)-4,4,4-trifluoro-1, 3-butanedionate)mono(bathophenanthroline) europium(III), to be used as a “complex-only” emissive layer in wet-processed OLEDs. Upon excitation in the UV region, very efficient energy transfer from the ligands to Eu{sup 3+} takes place, giving rise to intense red emission with very high monochromaticity (R=19), both in powder and as a thin film. The decay times of 754 µs (powder) and 620 µs (thin film) are comparable to those of the most efficient Eu{sup 3+} β-diketonate complexes reported to date. The same energy transfer leading to saturated red and narrow emission is also observed in the OLED device (glass/ITO/PEDOT:PSS/[Eu(cbtfa){sub 3}(bath)]/Ca/Al) when biased at >5.2 V. Its high quantum efficiency (∼60%), good thermal stability up to 200 °C and adequate thin film forming properties make this material a promising chromophore for cost-effective OLEDs. - Highlights: • A highly fluorinated europium(III) octacoordinated complex, [Eu(cbtfa)3(bath)], has been synthesized and its structure elucidated by single crystal X-ray diffraction. • The chosen coordination environment is well-suited for sensitizing the luminescence of the Eu{sup 3+} ion, achieving very efficient energy transfer from the organic ligands (excited in the UV region) to the rare earth ion, leading to highly efficient (Q∼60% in crystalline powder and Q∼50% in thin film) and saturated red photoluminescence. • The material has also been integrated into a single active layer, full solution-processed OLED, with ITO/PEDOT:PSS/[Eu(cbtfa)3(bath)]/ Ca/Al structure.

  18. Simultaneous analysis of free and humic acid complexed europium and gadolinium species by CE-ICP-MS

    Energy Technology Data Exchange (ETDEWEB)

    Kautenburger, R.; Nowotka, K.; Beck, H.P. [Institut fuer Anorganische und Analytische Chemie und Radiochemie, Universitaet des Saarlandes, P.O. Box 151150, 66041 Saarbruecken (Germany)

    2005-07-01

    Full text of publication follows: For the long-term safety assessment of waste repositories, detailed information about geo-chemical behaviour of radioactive and toxic metal ions under environmental conditions (geological matrix and aquifer systems) is necessary. It includes knowledge about the mechanism of relevant geochemical reactions, as well as thermodynamic and kinetic data. Several previous studies have shown that humic acid can play an important role in the immobilisation or mobilization of metal ions due to complexation and colloid formation. In this project we investigate the complexation behaviour of humic acid (purified Aldrich humic acid) and its influence on the migration of the lanthanides europium and gadolinium (homologues of the actinides americium and curium) in the the ternary system consisting of these heavy metals, humic acid and kaolinite (KGa-1b) as geological model system under conditions close to nature. Capillary electrophoresis (CE, Beckman Coulter P/ACE MDQ), with its excellent separation performance, was coupled to Inductively Coupled Plasma Mass Spectrometry (ICP-MS, VG Elemental Plasma Quad 3) to obtain a high sensitivity for the determination of the rare earth elements europium (Eu{sup 3+}) and gadolinium (Gd{sup 3+}) and their complexes with humic acid. Additionally, the used humic acid was halogenated with iodine as ICP-MS marker. A fused-silica capillary was flexibly fitted into a MicroMist 50 {mu}l nebulizer with a Cinnabar cyclonic spray chamber. The chamber was chilled to a temperature of 4 deg. C for best sensitivity. 200 ppb of caesium were added to the CE separation buffer to observe the capillary flow. A make-up fluid including 4 ppb Ho as an internal standard was combined with the flow from the capillary within the interface to obtain a fluid throughput high enough to maintain a continuous nebulization. Very low detection limits were achieved, 100 ppt for {sup 153}Eu and 125 ppt for {sup 158}Gd. With this optimized CE

  19. NMR study of hydrated calcium silicates; Etude par RMN de la structure des silicates de calcium hydrates

    Energy Technology Data Exchange (ETDEWEB)

    Klur, I

    1996-02-26

    Radioactive wastes storage methods are developed by the CEA. As cements are important materials as well for hours living radioisotopes than for years living radioisotopes, a better knowledge of this material will allow to anticipate its behaviour and to obtain safer storage methods. The structure of calcium silicates (C-S-H) (main constituent of cements) have then been determined in this thesis by nuclear magnetic resonance. This method has allow to explain in structural terms, the different calcium rates that can be measured in the C-S-H too. (O.M.) 101 refs.

  20. Enhanced bioactivity of glass ionomer cement by incorporating calcium silicates.

    Science.gov (United States)

    Chen, Song; Cai, Yixiao; Engqvist, Håkan; Xia, Wei

    2016-01-01

    Glass ionomer cements (GIC) are known as a non-bioactive dental cement. During setting the GIC have an acidic pH, driven by the acrylic acid component. It is a challenge to make GIC alkaline without disturbing its mechanical properties. One strategy was to add slowly reacting systems with an alkaline pH. The aim of the present study is to investigate the possibility of forming a bioactive dental material based on the combination of glass ionomer cement and calcium silicates. Two types of GIC were used as control. Wollastonite (CS also denoted β-CaSiO3) or Mineral Trioxide Aggregate (MTA) was incorporated into the 2 types of GIC. The material formulations' setting time, compressive strength, pH and bioactivity were compared between modified GIC and GIC control. Apatite crystals were found on the surfaces of the modified cements but not on the control GIC. The compressive strength of the cement remained with the addition of 20% calcium silicate or 20% MTA after one day immersion. In addition, the compressive strength of GIC modified with 20% MTA had been increased during the 14 d immersion (p < 0 .05).

  1. Anionic silicate organic frameworks constructed from hexacoordinate silicon centres

    Science.gov (United States)

    Roeser, Jérôme; Prill, Dragica; Bojdys, Michael J.; Fayon, Pierre; Trewin, Abbie; Fitch, Andrew N.; Schmidt, Martin U.; Thomas, Arne

    2017-10-01

    Crystalline frameworks composed of hexacoordinate silicon species have thus far only been observed in a few high pressure silicate phases. By implementing reversible Si-O chemistry for the crystallization of covalent organic frameworks, we demonstrate the simple one-pot synthesis of silicate organic frameworks based on octahedral dianionic SiO6 building units. Clear evidence of the hexacoordinate environment around the silicon atoms is given by 29Si nuclear magnetic resonance analysis. Characterization by high-resolution powder X-ray diffraction, density functional theory calculation and analysis of the pair-distribution function showed that those anionic frameworks—M2[Si(C16H10O4)1.5], where M = Li, Na, K and C16H10O4 is 9,10-dimethylanthracene-2,3,6,7-tetraolate—crystallize as two-dimensional hexagonal layers stabilized in a fully eclipsed stacking arrangement with pronounced disorder in the stacking direction. Permanent microporosity with high surface area (up to 1,276 m2 g-1) was evidenced by gas-sorption measurements. The negatively charged backbone balanced with extra-framework cations and the permanent microporosity are characteristics that are shared with zeolites.

  2. Enhanced bioactivity of glass ionomer cement by incorporating calcium silicates

    Science.gov (United States)

    Chen, Song; Cai, Yixiao; Engqvist, Håkan; Xia, Wei

    2016-01-01

    Abstract Glass ionomer cements (GIC) are known as a non-bioactive dental cement. During setting the GIC have an acidic pH, driven by the acrylic acid component. It is a challenge to make GIC alkaline without disturbing its mechanical properties. One strategy was to add slowly reacting systems with an alkaline pH. The aim of the present study is to investigate the possibility of forming a bioactive dental material based on the combination of glass ionomer cement and calcium silicates. Two types of GIC were used as control. Wollastonite (CS also denoted β-CaSiO3) or Mineral Trioxide Aggregate (MTA) was incorporated into the 2 types of GIC. The material formulations’ setting time, compressive strength, pH and bioactivity were compared between modified GIC and GIC control. Apatite crystals were found on the surfaces of the modified cements but not on the control GIC. The compressive strength of the cement remained with the addition of 20% calcium silicate or 20% MTA after one day immersion. In addition, the compressive strength of GIC modified with 20% MTA had been increased during the 14 d immersion (p < 0 .05). PMID:26787304

  3. Novel understanding of calcium silicate hydrate from dilute hydration

    KAUST Repository

    Zhang, Lina

    2017-05-13

    The perspective of calcium silicate hydrate (C-S-H) is still confronting various debates due to its intrinsic complicated structure and properties after decades of studies. In this study, hydration at dilute suspension of w/s equaling to 10 was conducted for tricalcium silicate (C3S) to interpret long-term hydration process and investigate the formation, structure and properties of C-S-H. Based on results from XRD, IR, SEM, NMR and so forth, loose and dense clusters of C-S-H with analogous C/S ratio were obtained along with the corresponding chemical formulae proposed as Ca5Si4O13∙6.2H2O. Crystalline structure inside C-S-H was observed by TEM, which was allocated at the foil-like proportion as well as the edge of wrinkles of the product. The long-term hydration process of C3S in dilute suspension could be sketchily described as migration of calcium hydroxide and in-situ growth of C-S-H with equilibrium silicon in aqueous solution relatively constant and calcium varied.

  4. Anionic silicate organic frameworks constructed from hexacoordinate silicon centres.

    Science.gov (United States)

    Roeser, Jérôme; Prill, Dragica; Bojdys, Michael J; Fayon, Pierre; Trewin, Abbie; Fitch, Andrew N; Schmidt, Martin U; Thomas, Arne

    2017-10-01

    Crystalline frameworks composed of hexacoordinate silicon species have thus far only been observed in a few high pressure silicate phases. By implementing reversible Si-O chemistry for the crystallization of covalent organic frameworks, we demonstrate the simple one-pot synthesis of silicate organic frameworks based on octahedral dianionic SiO6 building units. Clear evidence of the hexacoordinate environment around the silicon atoms is given by (29)Si nuclear magnetic resonance analysis. Characterization by high-resolution powder X-ray diffraction, density functional theory calculation and analysis of the pair-distribution function showed that those anionic frameworks-M2[Si(C16H10O4)1.5], where M = Li, Na, K and C16H10O4 is 9,10-dimethylanthracene-2,3,6,7-tetraolate-crystallize as two-dimensional hexagonal layers stabilized in a fully eclipsed stacking arrangement with pronounced disorder in the stacking direction. Permanent microporosity with high surface area (up to 1,276 m(2) g(-1)) was evidenced by gas-sorption measurements. The negatively charged backbone balanced with extra-framework cations and the permanent microporosity are characteristics that are shared with zeolites.

  5. The structure of alkali silicate gel by total scattering methods

    KAUST Repository

    Benmore, C.J.

    2010-06-01

    The structure of the alkali silicate gel (ASR) collected from the galleries of Furnas Dam in Brazil was determined by a pair distribution function (PDF) analysis of high energy X-ray diffraction data. Since this method is relatively new to concrete structure analysis a detailed introduction on the PDF method is given for glassy SiO2. The bulk amorphous structure of the dam material is confirmed as no Bragg peaks are observed in the scattered intensity. The real space results show that the local structure of the amorphous material is similar to kanemite (KHSi2O5:3H2O) however the long range layer structure of the crystal is broken up in the amorphous state, so that ordering only persists of the length scale of a few polyhedra. The silicate layer structure is a much more disordered than predicted by molecular dynamics models. The X-ray results are consistent with the molecular dynamics model of Kirkpatrick et al. (2005) [1] which predicts that most of the water resides in pores within the amorphous network rather than in layers. The total scattering data provide a rigorous basis against which other models may also be tested. © 2010.

  6. Evidence of yttrium silicate inclusions in YSZ-porcelain veneers.

    Science.gov (United States)

    Stoner, Brian R; Griggs, Jason A; Neidigh, John; Piascik, Jeffrey R

    2014-04-01

    This report introduces the discovery of crystalline defects that can form in the porcelain veneering layer when in contact with yttria-stabilized zirconia (YSZ). The focus was on dental prostheses and understanding the defects that form in the YSZ/porcelain system; however the data reported herein may have broader implications toward the use and stability of YSZ-based ceramics in general. Specimens were cut from fully sintered YSZ plates and veneering porcelain was applied (veneer. Local EDAX (SEM) was performed in the regions of visible inclusions and showed significant increases in yttrium concentration. TEM specimens also showed apparent inclusions in the porcelain and selected area electron diffraction was performed on these regions and found the inclusions to be crystalline and identified as either yttrium-silicate (Y2 SiO5 ) or yttrium-disilicate (Y2 Si2 O7 ). Micro-CT data showed that yttrium-silicate precipitates were distributed throughout the thickness of the porcelain veneer. Future studies are needed to determine whether many of the premature failures associated with this materials system may be the result of crystalline flaws that form as a result of high temperature yttrium diffusion near the surfaces of YSZ. © 2013 Wiley Periodicals, Inc.

  7. In vitro bioactivity of a tricalcium silicate cement

    Energy Technology Data Exchange (ETDEWEB)

    Morejon-Alonso, L.; Bareiro, O.; Santos, L.A. dos, E-mail: loreley.morejon@ufrgs.b [Universidade Federal do Rio Grande do Sul (UFRG), Porto Alegre, RS (Brazil). Escola de Engenharia. Dep. de Materiais; Carrodeguas R, Garcia [Consejo Superior de Investigaciones Cientificas (CSIC), Madrid (Spain). Inst. de Ceramica y Vidrio. Dept. de Ceramica

    2009-07-01

    Tricalcium silicate is the major constituent of Portland cement and the responsible for their mechanical strength at early stages. In order to be used as and additive of conventional calcium phosphate cement (CPC), in vitro bioactivity of a calcium silicate cement (CSC) after soaking in simulated body fluid (SBF) for 14 days was study. The cement was obtained by mixing Ca{sub 3}SiO{sub 5}, obtained by sol-gel process, and a Na{sub 2}HPO{sub 4} solution. The morphological and structural changes of the material before and after soaking were analyzed by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results showed the formation of a layer of a Hydroxyapatite (HA) onto the CSC cement after soaking for 1h in SBF that became denser with the increase of soaking time. The study suggests that Ca{sub 3}SiO{sub 5} would be an effective additive to improve the bioactivity and long term strength of conventional CPC. (author)

  8. Temperature effects on the interaction mechanisms between the europium (III) and uranyl ions and zirconium diphosphate; Effets de la temperature sur les mecanismes d'interaction entre les ions europium (3) et uranyle et le diphosphate de zirconium

    Energy Technology Data Exchange (ETDEWEB)

    Finck, N

    2006-10-15

    Temperature should remain higher than 25 C in the near field environment of a nuclear waste repository for thousands years. In this context, the aim of this work is to study the temperature influence on the interaction mechanisms between europium (III) and uranyl ions and zirconium diphosphate, as well as the influence of a complexing medium (nitrate) on the sorption of the lanthanide. The experimental definition of the equilibria was achieved by combining a structural investigation with the macroscopic sorption data. Surface complexes were characterized at all temperatures (25 C to 90 C) by TRLFS experiments carried out on dry and in situ samples using an oven. This characterization was completed by XPS experiments carried out at 25 C on samples prepared at 25 C and 90 C. The reaction constants (surface hydration and cations sorption) were obtained by simulating the experimental data with the constant capacitance surface complexation model. The reaction constants temperature dependency allowed one to characterize thermodynamically the different reactions by application of the van't Hoff relation. The validity of this law was tested by performing microcalorimetric measurements of the sorption heat for both cations. (author)

  9. Interaction of dispersed polyvynil acetate with silicate in finishing materials

    Directory of Open Access Journals (Sweden)

    Runova, R. F.

    1996-12-01

    Full Text Available This article focuses on the processes of interaction between calcium silicate hydrates and dispersed polyvinyl acetate in tight films with the aim of developing compounds meant for restoration and finishing works. The basis of this development relies on the concept concerning the determining role of the crystal-chemical factor of the silicate phase in the formation of organic-mineral compounds of increased durability. The characteristics of dispersed calcium silicate hydrates are portrayed. The preparation conditions, accounting for the synthesis of the product of submicrocrystalline structure, conforming with the stoichiometry CaO∙SiO2 =0.8-2.0 have been determined. The interaction has been studied for compounds achieved by mixing ingredients in a rapid whirling mixer, and subjected to hardening at T=20+2 T. With the aid of XRD, DTA and Infra-Red Spectrometry methods the formation process of the sophisticated polymer silicate phase in the material was observed for a period of 90 days. The properties of the film were investigated and its high resistance against the influence of external factors was established. On this basis a conclusion concerning the quite high effectiveness of substituting portland cement with dispersed calcium silicate hydrate in polymer cement compounds has been made. White colour and other various special properties determine the suitability for repair and finishing works on facades of buildings.

    Este artículo está orientado a estudiar los procesos de interacción entre los silicatos cálcicos hidratados y el acetato de polivinilo disperso en capas impermeables, con el objeto de desarrollar compuestos destinados para la restauración. El fundamento de estos estudios es determinar el papel que los factores cristaloquímicos de las fases silicato tienen en la formación de compuestos órganominerales de elevada durabilidad. Se han descrito las características de los silicatos cálcicos hidratados

  10. Influence of silicate on the transport of bacteria in quartz sand and iron mineral-coated sand.

    Science.gov (United States)

    Dong, Zhe; Yang, Haiyan; Wu, Dan; Ni, Jinren; Kim, Hyunjung; Tong, Meiping

    2014-11-01

    The influence of silicate on the transport and deposition of bacteria (Escherichia coli) in packed porous media were examined at a constant 20 mM ionic strength with different silicate concentrations (from 0 to 1 mM) at pH 7. Transport experiments were performed in two types of representative porous media, both bare quartz sand and iron mineral-coated quartz sand. In bare quartz sand, the breakthrough plateaus in the presence of silicate in suspensions were lower and the corresponding retained profiles were higher than those without silicate ions, indicating that the presence of silicate in suspensions decreased cell transport in bare quartz sand. Moreover, the decrease of bacteria transport in quartz sand induced by silicate was more pronounced with increasing silicate concentrations from 0 to 1 mM. However, when EPS was removed from cell surfaces, the presence of silicate in cell suspensions (with different concentrations) did not affect the transport behavior of bacteria in quartz sand. The interaction of silicate with EPS on cell surfaces negatively decreased the zeta potentials of bacteria, resulting in the decreased cell transport in bare quartz sand when silicate was copresent in bacteria suspensions. In contrast, the presence of silicate in suspensions increased cell transport in iron mineral-coated sand. Silicate ions competed with bacteria for the adsorption sites on mineral-coated sand, contributing to the increased cell transport in mineral-coated sand with silicate present in cell suspensions. Copyright © 2014 Elsevier B.V. All rights reserved.

  11. Quantum dot based on tin/titanium mixed oxide doped with europium synthesized by protein sol-gel method

    Energy Technology Data Exchange (ETDEWEB)

    Paganini, Paula P.; Felinto, Maria Claudia F.C., E-mail: paulapaganini@usp.b, E-mail: mfelinto@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Brito, Hermi F., E-mail: hefbrito@iq.usp.b [Universidade de Sao Paulo (IQ/USP), Sao Paulo, SP (Brazil). Inst. de Quimica. Lab. de Elementos do Bloco f

    2011-07-01

    Special luminescence biomarkers have been developed to find more sensitive fluoroimmunoassay methods. A new generation of these biomarkers is the semiconductors nanocrystals, known as quantum dots, doped with lanthanides. The use of lanthanides ions as luminescent markers has many advantages, for example a security method, low cost, high specificity and also the luminescence can be promptly measured with high sensibility and accuracy. The protein sol-gel is a modification of conventional method, in which the coconut water replacing the alkoxides normally used. The advantage is that, the proteins present in coconut water bind chemically with metal salts forming a polymer chain. This work presents nanoparticles based on tin/titanium mixed oxide doped with 3% of europium synthesized by protein sol-gel method. The nanoparticles were burned at 300 deg C, 500 deg C, 800 deg C and 1100 deg C. The samples were analyzed and characterized by thermal analysis, X-ray powder diffraction (XRD), infrared spectroscopy (IR) and scanning electron microscopy (SEM). The synthesis was effective and the nanoparticles showed nanometric size and structural differences with the annealing. To be used in the fluoroimmunoassays tests, these particles need to be functionalized before be connect with biological molecules and after this process, these nanoparticles going to be submitted at gamma radiation for sterilization. (author)

  12. 340nm UV LED excitation in time-resolved fluorescence system for europium-based immunoassays detection

    Science.gov (United States)

    Rodenko, Olga; Fodgaard, Henrik; Tidemand-Lichtenberg, Peter; Pedersen, Christian

    2017-02-01

    In immunoassay analyzers for in-vitro diagnostics, Xenon flash lamps have been widely used as excitation light sources. Recent advancements in UV LED technology and its advantages over the flash lamps such as smaller footprint, better wall-plug efficiency, narrow emission spectrum, and no significant afterglow, have made them attractive light sources for gated detection systems. In this paper, we report on the implementation of a 340 nm UV LED based time-resolved fluorescence system based on europium chelate as a fluorescent marker. The system performance was tested with the immunoassay based on the cardiac marker, TnI. The same signal-to-noise ratio as for the flash lamp based system was obtained, operating the LED below specified maximum current. The background counts of the system and its main contributors were measured and analyzed. The background of the system of the LED based unit was improved by 39% compared to that of the Xenon flash lamp based unit, due to the LEDs narrower emission spectrum and longer pulse width. Key parameters of the LED system are discussed to further optimize the signal-to-noise ratio and signal-to-background, and hence the sensitivity of the instrument.

  13. Interaction of europium and nickel with calcite studied by Rutherford Backscattering Spectrometry and Time-Resolved Laser Fluorescence Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Sabau, A. [Agence Nationale pour la gestion des Déchets RAdioactifs, 1-7 rue J. Monnet, Parc de la Croix Blanche, 92298 Châtenay-Malabry Cedex (France); Université de Nice Sophia Antipolis, Ecosystèmes Côtiers Marins et Réponses aux Stress (ECOMERS), 28 avenue Valrose, 06108 Nice Cedex 2 (France); Pipon, Y., E-mail: pipon@ipnl.in2p3.fr [Institut de Physique Nucléaire de Lyon (IPNL), Université Lyon 1, CNRS/IN2P3, 4 rue Enrico Fermi, 69 622 Villeurbanne Cedex (France); Institut Universitaire de Technologie (IUT) Lyon-1, Université Claude Bernard Lyon 1, 69 622 Villeurbanne Cedex (France); Toulhoat, N. [Institut de Physique Nucléaire de Lyon (IPNL), Université Lyon 1, CNRS/IN2P3, 4 rue Enrico Fermi, 69 622 Villeurbanne Cedex (France); CEA/DEN, Saclay, 91191 Gif sur Yvette (France); Lomenech, C. [Université de Nice Sophia Antipolis, Ecosystèmes Côtiers Marins et Réponses aux Stress (ECOMERS), 28 avenue Valrose, 06108 Nice Cedex 2 (France); Jordan, N. [Helmholtz Zentrum Dresden Rossendorf (HZDR), Institute of Resource Ecology (IRE) (Germany); Moncoffre, N. [Institut de Physique Nucléaire de Lyon (IPNL), Université Lyon 1, CNRS/IN2P3, 4 rue Enrico Fermi, 69 622 Villeurbanne Cedex (France); Barkleit, A. [Helmholtz Zentrum Dresden Rossendorf (HZDR), Institute of Resource Ecology (IRE) (Germany); and others

    2014-08-01

    This study aims at elucidating the mechanisms regulating the interaction of Eu and Ni with calcite (CaCO{sub 3}). Calcite powders or single crystals (some mm sized) were put into contact with Eu or Ni solutions at concentrations ranging from 10{sup −3} to 10{sup −5} mol L{sup −1} for Eu and 10{sup −3} mol L{sup −1} for Ni. The sorption durations ranged from 1 week to 1 month. Rutherford Backscattering Spectrometry (RBS) well adapted to discriminate incorporation processes such as: (i) adsorption or co precipitation at the mineral surfaces or, (ii) incorporation into the mineral structure (through diffusion for instance), has been carried out. Moreover, using the fluorescence properties of europium, the results have been compared to those obtained by Time-Resolved Laser Fluorescence Spectroscopy (TRLFS) on calcite powders. For the single crystals, complementary SEM observations of the mineral surfaces at low voltage were also performed. Results showed that Ni accumulates at the calcite surface whereas Eu is also incorporated at a greater depth. Eu seems therefore to be incorporated into two different states in calcite: (i) heterogeneous surface accumulation and (ii) incorporation at depth greater than 160 nm after 1 month of sorption. Ni was found to accumulate at the surface of calcite without incorporation.

  14. Application of Europium Multiwalled Carbon Nanotubes as Novel Luminophores in an Electrochemiluminescent Aptasensor for Thrombin Using Multiple Amplification Strategies.

    Science.gov (United States)

    Wu, Dan; Xin, Xia; Pang, Xuehui; Pietraszkiewicz, Marek; Hozyst, Robert; Sun, Xian'ge; Wei, Qin

    2015-06-17

    A novel electrochemiluminescent (ECL) aptasensor was proposed for the determination of thrombin (TB) using exonuclease-catalyzed target recycling and hybridization chain reaction (HCR) to amplify the signal. The capture probe was immobilized on an Au-GS-modified electrode through a Au-S bond. Subsequently, the hybrid between the capture probe and the complementary thrombin binding aptamer (TBA) was aimed at obtaining double-stranded DNA (dsDNA). The interaction between TB and its aptamer led to the dissociation of dsDNA because TB has a higher affinity to TBA than the complementary strands. In the presence of exonuclease, aptamer was selectively digested and TB could be released for target recycling. Extended dsDNA was formed through HCR of the capture probe and two hairpin DNA strands (NH2-DNA1 and NH2-DNA1). Then, numerous europium multiwalled carbon nanotubes (Eu-MWCNTs) could be introduced through amidation reaction between NH2-terminated DNA strands and carboxyl groups on the Eu-MWCNTs, resulting in an increased ECL signal. The multiple amplification strategies, including the amplification of analyte recycling and HCR, and high ECL efficiency of Eu-MWCNTs lead to a wide linear range (1.0×10(-12)-5.0×10(-9) mol/L) and a low detection limit (0.23 pmol/L). The method was applied to serum sample analysis with satisfactory results.

  15. Spectrophotometric Determination and Removal of Unchelated Europium Ions from Solutions Containing Eu-Diethylenetriaminepentaacetic Acid Chelate-Peptide Conjugates1

    Science.gov (United States)

    Dayan Elshan, N. G. R.; Patek, Renata; Vagner, Josef; Mash, Eugene A.

    2014-01-01

    Europium chelates conjugated with peptide ligands are routinely used as probes for conducting in vitro binding experiments. The presence of unchelated Eu ions in these formulations gives high background luminescence and can lead to poor results in binding assays. In our experience, the reported methods for purification of these probes do not achieve adequate removal of unchelated metal ions in a reliable manner. In this work, a xylenol orange-based assay for the quantification of unchelated metal ions was streamlined and used to determine levels of metal ion contamination, as well as the success of metal ion removal upon attempted purification. We compared the use of Empore™ chelating disks and Chelex® 100 resin for the selective removal of unchelated Eu ions from several Eu-diethylenetriaminepentaacetic acid chelate-peptide conjugates. Both purification methods gave complete and selective removal of the contaminant metal ions. However, Empore™ chelating disks were found to give much higher recoveries of the probes under the conditions utilized. Related to the issue of probe recovery, we also describe a significantly more efficient method for the synthesis of one such probe using Rink amide AM resin in place of Tentagel S resin. PMID:25058927

  16. Reusable temperature-sensitive luminescent material based on vitrified film of europium(III) β-diketonate complex

    Science.gov (United States)

    Lapaev, Dmitry V.; Nikiforov, Victor G.; Lobkov, Vladimir S.; Knyazev, Andrey A.; Galyametdinov, Yury G.

    2018-01-01

    We have proposed a novel temperature-sensitive luminescent material which is a 20 μm thick vitrified film (sandwiched between two quartz plates) fabricated from an amorphous powder of a mesogenic europium(III) β-diketonate complex through a melt-processing technique. The film photoexcited by a 337 nm pulsed nitrogen laser displays a typical Eu3+ ion luminescence bands with the strongest peak at 612 nm and with the decay time of 537 μs at 298 K. It is obtained that both the mean luminescence intensity and the luminescence decay time at 612 nm decrease significantly with temperature increasing from 298 to 348 K; the average values of the relative and absolute temperature sensitivities of the luminescence decay time in the range of 298-348 K are -1.2%·K-1 and -6.5 μs·K-1, respectively. The thermal quenching mechanism of the luminescent properties was analyzed and discussed. The experiments showed that, the luminescent properties of the film is insensitive to oxygen, the film is photostable under UV light, there is full reversibility of the temperature-dependent luminescence intensity and the decay time, and the high luminescence brightness of the film can be observed with violet light excitation. These factors indicated that the film is promising material for reusable luminescent thermometers, suitable for long-term monitoring in the range of 298-348 K.

  17. Differential ERK activation during autophagy induced by europium hydroxide nanorods and trehalose: Maximum clearance of huntingtin aggregates through combined treatment.

    Science.gov (United States)

    Wei, Peng-Fei; Jin, Pei-Pei; Barui, Ayan Kumar; Hu, Yi; Zhang, Li; Zhang, Ji-Qian; Shi, Shan-Shan; Zhang, Hou-Rui; Lin, Jun; Zhou, Wei; Zhang, Yun-Jiao; Ruan, Ren-Quan; Patra, Chitta Ranjan; Wen, Long-Ping

    2015-12-01

    Accelerating the clearance of intracellular protein aggregates through elevation of autophagy represents a viable approach for the treatment of neurodegenerative diseases. In our earlier report, we have demonstrated the enhanced degradation of mutant huntingtin protein aggregates through autophagy process induced by europium hydroxide nanorods [EHNs: Eu(III)(OH)3], but the underlying molecular mechanism of EHNs mediated autophagy was unclear. The present report reveals that EHNs induced autophagy does not follow the classical AKT-mTOR and AMPK signaling pathways. The inhibition of ERK1/2 phosphorylation using the specific MEK inhibitor U0126 partially abrogates the autophagy as well as the clearance of mutant huntingtin protein aggregates mediated by EHNs suggesting that nanorods stimulate the activation of MEK/ERK1/2 signaling pathway during autophagy process. In contrast, another mTOR-independent autophagy inducer trehalose has been found to induce autophagy without activating ERK1/2 signaling pathway. Interestingly, the combined treatment of EHNs and trehalose leads to more degradation of mutant huntingtin protein aggregates than that obtained with single treatment of either nanorods or trehalose. Our results demonstrate the rational that further enhanced clearance of intracellular protein aggregates, needed for diverse neurodegenerative diseases, may be achieved through the combined treatment of two or more autophagy inducers, which stimulate autophagy through different signaling pathways. Copyright © 2015 Elsevier Ltd. All rights reserved.

  18. Synthesis of europium-doped VSOP, customized enhancer solution and improved microscopy fluorescence methodology for unambiguous histological detection.

    Science.gov (United States)

    de Schellenberger, Angela Ariza; Hauptmann, Ralf; Millward, Jason M; Schellenberger, Eyk; Kobayashi, Yuske; Taupitz, Matthias; Infante-Duarte, Carmen; Schnorr, Jörg; Wagner, Susanne

    2017-10-10

    Intrinsic iron in biological tissues frequently precludes unambiguous the identification of iron oxide nanoparticles when iron-based detection methods are used. Here we report the full methodology for synthesizing very small iron oxide nanoparticles (VSOP) doped with europium (Eu) in their iron oxide core (Eu-VSOP) and their unambiguous qualitative and quantitative detection by fluorescence. The resulting Eu-VSOP contained 0.7 to 2.7% Eu relative to iron, which was sufficient for fluorescent detection while not altering other important particle parameters such as size, surface charge, or relaxivity. A customized enhancer solution with high buffer capacity and nearly neutral pH was developed to provide an antenna system that allowed fluorescent detection of Eu-VSOP in cells and histologic tissue slices as well as in solutions even under acidic conditions as frequently obtained from dissolved organic material. This enhancer solution allowed detection of Eu-VSOP using a standard fluorescence spectrophotometer and a fluorescence microscope equipped with a custom filter set with an excitation wavelength (λex) of 338 nm and an emission wavelength (λem) of 616 nm. The fluorescent detection of Eu-doped very small iron oxide nanoparticles (Eu-VSOP) provides a straightforward tool to unambiguously characterize VSOP biodistribution and toxicology at tissue, and cellular levels, providing a sensitive analytical tool to detect Eu-doped IONP in dissolved organ tissue and biological fluids with fluorescence instruments.

  19. Efficient solution-processed double-layer red OLEDs based on a new europium complex with a carbazole group.

    Science.gov (United States)

    Liu, Jian; Miao, Jing-Sheng; Wu, Hong-Bin

    2015-06-01

    A new europium complex EuL3 (Phen) was used as guest dopant, and a blend of Polyvinylcarbazole and 2-(biphenyl-4-yl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (PVK and PBD) as host matrix. Efficient red organic light-emitting devices (OLEDs) with double-layer structures were manufactured via a solution-processed technique. The guest-doped levels were 1, 3 and 5 wt% relative to the blend mass, respectively. For the 1 wt% doping-level device, the luminous efficiency and luminance were up to 2.96 cd/A and 635.78 cd/m(2) with emissions from both EuL3 (Phen) and from the host; for the 3 wt% doping-level device, the maximum luminous efficiency and luminance were 1.01 cd/A and 370.91 cd/m(2) for the single emission from EuL3 (Phen) only. Copyright © 2014 John Wiley & Sons, Ltd.

  20. Europium Nanospheres-Based Time-Resolved Fluorescence for Rapid and Ultrasensitive Determination of Total Aflatoxin in Feed.

    Science.gov (United States)

    Wang, Du; Zhang, Zhaowei; Li, Peiwu; Zhang, Qi; Ding, Xiaoxia; Zhang, Wen

    2015-12-02

    Immunochromatographic (IC) assays are considered suitable diagnostic tools for the determination of mycotoxins. A europium nanospheres-based time-resolved fluorescence immunoassay (Eu-Nano-TRFIA), based on a monoclonal antibody and a portable TRFIA reader, was developed to determine total aflatoxin (including aflatoxins B1, B2, G1, and G2) levels in feed samples. Under optimized conditions, the Eu-Nano-TRFIA method detected total aflatoxin within 12 min. It showed good linearity (R(2) > 0.985), LOD of 0.16 μg/kg, a wide dynamic range of 0.48-30.0 μg/kg, recovery rates of 83.9-113.9%, and coefficients of variation (CVs) of 3.5-8.8%. In the 397 samples from company and livestock farms throughout China, the detection rate was 78.3%, concentrations were 0.50-145.30 μg/kg, the highest total aflatoxin content was found in cottonseed meal, and corn was found to be the most commonly contaminated feed. This method could be a powerful alternative for the rapid and ultrasensitive determination of total aflatoxin in quality control and meet the required Chinese maximum residue limits.

  1. Spectrophotometric determination and removal of unchelated europium ions from solutions containing Eu-diethylenetriaminepentaacetic acid chelate-peptide conjugates.

    Science.gov (United States)

    Elshan, N G R Dayan; Patek, Renata; Vagner, Josef; Mash, Eugene A

    2014-11-01

    Europium chelates conjugated with peptide ligands are routinely used as probes for conducting in vitro binding experiments. The presence of unchelated Eu ions in these formulations gives high background luminescence and can lead to poor results in binding assays. In our experience, the reported methods for purification of these probes do not achieve adequate removal of unchelated metal ions in a reliable manner. In this work, a xylenol orange-based assay for the quantification of unchelated metal ions was streamlined and used to determine levels of metal ion contamination as well as the success of metal ion removal on attempted purification. We compared the use of Empore chelating disks and Chelex 100 resin for the selective removal of unchelated Eu ions from several Eu-diethylenetriaminepentaacetic acid chelate-peptide conjugates. Both purification methods gave complete and selective removal of the contaminant metal ions. However, Empore chelating disks were found to give much higher recoveries of the probes under the conditions used. Related to the issue of probe recovery, we also describe a significantly more efficient method for the synthesis of one such probe using Rink amide AM resin in place of Tentagel S resin. Copyright © 2014 Elsevier Inc. All rights reserved.

  2. Formation and structural characterization of a europium(II mono(scorpionate complex and a sterically crowded pyrazabole

    Directory of Open Access Journals (Sweden)

    Phil Liebing

    2017-12-01

    Full Text Available The reaction of EuI2(THF2 with potassium hydrotris(3,5-diisopropylpyrazolylborate (K[HB(3,5-iPr2pz3] (= KTpiPr2, pz = pyrazolyl in a molar ratio of 1:1.5 resulted in extensive ligand fragmentation and formation of the europium(II mono(scorpionate complex bis(3,5-diisopropyl-1H-pyrazole[hydrotris(3,5-diisopropylpyrazolylborato]iodidoeuropium(II, [Eu(C27H46BN6I(C9H16N22] or (TpiPr2(3,5-iPr2pzH2EuIII, 1, in high yield (78%. As a typical by-product, small amounts of the sterically crowded pyrazabole derivative trans-4,8-bis(3,5-diisopropylpyrazol-1-yl-1,3,5,7-tetraisopropylpyrazabole, C36H62B2H8 or trans-{(3,5-iPr2pzHB(μ-3,5-iPr2pz}2, 2, were formed. Both title compounds have been structurally characterized through single-crystal X-ray diffraction. In 1, two isopropyl groups are each disordered over two orientations with occupancy ratios of 0.574 (10:0.426 (10 and 0.719 (16:0.281 (16. In 2, one isopropyl group is similarly disordered, occupancy ratio 0.649 (9:0.351 (9.

  3. Spectrofluorimetric study of the interaction between europium(III) and moxifloxacin in micellar solution and its analytical application

    Science.gov (United States)

    Kamruzzaman, Mohammad; Alam, Al-Mahmnur; Lee, Sang Hak; Ragupathy, Dhanusuraman; Kim, Young Ho; Park, Sang-Ryoul; Kim, Sung Hong

    2012-02-01

    A sensitive spectrofluorimetric method has been developed for the determination of moxifloxacin (MOX) using europium(III)-MOX complex as a fluorescence probe in the presence of an anionic surfactant, sodium dodecyl benzene sulfonate (SDBS). The fluorescence (FL) intensity of Eu 3+ was enhanced by complexation with MOX at 614 nm after excitation at 373 nm. The FL intensity of the Eu 3+-MOX complex was significantly intensified in the presence of SDBS. Under the optimum conditions, it was found that the enhanced FL intensity of the system showed a good linear relationship with the concentration of MOX over the range of 1.8 × 10 -11-7.3 × 10 -9 g mL -1 with a correlation coefficient of 0.9998. The limit of detection of MOX was found to be 2.8 × 10 -12 g mL -1 with relative standard deviation (RSD) of 1.25% for 5 replicate determination of 1.5 × 10 -8 g mL -1 MOX. The proposed method is simple, offers higher sensitivity with wide linear range and can be successfully applied to determine MOX in pharmaceutical and biological samples with good reproducibility. The luminescence mechanism is also discussed in detail with ultraviolet absorption spectra.

  4. Highly selective luminescent sensing of picric acid based on a water-stable europium metal-organic framework

    Energy Technology Data Exchange (ETDEWEB)

    Xia, Tifeng; Zhu, Fengliang; Cui, Yuanjing, E-mail: cuiyj@zju.edu.cn; Yang, Yu; Wang, Zhiyu; Qian, Guodong, E-mail: gdqian@zju.edu.cn

    2017-01-15

    A water-stable metal-organic framework (MOF) EuNDC has been synthesized for selective detection of the well-known contaminant and toxicant picric acid (PA) in aqueous solution. Due to the photo-induced electron transfer and self-absorption mechanism, EuNDC displayed rapid, selective and sensitive detection of PA with a detection limit of 37.6 ppb. Recyclability experiments revealed that EuNDC retains its initial luminescent intensity and same quenching efficiency in each cycle, suggesting high photostability and reusability for long-term sensing applications. The excellent detection performance of EuNDC makes it a promising PA sensing material for practical applications. - Graphical abstract: A water-stable europium-based metal-organic framework has been reported for highly selective sensing of picric acid (PA) with a detection limit of 37.6 ppb in aqueous solution. - Highlights: • A water-stable metal-organic framework (MOF) EuNDC was synthesized. • The highly selective detection of picric acid with a detection limit of 37.6 ppb was realized. • The detection mechanism were also presented and discussed.

  5. One-pot carbonization synthesis of europium-doped carbon quantum dots for highly selective detection of tetracycline

    Science.gov (United States)

    Li Liu, Meng; Chen, Bin Bin; Yang, Tong; Wang, Jian; Liu, Xi Dong; Zhi Huang, Cheng

    2017-03-01

    The detection of tetracycline is of great significance because of its damaging effects on human health, such as renal toxicity and hemolytic anemia. Any release of tetracycline into the surrounding environment can produce bacterial drug resistance. We develop a new sensitive and selective detection approach for tetracycline in complex water samples by preparing europium-doped carbon quantum dots (Eu-CQDs) through a simple and rapid carbonization method operating at 200 °C for 5 min. The Eu-CQDs are characterized by blue photoluminescence, excitation-wavelength-dependent emission and excellent stability. Importantly, the fluorescence of the Eu-CQDs can be quenched efficiently by tetracycline, based on the strong inner filter effect mechanism between Eu-CQDs and tetracycline, making the fluorescence intensity ratio (I 0/I) of the Eu-CQDs at 465 nm correlate linearly with the concentration of tetracycline in the range of 0.5-200 μM, with a limit of detection of 0.3 μM. This shows the broad applicability of the Eu-CQDs in pursuing the concepts of simplicity and specificity for analytical purposes.

  6. Mesoporous Europium-Doped Titania Nanoparticles (Eu-MTNs) for Luminescence-Based Intracellular Bio-Imaging.

    Science.gov (United States)

    Chen, Kuan-Chou; Dutta, Saikat; Yamauchi, Yusuke; Alshehri, Saad M; Nguyen, Mai Thanh; Yonezawa, Tetsu; Shen, Kun-Hung; Wu, Kevin C W

    2015-12-01

    Monodisperse and mesoporous europium (Eu)-doped titania nanoparticles (denoted as Eu-MTNs) were prepared by a co-synthesis method with the presence of a cationic surfactant (i.e., CTAB). A maximum loading amount of 8 mol% of Eu could be successfully incorporated into the framework of MTNs. The synthesized Eu-MTNs samples were characterized with X-ray diffraction (XRD) and scanning electron microscopy (SEM), with their luminescent property examined by photoluminescence (PL). Under ultraviolet irradiation, the Eu-MTNs samples exhibit several characteristic luminescence corresponding to 5D0-7F(j) for Eu+3 ions, which can be attributed to the energy transfer from titania nanocrystallite to Eu3+ ions dispersed in amorphous mesoporous titania region. The potential intracellular bio-imaging application of the synthesized Eu-MTN nanoparticles was demonstrated with a breast cancer cell line (i.e., BT-20). High biocompatibility and strong luminescence of the Eu-MTNs show great potential in biomedical applications.

  7. A study of redox kinetic in silicate melt; Etude cinetique des reactions d'oxydoreduction dans les silicates

    Energy Technology Data Exchange (ETDEWEB)

    Magnien, V

    2005-12-15

    The aim of this thesis is to understand better iron redox reactions and mechanisms in silicate glasses and melts. Particular interest has been paid to the influence of temperature and chemical composition. For this purpose, the influence of alkali element content, iron content and network formers on the kinetics of redox reactions has been determined through XANES and Raman spectroscopy experiments performed either near the glass transition or above the liquidus temperature. As a complement, electrical conductivity and RBS spectroscopy experiments have been made to characterize the diffusivity of the species that transport electrical charges and the reaction morphology, respectively. Temperature and composition variations can induce changes in the dominating redox mechanism. At a given temperature, the parameters that exert the strongest influence on redox mechanisms are the presence or lack of divalent cations and the existing decoupling between the mobility of network former and modifier elements. Near Tg, the diffusion of divalent cations, when present in the melt, controls the kinetics of iron redox reactions along with a flux of electron holes. Composition, through the degree of polymerization and the silicate network structure, influences the kinetics and the nature of the involved cations, but not the mechanisms of the reaction. Without alkaline earth elements, the kinetics of redox reactions are controlled by the diffusion of oxygen species. With increasing temperatures, the diffusivities of all ionic species tend to become similar. The decoupling between ionic fluxes then is reduced so that several mechanisms become kinetically equivalent and can thus coexist. (author)

  8. Steam based conversion coating on AA6060 alloy: Effect of sodium silicate chemistry and corrosion performance

    DEFF Research Database (Denmark)

    Din, Rameez Ud; Bordo, Kirill; Tabrizian, Naja

    2017-01-01

    Surface treatment of aluminium alloy AA6060 using an industrially applicable pilot steam jet system with and without silicate chemistry has been investigated. Treatment using steam alone and steam with silicate, resulted in an oxide layer formation with thickness ∼425 nm and ∼160 nm, respectively...

  9. Sodium Silicate Behavior in Porous Media Applied for In-Depth Profile Modifications

    Directory of Open Access Journals (Sweden)

    Hossein A. Akhlaghi Amiri

    2014-03-01

    Full Text Available This paper addresses alkaline sodium silicate (Na-silicate behavior in porous media. One of the advantages of the Na-silicate system is its water-like injectivity during the placement stage. Mixing Na-silicate with saline water results in metal silicate precipitation as well as immediate gelation. This work demonstrated that low salinity water (LSW, sea water diluted 25 times could be used as a pre-flush in flooding operations. A water override phenomenon was observed during gel formation which is caused by gravity segregation. Dynamic adsorption tests in the sand-packed tubes showed inconsiderable adsorbed silicon density (about 8.5 × 10−10 kg/cm3 for a solution with 33 mg/L silicon content, which is less than the estimated mono-layer adsorption density of 1.4 × 10−8 kg/cm3. Na-silicate enhanced water sweep efficiency after application in a dual-permeability sand-pack system, without leak off into the oil-bearing low permeability (LP zone. Field-scale numerical sensitivity studies in a layered reservoir demonstrated that higher permeability and viscosity contrasts and lower vertical/horizontal permeability ratio result in lower Na-silicate leakoff into the matrix. The length of the mixing zone between reservoir water and the injected Na-silicate solution, which is formed by low salinity pre-flush, acts as a buffer zone.

  10. Crystal Structure and Chemical Composition of a Presolar Silicate from the Queen Elizabeth Range 99177 Meteorite

    Science.gov (United States)

    Nguyen, A. N.; Keller, L. P.; Rahman, Z.; Messenger, S.

    2013-01-01

    Mineral characterization of presolar silicate grains, the most abundant stardust phase, has provided valuable information about the formation conditions in circumstellar environments and in super-nova (SN) outflows. Spectroscopic observations of dust around evolved stars suggest a majority of amor-phous, Mg-rich olivine grains, but crystalline silicates, most of which are pyroxene, have also been observed [1]. The chemical compositions of hundreds of presolar silicates have been determined by Auger spectroscopy and reveal high Fe contents and nonstoichiometric compositions intermediate to olivine and pyroxene [2-6]. The unexpectedly high Fe contents can partly be attributed to secondary alteration on the meteorite parent bodies, as some grains have Fe isotopic anomalies from their parent stellar source [7]. Only about 35 presolar silicates have been studied for their mineral structures and chemical compositions by transmission electron microscopy (TEM). These grains display a wide range of compositions and structures, including crystalline forsterite, crystalline pyroxene, nanocrystalline grains, and a majority of amorphous nonstoichiometric grains. Most of these grains were identified in the primitive Acfer 094 meteorite. Presolar silicates from this meteorite show a wide range of Fe-contents, suggestive of secondary processing on the meteorite parent body. The CR chondrite QUE 99177 has not suffered as much alteration [8] and displays the highest presolar silicate abundance to date among carbonaceous chondrites [3, 6]. However, no mineralogical studies of presolar silicates from this meteorite have been performed. Here we examine the mineralogy of a presolar silicate from QUE 99177.

  11. Facile synthesis of magnetic hierarchical copper silicate hollow nanotubes for efficient adsorption and removal of hemoglobin.

    Science.gov (United States)

    Zhang, Min; Wang, Baoyu; Zhang, Yanwei; Li, Weizhen; Gan, Wenjun; Xu, Jingli

    2016-01-21

    This study reports the fabrication of magnetic copper silicate hierarchical hollow nanotubes, which are featured by a tailored complex wall structure and high surface area. Moreover, they exhibit excellent performance as an easily recycled adsorbent for protein separation. Particularly, this strategy can be extended as a general method to prepare other magnetic metal silicate hollow nanotubes.

  12. FT-IR and 29 Si-NMR for evaluating aluminium silicate precursors for geopolymers

    NARCIS (Netherlands)

    Valcke, S.L.A.; Pipilikaki, P.; Fischer, H.R.; Verkuijlen, M.H.W.; Eck, E.R.H.

    2014-01-01

    Geopolymers are systems of inorganic binders that can be used for sustainable, cementless concrete and are formed by alkali activation of an aluminium–silicate precursor (often secondary resources like fly ash or slag). The type of aluminium– silicate precursor and its potential variations within

  13. New estimates of silicate weathering rates and their uncertainties in global rivers

    Science.gov (United States)

    Moon, Seulgi; Chamberlain, C. P.; Hilley, G. E.

    2014-06-01

    This study estimated the catchment- and global-scale weathering rates of silicate rocks from global rivers using global compilation datasets from the GEMS/Water and HYBAM. These datasets include both time-series of chemical concentrations of major elements and synchronous discharge. Using these datasets, we first examined the sources of uncertainties in catchment and global silicate weathering rates. Then, we proposed future sampling strategies and geochemical analyses to estimate accurate silicate weathering rates in global rivers and to reduce uncertainties in their estimates. For catchment silicate weathering rates, we considered uncertainties due to sampling frequency and variability in river discharge, concentration, and attribution of weathering to different chemical sources. Our results showed that uncertainties in catchment-scale silicate weathering rates were due mostly to the variations in discharge and cation fractions from silicate substrates. To calculate unbiased silicate weathering rates accounting for the variations from discharge and concentrations, we suggest that at least 10 and preferably ∼40 temporal chemical data points with synchronous discharge from each river are necessary. For the global silicate weathering rate, we examined uncertainties from infrequent sampling within an individual river, the extrapolation from limited rivers to a global flux, and the inverse model selections for source differentiation. For this weathering rate, we found that the main uncertainty came from the extrapolation to the global flux and the model configurations of source differentiation methods. This suggests that to reduce the uncertainties in the global silicate weathering rates, coverage of synchronous datasets of river chemistry and discharge to rivers from tectonically active regions and volcanic provinces must be extended, and catchment-specific silicate end-members for those rivers must be characterized. With current available synchronous datasets, we

  14. Influence of iron on crystallization behavior and thermal stability of the insulating materials - porous calcium silicates

    DEFF Research Database (Denmark)

    Haastrup, Sonja; Yu, Donghong; Yue, Yuanzheng

    2017-01-01

    The properties of porous calcium silicate for high temperature insulation are strongly influenced by impurities. In this work we determine the influence of Fe3+ on the crystallization behavior and thermal stability of hydrothermally derived calcium silicate. We synthesize porous calcium silicate...... by XRD analysis. The thermal stability and compressive strength of the calcium silicates are seriously influenced by the changes of their crystal structure. Linear shrinkage of the reference sample is 1.3% at 1050°C, whereas the sample with Fe/Si =1.0% does by 30.4%. In conclusion, the presence of Fe3......+ modifies the crystal structure of porous calcium silicates, leading to a significant shrinkage in these materials....

  15. Bioactivity studies of calcium magnesium silicate prepared from eggshell waste by sol–gel combustion synthesis

    Directory of Open Access Journals (Sweden)

    Rajan Choudhary

    2015-06-01

    Full Text Available The present study focused on the synthesis of calcium magnesium silicate (akermanite, Ca2MgSi2O7 using eggshell biowaste (as calcium source, magnesium nitrate and tetraethyl orthosilicate (TEOS as starting materials. Sol–gel combustion method was adopted to obtain calcium magnesium silicate. Citric acid was used as a fuel (reducing agent and nitrate ions present in the metal nitrates acts as an oxidizing agent during combustion process. The characterization of synthesized calcium magnesium silicate was carried out by powder X-ray diffraction (XRD, Fourier transform infrared (FTIR and scanning electron microscopy (SEM techniques. Calcium magnesium silicate crystallite size was observed in nano regime which can effectively mimic natural bone apatite composition. In-vitro bioactivity was investigated by immersing calcium magnesium silicate pellet in simulated body fluid (SBF for three weeks. Results show effective deposition of crystallized hydroxyapatite (HAP layer on its surface and predicting its possibilities for applications in hard tissue regeneration.

  16. Pilot study on binding of bovine salivary proteins to grit silicates and plant phytoliths.

    Science.gov (United States)

    Mau, Marcus; M Kaiser, Thomas; Südekum, Karl-Heinz

    2013-06-01

    Mostly fed with grass in fresh or conserved form, cattle and other livestock have to cope with silicate defence bodies from plants (phytoliths) and environmental silicates (grit), which abrade tooth enamel and could additionally interact with various salivary proteins. To detect potential candidates for silicate-binding proteins, bovine whole saliva was incubated with grass-derived phytoliths and silicates. Interactions of salivary proteins with pulverized bovine dental enamel and dentine were additionally analysed. After intense washing, the powder fractions were loaded onto 1D-polyacrylamide gels, most prominent adhesive protein bands were cut out and proteins were identified by mass spectrometry within three independent replicates. All materials were mainly bound by bovine odorant-binding protein, bovine salivary protein 30×10(3) and carbonic anhydrase VI. The phytolith/silicate fraction showed additional stronger interaction with haemoglobin β and lactoperoxidase. Conceivably, the binding of these proteins to the surfaces may contribute to biological processes occurring on them.

  17. Apatite: a new redox proxy for silicic magmas?

    Science.gov (United States)

    Miles, Andrew; Graham, Colin; Hawkesworth, Chris; Gillespie, Martin; Bromiley, Geoff; Hinton, Richard

    2015-04-01

    The oxidation states of magmas provide valuable information about the release and speciation of volatile elements during volcanic eruptions, metallogenesis, source rock compositions, open system magmatic processes, tectonic settings and potentially titanium (Ti) activity in chemical systems used for Ti-dependent geothermometers and geobarometers. In this presentation we explore the use of Mn in apatite as an oxybarometer in intermediate and silicic igneous rocks. Increased Mn concentrations in apatite in granitic rocks from the zoned Criffell granitic pluton (southern Scotland) correlate with decreasing Fe2O3 (Fe3+) and Mn in the whole-rock and likely reflect increased Mn2+/Mn3+and greater compatibility of Mn2+ relative to Mn3+ in apatite under reduced conditions. Fe3+/Fe2+ ratios in biotites have previously been used to calculate oxygen fugacities (fO2) in the outer zone granodiorites and inner zone granites where redox conditions have been shown to change from close to the magnetite-hematite buffer to close to the nickel-nickel oxide buffer respectively[1]. This trend is apparent in apatite Mn concentrations from a range of intermediate to silicic volcanic rocks that exhibit varying redox states and are shown to vary linearly and negatively with log fO2, such that logfO2=-0.0022(±0.0003)Mn(ppm)-9.75(±0.46) Variations in the Mn concentration of apatites appear to be largely independent of differences in the Mn concentration of the melt. Apatite Mn concentrations may therefore provide an independent oxybarometer that is amenable to experimental calibration, with major relevance to studies on detrital mineral suites, particularly those containing a record of early Earth redox conditions, and on the climatic impact of historic volcanic eruptions[2]. [1] Stephens, W. E., Whitley, J. E., Thirlwall, M. F. and Halliday, A. N. (1985) The Criffell zoned pluton: correlated behaviour of rare earth element abundances with isotopic systems. Contributions to Mineralogy and

  18. Role of organically modified layered silicate both as an active interfacial modifier and nanofiller for immiscible polymer blends.

    CSIR Research Space (South Africa)

    Ray, SS

    2007-05-01

    Full Text Available ) revealed efficient mixing of the polymers in the presence of organically modified layered silicate. X-ray diffraction (XRD) patterns and transmission electron microscopic (TEM) observations showed that silicate layers were either intercalated or exfoliated...

  19. Effects of Silicate, Phosphate, and Calcium on the Stability of Aldopentoses

    Science.gov (United States)

    Nitta, Sakiko; Furukawa, Yoshihiro; Kakegawa, Takeshi

    2016-06-01

    Ribose is an important constituent of RNA: ribose connects RNA bases and forms a strand of sugar phosphates. Accumulation of ribose on prebiotic Earth was difficult because of its low stability. Improvement in the yield of ribose by the introduction of borate or silicate in a formose-like reaction has been proposed. The effects of borates have been further analyzed and confirmed in subsequent studies. Nonetheless, the effects of silicates and phosphates remain unclear. In the present study, we incubated aldopentoses in a highly alkaline aqueous solution at a moderate temperature to determine the effects of silicate or phosphate on the degradation rates of ribose and its isomeric aldopentoses. The formation of a complex of silicate (or phosphate) with ribose was also analyzed in experiments with 29Si and 31P nuclear magnetic resonance (NMR). We found that silicate or phosphate complexes of ribose were not detectable under our experimental conditions. The stability of ribose and lyxose improved after addition of 40-fold molar excess (relative to a pentose) of sodium silicate or sodium phosphate to the alkaline solution. The stability was not improved further when an 80-fold molar excess of sodium silicate or sodium phosphate was added. Calcium was removed from these solutions by precipitation of calcium salts. The drop in Ca2+ concentration might have improved the stability of ribose and lyxose, which are susceptible to aldol addition. The improvement of ribose stability by the removal of Ca2+ and by addition of silicate or phosphate was far smaller than the improvement by borate. Furthermore, all aldopentoses showed similar stability in silicate- and phosphate-containing solutions. These results clearly show that selective stabilization of ribose by borate cannot be replaced by the effects of silicate or phosphate; this finding points to the importance of borate in prebiotic RNA formation.

  20. Measurement of the efficacy of calcium silicate for the protection and repair of dental enamel.

    Science.gov (United States)

    Parker, Alexander S; Patel, Anisha N; Al Botros, Rehab; Snowden, Michael E; McKelvey, Kim; Unwin, Patrick R; Ashcroft, Alexander T; Carvell, Mel; Joiner, Andrew; Peruffo, Massimo

    2014-06-01

    To investigate the formation of hydroxyapatite (HAP) from calcium silicate and the deposition of calcium silicate onto sound and acid eroded enamel surfaces in order to investigate its repair and protective properties. Calcium silicate was mixed with phosphate buffer for seven days and the resulting solids analysed for crystalline phases by Raman spectroscopy. Deposition studies were conducted on bovine enamel surfaces. Acid etched regions were produced on the enamel surfaces using scanning electrochemical cell microscopy (SECCM) with acid filled pipettes and varying contact times. Following treatment with calcium silicate, the deposition was visualised with FE-SEM and etch pit volumes were measured by AFM. A second set of bovine enamel specimens were pre-treated with calcium silicate and fluoride, before acid exposure with the SECCM. The volumes of the resultant acid etched pits were measured using AFM and the intrinsic rate constant for calcium loss was calculated. Raman spectroscopy confirmed that HAP was formed from calcium silicate. Deposition studies demonstrated greater delivery of calcium silicate to acid eroded than sound enamel and that the volume of acid etched enamel pits was significantly reduced following one treatment (penamel was 0.092 ± 0.008 cm/s. This was significantly reduced, 0.056 ± 0.005 cm/s, for the calcium silicate treatments (penamel surfaces. Calcium silicate can provide significant protection of sound enamel from acid challenges. Calcium silicate is a material that has potential for a new approach to the repair of demineralised enamel and the protection of enamel from acid attacks, leading to significant dental hard tissue benefits. © 2014 Elsevier Ltd. All rights reserved.

  1. The europium and praseodymium hydrolysis in a 2M NaCl environment; La hidrolisis del europio y del praseodimio en un medio 2M de NaCl

    Energy Technology Data Exchange (ETDEWEB)

    Jimenez R, M.; Lopez G, H.; Solache R, M.; Rojas H, A. [Instituto Nacional de Investigaciones Nucleares, Departamento de quimica, A.P. 18-1027, 11801 Mexico D.F. (Mexico)

    1998-07-01

    It was studied the europium and praseodymium hydrolysis in a 2M NaCl ion force environment at 303 K, through two methods: this one extraction with dissolvents (lanthanide-water-NaCl-dibenzoylmethane) in presence of a competitive ligand (diglycolic acid) and that one direct potentiometric titration, of soluble species, followed by a computer refining. The values of one or another techniques of the first hydrolysis constants obtained were similar, which demonstrates that the results are reliable. The set of data obtained on the stability constants of hydrolysis products allowed to draw up the distribution diagrams of chemical species, as europium as praseodymium in aqueous environment. (Author)

  2. Soil microbial response to waste potassium silicate drilling fluid.

    Science.gov (United States)

    Yao, Linjun; Naeth, M Anne; Jobson, Allen

    2015-03-01

    Potassium silicate drilling fluids (PSDF) are a waste product of the oil and gas industry with potential for use in land reclamation. Few studies have examined the influence of PSDF on abundance and composition of soil bacteria and fungi. Soils from three representative locations for PSDF application in Alberta, Canada, with clay loam, loam and sand textures were studied with applications of unused, used once and used twice PSDF. For all three soils, applying ≥40 m3/ha of used PSDF significantly affected the existing soil microbial flora. No microbiota was detected in unused PSDF without soil. Adding used PSDF to soil significantly increased total fungal and aerobic bacterial colony forming units in dilution plate counts, and anaerobic denitrifying bacteria numbers in serial growth experiments. Used PSDF altered bacterial and fungal colony forming unit ratios of all three soils. Copyright © 2015. Published by Elsevier B.V.

  3. Laboratory Evidence for Microbially Mediated Silicate Mineral Dissolution in Nature

    Energy Technology Data Exchange (ETDEWEB)

    Ullman, W. J.; Kirchman, D. L.; Welch, S. A.; Vandevivere, P.

    1996-01-01

    Bacteria may potentially enhance or inhibit silicate mineral dissolution in nature by a variety of mechanisms. In the laboratory, some microbial metabolites enhanced dissolution rates by a factor of ten above the expected proton-promoted rate by an additional ligand-promoted mechanism focused principally at Al sites at the mineral surface. In investigations with bacteria, it was found that organic acids are produced in organic-rich/nutrient-poor cultures, resulting in increased mineral dissolution rates compared to abiotic controls. Alginate and poly-aspartate inhibited dissolution rates either by a reduction in surface reactivity or reactive surface area (or both). Bacteria may also influence dissolution rates by creating and maintaining microenvironments where metabolite concentrations are higher than in the bulk solution.

  4. About Fundamental Problems of Hydrosphere and Silicate Karst

    Directory of Open Access Journals (Sweden)

    A. Ya. Gayev

    2017-09-01

    Full Text Available Rationale of hydrosphere model with two regions of supply and discharge reveals regularities of ground water formation reflecting the special features of system water – rock – gas – living material and character of interaction of hydrosphere with the other spheres of the Earth. It is necessary to concentrate the development of endogenous hy-drogeology fundamentals with the study of silicate karst on investigation of “white and black smokers”, the structure and isotope composition of water in different phase condi-tions, and on modeling of situation in hydrometagenese zone. It will support the development of geotechnology and providing the humanity with mineral and energetic resources in future.

  5. Is plant ecology more siliceous than we realise?

    Science.gov (United States)

    Cooke, Julia; Leishman, Michelle R

    2011-02-01

    Although silicon occurs in all plants, it is an element that is largely overlooked by many plant ecologists and most plant-related research on silicon comes from agronomy, archaeology, palaeontology and biogeochemistry. Plant silicon has many functions, acting biochemically as silicic acid and physically as amorphous silica. It contributes to cell and plant strength and enables plants to respond adaptively to environmental stresses. Consequently, plant silicon can increase plant fitness in many fundamental aspects of ecology, including plant-herbivore interactions, light interception, pathogen resistance and alleviation of abiotic stresses. Here, we provide an ecological perspective to research outcomes from diverse disciplines, showing that silicon is an important element in plant ecology that is worthy of greater attention. Copyright © 2010 Elsevier Ltd. All rights reserved.

  6. Intergranular area microalloyed aluminium-silicate ceramics fractal analysis

    Directory of Open Access Journals (Sweden)

    Purenović J.

    2013-01-01

    Full Text Available Porous aluminium-silicate ceramics, modified by alloying with magnesium and microalloying with alluminium belongs to a group of advanced multifunctional ceramics materials. This multiphase solid-solid system has predominantly amorphous microstructure and micro morphology. Intergranular and interphase areas are very complex, because they represent areas, where numbered processes and interactions take place, making new boundaries and regions with fractal nature. Fractal analysis of intergranular microstructure has included determination of ceramic grain fractal dimension by using Richardson method. Considering the fractal nature of intergranular contacts, it is possible to establish correlation between material electrical properties and fractal analysis, as a tool for future correlation with microstructure characterization. [Projekat Ministarstva nauke Republike Srbije, br. ON 172057 i br. III 45012

  7. Stylolites, porosity, depositional texture, and silicates in chalk facies sediments

    DEFF Research Database (Denmark)

    Fabricius, Ida Lykke; Borre, Mai K.

    2007-01-01

    Comparison of chalk on the Ontong Java Plateau and chalk in the Central North Sea indicates that, whereas pressure dissolution is controlled by effective burial stress, pore-filling cementation is controlled by temperature. Effective burial stress is caused by the weight of all overlying water...... and sediments as counteracted by the pressure in the pore fluid, so the regional overpressure in the Central North Sea is one reason why the two localities have different relationships between temperature and effective burial stress. In the chalk of the Ontong Java Plateau the onset of calcite-silicate pressure...... equilibrated to quartz before the onset of pressure dissolution and thus, in this case, dissolution and precipitation of calcite have no lag. This temperature versus effective burial stress induced difference in diagenetic history is of particular relevance when exploring for hydrocarbons in normally pressured...

  8. Tribological properties of silicate materials on nano and microscale

    Energy Technology Data Exchange (ETDEWEB)

    Tordjeman, Ph., E-mail: philippe.tordjeman@imft.fr [Universite de Toulouse-CNRS, Institut de Mecanique des Fluides de Toulouse UMR 5502, Allee Camille Soula, F-31400 Toulouse (France); Morel, N. [Laboratoire IES, Groupe Micro et RheoAcoustique, UMR CNRS 5214, Universite Montpellier 2, CC 082, Pl. E. Bataillon, 34095 Montpellier Cedex 05 (France); Ramonda, M. [Laboratoire de Microscopie a Champ Proche, LMCP, Universite Montpellier 2, CC 082, Pl. E. Bataillon, 34095 Montpellier Cedex 05 (France)

    2009-05-15

    We studied the friction properties of four model silicate materials at the nanoscale and microscale. From nanotribology, we characterized the tribological properties at single asperity contact scale and from microtribology, we characterized the tribological properties at multi asperity contact scale. First, for each material we measured chemical composition by XPS, Young's modulus by acoustical microscopy and roughness {sigma} by atomic force microscopy (AFM). Second, we measured the nanofriction coefficients with an AFM and the microfriction coefficients with a ball probe tribometer, for three hardnesses of the ball probe. We identified one friction mechanism at the nanoscale (sliding friction) and two friction mechanisms at the microscale (sliding friction and yielding friction). Comparison of the nano and microfriction coefficients at the same sliding friction regime shown, that the tribological properties of these materials didn't depend on roughness.

  9. High-dose dosimetry using natural silicate minerals

    Energy Technology Data Exchange (ETDEWEB)

    Carmo, Lucas S. do; Mendes, Leticia, E-mail: isatiro@usp.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Watanabe, Shigueo; Rao, Gundu; Lucas, Natasha; Sato, Karina, E-mail: lacifid@if.usp.br [Universidade de Sao Paulo (USP), Sao Paulo, SP (Brazil). Instituto de Fisica. Departamento de Fisica Nuclear; Barbosa, Renata F., E-mail: profcelta@hotmail.com [Universidade Federal de Sao Paulo (UNIFESP), Santos, SP (Brazil). Departamento de Ciencias do Mar

    2015-07-01

    In the present study, certain natural silicate minerals such as aquamarine (AB), morganite (PB), goshenite (WB), white jadeite (JW), green jadeite (JG), pink tourmaline (PT) and two varieties of jadeite-like quartz, denoted here by JQ1 and JQ2, were investigated using the thermoluminescence technique to evaluate their potential for use as very-high- and high-dose dosimeters. These minerals respond to high doses of γ-rays of up to 1000 kGy and often to very high doses of up to 3000 kGy. The TL response of these minerals may be considered to be satisfactory for applications in high-dose dosimetry. Investigations of electron paramagnetic resonance and optically stimulated luminescence dosimetry are in progress. (author)

  10. Luminescent solar concentrators using uranyl-doped silicate glasses

    Science.gov (United States)

    Folcher, G.; Keller, N.; Paris, J.

    1984-09-01

    The effect of the uranium concentration on the performance of uranyl-doped glass used in solar concentrators was examined experimentally. Na-Ca silicate glass and UO3 additive were prepared at 1250 C, cooled to 600 C, annealed at 700 C, and cooled to ambient for the tests. Light absorption was proportional to uranium content up to a 2 percent concentration. A doped-glass test cell filled with a fluoresceine solution and irradiated at 337 nm and 420 nm with laser light was monitored to measure the luminescent lifetimes of the uranyl ions. A 380 microsec half-lifetime was determined, along with a quantum yield that varied from 0.5 at 1 percent uranyl concentration to 0.3 at a 5 percent concentration. The quantum efficiencies could be attained with 1 cm thick glass with existing manufacturing technologies, and thinner glass with further developments.

  11. A-thermal elastic behavior of silicate glasses

    Science.gov (United States)

    Rabia, Mohammed Kamel; Degioanni, Simon; Martinet, Christine; Le Brusq, Jacques; Champagnon, Bernard; Vouagner, Dominique

    2016-02-01

    Depending on the composition of silicate glasses, their elastic moduli can increase or decrease as function of the temperature. Studying the Brillouin frequency shift of these glasses versus temperature allows the a-thermal composition corresponding to an intermediate glass to be determined. In an intermediate glass, the elastic moduli are independent of the temperature over a large temperature range. For sodium alumino-silicate glasses, the a-thermal composition is close to the albite glass (NaAlSi3O8). The structural origin of this property is studied by in situ high temperature Raman scattering. The structure of the intermediate albite glass and of silica are compared at different temperatures between room temperature and 600 °C. When the temperature increases, it is shown that the high frequency shift of the main band at 440 cm-1 in silica is a consequence of the cristobalite-like alpha-beta transformation of 6-membered rings. This effect is stronger in silica than bond elongation (anharmonic effects). As a consequence, the elastic moduli of silica increase as the temperature increases. In the albite glass, the substitution of 25% of Si4+ ions by Al3+ and Na+ ions decreases the proportion of SiO2 6-membered rings responsible for the silica anomaly. The effects of the silica anomaly balance the anharmonicity in albite glass and give rise to an intermediate a-thermal glass. Different networks, formers or modifiers, can be added to produce different a-thermal glasses with useful mechanical or chemical properties.

  12. Evaluation of apatite silicates as solid oxide fuel cell electrolytes

    Energy Technology Data Exchange (ETDEWEB)

    Marrero-Lopez, D. [Dpto. de Fisica Aplicada I, Laboratorio de Materiales y Superficies (Unidad Asociada al C.S.I.C.), Universidad de Malaga, 29071 Malaga (Spain); Dpto. de Quimica Inorganica, Universidad de La Laguna, 38200 La Laguna, Tenerife (Spain); Martin-Sedeno, M.C.; Aranda, M.A.G. [Dpto. de Quimica Inorganica, Universidad Malaga, 29071 Malaga (Spain); Pena-Martinez, J. [Dpto. de Quimica Inorganica, Universidad de La Laguna, 38200 La Laguna, Tenerife (Spain); Instituto de Energias Renovables, Parque Tecnologico, Universidad de Castilla La Mancha, 02006 Albacete (Spain); Ruiz-Morales, J.C.; Nunez, P. [Dpto. de Quimica Inorganica, Universidad de La Laguna, 38200 La Laguna, Tenerife (Spain); Ramos-Barrado, J.R. [Dpto. de Fisica Aplicada I, Laboratorio de Materiales y Superficies (Unidad Asociada al C.S.I.C.), Universidad de Malaga, 29071 Malaga (Spain)

    2010-05-01

    Apatite-type silicates have been considered as promising electrolytes for Solid Oxide Fuel Cells (SOFC); however studies on the potential use of these materials in SOFC devices have received relatively little attention. The lanthanum silicate with composition La{sub 10}Si{sub 5.5}Al{sub 0.5}O{sub 26.75} has been evaluated as electrolyte with the electrode materials commonly used in SOFC, i.e. manganite, ferrite and cobaltite as cathode materials and NiO-CGO composite, chromium-manganite and Sr{sub 2}MgMoO{sub 6} as anode materials. Chemical compatibility, area-specific resistance and fuel cell studies have been performed. X-ray powder diffraction (XRPD) analysis did not reveal any trace of reaction products between the apatite electrolyte and most of the aforementioned electrode materials. However, the area-specific polarisation resistance (ASR) of these electrodes in contact with apatite electrolyte increased significantly with the sintering temperature, indicating reactivity at the electrolyte/electrode interface. On the other hand, the ASR values are significantly improved using a ceria buffer layer between the electrolyte and electrode materials to prevent reactivity. Maximum power densities of 195 and 65 mWcm{sup -2} were obtained at 850 and 700 C, respectively in H{sub 2} fuel, using an 1 mm-thick electrolyte, a NiO-Ce{sub 0.8}Gd{sub 0.2}O{sub 1.9} composite as anode and La{sub 0.6}Sr{sub 0.4}Co{sub 0.8}Fe{sub 0.2}O{sub 3-{delta}} as cathode materials. This fuel cell was tested for 100 h in 5%H{sub 2}-Ar atmosphere showing stable performance. (author)

  13. Low Velocity Sphere Impact of a Soda Lime Silicate Glass

    Energy Technology Data Exchange (ETDEWEB)

    Wereszczak, Andrew A [ORNL; Fox, Ethan E [ORNL; Morrissey, Timothy G [ORNL; Vuono, Daniel J [ORNL

    2011-10-01

    This report summarizes TARDEC-sponsored work at Oak Ridge National Laboratory (ORNL) during the FY11 involving low velocity (< 30 m/s or < 65 mph) ball impact testing of Starphire soda lime silicate glass. The intent was to better understand low velocity impact response in the Starphire for sphere densities that bracketed that of rock. Five sphere materials were used: borosilicate glass, soda-lime silicate glass, steel, silicon nitride, and alumina. A gas gun was fabricated to produce controlled velocity delivery of the spheres against Starphire tile targets. Minimum impact velocities to initiate fracture in the Starphire were measured and interpreted in context to the kinetic energy of impact and the elastic property mismatch between the any of the five sphere-Starphire-target combinations. The primary observations from this low velocity (< 30 m/s or < 65 mph) testing were: (1) Frictional effects contribute to fracture initiation. (2) Spheres with a lower elastic modulus require less force to initiate fracture in the Starphire than spheres with a higher elastic modulus. (3) Contact-induced fracture did not initiate in the Starphire SLS for impact kinetic energies < 150 mJ. Fracture sometimes initiated or kinetic energies between {approx} 150-1100 mJ; however, it tended to occur when lower elastic modulus spheres were impacting it. Contact-induced fracture would always occur for impact energies > 1100 mJ. (4) The force necessary to initiate contact-induced fracture is higher under dynamic or impact conditions than it is under quasi-static indentation conditions. (5) Among the five used sphere materials, silicon nitride was the closest match to 'rock' in terms of both density and (probably) elastic modulus.

  14. In vitro cytotoxicity of calcium silicate-containing endodontic sealers.

    Science.gov (United States)

    Zhou, Hui-min; Du, Tian-feng; Shen, Ya; Wang, Zhe-jun; Zheng, Yu-feng; Haapasalo, Markus

    2015-01-01

    The cytotoxicity of 2 novel calcium silicate-containing endodontic sealers to human gingival fibroblasts was studied. EndoSequence BC (Brasseler, Savannah, GA), MTA Fillapex (Angelus Indústria de Produtos Odontológicos S/A, Londrina, PR, Brazil) and a control sealer (AH Plus; Dentsply DeTrey GmbH, Konstanz, Germany) were evaluated. Human gingival fibroblasts were incubated for 3 days both with the extracts from fresh and set materials in culture medium and cultured on the surface of the set materials in Dulbecco-modified Eagle medium. Fibroblasts cultured in Dulbecco-modified Eagle medium were used as a control group. Cytotoxicity was evaluated by flow cytometry, and the adhesion of the fibroblasts to the surface of the set materials was assessed using scanning electron microscopy. The data of cell cytotoxicity were analyzed statistically using a 1-way analysis of variance test at a significance level of P extracts from BC Sealer showed higher viabilities at all extract concentrations than cells incubated with extracts from freshly mixed AH Plus and fresh and set MTA Fillapex, esspecially for the high extract concentrations (1:2 and 1:8 dilutions). Extracts from set MTA Fillapex of 2 weeks and older were more cytotoxic than extracts from freshly mixed and 1-week-old cement. With extract concentrations of 1:32 and lower, MTA Fillapex was no longer cytotoxic. After setting, AH Plus was no longer cytotoxic, and the fibroblast cells grew on set AH Plus equally as well as on BC Sealer. BC Sealer and MTA Fillapex, the 2 calcium silicate-containing endodontic sealers, exhibited different cytotoxicity to human gingival fibroblasts. Copyright © 2015 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  15. Modified tricalcium silicate cement formulations with added zirconium oxide.

    Science.gov (United States)

    Li, Xin; Yoshihara, Kumiko; De Munck, Jan; Cokic, Stevan; Pongprueksa, Pong; Putzeys, Eveline; Pedano, Mariano; Chen, Zhi; Van Landuyt, Kirsten; Van Meerbeek, Bart

    2017-04-01

    This study aims to investigate the effect of modifying tricalcium silicate (TCS) cements on three key properties by adding ZrO 2 . TCS powders were prepared by adding ZrO 2 at six different concentrations. The powders were mixed with 1 M CaCl 2 solution at a 3:1 weight ratio. Biodentine (contains 5 wt.% ZrO 2 ) served as control. To evaluate the potential effect on mechanical properties, the mini-fracture toughness (mini-FT) was measured. Regarding bioactivity, Ca release was assessed using ICP-AES. The component distribution within the cement matrix was evaluated by Feg-SEM/EPMA. Cytotoxicity was assessed using an XTT assay. Adding ZrO 2 to TCS did not alter the mini-FT (p = 0.52), which remained in range of that of Biodentine (p = 0.31). Ca release from TSC cements was slightly lower than that from Biodentine at 1 day (p > 0.05). After 1 week, Ca release from TCS 30 and TCS 50 increased to a level that was significantly higher than that from Biodentine (p  0.05). EPMA revealed a more even distribution of ZrO 2 within the TCS cements. Particles with an un-reacted core were surrounded by a hydration zone. The 24-, 48-, and 72-h extracts of TCS 50 were the least cytotoxic. ZrO 2 can be added to TCS without affecting the mini-FT; Ca release was reduced initially, to reach a prolonged release thereafter; adding ZrO 2 made TCS cements more biocompatible. TCS 50 is a promising cement formulation to serve as a biocompatible hydraulic calcium silicate cement.

  16. A carbonate-silicate aqueous geochemical cycle model for Mars

    Science.gov (United States)

    Schaefer, M. W.; Leidecker, H.

    1992-01-01

    A model for the carbonate-silicate geochemical cycle of an early, wet Mars is under development. The results of this study will be used to constrain models of the geochemical history of Mars and the likely mineralogy of its present surface. Although Mars today is a cold, dry planet, it may once have been much warmer and wetter. Values of total outgassed CO2 from several to about 10 bars are consistent with present knowledge (Pollack et al. 1987), and this amount of CO2 implies an amount of water outgassed at least equal to an equivalent depth of 500-1000 meters (Carr 1986). Pollack et al. (1987), in addition, estimate that a thick CO2 atmosphere may have existed for an extended period of time, perhaps as long as a billion years. The greenhouse effect of such an atmosphere would permit the presence of liquid water on the surface, most likely in the form of a shallow sea in the lowest regions of the planet, such as the northern plains (Schaefer 1990). The treatment of geochemical cycles as complex kinetic chemical reactions has been undertaken for terrestrial systems in recent years with much success (Lasaga 1980, 1981; Berner et al. 1983; Lasaga et al. 1985). Although the Martian system is vastly less well understood, and hence less well-constrained, it is also a much simpler system, due to the lack of biogenic reactions that make the terrestrial system so complex. It should be possible, therefore, to use the same techniques to model the Martian system as have been used for terrestrial systems, and to produce useful results. A diagram of the carbonate-silicate cycle for Mars (simplified from the terrestrial system) is given.

  17. Fluorine in silicate glasses: A multinuclear nuclear magnetic resonance study

    Energy Technology Data Exchange (ETDEWEB)

    Schaller, T.; Dingwell, D.B.; Keppler, H.; Merwin, L.; Sebald, A. (Univ. Bayreuth (West Germany)); Knoeller, W. (Bruker Analytische Messtechnik, Rheinstetten (West Germany))

    1992-02-01

    Anhydrous nepheline, jadeite, and albite glasses doped with F as well as hydrous F-containing haplogranitic glasses were investigated using {sup 19}F combined rotation and multiple-pulse spectroscopy; {sup 19}F {yields} {sup 29}Si cross-polarization/magic angle spinning (MAS); and high-power {sup 19}F decoupled {sup 29}Si, {sup 23}Na, and {sup 27}Al MAS nuclear magnetic resonance methods. Fluorine preferentially coordinates with Al to form octahedral AlF{sub 6}{sup 3{minus}} complexes in all glasses studied. In addition, F anions bridging two Al cations, units containing octahedral Al coordinated by both O and F, or tetrahedral Al-F complexes might be present. The presence of Si-F bonds cannot be entirely ruled out but appears unlikely on the basis of the {sup 19}F {yields} {sup 29}Si CP/MAS spectra. There is no evidence for any significant coordination of F with alkalis in the glasses studied. Over the range of F contents studied (up to 5 wt.%), there seems to be hardly any dependence of F speciation on the concentration of F in the samples. The spectroscopic results explain the decrease of the viscosity of silicate melts with increasing F content by removal of Al from bridging AlO{sub 4}-units due to complexing with F, which causes depolymerization of the melt. The same mechanism can account for the shift of the eutectic point in the haplogranite system to more feldspar-rich compositions with increasing F content, and for the peraluminous composition of most F-rich granites. Liquid immiscibility in F-rich granitic melts might be caused by formation of (Na,K){sub 3}AlF{sub 6} units in the melt with little or no interaction with the silicate component. The presence of F in granitic melts might increase the solubility of high field strength cations by making nonbridging O atoms available which form complexes with these cations.

  18. Specific chiral sensing of amino acids using induced circularly polarized luminescence of bis(diimine)dicarboxylic acid europium(III) complexes.

    Science.gov (United States)

    Okutani, Kazuhiro; Nozaki, Koichi; Iwamura, Munetaka

    2014-06-02

    The circularly polarized luminescence (CPL) from [Eu(pda)2](-) (pda = 1,10-phenanthroline-2,9-dicarboxylic acid) and [Eu(bda)2](-) (bda = 2,2'-bipyridine-6,6'-dicarboxylic acid) in aqueous solutions containing various amino acids was investigated. The europium(III) complexes exhibited bright-red luminescence assignable to the f-f transition of the Eu(III) ion when irradiated with UV light. Although the luminescence was not circularly polarized in the solid state or in aqueous solutions, in accordance with the achiral crystal structure, the complexes exhibited detectable induced CPL (iCPL) in aqueous solutions containing chiral amino acids. In the presence of L-pyrrolidonecarboxylic acid, both [Eu(pda)2](-) and [Eu(bda)2](-) showed similar iCPL intensity (glum ∼ 0.03 for the (5)D0 → (7)F1 transition at 1 mol·dm(-3) of the amino acid). On the other hand, in the presence of L-histidine or L-arginine, [Eu(pda)2](-) exhibited intense CPL (glum ∼ 0.08 for the (5)D0 → (7)F1 transition at 0.10 mol·dm(-3) of the amino acid), whereas quite weak CPL was observed for [Eu(bda)2](-) under the same conditions (glum europium(III) complexes possess coordination structures similar to that in the crystal with slight distortion to form a chiral structure due to specific interaction with two zwitterionic amino acids. This mechanism was in stark contrast to that of the europium(III) complex-pyrrolidonecarboxylic acid system in which one amino acid coordinates to the Eu(III) ion to yield an achiral coordination structure.

  19. A convenient method for europium-labeling of a recombinant chimeric relaxin family peptide R3/I5 for receptor-binding assays.

    Science.gov (United States)

    Zhang, Wei-Jie; Jiang, Qian; Wang, Xin-Yi; Song, Ge; Shao, Xiao-Xia; Guo, Zhan-Yun

    2013-06-01

    Relaxin family peptides have important biological functions, and so far, four G-protein-coupled receptors have been identified as their receptors (RXFP1-4). A chimeric relaxin family peptide R3/I5, containing the B-chain of relaxin-3 and the A-chain of INSL5, is a selective agonist for both RXFP3 and RXFP4. In a previous study, europium-labeled R3/I5, as a nonradioactive and low-background receptor-binding tracer, was prepared through a chemical synthesis approach. In the present study, we established a convenient alternative approach for preparing the europium-labeled R3/I5 tracer based on a recombinant R3/I5 designed to carry a solubilizing tag at the A-chain N-terminus and a pyroglutamate residue at the B-chain N-terminus. Because of the presence of a single primary amine moiety, the recombinant R3/I5 peptide was site-specifically mono-labeled at the A-chain N-terminus by a diethylenetriaminepentaacetic acid/europium moiety through a convenient one-step procedure. The diethylenetriaminepentaacetic acid/Eu3+-labeled R3/I5 bound both receptors RXFP3 and RXFP4 with high binding affinities and low nonspecific binding. Thus, we have presented a valuable nonradioactive tracer for future interaction studies on RXFP3 and RXFP4 with various natural or designed ligands. The present approach could also be adapted for preparing and labeling of other chimeric relaxin family peptides. Copyright © 2013 European Peptide Society and John Wiley & Sons, Ltd.

  20. Europium-activated phosphors containing oxides of rare-earth and group-IIIB metals and method of making the same

    Science.gov (United States)

    Comanzo, Holly Ann; Setlur, Anant Achyut; Srivastava, Alok Mani; Manivannan, Venkatesan

    2004-07-13

    Europium-activated phosphors comprise oxides of at least a rare-earth metal selected from the group consisting of gadolinium, yttrium, lanthanum, and combinations thereof and at least a Group-IIIB metal selected from the group consisting of aluminum, gallium, indium, and combinations thereof. A method for making such phosphors comprises adding at least a halide of at least one of the selected Group-IIIB metals in a starting mixture. The method further comprises firing the starting mixture in an oxygen-containing atmosphere. The phosphors produced by such a method exhibit improved absorption in the UV wavelength range and improved quantum efficiency.

  1. Synthesis and pharmacological characterization of a europium-labelled single-chain antagonist for binding studies of the relaxin-3 receptor RXFP3.

    Science.gov (United States)

    Haugaard-Kedström, Linda M; Wong, Lilian L L; Bathgate, Ross A D; Rosengren, K Johan

    2015-06-01

    Relaxin-3 and its endogenous receptor RXFP3 are involved in fundamental neurological signalling pathways, such as learning and memory, stress, feeding and addictive behaviour. Consequently, this signalling system has emerged as an attractive drug target. Development of leads targeting RXFP3 relies on assays for screening and ligand optimization. Here, we present the synthesis and in vitro characterization of a fluorescent europium-labelled antagonist of RXFP3. This ligand represents a cheap and safe but powerful tool for future mechanistic and cell-based receptor-ligand interaction studies of the RXFP3 receptor.

  2. Bis{[6-methoxy-2-(4-methylphenyliminiomethyl]phenolate-κ2O,O′}tris(nitrato-κ2O,O′europium(III

    Directory of Open Access Journals (Sweden)

    Hang-Ming Guo

    2010-11-01

    Full Text Available The crystal structure of title compound, [Eu(NO33(C15H15NO22], contains two Schiff base 6-methoxy-2-[(4-methylphenyliminomethyl]phenolate (L ligands and three independent nitrate ions that chelate to the europium(III ion via the O atoms. The coordination number of the EuIII ion is ten. The L ligands chelate with a strong Eu—O(deprotonated phenolate bond and a weak Eu—O(methoxy contact, the latter can be interpreted as the apices of the bicapped square-antiprismatic EuIII polyhedron. Intramolecular N—H...O hydrogen bonds occur.

  3. Relationships between CO2, thermodynamic limits on silicate weathering, and the strength of the silicate weathering feedback

    Science.gov (United States)

    Winnick, Matthew J.; Maher, Kate

    2018-03-01

    Recent studies have suggested that thermodynamic limitations on chemical weathering rates exert a first-order control on riverine solute fluxes and by extension, global chemical weathering rates. As such, these limitations may play a prominent role in the regulation of carbon dioxide levels (pCO2) over geologic timescales by constraining the maximum global weathering flux. In this study, we develop a theoretical scaling relationship between equilibrium solute concentrations and pCO2 based on equilibrium constants and reaction stoichiometry relating primary mineral dissolution and secondary mineral precipitation. We test this theoretical scaling relationship against reactive transport simulations of chemical weathering profiles under open- and closed-system conditions, representing partially and fully water-saturated regolith, respectively. Under open-system conditions, equilibrium bicarbonate concentrations vary as a power-law function of pCO2 (y = kxn) where n is dependent on reaction stoichiometry and k is dependent on both reaction stoichiometry and the equilibrium constant. Under closed-system conditions, bicarbonate concentrations vary linearly with pCO2 at low values and approach open-system scaling at high pCO2. To describe the potential role of thermodynamic limitations in the global silicate weathering feedback, we develop a new mathematical framework to assess weathering feedback strength in terms of both (1) steady-state atmospheric pCO2 concentrations, and (2) susceptibility to secular changes in degassing rates and transient carbon cycle perturbations, which we term 1st and 2nd order feedback strength, respectively. Finally, we discuss the implications of these results for the effects of vascular land plant evolution on feedback strength, the potential role of vegetation in controlling modern solute fluxes, and the application of these frameworks to a more complete functional description of the silicate weathering feedback. Most notably, the dependence

  4. A design of spectrophotometric microfluidic chip sensor for analyzing silicate in seawater

    Science.gov (United States)

    Cao, X.; Zhang, S. W.; Chu, D. Z.; Wu, N.; Ma, H. K.; Liu, Y.

    2017-08-01

    High quality and continuous in situ silicate data are required to investigate the mechanism of the biogeochemical cycles and the formation of red tide. There is an urgently growing need for autonomous in situ silicate instruments that perform determination on various platforms. However, due to the high reagents and power consumption, as well as high system complexity leading to low reliability and robustness, the performance of the commercially available silicate sensors is not satisfactory. With these problems, here we present a new generation of microfluidic continuous flow analysis silicate sensor with sufficient analytical performance and robustness, for in situ determination of soluble silicate in seawater. The reaction mechanism of this sensor is based on the reaction of silicate with ammonium molybdate to form a yellow silicomolybdate complex and further reduction to silicomoIybdenum blue by ascorbic acid. The minimum limit of detection was 45.1 nmol L-1, and the linear determination range of the sensor is 0-400 μmol L-1. The recovery rate of the actual water is between 98.1%-104.0%, and the analyzing cycle of the sensor is about 5 minutes. This sensor has the advantages of high accuracy, high integration, low water consumption, and strong anti-interference ability. It has been successfully applied to measuring the silicate in seawater in Jiaozhou Bay.

  5. Petrophysical Analysis of Siliceous-Ooze Sediments, More Basin, Norwegian Sea

    DEFF Research Database (Denmark)

    Awedalkarim, Ahmed; Sørensen, Morten Kanne; Fabricius, Ida Lykke

    2014-01-01

    Pelagic siliceous-ooze sediments occur above the hydrocarbon reservoir of the Ormen Lange gas field in More Basin, Norwegian Sea. A possible hydrocarbon prospect of siliceous ooze was proposed, but siliceous ooze is significantly different in texture from most commonly known reservoir rocks. Logg....... Amplitude-versus-offset analysis indicated that an oil-saturated sandstone layer can be distinguished from water-saturated siliceous ooze.......Pelagic siliceous-ooze sediments occur above the hydrocarbon reservoir of the Ormen Lange gas field in More Basin, Norwegian Sea. A possible hydrocarbon prospect of siliceous ooze was proposed, but siliceous ooze is significantly different in texture from most commonly known reservoir rocks...... was calculated from the gamma-ray log and empirical grain-density data were calibrated with X-ray diffraction analysis data. The grain-density log was used with the calculated true porosity log and the brine density of 1.025 g/cm(3) to convert the bulk-density log from conventional limestone and water scaling...

  6. Evaluation of the effect of sodium silicate addition to mine backfill, Gelfill − Part 1

    Directory of Open Access Journals (Sweden)

    M. Kermani

    2015-06-01

    Full Text Available In this paper, the mechanical properties of sodium silicate-fortified backfill, called Gelfill, were investigated by conducting a series of laboratory experiments. Two configurations were tested, i.e. Gelfill and cemented hydraulic fill (CHF. The Gelfill has an alkali activator such as sodium silicate in its materials in addition to primary materials of mine backfill which are tailings, water and binders. Large numbers of samples of Gelfill and CHF with various mixture designs were cast and cured for over 28 d. The mechanical properties of samples were investigated using uniaxial compression test, and the results were compared with those of reference samples made without sodium silicate. The test results indicated that the addition of an appropriate amount of an alkali activator such as sodium silicate can enhance the mechanical (uniaxial compressive strength and physical (water retention properties of backfill. The microstructure analysis conducted by mercury intrusion porosimetry (MIP revealed that the addition of sodium silicate can modify the pore size distribution and total porosity of Gelfill, which can contribute to the better mechanical properties of Gelfill. It was also shown that the time and rate of drainage in the Gelfill specimens are less than those in CHF specimens made without sodium silicate. Finally, the study showed that the addition of sodium silicate can reduce the required setting time of mine backfill, which can contribute to increase mine production in accordance with the mine safety.

  7. Bilateral urinary calculi after treatment with a silicate-containing milk thickener.

    Science.gov (United States)

    Ulinski, Tim; Sabot, Jean-François; Bourlon, Isabelle; Cochat, Pierre

    2004-04-01

    Nephrocalcinosis and/or urinary calculi are rare in infants. Furosemide treatment during the neonatal period, vitamin D intoxication, hereditary diseases such as hyperoxaluria or distal tubular acidosis are among the most common aetiologies. We report the case of a 6-month-old boy with an extra-hepatic biliary duct atresia treated by the Kasai procedure and a gastro-oesophageal reflux treated with a silicate containing milk thickener (Gelopectose, 5.5% colloidal silicate) since the neonatal period. He did not present any other endogenous risk factor for urinary stone formation (normal urinary calcium/creatinine ratio; normal urinary magnesium excretion). The nephrolithiasis was discovered as the boy presented painful episodes of macroscopic haematuria. Ultrasound examination revealed bilateral nephrocalcinosis and multiple bilateral calculi without infection or urinary obstruction. Infrared spectroscopy revealed silicate as the major component suggesting silicate absorption to be responsible for the described symptoms. After replacement of the silicate-containing agent by a silicate-free milk thickener, the lesions were completely reversible as confirmed by repeated renal ultrasound examinations over a 2-month period. Silicate-containing milk thickeners can be responsible for urinary calculi and/or nephrocalcinosis.

  8. Preparation and Characterization of Lithium Zirconium Silicate for CO2 Capture

    Directory of Open Access Journals (Sweden)

    T.S. Bhosale

    2014-10-01

    Full Text Available The samples of lithium zirconium silicate were prepared by precipitation, template and sol-gel meth-ods. The samples were prepared with several mol ratios of Li:Zr:Si. The preparation of lithium zirco-nium silicate samples by precipitation method were carried out by using the lithium nitrate, zirconyl nitrate, zirconium(IV oxypropoxide and tetramethylorthosilicate (TEOS as precursors. The samples of lithium zirconium silicate were prepared by using cetyltrimethyl-ammonium bromide (C-TAB and tetramethyl ammonium hydroxide (TMAOH by template method. The samples of lithium zirconium silicate were characterized by XRD, TEM, SEM, 29Si-MAS NMR and FTIR. The surface area, alkalinity / acidity of the samples of lithium zirconium silicate were measured. The TGA analysis of lithium zirco-nium silicate samples was done. The CO2 captured by the samples of lithium zirconium silicate was es-timated. The captured CO2 by the samples of lithium zirconium silicate was found to be in the range 3.3 to 8.6 wt%. © 2014 BCREC UNDIP. All rights reservedReceived: 27th March 2014; Revised: 31st July 2014; Accepted: 2nd August 2014How to Cite: Bhosale, T.S. , Gaikwad, A.G. (2014. Preparation and Characterization of Lithium Zirconium Silicate for CO2 Capture. Bulletin of Chemical Reaction Engineering & Catalysis, 9(3: 249-262. (doi:10.9767/bcrec.9.3.6646.249-262Permalink/DOI: http://dx.doi.org/10.9767/bcrec.9.3.6646.249-262

  9. Sulfur Saturation Limits in Silicate Melts and their Implications for Core Formation Scenarios for Terrestrial Planets

    Science.gov (United States)

    Holzheid, Astrid; Grove, Timothy L.

    2002-01-01

    This study explores the controls of temperature, pressure, and silicate melt composition on S solubility in silicate liquids. The solubility of S in FeO-containing silicate melts in equilibrium with metal sulfide increases significantly with increasing temperature but decreases with increasing pressure. The silicate melt structure also exercises a control on S solubility. Increasing the degree of polymerization of the silicate melt structure lowers the S solubility in the silicate liquid. The new set of experimental data is used to expand the model of Mavrogenes and O'Neill(1999) for S solubility in silicate liquids by incorporating the influence of the silicate melt structure. The expected S solubility in the ascending magma is calculated using the expanded model. Because the negative pressure dependence of S solubility is more influential than the positive temperature dependence, decompression and adiabatic ascent of a formerly S-saturated silicate magma will lead to S undersaturation. A primitive magma that is S-saturated in its source region will, therefore, become S-undersaturated as it ascends to shallower depth. In order to precipitate magmatic sulfides, the magma must first cool and undergo fractional crystallization to reach S saturation. The S content in a metallic liquid that is in equilibrium with a magma ocean that contains approx. 200 ppm S (i.e., Earth's bulk mantle S content) ranges from 5.5 to 12 wt% S. This range of S values encompasses the amount of S (9 to 12 wt%) that would be present in the outer core if S is the light element. Thus, the Earth's proto-mantle could be in equilibrium (in terms of the preserved S abundance) with a core-forming metallic phase.

  10. Carbon footprint assessment of recycling technologies for rare earth elements: A case study of recycling yttrium and europium from phosphor.

    Science.gov (United States)

    Hu, Allen H; Kuo, Chien-Hung; Huang, Lance H; Su, Chao-Chin

    2017-02-01

    Rare earth elements are key raw materials in high-technology industries. Mining activities and manufacturing processes of such industries have caused considerable environmental impacts, such as soil erosion, vegetation destruction, and various forms of pollution. Sustaining the long-term supply of rare earth elements is difficult because of the global shortage of rare earth resources. The diminishing supply of rare earth elements has attracted considerable concern because many industrialized countries regarded such elements as important strategic resources for economic growth. This study aims to explore the carbon footprints of yttrium and europium recovery techniques from phosphor. Two extraction recovery methods, namely, acid extraction and solvent extraction, were selected for the analysis and comparison of carbon footprints. The two following functional units were used: (1) the same phosphor amounts for specific Y and Eu recovery concentrations, and (2) the same phosphor amounts for extraction. For acid extraction method, two acidic solutions (H2SO4 and HCl) were used at two different temperatures (60 and 90°C). For solvent extraction method, acid leaching was performed followed by ionic liquid extraction. Carbon footprints from acid and solvent extraction methods were estimated to be 10.1 and 10.6kgCO2eq, respectively. Comparison of the carbon emissions of the two extraction methods shows that the solvent extraction method has significantly higher extraction efficiency, even though acid extraction method has a lower carbon footprint. These results may be used to develop strategies for life cycle management of rare earth resources to realize sustainable usage. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. Evaluation of in vivo cytogenetic toxicity of europium hydroxide nanorods (EHNs) in male and female Swiss albino mice.

    Science.gov (United States)

    Bollu, Vishnu Sravan; Nethi, Susheel Kumar; Dasari, Rama Krishna; Rao, Soma Shiva Nageshwara; Misra, Sunil; Patra, Chitta Ranjan

    2016-01-01

    Our group already demonstrated that europium hydroxide nanorods (EHNs) show none or mild toxicity in C57BL/6 mice even at high dose and exhibited excellent pro-angiogenic activity towards in vitro and in vivo models. In the present study, we evaluated the in vivo cytogenetic toxicity of intraperitoneally administered EHNs (12.5-250 mg/kg/b.w.) in male and female Swiss albino mice by analyzing chromosomal aberrations (CAs), mitotic index (MI), micronucleus (MN) from bone marrow and peripheral blood. Furthermore, we performed the cytogenetic toxicity study of EHNs towards Chinese hamster ovary (CHO) cells, in order to compare with the in vivo results. The results of CA assay of mice treated with EHNs (12.5-125 mg/kg/b.w.) showed no significant change in the formation of aberrant metaphases compared to the control group. Also, there was no significant difference in the number of dividing cells between the control group and EHNs-treated groups observed by MI study, suggesting the non-cytotoxicity of EHNs. Additionally, FACS study revealed that EHNs do not arrest cells at any phase of cell cycle in the mouse model. Furthermore, MN test of both bone marrow and peripheral blood showed no significant differences in the induction of MNs when compared with the control group. In vitro results from CHO cells also support our in vivo observations. Considering the role of angiogenesis by EHNs and the absence of its genotoxicity in mouse model, we strongly believe the future application of EHNs in treating various diseases, where angiogenesis plays an important role such as cardiovascular diseases, ischemic diseases and wound healing.

  12. Pockels effect of silicate glass-ceramics: Observation of optical modulation in Mach-Zehnder system.

    Science.gov (United States)

    Yamaoka, Kazuki; Takahashi, Yoshihiro; Yamazaki, Yoshiki; Terakado, Nobuaki; Miyazaki, Takamichi; Fujiwara, Takumi

    2015-07-17

    Silicate glass has been used for long time because of its advantages from material's viewpoint. In this paper, we report the observation of Pockels effect by Mach-Zehnder interferometer in polycrystalline ceramics made from a ternary silicate glass via crystallization due to heat-treatment, i.e., glass-ceramics. Since the silicate system is employed as the precursor, merits of glass material are fully utilized to fabricate the optical device component, in addition to that of functional crystalline material, leading us to provide an electro-optic device, which is introducible into glass-fiber network.

  13. USE OF LOCAL NATURAL SILICEOUS RAW MATERIAL AND WASTES FOR PRODUCTION OF HEAT-INSULATING FOAMCONCRETE

    Directory of Open Access Journals (Sweden)

    V. U. Matsapulin

    2015-01-01

    Full Text Available The article analyzes the resource base, reserves and the use of siliceous rocks, their economic feasibility of the use for production of building materials of new generation with low-energy and other costs. Presented are the results of laboratory research and testing technology of production of insulating foam from a composition based on an aqueous solution of sodium silicate obtained from the local siliceous rocks (diatomite and the liquid alkali component - soapstock, hardener from ferrochrome slag and waste carbonate rock able to harden at a low temperature processing ( 100-110 ° C.

  14. Production of reactive oxygen species from abraded silicates. Implications for the reactivity of the Martian soil

    DEFF Research Database (Denmark)

    Bak, Ebbe Norskov; Zafirov, Kaloyan; Merrison, Jonathan P.

    2017-01-01

    to oxidants in the form of hydrogen peroxide (H2O2) and hydroxyl radicals (⋅OH). We found that silicate samples abraded in simulated Martian atmospheres gave rise to a significant production of H2O2 and ⋅OH upon contact with water. Our experiments demonstrated that abraded silicates could lead to a production...... of H2O2 facilitated by atmospheric O2 and inhibited by carbon dioxide. Furthermore, during simulated saltation the silicate particles became triboelectrically charged and at pressures similar to the Martian surface pressure we observed glow discharges. Electrical discharges can cause dissociation of CO...

  15. Carbonate formation in non-aqueous environments by solid-gas carbonation of silicates

    Science.gov (United States)

    Day, S. J.; Thompson, S. P.; Evans, A.; Parker, J. E.

    2012-02-01

    We have produced synthetic analogues of cosmic silicates using the Sol Gel method, producing amorphous silicates of composition Mg(x)Ca(1-x)SiO3. Using synchrotron X-ray powder diffraction on Beamline I11 at the Diamond Light Source, together with a newly-commissioned gas cell, real-time powder diffraction scans have been taken of a range of silicates exposed to CO2 under non-ambient conditions. The SXPD is complemented by other techniques including Raman and Infrared Spectroscopy and SEM imaging.

  16. The distribution of chromium among orthopyroxene, spinel and silicate liquid at atmospheric pressure

    Science.gov (United States)

    Barnes, S. J.

    1986-01-01

    The Cr distributions for a synthetic silicate melt equilibrated with bronzitic orthopyroxene and chromite spinel between 1334 and 1151 C over a range of oxygen fugacities between the nickel-nickel oxide and iron-wuestite buffers are studied. The occurrence, chemical composition, and structure of the orthopyroxene-silicate melt and the spinel-silicate melt are described. It is observed that the Cr content between bronzite and the melt increases with falling temperature along a given oxygen buffer and decreases with falling oxygen fugacity at a given temperature; however, the Cr content of the melt in equilibrium with spinel decreases with falling temperature and increases with lower oxygen fugacity.

  17. Metal - Silicate Separation in a Deformation Regime: Implications for Early Differentiation Processes

    Science.gov (United States)

    Rushmer, T.; Jones, J. H.; Gaetani, G.; Zanda, B.

    2001-12-01

    The segregation of metallic cores from silicate mantles is one of the earliest, and most important, differentiation process involved in the evolution of the Earth and other terrestrial planetary bodies. The physical segregation of Fe-rich metal from silicate imparted a strong geochemical signature on early silicate mantles due to the preferential incorporation of siderophile elements into the core. Reconciling our estimates of primary bulk silicate mantle with candidate planetary bulk compositions requires an understanding of the geochemical consequences of the different regimes in which core forming material may have been mobile. This includes not only the possible differentiation processes that occurred in the terrestrial planets, but also understanding the differentiation processes in the meteorite parent bodies. Although a magma ocean model is possible for efficient core formation, some scenarios call for segregation of the core from solid silicate and the geochemical consequences can be significantly different. Experimental studies are one way in which insight can be gained into the possible geochemical signatures of metal-silicate segregation. Deformation experiments in addition provide a dynamic component, which allows liquid metal to segregate from solid silicate. Starting materials are cored from a slab of the Kernouve fall which is composed of olivine, pyroxene, plagioclase, chromite and chlorapatite; Fe-Ni metal and sulfide form 20-25% of the sample. Experimental conditions are 1.0-1.4 GPa confining pressure with strain rates of 10-4/s to 10-6/s. Temperatures ranging from 900° C to 1050° C produce variable amounts of silicate melt and different mechanisms of metal segregation are observed. In experiments which are below the silicate solidus, mobility of FeS is extensive and deformation textures are cataclastic. Geochemical analyses shows that migration of Fe-S-Ni-O metal through fractures and along grain boundaries produces extensive modification to

  18. Lifetime Predictions of a Titanium Silicate Glass with Machined Flaws

    Science.gov (United States)

    Tucker, Dennis S.; Nettles, Alan T.; Cagle, Holly

    2003-01-01

    A dynamic fatigue study was performed on a Titanium Silicate glass to assess its susceptibility to delayed failure and to compare the results with those of a previous study. Fracture mechanics techniques were used to analyze the results for the purpose of making lifetime predictions. The material strength and lifetime was seen to increase due to the removal of residual stress through grinding and polishing. Influence on time-to-failure is addressed for the case with and without residual stress present. Titanium silicate glass otherwise known as ultra-low expansion (ULE)* glass is a candidate for use in applications requiring low thermal expansion characteristics such as telescope mirrors. The Hubble Space Telescope s primary mirror was manufactured from ULE glass. ULE contains 7.5% titanium dioxide which in combination with silica results in a homogenous glass with a linear expansion coefficient near zero. delayed failure . This previous study was based on a 230/270 grit surface. The grinding and polishing process reduces the surface flaw size and subsurface damage, and relieves residual stress by removing the material with successively smaller grinding media. This results in an increase in strength of the optic during the grinding and polishing sequence. Thus, a second study was undertaken using samples with a surface finish typically achieved for mirror elements, to observe the effects of surface finishing on the time-to-failure predictions. An allowable stress can be calculated for this material based upon modulus of rupture data; however, this does not take into account the problem of delayed failure, most likely due to stress corrosion, which can significantly shorten lifetime. Fortunately, a theory based on fracture mechanics has been developed enabling lifetime predictions to be made for brittle materials susceptible to delayed failure. Knowledge of the factors governing the rate of subcritical flaw growth in a given environment enables the development of

  19. Crystallisation mechanism of a multicomponent lithium alumino-silicate glass

    Energy Technology Data Exchange (ETDEWEB)

    Wurth, R. [Otto-Schott-Institut, Jena University, Fraunhoferstr. 6, 07743 Jena (Germany); Pascual, M.J., E-mail: mpascual@icv.csic.es [Instituto de Ceramica y Vidrio, CSIC, Kelsen 5, 28049 Madrid (Spain); Mather, G.C.; Pablos-Martin, A.; Munoz, F.; Duran, A. [Instituto de Ceramica y Vidrio, CSIC, Kelsen 5, 28049 Madrid (Spain); Cuello, G.J. [Institut Laue-Langevin, Boite Postale 156, 38042 Grenoble Cedex 9 (France); Ruessel, C. [Otto-Schott-Institut, Jena University, Fraunhoferstr. 6, 07743 Jena (Germany)

    2012-06-15

    A base glass of composition 3.5 Li{sub 2}O Bullet-Operator 0.15 Na{sub 2}O Bullet-Operator 0.2 K{sub 2}O Bullet-Operator 1.15 MgO Bullet-Operator 0.8 BaO Bullet-Operator 1.5 ZnO Bullet-Operator 20 Al{sub 2}O{sub 3} Bullet-Operator 67.2 SiO{sub 2} Bullet-Operator 2.6 TiO{sub 2} Bullet-Operator 1.7 ZrO{sub 2} Bullet-Operator 1.2 As{sub 2}O{sub 3} (in wt.%), melted and provided by SCHOTT AG (Mainz), was used to study the crystallisation mechanism of lithium alumino-silicate glass employing X-ray diffraction combined with neutron diffraction and non-isothermal differential scanning calorimetry (DSC). A high-quartz solid solution of LiAlSi{sub 2}O{sub 6} with nanoscaled crystals forms at 750 Degree-Sign C. Quantitative Rietveld refinement of samples annealed at 750 Degree-Sign C for 8 h determined a crystallised fraction of around 59 wt.%. The room temperature crystallised phase adopts an ordered, {beta}-eucryptite-like structure (2 Multiplication-Sign 2 Multiplication-Sign 2 cell) with Li ordered in the structural channels. The Avrami parameter (n {approx} 4), calculated from DSC data using different theoretical approaches, indicates that bulk crystallisation occurs and that the number of nuclei increases during annealing. The activation energy of the crystallisation is 531 {+-} 20 kJ mol{sup -1}. - Highlights: Black-Right-Pointing-Pointer Nanoscaled high-quartz crystals from a multicomponent lithium alumino-silicate glass. Black-Right-Pointing-Pointer Combined X-ray and neutron diffraction structural refinement. Black-Right-Pointing-Pointer {beta}-Eucryptite-like structure (2 Multiplication-Sign 2 Multiplication-Sign 2 cell) with Li ordered in the structural channels. Black-Right-Pointing-Pointer 3-Dimensional bulk crystallisation mechanism with an increasing number of nuclei. Black-Right-Pointing-Pointer Usage and validation of an alternative approach to calculate the Avrami parameter.

  20. Synthesis, characterization, crystal structure, DNA/BSA binding ability and antibacterial activity of asymmetric europium complex based on 1,10- phenanthroline

    Science.gov (United States)

    Alfi, Nafiseh; Khorasani-Motlagh, Mozhgan; Rezvani, Ali Reza; Noroozifar, Meissam; Molčanov, Krešimir

    2017-06-01

    A heteroleptic europium coordination compound formulated as [Eu(phen)2(OH2)2(Cl)2](Cl)(H2O) (phen = 1,10-phenanthroline), has been synthesized and characterized by elemental analysis, FT-IR spectroscopy, and single-crystal X-ray diffractometer. Crystal structure analysis reveals the complex is crystallized in orthorhombic system with Pca21 space group. Electronic absorption and various emission methods for investigation of the binding system of europium(III) complex to Fish Salmon deoxyribonucleic acid (FS-DNA) and Bovamin Serum Albumin (BSA) have been explored. Furthermore, the binding constants, binding sites and the corresponding thermodynamic parameters of the interaction system based on the van't Hoff equation for FS-DNA and BSA were calculated. The thermodynamic parameters reflect the exothermic nature of emission process (ΔH°DNA by non-intercalative mode which the groove binding is preferable mode. Also, the complex exhibits a brilliant antimicrobial activity in vitro against standard bacterial strains.

  1. Investigation on the co-luminescence effect of europium (III)-lanthanum(III)-dopamine-sodium dodecylbenzene sulfonate system and its application.

    Science.gov (United States)

    Si, Hailin; Zhao, Fang; Cai, Huan

    2013-01-01

    A novel luminescence, enhancement phenomenon in the europium(III)-dopamine-sodium dodecylbenzene sulfonate system was observed when lanthanum(III) was added. Based on this, a sensitive co-luminescence method was established for the determination of dopamine. The luminescence signal for the europium (III)-lanthanum(III)-dopamine-sodium dodecylbenzene sulfonate system was monitored at λ(ex) = 300 nm, λ(em) = 618 nm and pH 8.3. Under optimized conditions, the enhanced luminescence signal responded linearly to the concentration of dopamine in the range 1.0 × 10(-10)-5.0 × 10(-7) mol/L with a correlation coefficient of 0.9993 (n = 11). The detection limit (3σ) was 2.7 × 10(-11) mol/L and the relative standard deviation for 11 parallel measurements of 3.0 × 10(-8) mol/L dopamine was 1.9%. The presented method was successfully applied for the estimation of dopamine in samples of pharmaceutical preparations, human serum and urine. The possible luminescence enhancement mechanism of the system is discussed briefly. Copyright © 2013 John Wiley & Sons, Ltd.

  2. Europium-phenolic network coated BaGdF5 nanocomposites for tri-modal computed tomography/magnetic resonance/luminescence imaging.

    Science.gov (United States)

    Zhu, Wei; Liang, Shuang; Wang, Jing; Yang, Zhe; Zhang, Li; Yuan, Tianmeng; Xu, Zushun; Xu, Haibo; Li, Penghui

    2017-05-01

    Multifunctional nanocomposites based on BaGdF5 nanoparticles (NPs) and metal phenolic network (MPN) have been engineered as novel contrast agents for potential applications in X-ray computed tomography, magnetic resonance and luminescence imaging. The BaGdF5@MPN nanocomposites were synthesized at room temperature by coating BaGdF5 NPs with europium-phenolic network, which was obtained by the coordination of europium (III) with tannic acid (TA). The in vitro cytotoxicity assays against HepG2 cells revealed that the BaGdF5@MPN nanocomposites presented better cytocompatibility and lower cytotoxity than pure BaGdF5 NPs. In addition, vivid red and green luminescence can be observed by confocal laser scanning microscope (CLSM) from the BaGdF5@MPN nanocomposites laden HepG2 cells under the excitation of UV (390 nm) and visible light (440 nm), respectively. The longitudinal relaxivity value (r1) of the nanocomposites was 2.457 mM-1s-1. Moreover, the nanocomoposites exhibited X-ray computed tomography (CT) and T1-weighted magnetic resonance (MR) imaging capacities, and the intensities of the enhanced signals of in vitro CT and MR images were proportional to the concentrations of the nanocomposites. These results indicated that the as-prepared BaGdF5@MPN nanocomposites are promising contrast agents for CT/MR/luminescence imaging.

  3. Effective visible light-active boron and europium co-doped BiVO4 synthesized by sol-gel method for photodegradion of methyl orange.

    Science.gov (United States)

    Wang, Min; Che, Yinsheng; Niu, Chao; Dang, Mingyan; Dong, Duo

    2013-11-15

    Eu-B co-doped BiVO4 visible-light-driven photocatalysts have been synthesized using the sol-gel method. The resulting materials were characterized by a series of joint techniques, including XPS, XRD, SEM, BET, and UV-vis DRS analyses. Compared with BiVO4 and B-BiVO4 photocatalysts, the Eu-B-BiVO4 photocatalysts exhibited much higher photocatalytic activity for methyl orange (MO) degradation under visible light irradiation. The optimal Eu doping content is 0.8 mol%. It was revealed that boron and europium were doped into the lattice of BiVO4 and this led to more surface oxygen vacancies, high specific surface areas, small crystallite size, a narrower band gap and intense light absorbance in the visible region. The doped Eu(III) cations can help in the separation of photogenerated electrons. The synergistic effects of boron and europium in doped BiVO4 were the main reason for improving visible light photocatalytic activity. Copyright © 2013 Elsevier B.V. All rights reserved.

  4. Emission tunability and local environment in europium-doped OH{sup −}-free calcium aluminosilicate glasses for artificial lighting applications

    Energy Technology Data Exchange (ETDEWEB)

    Farias, Aline M.; Sandrini, Marcelo; Viana, José Renato M.; Baesso, Mauro L.; Bento, Antônio C.; Rohling, Jurandir H. [Departamento de Física, Universidade Estadual de Maringá, Av Colombo, 5790, 87020-900, Maringá, PR (Brazil); Guyot, Yannick [Laboratoire de Physico–Chimie des Matériaux Luminescents, Université de Lyon, Université Claude Bernard Lyon 1, Villeurbanne, UMR 5620 CNRS 69622 (France); De Ligny, Dominique [Department of Materials Science and Engineering, University of Erlangen Nürnberg, Martens str. 5, 91058, Erlangen (Germany); Nunes, Luiz Antônio O. [Instituto de Física de São Carlos, Universidade de São Paulo, Av. Trabalhador São-Carlense400, 13566-590, São Carlos, SP (Brazil); Gandra, Flávio G. [Instituto de Física Gleb Wataghin, Universidade Estadual de Campinas, 13083-859, Campinas, SP (Brazil); Sampaio, Juraci A. [Lab Ciências Físicas, Universidade Estadual Norte Fluminense, 28013-602, Campos Dos Goytacazes, RJ (Brazil); Lima, Sandro M.; Andrade, Luis Humberto C. [Grupo de Espectroscopia Óptica e Fototérmica, Universidade Estadual de Mato Grosso do Sul-UEMS, Dourados, MS, C. P. 351, CEP 79804-970 (Brazil); and others

    2015-04-15

    The relationship between emission tunability and the local environment of europium ions in OH{sup −}-free calcium aluminosilicate glasses was investigated, focusing on the development of devices for artificial lighting. Significant conversion of Eu{sup 3+} to Eu{sup 2+} was obtained by means of melting the glasses under a vacuum atmosphere and controlling the silica content, resulting in broad, intense, and tunable luminescence ranging from blue to red. Electron spin resonance and X-ray absorption near edge structure measurements enabled correlation of the luminescence behavior of the material with the Eu{sup 2+}/Eu{sup 3+} concentration ratio and changes in the surrounding ions' crystal field. The coordinates of the CIE 1931 chromaticity diagram were calculated from the spectra, and the contour maps showed that the light emitted from Eu{sup 2+} presented broad bands and enhanced color tuning, ranging from reddish-orange to blue. The results showed that these Eu doped glasses can be used for tunable white lighting by combining matrix composition and the adjustment of the pumping wavelength. - Highlights: • Eu{sup 2+}-doped OH{sup −} free calcium aluminosilicate glass as a new source for white lighting. • Correlation between emission tunability and local environment of europium ions. • Significant reduction of Eu{sup 3+} to Eu{sup 2+} by melting the glasses under vacuum atmosphere. • Broad, intense and tunable luminescence ranging from blue to red.

  5. Microstructure engineering of Portland cement pastes and mortars through addition of ultrafine layer silicates

    DEFF Research Database (Denmark)

    Lindgreen, Holger; Geiker, Mette; Krøyer, Hanne

    2008-01-01

    Pozzolanic submicron-sized silica fume and the non-pozzolanic micron- and nano-sized layer silicates (clay minerals) kaolinite, smectite and palygorskite have been used as additives in Portland cement pastes and mortars. These layer silicates have different particle shape (needles and plates...... is that the cement paste structure and porosity can be engineered by addition of selected layer silicates having specific particle shapes and surface properties (e.g., charge and specific surface area). This seems to be due to the growth of calcium-silicate hydrates (C-S-H) on the clay particle surfaces......), surface charge, and size (micron and nano). The structure of the resulting cement pastes and mortars has been investigated by atomic force microscopy (AFM), helium porosimetry, nitrogen adsorption (specific surface area and porosity), low-temperature calorimetry (LTC) and thermal analysis. The main result...

  6. Some observations on use of siliceous mineral waters in reduction of corrosion in RCC structures

    Digital Repository Service at National Institute of Oceanography (India)

    Venugopal, C.

    The corrosion-resisting characteristics of reinforcement in cement blended with siliceous mineral wastes viz. gold tailing and flyash have been evaluated by using an accelerated corrosion technique. The additions of these mineral admixtures...

  7. Geotechnical properties of two siliceous cores from the central Indian Ocean

    Digital Repository Service at National Institute of Oceanography (India)

    Khadge, N.H.

    Physical properties of the siliceous sediments from the Central Indian Basin are measured on two short cores. The properties such as water content, Atterberg limits, porosity specific gravity, wet density show the medium to high plastic sediment...

  8. Black silicate paints: Formulation and performance data on OSO-H

    Science.gov (United States)

    Schutt, J. B.; Shai, C. M.

    1973-01-01

    Formulations and general procedures are given for making and applying space environmentally, as well as atmospherically stable black silicate paints. Compositions are given which meet spacecraft self-contamination requirements, have excellent heat resistance, and are strongly semiconductive.

  9. Polymer Derived Rare Earth Silicate Nanocomposite Protective Coatings for Nuclear Thermal Propulsion Systems Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The objective of this Phase I SBIR program is to develop polymer derived rare earth silicate nanocomposite environmental barrier coatings (EBC) for providing...

  10. Carbonation of metal silicates for long-term CO.sub.2 sequestration

    Energy Technology Data Exchange (ETDEWEB)

    Blencoe, James G.; Palmer, Donald A.; Anovitz, Lawrence M.; Beard, James S.

    2017-08-01

    In a preferred embodiment, the invention relates to a process of sequestering carbon dioxide. The process comprises the steps of: (a) reacting a metal silicate with a caustic alkali-metal hydroxide to produce a hydroxide of the metal formerly contained in the silicate; (b) reacting carbon dioxide with at least one of a caustic alkali-metal hydroxide and an alkali-metal silicate to produce at least one of an alkali-metal carbonate and an alkali-metal bicarbonate; and (c) reacting the metal hydroxide product of step (a) with at least one of the alkali-metal carbonate and the alkali-metal bicarbonate produced in step (b) to produce a carbonate of the metal formerly contained in the metal silicate of step (a).

  11. Polymer Derived Yttrium Silicate Ablative TPS Materials for Next-Generation Exploration Missions Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Through the proposed NASA SBIR program, NanoSonic will optimize its HybridSil® derived yttrium silicates to serve as next-generation reinforcement for carbon...

  12. USE OF LOCAL NATURAL SILICEOUS RAW MATERIAL AND WASTES FOR PRODUCTION OF HEAT-INSULATING FOAMCONCRETE

    National Research Council Canada - National Science Library

    V. U. Matsapulin; A. B. Toturbiev; V. I. Toturbiev; B. D. Toturbieva; V. I. Cherkashin

    2015-01-01

    The article analyzes the resource base, reserves and the use of siliceous rocks, their economic feasibility of the use for production of building materials of new generation with low-energy and other costs...

  13. Polymer Derived Rare Earth Silicate Nanocomposite Protective Coatings for Nuclear Thermal Propulsion Systems Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Leveraging a rapidly evolving state-of-the-art technical base empowered by Phase I NASA SBIR funding, NanoSonic's polymer derived rare earth silicate EBCs will...

  14. THE ALUMINA-SILICATES IN STABILIZATION PROCESSES IN FLUIDIZED-BED ASH

    Directory of Open Access Journals (Sweden)

    IVANA PERNA

    2011-03-01

    Full Text Available Presented study of coal fluidized-bed ash solidification was accompanied with specific studies of alumino-silicates residues in ashes. The specific technology of fluid coal burning and its relatively low temperature combustion combines coal burning and decomposition of calcium carbonate added to the fluid layer in the main endeavor to capture all sulfur oxides. The burning temperature seems be decisive to the behavior of clayed residues and calcium carbonate decomposition in connection for the future solidification of fluidized bed ash. The calcareous substances in combination with alumino-silicate residues form solid bodies where silicates play decisive role of long-term stability and insolubility of obtained solids. The position of aluminum ions in clayed residues of burned coal were studied by MAS-NMR with attention on aluminum ion coordination to oxygen and formation of roentgen amorphous phase of poly-condensed calcium alumina-silicate.

  15. Effects of soil drenching of water-soluble potassium silicate on ...

    African Journals Online (AJOL)

    Effects of soil drenching of water-soluble potassium silicate on commercial avocado ( Persea americana Mill.) orchard trees infected with Phytophthora cinnamomi Rands on root density, canopy health, induction and concentration of phenolic com.

  16. [Colonization of silicate bacterium strain NBT in wheat roots].

    Science.gov (United States)

    Sheng, Xiafang

    2003-11-01

    The strain NBT of silicate bacterium was labelled with streptomycin, and a stable streptomycin resistance strain NBT was obtained. Its colonization dynamics and affecting factors in wheat rhizosphere were studied in agar plates and greenhouse pots were studied by counting the method with selective medium. The results of pot culture experiment showed that strain NBT could successfully colonize in the rhizosphere of wheat. In pot cultures of sterile soil, the highest colonization level (3.4 x 10(7) cfu.g-1 root soil) was reached on 9th day after seeds sown; at 54th day, the population of strain NBT tended to stable, and decreased to 1.4 x 10(4) cfu.g-1 root soil. In pot cultures of unsterile soil, the highest colonization level (3.8 x 10(7) cfu.g-1 root soil) was reached at 9th day, and the population of strain NBT tended to a stationary state at 60th day, with the numbers being 1.4 x 10(4) cfu.g-1 root soil. Some biological and abiotic factors could greatly influence the colonization of the beneficial microorganism.

  17. Optical analysis of samarium doped sodium bismuth silicate glass.

    Science.gov (United States)

    Thomas, V; Sofin, R G S; Allen, M; Thomas, H; Biju, P R; Jose, G; Unnikrishnan, N V

    2017-01-15

    Samarium doped sodium bismuth silicate glass was synthesized using the melt quenching method. Detailed optical spectroscopic studies of the glassy material were carried out in the UV-Vis-NIR spectral range. Using the optical absorption spectra Judd-Ofelt (JO) parameters are derived. The calculated values of the JO parameters are utilized in evaluating the various radiative parameters such as electric dipole line strengths (Sed), radiative transition probabilities (Arad), radiative lifetimes (τrad), fluorescence branching ratios (β) and the integrated absorption cross- sections (σa) for stimulated emission from various excited states of Sm3+‡ ion. The principal fluorescence transitions are identified by recording the fluorescence spectrum. Our analysis revealed that the novel glassy system has the optimum values for the key parameters viz. spectroscopic quality factor, optical gain, stimulated emission cross section and quantum efficiency, which are required for a high performance optical amplifier. Calculated chromaticity co-ordinates (0.61, 0.38) also confirm its application potential in display devices. Copyright © 2016 Elsevier B.V. All rights reserved.

  18. A New Biphasic Dicalcium Silicate Bone Cement Implant

    Directory of Open Access Journals (Sweden)

    Fausto Zuleta

    2017-07-01

    Full Text Available This study aimed to investigate the processing parameters and biocompatibility of a novel biphasic dicalcium silicate (C2S cement. Biphasic α´L + β-C2Sss was synthesized by solid-state processing, and was used as a raw material to prepare the cement. In vitro bioactivity and biocompatibility studies were assessed by soaking the cement samples in simulated body fluid (SBF and human adipose stem cell cultures. Two critical-sized defects of 6 mm Ø were created in 15 NZ tibias. A porous cement made of the high temperature forms of C2S, with a low phosphorous substitution level, was produced. An apatite-like layer covered the cement’s surface after soaking in SBF. The cell attachment test showed that α´L + β-C2Sss supported cells sticking and spreading after 24 h of culture. The cement paste (55.86 ± 0.23 obtained higher bone-to-implant contact (BIC percentage values (better quality, closer contact in the histomorphometric analysis, and defect closure was significant compared to the control group (plastic. The residual material volume of the porous cement was 35.42 ± 2.08% of the initial value. The highest BIC and bone formation percentages were obtained on day 60. These results suggest that the cement paste is advantageous for initial bone regeneration.

  19. Mesoporous Calcium Silicate Nanoparticles with Drug Delivery and Odontogenesis Properties.

    Science.gov (United States)

    Huang, Ching-Yuang; Huang, Tsui-Hsien; Kao, Chia-Tze; Wu, Yuan-Haw; Chen, Wan-Chen; Shie, Ming-You

    2017-01-01

    Calcium silicate (CS) -based materials play an important role in the development of endodontic materials that induce bone/cementum tissue regeneration and inhibit bacterial viability. The aim of this study was to prepare novel mesoporous CS (MesoCS) nanoparticles that have osteogenic, drug delivery, and antibacterial characteristics for endodontic materials and also have an excellent ability to develop apatite mineralization. The MesoCS nanoparticles were prepared using sol-gel methods. In addition, the mesoporous structure, specific surface area, pore volume, and morphology of the MesoCS nanoparticles were analyzed. The apatite mineralization ability, in vitro odontogenic differentiation, drug delivery, and antibacterial properties of the MesoCS nanoparticles were further investigated. The results indicate that the 200-nm-sized MesoCS nanoparticles synthesized using a facile template method exhibited a high specific surface area and pore volume with internal mesopores (average pore size = 3.05 nm). Furthermore, the MesoCS nanoparticles can be used as drug carriers to maintain sustained release of gentamicin and fibroblast growth factor-2 (FGF-2). The MesoCS-loaded FGF-2 might stimulate more odontogenic-related protein than CS because of the FGF-2 release. Based on this work, it can be inferred that MesoCS nanoparticles are potentially useful endodontic materials for biocompatible and osteogenic dental pulp tissue regenerative materials. Copyright © 2016 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  20. A New Biphasic Dicalcium Silicate Bone Cement Implant

    Science.gov (United States)

    Murciano, Angel; Maté-Sánchez de Val, José E.

    2017-01-01

    This study aimed to investigate the processing parameters and biocompatibility of a novel biphasic dicalcium silicate (C2S) cement. Biphasic α´L + β-C2Sss was synthesized by solid-state processing, and was used as a raw material to prepare the cement. In vitro bioactivity and biocompatibility studies were assessed by soaking the cement samples in simulated body fluid (SBF) and human adipose stem cell cultures. Two critical-sized defects of 6 mm Ø were created in 15 NZ tibias. A porous cement made of the high temperature forms of C2S, with a low phosphorous substitution level, was produced. An apatite-like layer covered the cement’s surface after soaking in SBF. The cell attachment test showed that α´L + β-C2Sss supported cells sticking and spreading after 24 h of culture. The cement paste (55.86 ± 0.23) obtained higher bone-to-implant contact (BIC) percentage values (better quality, closer contact) in the histomorphometric analysis, and defect closure was significant compared to the control group (plastic). The residual material volume of the porous cement was 35.42 ± 2.08% of the initial value. The highest BIC and bone formation percentages were obtained on day 60. These results suggest that the cement paste is advantageous for initial bone regeneration. PMID:28773119